materiais e processos sustentÁveis · 2017. 11. 27. · materiais e processos sustentÁveis...
TRANSCRIPT
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S I M P Ó S I O 2 0 1 2
MATERIAIS E PROCESSOS SUSTENTÁVEIS
COVILHÃ, UNIVERSIDADE DA BEIRA INTERIOR6-7 DE DEZEMBRO DE 2012
LIVRO DE ACTAS
Unidade de Materiais Têxteis e Papeleiros
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Reservados todos os direitos
Título:Actas do Simpósio 2012: MATERIAIS E PROCESSOS SUSTENTÁVEIS
UMTP, Universidade da Beira Interior
6-7 de Dezembro de 2012, Covilhã - Portugal
Coordenador da Edição:Manuel José dos Santos Silva
Comissão Organizadora:Manuel José dos Santos Silva
Ana Maria Carreira Lopes
José Mendes Lucas
Rogério Simões
Álvaro Campos Vaz
Madalena Rocha Pereira
Maria José Pacheco
Ana Paula Costa
Carla Sofia Gaiolas
Isabel G. Trindade
Susana Ramos
Comissão Científica:Manuel José dos Santos Silva
Ana Maria Carreira Lopes
José Mendes Lucas
Rogério Simões
Albertina Amaro
Madalena Rocha Pereira
Dina Mendonça
José Albertino Figueiredo
Ana Maria Ramos
Rui Miguel
Apoio Técnico:Maria da Conceição Camisão
Execução Gráfica:Serviços Gráficos da Universidade da Beira Interior
Tiragem:550 exemplares
ISBN:978-989-654-114-9
Depósito Legal:366483/13
Apoios:
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ÍNDICE
Programa da Conferência / Conference Programme ........................................................................ 9
Fabrics, modularity and technology in the development of fashion accessories: a step closer tosustainability, L. Ribeiro, R. Miguel, M. Pereira, J. Lucas, I. G. Trindade .......................... 15
Vestuário Técnico para o Quotidiano, C. A. Lopes, M. J. Geraldes ........................................ 19
Etiquetas Têxteis com a Integração de Símbolos para Interpretação de Cores em Padrões pelosDaltónicos, F. Craveiro, J. Lucas .................................................................................................... 21
Contribution to the structural characterization of Nano Structured Polymeric Materials using a 3DComputational Simulation Model, J. M. R. Curto, E. L. T. Conceição, P. A. F. Rodrigues, N.J. R. Belino, A. T. G. Portugal, R. M. S. Simões, M. J. S. Silva ....................................... 25
Sistema para análise da formação da folha de papel por retrodifusão e transmissão da radiaçãolaser, A. O. Mendes, P. T. Fiadeiro, M. V. Bernardo, A. P. Costa, M. E. Amaral, M. N.Belgacem .............................................................................................................................................. 29
Anaerobic treatment of olive mill wastewater: profile of sugars, organic acids and phenolic compounds,L. R. Fernandes, A. Gomes, A. Lopes, R. M. Simões .............................................................. 33
Influence of the experimental conditions on the electrodegradation of tetracyclines, A. Fernandes,C. Oliveira, N. Monteiro, C. Brinzilla, M. J. Pacheco, L. Ciríaco, A. Lopes ................... 37
A new medical textile: L-cysteine functionalized cotton, its mechanism of action and potential antimicrobialproperties, M. Pedrosa, E. Caldeira, F. Silva, A. Oliveira, I. Gouveia ................................ 40
Treatment of cork processing industrial effluent with an innovative system of Constructed Wetlandand Ozonation, Diana Santos, Williams Silva, Arlindo Gomes, Rogério Simões, Roberto Pascoa1,António Albuquerque, Alexandros Stefanakis ............................................................................... 46
Conduct1ive Textiles Functionalize with a Vapor Phase Polymerization Reactor, J. Matos, I. G.Trindade, J. Lucas, R. Miguel, A. Rute, M. Magrinho, M. Pereira, M. Santos Silva .... 50
Electrochemical techniques for pollution abatement in sanitary landfills, E. Catalão, A. Fernandes,P. Luz, R. Simões, M. J. Pacheco, L. Ciríaco, A. Lopes ........................................................ 54
DAPP as affinity ligand: support characterization and chromatographic studibs with plasmid DNA,Catarina Caramelo Nunes, Paulo Almeida, João C. Marcos, Cândida T. Tomaza ........... 57
Effect of continuous thermal stabilization process on thermal transitions and mechanical propertiesof a false-twist textured Polylactide multifilament, A. M. Manich, M. Martí, J. Carilla, B. Baena,D. Cayuela ........................................................................................................................................... 60
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Estratégias e Práticas Sustentáveis em Empresas da Cadeia Têxtil, M. Pereira, R. Miguel, J.Lucas, M. Santos Silva, I. Trindade ............................................................................................. 65
Influence of ionic strength o1n the AO8 ionization, M. J. R. G. Pires, M. I. A. Ferra, A.Marques ................................................................................................................................................ 71
Fabricação de materiais têxteis compósitos sustentáveis com matriz de Hevea Brasiliensis e reforçoem malhas, E. Garcia, M. J. Geraldes ......................................................................................... 74
Ferrocene Derivatives with Potential Biological Activity, S. Santos, J. A. Figueiredo, M. I. Ismael,A. C. Fernandes ................................................................................................................................. 78
Synthesis and characterization of iminosugars, M. Domingues, J. A. Figueiredo, M. Schuler, A.Tatibouët, M. I. Ismael ..................................................................................................................... 80
Desenvolvimento de uma Ferramenta Electrotêxtil para Aferição da Qualidade do Sono atravésdo Índice de Pitsburgh, M. Tavares, N. Belino, M. Patto, M. J. Geraldes .......................... 82
Antibacterial properties of some naturally occurring phenols against Staphylococcus aureus, Â.Luís, A. P. Duarte, F. Domingues .................................................................................................. 86
Preparation and Characterization of TiO2/WO
3 nanocomposites films for photocatalytic applications,
L. C. Silva, M. E. Melo Jorge, S. Sério ..................................................................................... 90
Photocatalytic degradation of Rhodamine 62G by nanocrystalline Ca0.6
Ho0.4
MnO3 film under visible
light, B. Barrocas, A. Rovisco, Y.Nunes, S. Sério, M. E. Melo Jorge .................................. 94
Antioxidant activity of solvent extracts from Vitex agnus-castus L., Diogo Pereira, Carla Gaiolas,Jesus Rodilla, Rosalina Mata, Lúcia Silva .................................................................................. 98
Higher Education in Fashion Design - A Course of Research, E. Lima, M. Calado, R. Miguel .... 100
Natural Dyes: The benefits of Biotechnology and its application in textiles, Gabriela da CunhaSantos, Cristina Carvalho .............................................................................................................. 104
Cold-plasma assisted gra1fting of cellulose fibers by acryli1c monomers, C. Gaiolas, M. E. Amaral,A. P. Costa, M. J. Santos Silva, M. N. Belgacem ...................................................................110
POSTERS
New N-alkyl-2-alkylsulfanylacetanilide atropisomers: synthesis and VT NMR study, S. S. Almeida,R. E. F. Boto, S. S. Ramos, P. Almeida ......................................................................................115
Pulping Potential of Ailanthus altissima (Mill.) Swingle, P. Baptista, A. P. Costa, M. E. Amaral,R. Simões .............................................................................................................................................117
Environmental applications of TiO2 electrodes prepared by DC-Magnetron Sputtering, S. Ferreira,
S. Sério, M. E. Melo Jorge, L. Ciríaco, M. J. Pacheco, A. Lopes ................................... 121
Heavy metals monitoring during the electrochemical treatment of municipal landfill leachates, A.D. Fonseca, P. Spranger, A. Fernandes, L. Ciríaco, A. Lopes, M. J. Pacheco .............. 125
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Removal of Reactive Orange 16 by Biosorption, C. Louro, I. Gonçalves, M. I. Ferra, H. M.Pinheiro ............................................................................................................................................... 128
Critical temperature and free energy of activation evaluation of new 2-alkoxy-N-alkylacetanilideatropisomers, P. M. S. Leite, S. S. Ramos, R. E. F. Boto, P. Almeida ................................ 130
Simulações de Antenas Têxteis, C. Loss, R. Salvado, P. Pinho, R. Gonçalves .................. 132
Sesquiterpenes from Croton gratissimus, L. I. N. Canelo, I. Mafuca, A. R. Estebainha, D. I.Mendonça, R. S. Mata ................................................................................................................... 136
Covalent and non-covalent strategies for surface modification of different textile materials withantimicrobial properties, F. Nogueira, P. Teixeira, E. Piskin, I. Gouveia .............................. 137
Malharia Funcional no segmento Infantil: O Body “Dry Baby”, A. L. Olivete, M. J. Geraldes .. 139
Sustainability in Fashion: Best Practices, Madalena Pereira, Rui Miguel, Paulo Martins, LilianaPina, Liliana Ribeiro ....................................................................................................................... 143
Epoxidação do Guaiol e seus derivados, Sofia Pombal, Jesus Rodilla, Lúcia Silva ........... 144
Trihalomethanes formation in treated wastewaters, A. S. Rebelo, M. I. A. Ferra, R. Oliveira,A. Marques, I. Gonçalves .............................................................................................................. 146
Phenolic compounds in cork processing wastewater, Diana Santos, Nicole Canto, Roberto Páscoa,Lúcia Silva, Rogério Simões, Arlindo Gomes ............................................................................ 148
Antioxidant activity of extracts from leaves of Betula celtiberica, Ana Serra, Arlindo Gomes, LúciaSilva ..................................................................................................................................................... 151
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PROGRAMA DA CONFERÊNCIA / CONFERENCE PROGRAMME
Thursday, 6 December
09.00 - 09.30 Registration, Anfiteatro 8.1, Faculty of Engineering
09.30 - 10.00 WELCOME SESSION AND PRESENTATION OF THE RESEARCH UNITOF TEXTILE AND PAPER MATERIALSAna Paula Coelho Duarte, Vice-Rector for Research and Innovation andCoordinator of the Research InstituteManuel José dos Santos Silva, Coordinator of the MTP research unit
10.00 - 12.30 SESSION IChairpersons: Rogério Simões, José Lucas and Ana Lopes
10.00 - 10.30 Paper, an example of an architectured materialJean-Francis BlochPagora, Ecole internationale du papier, de la communication imprimée et des biomatériaux,
Institut Polytechnique de Grenoble, France
10.30 - 10.50 Fabrics, modularity and technology in the development of fashion accessories:a step closer to sustainabilityL. Ribeiro, R. Miguel, M. Pereira, J. Lucas, I. G. TrindadeTextile and Paper Materials R&D Unit, Textile Science and Technology Department, University
of Beira Interior, Covilhã, Portugal
10.50 - 11.10 Vestuário Técnico para o QuotidianoC. A. Lopes, M. J. GeraldesUnidade de I&D de Materiais Têxteis e Papeleiros, Departamento de Ciência e Tecnologia
Têxteis, Universidade da Beira Interior, Covilhã, Portugal
11.10 - 11.30 Coffee Break and Poster Session
11.30 - 11.50 Etiquetas Têxteis com a Integração de Símbolos para Interpretação de Coresem Padrões pelos DaltónicosF. Craveiro, J. Lucas, R. Miguel, M. Santos Silva, M. PereiraUnidade de I&D Materiais Têxteis e Papeleiros, Departamento de Ciência e Tecnologia Têxteis,Universidade da Beira Interior, Covilhã, Portugal
11.50 - 12.10 Contribution to the structural characterization of Nano Structured PolymericMaterials using a 3D Computational Simulation ModelJ.M.R. Curto1, E. L. T. Conceição2, P. A. F. Rodrigues1, N. J. R. Belino1, A.T. G. Portugal2, R. M. S. Simões1, M. J. S. Silva1
1 University of Beira Interior, Textile and Paper Materials Research Unit., Rua Marquês d’Ávila
e Bolâma, Covilhã, Portugal.2 University of Coimbra, Chemical Engineering Dep., Pólo II, Rua Sílvio Lima - Coimbra. Portugal
12.10 - 12.30 Sistema para análise da formação da folha de papel por retrodifusão etransmissão da radiação laserA. O. Mendes1, P. T. Fiadeiro1,2, M. V. Bernardo1, A. P. Costa2, M. E. Amaral2,M. N. Belgacem3
1 Unidade de Deteção Remota, Universidade da Beira Interior, 6201-001 Covilhã, Portugal
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2 Unidade de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, 6201-001 Covilhã,Portugal3 Grenoble INP-Pagora, Ecole internationale du papier, de la communication imprimée et desbiomatériaux, France
12.30 - 14.00 Lunch and Poster Session
14.40 - 17.30 SESSION IIChairpersons: Isabel Ferra and Maria José Geraldes
14.00 - 14.40 Jean-Yves DréanEcoconception et développement durable: expérience de l’ENSISA en enseignementet en recherche”.
14.40 - 15.00 Anaerobic treatment of olive mill wastewater: profile of sugars, organic acidsand phenolic compoundsL. R. Fernandes, A. Gomes, A. Lopes, R. M. SimõesUnidade de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, Covilhã, Portugal
15.00 - 15.20 Influence of the experimental conditions on the electrodegradation oftetracyclinesA. Fernandes1, C. Oliveira1, N. Monteiro, C. Brinzilla2, M. J. Pacheco1, L. Ciríaco1,A. Lopes1
1 UMTP and Department of Chemistry, University of Beira Interior, Covilhã, Portugal2 Faculty of Electrical Engineering, The “Gheorghe Asachi” Technical University of Iasi, Iasi,Romania
15.20 - 15.40 A new medical textile: L-cysteine functionalized cotton, its mechanism ofaction and potential antimicrobial propertiesM. Pedrosa1,2, E. Caldeira1, F. Silva2, A. Oliveira2, I. Gouveia1
1 R&D Unit Textile and Paper Materials, University of Beira Interior, 6201-001 Covilhã, Portugal2 CICS-UBI - Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã,Portugal
15.40 - 16.20 Coffee Break
16.20 - 16.40 Treatment of cork processing industrial effluent with an innovative systemof Constructed Wetland and OzonationDiana Santos1, Williams Silva1, Arlindo Gomes1, Rogério Simões1, Roberto Pascoa1,António Albuquerque2, Alexandros Stefanakis3
1 Unity of Textile & Paper Materials and Department of Chemistry, University of Beira Interior,Covilhã - Portugal2 Department of Civil Engineering and Architecture, University of Beira Interior, Covilhã -Portugal3 Department of Environmental Engineering, Democritus University of Thrace, Thrace - Greece
16.40 - 17.00 Conductive Textiles Functionalized with a Vapor Phase Polymerization ReactorJ. Matos1, I. G. Trindade1, J. Lucas1,2, R. Miguel1,2, A. Rute1,3, M. Magrinho1,3,M. Pereira1,3, M. Santos Silva1,2
1 Unidade de I&D de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, Covilhã,Portugal2 Departamento de Ciência e Tecnologia Têxteis, Universidade da Beira Interior, Covilhã,Portugal3 Departamento de Química, Universidade da Beira Interior, Covilhã, Portugal
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17.00 - 17.20 Electrochemical techniques for pollution abatement in sanitary landfillsE. Catalão, A. Fernandes, P. Luz, R. Simões, M. J. Pacheco, L. Ciríaco, A. LopesUMTP and Department of Chemistry, University of Beira Interior, Covilhã, Portugal
17.20 - 17.40 DAPP as affinity ligand: support characterization and chromatographic studieswith plasmid DNACatarina Caramelo Nunes1,2, Paulo Almeida1,2, João C. Marcos3, Cândida T. Tomaz1,2
1 CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D.
Henrique, 6200-506 Covilhã, Portugal2 Department of Chemistry, University of Beira Interior, Rua Marquês d’Ávila e Bolama,
6201-001 Covilhã, Portugal3 Center of Chemistry, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
17.40 - 17.30 Discussion and Poster Session
Friday, 7 December
09.30 - 13.00 SESSION IIIChairpersons: Manuel Santos Silva and Ana Paula Costa
09.30 - 10.00 Effect of continuous thermal stabilization process on thermal transitionsand mechanical properties of a false-twist textured PolylactidemultifilamentA. M. Manich¹, M. Martí¹, J. Carilla¹, B. Baena¹, D. Cayuela2
¹ IQAC-CSIC, Barcelona (Spain),² INTEXTER-UPC, Terrassa (Spain)
10.00 - 10.20 Estratégias e Práticas Sustentáveis em Empresas da Cadeia TêxtilM. Pereira, R. Miguel, J. Lucas, M. Santos Silva, I. TrindadeUnidade dos Materiais Têxteis e Papeleiros, Departamento de Ciência e Tecnologia Têxteis,Universidade da Beira Interior, Covilhã, Portugal
10.20 - 10.40 Influence of ionic strength on the AO8 ionizationM. J. R. G. Pires, M. I. A. Ferra, A. MarquesChemistry Department, University of Beira Interior, 6201-001 Covilhã
10.40 - 11.00 Fabricação de materiais têxteis compósitos sustentáveis com matriz de HeveaBrasiliensis e reforço em malhasE. Garcia, M. J. GeraldesUnidade dos Materiais Têxteis e Papeleiros, Departamento de Ciência e Tecnologia Têxteis,Universidade da Beira Interior, Covilhã, Portugal
11.30 - 11.30 Coffee Break and Poster Session
11.30 - 11.50 Ferrocene Derivatives with Potential Biological ActivityS. Santos1, J. A. Figueiredo1, M. I. Ismael1, A. C. Fernandes2
1 Departamento de Química, Unidade de Materiais Têxteis e Papeleiros, Universidade da BeiraInterior, Covilhã, Portugal2 Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Lisboa, Portugal
11.50 - 12.10 Synthesis of iminosugarsM. Domingues1, J.A. Figueiredo1, M. Schuler2, A. Tatibouët2, M. I. Ismael1
1 UMTP and Department of Chemistry, University of Beira Interior, Covilhã, Portugal2 ICOA - Institut de Chimie Organique et Analytique, University of Orléans, France
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12.10 - 12.30 Desenvolvimento de uma Ferramenta Electrotêxtil para Aferição da Qua-lidade do Sono através do Índice de PitsburghM. Tavares1, N. Belino1, M. Patto2, M. J. Geraldes1
1 Unidade de I&D Materiais Têxteis e Papeleiros, Universidade da Beira Interior, Departamento
Ciência e Tecnologia Têxteis, Covilhã, Portugal2 Universidade da Beira Interior, Departamento de Ciências da Saúde, Covilhã, Portugal
12.30 - 12.50 Antibacterial properties of some naturally occurring phenols againstStaphylococcus aureusÂ. Luís, A. P. Duarte, F. DominguesCICS-UBI Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Covilhã,Portugal
12.50 - 13.00 Discussion
13.00 - 14.30 Lunch and Poster Session
14.30 - 17.00 SESSION IVChairpersons: Madalena Pereira and Lúcia Silva
14.30 - 14.50 Preparation and Characterization of TiO2/WO3 nanocomposites films forphotocatalytic applicationsL. C. Silva1, M. E. Melo Jorge2, S. Sério1
1 CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade
Nova de Lisboa, 2829-516 Caparica, Portugal2 CCMM, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade
de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
14.50 - 15.10 Photocatalytic degradation of Rhodamine 6G by nanocrystalline Ca0.6
Ho0.4
MnO3
film under visible lightB. Barrocas1, A. Rovisco2, Y. Nunes2, S. Sério2, M. E. Melo Jorge1
1 CCMM, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidadede Lisboa, Campo Grande, 1749-016 Lisboa, Portugal2 CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia da UniversidadeNova de Lisboa, 2829-516 Caparica, Portugal
15.10 - 15.30 Antioxidant activity of solvent extracts from Vitex agnus-castus LDiogo Pereira, Carla Gaiolas, Jesus Rodilla, Rosalina Mata, Lúcia SilvaChemistry Department, Unit of Textile & Paper Materials, University of Beira Interior,6201-001- Covilhã, Portugal
15.30 - 16.00 Coffee Break
16.00 - 16.20 Ensino Superior em Design de Moda - Um Percurso de InvestigaçãoE. Lima1, M. Calado2, R. Miguel1
1 Unidade de I&D Materiais Têxteis e Papeleiros, Departamento de Ciência e TecnologiaTêxteis, Universidade da Beira Interior, Covilhã, Portugal2 Faculdade de Arquitetura, Universidade Técnica de Lisboa, Portugal
16.20 - 16.40 Natural Dyes: The benefits of Biotechnology and its application intexti lesGabriela da Cunha Santos, Cristina CarvalhoCIAUD - Centro de Investigação de Arquitectura Urbanismo e Design - Faculdade de
Arquitectura da UTL
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16.40 - 17.00 Cold-plasma assisted grafting of cellulose fibers by acrylic monomersC. Gaiolas1, M. E. Amaral1, A. P. Costa1, M. J. Santos Silva1, M. N. Belgacem2
1 University of Beira Interior, Research Unit of Textile and Paper Materials, 6200-001 Covilhã,Portugal2 Grenoble INP-Pagora, Paper, print media and biomaterials, LPG2, Grenoble, France
17.00 - 17.30 DISCUSSION and FINAL SESSIONChairpersons: Manuel Santos Silva, Ana Lopes, José Lucas and Rogério Simões
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Fabrics, modularity and technology in the development of fashion accessories: a step closer to sustainability
L.Ribeiro , R.Miguel , M.Pereira, I.Trindade, J.Lucas Textile and Paper Materials Research Unit, Textile Science and Technology Department, University of Beira Interior
Pólo I Rua Marquês d'Ávila e Bolama, 6201-001 Covilhã, Portugal
Tel: +351275319700, Fax: +351275319768
Abstract This article results from an applied research project in collaboration with a textile firm located in Beira Interior. During this project the main objective has been the development of new patterns for wool fabric products for the company Fitecom. However, other objectives have been pursued, mainly the development of accessories with those fabrics, promoting differentiated applications beyond clothing products. Moreover, concerns about sustainability also support the work carried out until this stage. Concerning the raw materials, fabrics of natural fibers, 100% wool, were selected and for the design of the accessories, specifically bags, options of modularity were tested to extend the lifetime of the products, in a slow fashion perspective. The integration of technology, to increase the products value and consequently improve their lifetime, is also another solution proposed in this route to more sustainable products.
Introduction
In the fashion industry accessories play an important role along with clothing in the definition and expression of personality and social positions of individuals in the society [1, 2, 3]. Furthermore, in the design of fashion products in general, such as clothing and accessories, with the perspectives referred above, not only the aesthetics but also functionality aspects must be considered. The fashion accessory object of this study, the bag, since its existence has always been associated with basic transport functions, along with meanings of status and aesthetic. As well as in clothing, when producing bags the aesthetic and functional characteristics can be determined and influenced by the choices of the materials used. All throughout history a large variety of materials have been explored, for example, in the middle ages bags were mainly manufactured from leather, silk, linen fabric and from pieces of ecclesiastical robes, as well as wall hangings. In the twenty-first century, with the continuous technical innovations, new fibers and new materials, such as fabrics with soybean and bamboo fibers have been developed. But one of the big trends is the use of sustainable fabrics with organic cotton and wool, along with a growing concern for recycling and biodegradability [2, 3, 4, 5].
Taking into account the importance of aesthetics and functionality, and also pursue of more sustainable products, the role of design is extremely important. Concepts such as mass customization, slow design and slow fashion have gained attention during the last years, to attain more sustainable production and consume. Characteristics as modularity and a closer relationship between companies and consumers through co-creation and co-design [6, 7, 8, 9, 10, 11, 12] are some of the ways applied in the development of those products with add value, more quality and durability, extended lifetime, and consequently a longer lifecycle, because consumers more strongly connect to the them, not throwing them away so easily, as they do with fast fashion products. In this research, modularity and the integration of technology are proposed as options during the development stage as methods to extend the lifetime of bags.
Raw materials: wool fabrics
Wool fabrics were used in this research project as the main raw material to produce bags, mainly because in the region of Beira Interior there is a long tradition of producing and developing wool based fabrics and clothing, and also because it is one of the least explored materials in the development of bags as confirmed by our. A brief analysis to the use of fabrics in some recognized brands was done (tables 1, 2). Using fabrics with natural fibers, some in natural colors, without dying, is also a step for the development of more sustainable products (figure 1). It can be stated that wool fabrics can produce products with added value for the consumer; however it is necessary to understand the characteristics of the fabrics that consumers value most on items like bags [13]. For example, on wool clothing, characteristics such as comfort and protection (against heat or cold) are the most important, but in bags they are not so relevant. Characteristics such as waterproof and resistance may be more relevant in choosing bags of a certain material. Considering the features already highlighted of wool fabrics, these may be extended by subsequent treatments such as coatings and micro-encapsulation of various compounds. For this aspect, some tests were conducted using polyurethane and phosphorescent coatings for waterproofing and aesthetic purposes (figure 2).
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Table 1. Analysis of bag collections
Brands Fabrics: Cotton, Polyester, Wool
Other Materials: Leather, polyurethane
Number of available articles
Number of items
Percentage Number of items
Percentage Number of
items Percentage
Zara 10 6.9% 134 93.1% 144 100%
Lanidor 7 18.4% 31 81.6% 38 100%
Mango 9 6.7% 126 93.3% 135 100%
Salsa 10 28.6% 25 71.4% 35 100%
Pull and Bear 18 35.3% 33 64.7% 51 100%
Total 54 13,4% 349 86,6% 403 100%
Table 2. Analysis of fibers
Composition of fabrics used Bags with simple or mixed composition
Percentage of fibers used
Cotton (cotton; cotton and polyester) 30 49.2%
Wool ( wool; polyester and wool) 4 6.6%
Polyester (polyester; cotton and polyester; polyester and wool) 26 42.6%
Nylon 1 1.6%
Total 61 100%
Figure1. Fitecom fabrics 100% wool
Figure 2. Coating machine
Modular design
and imperfect formal approaches to modularity, it has been recognized for decades as a good design practice. The unrealized potential and growth of
[14]. Indeed modular design is far away from well explored as a tool for product development, but the advantages it brings for companies and consumers are worthy of attention. Modularity can be defined as a feature of the product, adding modules into its design. It can improve the reliability and quality of the product, enabling maintenance, repair, simple assembly or disassembly and differential consumption [15, 16]. Developing modular designs can also help to reduce costs in the production, when a family of products with the same modules is created [17]. In the context of fashion accessories, namely bags, modularity can be a solution for various issues, such as: when repeated use provokes damage in a specific part of the bag; when fashion raises the desire of following seasonal trends (spring/summer, fall/winter), urging a change of colors, fabrics and shapes (e.g. change of handles and pockets with different colors); when the choice of fabrics involves a specific intention (ex: waterproofed fabric during the winter), or when it offers different adaptations for a variety of occasions (e.g. use the same bag for day and night).
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In the current project some prototypes have been developed to test some options of modularity (figure 3, 4, 5, 6).
Figure 3. Handbag 100% wool fabrics: front panel yellow with coating and option with grey embroidered; two options of handles
Figure 4. Backpack 100% wool fabrics: modular base with coated fabric
Figure 5. Weekend bag 100% wool fabrics: modular handles and small optional bags
Figure 6. Briefcase 100% wool fabric coated: modular handles and pockets
Integration of technology
Technology is increasingly more present in our daily lives, from the most ordinary and simple objects to the most complex items, where the advances and progresses achieved are much more evident. In fashion products, such as clothing, the integration of smart functionalities is changing the culture around those products and the way the consumers interact and use them [18]. This new developed relationships can be understood by the term coined by Sabine Seymour [19], Fashionable Technology, as the intersection of design, fashion, science, and
Fashionable wearables accessories, or jewelry that combine aesthetics and style wit (p.12), therefore i s important that this integration is done without losing fashion sense, considering the aesthetic side, because i s almost inevitable that some components cannot be completely integrated and hidden on the accessories. As Suh, Carroll, and Cassill [20] appearance, technology must be simplified and invisible ,
as much as it can. If technology is not invisible, it should have an attractive appearance and become fashionable
In this project one of the objectives is to follow this approach, imbuing the integration of technology in a subtle way that considers and maintains the aesthetic and functional aspects of the manufactured goods. The integration of technology is presented here as an option to add value to the products [21,22], and a possible answer to concerns about security (e.g. opening with private code, system of location by GPS); or on the other side to more playful desires (e.g. integration of leds). For this purpose, some components that nowadays are common in wearable technology, such as connectors, wires, sensors, microprocessors, actuators, software, batteries, solar panels, wireless systems and with electronic textiles will be used [19].
Results and Discussion
In the sequence of the current research carried out with the wool firm some prototypes of bags made of 100% wool fabrics were developed, either with the fabrics in its natural state, or with polyurethane coatings, and options of modularity. The results are in concordance with the expectations, but it needs to be taken into consideration that a deep research on the applications of wool fabrics in bags is needed, as well as performance tests.
Conclusions
In the current research i s evident that the present environmental concerns, and also the technological evolution, aim for new roads in the design of fashionable accessories with aesthetic, functional and sustainable solutions, allowing a growth of value for the economy, on the basis of a university company relationship.
References
1. Barnard, 2002, Barnard, M., Fashion as communication, London, Routledge, 2002
2. Wilcox, C. , Bags, V & A Publishing, 1999 3. Pedersen, S., Handbags: What Every Woman Should Know, David & Charles, 2006 4. Nyamache, P. T. O. M., and Nyambura, M. S. R. (,
International journal of Multidisciplinary Management Studies, 2(4), 2012 5. Brand, J. and Teunissen, J., Fashion and Acessories, Terra Uitgeverij, 2007 6. Kim, B., Green design-Studies about fashion handbag, Design & Conceptual Design (CAIDCD), 2010 IEEE, 815 819, 2010 7. Kuo, D., Lin, C., and Wu, Y.,The connection between customer value creation and innovation strategy: A proposed framework and its implication in fashion
18
products. Procedding from 2011 IEEE International Conference, Industrial Engineering and Engineering Management (IEEM), 2011 8. Piller, F. T., and Tseng, M. M., Handbook of Research in Mass Customization and Personalization: Strategies and concepts. Strategies (Vol. 1). World Scientific, 2010 9. Prahalad, C. K., and Ramaswamy, V. , Co-creation experiences: The next practice in value creation. Journal of Interactive Marketing, 18(3), 5 14, 2004 10. Satam, D., Liu, Y., and Lee, H. J., Intelligent design systems for apparel mass customization. Journal of the Textile Institute, 37 41, 2011 11. Schulte, N., and Godoy, I., As dimensões da sustentabilidade aplicadas em produtos slow fashion. Resultados do Programa de Extensão Ecomoda UDESC fido.palermo.edu, 2012 12. Ulrich, P. V., Anderson-Connell, L. J., and Wu, W., Consumer co-design of apparel for mass customization. Journal of Fashion Marketing and Management, 7(4), 398 412, 2003 13. Pierlot, T. - Natural Advantages, 9th World Sheep and Wool Congress, Australia, CSIRO, 2010 14. Kusiak, A., Integrated product and process design: a modularity perspective. Journal of Engineering Design, 2002 15. Daniilidis, C., and Enßlin, A classification framework for product modularization methods. Proceedings of the 18th International Conference on Engineering Design, 2011 16. Newcomb, P., Bras, B., and Rosen, D., Implications of modularity on product design for the life cycle. ASME Design Engineering Technical Conferences and Computers in Engineering Conference (pp. 1 12), 1996 17. Luh, Y.-P., Chu, C.-H., and Pan, C.-C., Data management of green product development with generic modularized product architecture. Computers in Industry, 61(3), 223 234, 2010 18. Baurley, S., Interactive and experiential design in smart textile products and applications. Personal and Ubiquitous Computing, 8(3-4), 274 281, 2004 19. Seymour, S. Fashionable Technology: The Intersection of Design, Fashion, Science, and technology, Springer, 2008
20. Suh, M., Carroll, K., and Cassill, N.,Critical review of the smart clothing and product development. Journal of Textile and Apparel, Technology and Management, 6(4), 1 18, 2010
Acknowledgements
Project PT 21- Powered Textiles Século 21, PPS 3 Hightech Fashion, Projecto Mobilizador nº 13848,
Quadro de Referência Estratégico Nacional 2007-2013 (QREN)
19
Vestuário Técnico para o Quotidiano
C. A. Lopes, M. J. Geraldes.
Universidade da Beira Interior
Abstract
Realização de um projecto que visa dar a conhecer a potencialidade do desenvolvimento de produtos inovadores e a sua aplicação a um nível nacional. Assim, foi proposto o desenvovimento de um tipo de vestuário para o quotidiano, produzido com têxteis técnicos, na realização de peças versáteis, que transmitem conforto e funcionalidade no quotidiano do utilizador, com uma estética apelativa e que se adapte a qualquer ocasião que surja na vida do consumidor.
Introdução
Como o pensamento na situação actual do nosso país surgiu a ideia de criar uma marca de vestuário que se caracteriza por ser produzida com materiais portugueses e em Portugal, de forma a valorizar empresas nacionais que, apesar da crise, se adaptam às más circunstâncias através da criatividade e inovação. Este conceito teve como base um conhecimento aprofundado e directo com materiais têxteis técnicos de uma dessas empresas, a LMA (Leandro Manuel Araújo), assim como o facto de haver consumidores que se preocupam com o conforto no vestuário, não esquecendo a estética das mesmas, para além disto foi tido em conta algumas das marcas que evoluem neste sentido como, por exemplo, a Adidas (Y3), de utilizar têxteis técnicos em peças de vestuário mais apelativas para o quotidiano. Toda esta investigação surgiu pelo facto de que grande parte da indústria têxtil representa, segundo a Associação Têxtil e Vestuário de Portugal, 10% do total das exportações portuguesas; 19% de emprego na indústria transformadora, 8% do volume de negócios da indústria transformadora e 8% da produção de indústria transformadora, fazendo-a de facto uma das indústrias que envolve mais dinheiro e pessoas, não só em portugal como a um nível global. Para além da tentativa de produzir produtos confortáveis, funcionais, esteticamente apelativos e versáteis, pretendem-se produtos que satisfaçam as necessidades dos consumidores ao nível do vestuário para o dia-a-adia, assim como a possibilidade de abertura de novos postos de trabalho para contribuir de alguma forma para o crescimento das empresas portuguesas. Claro que é importante perceber o papel fundamental do design/designer como criador de bens que tem a preocupação de compreender melhor as necessidades do consumidor, para além dos seus desejos, mas a ter em conta as necessidades económicas, psicológicas e espirituais. Daí que o design de moda se preocupa em satisafazer essas necessidades através do vestuário, dos
materiais, pelos quais o consumidor se expressa a partir da sua indumentária que comunica uma linguagem, muito sua, para com a sociedade.
Materiais e Métodos
Os materiais utilizados para este projecto são provenientes da empresa anteriormente referida. Têxteis técnicos com propriedades de alto desempenho que pretendem melhorar o conforto, que são utilizados sobretudo no desporto, e que neste projecto foram trazidos para o quotidiano. O desempenho destes materiais é conseguido pela utilização de fibras especialmente desenvolvidas para uso no vestuário desportivo de alta competição, permitindo que este se comporte de deterninada maneira perante condições de alto risco para o ser humano. Utilizando estes materiais têxteis como método de protecção do ser humano , mas para o seu dia-a-dia, como forma de proteger das situações que surjam incluindo as mudanças climáticas repentinas que cada vez mais têm vindo a aumentar. Neste projecto foram apresentadas algumas propostas de peças chave produzidas com estes materiais, transmitindo ao futuro utilizador um visual apelativo e agradável ao toque. Dentro dessas propostas foram produzidas três peças, um blazer, uma camisa e uns leggins. Em que os materiais utilizados para a realização destas peças foram os seguintes: no blazer foi usado um tecido impermeável de forma a impedir a entrada de água, uso de uma rede no interior de forma a promover a resperabilidade e nas ombreiras a utilização de uma malha 3D para um melhor suporte de pesos; a camisa foi confeccionada com uma malha com propriedades dri-release, que permite uma secagem mais rápida da humidade que se encontre junto ao corpo, tendo no entanto um toque agradável como de um tecido de fibras naturais; nos leggins foi utilizado este mesmo tipo de malha, devido às suas propriedades de alto desempenho, na sua construção foi utilizado um rib (malha canelada) para dar uma boa elasticidade na zona da cintura sem que seja necessário acrescentar um elástico à peça, que por vezes se torna um incómodo na sua utilização.
20
Resultados e Discussão
Depois de ter sido realizada uma pesquisa de tendências (cores, materiais, texturas e formas) para desenvolvimento das peças, tornando-se possível uma boa aplicação dos materiais nas peças, trazendo ao vestuário outro tipo de funcionalidade, podendo melhorar ainda mais o conforto das peças. De facto a utilização destes materiais têxteis técnicos em peças mais clássicas do que as habituais desportivas, conseguiu-se um bom resultado numa forma diferente de ver o vestuário mais convencional, que pode
ser transformado por completo pelo tipo de material que é utilizado. Após o fabrico destas peças surgiu uma pequena questão, o que fazer com os desperdícios têxteis? Foi desta interrogação que nasceu uma pequena experiência no sentido da sustentabilidade ecológica com a criação de um produto feito com os desperdícios da confecção das peças e que é importante ter em conta, uma vez que ainda é uma grande parte da poluição a um nível global. Para a execução desta ideia foi produzida uma mala para o dia-a-dia com uso de formas geométricas regulares que é possível recortar desses restos.
Figure 1 Imagens das peças finais confeccioadas, blazer, camisa e leggins, respectivamente e mala produzida com desperdícios têxteis.
Nas imagens acima é possivel ver o resultado final das peças mencionadas, assim como a mala feita com os desperdícios têxteis que resultaram da confecção dessas peças.
Conclusões
É importante este tipo de desenvolvimento na área do vestuário a um nível nacional, com a utilização deste tipo de materiais têxteis técnicos. Considerando questões sociais, no sentido de prover mais ainda produtos, competências a um nível nacional, para além do que já é feito, e ecológicas no sentido de surgirem soluções na concepção de produtos, ou na resolução de problemas que surjam após a realização dos mesmos como a redução, reutilização e reciclagem, de desperdícios têxteis, ou de dar uma nova vida a um produto que deixou de cumprir a sua função principal.
Referências 1. Agis, D., Bessa, D., and Gouveia, J., Vaz, P., vestindo o
futuro - microtendências para a indústria textile, vestuário e moda até 2020 , ATP, 109, 2010.
2. Papanek, V., Design for the Real World, Thames & hundson, 15, 1985.
3. Sorge, R., Udale, J., The Fundamental of Fashion Design, Ava Publishing SA, 8, 2006.
4. chno Textlies, Thames and Huson, 105, 1998.
5. Fletcher, K., Sustainable Fashion & Textiles design Journey, Earthscan, 98, 2008.
Agradecimentos
À empresa portuguesa LMA pela disponibilização dos materiais têxteis utlizados na produção das peças. À professora Maria José Geraldes e ao departamento de ciências e tecnológia têxteis.
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Etiquetas Têxteis com a integração de símbolos para interpretação de cores em padrões pelos Daltónicos
Craveiro, F.
1, Lucas, J. M.
1
1 Unidade dos Materiais Têxteis e Papeleiros, Departamento de Ciência e Tecnologia Têxteis, Universidade da Beira Interior,
Covilhã, Portugal.
Abstract
Colour blindness is the common name attributed to the
congenital change, which prevents the perception of one
or more colours, where people affected by this disorder
simply do not agree with most people about the colours.
Most colour-blind can not distinguish between shades of
red and green when light is low, others do not distinguish
blue from yellow. As such, the colour-blind also feel a
need for autonomy and independence in relation to
fashion trends and choice of clothing.
This way, we intend to make this work a study on the
perception of colour-blinds, their limitations and which
are the main problems to solve in the choice of certain
garments with various patterns.
Thus, this project aims to contribute to all individuals that
can not distinguish certain colours, since there are
different types of colour blindness, and whose main
difficulty is in the clothing, because it is an activity that
requires independence in order to be autonomous in their
choices, either to buy and to combine and wearing
garments mostly with patterns that may difficult choices
of each other
Introdução
O Daltonismo pode não ser considerado uma deficiência,
na medida em que a visão de uma pessoa Daltónica é
considerada normal e consiste numa alteração congénita
que provoca a confusão das cores, mais concretamente na
sua identificação e distinção e ocorre principalmente com
a cor verde e com a cor vermelha, sendo em menor
percentagem aqueles que não identificam o azul e
amarelo, que é designado de Daltonismo dicromático,
uma vez que na retina existem apenas dois cones, que
podem causar algum desconforto ao nível do dia-a-dia, na
execução de determinadas tarefas. Refira se também que
existe o Daltonismo que atinge a percepção de todas as
cores, obtendo apenas uma visão de duas cores,
nomeadamente o preto, o branco e em tons de cinza e é
designado por Daltonismo monocromático. Por último, o
Daltonismo tricromático, sendo o mais comum e em que
os indivíduos possuem os três cones mas que interpretam
as cores de maneira alterada, sendo esta deficiência muito
idêntica à dicromática.
O Daltonismo verifica-se na sua maioria no sexo
masculino (98%) devido ao cromossoma X, porém é de
referir que vêem entre 500 a 800 cores. Apesar de não
haver nenhum tipo de tratamento, existem recursos
ópticos, tais como lentes de contacto que facilitam a
identificação das cores.
O aparecimento do Daltonismo foi no séc. XVIII,
descoberto pelo Inglês John Dalton (1766-1844) sendo ele
próprio Daltónico, que se apercebeu desse distúrbio
quando detectou que não conseguiu distinguir as cores
vermelho e verde. No entanto, o indivíduo que veio
estruturar a teoria acerca do Daltonismo foi o filósofo
Alemão Hermann Von Helmholtz que as complementou
com as explicações científicas do físico inglês Thomas
Young (1801).
Segundo as teorias de Helmholtz e Young, cada cone é
responsável pela percepção de uma determinada região do
espectro luminoso, na medida em que a retina tem três
tipos de cones sensíveis às cores, em que no caso dos
Daltónicos há uma sobreposição de regiões (cores
primárias: vermelho, verde e azul que, quando
combinadas originam as chamadas cores primárias) do
espectro (figura 1) ou seja, consegue-se perceber cada cor
quando os cones são estimulados, isto é, é emitida uma
mensagem ao cérebro quando os cones sensíveis fazem a
leitura de determinada cor.
Figura 1: Espectro das cores (diferentes comprimentos de onda)
Retirado de http://fernandoimperator.wordpress.com/2008/10/06/over-the-rainbow-e-por-que-nao-enxergamos-os-
ultravioletas-e-infra-vermelhos/(em5 Junho 2011).
22
Metodologia do Projecto
Este trabalho foi desenvolvido com base num problema
de Daltonismo, sendo estruturado o tema e os objectivos
do trabalho em causa e a metodologia a seguir. Numa
primeira etapa, partiu-se para a pesquisa de referências
bibliográficas de modo a desenvolver todo o estudo
teórico acerca do Daltonismo, do Sistema Visual, da Cor,
do Design Moda, da Ergonomia do vestuário e por último
das etiquetas têxteis e as suas composições. De seguida
desenvolveu-se a fase experimental das etiquetas têxteis
com a integração de símbolos para identificação de cores
em padrões, recorrendo-se a um questionário distribuído
por uma pequena amostra composta por nove indivíduos
(sete do sexo masculino e dois do sexo feminino) de
modo a elaborar as etiquetas com base nesta amostra e
qual o(s) tipo(s) de Daltonismo que nela vigorava, de
modo a entender quais as cores que na maioria da amostra
não eram perceptíveis na identificação de padrões em
vestuário.
Pretendeu-se também perceber qual o interesse por parte
da amostra em relação às tendências da Moda,
nomeadamente em relação a padrões que podem se tornar
um obstáculo para a conjugação do vestuário e por
conseguinte a compra do mesmo e qual a importância da
cor no vestuário, sendo que o Daltonismo pode ser
considerado uma limitação na integração social e
recorrerem sempre à ajuda de terceiros para a aquisição de
determinado vestuário. Desenvolveu-se a criação das
etiquetas têxteis através dos resultados do questionário e
posteriormente à sua avaliação, elaborando um novo
questionário composto pelas etiquetas modificadas e com
o devido símbolo integrado na cor que não visualizam e
foi distribuído novamente pela mesma amostra de modo a
cada um dar a sua opinião individual acerca da ideia da
criação da etiqueta com a integração de símbolos para a
identificação de cores em determinados padrões para ser
aplicada no vestuário. Por último foi elaborada uma
pequena colecção (três coordenados femininos e três
coordenados masculinos) tendo sido confeccionado dois
coordenados (um feminino e um masculino) onde foi
aplicada a etiqueta têxtil com a respectiva integração dos
símbolos segundo o tipo de Daltonismo que vigorava na
amostra.
Referente ao estudo e pesquisa utilizada na parte teórica,
recorreu-se a um questionário que foi realizado a uma
amostra de indivíduos Daltónicos. A amostra de
inqueridos foi diversificada, não havendo um local
específico para a entrega dos questionários, derivando de
conhecimentos através de colegas. O número total de
questionários foi de nove pessoas (pequena amostra),
sendo o principal objectivo realizar uma etiqueta têxtil
para diversos padrões (tendências actuais) com base na
identificação de cores que estes indivíduos têm
dificuldade em visualizar quando compram determinadas
peças de vestuário e no interesse que têm na sua
conjugação, relacionando Moda e Cor.
Os objectivos principais deste trabalho foram:
Criar uma maior independência na escolha de
vestuário com padrões por parte dos Daltónicos;
Verificar se a criação de etiquetas segundo
determinados padrões com a atribuição de
símbolos ajudam na identificação das cores;
A importância da cor na Moda;
Na análise de dados para a criação da etiqueta têxtil, não
se recorreu a nenhum programa de Estatística,
nomeadamente ao Statistical Package for the Social
Sciences (SPSS) para construir a matriz e proceder ao
tratamento estatístico dos dados, pelo facto de a amostra
ser pequena, não se justificando a sua utilização, devido a
serem dados de fácil tratamento, em que se utilizou o
Microsoft Excel 2010.
No que diz respeito ao estudo, pretende-se saber que tipo
de Daltonismo vigora na amostra de participantes, cujo
número de inquiridos são nove pessoas Daltónicas para a
qual serão desenvolvidas etiquetas têxteis no sentido de
melhorar a qualidade de vida destas pessoas na escolha de
vestuário e criar uma certa independência no que toca à
escolha de determinadas peças de vestuário com padrões e
possíveis combinações, tendo por base um questionário
relacionado com as cores (testes de Daltonismo e questões
relacionados com a Moda, a Cor e as Tendências e com
materiais, onde estão presentes padrões de diferentes
cores e feitios com base em tendências actuais para a
próxima estação Primavera/Verão 2012.
O questionário contém quatro grupos, sendo uma forma
mais exacta para se analisar os resultados e para
diferenciar as categorias das perguntas. A primeira parte
do questionário refere-se à caracterização da amostra
estudada em relação ao curso, género, nível de
escolaridade e as áreas de interesse dos indivíduos.
A segunda parte refere-se à identificação de símbolos
através das cores, segundo os testes de Jean Jouannic,
cujo objectivo seria assinalar a resposta certa consoante as
cores que os indivíduos vêem e segundo os testes de
Ishihara, em que o objectivo seria através de figuras de
círculos pontilhados identificar um número ou um
símbolo.
Um terceiro grupo é formado por um conjunto de
questões abertas (de resposta rápida) acerca da Moda, da
Cor, de Tendências, das suas preferências, do seu nível de
dependência face à escolha do vestuário, bem como a
análise referente ao tipo de Daltonismo de que cada um é
portador.
Numa última parte do questionário, tendo em conta os
tecidos estampados (padrões utilizados para a próxima
estação de Primavera/Verão 2012), foram digitalizadas
oito amostras de tecidos todas com estampados com as
mais diversas formas e cores, de modo a que cada
23
indivíduo ao observar um tecido o descrevesse e
identificasse o respectivo desenho e as respectivas cores
que o constituem.
A criação dos símbolos para aplicação nos tecidos
estampados teve como origem a não passagem por um
processo de aprendizagem rigoroso, daí a atribuição de
símbolos simples como círculos e triângulos, (figura 47)
de forma a facilitar a memorização, criando-se uma escala
de cinco intensidades de cinzentos atribuída a cada cor
existente no padrão, de modo a identificar correctamente
as cores e a sua intensidade.
No seguimento da análise dos questionários, verificou-se
que o tipo de Daltonismo que vigorava na amostra
consiste na deficiência da visualização do verde e do
vermelho (Dicromacia), sendo portanto através dos
resultados obtidos que se realizou a selecção de alguns
tecidos com padrões que contivessem o verde e o
vermelho e também ambas as cores num só padrão, em
que através do Kaledo Print se introduziu a simbologia
conforme a intensidade das cores, criando-se os símbolos
(círculo e triângulo) atribuindo-lhes determinada
intensidade na escala de cinzentos (figura2)
Escala de intensidade do símbolo para identificação da cor vermelha (círculo):
Maior intensidade Menor intensidade
Escala de intensidade do símbolo para identificação da cor verde (triângulo):
Maior intensidade Menor intensidade
Figura 2: Escala de intensidades atribuída aos símbolos para identificação das cores: vermelho (=circulo) e verde
(=triangulo).
No seguimento da análise dos questionários, verificou-se
que o tipo de Daltonismo que vigorava na amostra
consiste na deficiência da visualização do verde e do
vermelho (Dicromacia), sendo portanto através dos
resultados obtidos que se realizou a selecção de alguns
tecidos com padrões que contivessem o verde e o
vermelho e também ambas as cores num só padrão, em
que através do Kaledo Print se introduziu a simbologia
conforme a intensidade das cores, criando-se os símbolos
(círculo e triângulo) atribuindo-lhes determinada
intensidade na escala de cinzentos.
De seguida é feita uma redução de cores das diversas
imagens dos tecidos originais, obtendo uma imagem a
mais parecida possível ao padrão original de maneira a ser
trabalhada para a introdução das diversas intensidades de
símbolos consoante a intensidade da cor pretendida.
Após a redução das cores em relação ao padrão original
obtendo um padrão semelhante, trabalharam-se as cores
sobre as quais iríamos aplicar os símbolos, no caso do
vermelho, fez-se uma separação das várias intensidades
de vermelhos e introduziu-se o símbolo correspondente
(círculo) para cada intensidade desta cor existente no
padrão. Para a cor verde o procedimento foi o mesmo. No
final da aplicação dos símbolos, juntam-se as separações
de todas as outras cores feitas anteriormente, de modo a
construir a imagem inicial quando foi feita a redução de
cores do tecido original, mas com a introdução dos
símbolos no padrão.
Depois de criadas as etiquetas têxteis com os devidos
símbolos (figura 3) e as intensidades conforme as cores do
padrão, foi novamente enviado via correio electrónico um
24
documento em formato pdf com o padrão original e com o
padrão modificado, de modo a obter uma resposta
individual dos inquiridos, com vista a analisar se será uma
boa ajuda a criação de etiquetas com a introdução de
símbolos para identificação de cores em padrões, de modo
a facilitar a compra, a conjugação e a «visualização» das
cores por parte dos indivíduos Daltónicos.
Figura 3: Exemplo das etiquetas com os diversos padrões e com a integração dos símbolos nas respectivas cores (vermelho e
verde) para identificação das mesmas.
Conclusões
A ideia de fazer um estudo acerca do Daltonismo e criar
uma etiqueta têxtil para Daltónicos, surgiu no seguimento
de um projecto realizado em Projecto de Moda (2º ano de
Mestrado Design Moda), cujo objectivo seria resolver ou
pelo menos tentar facilitar a vida de determinadas pessoas
portadores de deficiências, talvez por querer ajudar
pessoas nesse campo da deficiência, pois tem tanto direito
de ter qualidade de vida e dependência no que toca na
escolha de vestuário uma pessoa dita «normal» como o
facto de tentar perceber como é que alguém «não»
consegue ver as mesmas cores que nós, revelando uma
certa confusão.
Apesar de haver um estudo referente aos Daltónicos para
identificar as cores através de símbolos em vestuário do
autor Miguel Neiva, este requer um processo de
aprendizagem exigente, enquanto no caso do meu estudo,
a aprendizagem dos símbolos aplicados na etiqueta para
identificação de determinadas cores, não requer grande
exigência, sendo simplificado, dependendo do tipo de
Daltonismo e consoante o símbolo integrado na cor. No
entanto, é sempre possível de se tornar um processo ainda
mais simplificado na junção dos símbolos da Dissertação
de Miguel Neiva ou outros já elaborados e introduzi-los
nos padrões, de maneira a evitar a aprendizagem de novos
símbolos.
.
Referências bibliográficas
1. ALLAN, Alvaro Jr Santos; Atendimento Educacional
Especializado; DEFICIENCIA VISUAL; Elizabet
Dias de Sá, Izilda Maria de Campos, Myriam Beatriz
Campolina Silva, Editora AllanAlvaroJr Santos.
2. ARNHEIM, Rudolf; ARTE E PERCEPÇÃO VISUAL- UMA PSICOLOGIA DA VISÃO CRIADORA; Thomson Pioneira; 1ª Edição; 1998.
3. BARNARD, Malcolm, FASHION AS COMUNICATION, New York, USA: Routledge,
2007.
4. BARTHES, R. THE DISEASES OF COSTUME,
Partisian Review, 1967.
5. BERLIM, B. & KAY, P.; BASIC COLOR TERMS: THEIR UNIVERSALITY AND EVOLUTION;
Berkeley: University of California Press; 1969.
6. BONSIEPE, Gui; TEORIA E PRÁTICA DO DESIGN INDUSTRIAL: ELEMENTOS PARA UM MANUAL CRÍTICO; Centro Português de
Design; Lisboa; 1992.
7. FLUGEL; PSICOLOGIA DO VESTIR; Assírio e
Alvim; 1989.
8. GRAGNATO, Luciana, Dissertação de Mestrado; O DESENHO NO DESIGN MODA; Universidade
Anhembi Morumbi, São Paulo; 2008
25
Contribution to the Structural Characterization of Poly(vinyl alcohol) PVA Nano Structured Polymeric Materials
using a 3D Computational Simulation Model
J.M.R. Curto1, E.L.T. Conceição2, P.A.F. Rodrigues1, N.J.R. Belino1, A.T.G. Portugal2, R.M.S. Simões1, M.J. Santos. Silva1 1University of Beira Interior, Textile and Paper Materials Research Unit Covilhã,
Portugal.
2 University of Coimbra, Chemical Engineering Dep., Pólo II, Rua Sílvio Lima Coimbra. Portugal
Abstract
Nanoscale materials can be rationally designed to exhibit novel and significantly improved physical, chemical, and biological properties, phenomena, and processes because of their size. They are of interests in a wide variety of applications including semi-permeable membranes, nanocomposites, filters, protection clothing and biomedical applications such as wound dressings, tissue engineering, scaffolds and drug delivery systems.
The purpose of this article is to present an innovating 3D nano structured polymeric material model and to use it to characterize Poly(vinyl alcohol) structures obtained by electrospinning. The three dimensional model was developed to include fibre and web structural properties. A computational simulator was developed from scratch, using MATLAB, and was used to perform simulation studies. Poly(vinyl alcohol) nanowebs were produced by electrospinning. SEM photographys were used investigate the range of variation of fibre dimensions and the structure thickness was evalueted using a micrometer. Simulation studies were done to study the influence of fibre dimensions and fibre flexebility, using a Lattin square design for computational experiments. The resulting data was treated using regression trees and the relative importance of fiber properties on structural web properties was established. The simulated PVA nanoweb structures were characterized in terms of porosity, thickness, coverage and Relative Bonded Area with a resolution of 5 nm.
Introduction Poly(vinyl alcohol), PVA is a water-soluble polyhydroxy polymer (figure 1) with excellent chemical resistance, physical properties, and complete biodegradability that have led to to a broad use of practical applications [1].
PVA has been used in fiber and film products, paper coating, adhesives and as a colloid stabilizer. In recent years, much attention has been focused on the biomedical applications of PVA hydrogels and nanofibrous materials, including contact lenses, artificial organs and drug delivery systems [2-5].
Figure 1 Monomer and PVA polymer chemical representation
Electrospinning is a process that produces continuous polymer fibers with nanoscale diameters through the action of an external electric field imposed on a polymer solution [6].
26
Electrospinning is a polymer processing technology that allows generation of fibers (from nanometer to micrometersize) to form randomly deposited nonwoven electrospun fiber structures that have a larger specific surface area and small pore size compared to other nonwoven fabrics [7]
The morphology of fibers depends on the process parameters with typical fiber diameters in the range 10nm- ].
Circular cross fibre sections are typically produced, although under certain conditions, other geometries such as tube and collapsed ribbon like structures have been reported [9].
In spite of the increasing importance of nanomaterials and the difficulty to measure structural properties in the nano scale there is a lack of information about nanowebs modeling and simulation. The first approach for modeling disordered fibrous materials is done by Kallmes and Corte with the goal of simulating fibrous structures like paper [10]. In their statistical geometry approach the random fiber network is formed considering that the location of any given fiber is independent and each fiber has equal probability of making all possible angles with any arbitrarily chosen axis. For materials such as paper, non-woven textiles, or fibrous filters, fibers have finite length, so fiber centers are assumed to be distributed according to a point Poisson process in the plane. For electro spun networks, fibres can be assumed to have infinite length [11]. Such networks can be modeled as a random network of infinite lines that represent the longitudinal axes of fibres and pass through points distributed according to a point Poisson process in the plane, with uniformly distributed orientation [12]. Researchers like Sampson and Dodson have considered an idealized two dimensional random network when modeling network structure [13, 14]. In 1998 Wang and Shaler [15] proposed a three dimensional structure made from rigid cylindrical fibres. The major breakthrough came with the introduction of the fibre flexibility in the work of Niskanen, Alava and coworkers [16-18]. This model is called KCL-PAKKA. Departing from this model but including fibre transversal morphology and an innovative implementations, a three dimensional structure simulator was formed and validated by Conceição et al and Curto et al. [18, 19].
The simulation model was adapted to simulate nano fibrous materials and implemented using MATLAB.
Materials and Methods A PVA solution was prepared from PVA powder (99% hidrolized, Mw 89.000 98.000) from Sigma Aldrich and distilled water at 70 °C with stirring during 1h. The concentration of the PVA solution was 10 wt %. The PVA solution was placed in a 10ml syringe. The flow was controled at 0.1 mL/min (Harvard Apparatus PHD 200 Pump). The structure was colected in to na aluminum foil. The power supply voltage was 30 kV, and the tip-tocollector distance (TCD) was 12 cm. Figure 2 is photography of the electrospinning prototype at University of Beira Interior.
Figure 2- Electrospinning prototype
The collected strucutures were dryed in a temperature and humidity controled room (ISO standard).
The nano fibrous materials simulation model was developed using MATLAB, from MathWorks, which is a numeric computation environment and programming language. The Micrometer standard NP EN 205 34-1994 was used to determine the structure thickness.
SEM photographs were obtained on UBI Optical Center.
Tthe design of computer experiments was done using a space filling design, namely the Latin hypercube sampling design [20, 21].
Decision trees were used to classify the computational simulations results and determine the relative influence of fibre properties on the final web properties [22].
27
Results and discussion
Comparing the SEM photography of the PVA electrospun fibrous network and the structure obtained by computational simulation, the similarity is notorious (Figures 3 and 4).
Figure 3 Poly(vinyl alcohol) SEM photograpy
Figure 4 - Simulated PVA structure
To study the influence of different factors like, fiber dimension, fiber flexibility, lattice dimensions (Nxy), a design of computer experiments was done using a space filling design, namely the Latin hypercube sampling design [23, 24].
SEM photographs were used to obtain information about fiber dimensions and coverage.
The simulation results were organized using decision trees, provided by the function ctree, in the R package party, using the default settings. The number of simulations chosen was 1000. A range for the input parameters was defined based on experimental SEM information and preliminary simulation studies. Several web properties were accessed: thickness, porosity, relative bonded area, and coverage but only an example for the thickness is presented here.
Figure 5 presents the decision tree for nanoweb thickness is. The first split occurs at fiber flexibility, indicating that it is the most important fiber properties when defining PVA thickness.
Figure 5 - Decision tree for PVA nanowebs thickness. Number of simulations = 1000.
The central idea behind building a decision tree consists of a binary split of the data made according to the value of the single most appropriate predicting variable, so that the observations on each of the two resulting subsets are as similar as possible regarding the response variable of interest. Starting from the root node containing the entire original data, a test is constructed to divide up the data into two mutually exclusive groups, said to be the children nodes, of that parent node. Then the observations that meet one of the conditions follow one branch, for example the left branch, while the others go to the right branch. Next, each child node is split using the same process, and this procedure is repeated downwards in a recursive manner until some termination condition is satisfied. A terminal node which is not subdivided any further is called a leaf node.
28
Conclusions
In this paper a new computational model is used to simulate the structure of a random fibrous Poly(vinil alcohol) material obtained by electro spinning. The 3D PVA nanofibrous simulated structures are characterized (porosity, thickness, RBA, coverage) with a resolution of 5 nm. References [1] Zhang, C., Yuan, X., Wu, L., Han, Y. and Sheng, J.. Study on morphology of electrospun Poly(vinyl alcohol)
mats . European Polymer Journal 41, 2005, pp. 423 432. [2] Li, W. J., Laurencin, C. T., Caterson, E. J., Tuan, R. S. and Ko, F. K. Electrospun nanofibrous structure: a novel scaffhold for tissue engineering . Journal of Biomedicine Material Research, Part A, 60(4), 2002, pp. 613 621. [3] Nakane, K., Yamashita, T., Iwakura, K. and Suzuki, F. Properties and structure of poly(vinyl alcohol)/silica
composites. Journal of Applied Polymer Sciences , 74(1), 1999, pp. 133 138. [4] Jayaraman, K. et al., Recent advances in polymer
, J. Nanosci. Nanotechol. 4, 2004, pp. 52-65. [5] Baker, M.I, Walsh, S.P., Schwartz, Z. and Boyan,
(vinyl alcohol) and its uses in cartilage and orthopedic applications. J Biomed Mater Res B Appl Biomater, Jul;100(5), 2012, pp.1451-7. [6] Rutledge, G.C. and Fridrikh, S.V, Formation of fibers by electrospinning, Adv. Drug Del. Rev., 59, 2007, pp. 1384-1391. [7]
ci. Nanotechol. 4, 2004, pp. 52-65. [8] Fridrikh, S.V. et al., Controlling the fiber diameter during electrospinning, Phys. Rev. Lett., 90, 2003, pp. 1-4. [9]
Sci., B39, 201, pp. 2598-2606.
[10] Kallmes, O. and Corte, H., Tappi J., 43(9), 1960, pp. 737.
[11geometry of pores and statistics of porous nanofibrous
-318.
[12
[13] Dodson, C. and Sampson, W., J. Statist. Phys., 96 1999, pp. 447.
[14] Sampson, W. Proc. 12th FRS, Oxford, 2001, pp. 1205-1288.
[15] Wang, H. and Shaler, S., J. Pulp Pap. Sci., 24(10) 1998, pp. 314.
[16] Niskanen, K. and Alava, M., Phys. Rev. Lett., 73(25), 1994, pp. 3475.
[17] Alava, M. and Niskanen, K., Reports on Progress in Physics, 69(3), 2006, pp. 669.
[18] Conceição, E., Curto, J., Simões, R. and Portugal, A. Coding a simulation model of the 3D structure of paper .
In Proceedings of the 2nd International Symposium on Computational Modeling of Objects represented in Images, CompIMAGE 2010, USA. Lecture Notes in Computer Science, Barneva; R.P. et al. (Eds.), Springer-Verlag Berlin, vol.60 no.26, 2010, pp. 299 310. ISBN: 978-3-642-12711-3. ISI Document Delivery No.: BPJ99.
[19] Curto, J., Conceição, E., Portugal, A., Simões, R., Three dimensional modeling of fibrous materials and
experimental validation. Materialwissenschaft und Werstofftechnik, Materials Science and Engineering Technology, Wiley-vch, Germany, Wiley-Blackwell, USA, vol.42 no.5 (2011): pp. 370-374. ISSN: 0933-5137 (Print). ISSN 1521-4052 (Online). ISI Accession Number: CCC: 000290455700006.
[20
statistics, Springer-Verlag, New York, USA, 2003.
[21] Fang, K.-modelling for computer experimentsand data analysis series, Chapman & Hall/CRC, London, UK, 2005.
[22] Breiman, L., Friedman, J. H., Olshen, R. A., Stone, C. J., Classification and Regression Trees, Wadsworth, Belmont, CA, 1984
Acknowledgements
Optical Centre, University of Beira Interior.
29
Sistema para análise da formação da folha de papel por retrodifusão e transmissão da radiação laser
A. O. Mendes1, P. T. Fiadeiro1,2, M. V. Bernardo1, A. P. Costa2, M. E. Amaral2, M. N. Belgacem3
1Unidade de Deteção Remota, Universidade da Beira Interior, 6201-001 Covilhã, Portugal 2Unidade de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, 6201-001 Covilhã, Portugal
3Grenoble INP – Pagora, Ecole internationale du papier, de la communication imprimée et des biomatériaux, 38402 Saint Martin d’Hères Cedex, France
Resumo
Neste trabalho é apresentado e descrito um sistema ótico experimental, desenvolvido e implementado no Centro de Ótica da Universidade da Beira Interior, para caracterização da formação da folha de papel por retrodifusão e transmissão da radiação laser. Em particular, este sistema baseia-se num outro sistema ótico anteriormente desenvolvido pelo nosso grupo de investigação para o mesmo efeito. Em termos gerais, o atual sistema corresponde a uma versão mais complexa do sistema original, tendo sido especialmente concebido e desenhado de modo a permitir avaliar, simultaneamente e na mesma região, a densidade de massa e a orientação da distribuição das fibras nas duas superfícies e na espessura da folha de papel, de uma forma mais fiável e sustentada.
Introdução
O conhecimento da estrutura da folha de papel, em termos da orientação da distribuição das fibras de celulose que o compõem, assim como da forma como essas mesmas fibras estão depositadas ao longo da espessura da folha de papel, é uma questão importante e que sempre interessou o sector da indústria do papel.
Dada a importância desta temática, muito trabalho tem sido realizado por vários grupos de investigação para a avaliação e caracterização da formação da folha de papel [1-12]. O nosso grupo de investigação não é exceção e, como tal, também se tem dedicado ao estudo desta temática, tendo adquirido, nos últimos anos, experiência e conhecimento neste campo em particular [13-17]. A investigação realizada pelo nosso grupo nesta matéria centrou-se no desenvolvimento e implementação de sistemas e metodologias óticas para avaliação de diversos parâmetros papeleiros. Uma dessas metodologias baseou-se na produção de réplicas das superfícies de folhas de papel e na sua análise por difração da luz laser, permitindo determinar a anisotropia e a orientação da distribuição das fibras nas superfícies do papel [13-15]. Uma outra metodologia, também desenvolvida pelo nosso grupo, baseou-se na difusão da luz na estrutura interna do papel, utilizando amostras reais de papel em vez de réplicas como no caso anterior, com o intuito de se
determinar a anisotropia e a orientação da distribuição das fibras do papel na sua espessura [16].
Posteriormente, foi implementada uma outra metodologia que procurava ser mais abrangente e completa do que as duas metodologias anteriormente referidas. Esta metodologia assentava na análise da orientação da distribuição das fibras à superfície e na espessura do papel, assim como da densidade de massa em simultâneo e na mesma região do papel, sem se recorrer à produção e uso de réplicas das folhas de papel. Especificamente, este sistema utilizava a luz laser retro refletida a partir de cada uma das faces da folha de papel, para a análise na superfície (orientação da distribuição das fibras) e a luz laser transmitida através da folha de papel para análise no seu volume (orientação da distribuição das fibras e densidade de massa) [17]. No entanto, como este sistema utilizava o feixe proveniente de um único laser para iluminar as amostras de papel, a análise de ambas as faces do papel não era feita em simultâneo. Existia simultaneidade nas medições efetuadas para cada uma das faces do papel isoladamente mas não entre faces. Para além disso, a análise efetuada na mesma região de ambas as faces também não era garantida. Devido ao uso de um único laser no sistema para iluminar as amostras, o procedimento experimental adotado tinha forçosamente de contemplar a análise das faces do papel em duas etapas. Primeiramente, com este sistema era analisada uma das faces do papel, à superfície e através da sua espessura. De seguida, era necessário retirar a folha de papel do suporte, reverter a folha e reposicioná-la no suporte garantindo-se, dentro do possível, que esta permaneceria na mesma posição por forma a analisar a outra face do papel, igualmente à superfície e na sua espessura. Contudo, este procedimento experimental não se mostrou viável na prática, por ser extremamente complicado, senão mesmo impossível, garantir o correto reposicionamento da folha de papel no suporte. No entanto, apesar destas desvantagens, a implementação deste primeiro sistema revelou ser de grande utilidade e importância, pois serviu de base para a realização de diversos testes e ensaios preliminares, servindo igualmente como prova de conceito e de funcionamento do método.
Face ao exposto e com vista a fornecer um contributo positivo à indústria papeleira no que se refere a caracterização da formação da folha de papel, foi
30
redefinida a montagem do sistema ótico original. Assim, foi desenvolvido e implementado, no Centro de Ótica da Universidade da Beira Interior, um novo sistema ótico experimental mais complexo para se poder estudar a orientação da distribuição das fibras, à superfície e na espessura, e a densidade de massa de amostras de papel através da retrodifusão e da transmissão da radiação laser sem ter de se manusear as amostras de papel. Desta forma, o novo sistema desenvolvido permite analisar os vários parâmetros em estudo de uma forma mais fiável e sustentada, com análises efetuadas em simultâneo e exatamente na mesma região de ambas as faces das amostras de papel.
Material e Métodos
O sistema ótico experimental desenvolvido e implementado pela nossa equipa de investigação para a caracterização da formação da folha de papel consiste num sistema de não-contacto que executa o varrimento de amostras de papel ao mesmo tempo que adquire imagens da radiação laser retro difundida e transmitida em cada uma das faces do papel. Na Figura 1 é mostrado o aspeto geral do sistema ótico experimental desenvolvido, sendo visíveis os principais elementos que compõem o sistema. Em particular, pode observar-se na figura que o sistema corresponde na realidade a um sistema duplo, com dois ramos equivalentes que podem funcionar de forma isolada ou conjuntamente. Também é visível nesta figura que o sistema apresenta uma configuração simétrica dos dois ramos em relação ao suporte da amostra de papel, que se encontra acoplada ao sistema de varrimento motorizado de dois eixos.
Figura 1 – Aspeto geral do sistema ótico experimental desenvolvido para caracterização da formação da folha de papel por retrodifusão e transmissão da radiação laser.
De notar ainda, na zona central da imagem mostrada na Figura 1, junto à amostra de papel, que são visíveis duas lentes objetivas utilizadas para focagem, sendo também responsáveis pela resolução espacial do sistema,
estabelecida de modo a permitir uma análise à escala microscópica.
Em termos de procedimento experimental, basicamente, o sistema funciona iluminando uma mesma região da amostra de papel, por lados opostos, utilizando os feixes provenientes dos dois lasers (ver Figura 1). Após ser garantido o correto alinhamento dos dois feixes entre si, o feixe proveniente do laser 1 (localizado no lado esquerdo do sistema) ilumina a amostra enquanto que o feixe proveniente do laser 2 (localizado no lado direito do sistema) é obstruído, o que resulta na iluminação da amostra de papel apenas pelo lado esquerdo (face A). Nestas condições, o detetor de imagem 1 (localizado no lado esquerdo do sistema) irá registar a radiação do laser 1 retro difundida pela face A e o detetor de imagem 2 (localizado no lado direito do sistema) irá registar a radiação do laser 1 transmitida ao longo da espessura do papel partindo da face A.
Seguidamente, o feixe proveniente do laser 1 é agora obstruído enquanto que o feixe proveniente do laser 2 é desobstruído para iluminar a amostra, o que se traduz na iluminação da amostra de papel apenas pelo lado direito (face B). Nestas condições, o detetor de imagem 2 irá agora registar a radiação do laser 2 retro difundida pela face B e o detetor de imagem 1 irá registar a radiação do laser 2 transmitida ao longo da espessura do papel partindo da face B.
Nas Figuras 2 e 3 são mostradas, respetivamente, imagens das faces A e B de uma amostra de papel evidenciando-se a região do papel em análise e que corresponde à mancha de luz laser visível nas figuras.
Figura 2 – Imagem da face A da amostra de papel evidenciando-se a região do papel em análise, iluminada pelo feixe proveniente do laser 1 (retrodifusão).
31
Figura 3 – Imagem da face B da amostra de papel evidenciando-se a mesma região do papel em análise, iluminada pelo feixe proveniente do laser 1 (transmissão).
Para a região considerada, são então registadas quatro imagens distintas sendo que duas delas correspondem a imagens capturadas por retrodifusão (análise de superfície), e as restantes duas correspondem a imagens capturadas por transmissão (análise na espessura). Em particular, as imagens obtidas por retrodifusão vão permitir analisar a orientação da distribuição das fibras nas duas superfícies do papel (faces A e B) enquanto que as imagens obtidas por transmissão vão permitir analisar a orientação da distribuição das fibras na espessura do papel (considerando ambas as faces e a sua estrutura interna) e também a densidade de massa do papel.
Após aquisição e armazenamento das quatro imagens, o processo é repetido para a região seguinte da amostra, usando-se um passo definido. Para isso, é necessário deslocar a amostra de papel em relação aos dois feixes laser de modo a que seja executado o varrimento completo das amostras. O processo de deslocamento das amostras de papel é automático e é efetuado através de um sistema motorizado de dois eixos, que executa movimentos das amostras ao longo de ambas as direções horizontal e vertical. Este sistema permite assim a realização de um procedimento de varrimento “ponto-a-ponto” completamente controlado ao longo de toda a extensão das amostras de papel.
Uma das principais características e vantagens deste sistema, em relação ao sistema desenvolvido originalmente, reside no facto das medições da orientação da distribuição das fibras e da densidade de massa das folhas de papel serem efetuadas em simultâneo e exatamente na mesma região de ambas as faces do papel, o que resulta numa total correspondência “ponto-a-ponto” associada aos parâmetros em estudo.
Por fim, através da combinação de todos os dados obtidos, a caracterização da formação da folha de papel é alcançada para cada uma das regiões analisadas nas amostras de papel, permitindo a avaliação da orientação
da distribuição das fibras e a densidade de massa do papel, tanto localmente como em termos globais.
Conclusões
Este trabalho foi dedicado à apresentação e descrição de um sistema ótico experimental, desenvolvido e implementado no Centro de Ótica da Universidade da Beira Interior, para caracterização da formação da folha de papel. O sistema foi baseado no sistema desenvolvido originalmente para o mesmo efeito, correspondendo este novo sistema a uma versão mais complexa do sistema original. Embora a montagem do sistema tenha sido redefinida e algumas alterações tenham sido efetuadas por motivos diversos (otimização do espaço físico, otimização das condições de iluminação, eliminação de ruído, entre outros), na sua essência, o sistema funciona exatamente da mesma maneira que o sistema original. No entanto, esta nova versão do sistema foi especialmente concebida e desenhada de modo a permitir a avaliação da orientação da distribuição das fibras, à superfície e na espessura, e a densidade de massa da folha de papel, sem ter de se manusear as amostras de papel, sendo assim efetuada em simultâneo e exatamente na mesma região de ambas as faces do papel. Desta forma, são vencidas as principais desvantagens associadas à montagem original do sistema, o que se traduz numa forma mais fiável e sustentada de caracterizar a formação da folha de papel.
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[15] M. J. T. Pereira, P. T. Fiadeiro, and J. Silvy, "Paper surface diffraction to characterise the fibre orientation distribution," presented at Proceedings of SPIE Vol. 4448 - Optical Diagnostics for Fluids, Solids, and Combustion, 2001.
[16] M. J. T. Pereira, "Diffusion of the Laser Radiation to Characterise the Paper Fibre Orientation and the Paper Sheet Formation," presented at Proceedings of Engenharia‘2005 - Inovação e Desenvolvimento, ENG-05-04-03, 2005.
[17] M. J. T. Pereira, A. P. Costa, P. T. Fiadeiro, J. Silvy, and A. P. Gomes, "Caracterização de Materiais Fibrosos por Métodos Ópticos - OE18," presented at FÍSICA 2005 - Física para o Séc. XXI, 2005.
Agradecimentos
Os autores agradecem o financiamento deste trabalho, efetuado por Fundos FEDER através do Programa Operacional Fatores de Competitividade – COMPETE e por Fundos Nacionais através da FCT – Fundação para a Ciência e a Tecnologia no âmbito do projeto PTDC/CTM-BPC/109770/2009 (FCOMP-01-0124-FEDER-014538).
Os autores agradecem igualmente todo o apoio concedido pela Unidade de Deteção Remota, pela Unidade de Materiais Têxteis e Papeleiros, pelo Centro de Ótica, pelo Departamento de Física e pelo Departamento de Química da Universidade da Beira Interior.
33
Anaerobic treatment of olive mill wastewater: profile of sugars, organic acids and phenolic compounds
L. R. Fernandes, A. Gomes, A. Lopes, R. M. Simões
Unidade de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, Covilhã, Portugal
Abstract
Wastewater from a three phases olive mill in Castelo Branco (Portugal) was characterised and the concentration of sugars, organic acids, COD, phenolic compounds and the biogas production were followed along the anaerobic treatment. The experiments were carried out with a 1:45 dilution ratio and only alkali was added to the effluent. A 60% COD removal and a production of 0.4 0.53ml of gas/mg of charged COD was achieved after 30 days of treatment. The methane content of the biogas was close to 65%.
Introduction In Mediterranean countries, the olive oil industry is very important, in both economic and tradition terms [1]. In resume, the process is based on the olive oil extraction by using a two or a three-phases centrifugation system, after mechanical grinding of the olives. The process results in the worldwide production of more than 30 millions m3 per year of black olive mill wastewater (OMW) [2]. The physicochemical properties of the OMW depends on factors such as method of extraction, type and maturity of olives, region or origin, climactic conditions and associated cultivation/processing methods [3]. Beside its high amounts of organic content (Chemical Oxygen Demand (COD): 37000-318000 mg L-1, total suspended solids (TSS): 6000-69000 mg L-1) [4-6], OMW contains high concentrations of recalcitrant compounds such as lignin and tannins (52270-180000 mg L-1) which confer the dark color to the effluent. In addition, it contains phenolic compounds (500-24000 mg L-1) and long chain fatty acids which are toxics to microorganisms and plants [7, 8]. These effluent properties make its treatment very difficult and several physicochemical and biological treatments, as well as their combinations, have been proposed. Anaerobic digestion has been reported as one of the most promising technologies for the disposal of OMW [3, 10]. Several anaerobic treatments systems have been suggested and used for OMW. Anaerobic treatment of OMW has a number of advantages over aerobic treatment. These include no aeration requirements, lower sludge production, lower nutrient requirements, the production of methane gas as a valuable end product, reduction of greenhouse gases emissions, production of a liquid fertilizer and the quick recovery of anaerobic systems that have been dormant for a long time [9,10,11]. However, several OMW characteristics such as the acid pH, low alkalinity, low nitrogen content and the presence
of a lipidic fraction and phenolic compounds make this wastewater a potential toxic substrate and not suitable for anaerobiosis [10,11]. One approach to the problem has been to sufficiently dilute the OMW to reduce the concentration of phenolic compounds and fatty acids [3,12, 13]. The objective of the present paper is to study the biogas production potential, sugar utilization, organic acid production and consumption during anaerobic treatment at low COD concentrations of OMWs originating from Castelo Branco region. Materials and Methods Olive mill wastewater OMW was obtained from an olive oil plant (three-phases process) located at Castelo Branco (Portugal). Immediately after sampling, the raw OMW was filtered in a 200 mesh screen and maintained at -18ºC during the experimentation period. Analytical methods
Several parameters were used to monitor the effluent and the performance of the treatment process. Total solids (TS), total suspended solids (TSS), total chemical oxygen demand (COD) and lipids were determined as proposed by Standard Methods [14]. Sugars and organic acids concentrations were determined in a Perkin Elmer liquid chromatography system, equipped with a Hewlett-Packard HP 1047A RI detector, using an Aminex HPX-87H column. Sugars and organic acids standards were used for identification; calibration was also carried out for the most important sugars and organic acids. pH was measured using a 794 Basic Titrino (Metrhom AG). Total phenols were determined by Folin-colorimetric method [15].
Anaerobic biotreatment
The bioreactors, operated in batch mode, consisted in 300 ml Schott-Duran bottles with two septums. Each bottle was partially filled with OMW, a predetermined amount of anaerobic sludge, and test medium (in accordance with OECD 311 [16]) to obtain a final volume of 270 ml. The initial concentrations were 6000 mg/L of volatile suspended solids and close to 3000 mg/L of COD. The pH of the initial suspension was adjusted to 7.0 ±0.2 with NaOH 2M and the botto remove any trace of oxygen. The anaerobic sludge was kindly provided by a Portuguese pulp mill, and was maintained in lab with molasses sugar.
34
Finally the test bottles were incubated during 30 days at the temperature of 37±1 ºC. Daily, the gas produced in each bottle was measured and a liquid sample was collected. Blank bottles containing test medium, distilled water and anaerobic sludge run in parallel to determinate the background gas production. A perfectly leakproof reactor (jacketed) with a total volume of 1.2 L was also used to monitor the performance of the anaerobic process, using the same reaction conditions and 1L of initial suspension. The gas production was measured daily, using a syringe. The methane content of the biogas was estimated by bubbling the gas through a NaOH 2M solution. In opposition with the flasks, in this case the suspension was subjected to a very gentle magnetic stirring.
Results and Discussion
OMW composition
The composition of the 200 mesh filtered olive mill wastewater (OMW) is resumed in Table 1. The main feature of the effluent is its very high organic load (total COD value) and the total phenolic compound content. These compounds are usually referred as inhibitor of some microorganisms. Table 1- Composition of OMW
Total solids, (TS) (g/L) 105
Total suspended solids, TSS (g/L) 32
Total dissolved solids, TSS (g/L)) 73
Total COD (g/L) 127
Total phenols (g/L, as galic acid) 6.5
Lipids (g/L) 0.77
pH 5.4
Effect of OMW initial COD concentration on biogas production potential
A preliminary study was carried out during 80 days with the same working volumes (270 mL) but with different initial COD concentrations of: 1000, 2000, 5000, 10000 and 20000 mg of COD/L, to evaluate appropriated conditions to carry out the assays without the addition of nutrients. The results for the biogas specific production (biogas produced/COD charged) after 80 days point to a maximum in the range of 2000 5000 mg/L of initial COD concentration. Higher COD values tend to inhibit the biomass activity and the biogas production is extremely small for an initial COD concentration of 20 g/L. Ergüder et al. (2000) have reported different behavior, which will deserve our future attention. Based
on our results, the initial COD concentration of 3000 mg/L was selected for the following work.
Effect of anaerobic treatment on COD and phenolic compounds
OMW was diluted until a COD of 3000 mg/L and treated in anaerobic reactors at 37ºC and pH 7.2. Daily gas production in each reactor was monitored during 30 days. The results of the experiment are represented in fig 1. These results correspond to the minimum efficiency for this effluent once anaerobic microorganisms used were not previously acclimatized to OMW. Maximum COD and phenolic compound removal efficiency were obtained in the first 3 days of incubation, and after the first 5 days 45% of the initial COD and 43% of the phenolic compounds were already been removed, reaching a maximum removal of 60% after 15 days of treatment for the COD concentration, and 60% of the phenolic compounds after 20 days. In addition, the liquid chromatography results (not shown), obtained with a C18 column and a UV-Vis diode array detector, clearly indicate the global decrease of the phenolic compounds, including tannic acid.
Figure 1 - Effect of reaction time on COD concentration.
Figure 2 - Effect of reaction time on phenolic compounds concentration (Folin-Ciocalteu method).
0
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CO
D (
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lic a
cid/
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35
Effect of anaerobic treatment on sugar and organic acids concentration
Fig 3 and 4 present illustrative chromatogram with the different sugars and organic acids for 0, 3, 10 and 19 days of treatment; fig. 5 shows the time profile of the detected sugar and organic acids in the reaction medium for the experiments with bottles. At the beginning only citric acid, glucose and xylose are present in the reaction medium; three days later, almost all these compounds had been metabolized, and three organic acids are produced and present in the medium in significant amounts (acetic, propionic and butanoic acids). After 10 days of treatment the concentration of these acids was markedly reduced but some acids are still present in the medium. After 19 days of reaction only an unidentified acid remains in the reaction medium.
Figure 3 Sugars and organic acids content at the start and after 3 days of reaction time.
Figure 4 Sugars and organic acids content after 10 and 19 days of reaction time.
Figure 5 Sugars and organic acids concentration time profile, for the bottles.
Biogas time profile
Thirty two test bottles and 1L batch reactor containing the same amount of OMW, test medium and the same pH were incubated at 37ºC and their biogas production was measured daily. Fig. 6 presents these results for the bottles. Similar results were obtained with the batch reactor working with 1 L suspension and with a gentle magnetic agitation. During the first 6 days the daily production of biogas kept up almost constant at about 30 ml bottle/day, then started to decrease in accordance with the sugar and organic acids concentration (Fig. 5).
Figure 7 presents the accumulate biogas production for the bottles, where we can see that after 30 days close to 410 mL of biogas was recovered from the 270 mL of the reaction medium initially charged with a COD concentration of close to 3 g/L. The methane/biogas ratio varied in the range 65 75%. The global biogas production was close to 0.53 mL and 0.88 mL per mg of COD charged and converted, respectively. The methane production is around 0.57 mL per mg of COD converted. For the 1.2 L reactor, these values are close to 20% lower. In general, however, these values compare very well with those previously reported by other authors.
Figure 6 Daily biogas production profile.
Figure 7 Accumulated biogas production profile.
0
100
200
300
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500
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mg
/L
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Citric
Glucose
Xylose
Acetic
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Unknown
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ml/d
ay
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050
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36
Conclusions
OMW has an extremely high organic load and high content of phenolic compounds which anticipates difficulties in its treatment by biological means, particularly by anaerobic microorganisms that are more affected by the high phenols concentration.
In accordance with the high phenolic content of the effluent, we realized that specific gas production decline markedly for COD concentrations higher than 5000 mg/L. In consequence of this, the experiments were carried out at 3 g/L of COD initial concentration. The results indicated that the COD removal can reach 60% with a specific gas production between 0.40 and 0.53 mL per mg of charged COB. The monitoring of the sugars and organic acids has revealed additional information about the complex biochemical reaction involved in the anaerobic effluent treatment. References 1. Roig, A., Cayuela, M.L., Sánchez-Monedero, M.A.,
An overview on olive mill wastes and their valorisation methods. Waste Management 26 (***), 960 969.
2. ., Shannakb B., Al-Shannaga M., Al-Anbera Z. and Al-Hasanc M., Treatment of olive mill wastewater by combined advanced oxidation and biodegradation. Sep Purif Technol 70:141 146 (2009).
3. Panagiota P., Diamadopoulos E., Technologies for olive mill wastewater (OMW) treatment: a review J.Chem Technol. Biotechnol , 81:1475-1485-2006.
4. E. Bettazzi, M. Morelli, S. Caffaz, C. Caretti, E. Azzari, C. Lubello, Olive mill wastewater treatment: an experimental study, Water Science and Technology 54 (8) (2006) 17 25.
5. S. Crognale, A. D'Annibale, F. Federici, M. Fenice, D. Quaratino, D.M. Petruccioli, Olive oil mill wastewater valorisation by fungi, Journal of Chemical Technology and Biotechnology 81 (2006) 1547 1555
6. A. Robles, R. Lucas, G.A. Cienfuegos, A. Galvez,
wastewaters from the olive oil industry by strains of penicillium isolated from wastewater disposal ponds, Bioresource Technology 74 (2000) 217 221
7. Paixao SM, Mendonca E, Picado A and Anselmo AM, Acute toxicity evaluation of olive mill wastewaters: a comparative study of three aquatic organisms. Environ Toxicol 4:263 269 (1999).
8. Rouvalis A, Iliopoulou-Georgoudaki J and Lyberatos G, Application of two microbiotests for acute toxicity evaluation of olive mill wastewaters. Fresenius Environ Bull 13:458 464 (2004).
9. Ammary B Y, Treatment of olive mill wastewater using an anaerobic sequencing batch reactor , Desalination 177 (2005) 157 165
10. Ergüder T.H, Güven E, Demirer G.N. Anaerobic treatment of olive mill wastes in batch reactors, Process Biochemistry 36 (2000) 243 248
11. Sampaio M.A, Gonçalves M.R, Marques I.P, Anaerobic digestion challenge of raw olive mill wastewater, Bioresource Technology 102 (2011) 10810 10818.
12. Hamdi M,Garcia J.L, Ellouz R, Integrated biological process for olive mill wastewater treatment Bioprocess Engineering 8 (1992) 79-84
13. Blika P. S, Stamatelatou K, Kornaros M, Liberatos G, Anaerobic digestion of olive mill wastewater, Global NEST Journal, Vol 11, No 3, pp 364-372, 2009.
14. Standard methods for the examination of water and wastewater. 20 ed. Washington: APHA, 1998
15. Mcdonald, S.; Prenzler, P. D.; Antholovic, M.; Robards, K. Phenolic content and antioxidant activity of olive extracts 2001 73-84
16. Anaerobic Biodegradability of Organic Compounds in Digested Sludge By Measurement of Gas Production, OECD Guidelines for the tenting of chemicals. 23-03-2006.
37
Influence of the experimental conditions on the electrodegradation of tetracyclines
A. Fernandes1, C. Oliveira1, N. Monteiro1, C. Brinzilla2, M.J. Pacheco1, L. Ciríaco1, A. Lopes1 1UMTP and Department of Chemistry, University of Beira Interior, Covilhã, Portugal
2 Faculty of Electrical Engineering, The “Gheorghe Asachi” Technical University of Iasi, Iasi, Romania
Abstract The anodic oxidation of two antibiotics of the class of tetracyclines, tetracycline and oxytetracycline, was performed in different experimental conditions, namely varying the operation mode of the electrochemical reactor, the flow rate, the type of electrolyte and the current density. For all the experimental conditions tested, the degradation of both tetracyclines was very high, showing that anodic oxidation can be an alternative or a complement to treat wastewaters containing these type of antibiotics. For the experimental conditions tested, it was also observed that an increase in the flow rate or in the current density leads to an increase in the organic load removal rate. The presence of chloride in the solution also leads to a faster chemical oxygen demand removal rate, but decreases the removal rate of the organic carbon, contributing to a poor mineralization of the organic compounds present in the solution.
Introduction In the last decades, antibiotics are being used in concentrates of animal feed, in order to prevent disease and promote growth of livestock. It is estimated that more than 70% of the antibiotics used in the United States are consumed by animals [1]. This consumption, which has the purpose of prevention or therapy, is largely determined by modern animal breeding and fattening methods and conditions, and some studies have found that the administration of antibiotics at low doses in animal feeds improve the quality of the product, with a lower percentage of fat and higher protein content in the meat [2]. In spite of the excessive use of antibiotics for some decades, only recently the existence of these substances in the environment and the consequent environmental risks they may pose have been noticed [3-5]. In fact, antibiotics and its metabolites can be found in terrestrial and aquatic environment as pseudo-persistent pollutants and have become one of the most environmental worrisome because of its potential adverse effects on humans and on the aquatic environment [6]. Among all the antibiotics, tetracyclines are a class of broad spectrum antibiotics which have been used since 1940 against a wide range of Gram-negative and Gram-positive bacteria, either as antibacterial agents in human and veterinary medicine or in sub-therapeutic levels to prevent epidemics and increasing the rate of growth and the animal weight. Their long term use results in the introduction of these compounds into the environment via
various routes including municipal and hospital wastewaters, animal manure and agricultural runoff. In Portugal, there are recent studies concerning the existence of such pollutants in the environment [7]. The persistence of activity of the tetracyclines stems from continuous release into aquatic environments via sewage, surface water, groundwater, drinking water and sludge, due to ineffective removal by conventional water treatment. Faced with this problem, there is a need to develop alternative methods for the removal and degradation of these compounds. One alternative is to develop advanced processes oxidation-reduction as photolysis, ozonation, heterogeneous photocatalysis, photo-Fenton and anodic oxidation [8-13]. However, there is still little information about the identity of the degradation products formed and the toxicity of the sample after treatment, all fundamental information to ensure the safety and effectiveness of the implementation of such procedures in the treatment of effluents containing residues of drugs. Thus, it is necessary that the treatment processes guarantee the complete degradation of the drugs or its conversion to non harmful by-products. The objective of this work was to study the influence of several experimental parameters on the electrodegradation of tetracyclines, tetracycline (TC) and oxytetracycline (OxT) (Figure 1), on the extension of their mineralization.
CH3 CH3N
NH2
O
OH
OOH
OHOH O
CH3 OH OH
CH3 CH3N
NH2
O
OH
OOH
OOH OH
CH3 OH
Figure 1. Tetracycline and oxytetracycline chemical structures.
Materials and Methods The tetracyclines used in this study were purchased from Sigma Aldrich (purity 99%) and used without further purification. Tetracycline degradation experiments were conducted in two experimental set-up, both with useful volume of 200 mL, using an initial concentration of 100 ppm of TC or OxT, with different operation mode: batch, with stirring (cell A), and batch, up-flow with recirculation (cell B). Both electrochemical reactors were composed by a BDD anode (cell A-10 cm2; cell B-20 cm2), obtained from Adamant Technologies, and a stainless steel cathode (with area identical to that of the anode. In the up-flow reactor, the recirculation of the solution was enabled by a pump,
38
Concessus, little giant, 2md, that allowed the use of different flow rates. A GW, Lab DC, model GPS-3030D (0 30V, 0 3A), was used as power supply. The assays were conducted at room temperature, adding as support electrolyte anhydrous sodium sulphate or sodium chloride (both Merck, 99.5%), with a concentration of 5 g L-1. The imposed current density varied between 2.5 and 30 mA cm-2. Degradation tests were monitored by total organic carbon (TOC), measured in a Shimadzu TOC-V CPH analyser combined with a TNM-1 unit, and chemical oxygen demand (COD), performed using closed reflux and titrimetric method [14]. UV-Visible absorbance spectra were also performed, with measurements made between 200 and 800 nm, using a Shimatzu UV-1800 spectrophotometer. High performance liquid chromatography (HPLC) was also conducted, using a Merck-Hitachi LaChrom Elite HPLC system equipped with a diode array detector L-2455, a Column Owen L-2300 and a pump L-2130. A RP-18 reversed phase Purospher® STAR (Merk) column (250 mm x 4 mm, I.D. 5 µm) was used. The selected wavelength was 360 nm. The elution was performed isocratically with an oxalic acid aqueous solution (0.01M):acetonitrile, 70:30 (v/v), mixture at a flow rate of 1 mL/min and 40 ºC. The acetonitrile and oxalic acid were HPLC grade and supplied by Sigma-Aldrich. All the solutions for HPLC were prepared with ultrapure water obtained with Milli-Q® equipment.
Results and Discussion In figure 2 it can be observed the variation in time of the several controlling parameters for the degradation of TC in cell A. There is a regular decay with time of all the parameters, showing that the degradation of TC can be performed with this experimental set-up with very good rate and without the formation of different species, at least species that absorb in the UV zone of the spectra.
Figure 2. Absorbance (a) and COD and TOC (b) decays with time for the assay performed with TC in cell A, using Na2SO4 as electrolyte. The influence of the flow rate in the assays run with cell B was tested with both tetracyclines. For TC (Figure 3a), data obtained in this work is compared with data from ref [13], obtained in the same experimental set-up. There is an increase with flow rate of the removals in COD and
TOC. Regarding absorbance, at both wavelengths considered, the influence of flow rate is not so obvious. For OxT (Figure 3b), there is again an increase with flow rate of the removals of COD, TOC and OxT concentration, determined by HPLC. This behaviour must be due to the increase in turbulence, promoted by the increase in flow rate, that improves the mass transfer. In fact, for the pollutant concentration used and the imposed current density, the assays are controlled by mass transfer, and thus, better mass transfer processes lead to the increase in the degradation rate.
Figure 3. Variation of COD, TOC, Abs and concentration in time for the assays run at different flow rates: a) TC, 30 mA cm-2; b) OxT, 20 mA cm-2. FR1 – 35 L/h; FR2 – 50 L/h; FR3 – 75 L/h. The influence of the electrolyte was also studied using as pollutant TC. The obtained results are presented in Table 1, and it can be observed that the removal in COD is not very dependent on the electrolyte. However, the presence of chloride in solution decreases the TOC removal rate. This aspect can have a dramatic effect on the mineralization rate of the pollutant, since lower TOC removal for equal COD removals means lower mineralization of the parent compound under study. Table 1. COD, TOC and concentration removals for the assays run with tetracycline using different electrolytes: cell B; flow rate of 100 L/h; current density 30 mA cm-2.
% Removal Electrolyte COD3h TOC3h [TC]HPLC-1h
Na2SO4 81 83 99
NaCl 80 20 99 Another parameter that can have an important role in the degradation is the applied current density, because its relation with the concentration determines if the electrodegradation process is controlled by kinetics of the electrodegradation reaction or by the diffusion of the pollutant molecule from the bulk of the solution to the reaction zone, near the electrode surface. The study of the influence of the current density was conducted in cell A, using OxT as the model molecule and the results are presented in Figure 4. There is an increase in COD removal rate with current density that is not so obvious
39
for the TOC removal rate. These facts have an effect on the mineralization rate, which can be observed in Figure 4, part c, where a decrease in the slope of the plots of TOC vs. COD with the increase in current density is evident.
Figure 4. Influence of the current density on the COD (a) and TOC (b) removal rates and on the mineralization index (c), i.e., variation of the TOC with COD in time: OxT; cell A; Na2SO4 as electrolyte.
Conclusions From this preliminary study the following conclusions can be drawn: The extent of the degradation of both tetracyclines was very high, showing that anodic oxidation can be an alternative or a complement to treat wastewaters containing these type of antibiotics.
For the experimental conditions tested and for both antibiotics, an increase in the flow rate leads to an increase in the organic load removal rate.
The presence of chloride in the solution leads to a faster chemical oxygen demand removal rate, but decreases the removal rate of the organic carbon, contributing to a poor mineralization of the organic compounds present in the solution.
For low applied current densities, COD and TOC removal rates increase with the current intensity. However, the increase is higher in the COD removal rate, which implies that an increase in the current density leads to lower mineralization rate.
References [1] Gaskins, H.R., Collier, C.T., Anderson, D.B.,
Antibiotics as growth promotants: mode of action. Anim. Biotechnol. 13, 29–42, 2002.
[2] Cromwell, G.L., Why and how antibiotics are used in swine production. Anim.Biotechnol. 13, 7–27, 2002.
[3] Hirsch, R., Ternes, T., Haberer, K., Kratz, K.L., Occurrence of antibiotics in the aquatic environment. Science of Total Environment, 225, 109-118, 1999.
[4] Kümmerer, K., Antibiotics in the aquatic environment – A review – Part I Chemosphere 75, 417–434, 2009.
[5] Kümmerer K., Antibiotics in the aquatic environment – A review – Part II. Chemosphere 75, 435–441, 2009.
[6] Zeh, J.A., Bonilla, M.M., Adrian, A.J. Sophia Mesfin S., Zeh, D.W., From father to son: transgenerational effect tetracycline on sperm viability. Scientific Reports 2, 375, 2012.
[7] Pena, A., Paulo, M., Silva, L. J. G., Seifrtová, M., Lino, C. M., Solich, P., Tetracycline antibiotics in hospital and municipal,wastewaters: a pilot study in Portugal. Anal Bioanal Chem 396, 2929–2936, 2010.
[8] Wang, P., Yap, P.S., Lim, T. T., C-N-S tridoped TiO2 for photocatalytic degradation of tetracycline under visible-light irradiation. Applied Catalysis A: General, 399, 252-261, 2010.
[9] Wang, P., He, Y.L., Huang, C. H., Reactions of tetracycline antibiotics with chlorine dioxide and free chlorine. Water Research, 45, 1838-1846, 2011.
[10] Jeong, J., Song, W., Cooper, W.J., Jung, J., Greaves, J., Degradation of tetracycline antibiotics: Mechanisms and kinetic studies for advanced oxidation/reduction processes. Chemosphere, 78, 533-540, 2010.
[11] Melo, S.A.S., Trovó, A.G., Bautitz, I.R., Nogueira, R.F.P., Degradação de fármacos residuais por processos oxidativos avançados. Química Nova, 32(1), 188-197, 2009.
[12] Chen, Y., Hu, C., Qu, J., Yang, M., Photodegradation of tetracycline and formation of reactive oxygen species in aqueous tetracycline solution under simulated sunlight irradiation. Journal of Photochemistry and Photobiology, A: Chemistry, 197, 81-87, 2008.
[13] Brinzila, C.I., Pacheco, M.J., Ciríaco, L., Ciobanu, R.C., Lopes A., Electrodegradation of tetracycline on BDD anode. Chemical Engineering Journal, 209, 54-61, 2012.
[14] Eaton, A., Clesceri, L., Rice, E., Greenberg, A., Franson, M.A., Standard Methods for Examination of Water and Wastewater, twenty-first ed. American Public Health Association, Washington, DC, 2005.
Acknowledgements
Fundação para a Ciência e a Tecnologia, FCT, for the project PEst-OE/CTM/UI0195/2011 and for the grant awarded to Annabel Fernandes, SFRH/BD/81368/2011.
40
A new medical textile: L-cysteine functionalized cotton, its mechanism of action and potential antimicrobial properties
M. Pedrosa1,2, E. Caldeira1, F. Silva2, A. Oliveira 2, I. Gouveia1 1R&D Unit Textile and Paper Materials, University of Beira Interior, 6201-001 Covilhã, Portugal
2CICS-UBI Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal
Abstract The innovative approach of this work concerned the development of a new medical textile functionalized with L-cysteine that act as an antimicrobial agent against Staphylococcus aureus, Klebsiella pneumoniae and Candida spp. In recent studies by Gouveia, I. et al. 2011 1, an innovative approach based on the application of L-cysteine as an antimicrobial agent for wool1. A durable antimicrobial effect over Staphylococcus aureus and Klebsiella pneumoniae was obtained without cytotoxicity 1. Therefore, it was important to assess the effect of a L-cysteine finish applied to cotton. To do so, the pre-activated cotton was functionalized using an exhaustion procedure and it was observed a bacteriostatic effect for a L-cysteine concentration of 5% over the weight of fabric, against Staphylococcus aureus and Klebsiella pneumoniae. The antifungal effect of a L-cysteine solution on Candida spp. was observed at a minimal inhibitory concentration of 3.5 mg/mL for C. albicans and 0.88 mg/mL for C. parapsilosis. However, studies on the antifungal potential of the cotton functionalized with L-cysteine are still being made. Using flow cytometry, it was possible to establish the mechanism by which L-cysteine induces growth inhibition. There were alterations in the metabolic activity of the microorganisms made by the application of L-cysteine. These studies allow the development of a new medical textile, non-toxic and environmentally friendly, unlike most commonly used processes for this purpose. Moreover, the process of functionalization can easily be transposed to large-scale implementations in the textile industry, admittedly at competitive costs.
1. Introduction The emergence of antibiotic resistant microorganisms over the last few years is a major concern. Therefore, a localized rather than systemic administration of antimicrobial agents is highly desirable. Furthermore, the use of amino acids as substitutes for antibiotic treatment is a good strategy to prevent bacterial resistance, since there is clearly a need for new types of antimicrobial agents to
upon a broad spectrum of microorganisms. Cotton is one of the most important natural fibers used in textile industry2. Cellulose fibers have a wide range of applications as medical textiles due to its unique characteristics, such as high moisture and liquids, a low content of impurities, antistatic properties and good mechanical properties. However, cotton, as well as other
natural fibers, is an excellent surface for the growth and development of microorganisms. Due to their molecular structure and a wide active surface, cellulose fibers are also a good matrix to develop bioactive and biocompatible smart materials, being an attractive material for antimicrobial functionalization. Surface modification of cellulose fibers is a good way to provide functionality on textiles for the use in medical applications3. Additionally, the textile industry constantly looks for eco-friendly processes that can substitute currently used toxic textile chemicals4. Most important classes of antimicrobial agents are used in the textile industry. Generally, these agents per se are not new and have been used in various industries. However, its adhesion to the textile surface or incorporation into the fibers reduces their activity and limits their availability. In addition, their properties may be lost gradually during the use and washing cycles. For these reasons, it is necessary to apply large quantities of those products in textiles, to control bacterial growth and maintain its durability5,6. Some of the agents commonly used in this type of textile materials are chemical compounds that present some risk to the environment and to the human body. The main compounds used as antimicrobial agent in textile materials are metals (like silver) and metallic salts, quaternary ammonium compounds, Polyhexamethylen biguanide (PHMB), triclosan, N-halamine compounds, peroxides and certain synthetic dyes 3,5,6. The use of synthetic chemicals can raise several undesirable consequences, in particular, the potential contamination of the effluents. Thus, to overcome these limitations, the development of new techniques and processes that use antimicrobial agents of natural origin has increased, not only due to its high biodegradability but also, the possible reduction in the adverse reactions caused to the users and the materials3,7,8. Some of these compounds have other beneficial properties such as, antioxidant activity, which in association with antimicrobial properties can be helpfulin the development of medical textiles (anti-inflammatory and anti-cancer) and in the controlof free radicals levels, preventing adverse reactions. The most important antimicrobial natural compounds employed are chitosan, natural dyes, aloe vera, essential oils and some plant extracts, honey, and amino acids5,6,9,10. Cysteine (Cys) is an uncharged polar amino acid with the polarity of its R groups being due to their sulfhydryl groups. The sulfhydryl groups play an essential role in the structure of several proteins by the formation of covalent bonds between parts of a polypeptide molecule or between two different polypeptide chains. This amino acid is involved in many metabolic processes either
41
directly or by its derivatives11. As Cys is a highly reactive compound, it is not surprising that it affects several enzymatic reactions in vitro and a large number of microorganisms in various metabolic functions. These effects are responsible for Cys effect against microorganisms, a phenomenon which is still unclear12. In order to develop a new textile with antimicrobial properties, this study focused on the assessment of the most effective method for L-cys biofunctionalization of cotton fibers.
2. Materials and Methods 2.1. Minimal inhibitory concentration of L-cysteine activity against Staphylococcus aureus and Klebsiella pneumoniae
The minimal inhibitory concentration of L-cys against bacteria was determined using the broth macrodilution method, as described by CLSI reference M07-A6 standard method12. According to the guidelines, the minimal inhibitory concentration was determined by serial dilution (1:2) in Mueller-Hinton Broth (MHB) (Sigma-Aldrich, St. Louis, MO) with concentrations of L-cys ranging from 50.00 mg/mL to 3.125 mg/mL. 2.2. Minimal inhibitory concentration of L-cysteine activity against Candida spp.
The minimal inhibitory concentration of L-cys against Candida spp. was determined using the broth macrodilution method, as described on CLSI reference M27-A313. L-cysteine was previously dissolved in sterile distilled water to a final concentration of 28 mg/mL. 2.3. Cotton functionalization process with L-cysteine
First of all, the fabric was washed with a standard soap to remove any surface residues that could provide a false positive in relation to antimicrobial activity. Then the surface of the fabric was oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO), which converts hydroxyl groups of Carbon-6 into carboxylate
14. A solution of TEMPO; sodium bromide (NaBr) and sodium hydrochloride (NaOCl) was prepared and its pH value was adjusted to 10.5. Then, fabric samples were submersed in the previous solution and stirred for 60 minutes. Afterwards, the pH of the solution was adjusted to 7 and the samples were washed in deionized water. After the activation process, the cotton samples were submitted to the functionalization process by exhaustion.
For the exhaustion functionalization process, a solution of 5% (w/w) over the weight of the fabric (owf) of L-cys was prepared. This concentration value was chosen after some yet unpublished studies of L-cys concentration in cotton samples. The fabric sample was immersed in bioactive solution, at a liquor ratio of 1:50, then placed in the containers of the Ahiba datacolor dying machine and submitted to 80ºC for 60 minutes, at 15 rpm. At the end of incubation, all samples were washed and dryed.
2.4. Antibacterial activity of the functionalized cotton
Control samples (without L-cys) and functionalized samples (with L-cys) were tested for its antimicrobial effect. The antibacterial effect of functionalized textile samples was tested according to the Japanese Industrial Standard, JIS L Standard 1902:200215. The evaluation of the antimicrobial effect against S. aureus and K. pneumoniae of the functionalized samples was performed by a quantitative test (suspension test), by the direct contact of the biomaterial with a suspension of bacterial cells.
2.5. Anti-Candida activity of the functionalized cotton
erformed yet. However its procedure is still described here since it has already been established. The antifungal efficiency of fabrics will be quantitatively evaluated, using Candida spp. control samples (without L-cys) and functionalized samples (with L-cys)16.
2.6. Evaluation of L-cys cytotoxicity
The release of toxic substances from a textile product with skin contact is a precondition for the formation of skin irritations. Therefore, examination on cytotoxicity permits the evaluation of the danger potential for a skin irritation. The cytotoxicity test was carried out by Gouveia I. et al. (2011)1, for 6% over weight of the fabric of L-cys. Once the antibacterial agent is the same, toxicity effects should be the same also and since L-cys cytotoxic effects, it can be considered a safe antibacterial agent. 2.7. Flow cytometry - Study of bacterial mechanism of action
The bacterial concentration for this test was 1x106 CFU/mL17. Staining protocols for the Flow Cytometry experiments were the following:
a) For membrane permeability assessment, suspensions of Gram positive and Gram negative cells were incubated
-Aldrich, St. Louis, MO) in PBS buffer (pH 7.4). Gram positive bacterial suspensions were incubated for 5 min at room temperature and Gram negative bacteria were incubated for 15 min at 37 ºC.
b) In order to assess metabolic activity, suspensions of Gram positive and Gram negative cells were incubated
trazolium chloride (CTC) (Polysciences, Inc., Warrington, PA) in Nutrient Broth and incubated for 60 min at 37 ºC and 150 rpm.
c) For the evaluation of membrane potential, suspensions
bis-(1,3-dibutyl-barbituric acid) trimethine oxonol (BOX)(Molecular Probes, Invitrogen, part of Life
42
Technologies) in PBS buffer with 4 mM EDTA (pH 7.4). Gram negative bacteria were incubated for 15min at 37 ºC.
d) For the staining of Gram positive bacteria, in order to differentiate bacterial cells from noise due to the reduced size of S. aureus cells, after labelling with PI and CTC, 10 µg/mL of fluorescein isothiocyanate (FITC) (Sigma-Aldrich, St. Louis, MO) was added to each cell suspension and incubated for 15min at room temperature. The cell suspensions were washed twice in PBS buffer (pH 7.4) and resuspended in the same buffer.
e) Exponentially-grown cells (18h at 37ºC, 150 rpm) were used as negative control for PI and BOX staining protocols and as positive control for CTC staining.
f) Prior to the flow cytometric analysis, all cell suspensions were washed once in PBS buffer (pH 7.4) and resuspended in the same buffer. Experiments were performed in duplicate.
Bacterial samples were analysed on a CyAn ADP (Beckman Coulter Inc., Brea, CA). Acquisition was performed with Summit Software (Beckman Coulter Inc., Brea, CA). The acquisition was based on light scatter and fluorescence signals resulting from 15 mW laser illumination at 488 nm. Light scatter measurements and fluorescence measurements were acquired logarithmically. Signals corresponding to forward and side scatter (FS and SS) and fluorescence were accumulated. Threshold levels were set on SS to eliminate noise or particles much smaller than intact cells with the exception of FITC-labelled S. aureus cells where the threshold level was set on FITC. Bacterial cells were gated according to FS/SS parameters. Sample acquisition was performed at low flow rate setting, a total of 10000 events were acquired for each sample. Data analysis was performed using FCS Express version 4 Plus Research Edition (De Novo Software)17.
2.8. Flow cytometry - Study of Candida spp. mechanism of action
Membrane permeability caused by L-cys on fungal cells was elucidated by flow cytometry18. In summary, after incubating 106 cells/mL for 1 hour at 37 °C with L-cysteine at half MIC, MIC and double MIC, the cells were stained with 1 µg/ml propidium iodide (Sigma-Aldrich, Portugal), protected from light, at room temperature, during 15 min. PI is a fluorescent probe that selectively stains cells with severe membrane damage. Following the cells were analyzed on a FACSCalibur cytometer (BD Biosciences, Sydney, N.S.W., Australia) at FL3 (620 nm red). Nontreated and non-PI-stained cells were used to determine autofluorescence; nontreated and stained cells were used as viability control, and yeast cells treated with 70% ethanol for 10 min were used as a death control. After treatment with L-cysteine for 60 min, cells were plated on agar medium for evaluation of the number of
colony-forming units (CFU). For kinetic studies, yeast cells were incubated during 5, 10, 15 and 30 min with L-cysteine at MIC and stained with PI using the protocol described above. Other probes were used like FUN-1, Rhodamine 123; Dibac to acess the mechanis of action of L-cysteine against Candida albicans and Candida parapsilosis.
Results and Discussion
3.1. Minimal inhibitory concentration of L-cysteine activity against Staphylococcus aureus and Klebsiella pneumoniae
The minimal inhibitory concentration (MIC) value for Klebsiella pneumoniae was 50 mg/mL and for Staphylococcus aureus was 25 mg/ml. The different values for the two strains can be explained by the structure of Gram-positive and Gram-negative bacteria, since Gram-negative microorganisms have an outer membrane that further protects bacteria, unlike Gram-positive. 3.2. Minimal inhibitory concentration of L-cysteine activity against Candida spp. The results of MIC values for Candida albicans ATCC 10231 and Candida parapsilosis MP35 were respectively 3.50 and 0.88 mg/mL. 3.3. Antibacterial activity of the functionalized cotton Antimicrobial tests showed a decrease in bacterial growth for the two strains at different concentrations. For S. aureus, it was observed a growth reduction of 85.33 % for L-cys functionalized samples. For the K. pneumoniae strain, a growth reduction of 83.33 % was visible for L-cys functionalized samples. These growth reduction values demonstrated that L-cys has the ability to cause a marked decrease in bacterial growth (85.33 % for S. aureus and 83.33 % K. pneumoniae) with L-cys concentrations in cotton samples of approximately (1 mg/mL) which is a much lower value than the MIC obtained for each strain (K. pneumoniae 50 mg/mL and S. aureus 25 mg/mL), which shows the effective binding of this compound to the cotton fibres, promoting an antibacterial effect. These results demonstrate that activation of cotton samples with TEMPO is critical in order to fixate L-cys; via a depletion process it is possible to obtain cellulosic materials with antibacterial properties. L-cys concentrations required to promote bacterial inhibition are relatively low, this can be explained by the amino acid bounding to the fabric fibres which leaves more free thiol groups, promoting a higher antibacterial effect. On the other hand, when in solution the amino acid can aggregate by forming disulfide bonds between molecules of L-cys, decreasing the availability of these groups to interact with bacteria, such as demonstrated previously by Gouveia I. et al. (2011)1.
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3.4 Evaluation of L-cys cytotoxicity
This study showed that 6% over weight of the fabric of L-cys cytotoxicity, since the cellular viability reduction was less than 30%. Therefore it can be considered a safe antibacterial agent without any danger of skin irritation1.
3.5. Flow cytometry - Study of bacterial mechanism of action Flow cytometry tests for bacteria in suspension were conducted using the MIC value obtained for each bacterium and the results are displayed in Table 1.
The results obtained for K. pneumoniae showed that there is a small membrane depolarization (BOX positive cells) in cells incubated with L-cys. However, the primary mechanism of action of L-cys on Gram-negative bacteria seems to be the alteration of metabolic activity, since there is a decrease in the number of metabolic active cells (CTC positive cells) after incubation with L-cys with a reduction of about 94.26 % to 2.62 % CTC positive cells. The changes on PI labelling showed no significant alterations, so there was no effect on bacterial membrane permeabilization (PI positive cells), which could have resulted in bacterial cell death.
Table 1- Percentage of fluorochrome stained cells evaluated by flow cytometry and viability reduction evaluated by the drop-plating method of bacteria treated with L-Cys
Regarding the results obtained for FITC-labelled S. aureus (table 3), similarly to K. pneumoniae, there is a marked reduction in metabolic activity from approximately 91.08 % metabolic active cells to about 1.46 %, which is lower than the reduction observed for K. pneumoniae. Also, for S. aureus, the percentage of PI positive cells is low, so no cell death effect can be considered. Considering this results, it can be stated that the main mechanism of action of L-cys on both K. pneumoniae and S. aureus, is the reduction in metabolic activity. This is consistent with the bacteriostatic effect of L-cys on both of these bacteria, seen by the death curves (made in a previous study). In fact, changes in metabolic activity can cause permanent damages and prevent bacterial growth. 3.6. Flow cytometry - Study of Candida spp. mechanism of action Regarding Candida spp. cytometric assays there was an alteration in metabolic activity after incubation with L-cys (Figure 1 and 2).
Figure 1 - C. parapsilosis MP35 stained with Rhodamine 123
Figure 2 - C. albicans ATCC 10231 stained with Rhodamine 123
Sample viability reduction
(%)
PI positive cells
(%)
CTC positive cells
(%)
BOX positive
cells (%)
K. pneumoniae
Positive Control 0.38 97.39 13,74
Negative Control 100 65.56 11.54 75,75
control 0.65 ± 0.19 94.26 ± 1.77 4,20 ± 0,12
MIC 79.88 ± 1,94 0.90 ± 0.55 2.62 ± 0.37 8,05 ± 0,60
S. aureus
Positive Control 1.89 67.13
Negative Control 100 67.28 18.75
control 2.73 ± 1.15 91.08 ± 6.84
MIC 98.9 ± 1.13 1.88 ± 0.09 1.46 ± 0.53
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Conclusions With this work it was found that the L-Cys finish applied to the cotton has a bacteriostatic effect against the two bacterial strains under investigation, L-Cys is closely linked to fibers, and it is obtained by an exshaustion process carried out under conditions similar to other textile finishings. In this study was also possible to establish, by flow cytometry, the mechanism by which the thiol groups induce growth inhibition. The main mechanism of action of L-Cys against K. pneumoniae, S. aureus, Candida albicans ATCC 10231 and C. parapsilosis MP35 is the occurrence of changes in metabolic activity of these microorganisms. With this study it was possible to develop a new antimicrobial finish for cotton and cellulosic fibers, non- toxic and environmentally friendly, unlike most commonly used processes for this purpose; similar to other textile finishing, allowing its implementation in equipment normally used in textile industry, making it a new method with a high probability of industrial application. This research allowed, for the first time, to elucidate the mechanism of action of L-Cys against S. aureus, K. pneumoniae, Candida albicans ATCC 10231 and C. parapsilosis MP35, which is of great scientific importance because it contributes to the innovative and clear knowledge about the L-action against these microorganisms. A new antimicrobial finish for cotton similar to other textile finishes and eco-friendly was obtained. Still this procedure is easy to perform and uses the same equipment as other textile treatments, which increases its industrial application. References 1 Gouveia I., Sá D. and Henriques M. 2011.
Functionalization of Wool with L-Cysteine: Process Characterization and Assessment of Antimicrobial Activity and Cytotoxicity. Journal of Applied Polymer Science, 124: 1352 1358.
2 Son, Y.-a, Kim, B.-soon, Ravikumar, K., & Lee, S.-goo. (2006). POLYMER Imparting durable antimicrobial properties to cotton fabrics using quaternary ammonium salts through 4-aminobenzenesulfonic acid chloro triazine adduct. European Polymer Journal, 42, 3059-3067.
3 Sonjak S., Cimerman G., et al (2011). Antimicrobial efficiency of functionalized cellulose fibers as potential medical textiles. Health Care, 36-51
4 Lim, S.-H., & Hudson, S. M. (2003). Review of chitosan and its derivatives as antimicrobial agents and their uses as textile chemicals. Journal of Macromolecular Science-Polymer Reviews, C43(2), 223 269
5 Gao Y., Cranston, R. (2008). Recent Advances in Antimicrobial Treatments of Textiles, Textile Research Journal 78, 60-72
6 Gouveia I.C. (2010). Nanobiotechnology: A new strategy to develop non-toxic antimicrobial textiles. Applied Microbiology, 407-414
7 Borkow G., Gabbay J. (2008). Biocidal textiles can help fight nasocomial infections. Medical Hypotheses 70, 990-994
8 Schindler W. D., Hauser P. J. (2005). Chemical Finishing of Textiles, The Textile Institute, Woodhead Publishing Ltd, CRC, cap 15, p165-174
9 Ramachandran T., Rajendrakumar K., Rajendran R. (2004). Antimicrobial Textiles - an Overview. IE (I) Journal-TX 84, 42-47
10 Joshi M., Ali S. W., Purwar R. (2009). Ecofriendly antimicrobial finishing of textiles using bioactive agents based on natural products. Indian Journal of Fiber Textile Research 34, 295-304
11 Kari C., Nagy Z., Kovács P., Hernádi F. (1971). Mechanism of the Growth Inhibitory Effect of Cysteine on Escherichia coli. Journal of General Microbiology 68, 349-356
12 National Committee for Clinical Laboratory Standards. 2003. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard M7-A6. National Committee for Clinical Laboratory Standards, Wayne, Pa.
13 National Committee for Clinical Laboratory Standards. 2008. Reference method for broth dilution antifungal susceptibility testing of yeasts; approved standard M27-A3, National Committee for Clinical Laboratory Standards, Wayne, Pa.
14 Gomes A.P., Mano J.F., Queiroz J.A., Gouveia I.C. (2010). Assessment of bacteria-textile interactions using Scanning Electron Microscopy: A study on LbL chitosan/alginate coated cotton. Microscopy: Science, Technology, Applications and Education (1), 286-292.
15 JIS L 1902:2002 (Japonese Industrial Standard). Testing for antibacterial activity and efficacy on textile products.
16 , J.,
pretreated polyester and polyamide fabrics loaded with Ag nanoparticles. Journal of Materials Science, 44: 3983 3990.
17 Silva F., Ferreira S., Queiroz J.A., Domingues F.C. (2011). Coriander (Coriandrum sativum L.) essential oil: its antibacterial activity and mode of action evaluated by flow cytometry. Journal of Medical Microbiology, 1479-1486
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18 Pina Vaz, C., et al., Cytometric approach for a rapid evaluation of susceptibility of Candida strains to antifungals. Clinical microbiology and infection, 2001. 7(11): 609-618.
Acknowledgements
The authors would like to thank Fundação para a Ciência e Tecnologia (FCT) for the funding granted nconcerning the project - PTDC/EBB-BIO/113671/2009 Skin2Tex. Also we would like to thank Fundo Europeu de Desenvolvimento Regional (FEDER) through COMPETE
Programa Operacional Factores de Competitividade (POFC) for the co-funding.
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Treatment of cork processing industrial effluent with an innovative system of Constructed Wetland and Ozonation
Diana Santos(1), Williams Silva(1), Arlindo Gomes(1), Rogério Simões(1), Roberto Pascoa(1), António Albuquerque(2) and Alexandros Stefanakis(3)
(1)Unity of Textile & Paper Materials and Department of Chemistry, University of Beira Interior, Covilhã - Portugal; (2)Department of Civil Engineering and Architecture, University of Beira Interior, Covilhã – Portugal;
(3)Department of Environmental Engineering, Democritus University of Thrace, Thrace – Greece;
Abstract
The performance of two constructed wetlands (CWs) with horizontal subsurface flow (HSSF) configuration was investigated during a three phases treatment of cork boiling wastewater (CBW). The two CWs were filled with LECA. One was planted (CWP) with common reeds (Phragmites australis) and the other was kept unplanted as a control unit (CWC). The feeding CBW was sequentially diluted to 500, 600 and 750 mg/L COD and pH was set to 6.5-7.5. Other features of the feed solution were the intense dark colour, total phenols (TPh) concentration ranging from 36 to 62 mg/L and low biodegradability. Both CW units showed similar COD (44.7 and 56.6%, respectively) and TPh (40 and 65%, respectively) removal rates for a working period of 4 months. First results indicate that the presence of plants improved the system performance only in terms of total phosphorus (TP) removal (33% and 9% in the CWL and CWC unit, respectively). After phase 1 (500 mg/L influent COD) the major drawback was the absence of decolourization which was close to null or negative. To increase decolourization, ozonation was implemented as a post-treatment stage. However, the amount of ozone used was limited to 18.9±2.3 mg to keep the cost low. Despite the limited mean yield of 27%, it was possible to achieve colour removal above 85% and increase the bio-degradability from 390 to 955%. These are important facts towards the pollution elimination and may consequently contribute to sustainable use of industrial water.
Introduction
The Water Framework Directive issued by the EU compels industries to the sustainable use of water. This objective requires the reduction of water consumption and of the polluted water to ensure that future generations will have equal opportunities for economic and social development.
The production of cork stoppers is the most valuable outcome of the cork industry. Therefore, the economic sustainability of the cork production is closely dependent on public preference for cork stoppers in detriment of synthetic materials. The first stage of the cork industrial process is focused on the cleaning, disinfection and
moistening of the raw material. For this purpose, the corkwood is immersed in boiling water up to one hour after dried in open air [1,2]. The amount of water used varies between 0.35 to 0.70 m³/tn, and depends on the water reuse percentage, which is limited from 3 to 6 times in the case of cork used for stoppers production. It is necessary to ensure the absence of organic contaminants, namely the 2,4,6-trichloroanisole (TCA), which may cause the spoilage of more than 80% of wine bottles during the storage. Therefore, the presence of TCA in stoppers is exhaustibly controlled by methods with detection limits between 1 and 2 ng/g and determines the possibility of its usage to seal wine bottles [3].
Cork boiling wastewater (CBW) has a dark colour and contains some corkwood extracts such as phenolic acids and tannic compounds [2]. Biological treatment is difficult to be implemented due to the high concentration of bio-recalcitrant compounds, some of them also contribute to the high effluent acute toxicity (4.1 to 12.3 toxic units, TU) [4]. The Total Phenols (TPh) content is reported to be between 1.0 and 3.5 g of gallic acid/L. The effluent COD (Chemical Oxygen Demand) varies from 1300 to 4400 mg/L and the BOD5 (Biological Oxygen Demand) is between 875 and 1800 mg/L, which corresponds to a biodegradability index (BI) (BOD5/COD ratio) below the recommended limit of 0.40 for the adoption of conventional biological treatment processes [1,2,4,5].
Adaptation of the Constructed Wetland (CW) technology meets increasing worldwide interest compared to conventional systems, namely for domestic and municipal wastewater treatment, as also for industrial wastewater such as textiles, food processing and winery industries. It appears as a sustainable alternative to fulfill the requirements of a respective biological treatment [6]. CWs offer a series of ecological, economical and engineering benefits, including high nutrient absorption capacity, simplicity, process stability, no sludge production, reduced construction, operation and maintenance costs and creation of a wildlife habitat, which allow for resource conservation and environmental protection [6]. In addition, CWs show good effectiveness in the removal of organic matter (up to 80% for COD), total phosphorus (TP), total nitrogen, etc. [6,7]. Among the several possible configurations for the CW systems the most common in Portugal and in most European and
47
Mediterranean countries are the horizontal subsurface flow (HSSF) systems used for BOD5 and suspended solids removal from wastewater [6].
Systems with subsurface flow promote the passage of the wastewater through a porous media in which aquatic plants are growing. They have a high tolerance even in cold climates, and practically no odour and mosquito appearance. The transformations and removal of influent pollutants occur through a series of chemical (redox, precipitation), physical (filtration, sedimentation, adsorption) and biological (biodegradation, nitrification) processes [6-8].
The substrate media promotes plant fixation and the development of the biofilm. Clogging problems used to be a problem but today are not very extended. Although clogging mechanisms are not yet very well understood, it is known that suspended solids accumulation, biomass growth, chemical precipitation and rhizomes and roots development are the main mechanisms [7,9]. Light-expanded clay aggregate (LECA) has been used as an alternative substrate media to prevent clogging and increase the treatment capacity. It possesses high porosity and specific surface area, which allows for a good biofilm adhesion and a high hydraulic conductivity [9].
Phragmites australis is a perennial plant species most commonly used in CWs, with an extensive system of rhizomes [6,9]. This species presents a vegetative cycle that begins in the first spring months, when the shoots development shows a high growth rate. In summer the plants reach the peak of their growth (height over 2 m). The first signs of aging usually appear in autumn, and the progressive drying of the leaves and shoots can be observed during the following months, until the beginning of the next growing season [9].
Due to strict environmental regulations it is difficult to achieve the quality requirements either for effluent discharge or water reuse in the case of industrial wastewater using only CWs [6,9]. Thus, when effluents have toxic non-biodegradable pollutants the operation with partial effluent recirculation or a post-treatment stage may be necessary to comply with legislation requirements [10].
Two HSSF CW systems filled with LECA, one planted and one unplanted, were fed with diluted CBW (COD concentration of 500, 600 and 750 mg/L). System monitoring showed that colour removal in both units was only 4.5 and 23.9%, while in some cases the effluent colour increased. Thus, ozonation was tested as a post-treatment phase.
Chemical oxidation techniques are increasingly used as pre- or post-treatment of industrial effluents. In the first case, they can be applied to raw wastewater or membrane concentrates to reduce macromolecule molecular weight, increase biodegradability and reduce the toxicity, allowing for the viability of subsequent biological treatment. In the other case, they are used to deliver high
quality water appropriate for reuse or discharge [11]. One widely used procedure is ozonation, especially when hazardous and bio-recalcitrant organic and inorganic compounds are present. The powerful oxidizing capabilities of ozone and the absence of hazardous decomposition products make this a potentially useful post-treatment agent, especially when decolourization is required, like in the case of textile effluents [11].
The aim of this work is to conduct a preliminary investigation of the potential for cork processing industry effluent quality improvement with the use of an innovative combined treatment system of CWs and ozonation.
Materials and Methods
Constructed wetland systems Two HSSF CW laboratory-scale units were used: one planted with Phragmites australis (CWP) and one unplanted as a control unit (CWC). CWP dimensions are 34.8 cm x 15.0 cm (length x width), with a total surface area of 522 cm² (Fig. 1a). Respective values for CWC were 29.7 cm x 10.0 cm and 297 cm² (Fig. 1b) . Both units contained LECA as substrate media (porosity 38.33%). LECA depth in CWP and CWC units was 14.3 and 13 cm, respectively. Water depth was 9.8 cm in both units. The influent flow rate was adjusted to 9 and 16 ml/h for the CWC and CWP, respectively. The hydraulic retention time (HRT) applied in both units was 5 days.
Figure 1. Schematic representation of (a) planted CWP unit and (b) unplanted CWC unit.
Biomass The biomass used as inoculum in these experiments was collected from the aeration tank of a Wastewater Treatment Plant based on activated sludge process for domestic wastewater treatment. After the collection, the biomass was kept under vigorous aeration and fed with a solution containing glucose and acetate with balanced composition of the C:N:P ratio (100:5:1).
(a)
(b)
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Plants and start-up period Common reeds (Phragmites australis) were established in May 2012 and the unit operation started. During the first 4 weeks both units were fed with synthetic wastewater with an organic load of 300 mg/L COD (acetate) before the application of CBW. Wastewater The full operating period started with the feeding of CBW solutions of 500 mg/L COD (Phase 1). Then the organic load increased to 600 mg/L COD (Phase 2) and finally it reached 750 mg/L COD (Phase 3). Each phase lasted for 20, 18 and 33 days, respectively. Operating conditions did not change until the achievement of steady COD and TPh removal rates. Both CWs were placed indoors. Room temperature showed significant variation between May and November (35 and 14°C, respectively). Feed solutions were kept at 4°C to avoid biological degradation and pH was adjusted to 6.5 – 7.5. Post treatment Ozonation was applied as a final effluent polishing stage of both CW systems. A Fischer Model 502 ozone generator (Germany) was used to produce ozone gas from dry pure oxygen. The oxidation of CW effluents was conducted in a closed vessel of 500 mL with mechanical stirrer to promote the ozone gas transfer to the solution. The ozonation lasted 10 min and corresponded to the application of 18.9 ± 2.3 mg of ozone. The yield calculation for the oxidation was based on the difference between the initial ozone production rate (mg/min) and the amount of ozone exiting the unit and fixed in KI. All determinations were performed by the iodometric method. Ozonation was applied during phases 2 and 3. Experimental procedure Weekly samples were taken from the CWP and CWC beds at three points: influent, ½ of unit length and effluent to determine pH, COD, BOD5, TP, TPh, colour (absorbance at 580 nm – A580nm) and aromatic compounds (absorbance at 254 nm – A254 nm). CWP and CWC effluent samples were kept at 4°C. Analytical determinations were performed in triplicates. The HRT of CWs was fortnightly monitored. Analytical methods COD, BOD5 and TOC were determined according to Standard Methods [12]. TPh was determined with the Folin-Ciocalteu reagent according to the method of Ainsworth and Gilliespie and expressed in terms of tannic acid mg/L [13]. TP concentration was measured using the cuvette tests LCK 350, following the DIN 38405 D11-4 procedure, and a Hach-Lange CADAS 50 spectrometer (Germany). The sample absorbance was determined at 254 and 580 nm, which represent the aromatic-compound content and the colour of the solution, respectively. Before absorbance measurements, samples were diluted at the rates of 1:50 and 1:10 for aromatics and colour
determinations, respectively. Measurements of pH and temperature were carried out with a pH meter (713 pH meter, Metrohm) and a temperature sensor (VWR).
Results and Discussion
The characteristics of feed solutions and the performance of both CWs are presented in Table 1.
COD TOC BOD BI TPh A254 nm
Influent 550.9 219.5 148.9 0.29 36 0.125
CWP Effluent 56.6±5.2 63.3 61.1 0.21 65±1.7 20±28
CWC Effluent 55.7±8.6 60.7 35.7 0.29 64.6±3.3 25.6±18.4
Influent 628.7 352.9 74.7 0.12 47.8 0.238
CWP Effluent 52.1±8 68.2±6.3 71.7±17.8 0.04 56.5±13.6 42.02±19.75
CWC Effluent 55.8±8.9 74.9±5.7 77.7±13.3 0.03 57.5±12.4 50.84±20.17
Influent 750 330 168.3 0.13 61.9 0.252
CWP Effluent 44.7±14.7 37.0±2.6 77.8±17.1 0.06±0.02 40.2±8.3 37.3±15.5
CWC Effluent 53.6±10.8 48.8±8.0 84.1±18.1 0.06±0.02 47.0±8.0 41.1±13.6
Phas
e 1
Phas
e 2
Phas
e 3
Table 1. Characteristics of the CBW solutions used during the three operational phases and respective percentage removal rates for CWP and CWC units. (Influent; mg/L and effluent; percentage, mean value ± standard deviation).
Despite the dilutions of CBW (from 1:4 to 1:2) in order to modify the COD concentration for each treatment phase, the BI values ranged only from 0.12 to 0.27, which implies the presence of bio-recalcitrant organics. It is also interesting that both CWs presented similar removal rates for organic matter, TPh and aromatics, which varied for COD from 44.7 to 56.6% for an extended operational period (from 19 July to 5 November). During this period, mean temperature values were 34.5°C in August and 14°C in November. As temperature decreased, reed leaves started to dry in October. This was accompanied by a decrease in TP uptake by plants, since TP removal in the CWP unit decreased from 32.6 % in phase 2 to 22.1 % in phase 3, higher enough, however, compared to the unplanted CWC unit (maximum 8.6%). Moreover, results obtained during phase 1 implied that decolourization is the major issue for the system performance. Therefore, in phases 2 and 3 ozonation was tested as post-treatment.
The results achieved by ozonation of the CW effluents are presented in Table 2. Despite the small amount of ozone applied (18.9±2.3 mg), chemical oxidation allowed for a decolourization ranging from 80 to 94%, which is not dependent on the CW effluent COD. The concentration of the major class of organic pollutants, the phenolic compounds, was also reduced up to 73%, which may also contribute to the detoxification (data not yet available) and to the increase of the BI. The results show a BOD5 enhancement of 526 and 720% for CWC and CWP, respectively, in phase 2 and 307 and 206% in phase 3, probably due to the increase of the available organic matter for bio-degradation as the COD removals were decreased in phases 2 and 3.
49
COD BOD BI TPh A580nmBefore 335 12 0.03 31.2 0.065After 271 62 0.23 8.3 0.004
Variation (%)1 (-) 24 (+) 526 (+) 689 (-) 7.3 (-) 94
Before 372 9 0.02 31.2 0.065After 280 62 0.22 11.4 0.008
Variation (%)1 (-) 25 (+) 720 (+) 955 (-) 6.3 (-) 88
Before 492.2±98.5 22.3±2.7 0.06±0.02 37.1±3.6 0.060±0.006After 272.3±44.7 67.6±7.9 0.20±0.04 11.2±4.0 0.009±0.003
Variation (%)1 (-) 44.3±6.3 (+) 307±53 (+) 437±32 (-) 69.6±4.0 (-) 85.3±3.7
Before 535.0±71.4 33.0±6.0 0.06±0.01 41.2±3.7 0.072±0.003After 332.1±28.3 68.3±18.1 0.25±0.02 13.0±0.6 0.015±0.003
Variation (%)1 (-) 37.6±3.7 (+) 206±27 (+) 390±182 (-) 68.2±1.9 (-) 79.6±4.7
Phas
e 3 CW
C 2
CWP
2CW
C
Phas
e 2
CWP
Table 2. Results achieved by ozonation of the CW effluents. Units expressed as mg/L except for BI (dimensionless) and colour (A580nm); (1)(+) indicate increase and (-) indicate removal; (2)mean±standard deviation of three samples.
Due to the small ozone yield (27%) applied, the CW effluent quality of both CWs is not within the limits for discharge or reuse, since COD concentration remains above 150 mg/L.
Conclusions
Despite the small amount of ozone applied as post-treatment and the low reaction yield, the viability of this option to achieve significant removal of colour (79.6 to 94.0%) and TPh (63 to 73%) was demonstrated. The increase of BOD5 and consequently of the BI should be noticed and could also contribute to the reduction of effluent toxicity and, thus, of the environmental impact of the cork industry effluent. However, the total performance of the integrated system is not yet appropriate for effluent discharge to natural watercourses or reuse, as COD remains above the limit of 150 mg/L. Therefore, CW performance needs further improvement, which could be achieved as the maturity of the system proceeds with time and through further modification of the system setup.
Future work includes the performance evaluation of the integrated system for wastewater detoxification and comparison of the ozonation results as post-treatment and as pre-treatment for the same limited amount of oxidant and organic load.
References [1] Greeves, A.J., Churchey, J.H., Hutching, M.G., Philips, D.A.S., and Taylor, J.A., “Ozonation kinetics of cork-processing water in a bubble column reactor”, Water Res., 42, 2473, 2008. [2] Benitez, F.J., Acero, J.L., and Leal, A.I., “Application of MF and UF processes to cork processing wastewaters and assessment of membrane fouling”, Sep. And Purif. Technol., 50, 354, 206.
[3] Insa, S., Salvadó, V., and Anticó, E., “Assays on the simultaneous determination and elimination of chloroanisoles and chlorophenols from contaminated cork samples”, J. of Chromatography A, 1122, 215, 2006. [4] Mendonça, E., Pereira, P., Martins, and Anselmo, A.M., “Fungal Biodegradation and Detoxification of Cork Boiling wastewaters” Eng. Life Sci, 4, 144, 2004. [5] Bernardo, M., Santos, A., Cantinho, P., and Minhalma, M., “Cork industry wastewater partition by UF/NF: A biodegradation and valorisation study”, Water Res., 45, 904, 2011. [6] Davis, L., “A handbook of constructed wetlands”, volume 1, General Considerations, USEPA Region III with USDA, NRCS, 1995. [7] Soon-An Ong, Uchiyama, K., Inadama, D., and Yamagiwa, K., “Simultaneous removal of color, organic compounds and nutrients in azo dye-containing wastewater using up-flow constructed wetland”, J. of Hazard. Materials, 165, 696, 2009. [8] Vymazal, J. (2007). Removal of nutrients in various types of constructed wetlands, Sci. Total Environ. 380, 48–65 [9] Albuquerque, A., Oliveira, J., Semitela, S., and Amaral, L., “Evaluation of the effectiveness of horizontal subsurface flow constructed wetlands for different media” J. of Envir. Sciences, 22, 820, 2010. [10] Alexandros I. Stefanakis and Vassilios A. Tsihrintzis. Effect of Outlet Water Level Raising and Effluent Recirculation on Removal Efficiency of Pilot-scale, Horizontal Subsurface Flow Constructed Wetlands. Desalination 248 (1-3), 961 – 976, 2009. [11] Woodard, F., “Industrial Wastewater Treatment Handbook”, Butterwort Heinemann Ed., USA, 2nd Ed., 2001. [12] APHA, AWWA and FEW, “Standard Methods for the Examination of Water and Wastewater”, 20th Ed., Washington, DC, USA, 1998. [13] Ainsworth E.A. and Gillespie K.M., “Estimation of total phenolic content and other oxidation substrates in plant tissues using Folin-Ciocalteu reagent”, Nat. Protoc, 2, 857, 2007. Acknowledgements
Thanks are due to FCT and FEDER for funding the Project (PTDC/AGR-AAM/102042/2008) and Diana Santos also thanks FCT and FEDER for their Masters grants.
50
Fig. 1: Molecular structure of conducting polymers, a) polyacetylene, b) polypyrrol, c) PEDOT.
Conductive Textiles Functionalized with a Vapor Phase Polimerization Reactor
João Matos1, Isabel G. Trindade1, José Lucas1,2, Rui Miguel1,2, Amélia Rute1,3, Manuel Magrinho1,3, Madalena Pereira1,2, Manuel J. Santos Silva1,2
1Unidade de Materiais Têxteis e Papeleiros, Rua Marquês D´Ávila e Bolama, 6200-001, Covilhã 2Departamento de Ciência e Tecnologia Têxteis, Universidade da Beira Interior, Covilhã
3Departamento de Química, Universidade da Beira Interior, Covilhã
Abstract In this work, a new reactor was in-house built, to use the vapor phase polymerization (VPP) method for the coating of textile fibers with electrically conductive Poly(3,4-ethylenedioxythiophene) (PEDOT) polymer. In the applied method, liquid phase EDOT (3,4-ethylenedioxythiophene) is sublimated into vapor phase which reacts with textile fabrics previously functionalized with FeCl3 oxidant agent, coating the fabric´s textile fibers with submicron thick PEDOT polymer. The PEDOT coated textile fabric samples exhibit uniform grey color and electrical conductance. The VPP method parameters, reaction temperature and time, sample soaking and drying time, sample distance to monomer source of vapor and reactor base vacuum pressure were investigated to yield textile samples with optimum electrical conductivity, good sample homogeneity, and sample characteristics such as color and electrical conductivity repeatability. The textile samples coated with PEDOT were characterized by electrical measurements, scanning electron microscopy (SEM) and Fourier-Transform Infrared Spectroscopy on the Attenuated Total Reflectance mode (FTIR-ATR). The experimental results indicate that good electrical conductance, characterized by an electrical resistance of 30 Ω/ sq was attained with PEDOT coated polyester fabric samples. The new set up opens great possibilities to perform research and development in the field of conducting polymer coatings.
Introduction Since the pioneer works on the synthesis of polyacetylene with an electrical conductance of 1000 S/cm when exposed to iodine vapors, by Shirakawa in the early 1970s, and posterior collaboration with Heeger and MacDiamid, [1], leading to the award of the Nobel prize in 2000, new families of conducting polymers (CPs) emerged. In figure 1 are shown the molecular structures of polyacetylene, polypyrroll (PPy) and PEDOT. The molecular structure of those CPs is characterized by a backbone structure with conjugated bonds, that are alternating single and double bonds. The electrical conductance of CPs is explained by the band theory, and generally results from the hybridization of sp2 and pz electronic orbitals in the repeat unit. The sp2 orbitals contribute to the localized σ-bonds, that hold the polymer structure together, and π-bonds, resulting from the
delocalized orthogonal pz orbitals that yield the electrical conductance [1], [2]. This electrical conductivity can be enhanced by the introduction of electrical charges in the backbone of the polymeric chain, via a doping process. As it was described by other authors ([3], [4]), the doping of PEDOT can be achieved by the introduction of chloride or tosilate ions in the backbone, enhancing the electrons flow due to the formation of polarons and bipolarons, as seen in fig 2.
Fig. 2: Molecular structure of PEDOT doped with chloride ions.
51
There are several methods for the polymerization of EDOT to PEDOT, and the VPP method is proving to be the one with the best results so far, yielding conductivities up to 103 S/cm in thin films [5]. Some works combining PEDOT in textile substrates are being published [3,4,6,7], and are revealing a very promising future in the area of heart-beat sensor, other biosensors or even a wider range of uses, such as EM shielding [6] or electrical current transport [7]. In this work, EDOT was polymerized in polyester (Pes) samples via the VPP method, with a reactor configuration still not described in the present literature, in order to obtain electrically conductive PEDOT/Pes samples.
Materials and Methods A reactor for the VPP method was built, from laboratorial glassware, and it consisted in a 250 mL double wall jacketed reactor, with a flanged opening and a lid. A circulating water bath connected to the outside wall of the reactor was set to a working temperature between 50 °C and 70 °C. The lid sealed the reactor via an O-ring of rubber and integrated a glass valve connected to a vacuum pump and a vessel with a vacuum gauge. A photo of the experimental setup is shown in Fig. 3. The reactor had a diameter of 65 mm. In this VPP polymerization method, two polyester samples were soaked in the oxidant solution for a period of time between 5 minutes to 30 minutes, and then dried in air, for a period of time between 5 minutes and 30 minutes. Next, the samples were placed, side by side in a sample holder made of a plastic net, inside the reactor, where a 15 microliter drop of EDOT monomer was previously deposited in the center of the bottom of the reactor.
After sealing the reactor, the vacuum pump and water bath were connected and the reaction would begin for a period of time between 30 minutes and 120 minutes. When the reaction ended, the samples were immediately washed for five minutes in methanol once and twice in distilled water, in order to remove traces of unreacted
oxidant solution and monomer from the textile fibers. After the washing procedure, the samples were dried during 24 hours in a controlled environment (23ºC, 50% relative humidity). A schematic of the VPP polymerization method is presented in Fig. 4.
Several essays were made, to optimize sample homogeneity, sample characteristics and repeatability. The optimum VPP parameters obtained were 15 minutes of soaking time in oxidant solution, 15 minutes of drying time, and reactor temperature and polymerization time of 60ºC and 30 minutes, respectively. The base pressure in the reactor before each polymerization was -600 hPa.
The textile samples consisted of plain weave fabrics of polyester, with a density of 12.8 mg/cm2. The samples were initially washed at 90ºC with a mild detergent. After that, were dried 24 hours in a controlled environment and cut into small rectangular samples, with a rectangular geometry of 70 mm long by 5 mm wide, accurately obtained at more or less one thread. The samples were then washed in methanol for 20 min, then rinsed five times in deionized water, and left to dry in a controlled environment for at least 24h.
For the polymerization of the fabrics, iron (III) chloride (FeCl3), EDOT (97%), methanol (99,5%) were purchased from Sigma-Aldrich and Ethanol (99%) locally obtained from Fábrica de álcool - Manuel Vieira & Cª. All chemicals were used as received. The electrical characterization of the samples was performed with the two probe method, using alligator clips connecting both ends of the samples to a power supply (Hameg 8040-3) and a programmable ampermeter (Hameg 8012). The data acquisition was semi-automated via a RS232 interface and a Labview program to display in real time I-V curves and to record the mean values (over six to ten measurements) of the electrical current, I, and respective standard deviation, for each applied voltage, V. The geometric factor of the samples, given by the ratio of the distance between the probes and the width of the samples, l/W, were input to the data acquisition program, to record the value of current I* described in Eq. 1 and Eq. 1b, so that comparison among samples prepared in variable polymerization conditions could be made.
Figure 3: VPP experimental setup
Figure 4: Schematic of VPP experimental method.
52
The geometrical factors, given by the ratio l/w had typical values around 13, corresponding to mm and
mm. For each VPP condition, typically 6 samples had their V-I* curves measured. The R/sq values corresponding to each polymerization condition were measured at 5 Volt and each sample was measured at least six times. The mean and standard deviation values were calculated and used in the plots. Scanning electron microscopy (SEM) of the polymerized samples was made in a Hitachi S2700. FTIR-ATR spectroscopy was made with a Thermo Scientific NICOLET iS10 Smart iTR.
Results and Discussion V-I* curves of PEDOT/PES samples for variable oxidant concentrations between 5 wt% and 30 wt% are shown in Fig. 5. All curves exhibit high linearity with R/sq values, obtained from the slope of the curves, decreasing with oxidant concentration increase, from approximately 400 Ω/sq to 30 Ω/sq. The most accentuated electrical resistance per square decrease occurred for oxidant concentrations in the range of 5 wt% to 15 wt% as shown in Fig. 6.
The linear behavior of the V-I* curves and the R/sq decrease with oxidant concentration increase are consistent with results obtained by other researchers, regardless of the method used [3,8,9]. The trend observed in figure 6 can be explained by the increase of the available oxidant for initiating the reaction. With higher concentrations, more amount of the oxidant is available and more monomer polymerizes on the substrate, resulting in a higher electrical conductivity. The increased deposition of polymer on the substrate with the increase of oxidant concentration can be seen on the SEM images of figure 7.
For the morphological characterization of the polymerized samples, SEM technique is widely used in the field ([8], [9], [10]), in order to detect the polymeric film on the substrate, but also to search for signs of the substrate degradation, due to the exposition to oxidant solutions.. In Fig. 7 are presented photos obtained from the SEM analysis of longitudinal fibers of the PEDOT/PES textile samples. It is observed that no damage occurred, even at the higher oxidant concentration of 30 wt%, on the PES fiber. At 15 wt% and 30 wt%, a PEDOT coating is well visible and connecting PES fibers. The 30 wt% samples exhibited globular clusters of the PEDOT polymer [10] in various fiber regions. These samples also exhibit at lower magnification much higher surface roughness. FTIR-ATR spectra of PEDOT/PES samples corresponding to variable oxidant concentration used in the VPP reaction, and of pristine PES sample, are presented in Fig. 8. Several of the peaks obtained can be compared with others already described in literature; such as 959-884 cm-1, which correspond to a C-S-C vibration present in the tiophene ring [11]; 2397-2300 cm-1,related to a substituted C=C bond [9] present in the polymer chain; and at 3033-2847 cm-1, also linked to a C=C vibration [12].
0
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30 35
R/s
q (O
hm)
Oxidant concentration (wt %)
Fig. 6: Influence of the concentration of the oxidant solution in the electrical resistance.
0
50
100
150
200
250
300
350
2 4 6 8 10
5 wt%10 wt%15 wt%30 wt%
I* (m
A)
V (Volt) Fig. 5: V-I* curves of PEDOT/PES for variable oxidant concentration.
53
Conclusions With this method, a good sample resistance, as low as 30 Ohm/sq was obtained using FeCl3 as oxidant [2] and without the need for sample doping [3]. Furthermore, no fiber degradation was detected, even at high oxidant concentration, indicating that polyester fibers are a very good substrate for this method [3] [9] [11]. Another strong point with this method is that it requires a very small amount of monomer for the reaction, when compared to other methods, such as for the example, the in situ polymerization, and still yields good quality in conductive samples. So, with this work, it is now possible to begin new studies with the use of these obtained conducting fabrics on the manufacture of heart-beat sensors. References 1. MacDiarmid, A. G., Nobel lecture: "synthetic metals":
a novel role for organic polymers. Rev. Mod. Phys. 2001, 73, (3), 701-712.
2. Groennendaal, L et al, Adv. Mat., 12, No.7, 2000 3. M. Skrifvars et al, Journal of Applied Polymer
Sciences, 124, 2954-2961, 2012 4. Knittel, M. et al, Synthetic Metals, 159, 1433-1437-
2009 5. Winther-Jensen, B et al, Macromolecules, 37, 12,
4538-4543, 2004 6. Lee, J.Y. et al, Mol. Cryst. Liq. Crys., 405, 161-169,
2003 7. Irwin, M.D. et al, Fibers and Polymers, 12, 7, 904-
910, 2011 8. Oh, K.W. et al, Journal of Applied Polymer Science,
97, 1326-1332, 2005 9. Bashir, T. et al, Polymer Advanced Technology, 23,
611-617, 2010. 10. Jones, W.E. et al, Synthetic Materials, 161, 1159-
1165, 2011 11. Truong, T.L. et al, Thin Solid Films, 516, 6020-6027,
2008 12. Laforge, A. et al, Macromolecules, 43, 4194-4200,
2010
Acknowledgements The authors would like to thank to Centro de Óptica of Universidade da Beira Interior for the SEM imaging.
Fig. 7: SEM images of PES fabrics polymerized with (a) 5 wt%, (b) 15 wt% and (c) 30 wt% FeCl3, with 250x magnification.
Figure 8: FTIR-ATR spectra of pristine and PES fabrics polymerized with 5, 15 and 30 wt% FeCl3
54
Electrochemical techniques for pollution abatement in sanitary landfills
E. Catalão, A. Fernandes, P. Spranger, R. Simões, M.J. Pacheco, L. Ciríaco, A. Lopes
UMTP and Department of Chemistry, University of Beira Interior, Covilhã, Portugal
Abstract
The anodic oxidation of leachate samples collected in a portuguese municipal sanitary landfill was performed using as anode boron-doped diamond material. Two different experimental setups were tested: a batch reactor, with stirring, and a batch up-flow reactor with recirculation. Several different applied current densities were assayed, varying from 30 to 140 mA cm-2. Although faster organic load removal is obtained at higher current density, the increase in current density also leads to a decrease in the current efficiency. However, to have significant removal rates in the organic or ammonium nitrogen, it is necessary to work with higher current densities and these parameters only start to decrease at an appreciable rate after most of the organic load, measured as chemical oxygen demand, is eliminated.
Introduction
Several types of pollutants can be found in sanitary landfill leachates composition, such as heavy metals, organic and inorganic compounds, some of them refractory and toxic [1-2]. The composition and concentration of the pollutants are influenced mainly by the nature of the solid wastes deposited, the climatic conditions and the age of the sanitary landfill [3-4]. One of the major problems in sanitary landfill leachate treatment is its low biodegradability. In fact, biological processes, the most commonly used to treat sanitary landfill leachates, have shown to have limited effectiveness when the ratio between the biological oxygen demand and the chemical oxygen demand, i.e., BOD5/COD ratio, also known as biodegradability index, is lower than 0.5 [3]. Over the past 20 years, there are several studies reporting the application of technologies based on oxidation processes to eliminate colour, reduce the organic load and improve the biodegradability of sanitary landfill leachates [4-6]. Among the most promising electrochemical methods used in the wastewater treatment is the anodic oxidation [7,8]. Deng and Englehardt [6] present an overview of electrochemical oxidation processes used to treat landfill leachates. Although different materials are being used as anodes in the oxidation of persistent pollutants, the best results are obtained with boron-doped diamond (BDD) anodes, due to their unique chemical, electrochemical and structural stabilities that allow their use at high potentials, where most organic pollutants can be oxidized [9]. This way, the aim of this work was to evaluate the application of anodic oxidation, with BDD anode, to treat
leachate from an intermunicipal sanitary landfill, in order to fully fill the requisites that allow its discharge in the municipal wastewater treatment plant. Materials and Methods
Leachate Characterization
The leachate samples used in this study were collected at a Portuguese intermunicipal sanitary landfill site before being submitted to any kind of treatment and the characteristics of the two different samples used are presented in Table 1. Besides the high COD content, the samples A and B have a ratio BOD5/COD of 0.18 and 0.13, respectively, which points to an almost inexistent biodegradability. Also, TKN is very high and most of it is due to ammonium nitrogen. Table 1. Characterization of the raw leachate samples used in this study.
Sample Parameter
A B COD (g/L) 9.2 ± 0.7 8.3 ± 0.4 BOD5 (g/L) 1.7 ± 0.2 1.1 ± 0.4 DOC (g/L) 3.4 ± 0.1 3.3 ± 0.4 TN (g/L) 2.7 ± 0.1 2.7 ± 0.1
TKN (g/L) 2.4 ± 0.1 2.4 ± 0.2 N_NH3 (g/L) 2.2 ± 0.1 2.1 ± 0.3
SS (g/L) 0.7 ± 0.1 -- SD (g/L) 16.6 ± 0.1 --
pH 8.45 ± 0.05 8.21 ± 0.30 Cond. (mS/cm) 28.8 ± 1.2 29.4 ± 0.8
Electrochemical Experiments Anodic oxidation (AO) experiments were conducted in two different cells: cell A, working in batch mode with stirring, having as anode a 10 cm2 BDD plate and as cathode a 10 cm2 stainless steel foil; cell B, working in batch mode with recirculation, having as anode a 20 cm2
BDD plate and as cathode a 20 cm2 stainless steel foil. The volume of raw leachate used in the experiments varied between 200 and 400 mL and assays were started at room temperature (25 2 ºC). However, during the assays the temperature can be naturally raised up to 45 ºC. Several current densities were assayed, ranging from 30 to 140 mA cm-2. A DC power supply GW, Lab DC, model GPS-3030D (0-30 V, 0-3 A) was used in the electrochemical experiments.
55
Analytical Methods Degradation tests were followed by determinations, according standard procedures [10], of COD, BOD5, Dissolved Organic Carbon (DOC), Total Nitrogen (TN), Total Kjeldahl Nitrogen (TKN), Total Ammonia Nitrogen (NH3-N), Suspended Solids (SS) and Dissolved Solids (DS): COD determinations were made using the closed reflux titrimetric method; BOD5 was measured by incubation for 5 days; DOC and TN were measured in a Shimadzu TOC-V CSH analyser and, before their determinations, the samples were filtrated through 0.45
m glass microfiber filters; TKN and NH3-N were determined using a Kjeldatherm block-digestion-system and a Vapodest 20s distillation system, both from Gerhardt. UV-Visible absorbance was measured from 200 to 800 nm using a Shimatzu UV-1800 spectrophotometer. pH was measured with a pH meter HANNA (HI 931400) and conductivity was determined using a conductivity meter Mettler Toledo (SevenEasy S30K).
Results and Discussion
For all the assays performed, the evolution in time of the COD was compared with the evolution of the theoretical COD, CODth, determined according to the following equation [9]:
th 08 . I
COD COD tF . V
(1)
were COD0 is the initial COD, in mg/L, I is the current intensity, in A, F is the Faraday constant, 96485 C/mol, V is the volume of the sample, in m3, and t is the time, in s. Factor 8 relates the molar mass of O2 (32 g) with electrons used in the oxidation of 1 mol of O2 (4 e-). Bias between experimental COD and theoretical COD can be used to predict the current efficiency of the process. Batch with stirring In Figure 1 the results for the COD variation in time for the assays run at different current densities are presented. The figure also includes the theoretical COD, calculated according to equation 1, and we can observe that there is an increase in the bias between the theoretical and the experimental COD values with the current density, with a consequent decrease in the current efficiency. In the assay run at 140 mA cm-2 the anode area used was only 10 cm2 and this is the reason why, apparently, the discrepancy between theoretical and experimental lines are similar to those from the assay run at 70 mA cm-2. In fact, the intensity of the current in both assays, 70 and 140 mA cm-2, is exactly the same and, since the experiments are performed in kinetic (current) control, the current efficiency should also be the same, which, in fact, can be observed in the Figure 1. This result is in agreement with the theoretical approach that, for the high COD of the samples, the assays are being run during most of the time in kinetic control, being the COD removal a function of the electrical charge that is provided to the reacting system.
The absolute removals in the various parameters used to follow the assays, after 6 h, are presented in Table 2. For the assays run between 50 and 100 mA cm-2, and despite the decrease in current efficiency with current density, there is an increase in the removal of all the parameters. Regarding 140 mA cm-2 assay results, and although the previous reasoning that pointed to removals similar to those of the assay run at 70 mA cm-2, there is a big increase in all the parameters related with nitrogen removal, showing that the removal of the different nitrogen forms is very sensitive to the current density, instead of what happens with COD that is sensitive mainly to the electrical charge.
Figure 1. COD decay with time for the assays performed with cell A at different current densities: points – experimental; lines – theoretical. Table 2. Absolute removals after 6 h assay for the experiments run with cell A, in batch with stirring mode at different current densities.
Current density / mA cm-2 Parameter
50 70 100 140
COD / mg L-1 2379 2417 3256 2030 DOC / mg L-1 647 863 969 476 TN / mg L-1 497 677 862 1040 TKN / mg L-1 220 860 950 1148 N_NH3 / mg L-1 527 867 1085 1022 BOD5 / mgO2 L
-1 554 --* --* --* *not determined. Up-flow batch with recirculation The results obtained in the cell B, working in up-flow batch with recirculation mode, are presented in Figure 2 and Table 3. The general conclusions that can be drawn from their observation are, in general, very similar to those gathered with the assays run with cell A. Only the assay run at 50 mA cm-2 shows a COD decay with “irregular” performance that exceeds the tendency line predicted by equation 1. The removals of the nitrogen compounds are very good, although always lower than COD removals.
56
Regarding current efficiencies, they are close to 100 % in the assays performed at lower current densities and, even at 100 mA cm-2, it is very high.
Figure 2. COD decay with time for the assays performed with cell B at different current densities: points – experimental; lines – theoretical. Table 3. Absolute removals after 6 h assay for the experiments run with cell B, working in batch with recirculation mode at different current densities.
Current density / mA cm-2 Parameter
30 50 70 100
COD / mg L-1 4835 8097 6870 7674 DOC / mg L-1 1676 2458 2355 2667 TN / mg L-1 80 777 770 1074 TKN / mg L-1 241 624 1057 1668 N_NH3 / mg L-1 551 711 837 1211 BOD5 / mgO2 L
-1 415 --* --* --* *not determined.
Conclusions From this study the following conclusions can be drawn: Anodic oxidation with BDD anodes can, definitively, be an alternative to treat effluents as difficult as leachates from sanitary landfills are.
For the experimental conditions tested and for both experimental setups, an increase in the current density leads to an increase in the organic load removal rate. However, it also decreases the current efficiency.
For equal current density, COD removal rate is higher when cell B is used, i.e., the hydrodynamic in the cell with recirculation is more effective in the oxidation process.
The removal of the nitrogen compounds increases with current density and their removal is more effective when COD becomes low.
References
1. Öman, C.B., Junestedt, C., 2008. Chemical characterization of landfill leachates – 400 parameters and compounds. Waste Manage. 28, 1876-1891.
2. Eggen, T., Moeder, M., Arukwe, A., 2010. Municipal landfill leachates: A significant source for new and emerging pollutants. Sci. Total Environ. 408, 5147-5157.
3. Renou, S., Givaudan, J.G., Poulain, S., Dirassouyan, F., Moulin, P., 2008. Landfill leachate treatment: Review and opportunity. J. Hazard. Mater. 150, 468-493.
4. Abbas, A.A., Jingsong, G., Ping, L.Z., Ya, P.Y., Al-Rebaki, W.S., 2009. Review on Landfill Leachate Treatments. J. Appl. Sci. Res. 5, 534-545..
5. De Morais, J.L., Zamora, P.P., 2005. Use of advanced oxidation processes to improve the biodegradability of mature landfill leachates. J. Hazard. Mater. 123, 181-186.
6. Deng, Y., Englehardt, J.D., 2007. Electrochemical oxidation for landfill leachate treatment. Waste Manage. 27, 380-388.
7. Anglada, A., Urtiaga, A., Ortiz, I., Mantzavinos, D., Diamadopoulos, E., 2011. Boron-doped diamond anodic treatment of landfill leachate: Evaluation of operating variables and formation of oxidation by-products, Water Res. 45, 828-838.
8. Fernandes, A., Pacheco, M.J., Ciríaco, L., Lopes, A., 2012. Anodic oxidation of a biologically treated leachate on a boron-doped anode, J. Haz. Mat. 199-200, 82-87.
9. Panizza, M., Cerisola, G,, 2009. Direct and mediated anodic oxidation of organic pollutants. Chem. Rev. 109, 6541-6569.
10. Eaton, A., Clesceri, L., Rice, E., Greenberg, A., Franson, M.A., 2005. Standard Methods for Examination of Water and Wastewater, twenty-first ed.. American Public Health Association, Washington, DC.
Acknowledgements
Financial support from FEDER, Programa Operacional Factores de Competitividade – COMPETE, and FCT, for the projects PTDC/AAC- AMB/103112/2008 and PEst-OE/CTM/UI0195/2011 of the MT&P Unit and for the grant awarded to A. Fernandes SFRH/BD/81368/2011.
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DAPP as affinity ligand: support characterization and chromatographic studies with pDNA
C. Caramelo-Nunes1,2, P. Almeida1,2, J.C. Marcos3, C.T. Tomaz1,2
1 CICS-UBI – Health Sciences Research Centre, University of Beira Interior,Av. Infante D. Henrique, 6200-506 Covilhã, Portugal, 2 Department of Chemistry, University of Beira Interior, Rua Marquês d’Ávila e Bolama,
6201-001 Covilhã, Portugal, 3 Center of Chemistry, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
Abstract The intercalator 3,8-diamino-6-phenylphenanthridine (DAPP) was post-grafted onto an epoxy-activated Sepharose matrix to be used as an affinity ligand for the chromatographic separation and purification of supercoiled (sc) plasmid DNA (pDNA). The grafted beaded Sepharose was qualitatively and quantitatively characterized by FT-IR (Fourier Transformed Infrared Spectroscopy), SEM (Scanning Electron Microscopy) and EA (Elemental Analysis). The DAPP affinity interaction with supercoiled, open circular (oc) and linear pDNA isoforms was studied by affinity chromatography. All pDNA isoforms were retained in the column using 10 mM acetate buffer pH 5. Selective elution of oc and linear isoforms was achieved with 0.22 M of sodium chloride in the same buffer. Finally, the sc isoform was eluted increasing the concentration to 0.55 M.
Introduction Small molecules that bind DNA with high specificity can be successfully applied as chromatographic ligands for pDNA purification. The use of affinity and pseudo-affinity ligands can represent an efficient way to overcome many pDNA purification problems.1,2 The high specificity of these molecules is due to the strong interaction between them and the biomolecule of interest, in this case pDNA. This interaction results from a combination of different types of intermolecular binding forces, namely electrostatic, hydrogen bonding, hydrophobic, and van der Waals interactions.3 The minor groove binder berenil was recently applied as ligand for the separation and purification of pDNA from lysate solution impurities.2 The intercalator 3,8-diamino-6-phenylphenanthridine (DAPP) is another promising molecule that shows a strong affinity towards DNA.4,5 DAPP is a planar aromatic system (Fig. 1), where only the phenyl group deviates from the molecular plane. This ethidium like molecule binds to DNA double helix via a non-covalent stacking interaction of its condensed aromatic rings with DNA base pairs, while the phenyl residue gets inserted into the minor groove. The hydrogen bonding between DAPP amino groups and the DNA's
sugar-phosphate backbone plays a less important role in the binding.6 This work reports the development of a new chromatographic support with DAPP as ligand, and its applicability for the specific separation of sc pDNA isoform from the oc and linear isoforms by affinity chromatography.
Materials and Methods Sepharose CL-6B was epoxy-activated according to the method of Sundberg and Porath7 and coupled to DAPP (Fig. 1) according to the process described before.8
Figure 1. Derivatization of epoxi-activated Sepharose with DAPP (unprotonated form).
Dry epoxy-activated Sepharose (3 g) was added to 4 ml of a 2.0 M sodium carbonate solution containing 500 mg of DAPP. After swirling for 16 h at 70ºC, the derivatized Sepharose was washed with large volumes of deionised water and 70% ethanol solution to remove the excess of ligand and sodium carbonate. The derivatized gel was stored at 4ºC in deionised water. FT-IR spectra of the DAPP derivatized gel and of epoxy-activated Sepharose (with no DAPP) were acquired on a Thermo Scientific Nicolet iS10 FT-IR spectrometer (Thermo Scientific, Waltham, MA). Spectra were recorded at 4 cm-1 (128 scans) over the 400-4000 cm-1 range without baseline corrections. Bands were given in cm-1. The microanalyses of both DAPP derivatized gel and epoxy-activated Sepharose were performed in triplicate using a Carlo-Erba CHNS-O AE-1108 Elemental Analyser (Thermo Scientific, Waltham, MA). SEM images of both matrices were acquired in a Hitachi S-2700 with a UHV Dewar detector (Rontec EDX) (Tokyo, Japan). The samples were magnified 150, 450 and 4000x. Before all analyses, the
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samples were well-dried at 50ºC, in the presence of phosphorus pentoxide. Escherichia coli DH5 strain harbouring 6.05 Kbp plasmid pVax1-LacZ (Invitrogene, Carlsband, CA, USA) was cultured as previously described.8 Plasmid DNA was purified using the Qiagen plasmid midi kit (Hilden, Germany) according to the manufacturer’s instructions. Linear plasmid isoform sample was prepared by enzymatic digestion of the purified pDNA with the Hind III enzyme for 2 hours, at 37ºC. Plasmid quantification was made by measuring the absorbance at 260 nm. A 10 cm x 10 mm column (Amersham Biosciences, Uppsala, Sweden) was packed with 2.5 mL DAPP-derivatized gel (Fig. 1) and connected to a Fast Protein Liquid Chromatography (FPLC) system (Amersham Biosciences, Uppsala, Sweden). 25 μL of plasmid samples (600 μg/mL of a mixture of oc, linear and sc isoforms) were injected at a flow rate of 1 mL/min with 10 mM acetate buffer, pH 5. The species with lower affinity for the derivatized support were eluted with 0.22M NaCl in the same buffer. The elution of strongly bound species was achieved with a second isocratic elution step by increasing the NaCl concentration to 0.55 M. The absorbance was monitored continuously at 280 nm. Fractions were pooled according to the chromatogram obtained and analyzed by gel electrophoresis (110 V) using 1% agarose gel in TAE buffer (40 mM Tris base, 20 mM acetic acid, and 1 mM EDTA at pH 8.0) with 0.5 μg/ml ethidium bromide. The gels were visualized in a UVITEC Cambridge system (UVITEC Limited, Cambridge, UK).
Results and Discussion Following our previous work2,8 with berenil as an immobilized pseudo-affinity ligand, we developed an affinity support using the intercalator DAPP as ligand and tested it for the specific separation of supercoiled pDNA isoform. DAPP was coupled onto an epoxy-activated Sepharose matrix using a relatively mild curing method with a 1:6 ratio of ligand : Sepharose. The resulting support (Fig. 1) was then characterized by EA, SEM (Fig. 2) and FT-IR spectroscopy to confirm the presence of the covalent bond between DAPP and Sepharose and to quantify the bonded ligand. The amount of DAPP bonded to Sepharose (Q, mmol DAPP/g derivatized Sepharose) was determined by EA using equation (1), where %N is the nitrogen percentage, assuming that all of the nitrogen present in the sample comes exclusively from DAPP.9
Q = (mmol DAPP/g derivatized Sepharose) (1)
The determined amount of DAPP bonded to Sepharose was 0.15 mmol DAPP/g derivatized Sepharose (42.8 mg DAPP/g derivatized Sepharose). The relatively low ligand density obtained could be favorable to pDNA binding. A very dense layer of immobilized ligands can hinder the
access of an isolated ligand molecule onto the buried binding sites of pDNA and therefore prevent the recognition between them.3,10,11 The amount of nitrogen was also determined in a sample of beaded Sepharose submitted to the same curing method but without DAPP. In this case, the %N was below the detection level (0.07%). SEM micrographs of 150, 450 and 4000x magnifications performed on epoxy-activated Sepharose samples before and after the immobilization process (Fig. 2), did not present any significant differences between them.
Figure 2. Representative SEM micrographs of Sepharose beads at 150x (A), 450x (B), and 4000x (C) magnification. Top row: epoxy-activated Sepharose with no DAPP and bottom row: DAPP-Sepharose matrix. This observation shows the maintenance of the original Sepharose morphology and therefore, its physical properties after been subjected to the curing process. These results are crucial to DAPP-Sepharose application as a chromatographic support. Comparing the spectrum for DAPP-Sepharose with the one for epoxy-Sepharose without ligand (results not shown), the first revealed a new band at 1621 cm-1. This band could be the result of the amines N-H bending band or the in-plane skeletal vibrations of DAPP aromatic rings. The assignment is complicated because they both occur in the same region12 however, since this band is absent in the epoxy-Sepharose spectrum it appears as strong qualitative evidence that DAPP was indeed coupled to the Sepharose matrix. Initial chromatographic experiments were performed to find the buffer conditions to achieve total retention of pDNA molecules on the DAPP-Sepharose column (Fig. 3). After achieving total retention of the injected sample using acetate buffer with a pH value of 5, a selective elution of oc and linear isoforms was achieved (peak 1/lane 1 of Fig.3) by adding sodium chloride up to a concentration of 0.22 M. Increasing the sodium chloride concentration to 0.55M led to the elution of the sc isoform (peak 2/lane 2 of Fig.3).
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Figure 3. Chromatographic separation of pDNA isoforms on DAPP-Sepharose and agarose gel electrophoresis of the peak fractions. Lane pDNA: sample of pDNA injected onto the column (mixture of oc and sc and linear isoforms). Lane 1: oc and linear pDNA fraction collected from peak 1. Lane 2: sc pDNA fraction collected from peak 2. The electrophoresis results (Fig. 3) showed that oc and linear isoforms were not detected in the sc fraction (lane 2), which indicates that the sc pDNA amount in peak 2 is near 100%. These results show that the DAPP-Sepharose matrix has a great affinity towards the sc pDNA isoform. The fact that pDNA is completely retained in the column without any salt in the binding buffer indicates the presence of strong interactions with charged phosphate groups of the DNA backbone.13 However, phosphate and sugar groups are equally exposed in all isoforms. Therefore, the observed differences in retention may be due to the higher exposure of the bases of sc isoform, consequence of deformations induced by torsional strain.14
Conclusions The present work describes the development of a new affinity support for pDNA purification. The DAPP-Sepharose support was prepared using a relatively mild curing method and with a 1:6 weight ratio of ligand:Sepharose. This resulted in a ligand density of 0.15 mmol DAPP/g derivatized Sepharose. Additionally, FT-IR pointed to the presence of DAPP’s aromatic rings and/or amines in the support, which shows the existence of the covalent bond between Sepharose and DAPP. SEM analysis showed the preservation of the original beaded Sepharose morphology and therefore its mechanical properties after the immobilization process, which is crucial to its application as a chromatographic support. The chromatographic results showed that the DAPP-Sepharose affinity support can be successfully applied in the selective separation of sc pDNA isoform from the other less active isoforms. This is achieved using small amounts of salt in the eluent, favouring the economic and environmental sustainability.
References 1. Sousa, F., Prazeres, D.M. and Queiroz, J.A., Trends
Biotechnol., 26, 518, 2008. 2. Caramelo-Nunes, C., Gabriel,M.F., AlmeidaP., Marcos,
J.C. and Tomaz, C.T., J. Chromatogr. B, 904, 81, 2012. 3. Jones, K., Encyclopedia of Separation Science,
Academic Press Inc., Vol. 1, 2000. 4. Shi, X. and Macgregor, R.B. Jr., J. Phys. Chem. B, 111,
3321, 2007. 5. Misra, V.K. and Honig, B., Proc. Natl. Acad. Sci. USA,
92, 4691, 1995. 6. Kubar, T., Hanus, M., Ryjácek, F. and Hobza, P.,
Chemistry, 12, 280. 2005. 7. Sundberg, L. and Porath, J., J. Chromatogr., 90, 87,
1974. 8. Caramelo-Nunes, C., Tente, T., Almeida, P., Marcos,
J.C. and Tomaz, C.T., Anal. Biochem., 412, 153, 2011. 9. Silva, A., Boto, R.E.F., El-Shishtawy, R.M. and
Almeida, P., European Polymer Journal, 42, 2270, 2006. 10. Labrou, N.E., J. Chromatogr. B, 790, 67, 2003. 11. Murza, A. and Fernández-Lafuente, R. and Guisán,
J.M., J. Chromatogr. B,740, 211, 2000. 12. Vogel, A.I., Vogel's textbook of practical organic
chemistry, 5th Edition, Longman Scientific & Technical, 1989.
13. Sousa, F., Matos, T., Prazeres, D.M.F. and Queiroz, J.A., Anal. Biochem., 374, 432, 2008.
14. Sousa, F., Tomaz, C.T., Prazeres, D.M.F. and Queiroz, J.A., Anal. Biochem., 343, 183, 2005.
Acknowledgements This work was supported by FCT, the Portuguese Foundation for Science and Technology PTDC/QUI-QUI/100896/2008 and FCT program COMPETE (PEst-C/SAU/UI0709/2011). C. Caramelo-Nunes acknowledges a fellowship (SFRH/BD/64918/2009) from FCT.
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Effect of continuous thermal stabilization process on thermal transitions and mechanical properties of a false-twist textured Polylactide multifilament
A. M. Manich¹, M. Martí¹, J. Carilla¹, B. Baena¹, D. Cayuela2
¹IQAC-CSIC, Barcelona (Spain), ²INTEXTER-UPC, Terrassa (Spain)
Abstract
A polylactide (PLA) multifilament false-twist textured at 150ºC being stretched 1.35, has been stabilized using a proptotype chamber for continuous stabilization under different conditions of draw ratio and temperature. The effect of draw ratio and temperature on thermal transitions and mechanical properties of the filaments has been studied. The initial modulus, yield strain and breaking stress increases with crystallinity, while yield stress and breaking strain show a significant relationship with melting temperature that seems to reflect the increase in size/perfection/orientation of crystals during stabilization.
Introduction Polylactide (PLA) is a biodegradable and compostable polymer obtained from annually renewable resources. Several researchers, confirming that this polymer has significant commercial potential as a textile fibre [1], have studied its physical properties and structure. PLA fibres are normally produced by melt extrusion. The effect of draw ratio and draw roll temperature on the orientation, crystallinity and mechanical properties of spun filaments have been studied [2, 3]. The application of false-twist texturing to PLA multifilament shows some limitations to give adequate properties for textile processing. The effect of texturing variables on its structure [4] and the application of some stabilization treatments to improve the mechanical properties [5], the relaxation behaviour [6], and the design of a prototype for continuous stabilization process [7] have been the main topics considered up to now. The main objective of this work is to study the influence of draw ratio and temperature of stabilization on the thermal transitions and mechanical properties of the stabilized filaments.
Materials and Methods
A 167dtex/68 polylactide filament POY yarn false-twist textured at 150ºC and 1.35 stretched supplied by Angles Textil S.A., was thermally stabilized passing through the stabilization chamber plot in Figure 1 at 50m/min, at different conditions of draw ratio and temperature. Table 1 shows the references of the samples and the conditions of draw ratio and temperature applied to them.
Differential Scanning Calorimetry (DSC): The intensity of the thermal events post glass transition (relaxation, cold crystallisation and melting) were determined in a Mettler
Toledo DSC-823 apparatus. Filaments were cut into very short lengths and duplicated samples of approximately 6
m punched pans to guarantee good contact with the DSC sensor. DSC curves were obtained under the following operating conditions: initial temperature 30ºC, final temperature 250ºC, heating rate 10ºC/min and nitrogen purging gas 35 ml/min.
Figure 1 Prototype for continuous stabilization of PLA.
Table 1 Reference, draw ratio DR and stabilization temperature ST applied to a 167dtex/68 PLA textured filament.
Ref DR ST Ref DR ST A0D A1D A2D A3D B1D
Original 1.07 1.07 1.07 1.14
- 90ºC 100ºC 110ºC 90ºC
B2D B3D C1D C2D C3D
1.14 1.14 1.21 1.21 1.21
100ºC 110ºC 90ºC 100ºC 110ºC
The DSC curve (Figure 2) shows the endo and exothermic effects, below and above the base line and the energy and temperatures involved in relaxation, cold crystallisation and melting processes were measured. By comparing the melting enthalpy of the sample with the melting enthalpy of a 100% crystalline polylactide (93.6 J/g), the percentage of crystallinity (XDSC) was calculated through the equation XDSC
Tensile properties: Ten specimens of 100 mm in gauge length were tested after conditioning in a standard atmosphere for 48 h. Specimens were subjected to tensile
61
testing at 60%/min according to the ASTM D2101 Standard. The Stress/strain curve (Figure 3) yields the initial modulus IM (cN/tex), the stress Y [cN/tex] and strain Y [%] at yield, and the
Figure 2 DSC plot of PLA multifilament from 30 to 250ºC at 10ºC/min. Punched pan. Nitrogen purging gas 35 mL/min.
Figure 3 Stress/strain curve of PLA multifilaments.
Results and Discussion
Results of thermal transitions and crystallinity measured by differential scanning calorimetry are shown in Table 2.
Table 2 Enthalpies and peak temperatures of relaxation and cold crystallisation ( , Tr, , Tcc), melting enthalpy , onset temperature of melting Tm and crystallinity of the samples according to references of textured and stabilized yarns (see Table 1) Ref.
J/g Tr ºC
J/g
Tcc ºC
J/g
Tm ºC
XDSC
% A0D A1D A2D A3D B1D B2D B3D C1D C2D C3D
5,70 6,33 2,29 1,33 5,62 2,79 0,81 3,34 2,80 0,84
68,13 65,74 64,09 65,18 65,73 65,23 65,82 66,07 65,49 67,16
8,54 10,87
4,88 0,22 9,76 5,00 0,41 7,25 2,43 0,10
72,66 71,02 72,46 68,66 71,18 73,12 70,57 73,57 74,10 71,92
42,13 49,72 48,75 47,56 47,06 47,28 47,82 47,17 49,18 49,21
159,85 159,78 159,89 159,34 160,23 159,55 160,25 160,71 160,33 160,01
35,85 41,47 46,82 50,52 39,80 45,12 50,60 42,61 49,89 52,41
Results of tensile testing are shown in Table 3.
Table 3 Initial modulus, stress and strain at yield and stress and strain at breaking of the samples according to references of textured and stabilized yarns (see Table 1) Ref. IM
cN/tex Y
cN/tex Y
%
cN/tex
% A0D A1D A2D A3D B1D B2D B3D C1D C2D C3D
310,6 314,9 391,5 434,1 384,0 418,8 454,5 428,1 437,0 468,3
9,15 9,53 9,81 8,82 10,74 11,37 9,53 12,29 11,59 10,18
5,15 5,01 3,40 2,67 4,01 3,76 2,99 4,36 4,01 2,99
17,37 18,63 19,12 20,58 19,86 22,44 22,83 20,33 23,30 25,08
30,73 31,07 37,12 38,42 28,34 30,45 31,90 24,83 26,41 29,44
The application of factorial analysis to the results of thermal transitions enabled us to identify the two main important factors that accounts for the maximum differences between the samples (Figure 4).
Figure 4 Factorial analysis of the thermal transitions.
The first factor mainly related with crystallinity explains the 51% of the variability between the samples and illustrates the very high correlations between relaxation and cold crystallisation energies and crystallinity. The endo- and exothermic peaks post Tg, attributed by Stoclet et al. [8] to the partial melting and recrystallisation of the meso-phase, tend to disappear with temperature increase. The lower the meso-phase the higher the crystallinity of the sample. The second factor is based on melting and cold crystallisation temperatures and seems to reflect the size, perfection and orientation of crystals [9]. The higher the melting temperature the greater the overall molecular
[10]. It accounts for a 24% of the variability.
The influence of stabilization variables on each response y will be analysed by the percentage of variation induced by stabilization on the values of the original textured sample: y = b0 ibi xi ijbij xi xj x1 temperature and x2 draw ratio of stabilization. The application of the Analysis of Variance enabled us to remove the non-significant variables from the model to
. Results are discussed using the surface responses that illustrate the
62
effect of stabilization on them. For the sake of brevity, regression equations are not given.
The effect of stabilization on crystallinity is depicted in Figure 5. Its increase is mainly favoured by temperature, although when draw ratio exceeds 1.12 the higher the draw ratio (orientation) the greater the crystallinity.
Figure 5 Variation in crystallinity according to temperature and draw ratio of stabilization. R²= 96.99%.
The effect of stabilization on melting temperature is shown in Figure 6. The higher the draw ratio (orientation), the greater the melting temperature that is related with a higher size and perfection of crystals.
Figure 6 Variation in melting temperature according to temperature and draw ratio of stabilization. R²= 62.75%.
Mechanical properties:
The positive effect of temperature on the initial modulus decreases with the increase in draw ratio (Figure 7). Orientation favours the initial modulus. The highly significant negative correlation with relaxation enthalpy (r=-0.8897) reveals that the lower the meso-phase (higher crystallinity) the greater the initial modulus.
Yield stress is mainly dependent on the orientation as regards the high influence of draw ratio on it (Figure 8).
Figure 7 Variation in the Initial Modulus according to temperature and draw ratio of stabilization. R²= 97.70%.
The correlation with Tcc (r= 0.7457) and Tm (r= 0.6335) confirms it. When temperature exceeds 100ºC yield stress decreases due to its effect on crystallinity.
Figure 8 Variation in Yield Tenacity according to temperature
and draw ratio of stabilization. R²= 96.70%.
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Figure 9 Variation in Yield Strain according to temperature and draw ratio of stabilization. R²= 87.98%.
Yield strain is mainly influenced by temperature. The correlation with relaxation enthalpy (r= 0.8987) reveals that yield strain decreases with crystallinity (Fig. 9).
Figure 10 Variation in Breaking stress according to temperature and draw ratio of stabilization. R²= 95.13%.
The effect of temperature on breaking tenacity increases with orientation (Figure 10) that also positively affects it. The high correlation with crystallinity (r= 0.8089) points out the dependence of tenacity on crystallinity.
Figure 11 Variation in Breaking strain according to temperature and draw ratio of stabilization. R²= 93.87%.
Breaking strain greatly decreases with orientation while the effect of temperature makes it to ascend. The negative correlation with Tm (r=-0.756) point out the predominant effect of orientation on this parameter.
Conclusions
Stabilization affects crystallinity and the size and perfection of crystals. Crystallinity is mainly favoured by temperature although high draw ratio levels improve it. The size and perfection of crystals related with melting
temperature is improved by draw ratio. Initial modulus, yield strain and breaking stress show good relationship with crystallinity, while yield stress and breaking strain are mainly related with orientation and the size and perfection of crystals. References 1. Farrington, D.W.; Lunt, J.; Davies, S.; Blackburn, S.R.:
Poly(lactic acid) fibers, In Biodegradable and sustainable fibres. Woodhead Publishing Limited, ISBN 13:978-1-85573-916-1, 2005
2. Solarski S., Ferreira M., Devaux E. Thermal and mechanical characteristics of polylactide filaments drawn at different temperatures. J Text Inst. 98: 22736, 2007.
3. Manich A. M., Carilla J., Miguel R. A. L., Lucas J. M., Franco F. G. F., Montero L. A., Cayuela D., Thermal transitions of polylactide false-twist textured multifilaments determined by DSC and TMA, J Therm Anal Calorim, 99, 3, 723-731, 2010.
4. Cayuela D., Montero L., Díaz J., Algaba I and Manich A.M. Microstructure variations of Polylactide Fibres with Texturing conditions, Text Res J. 82, 19, 1996-2005, 2012.
5. Manich A.M., Carilla, J., Miguel R.A.L., Baena B., Lucas J., Martí M. and Cayuela D., Differential Scanning Calorimetry and Elasticity of Textured, Heat Set and Mechanical Strained Polylactide Multifilaments, Fib Text East Eur, 89, 6, 22-27, 2011.
6. Manich A. M., Miguel R., Lucas J., Franco F., Baena B., Carilla, J., Montero L., Cayuela D., Texturing, stretching and relaxation behaviour of polylactide multifilament yarns, Text. Res. J., 81(17) 1788-1795, 2011.
7. Manich A.M., Carilla J., López-Santana D., Baena B., Riba M, Prieto R, Montero L. and Cayuela D. Effect of continuous post-setting on crystallinity ant thermomechanical behaviour of False-Twist Textured Polylactide multifilaments, Simpósio 2011 Unidade de Materiais Têxteis e Papeleiros, Covilhã, Universidade da Beira Interior, Livro de Actas, págs 34-37, 2011.
8. Stoclet G., Seguela R., Lefebvre J.M. and Rochas C., New insights on the strain-induced mesophase of poly (D,L-lactide): in situ WAXS and DSC study of the thermomechanical stability. Macromol 43:7228-7237, 2010
9. Mukhopadhyay S K. Nature and Mechanisms of Heat-setting of Fibres (Chapter 6), in Advances in Fibre
Institute, Manchester, 1992 10. Pan p., Kai W., Zhu B., Dong T. and Inoue Y.,
Polymorphous crystallization and multiple melting behaviour of poly(L-lactide): molecular weight dependence. Macromol 40:6898-6905, 2007.
Acknowledgements
Authors are indebted to the Spanish project MAT2010-20324-C02-02 for funding. They also express their
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gratitude to the company Angles Textil, S.A. (ANTEX) for their generous help in providing and preparing the textured samples.
65
Estratégias e práticas sustentáveis na cadeia têxtil
Madalena Pereira1 , R.Miguel1 , J.Lucas1, M.Santos Silva1, I.Trindade1 1Departamento de Ciência e Tecnologia Têxteis, University of Beira Interior
1Unidade de Investigação dos Materiais Têxteis e Papeleiros Pólo I Rua Marquês d'Ávila e Bolama, 6201-001 Covilhã, Portugal
Tel: +351275319700, Fax: +351275319768
Abstract Na atualidade as empresas da cadeia têxtil desenvolvem e reformulam estratégias ambientais e sociais. Estas estratégias desenvolvem-se ao longo da cadeia, tendo em conta o impacto social e ambiental dos seus colaboradores, parceiros e sociedade em geral. A atuação no ciclo de vida dos produtos é feita através da minimização do impacto ambiental do produto durante todo o ciclo de vida, desde as matérias primas, produção, utilização, reutilização, transporte, reciclagem e eliminação. No entanto, a cadeia têxtil de um produto nos dias de hoje, é repartida por várias localizações e parceiros, o que torna complexo a definição de uma estratégia global para o produto final. A aplicação das boas práticas têm surgido no mercado, podendo estas contribuir como exemplo para os vários playeres da cadeia. Assim, este trabalho pretende apresentar exemplos da cadeia têxtil e as respectivas estratégias definidas no âmbito da sustentabilidade bem como as boas práticas. O caso apresentado recai no grupo PPR, por incluir marcas de luxo e desporto, pela sua dimensão e complexidade. Outros casos serão aqui apresentados como exemplos de utilização de boas práticas na cadeia têxtil. Este trabalho pretende sensibilizar e exemplificar às empresas da cadeia têxtil as boas práticas associadas à sustentabilidade. A legislação e sua aplicação em matéria de sustentabilidade é um dos factores que poderá contribuir para a resolução de um sistema complexo como o da cadeia têxtil.
Introdução
A indústria da moda1 representa um importante player na economia global, quer na percentagem de mão de obra empregue, quer no volume de negócios a ela associada. Atualmente a UE possui cerca de 850.000 empresas, e emprega 5 milhões de pessoas na EU [1]. Em Portugal a indústria produtiva da cadeia têxtil emprega em 2012 cerca de 150.000 pessoas e exportou em 2011 quatro mil milhões de euros (ATP, 2012) [2]. A contribuição da indústria da moda na União Europeia representa 3% do produto interno bruto[1]. A globalização exige a gestão da
1 A indústria da moda incluí: design de moda, produção de matérias primas a bens de moda (têxteis, vestuário, calçado, pele, joalharia e acessórios) e também a sua distribuição e retalho ao consumidor final
cadeia de fornecimento não só pelas questões económicas mas também pelas condições de trabalho justas e um sistema de produção amigo do ambiente [3]. Assim, os objectivos da gestão da cadeia de fornecimento envolvem estratégias de desenvolvimento sustentáveis assentes em três pilares e dimensões: económico, social e ambiental [4,5,6].
A gestão da cadeia de fornecimento feita de uma forma sustentável tornou-se uma crescente preocupação para as empresas de diferentes dimensões e de vários sectores. Cumprir as normas ambientais e sociais ao longo de todas as fases da cadeia garante o desempenho mínimo exigido associado à sustentabilidade seja alcançado pelas empresas. Esta abordagem mais proactiva tenta responder à pressão dos governos, consumidores, organizações não governamentais (ONGs) e mídea. [7, 8].
Uma das falhas encontradas pelos investigadores no meio académico reverte-se com a necessidade do aumento de cooperação ao longo da cadeia de fornecimento para que os objectivos de sustentabilidade sejam alcançados e o desenvolvimento de políticas sociais cooperativas (CRS) [6]. Neste sentido a UE definiu um conjunto de medidas, nomeadamente a política de produtos integrada, que incentiva as empresas a desenvolver produtos tendo em conta o seu impacto ambiental durante o seu ciclo de vida, desde o fabrico à sua eliminação. O plano de ação para um consumo e produção sustentáveis e uma política industrial sustentável, foi definido num quadro dinâmico para melhorar o desempenho energético e ambiental dos produtos e incentivar a utilização destes produtos pelo consumidor [9].
As estratégias e políticas definidas para o ciclo de vida dos produtos pretendem: (1) pensar em termos de ciclo de vida; (2) desenvolver ferramentas para avaliação do ciclo de vida nas PME Es); e (3) criação de uma política de produtos integrada2. Outras políticas e instrumentos tais como: rótulo ecológico; sistemas de eco-gestão e auditoria ambiental; plano de ação para a eco-inovação; iniciativas mercados-piloto; plano de ação para um consumo e produção sustentáveis e uma política industrial sustentável; small business act; prémios europeus do ambiente para empresas e formação e
2 http://europa.eu/youreurope/business/doing-business-responsibly/taking-sustainability-further/index_pt.htm
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desenvolvimento profissional, fazem também parte das políticas lançadas pela UE nos últimos anos2. Uma das medidas mais desenvolvida pela UE nos últimos anos foi a definição dos critérios para aplicação da Eco-label na cadeia têxtil, que promove a produção e o consumo de produtos com redução no impacto ambiental ao longo da cadeia de fornecimento. A sua regulação foi conduzida em 2010 com o regulamento (EC) No 66/2010 através da política europeia PPE Public Procurement for a better Environment3
Outro exemplo de política desenvolvida e em revisão na atualidade reveste-se com a exploração de todo o potencial ecológico da indústria, através de sistema de gestão ambiental, como o sistema Comunitário de Ecogestão e Auditoria (EMAS) com o novo regulamento (CE) Nº 1221/2009, tratando-se de um sistema voluntário que ajuda a optimizar a produção e processos de trabalho, permitindo a utilização mais eficiente dos recursos [9]. Também a nível produtivo surge a regulamentação para iniciativas de responsabilidade social cooperativa (CRS). A este nível houve um aumento de 69 em 2007 para 700 i Business Social Compliance Initiativepublicou relatórios de sustentabilidade em conformidade com as orientações da Global Reporting Initiative, aumentou de 270 em 2006 para mais de 850 em 2011[10]. As ações multiplicam-se a favor da criação de mercados globais para produtos sustentáveis e os grandes grupos da cadeia criam os seus departamentos de sustentabilidade apoiados nas estratégias definidas pela EU para 2020 e 2050.
A sustentabilidade na cadeia têxtil e seu desempenho
O impacto ambiental da cadeia têxtil onde se inclui a moda representa valores muito significativos, tendo em conta o volume global associado, com cerca de 9,3% do emprego total e 4% da exportação global [11]. O processo de produção, em particular das operações de tingimento, branqueamentos e acabamento, utiliza um elevado número de componentes químicos, recursos naturais e elevado impacto ambiental [12] . Para além disso, o uso de fibras como o algodão, lã e fibras sintéticas, necessita de elevadas quantidades de água e pesticidas, enquanto as fibras sintéticas provêm de recursos não renováveis e requerem elevados recursos energéticos para a sua produção. Também com a deslocalização de fases de produção para países terceiros e seu consumo posterior na UE e USA, provoca impacto ambiental devido ao transporte e logística na cadeia.
Nos dias de hoje a gestão da cadeia têxtil alterou-se substancialmente nos anos 90, de localização, transformando-se num modelo de deslocalização com subcontratação de várias partes do processo produtivo
3 Comunicação COM(2008) 400
(desde a tecelagem, tinturaria, acabamentos e confecção) (figura 1) [12].
A evolução das políticas e práticas de sustentabilidade na cadeia têxtil progride desde os anos oitenta pioneira em nichos de retalhistas para ao longo dos anos 90 em retalhistas mainstream, nomeadamente na Alemanha e na Suíça e com a criação de marcas sustentáveis como é o caso da Pantagónia, Tejin e Weliman. Em 2010 surgem as primeiras linhas sustentáveis em cadeias de retalho como a H&M; M&S, C&A, Carrefour e Ikea; produtores especialistas (TDV) e produtores de fibras fora da União Europeia (figura 1).
Também nos anos 2000 surgem as primeiras organizações não governamentais e empresas de certificação, como o caso da Fairtrade (fundação e certificação, cujo o objectivo é a criação de vantagens competitivas para os produtores e trabalhadores de países em desenvolvimento; a marca foi criada como um registo de certificação), Global Recycle Standard (promove e incentiva as empresas a produzir e a vender produtos com materiais reciclados), Global Organic Textiles Standard (promove o desenvolvimento, implementação, verificação, proteção e promoção do algodão ecológico com emissão de certificados GOTS), entre outras [13].
Figura 1 Evolução das práticas sustentáveis na cadeia de fornecimento.
Assim, neste novo contexto a gestão da cadeia de fornecimento necessita de alterações quer a nível da competitividade quer ao nível da responsabilidade ambiental, sendo que a indústria necessita de trabalhar com maior proximidade com os seus parceiros.
Vários investigadores surgem com estudos e propostas de boas práticas de sustentabilidade na cadeia têxtil. Cianato e al. [14, 15] refere também a necessidade de investigar os
greencadeia têxtil; (2) identificar as melhores práticas para aumentar da sustentabilidade ambiental, e (c) os resultados a nível do desempenho em sustentabilidade medido pelos indicadores chave (KPls) [14].
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Figura 2 Modelo de Cianato e al. [13].para a medição do desempenho na cadeia têxtil em termos de sustentabilidade.
Na sua investigação considerou vários indicadores da cadeia importantes para a medição do desempenho em termos de sustentabilidade, baseando-se no modelo de
14].
Ao nível dos players internos, relacionou os objectivos da eficiência (redução de custos) e outros factores específicos da empresa (valores cooperativos da direção e objectivos de responsabilidade cooperativa). Os players do mercado relacionam-se com os requisitos de sustentabilidade ambiental dos consumidores; podendo estes ser clientes industriais ou consumidores finais. No contexto refere-se aos requisitos a nível da regulação atual e futura.
Nas práticas Cianato e al. [14], divide estas em três grupos: produto, processo e gestão da cadeia de fornecimento. A nível de produto identifica todas as decisões relacionadas com as características do produto, tais como a escolha de materiais, o desenvolvimento de outras componentes e da embalagem. A nível do processo inclui o desenvolvimento dos processos de produção, desde as matérias primas ao produto acabado, incluindo apenas os processos internos da empresa. Finalmente na gestão da cadeia de fornecimento foram incluídos as decisões relacionadas com o in-sourcing e outsourcing, canais logísticos, fornecedores, clientes e relacionamento com os diferentes atores da cadeia.
Na medição do desempenho foi considerados os critérios ambientais mais importantes que as empresas usam para melhorar ou implementa greennos Key Performance Indicators, que assumem vários modelos. O modelo GRI foi o selecionado pelo autor que inclui nove indicadores: matérias primas; energia, água, biodiversidade, emissões, produtos e serviços; conformidades; transportes e integração do modelo de negocio [14]. Relativamente às empresas presentes no mercado para a certificação e divulgação dos critérios de medida para a sustentabilidade, encontra-se diferentes tipos e diferente número de indicadores em função dos objetivos de cada entidade. Atualmente um variado número de rótulos de certificação surgem no mercado com informação variada para o consumidor.
O rótulo verde e certificações na cadeia têxtil
O rótulo de um produto é hoje considerado essencial para o sucesso das políticas da sustentabilidade e como forma de informar o consumidor de uma forma credível. A nível da divulgação da rotulagem dos produtos e processos um conjunto de iniciativas surgiram no mercados nos últimos dez anos. Assim destacam-se algumas empresas como Better Cotton Inicitive, Global Recycling Standart, Bluesign; Eco-Index, Made By, Business Social Compilance Iniciative, entre outras. O nível de aceitação pelo mercado dos rótulos e certificados das várias entidades varia, bem como os vários requisitos regulados (energia, água, químicos, emissões, sistemas de gestão, saúde e segurança, políticas ambientais, responsabilidade social, auditorias e validação, implementação e rotulagem). Bluesign Standart, Gots, ISO140001:2004 e OEKO-TEX 100 são os que apresentam um nível mais elevado de aceitação pelo mercado, segundo a empresa sem fins lucrativos Made-By (figura 3) [13].
ISO 14001:2004 Figura 3 - Variedade de rótulos associados às boas práticas de sustentabilidade. No que diz respeito ao rótulo ecolabel, este informa o consumidor dos seguintes pontos: (1) a utilização de substâncias nocivas ao meio ambiente; (2) a utilização de substâncias nocivas à saúde; (3) redução da poluição de ar e água; (4) diminuição da resistência durante a lavagem e secagem; solidez da cor à transpiração, lavagem, fricção em molhado e seco e exposição à luz; (5) substâncias excluídas ou limitadas; (6) a não presença de fibras minerais, fibras de vidro; fibras metálicas; fibras de carbono e de outras fibras inorgânicas; (7) limitações de certos pesticidas; (8) a não existência de pigmentos à base de chumbo; (9) utilização limitada de zinco e cobre; (10) a não presença de metais pesados e de formaldeído; (11) a não existência de corantes azoicos; (12) a não existência de corantes classificados como cancerígenas, mutagênicos, tóxicos para a fertilidade; (13) a não existências de plastificantes ou solventes GPP destacados pelo SPC/IP e no roadmap 2020, onde a comissão
green
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práticas de contratação das autoridades públicas (figura 4) [13].
Figura 4 - categorias de Ecolabel para as três categorias associadas à cadeia têxtil: (1) calçado; (2) produtos têxteis e vestuário; (3) soft (Têxtiles) floor coverings.
Do conjunto das três categorias da cadeia têxtil e calçado existentes de ecolabel, 1421 empresas estão registadas; das quais 1360 de produtos têxteis e vestuário e 61 empresas de calçado4.
Quer a nível de ecolabel quer a nível de outras iniciativas é necessário conhecer os indicadores de atuação no mercado de cada uma delas (tabela 1 e 2). Da análise da
Tabela um e dois pode-se concluir que o rótulo dos países Nórdicos é o mais abrangente seguido da Ecolabel em termos de comtemplar o maior número de indicadores.
Tabela 1 Indicadores associados à sustentabilidade comtemplados nos diferentes rótulos.
O nível de certificação atingida destaca-se em termos de número de indicadores a ecoindex e a certificação oko-tex 1000. No entanto se uma empresa pretende apenas a certificação a nível produtivos e em termos de restrições das substâncias químicas a bluesign será a mais indicada.
4 http://ec.europa.eu/ecat/
Tabela 2 - Indicadores associados à sustentabilidade comtemplados nas diferentes entidades no mercado.
Outras formas de classificação surgem dos trabalhos de investigadores, nomeadamente da equipa de trabalho da comissão europeia na área do rótulo ecológico que em 2012 se reúne para a sua reformulação.
A organização sem fins lucrativos MADE-BY, com o objectivo de melhorar o meio ambiente e as condições sociais da indústria têxtil, desenvolveu uma classificação que está associada às marcas de moda que pretendem divulgar os rótulos da tabela 3 a que aderiram e consequentemente as suas práticas ambientais. Um número de 27 marcas já aderiram a esta iniciativa.
Tabela 3 Indicadores associados à sustentabilidade comtemplados nos diferentes rótulos e entidades.
Legenda: nível de aceitação; energia; químicos, emissões de ar, saúde e segurança, sistemas de gestão, políticas ambientais, responsabilidade social, auditoria, implementação de programas e rótulos.
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Através do portal da MADE-BY é possível obter informação da marca, o scorecard da marca, isto é, onde é possível obter informação acerca dos locais de produção, o tipo de certificação social, a percentagem de utilização do algodão orgânico e classe dos materiais utilizados (A, B, C, D, E e outros). Pode-se ainda ter acesso à informação do circuito percorrido pelos produtos no planeta via password e ao website da marca.
Figura 5 Etiqueta MADE-IN e TRACK&TRACK
(Fonte: www.made-by.org)
O Caso da Marca Pure
A cadeia Bijenkorf foi fundada em 1870 em Amesterdão e possui 12 lojas na Holanda. Atualmente é parceira do rótulo MADE-BY. Em 2009 lançou a marca sustentável Pure: uma marca dirigida a uma mulher que gosta de saber o que está na moda. A nível das políticas sociais sustentáveis tornou-se membro da BSCI. Cerca de 30% da sua coleção é produzida segundo as condições aprovadas pela BSCI. Mais de metade da produção é realizada em Portugal, com classificação A (figura 6)5.
Figura 6 Scorecard da Marca Pure (Fonte: www.made-by.org)
5 www.made-by.org
A nível de impacto das matérias primas no meio ambiente a marca Pure utiliza nos seus produtos algodão orgânico e Tencel, ambas classe B, bem como na procura de soluções sustentáveis de produtos com os seus fornecedores da cadeia de fornecimento.
Figura 7 Scorecard da Marca Pure (Fonte: www.made-by.org)
O Caso do grupo PPR
O grupo PPR é um dos maiores grupos de moda de luxo e sportstyle. Com marcas como a Gucci, Balenciaga, Yves
rtney, Puma, entre outras.
A nível da política de sustentabilidade o grupo PPR lançou o programa Innovation and Sustainable Development Awards; introduziu critérios de sustentabilidade nas medidas de desempenho; desenvolveu parcerias para a melhoria das condições de trabalho nos seus parceiros na Europa. Em 2011 cria o seu departamento de sustentabilidade (PPR HOME), de forma a garantir as políticas de sustentabilidade em todo o grupo. Um dos objectivos principais do grupo é de garantir que grande parte dos lucros estejam relacionados com produtos e serviços sustentáveis e com criação de novos modelos de negócio.
Em 2011 as marcas do grupo criaram produtos sustentáveis e um conjunto de iniciativas concentradas em minimizar os impactos dos produtos na produção através da fase de criação do design adequado. O ciclo de vida dos produtos foi assim tido em conta e o uso de materiais mais sustentáveis, ou ainda, criando soluções inovadores na alteração dos produtos. Alguns exemplos das várias marcas são: (1) a edição limitada de mala Balenciaga, num conceito de reutilização da pele, reutilização da pele reciclada das coleções passadas para a atual; (2) a edição
Muse Two Artisanal Recycledsacos reciclados e benefícios sociais através da utilização das artesãs; (3) lançamento de uma linha de óculos pela Gucci com elevada percentagem de matérias primas
-
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Suede, utilizando 100% de matérias primas recicladas, reduzindo as emissões de CO2. A marca tornou-se ainda membro da organização sem fins lucrativos Textile Exchange e colocou 1,5 milhões de peças no mercado
lançou um programa que incentiva a devolução dos produtos em final de vida e criar uma segunda vida através da reciclagem6.
Conclusões
As estratégias e práticas associadas á sustentabilidade tiveram uma grande evolução nos últimos quatro anos. Um conjunto de entidades e rótulos sugiram no mercado permitindo ao consumidor obter informação acerca de um produto no ato da compra. As diretivas europeias e prazos estabelecidos para o seu cumprimento produzem resultados a nível do mínimo desempenho exigido ás empresas. Assim, os casos na cadeia têxtil aqui apresentados mostram um conjunto de boas práticas e iniciativas importantes para uma alteração do paradigma. É necessário ter essa consciência mas também é necessário criar condições no mercado para o aumento do consumo de produtos sustentáveis. As alterações no ciclo de vida dos produtos e a criação de boas práticas na concepção dos produtos pode alterar significativamente o futura da cadeia para um sector mais sustentável. No entanto, a diversidade de modelos de negócio com a deslocalização torna de algum modo o processo complexo e só com a colaboração de todos os parceiros será possível a a sua evolução no futuro. Portugal pode aqui encontrar uma vantagem competitiva criando um cluster de
maior número de empresas e rótulos no mercado.
Referências
1.European Commission, Policy options for the competitiveness of the European fashion industries,
Brussels 2012
2. ATP, XIV Fórum da Indústria Têxtil, 2012 3. Seymour, S. Fashionable Technology: The Intersection of Design, Fashion, Science, and technology, Springer, 2008 4. C.R. Carter, P.L. Easton; Sustainable supply chain management: evolution and future directions;International Journal of Physical Distribution and Logistics Management, 41 (1) (2011), pp. 46 62 5. T. Dyllick, K. Hockerts, Beyond the business case for corporate sustainability; Business Strategy and the Environment, 11 (2) (2002), pp. 130 141 6. S. Seuring, M. Müller; From a literature review to a conceptual framework for sustainable supply chain
6 http://www.ppr.com/en/sustainability/strategy
management Journal of Cleaner Production, 16 (15) (2008), pp. 1699 1710 7.S. Seuring, M. Müller; Core issues in sustainable supply chain management: a Delphi study; Business Strategy and the Environment, 17 (8) (2008), pp. 455 466 8. Stefan Seuring, A review of modeling approaches for sustainable supply chain management, Decision Support Systems, Available online 3 June 2012, ISSN 0167-9236, 10.1016/j.dss.2012.05.053
9.Comissão das Comunidades Europeias, sobre o Plano de Acção para um Consumo e Produção Sustentáveis e uma Política, Bruxelas, 2008 10.Comissão das Comunidades Europeia, Reponsabilidade social das empresas: uma nova estratégia da UE para o período de 2011-2014, 2011, Bruxelas
11. World Trade Organization, 2008 12. M. De Brito, V. Carbone, C. Blanquart; Towards a sustainable fashion retail supply chain in Europe: organisation and performance; International Journal of Production Economics, 114 (2) (2008), pp. 534 553 13. European Comission, Revision of European Ecolabel Critéria for textile products, Joint Reserach Centre, 2012, Brussels 14.Federico Caniato, Maria Caridi, Luca Crippa, Antonella Moretto, Environmental sustainability in fashion supply chains: An exploratory case based research, International Journal of Production Economics, Volume 135, Issue 2, February 2012, Pages 659-670, ISSN 0925-5273, 15. Zhaohui Wu, Mark Pagell, Balancing priorities: Decision-making in sustainable supply chain management, Journal of Operations Management, Volume 29, Issue 6, September 2011, Pages 577-590, ISSN 0272-6963, 10.1016/j.jom.2010.10.001. 16.Andrés Mazaira, E. González, Ruth Avendaño, "The role of market orientation on company performance through the development of sustainable competitive advantage: the Inditex-Zara case", Emerald 21 (2003)
Regulamentos:
Regulamento (CE) N.o 1221/2009 do parlamento europeu e do conselho de 25 de Novembro de 2009 relativo à participação voluntária de organizações num sistema comunitário de ecogestão e auditoria (EMAS), que revoga o Regulamento (CE) N.o 761/2001 e as Decisões 2001/681/CE e 2006/193/CE da Comissão.
Regulation (Ec) No 66/2010 of The European Parliament and of the Council of 25 November 2009 on the EU Ecolabel.
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Influence of ionic strength on the AO8 ionization
M.J.R.G. Pires1, M.I.A. Ferra1, A. Marques1 Chemistry Department, University of Beira Interior, 6201-001 Covilhã
Abstract Acid-base properties of acid orange 8 azo dye (AO8) were investigated and stoichiometric acidity constants were determined in sodium chloride solutions, at 25 ºC, from spectrophotometric measurements. The thermodynamic pKa value (pKa = 12.216) was found to be higher than the one for acid orange 7, showing that the methyl group in the AO8 molecule decreases its acid strength. For solutions with ionic strength higher than 0.25 mol∙ kg-1, a precipitate was observed indicating the
formation of aggregates, with alteration of the acid-base equilibrium. This fact was not observed for AO7 dye in solutions with ionic strength up to 2 mol∙ kg-1.
Introduction Azo dyes are of great importance in industry, namely, textile, paper, food, cosmetics and pharmaceutical industries. They are characterized by the presence of the N=N linkage [1] and they are constituting about 20-40 % of the total dyes used for coloring [2]. Acid orange 7 (AO7) and acid orange 8 (AO8) are azo dyes widely used in dyeing processes [3] and so they are also present in industrial effluents. They present identical molecular structures as shown in Figure 1.
Figure 1 - Molecular structure of AO7 (a) and AO8 (b)
The azo dyes present, in general, aromatic groups bound to the nitrogen atoms of the azo group. These are sulphonated azo dyes that have a hydroxyl group in the ortho- position with respect to the azo bond, which exhibits azo/hidrazone tautomerism [4,5]. This fact affects their colour properties.
Acid-base equilibrium of both compounds can be represented by the scheme shown in Figure 2, for AO8.
Figure 2 – Chemical species in an aqueous AO8 solution Acid-base properties of the acid orange 7 have been investigated in sodium chloride and sodium sulphate media as well as in water at 25 ºC. Its thermodynamic acidity constant, Ka, was found to be 4.246∙ 10-12 [6] in
close agreement with a previously published value (-logKa= 11.4) [3]. For AO8 a lower Ka value (Ka = 7.371∙ 10-13) has been determined [7] at the same
temperature. The aim of this work is a study on the ionization of AO8 in sodium chloride solutions. The behavior of both azo dyes is compared.
Materials and Methods From stock solutions of AO8 (C17H13N2O4SNa), purchased from Sigma-Aldrich, 65 %, dilute solutions with molalities around 4∙ 10-5 mol∙ kg-1 were prepared
in order to avoid the formation of aggregates [8] and to apply the Lambert-Beer law. Sodium hydroxide solutions, prepared from Titrisol ampoules, Merck, were used to increase the pH of the dye solutions. Sodium chloride from Merck, 99,5 %, was dried, at 110 ºC, over night and kept in a dessicator. All solutions were prepared with purified water, with a resistivity of 18 M� cm, obtained by a Milli-Q185 Plus, Millipore apparatus.
UV-visible spectra were run in a He�ios � spectrophotometer equipped with thermostatized quartz cells. The temperature was controlled by means of a
(a)
(b)
72
thermostat, Grant LTD 20, and a digital thermometer Hart Scientific 1502. Results and Discussion Spectra of aqueous AO8 solutions, at 25 ºC, are presented in Figure 3 at different pH values: 6.17, 11.30 and 12.88.
Figure 3 - Spectra of azo dye AO8 4.0∙ 10-5 mol kg-1 at
different pH values.
Absorbance measurements were taken at 490 nm, the analytical wavelength, where there is a big difference in absorbance between the two species, protonated and nonprotonated [9]. Dye ionization corresponds to the loss of a hydrogen ion from the anion, HA-: HA- H+ + A2- (1) and the thermodynamic ionization constant, Ka, is given by equation (2)
where m and � represent the molality and activity coefficient, respectively, of the indicated species and m0=1 mol∙ kg-1. The electric charges were omitted for
simplicity. The stoichiometric ionization constant, Km, is given by: Km=(mAmH)/(mHAm0). The value of mH was known from the solutions preparation and the ionic product of water [10,11] and the ratio mA/mHA was obtained from absorbance measurements of solutions of exactly the same dye molality at pH lower than 10.0 , higher than 12.0 and at intermediate pH values. In table I, pKm (pKm= -log Km) values for AO8, at 25 ºC, in aqueous solutions of sodium chloride are shown.
Table I – pKm values for AO8 in aqueous solutions of sodium chloride, experimental (Exp.) and calculated (Calc.) by equation (5).
I / (mol∙kg-1) pKm
Exp. Calc.
0.002 12.142 12.134 0.012 12.044 12.042 0.042 11.952 11.953 0.102 11.887 11.902 0.162 11.897 11.897 0.202 11.899 11.904 0.252 11.929 11.919
Equation (3) was used to evaluate the ionic activity coefficients [12], γi, in the solutions where the ionic strength was increased by adding NaCl.
In this expression, bi is an empirical parameter. Both a and bi are adjustable to suit the experimental data. From equations (2) and (3), equation (4) is obtained
where pKa=-log Ka. Equation (4) can be rewritten as:
where P0 = pKa , P1 = and Y is given by equation (6)
By regression analysis, the parameters P0 and P1 were obtained for AO8: P0 = 12.216±0.005; P1/(mol-1∙ kg) = 0.906±0.037 . The best fit was obtained with Ba =1.9 mol-1/2∙kg1/2. Values of pKm could then be calculated and are also given in Table I for the same solutions. The variation of pKm with I1/2, for AO8, is illustrated in Figure 4-(I), according to the equation (4) (full lines). In the same figure (II), the variation of pKm with I1/2 for AO7 [6] is also shown for comparison. For this dye, the pKm determinations were performed at much higher ionic strength than for AO8. Experimentally it was not possible to obtain consistent pKm values for AO8 at ionic strength higher than 0.25 mol∙ kg-1, probably due
0,0
0,2
0,4
0,6
0,8
1,0
280 330 380 430 480 530 580
Abs
orba
nce
Wavelength / nm
— pH 6.17
… pH 11.30 --- pH 12.88
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to the formation of aggregates. The points indicate experimental data.
Figure 4 - Variation of pKm with I1/2, at 25 ºC, according to equation (4) (full lines) and experimental values: (I) - in AO8 solutions; (II) - in AO7 solutions [6]. Conclusions The value of pKa for AO8, determined at 25 ºC, is 12.216, obtained from extrapolation to zero ionic strength, applying the equation (3) to the evaluation of the ionic activity coefficients in sodium chloride solutions. This value is higher than that obtained for AO7 (pKa=11.372 [6]) showing the influence of the methyl group in increasing pKa values, as discussed by Oakes et al. [14]. For ionic strength higher than 0.25 mol∙ kg-1 the formation of a precipitate was visible, with alteration of the chemical equilibrium between the protonated and nonprotonated species. This fact was also observed for the AO7 dye, but only for ionic strength higher than 2 mol∙ kg-1.
References 1. Saquib, M., Munner, M., Desalination, 155, 255,
2003. 2. W, J., Eitman, M.A., Law, S.E., J. Environ.
Eng.,12(3), 272, 1998. 3. Zollinger, H., Color Chemistry – Synthesis,
Properties and Applications of Organic Pigments,
Third revised edition, Wiley- VCH, Weinheim, 2003.
4. Hihara, T., Okada, Y., Morita, Z., Dyes and Pigments, 59, 201, 2003.
5. Hihara, T., Okada, Y., Morita, Z., Dyes and Pigments, 59, 25, 2003.
6. Pires, M.J.R.G., Ferra, M.I.A., Marques, A., Ionization of AO7 in different ionic media, Actas do Simpósio 2011: Transferência de Conhecimento e Tecnologia, UMTP, Universidade da Beira Interior, 67, Dez. 2011.
7. Pinto, V. M. B., Pires, M.J.R.G., Ferra, M.I.A., Marques, A., Ionization of Acid Orange 8, Actas do Simpósio 2011: Transferência de Conhecimento e Tecnologia, UMTP, Universidade da Beira Interior, 67, Dez. 2011.
8. Alarfaj, N.A., Khiate, Z.M., Moussa, E.A., JKAU:Sci., 20, 99, 2008.
9. Albert, A., Serjeant, E.P., The Determination of Ionization Constants – A Laboratory Manual, Third Edition, Chapman and Hall, New York, 1984.
10. Harned, H.S., Owen, B.B., The Physical Chemistry of Electrolytic Solutions, 3ª ed., New York, Reinhold Publishing Corporation, 1969.
11. Covington, A.K., Ferra, M.I.A., Robinson, R.A., J. Chem. Soc. Farad. Trans., 73, 1721, 1977.
12. Robinson, R.A., Stokes, R.H., Electrolyte Solutions, 2ª ed. Revised, London, Butterworth and Co., 1970.
13. Bates, R.G., Guggenheim, E.A., Pure Appl. Chem., 1, 163, 1960.
14. Oakes, J., Gratton, P., J. Chem. Soc., Perkin Trans 2, 1857, 1998.
Acknowledgements The authors are grateful for the financial support from the Research Unit of Textile and Paper Materials, Fundação para a Ciência e Tecnologia (FCT), Portugal.
11,80
11,90
12,00
12,10
12,20
12,30
0,00 0,10 0,20 0,30 0,40 0,50 0,60
pKm
I1/2 / (mol∙kg-1)1/2
10,90
11,00
11,10
11,20
11,30
11,40
11,50
0,00 0,25 0,50 0,75 1,00 1,25 1,50
pKm
I1/2 / (mol∙kg-1)1/2
(II)
(I)
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Fabricação de materiais têxteis compósitos sustentáveis com matriz de Hevea Brasiliensis e reforço em malhas.
E. Garcia 1, M.J.O.Geraldes2 Universidade da Beira Interior.
Abstract Tecidos compósitos de borracha natural da árvore Hevea Brasiliensis, são produzidos por índios e seringueiros na floresta amazônica, e comercializados com o nome de Couro Vegetal e Tecido da Floresta desde 1992. Entretanto devido sua base têxtil de tafetá de algodão, o material não apresenta muita elasticidade, bem como pouca variedade de característica de estrutura. Este artigo apresenta o resultado do procedimento de fabricação de um novo material têxtil sustentável em processo artesanal, realizado no Brasil, na floresta Amazônica, por índios e seringueiros através da alteração na base por malhas de diferentes estruturas e fibras, com revestimento de matriz polimérica de látex natural da resina da árvore Hevea Brasiliensis.
O processo foi executado na Reserva Florestal de Aquariquara no Vale do Anarí, em Rondônia, e contou com a participação de índios e seringueiros da COOPFLRA - Cooperativa Florestal dos Seringueiros de Rondônia. O látex utilizado como resina de revestimento é de espécie nativa, e o procedimento de laminação utilizado foram manuais. Enquanto o processo de vulcanização foi por uso de enxofre, a reticulação dos mesmos se deu através do método de defumação e por energia solar.
Como resultado obteve-se diferentes materiais têxteis, com aparência diferenciada, entretanto com aspectos estéticos similares ao couro e compósitos sintéticos, com variações na espessura, leveza, maior elasticidade e aparência diferenciada na superfície. Cuja aplicação pode ser diversa, incluindo calçados, acessórios, capas malas, têxteis lar, vestuário entre outras Foi também fabricado um calçado feminino como protótipo, possibilitando figurar o uso comercial do mesmo.
A contribuição deste trabalho para a engenharia têxtil se deu pelo resultado da evolução deste material sustentável com possibilidade de novas aplicações e abordagens, como observado através no protótipo construído, um calçado feminino com boa aderência estética de superfície, e na interface do compósito com a cola e o solado, assim como a costura e o recouro.
Introduction Relata-se que os índios sul americanos confeccionavam vários artigos encauchados, que significa “cahuctchu”, que quer dizer “madeira que chora”. A borracha era fabricada através da secagem do látex à temperatura
ambiente, uma prática não prejudicial ao ecossistema. (Salomek, 2006).
Este processo sofreu pequenas alterações no decorrer dos anos e seu uso comercial só se deu 20 anos atrás, sobre patente de “couro vegetal”. A resina foi substituída pela resina da árvore Hévea Brasiliensis, devido sua melhor qualidade em borracha.
A Hevea Brasiliensis desempenha um importante papel na conservação da floresta Amazônica, por tratar-se da espécie que mais absorve CO² do planeta terra, e desempenhar importante fonte e renda as pequenas comunidades de índios e seringueiros, conhecidos como “os guardiões da floresta”, porque são estes que impedem o fazendeiro e o pecuarista da destruição da mata.
Um material compósito é uma mistura de dois materiais com características físicas diferentes, com objetivo de para formar um novo material diferente dos materiais puros. Estes podem ser micro ou macro constituintes que, diferem na forma e na composição química e que, em sua essência, são insolúveis uns nos outros. (Smith 1996; Chawla, 1987).
Outra característica do compósito é o fato de não ser homogêneos, e ser formados por duas ou mais fases, separadas por uma interface, física e quimicamente diferentes. Uma das fases sempre será contínua, que é a matriz, e a outra fase, dispersa, podem ser constituídas por partículas, fibras ou filamentos (William, 1998; Araújo et. al.2001a).
Assim o resultado de um bom compósito dependerá tanto da matriz escolhida quanto do polímero utilizado, assim como o processo de vulcanização, considerando que cada alteração exercerá fundamentalmente influência nas características tanto físico-mecânicas, como estéticas do material.
Dentre os chamados materiais do novo milêneo em crescimento da procura de materiais ecologicamente corretos e biomateriais caminham em ritmo cada vez maior, cuja aplicação estende-se de tecidos técnicos, à moda ou medicina. Entre estes a borracha da Hevea brasiliensis é um elastomero complexo, sendo sua capacidade de voltar a forma original após estiramento uma ótima característica tratando de um produto têxtil. Em sua composição além do elemento base hidrocarbonetos isoprênicos (C H8) contém proteínas, sais minerais, lipídeos, fosfolipídeos, carboidratos, metais,
75
açúcares, o que amplia o seu campo de atuação. (Herculano, 2005; Cid et.al, 1995:4 e Servolo, 2006:11)
Entretanto por se tratar de um composto perecível, o mesmo necessita de vulcanização a fim de garantir características mecânicas como resistência a tração, abrasão entre outras (Smith, 1996:329).
A introdução comercial dos compósitos sintéticos desenvolveu-se no século XX com grande impulso a partir de 1971, entretanto o uso do látex de hevea brasiliensis vem se desenvolvendo de 100 anos para cá atrás da fabricação artesanal do saco encauchado pelos índios e seringueiros. Depois de estudos químicos passa a receber agentes vulcanizantes para garantir resistência a tração do mesmo, que acaba sendo patenteado com a marca “Couro Vegetal”.
O mesmo apresenta algumas características de plasticidade o que limita o uso do material a bolsas e malas e tempo de vida relativamente curto. Alguns anos aos depois outro grupo de estudos no Amazonas consegue eliminar a plasticidade e aumentar a durabilidade do material através da inclusão de agentes químicos aceleradores e retardadores e diminuir o forte cheiro da borracha, que passa a ser patenteado pela COOPFLORA como Tecido da Floresta.
Na evolução dos compósitos particulados, os novos encauchados da Amazônia tiveram início a partir de 2002 através do POLOPROBIO nas Universidades Federais do Amazonas, tendo o grande diferencial na substituição do estabilizador químico de pH por uma mistura de “água de cinza”, caseira, feito das sobras dos fornos ou fogões a lenha. É um grande salto tecnológico porque dispensa a vulcanização por defumação e dispensa o enxofre.
A industrialização do processo passa então a ser realizada em 2004, através de método contínuo no interior de São Paulo, entretanto ainda carecem melhorias como a contínua redução do cheiro, no material artesanal, oxidação do material, causando manchas brancas, principalmente no produto industrial e a elevada rigidez e pouca elasticidade do produto, que dificulta na fabricação de calçados e peças do vestuário.
É neste último aspecto que se caracteriza o objetivo principal deste trabalho, ou seja, fabricar um têxtil alternativo ao ecodesign, de matriz polimérica de látex de borracha natural, em uma base têxtil com fibras contínuas em variadas estruturas de malha. Onde a aplicação de uma base mais elástica propiciará maior facilidade na modelagem do produto final. Esta será realizada através da coleta e aplicação da resina em árvores nativas na floresta Amazônica por índios e seringueiros e através do processo Industrial com resina de árvores e plantio, através da vulcanização com em método contínuo e estufa para aplicações diversas.
Materials and Methods As malhas foram selecionadas na empresa LMA Têxteis em Portugal, dentre distintas fibras e estruturas, entre elas, Jersey, Rib e Interlock , preferencialmente unidirecionais ou com baixa elasticidade. Na qual 70 amostras são submetidas a ensaio de viscosidade, onde é aplicada uma solução de baixa viscosidade contendo látex e amônia estabilizado em pH 10, e com auxílio de um conta gotas.despeja-se 5 gostas e verifica-se visualmente o processo de migração que não poderia ser inferior a 10 segundos Assim, selecionaram-se 13 malhas, nos quais o látex se espalhou mais lentamente pelo substrato têxtil. Table 1 –Característica das malha ensaiadas. Fonte: Autor
Código Tecido Composição
Massa/unidade superfície
(+ ou- 5)Comp
Estrutura
8186 8309 8162
100%WO 0,220 Knit-interlock 100% PES 0,85 Knit-interlock 100%PA** 0,245 Knit-interlock
8009 8044 8157
100%PES 0,288 Knit-interlock 100%PES 0,170 Knit-interlock 100%PES 0,155 Knit-interlock
7235 * 7181 7240 7122
100% PES 0,200 Knit Jersey 100%PES 0,220 Knit Jersey 92%CV2%EA 0,155 Knit Jersey 68% PES 34% PP 0,185 Knit Jersey
5090 3522* 5101
100%PES 0,195 Warp Knit 100%PES 0,87 Warp Knit 100%PES 0,80 Warp Knit
*Dry Finishing- Acabamento químico que confere à fibra elevada capacidade de absorver aumidade e transportá-la para o exterior. Permite uma secagem rápida mantendo o corpo confortável.
Processo Industrial
O processo de vulcanização industrial foi realizado na empresa Ecológica Laminados S.A., em São Paulo, onde as malhas foram unidas por costura e a tecnologia aplicada através de esteira contínua, e estufa. O produto químico base da vulcanização utilizada é o enxofre, entretanto os demais agentes estabilizantes não foram revelados a fim de garantir segredos industriais.
Após ensaios de viscosidades na LMA têxtil, foram selecionados 12 tecidos, que no laboratório da empresa Ecológica Laminados S.A. passaram por outros testes de compatibilidade. Contudo, por se tratar de um liquido de baixa viscosidade, quase heterogêneo, em que a água é a fase contínua, ocorreu incompatibilidade entre a malha e polímero (látex), que quando aplicado na malha e após a evaporação dos 40%, de água, forma um solido filme de camada polimérica pastosa, sem que haja uniformidade na peça.
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Processo Artesanal
O processo artesanal de polimerização e vulcanização desenvolveu-se no Amazonas, na reserva florestal de Aquariquara, vale do Anarí. Cuja coleta se dá em uma área de latitude 09º26'38" sul e a uma longitude 61º58'53" oeste, sendo este um dos pontos de maior concentração de umidade da floresta com médias entre 90% a 100% o que caracteriza como látex de boa qualidade. Esta foi realizada no mês de Abril, período final das chuvas tropicais, ainda com pluviosidade em torno de 1.900mm a 2.500mm, e temperatura entre 26°C pela manhã e 34°C no período da tarde.
O trabalho começa as 5 da manhã, quando as árvores são localizadas na floresta, considerando a distribuição entre 1 a 3 árvores por hectare e cortadas para a extração da seiva, a seguir, a resina é depositado em um balde plástico de 20 litros, recebendo amônia para estabilizar o pH entre 7 à 10 e evitar a oxidação. Em seguida são acrescidos uma mistura contendo os agentes vulcanizantes e corantes, sendo estes um produto comercial da empresa Enro Industrial Ltda, chamado VULCAT EX C 2218, que contém aceleradores e ativadores e neste caso usado em proporções de 20g do produto por Kg de látex:
� Óxido de zinco (ZnO); � Enxofre (S8); � dissulfeto de tetrametiltiuram (TMTD) � 2,2-di tiomercaptobenzotiazol -sul fenamida
(MBTS); � Noxidietilenobenzotiazol � -2-sulfenamida (MBS); � Ciclohexilbenzotiazol -sulfenamida (CBS); � 4,4'-ditiodimorfolina (DTDM); � N-oxidietilenotiocarbamila-N-oxidietilenosul
fenamida (OTOS).
Figura 1- aplicação da resina sobre a tela têxtil
São construídas telas de madeiras de reaproveitamento cuja malha foi estica manualmente e cuidadosamente, de forma a não distorcer a direção da trama e da teia, visando preservar o design da superfície sem causar defeito. Na primeira aplicação o método escolhido foi a vulcanização por defumação, com aplicação da resina e técnica manual impregnando o produto no avesso da malha (figura 1),
sequentemente, a tela é levada até a boca do buião1, onde fica em contato com a fumaça por cinco minutos. Neste caso, não ocorreu aderência dos polímeros a malha, tendo-se formado pequenos coágulos que conforme secavam iam se desprendendo do têxtil.
A solução encontrada foi lavar o tecido, a fim de retirar prováveis materiais depositados no acabamento da malha que impediam à impregnação do mesmo. Assim, a malha foi reposta ainda molhada, o que possibilitou um bom resultado. Sucessivamente intercalando mais 4 demãos de resina com 5 minutos na fumaça. A seguir, rapidamente o compósito é lavado em água corrente e posto ao sol para pós-cura por 30 minutos.
Foram submetidas ao processo de vulcanização por defumação as malhas: 3522, 7240, 7235, 8157, descartando a malha 8309, sendo as vulcanizadas por energia solar em temperatura superior a 35 graus e umidade superior a 75% e, seguindo o seguinte processo:
� Esticar o tecido na tela; � Lavar a malha com água para retirar resíduos; � Preparar a resina; � Impregnar a tela com a resina na frente e verso
da malha; � Secar ao sol durante 20 minutos; � Aplicar segunda demão de resina (apenas no
direito do tecido); � Levar ao sol por mais 15 minutos e,
sucessivamente, repetir a aplicação intercalada com o sol mais quatro vezes;
� Deixar ao sol para secar durante mais de três horas.
� Lavar em água corrente e passar silicone à base de água. Se desejar eliminar o odor, usar desodorizante à base de óleos vegetais.
Results and Discussion
Todas as malhas vulcanização através do processo industrial não apresentaram o resultado esperado, sendo registrados diferentes problemas, como a formação de bolhas de ar na camada de polímero, a migração parcial ou total da resina na parte inferior do tecido que ocasionou não uniformidade da camada de revestimento.
Ainda não se podem determinar as causas que determinaram estas falhas, mas o uso da limpeza do
1 Buião é o nome denominado a um forno de barro abastecido com coco da planta babaçu e lenha da árvore Breu.
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substrato têxtil com desencolagem, ou seja, submeter o tecido a fervura com alguns agentes químicos para eliminar a goma e impureza do fio e do tecido.
Pinheiro (2012) acredita que vário destes problemas tem origens diversas e passíveis de corrigir como a formação de bolhas que pode ser uma falta da habilidade do uma desengomagem, que consiste na imersão do tecido em resorcinol formaldeiro (RFL), a fim de eliminar impurezas e respondendo melhor a resina.
Alterações na composição química, como o elevado teor de pH, o excesso de plastificantes ou aceleradores como o TMTD, poderiam causar a migração para a resina na parte inferior da malha.
Um estudo da reometria de torque e HANKE poderá determinar o tempo para cada tecido em estufa evitando a plasticidade e aumentando a elasticidade.
No compósito revestido artesanalmente, tanto o processo de vulcanização em defumação, como a vulcanização através de energia solar resultaram em materiais compósitos diferenciados, com algumas características visuais semelhantes ao couro e outros materiais sintéticos destinados.
Conseguiu-se uma variedade de 13 matérias diferenciados em textura de superfície, elasticidade e leveza. Onde foi confirmada a sua usabilidade através da construção de um protótipo, sendo este um calçado feminino, da qual apresentou boa aderência à cola, ao recouro, solado e costura e aparência estética.
Verificou-se que tanto no processo industrial quanto no artesanal, embora apresentassem consideráveis diferenças na massa por unidade de superfície, na estrutura da malha, ou mesmo a fibra de base não foi responsáveis diretos pelo resultado positivo ou negativo, uma vez que todos foram rejeitados no industrial em contraste com todas as aprovadas no processo artesanal.
Certificou-se que no processo de aplicação da resina, não se polui com resíduos e a preocupação em diminuir ainda mais a poluição, vem levando seringueiros a propagar a vulcanização no sol, preservando também a saúde do seringueiro, sugerindo assim a substituição por esteiras elétricas. O compósito apresentou um forte cheiro de borracha, o que sugere aperfeiçoamento em futuras pesquisas no intuito da inclusão de desodorizantes na composição do produto. Observou-se que o uso de corantes naturais vem sendo substituído pela facilidade dos corantes químicos, visando satisfazer gostos e tendências do setor têxtil. Entretanto, ocorreram problemas no substrato têxtil causados pela má dissolução dos mesmos gerando manchas na textura que prejudicam a qualidade da peça, bem como outras pequenas imperfeições oriundas de poeiras que aderem à estrutura têxtil, durante a polimerização por energia solar.
Referencias Araújo, M. Fangueiro, Raul; Hong, H. (2001a).Têxteis técnicos Materiais do novo milénio- Visão geral. Vol.I. Braga. 110 p. Cid, C.C.A. Regina; Costa,R.M. Djanira; Filho, S.S. Antonio; Nakamura,M.KLysia. (1995). Desenvolvimento do couro vegetal a partir do látex "in natura". InstitutoNacionalde Chawla, K.K. " Composite Materials : Science and Engineering ", Springer - Verlag New York Inc., 1987. Pinheiro, S. Mario. (2012) Manual de Formulações de Artefatos de Borracha. Editora Evangraf. Porto Alegre. ISBN 978-85-7727-391-1 Herculano, D R.(2009)“Desenvolvimento das Membrana de látex natural para aplicações médicas”.Tese de Doutorado em Física aplicada à Medicina e Biologia, apresentada à faculdade de Filosofia Ciências e Letras de Ribeirão Preto/UPS. Ribeirão Preto, 152p.:il.; 30cm Samonek, F. (2006). A borracha vegetal extrativia na Amazônia: um estudo de caso dos novos encauchados de vegetais no Estado do Acre. Tese de mestrado em Ecologia e Manejo de Recursos Naturais - Departamento de Ciências da Natureza, Universidade Federal do Acre, Rio Branco-Acre.CDU 581.5 (811.2) 160p.
Servolo, F. H. J. (2006). Avaliação à tração de couro vegetal de tecidos de algodão impregnado com látex de cinco cultivares de seringueira (Hevea spp.) e vulcanização Tese de mestrado apresentada ao curso de Engenharia Agrônoma Escola Superior Agrícula Luiz Queiroz. Piracicaba, 53p. Smith, W. F. (1996). Princípios de Ciência e engenharia dos Materiais.5ª edição. Editora Castilho Filho, Lisboa. ISBN: 972-8298-68-4. William, D.C. Jr.(1998) Introducción a la Ciência e ingeniéria de los Materiales. Editora Reverté S:A. Barcelona p. 803. 2 vol.ISBN 84 291 7252 1 Agradecimentos LMA Têxtil- Portugal
COOPFLORA- Cooperativa da Floresta Extrativista de Rondônia
Ecológica Laminados S.A.
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Ferrocene Derivatives with Potential Biological Activity
S. Santosa, J.A. Figueiredoa, M.I. Ismaela, A.C. Fernandesb
a Departamento de Química, Unidade de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, Covilhã, Portugal b Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Lisboa, Portugal
Abstract The aim of this work is the synthesis of several ferrocene derivatives with biological properties. Two types of compounds were synthesized: one are ferrocene hydrazones derivatives and the other are ferrocene triazolesugars derivatives. Ferrocene hydrazones were obtained from reaction between ferrocenyl carbonyl compounds with hydrazine derivatives. Ferrocene triazolesugars were formed by click chemistry techniques, which is a method that consists of the regiospecific catalytic cycloaddition of propargyl ferrocene and azidosugar leading to the formation of 1,2,3-triazole ring between ferrocene and sugar moiety. Antioxidant activity of some final compounds was determined. Introduction Hydrazones and their derivatives constitute a versatile class of compounds in organic chemistry, and they have interesting biological properties, such as anti-inflammatory, analgesic, antitumor, and antimicrobial activity. Hydrazones are also an important class of compounds for new drug development [1]. The synthetic efforts for this class of compounds are very well studied and generally entail the reaction of carbonyl compounds with hydrazine in organic solvents [2]. During the last decades the chemistry of ferrocenes has attracted remarkable attention due to their wide range of interest in material sciences, catalysis and biological assays [3]. Ferrocene has attracted special attention since it is neutral, chemically stable and nontoxic molecule. Many ferrocenyl compounds display interesting cytotoxic, antitumor, antifungal, antioxidant and DNA-cleaving activity [4]. The incorporation of ferrocene in biomolecules conveys unique properties such as aromaticity, stability in aqueous and aerobic media, low toxicity, lipophilicity and easy access to one-electron oxidation potentials [5]. Among various naturally occurring compounds, carbohydrates are readily available, cheap, biodegradable and nontoxic materials [6]. According to the literature a wide variety of heterocyclic scaffolds possess valuable pharmaceutical properties including anticancer effects [3]. Structural motifs containing ferrocene-triazoles and carbohydrate-triazoles are well known for their cytotoxicity and antimicrobial
activities. Apart from these activities, the antioxidant behavior of the conjugates is also enhanced due to the reversible redox property of ferrocene. Therefore, medicinal application of ferrocene is an active research area and many reports have shown that ferrocene-carbohydrates derivatives have a highly promising activity in vitro and in vivo against several diseases [5]. We report the simple synthesis of several ferrocene hydrazones and the cycloaddition reaction between a terminal alkyne ferrocene and azidosugar. The last reaction is known as click chemistry reaction and leads only to the 1,2,3-triazole ring between a ferrocenyl residue and a sugar moiety. These reactions involve the use of easily available starting materials, both commercially and synthetically [6]. Results and Discussion
Synthesis and determination of antioxidant activity of ferrocene hydrazones
Ferrocenyl hydrazones 3a-d were synthesized according to the reported procedure (scheme 1). The hydrazines 2a-d reacted with equimolar amounts of commercially ferrocene carboxaldehyde 1 in ethanol. Reaction occurred at room temperature for 1-5 h under inert atmosphere. The solvent was evaporated and the residues were purified by silica gel column chromatography to give ferrocenyl hydrazones 3a-d in 80%, 91%, 34%, and 77% yields, respectively.
CH
O
+ R
CH
N
HN
R
H3CO
OO
1
a bO2N NO2
c d
EtOH
5h, room temp., Ar
2a-d 3a-d
SCHEME 1
Antioxidant activity of the compounds 3a-d and the standard trolox was determined using the radical
79
scavenging activity method with 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·). After a 90 min incubation period at room temperature in the dark, the absorbance was measured at 517 nm, and was used DPPH concentration of 50 mg/L and samples concentrations of 750 to 25 mg/L. The tests were carried out in triplicate and the radical scavenging activity was determined by a calibration curve of percentage of inhibition (I %) versus compounds at differents concentrations (Figure 1).
Figure 1 – Inhibition (%) of 3a-d and trolox (standard). The most promising antioxidant compound is 2,4-dinitrophenylhydrazone derivative 3d, exhibiting maximum inhibition of 60.20%. The compound 3b presented less percentage of inhibition. These results evidenced the importance of structure in the antioxidant activity of compounds. The compounds which have phenyl groups in its chemical structure have more antioxidant activity. Nitro groups also presented great importance to increase antioxidant activity.
Synthesis of Ferrocene-triazolesugars The synthesis of Ferrocene-triazolesugars 6e-i was made by the click chemistry reaction of ferrocene derivative with a triple bond and different azidosugars (scheme 2).
Fe
O
4 5e-i
CuSO4.5H2Osodium ascorbate
tBuOH/H2O, 40ºC
Fe
O
N N
NSugar
Sugar: O
OO
OO
OOH
OO
OHO
OH
OO
O
OCH3OH
OHOH
O
OAc
OAcOAc
OAc
Sugar N3
6e-i
e f g h i
SCHEME 2 Prop-2-ynyloxymethylferrocene 4 and pyranosidic or furanosic azidosugars 5e-i were suspensed in a 1:1 mixture of water and t-butyl alcohol. Sodium ascorbate and CuSO4.5H2O were added to this solution, and the heterogeneous mixture was stirred vigorously at 40ºC for
6h. The solvent was removed by evaporation under vacuum and the crude was purified by silica gel column chromatography to give compounds 6e-i in 83%, 78%, 79%, 75%, and 63% yields, respectively. Structural analysis of the synthesized compounds was made by spectroscopic techniques, namely infrared (IR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. Conclusions In conclusion, were described two methods for the synthesis of several ferrocene derivatives with potential biological activity and the determination of antioxidant activity of the ferrocene hydrazones. The formation of ferrocene hydrazones 3a-d by reaction of hydrazine derivatives with ferrocene carbonyl derivatives were performed using conventional method, involving small volume of solvent and short reaction time. The studied compounds presented a percentage of inhibition in the range of 4.55%-60.20% at 750 mg/L. The antioxidant activity observed for all of compounds is smaller than that of trolox. However, ferrocene carboxaldehyde linked to 2,4-dinitrophenylhydrazine 3d exhibit higher antioxidant activity than other compounds, due to the nitro groups present in its structure. Finally, the synthesis of ferrocene-triazolesugars 6e-i made by click chemistry reaction demonstrated that this is a good method for the synthesis of this type of compounds. These compounds will be tested to determine its biological activity. References 1. Rollas, S.; Küçükgüzel, Ş .G.; Molecules, 2007, 12, 1910-1939. 2. Cui, Z.; Yang, X.; Shi, Y.; Uzawa, H.; Cui, J.; Dohi, H.; Nishida, Y.; Bioorganic & Medicinal Chem. Letters, 2011, 21, 7193–7196. 3. Á. Gyömöre, A. Csámpai; J. of Organometallic Chem., 2011, 696, 533-539. 4. G. M. Maguene, J. Jakhlal, M. Ladyman, A. Vallin, D. A. Ralambomanana, T. Bousquet, J. Maugein, J. Lebibi, L. Pélinski; Eur. J. of Medicinal Chem., 2011, 46, 31-38. 5. R. Trivedi, S. B. Deepthi, L. Giribabu, B. Sridhar, P. Sujitha, C. G. Kumar, K. V. S. Ramakrishna; Eur. J. Inorg. Chem., 2012, 2267-2277. 6. J. M. Casas-Solvas, A. Vargas-Berenguel, L.F. Capitán-Vallvey, F. Santoyo-González; Organic Letters, 2004, 6, 3687-3690. Acknowledgments The authors acknowledge to FCT for financial support through project PTDC/QUI-QUI/110532/2009.
0
20
40
60
80
100
0 150 300 450 600 750
Inhi
bitio
n (%
)
Concentration (mg/L)
3a 3b 3c 3d Trolox
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Synthesis and characterization of iminosugars
M. Domingues1, M.I. Ismael1, J.A. Figueiredo1, M. Schuler2, A. Tatibouët2.
1 UMTP and Department of Chemistry, University of Beira Interior, Covilhã, Portugal 2 ICOA – Institut de Chimie Organique et Analytique, University of Orléans, France
Abstract The aim of this work was a novel and efficient strategy for the synthesis of iminosugars with potential biological activities. In this work the starting material was D-ribose. The early introduction of an azide function at C-5 of 2 shortened the synthetic pathway to obtain iminosugars. Pure compounds obtained were characterized and identified by spectroscopy using infrared (IR) spectroscopy and nuclear magnetic resonance spectroscopy of proton (1H-NMR) and carbon (13C-NMR). Introduction Iminosugars our azasugars are mimetics of native sugars. Due to their structural similarity to native carbohydrates, iminosugars are able to act as glycosidase inhibitors and therefore have enormous therapeutic potential in the treatment of a variety of diseases including viral infection, that is, human immunodeficiency virus (HIV), human hepatitis B virus (HBV), human hepatitis C (HCV), bovine viral diarrhea virus (BVDV), Japonese encephalitis virus (JEV), and dengue virus, as well as cancer, diabetes, tuberculosis, malaria and lysosomal storage diseases1-4. Indeed, the use of Zavesca for the treatment of Gaucher’s disease marked the launch of the first iminosugar medication5. In view of the growing biological importance of iminosugars, our interest has been in the development of new methodologies for the synthesis of this class of compounds. Materials and Methods Thin layer chromatography was used to check the progress of reactions and during purification. TLC plates proved/powered by UV light and immerse in a reveling and then heated to 100ºC. The synthesized compounds were purified by column chromatography, using silica gel SI 60 (40-63μm) and chromatographic columns were eluted by gravity with the help of pump. Structural characterization was undertaken by infrared (IR) spectroscopy, nuclear magnetic resonance spectroscopy of proton (1H-NMR) and carbon (13C-NMR) performed on BRUKER AC 400 spectrometer, operating at 400 MHz for proton and 100 MHz for carbon. Chemical shifts are reported in units of δ (ppm) and were obtained for each compound, at room temperature and in
solution of deuterated solvents. Coupling constants (J) are expressed in Hz. Results and Discussion In the first steep D-ribose was converted in to azidosugar 3 (Scheme 1) with an overall yield of 90% . Starting with D-ribose, at the same time we protect the anomeric hydroxyl group with the methyl group and the hydroxyl group 2 and 3 with the isopropylidene group to obtain 1-O-meethyl-2,3-isipropilydene-β-D-ribofuranose (1). Compound 1 originate a 5-iodine-deoxy-sugar (2) by ionic deoxygenation of hydroxyl group at C-5. The introductions of azide function at C-5 of methyl-5-deoxy-5-iodine-2,3-O-isopropylidene-β-ribofuranose (2) give the azidosugar 3.
2 3
a)
c)
b)
1
Scheme 1- Synthesis of (3aR,4R,6R,6aR)-6-(azidomethyl)-4-methoxy-2,2-dimethyl-3a,4,6,6a-tetrahydrofuro[3,4-d][1,3]dioxole (3) from D-ribose. (a) MeOH, acetone, H2SO4, r.t., 48h, 85% ; (b) Ph3P, imidazol, I2, Tolueno, 80ºC, reflux, 5h, 88%; (c) NaN3, DMSO, 100ºC, reflux, 3h, 98% . Removal of the isopropylidene group of (3aR,4R,6R,6aR)-6-(azidomethyl)-4-methoxy-2,2-dimethyl-3a,4,6,6a-tetrahydrofuro[3,4-d][1,3]dioxole (3) give the azidosugar 4. Removal of the isopropylidene group and methyl group of (3aR,4R,6R,6aR)-6-(azidomethyl)-4-methoxy-2,2-dimethyl-3a,4,6,6a-tetrahydrofuro[3,4-d][1,3]dioxole (3) give de azidosugar 5 (Scheme 2).
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and
4 53
a)
Scheme 2- Synthesis of azidosugar 6 and 7 from (3aR,4R,6R,6aR)-6-(azidomethyl)-4-methoxy-2,2-dimethyl-3a,4,6,6a-tetrahydrofuro[3,4-d][1,3]dioxole(3). (a) H2SO4 4M, HCl 3M, r.t., 12h, 30% for compound 4 and 70% for compound 5. In situ reduction of (2R,3S,4R,5R)-2-(azidomethyl)-5-methoxy-tetrahydrofuran-3,4-diol(4) followed by N-cyclization led to the iminosugar 6 (Scheme 3).
a)
64
Scheme 3- Synthesis of (2S,3R,4R,5R)-2-methoxypiperidine-3,4,5-triol (6) from azidosugar 4. (a) Pd/C, H2CONH4, ethyl acetate, 70ºC, reflux, 18h, 80%. In situ reduction of (3R,4S,5R)-5-(azidomethyl)tetrahydrofuran-2,3,4-triol( 5) followed by N-cyclization led to the iminosugar 7 (Scheme 4).
a)
75
Scheme 4- Synthesis of (3R,4R,5R)-piperidine-2,3,4,5-tetrol (7) from compound 5. (a) Pd/C, H2CONH4, ethyl acetate, 70ºC, reflux, 18h, 22%. In situ reduction of (3aR,4R,6R,6aR)-6-(azidomethyl)-4-methoxy-2,2-dimethyl-3a,4,6,6a-tetrahydrofuro[3,4-d][1,3]dioxole (3) followed by N-cyclization led to the iminosugar 8 (Scheme 5).
3
a)
8
Scheme 5- Synthesis of (3aR,4S,7R,7aR)-4-methoxy-2,2-dimethyl-3a,4,5,6,7,7a-hexahydro-[1,3]dioxolo[4,5-
c]pyridin-7-ol (8) from azidosugar 5. (a) Pd/C, H2CONH4, ethyl acetate, 70ºC, reflux, 18h, %. Conclusions In this work were obtained iminosugar 8 (with six-membered ring) in four steps from D-ribose with an overall yield of 76 %. That procedure is a new and easy methodology to synthesized iminosugars. Iminosugars 6 and 7 was a potential compound for study biological activities because they have much free hydroxyl groups. In connection with the design and synthesis of new imino-C- nucleosides, we synthesized the imine 6, 7, and 8 in order to give the news bases to form imino-c-nucleosides. References 1- Dangerfield, E.; Plunkett, C.; Stocker, B.; Timmer,
M.; Molecules, 2009, 14, 5298-5307.
2- Wrodnigg, T.M.; Steiner, A.J.; Ueberbacher, B.J.; Anti-Cancer Agents Med. Chem., 2008, 8, 77-85.
3- Asano, N.; Nash, R.J.; Molyneux, R.J.; Fleet, G.W;
Tetrahedron Asymmetry, 2000, 11, 1645-1680. 4- Dwek, R.A.; Butters, T.D.; Platt, F.M.; Zitzmann, N.;
Nat. Rev. Drug Discov., 2002, 1, 65-75.
5- Cox, T.; Lachmann, R.; Hollak, C.; Aerst, J.; VAN Weely, S.; Hrebícek, M.; Platt, F.; Butters, T.; Dwek, R.; Moyses, C.; Gow, I.; Eltein, D.; Zimran, A.; Lancet, 2000, 355, 1481-1485.
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DESENVOLVIMENTO DE UMA FERRAMENTA ELECTROTÊXTIL PARA AFERIÇÃO DA QUALIDADE DO SONO ATRAVÉS DO ÍNDICE DE
PITSBURGH
Tavares, M. M.1, Belino, N.J.R.1, Patto, M. A. V.2 e Geraldes, M.J.O.1 1Universidade da Beira Interior, Departamento Ciência e Tecnologia Têxteis, Covilhã, PORTUGAL
2Universidade da Beira Interior, Departamento de Ciências da Saúde, Covilhã, PORTUGAL Resumo
O presente trabalho de investigação visa o desenvolvimento de uma nova solução tecnológica, com base em têxteis inteligentes, que nos permita estudar e estabelecer uma ligação entre o movimento noturno dos pacientes, com o estadiamento de algumas doenças neurodegenerativas, nomeadamente, Alzheimer, Parkinson´s e síndrome de Wittmaack Ekbom. Actualmente, o estudo do sono tem ganho uma enorme importância e, neste contexto, os investigadores envolvidos procuraram desenvolver uma ferramenta electrotêxtil, capaz de de captar a informação biomecânica dos pacientes durante o seu repouso nocturno e, simultaneamente, compará-la com o seu registro polissonográfico. Os dados recolhidos serão estatísticamente processados através de estudos de caso, para verificar a existência de uma relação entre a quantidade e tipologia dos movimentos efectuados, com o estadiamento da doença.
Introdução A revisão da literatura sobre o sono destaca a sua importância na manutenção de uma boa saúde física e mental. isto é claramente visível através dos vários estudos realizados por numerosas equipas de investigação a nível mundial. A título exemplifiucativo, podemos citar: 2003: Iglowstein et all Estudou o comportamento do sono da infância a adolescência e sua tendência futura; 2004: Ficca et all Estudou a importância do sono para a memória e Fredriksen et all Estudou a perda do sono em adolescentes ao longo do ensino médio na cidade de Chicago; 2005: Millman et all Estudou a sonolência excessiva em adolescente e adultos jovens, as causas, consequencias e formas de tratamento; 2006: Peppard et all Estudou a depressão originada de problemas respiratórios durante o sono; 2007: Rajaratnam Estudou os distúrbios do sono em oficiais de polícia; 2008: Phillip et all Estudou os distúrbios do sono relacionados a menopausa; 2009: Wagner et all Estudou a relação entre o stress crónico e os distúrbios do sono; 2010: Flagga et all Estudou as consequências socio económicas causadas pelos distúrbios do sono;
2011: Peever et all Estudou as potenciais causas dos distúrbios graves do sono e suas implicações na doença de Parkinson;
A tabela 1, mostra a enorme variedade de distúrbios do sono e a sua classificação de acordo com os parâmetros internacionais. (1)
Tabela 1 Classificação Internacional dos distúrbios do sono.
O estudo dos distúrbios do sono é geralmente realizado através de um exame polissonográfico, este exame avalia várias funções fisiológicas do paciente,(2,3), durante um período longo de tempo (várias horas). Num processo padronizado(2,3) de estudo do sono, é normalmente recolhida informação acerca da actividade eléctrica cerebral (eletroencefalograma - EEG); actividade eléctrica muscular (eletromiografia - EMG); actividade eléctrica cardíaca (electrocardiograma-ECG); actividade electromuscular gerada pelo olho (eletrooculograma-EOG), movimentos respiratórios (torácico-abdominais);
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fluxo oral e nasal; saturação de oxigénio no sangue e os batimentos cardíacos.
O foco deste trabalho situa-se no âmbito dos têxteis não convencionais. A grande variedade de aplicações, a elevada possibilidade de personalização e a excelente margem financeira, têm permitido uma taxa de crescimento contínuo e grande aceitação no mercado. Estas soluções tecnológicas são multidisciplinares, transversais a vários domínios científicos, constituindo, em muitas situações, avanços científicos relevantes em muitas áreas da engenharia.
Figura 1 Classificação sistemática dos têxteis não-convencinais.
O presente trabalho de investigação combina a engenharia têxtil com a medicina humana, particularmente, nos têxteis inteligentes aplicados à saúde (têxteis biomédicos, introduzindo alguns aspectos inovadores, quer ao nível nacional, quer ao nível internacional. Interessa ainda salientar a importância eo volume financeiro que a União Europeia tem colocado no financiamento deste tipo de contribuições ao nível V, VI e VII programa quadro, como por exemplo os projectos transnacionais: Wealthy, WearIT@work, My Hearth, Mermoth, Avalon, Biotex, Acteco, Proetex, Stella, OFSETH, Inteltex, Polyrtect, etc.
A equipa de investigação é constituída por duas entidades ligadas a Universidade da Beira Interior: a Faculdade de Engenharia que foi responsável pela produção das estruturas têxteis, e da componente eletrónica e de telecomunicações, e a Faculdade de Ciências da Saúde, que é responsável pela metodologia clínica e pelo estudo médico-epidemiológico, em estreita cooperação com os hospitais da Cova da Beira e Sousa Martins.
Materais e Métodos
Trata-se de um trabalho de investigação cujos objectivos principais podem ser enunciados da seguinte forma: 1 Desenvolver um sistema têxtil electroactivo que, de uma forma completamente automática e digital, proceda à detecção, classificação e registo dos movimentos dos pacientes durante o seu sono nocturno. 2 Desenvolver e promover um novo método de avaliação do estadiamento de doenças
neurodegenerativas, particularmente, em pacientes com Alzheimer, Parkinson ou síndrome de Wittmaack Ekbom. 3 Estimular a migração estratégica dos têxteis convencionais para uma área emergente, inovadora e de alto valor acrescentado.
A implementação prática deste trabalho de investigação, decorreu segundo um método não estritamente sequencial, com base num processo interactivo, em que as diferentes tarefas geraram conhecimento e/ou materiais para a afinação e reengenharia do protótipo produzido. Assim, o trabalho foi estruturado de uma forma modular e executado faseadamente. 1ª FASE - Protótipo de avaliação da cinesiologia dos pacientees. Esta etapa econtra-se completamente concluída, tendo consistido na produção e optimização de uma ferramenta electrotêxtil que permitisse a medição e registro dos movimentos nocturnos. O protótipo desenvolvido baseia-se numa estrutura compósita têxtil com o mesmo comprimento (1,9m), largura (0,9m) e espessura (5 cm) de um colchão normal aplicado em meio hospitalar, particularmente, na enfermaria dedicada ao estudo do sono. As especificações dos materiais têxteis foram pensadas de forma a permitir a concepção de um produto facilmente escalável para meio industrial e com custos controlados. Assim, de um conjunto de soluções tecnológicas passíveis de serem desenvolvidas, optou-se por uma estrutura compósita têxtil constituída por três camadas: camada superior, camada intermédia e camada inferior. A primeira e terceira camadas são camadas de protecção e de suporte, tendo sido construídas em espuma de poliuretano. A segunda camada - camada de sensorização é constituída por um tecido no qual estão incorporados fios condutores e uma matriz de sensores que foram colocados em áreas pré-determinadas, correspondendo às grandes zonas anatómicas do ser humano.
Figura 2 Ilustração esquemática da composição da estrutura electrotêxtil
A estrutura de sensorização(5,6,7) tem integrado um acelerómetro na zona do tronco, um na zona da anca, dois nas zonas das pernas, dois nas zonas dos braços e um para zona do pescoço e da cabeça. Cada sensor indica autonomamente não só a intensidade do movimento, mas também a sua direção, permitindo a geração de
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informações que serão recolhidas na forma de gráficos interativos e tabelas. A solução global desenvolvida para o sistema de sensorização, compreende ainda a existência de um centro de controlo (CC), um módulo de aquisição (MA) e um módulo de recolha e processamento de dados (MRP). O MA é directamente integrado na estrutura têxtil, sendo responsável pelo acondicionamento e aquisição dos sinais gerados pela rede de sensores, enviando-os para o MRP, onde se efectua um processamento prévio dos dados e posterior encaminhamento para o CC.(8)
Figura 3 Pormenor do módulo de aquisição.
Figura 4 Pormenor do módulo de recolha e processamento.
Em paralelo com o desenvolvimento dos módulos electrónicos foi construída uma solução de software, que faz a gestão completa de todo o processo, armazenando na base de dados a informação relevante e ,disponibilizando em tempo-real através de uma interface gráfica, a identificação e o número de movimentos para cada zona estudada para cada paciente. 2ª FASE Estudo clínico. Esta segunda etapa deste trabalha de pesquisa, jká se econtra completamente concluída e consistiu na definição dos critérios de inclusão e de exclusão; selecção e caracterização da população estudada (pacientes com doença de Parkinson); elaboração de inquéritos para avaliar a qualidade do sono; diagnóstico do estádio da doença; preenchimento e
entrega do formulário de consentimento informado; e qualificação dos recursos humanos para a manipulação dos sistemas de leitura de dados. 3ª FASE Recolha de dados. Esta fase consiste no registo simultaneo da informação polissonográfica e dos dados adquirido com o dispositivo electrotêxtil para cada paciente avaliado. Saliente-se que esta fase envolve um estudo multicêntrico de longo prazo, pelo que, embora tendo sido iniciada, irá decorrer pelo menos nos próximos 5 anos. 4ª FASE Análise estatística. Nesta fase procede-se ao processamento estatístico dos dados recolhidos com vista a verificar e, eventualmente, validar a existência de uma relação entre o número e tipologia dos movimentos com o estadio da doença neurodegenerativa.
Resultados e Discussão
A integração do sistema electrotêxtil encontra-se completamente validada, tendo sido montado e confeccionado um protótipo de teste, perfeitamente operacional, conforme ilustrado na figura 5.
Figura 5 Pormenor do sistema electrotêxtil desenvolvido. O estudo clínico foi iniciado no Hospital Sousa Martins como demonstra a figura 6.
Figura 6 Visualização de um ensaio clínico.
Observando o detalhe do hipnograma do paciente é possível verificar a existência de movimentos dos membros inferiores durante o decorrer do exame. Estes movimentos são detectados por eléctrodos colocados no músculo tibial das duas pernas. Na figura 7 podemos constatar que o paciente apresentou movimentos na perna
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direita o que também é visível no sistema electrotêxtil para no mesmo período temporal.
Figura 7 Pormenor da recolha de dados.
Figura 8 Pormenor da apresentação tabular de dados.
Figura 9 Pormenor da apresentação gráfica de dados.
Conclusões
Baseados nos resultados iniciais podemos considerar que a ideia subjacente a esta investigação apresenta um elevado potencial de sucesso. Se completamente sucedido, será possível o controlo ambulatório dos pacientes com as doenças neurodegenerativas estudadas. Consequentemente, existirá um aumento significativo do conforto do paciente, uma forte redução dos custos através da diminuição do número de dispendiosos exames. polissonográficos efectuados para acompanhamento destes doentes, uma diminuição de tempos de hospitalização e uma menor utilização de recursos humanos e materiais do SNS.
Referências
1) The International Classification of Sleep Disorders. Second Edition Diagnostic & Coding Manual American Academy of Sleep Medicine Westchester, IL, USA, 2005.
2) distúrbios do sono e parâmetros Subjetivos em
21(1):33-8. 3)
ciclo sono vigília e sua relação com a ansiedade em Estudos de Psicologia, 8,
37-43. 4)
Fiber Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0295,USA.
5) technologies for unobtrusive monitoring of vital
IEEE EMBS Annual International Conference New York City, USA, Aug 30-Sept 3, 2006.
6) M.Pacelli, G.Loriga., N.Taccini and R.Paradiso,
Biomechanical Variables: E-Proceedings of the 3rd IEEEEMBS International Summer School and Symposium on Medical Devices and Biosensors MIT, Boston, USA, Sept.4-6, 2006.
7) Piezoresistive Sensors for Biomechanical.
8) EMBS Annual International Conference, New York City, USA, Aug 30-Sept 3, 2006.
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Antibacterial properties of some naturally occurring phenols against Staphylococcus aureus
Â. Luís, A. P. Duarte, F. Domingues
CICS-UBI Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Covilhã, Portugal
Abstract
Micro-organisms exist as free-floating cells or, more often, in a community of cells attached to a substrate, referred to as biofilms. Staphylococcus aureus is a Gram-positive bacterium, which is pathogenic to both humans and animals and is able to form biofilms. This study was therefore undertaken to investigate for the first time the in vitro antibiofilm potential of gallic, caffeic and chlorogenic acids against S. aureus including clinical isolates of methicillin-resistant strains (MRSA). Gallic acid presented MIC of 4µg/mL for all the strains of S. aureus. Gallic acid at 4 mg/mL reduced the biofilm formation by about 40% for the strains of S. aureus ATCC 25923, MRSA10/08 and MRSA12/08. Caffeic and chlorogenic acid with the same concentration were able to reduce the biomass of biofilm by 80%.
Introduction
Micro-organisms exist as free-floating cells or, more often, in a community of cells attached to a substrate, referred to as biofilms. Biofilms allow micro-organisms to trap nutrients and withstand hostile environmental conditions, a key feature for their survival. Approximately 60% of human infections are reported to be a result of biofilm formation on human mucosa. These biofilms exhibit elevated resistance both to antibiotics and to the host defense systems, which often results in persistent and difficult-to-treat infections1. Staphylococcus aureus is a Gram-positive bacterium, which is pathogenic to both humans and animals and is able to form biofilms2. S. aureus biofilm formation contributes to its pathogenesis in a number of conditions, such as damaged skin infections, chronic and recurrent respiratory infections, osteomyelitis and mastitis, and to its colonization on the surface of undamaged skin3. Additionally, biofilms of staphylococci formed inside food plants pose a serious risk of food contamination2,3. Plant-derived compounds have gained widespread interest in the search for identify alternate substances for microbial control. These compounds are widely accepted because of the perception that they are safe and have long been used in folk medicine for the prevention and treatment of diseases and infections1. Previous research on plants and active constituents has almost exclusively focused on the effects of these against planktonic bacteria with little emphasis on the biofilms formed which are more resistant to antimicrobial agents and therefore more
difficult to control1. In our previous work, we identified some phenolics in plant extracts, allowing us to conclude that gallic acid, caffeic acid and chlorogenic acid were the major active compounds, responsible for the antimicrobial activity of those plant extracts4,5. Based in this knowledge, this study was therefore undertaken to investigate for the first time the in vitro antibiofilm potential of gallic, caffeic and chlorogenic acids against S. aureus including clinical isolates of methicillin-resistant strains (MRSA). The effect of phenolics was studied on biofilm formation and on the 24h-established biofilms, quantifying the total biomass of biofilm with crystal violet. Moreover the metabolic activity of biofilms was evaluated with XTT method. The Minimum Inhibitory Concentration (MIC) of pure phenolic compounds was assessed using CLSI standard protocols.
Materials and Methods
Test microorganisms and culture media Three strains of S. aureus were used in this study. S. aureus ATCC 25923, purchased from American Type Culture Collection (ATCC) and two clinical isolates of S. aureus resistant to methicillin, MRSA 10/08 and MRSA 12/08. Stock cultures were prepared and stored with 20% glycerol at -80ºC. The strains were sub-cultured on an appropriate agar plate 24 hours prior to any antimicrobial test and when cultured from stock, they were sub-culture before use. Brain Heart Infusion-Agar (BHI) was used for the growth of bacterial species. MIC determination The MIC value of pure phenolics (gallic, caffeic and chlorogenic acids) for the strains of S. aureus was determinated with the microdilution method according to the CLSI standard protocol (M7-A6). Biofilm susceptibility assay The biofilms of S. aureus were prepared in 96-well flat-bottom polystyrene microtiter plates, using a previously described method by Raja et al, 20116 with a few modifications. This method was similar to the MIC assay for planktonic cells. The bacterial suspensions were prepared from the overnight grown culture and the turbidity of the suspension was adjusted to 0.7 O.D. 610 nm 9 CFU/mL). Twofold serial dilutions of phenolics L volume in tryptone soya broth (TSB) supplemented with 0.5% glucose in the wells of 96-well flat bottom microtiter plate. Forty
87
microliters of fresh TSB with 0.5% glucose were added to each well, followed by the addition of of the above mentioned bacterial suspension. This resulted in the final inoculum of 6 × 107 CFU/mL in each well: the final concentrations of the compounds ranged from 4 to 0.5 mg/mL. The plate was incubated for 18 h at 37°C. After completion of incubation, the planktonic cells were removed from each well by washing two times with phosphate buffer saline (PBS). The biofilms were fixed with methanol for 20 min, stained with 0.1% (wt/vol) Crystal Violet for 10 min and rinsed three times with water. Biofilm formation was quantified by the addition of of 95% ethanol to the crystal violet stained wells and recording the absorbance at 595 nm using a microplate reader6. The effect of phenolics was also examined on preformed biofilms. The biofilms were prepared by inoculating the suspension of S. aureus into the wells of a polystyrene microtiter plate as mentioned above. After incubation at 37°C for 18 h, the culture supernatant from each well was decanted and planktonic cells were removed by washing the wells with PBS. Twofold serial dilutions of phenolic compounds were prepared in TSB and 1 L of each dilution was added to the biofilm in the wells. The plate was further incubated at 37°C for 18 h. The biofilm was fixed, stained and quantified as described above6. Quantitation of viable cells in the biofilm by XTT assay The 2H-tetrazolium-5-carboxanilide (XTT) assay was used to quantify the number of viable cells present in each of the biofilms formed in presence of phenolics and in those 24h-established biofilms following phenolics addition, in comparison with antimicrobial-free controls. The peg-plate was rinsed two times with PBS to remove loosely attached cells. The wells of a 96-well plate were filled with 120 µL of a filter-sterilized 100 µg/mL XTT and 10 µg/mL of phenazine methosulphate solution, the peg-plate was positioned into the wells and incubated at 37ºC in the dark for 3 h to allow the conversion of XTT into its formazan derivative. Reduction of XTT was then measured at 492 nm using a microtitre plate reader. The proportion of viable cells in treated biofilms was calculated by comparing the reduction of XTT with that of antimicrobial-free control biofilms7,8. Scanning electron microscopy Polystyrene coupons (1 cm × 1 cm) were individually washed and overnight submersed in a 70% ethanol solution. Prior to use, coupons were exposed to UV radiation for 30 min. S. aureus ATCC 25923 culture was grown overnight in TSB supplemented with 0.5 % glucose at 37ºC and then diluted in culture medium to an O.D. (610 nm) of 0.7. First, 300 µL of inoculum were added to each well of a 12-well tissue culture containing a coupon. Then 500 µL of 4 mg/mL gallic acid or caffeic acid solution and 200 µL of fresh culture medium were added to the wells. The plates were incubated 24 h at 37ºC. After that, the wells were washed two times with PBS and the samples were immediately fixed in a solution
of 4% formaldehyde and 2% glutaraldehyde in PBS for 3 h at room temperature. The coupons were then carefully washed with PBS, dehydrated in a graded ethanol series (25, 50, 70, 90 and 100%) and dried in a desiccator overnight. Finally, they were mounted on a stub, sputter coated with gold and documented with a scanning electron microscope (SEM) (Hitachi S-2700)9. Results and Discussion
S. aureus is clinically significant and the emergence of methicillin-resistant variants represents a major clinical concern. The ability of staphylococci to adhere on both eukaryotic cells and abiotic surfaces and to form biofilm are important virulence factors in chronic infections associated with implanted biomaterials, which are particularly difficult to eradicate. Table 1 shows the MIC values of the pure phenolics for the strains of S. aureus. Gallic acid presented MIC of 4µg/mL for all the strains of S. aureus. Caffeic and chlorogenic acids also possessed good MIC for S. aureus strains. The results now obtained, for antibiofilm activity, allowed us to conclude that gallic acid at 4 mg/mL reduced the biofilm formation by about 40% for the strains of S. aureus ATCC 25923, MRSA10/08 and MRSA12/08 (Figure 1). Caffeic and chlorogenic acid with the same concentration were able to reduce the biomass of biofilm by 80% (Figure 1). Regarding the effect against 24h-established biofilms, gallic acid did not have any effect on total biomass of biofilm for S. aureus ATCC 25923, but slightly decreased the biofilm biomass of both MRSA strains. However, caffeic and chlorogenic acids reduced the biofilm biomass almost 60%, when compared with the positive control, for all the strains of S. aureus. In what concerns the metabolic activity of S. aureus biofilms, when the biofilms were grown in the presence of the phenolic compounds, the metabolic activity of adherent cells was affected, even at low concentrations of the compounds. This effect was more pronounced in ATCC strain than in MRSA strains. When the compounds were additioned to 24-hours established biofilms, the metabolic activity also decreased and once again this reduction was more pronounced in ATCC strain, showing that MRSA strains were more resistant to the phenolic compounds (Table 2). The effect of caffeic and chlorogenic acids was more evident than gallic acid (Table 2). Morphogenesis of S. aureus biofilm cells was monitored by SEM (Figure 2). The results demonstrated the destruction of 3D structure of biofilm when the compounds are present in the biofilm formation. Cells exposed to 4 mg/mL of the phenolic compounds produced scant biofilms, which were composed only of a few bacteria cells. Moreover, in the presence of phenolics, it is possible to observe several damages in bacteria cell wall, leading to the loss of cocci shape, when compared with the biofilm of positive control.
88
0
0,2
0,4
0,6
0,8
1
1,2
O.D
. (59
5 nm
)
S. aureus ATCC 25923
0
0,2
0,4
0,6
0,8
1
1,2
O.D
. (59
5 nm
)
MRSA 10/08
0
0,2
0,4
0,6
0,8
1
1,2
1,4
O.D
. (59
5 nm
)
MRSA 12/08
Table 1 MIC values of pure phenolics compounds (modal values).
Figure 1 - Inhibition of biofilm formation by the phenolics at 4mg/mL.
Table 2 - Metabolic activity of 24h-established biofilms in presence of compounds at 4 mg/mL measured by XTT method (O.D. 492 nm)
(mean ± standard deviation).
MIC (mg/mL) Gallic Acid Caffeic Acid Chlorogenic Acid
S. aureus ATCC 25923 0.004 0.0625 0.5
MRSA 10/08 0.004 0.0625 0.5
MRSA 12/08 0.004 0.25 0.5
Compound S. aureus ATCC 25923 MRSA 10/08 MRSA 12/08
Gallic Acid 0.11 ± 0.05 0.11 ± 0.01 0.12 ± 0.02
Caffeic Acid 0.07 ± 0.01 0.07 ± 0.01 0.09 ± 0.02
Chlorogenic Acid 0.10 ± 0.05 0.10 ± 0.03 0.09 ± 0.05
Positive Control 0.31 ± 0.09 0.26 ± 0.10 0.22 ± 0.06
Negative Control 0.09 ± 0.03 0.10 ± 0.04 0.08 ± 0.04
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Conclusions
Gallic, caffeic and chlorogenic acids showed capacity to inhibit and eradicate biofilms of S. aureus including the methicillin-resistant strains. It is well known that S. aureus can secrete a number of exotoxins (e.g., hemolysins, enterotoxins, coagulase), which contributes to the ability of this pathogen to cause such a variety of diseases. The next step of this work will be the investigation of the effect of subinhibitory
-hemolysin production by the strains of S. aureus, using rabbit erythrocytes, which are 1000 times more sensitive to S. aureus -toxin than human erythrocytes.
Figure 2 SEM images. A: Uniformly distributed biofilm of S. aureus ATCC 25923 (positive control); B: Biofilm formed in presence of gallic acid; C: Biofilm formed in presence of caffeic acid. (Magnification of 7000×)
References
1. Sandasi, M., Leonard, C. M. & Viljoen, M. The in vitro antibiofilm activity of selected culinary herbs and medicinal plants against Listeria monocytogenes. Letters in applied microbiology 50, 30 5 (2010);
2. Qiu, J. et al. Subinhibitory concentrations of perilla oil affect the expression of secreted virulence factor genes in Staphylococcus aureus. PloS one 6, e16160 (2011);
3. Qiu, J. et al. Subinhibitory concentrations of thymol reduce enterotoxins A and B and alpha-hemolysin production in Staphylococcus aureus isolates. PloS one 5, e9736 (2010);
4. Ângelo Luís, Nuno Gil, Maria Emília Amaral, Fernanda Domingues, and A. P. Duarte. Ailanthus altissima (Miller) Swingle: A source of bioactive compounds with antioxidant activity. bioresources 7, 2105 2120 (2012);
5. Luís A, Domingues F, Duarte A. P. Bioactive Compounds, RP-HPLC Analysis of Phenolics, and Antioxidant Activity of Some Portuguese Shrub Species Extracts. Natural Product Communications 6, 1863 1872 (2011);
6. Raja, A. F. et al. Antistaphylococcal and biofilm inhibitory activities of acetyl-11-keto- -boswellic acid from Boswellia serrata. BMC microbiology 11, 54 (2011);
7. Smith, K., Perez, A., Ramage, G., Gemmell, C. G. & Lang, S. Comparison of biofilm-associated cell survival following in vitro exposure of meticillin-resistant Staphylococcus aureus biofilms to the antibiotics clindamycin, daptomycin, linezolid, tigecycline and vancomycin. International journal of antimicrobial agents 33, 374 8 (2009);
8. Paiva, L. C. F., Vidigal, P. G., Donatti, L., Svidzinski, T. I. E. & Consolaro, M. E. L. Assessment of in vitro biofilm formation by Candida species isolates from vulvovaginal candidiasis and ultrastructural characteristics.
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9. Jiang, C., Schaudinn, C., Jaramillo, D. E., Webster, P. & Costerton, J. W. In Vitro Antimicrobial Effect of a Cold Plasma Jet against Enterococcus faecalis Biofilms. ISRN dentistry 2012, 295736 (2012).
Acknowledgements
Ângelo Luís acknowledges a fellowship from Fundação Para a Ciência e a Tecnologia (Reference: SFRH / BD / 65238 / 2009), co-funded by Fundo Social Europeu (POPH QREN) and by national funds of Ministério da Educação e Ciência. Authors wish to thank to Eng. Ana Paula Gomes, from the Centro de Óptica of the Universidade da Beira Interior for the help in SEM images acquisition.
A
B
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Preparation and Characterization of TiO2/WO3 nanocomposites films for photocatalytic applications L.C. Silva1, M.E. Melo Jorge2, S. Sério1
1 CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, 2 Departamento de Química e Bioquímica/Centro de Ciências Moleculares e Materiais, Faculdade de
Ciências, Universidade de Lisboa, Campo Grande C8, 1749-016 Lisboa, Portugal. Abstract TiO2/WO3 and WO3/TiO2 nanocomposites films were deposited on glass substrates by DC-magnetron sputtering. The structures, morphologies and optical properties of TiO2 and WO3 layers and also of the bilayered films were studied by X-ray diffraction, field emission scanning electron microscopy and UV–Vis spectroscopy. It was found that the nanocomposite films exhibit good adherence to the substrates and high mechanic stability. In both nanocomposites independently of the above layer, the main phase observed in the X-ray patterns corresponds to WO3 and the optical properties are similar to the WO3 layer transmittance, therefore expected to be photocatalytic active under visible irradiation. Introduction In recent years, the pollution of the wastewaters with dyes is becoming a major environmental problem due to the growing use of a variety of dyes. Dyes usually have a synthetic origin and complex aromatic molecular structures which are more stable and more difficult to biodegrade. It is known that wastewaters containing dyes are very difficult to treat, since they are molecules (particularly azo dyes) resistant to aerobic digestion and are stable to oxidizing agents. Textile, paper, plastics, and cosmetic industries use a wide variety of dyes to colour their products and discharge large amount of colour effluents which are very toxic and can cause serious ecological problems. Consequently there has been an increasing interest in developing new methods, more effective than the conventional processes, commonly used, to eliminate these environmental contaminants. Advanced oxidation processes (AOP), characterized by the production of hydroxyl radicals (OH.) and superoxide anion (O2
-), which are generated when a semiconductor catalyst absorbs radiation when it is in contact with water and oxygen are a promising technology in which a broad range of organic dyes can be oxidized quickly and non-selectively. Among various photocatalysts TiO2 has been intensively studied due to its inertness, nontoxicity, strong oxidizing activity and chemical stability [1,2]. Nevertheless two limitations are recognized for a wide practical application, such as the small percentage of the solar radiation, which has the required energy to photogenerate electrons and holes and their high recombination rate. A lot of researches have be done to improve the TiO2 photocatalyst activity and show that the efficiency of the photocatalytic reaction can be enhanced in heterogeneous semiconductors systems because the
recombination of photogenerated charge carriers are suppressed due to directional transfer of the photogenerated charges between different types of semiconductor particles [3-5]. So, a proficient way to extend the absorbance of TiO2 to visible light is the composite of different nano-semiconductors including Fe2O3-TiO2, TiO2-SnO2, ZnO-TiO2 and WO3-TiO2 [6-9]. These studies show a synergistic photocatalytic effect for a suitable combination of the semiconductors. Photocatalysts can either be used as powders in a slurry form or as supported films. The latter configuration is advantageous since solves important problems such as the need for separation/filtration steps, the problematic use in continuous flow systems and the particles aggregation. Investigations on heterogeneous photocatalysis have been oriented towards the photocatalyst immobilization in film form. Many techniques can be used to prepare catalytic material immobilized in film form [10-13] such as, sol-gel method, chemical vapor deposition, sputtering and others. Among them sputtering method presents several advantages mainly because the structure, crystallinity, morphology and optical properties of sputtered films can be modified by changing the deposition parameters [14]. This work reports some results of the preparation and characterization of TiO2/WO3 and WO3/TiO2 nanocomposites films for photocatalytic applications. Materials and Methods TiO2/WO3 and WO3/TiO2 composite films were deposited by DC-reactive magnetron sputtering on glass substrates in a custom made system. Prior to the deposition, the substrates were cleaned successively in acetone, isopropanol and deionized water for 5 min each step and dried with nitrogen gas to remove any organic contamination. A turbomolecular pump was used to achieve a base pressure of 10-4 Pa (before introducing the gas mixture). Before the sputter-deposition step of the films, a movable shutter was interposed between the target and the substrates, and the target was pre-sputtered in Ar atmosphere for 5 min to clean the target surface. The target-to-substrate distance was kept constant at 100 mm. The gases in the system were 99.99% pure Ar and O2 and the partial pressures of these gases were separately controlled by mass flow controllers. One reference sample of TiO2 film was deposited on a glass substrate using a metallic titanium disc (99.99% purity) as sputtering target. The total pressure, PT, was kept constant at 0.8 Pa and the partial pressure of oxygen was set at 0.08 Pa (10% of PT). The sputtering power was 1000 W and the deposition time was 80 min. In the case of the tungsten
91
oxide film, the total pressure, PT, was kept constant at 1.2Pa and the partial pressure of oxygen was set at 0.6 Pa (50% of PT). The sputtering power used was 350 W and the deposition time was 25 min. The TiO2/WO3 and WO3/TiO2 composite films were prepared using the same deposition conditions of the reference films. The structural characterization of the films was carried out by X-ray diffraction (XRD) on a Philips Analytical PW 3050/60 X’Pert PRO (theta/2 theta) equipped with X’Celerator detector and with automatic data acquisition (X’Pert Data Collector (v2.0b) software), using a monochromatized CuK� radiation as incident beam, 40 kV–30 mA. Diffractograms were obtained by continuous scanning in a 2�-range of 10º to 90º with a 2�-step size of 0.02º and a scan step time of 20 s. The surface morphology and thickness of the films were examined by field-emission scanning electron microscope (FEG-SEM JEOL 7001F). In order to prevent charge build up during analysis a thin chromium film was coated on the films. The optical properties of the films were measured with Shimadzu UV b - 2101PC UV/VIS spectrophotometer at room temperature within the wavelength range 300-900 nm.
Results and Discussion The structural characterization revealed that the as-prepared TiO2 and WO3 films are amorphous or poorly crystallized. In order to allow the crystalline growth, the films were thermal annealed at 400ºC in air during 4h. The XRD patterns, for the annealed TiO2 and WO3 films, are presented in Figure 1. For the TiO2 film the XRD pattern show relative sharp peaks indicating the coalescence of nanocrystalline anatase-phase TiO2 and exhibit a preferred orientation along the (004) direction. In the case of the WO3 film, the diffraction peaks were assigned to the monoclinic WO3 phase, which gave the best fit. However, triclinic, orthorhombic and monoclinic diffraction peaks almost overlap for many 2� values, namely the (002), (020) and (200) reflections at 2� around 23-24º and it is difficult to discriminate between these three phases. On the other hand, according to the phase diagram, the monoclinic and triclinic structures are the most common and coexist in WO3 at temperatures lower than 500 °C, the orthorhombic phase between 330 and 740 °C and, finally, a tetragonal structure up to 1230 °C [15]. Earlier studies show that the diffraction pattern features at 2� around 23-24º can indicate a mixture of the orthorhombic and the monoclinic room temperature WO3 phases [16], but can also arise from preferred orientation or from the presence of crystallographic shear planes [17]. Therefore, in the WO3 films it cannot be discarded the presence also of the triclinic and orthorrombic phases considering the aforementioned reasons. The inset in figure 1 shows the surface morphology of the annealed WO3 film investigated by SEM. The image shows agglomerates of grains or particulates, with spherical shape and average sizes of 100–250 nm
distributed over the substrate surface with a ‘bloomingflower-like’ appearance and others with elongated shape. Figure 2 shows the XRD patterns of the TiO2/WO3 and WO3/TiO2 nanocomposites films. Comparing figure 1 and figure 2 it can be observed that the XRD patterns of the nanocomposite films exhibit a main phase attributed to the monoclinic WO3 phase (also as the WO3 reference film, the presence of the triclinic and orthorrombic phases cannot be discarded) and only a small evidence of the anatase TiO2 is observed in both nanocomposites independently of the above layer.
Figure 1 XRD patterns of the annealed TiO2 film deposited at 10% in Ar/O2 mixture and P = 1000 W and of the annealed WO3 film deposited at 50% in Ar/O2 mixture and P = 350W. The inset corresponds to a SEM image of the surface of the annealed WO3 film.
Figure 2 XRD patterns of the TiO2/WO3 and WO3/TiO2 nanocomposites films annealed at 400ºC. �- corresponds to the anatase TiO2 phase.
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The surface morphology of the nanocomposite films was investigated by SEM and the images are depicted in figure 3. When the above layer is WO3 the film morphology consist of agglomerates of nano-sized grains or particulates, distributed over the substrate surface with a ‘blooming flower-like’ appearance (see Fig. 3a) and an average size of 300-500 nm. In the case of the nanocomposite film with the TiO2 layer as the upper layer (see Fig. 3b), the surface morphology is completely different although are visible agglomerates considerably smaller in comparison with the other nanocomposite with the WO3 layer above. It is also noticeable a less dense surface with voids between the agglomerates. The thicknesses were evaluated from FE-SEM cross-section images of the TiO2 thin films, which are presented as inset of the corresponding films. The thicknesses of TiO2 and WO3 layers were approximately 990 nm and 2100 nm, respectively, in both nanocomposites independently of the order of the layers.
Figure 3 SEM images of the surface of the TiO2/WO3 and WO3/TiO2 nanocomposites films. The cross-section images of the nanocomposite films are presented as inset.
Figure 4 shows the optical transmittance spectra of the TiO2, WO3 and of the bilayered films. The transmittance spectrum of the reference TiO2 film shows the usual interference pattern in the range of low absorption with a sharp fall of transmittance at the band edge around 350 nm. The annealed WO3 film is light yellowish and nearly transparent. The band edge of WO3 film is around 500 nm. The transmittance spectra of the TiO2/WO3 and WO3/TiO2 bilayered systems show almost similar nature as the WO3 film. The average transmittance of TiO2, WO3, and TiO2/WO3 and WO3/TiO2 are 90%, 60%, and 58%, respectively.
Figure 4 Optical transmittance spectra of the TiO2, WO3 reference films and of the TiO2/WO3 and WO3/TiO2 nanocomposites films. The optical band-gap of the TiO2, WO3 reference films were determined from the transmission spectra using Tauc’s relation [18], given as
(1) where, ( =1239/λ) is the excitation energy (in eV), with the wavelength λ in nanometers and m is a parameter accounting for the different band-gap transition modes, is the optical energy band-gap, and α is the absorption coefficient (in cm−1), which is obtained near the absorption edge from the transmittance, T, using the equation
(2)
where d is the thickness of the film [19]. In Eq. (1), the exponent m depends upon the type of optical transitions in the material. For indirect transitions, which is the case of TiO2 and WO3 films, the exponent takes the value [18], m = 2. The optical energy band-gap was determined to be 3.33 eV for the TiO2 reference film, whereas the optical energy
300 400 500 600 700 800 9000
10
20304050
607080
90100
T /%
� /nm
TiO2
WO3
TiO2/WO
3
WO3/TiO
2
93
band-gap for the WO3 reference film comes out to be 1.97 eV. These values are in agreement with the published results for these type of oxides [14, 20] and also evidence that the TiO2 and WO3 will be activated in the UV and visible range, respectively. Since the optical transmittance spectra of the TiO2/WO3 and WO3/TiO2 bilayered films exhibit similar evolution as the WO3 reference film and also considering the good performance of TiO2 [21] and WO3, on the Rh6G photodegradation process under UV–vis radiation, the photodecolorization of this pollutant, using the nanocomposites films, is now in progress under visible radiation. Conclusions TiO2/WO3 and WO3/TiO2 bilayered films were deposited on glass substrates by DC-reactive magnetron sputtering. The nanocomposite films exhibit good adherence to the substrates and high mechanic stability. In both composites independently of the above layer, the main phase observed in the X-ray patterns corresponds to the WO3. The nanocomposites transmittance is similar to WO3 transmittance and therefore is expected that they will be active under visible light irradiation. References 1. Mills, A., Le Hunte, S., J. Photochem. Photobiol., A,
108, 1, 1997. 2. Grätzel, M., Nature, 414, 338, 2001. 3. Akhavan, O., Appl. Surf. Sci., 257, 1724, 2010. 4. Krishnamoorthy, S., Baker, J. P., Amiridis, M. D.,
Catal. Today, 40, 39, 1998. 5. Nova, I., Lietti, L., Tronconi, E., Forzatti, P., Catal.
Today, 60, 73, 2000. 6. Lin, C. F., Wu, C. H., Onna, Z. N., J. Hazard. Mater.,
154, 1033, 2008. 7. Marci, G., Augugliaro, V., López-Munoz, M. J.,
Martín, C., Palmisano, L., Rives, V. Schiavello, M., Tilleyand, R. J.,Venezia, A. M., J. Phys. Chem. B, 105, 1033, 2001.
8. Keller, V., Bernhardt, P., Garin, F., J. Catal., 215, 129, 2003.
9. Akhavan, O., Azimirad, R., Appl. Catal., A, 369,77, 2009.
10. Kavan, L., Grätzel, M., Electrochim. Acta, 40, 643, 1995.
11. Shaogui, Y., Xie, Q., Xinyong, L., Yazi, L., Shuo, C, Guohu, C., Phys. Chem. Chem. Phys., 6, 659, 2004.
12. Sánchez - Mora, E., Gómez - Barojas, E., Gracia-Jiménez, J. M., Silva- González, R., Pérez- Rodríguez, F., Phys. Status Solidi C, 1, S116, 2004.
13. Celik, E., Yildiz, A. Y., Ak Azem, N. F., Tanoglu, M., Toparli, M., Emrullahoglu, O.F., Ozdemir, I., Mater. Sci. Eng., B, 129, 193, 2006.
14. Sério, S., Melo Jorge, M. E., Maneira, M. J. P., Nunes, Y., Mater. Chem. Phys., 126, 73, 2011.
15. Naidu, S. V. N., Rao, P. R., Phase Diagrams of Binary Tungsten Alloys, Indian Institute of Metals, Calcutta, 1991.
16. Marsen, B., Cole, B., Miller, E. L., Sol. Energy Mater. Sol. Cells, 91, 1954, 2007.
17. Jimenez, I., Arbiol, J., Dezanneau, G., Cornet, A., Morante, J. R., Sens. Actuators, B, 93, 475, 2003.
18. Tauc, J., Amorphous and Liquid Semiconductors, Plenum, London, 1974.
19. Mardare, D., Tasca, M., Delibas, M. and Rusu, G. I., Appl. Surf. Sci., 156, 200, 2000.
20. González-Borrero, P. P., Sato, F., Medina, A. N., Baesso, M. L., Bento, A. C., Baldissera, G., Persson, C., Niklasson, G. A., Granqvist, C. G., Ferreira da Silva, A., Appl. Phys. Lett., 96, 061909, 2010.
21. B. Barrocas, O. C. Monteiro, M. E. Melo Jorge, S. Sério, Appl. Surf. Sci., 264, 111, 2013.
Acknowledgements The authors acknowledge the financial support from Fundação para a Ciência e a Tecnologia (FCT), for the projects PEst-OE/FIS/UI0068/2011 and PEst-OE/QUI/UI0536/2011. S. Sério for the Programme Ciência 2007.
94
Photocatalytic degradation of Rhodamine 6G by nanocrystalline Ca0.6Ho0.4MnO3 film under visible light
B. Barrocas1, A. Rovisco2, Y.Nunes2, S. Sério2, M.E. Melo Jorge1
1CCMM, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal, 2CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de
Lisboa, 2829-516 Caparica, Portugal.
Abstract
In this work, the perovskite (Ca0.6Ho0.4MnO3) film was prepared by RF-magnetron sputtering from nanosized powder target previously prepared by self-combustion method using citric acid and the catalytic activity was examined on the decolorization of Rhodamine 6G (Rh6G) aqueous solutions. The Ca0.6Ho0.4MnO3 film showed a promising photocatalytic performance under visible light irradiation, with very low variation of decay rate after two consecutive usages. The structural and morphological characterization was performed by XRD and DRIFTS, and revealed high stability of the film after two successive photodegradations assays.
Introduction
Textile and industrial dyes are a major source of water contamination and therefore, many methods have been used for the purification of water contaminated with dyes [1]. The most efficient method for water purification, destroying organic pollutants is heterogeneous photocatalysis [2]. Many materials have been studied and tested for use as catalysts in photodegradation studies, such as TiO2, CdS, WO3 and others, but the TiO2 is one of the most studied semiconductors for photocatalytic reactions because it shows a high reactivity under ultraviolet (UV) light and it is nontoxic, stable and inert chemically. However, TiO2 only becomes active under irradiation with ultraviolet UV light whose energy exceeds the band gap of 3.2 eV in the anatase crystalline phase. This inhibits the utilization of solar light as a sustainable energy source for TiO2 activation because only 5 % of the incoming solar energy
s surface is in the UV range [3-5]. In this context, it is important to search other alternative materials that can have a photoresponse in the visible range. Ternary metal oxides with different crystal structures show excellent photoactivity due to the orientation of atoms in a layer structure and the presence of vacancies in the crystal structure. For example, different crystal structures such as perovskites (ABO3), pyrochlores (A2B2O7), spinels (AB2O4), and delafossites (ABO2) are of interest as photocatalysts [6]. Therefore, perovskites are a family of interesting compounds that can offer the desired properties for an ideal photocatalyst. Recently, perovskites have been explored as potential materials for photocatalytic applications. Compounds like
LaNiO3, CeAlO3 [1], CeVO3, PrVO3, NdVO3 [7], SrFeO3 [8], SrTiO3, NaTaO3, NaNbO3, KNbO3 and KTaO3 [9] have been reported to have p-type semiconductor characteristics and, for that reason, they are photocatalytically active using UV and visible light [10]. The band structure of the perovskites has been reported to be responsible for making the perovskites photocatalytically active [11]. Therefore, it is desirable to explore the photocatalytic properties of perovskites [1, 12]. The general formula of manganite perovskite-type structure is A1-xLnxMnO3 (A = alkaline earth, Ln= rare earth) [13]. In this work the Ca0.6Ho0.4MnO3 catalyst was prepared with perovskite structure, by RF-magnetron sputtering using nanosized powder target. This work reports also some preliminary results of the photodegradation under visible light of Rh6G using the Ca0.6Ho0.4MnO3 film.
Materials and Methods Ca0.6Ho0.4MnO3 film was deposited at room temperature by RF-magnetron sputtering from a nanosized powder target previously prepared by self-combustion method using citric acid, as described in detail in previous works [15, 16]. The sputtering target was prepared by mixing the synthesized powder with acetone. The mixture was placed on the cathode top and it was pressed and compacted until the acetone evaporation. The target was sputtered in 99.999% pure argon at constant total sputtering gas pressure (PTot) of 0.23 Pa and the deposition time was 80 min. It was used a RF power supply: Plasmaloc 2HF and the deposition was done using a sputtering power of 25 W and frequency = 100 KHz. The manganite film was deposited on an unheated fused silica substrate. In order to allow the crystalline growth, the film was annealed at 800 ºC in air during 6 h. The structural characterization of the film was carried out by X-ray diffraction (XRD) on a Philips Analytical PW
th
monochromatized CuK radiation as incident beam, 40 kV 30 mA. Diffractograms were obtained by continuous scanning in a 2 -range of 10º to 90º with a 2 -step size of 0.02º and a scan step time of 20 s. The surface morphology and thickness of the film was examined by field-emission scanning electron microscope (FEG-SEM JEOL 7001F). In order to prevent charge
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build up a thin gold film was coated on the film during analysis. For a detailed study of the surface, an atomic force microscope (AFM) was used, AFM Topometrix TMX 2000 (Veeco Instruments), in contact mode. Silicon cantilevers were employed. The images were taken with 400×400 pixels resolution and with an area of 1×1 µm2. A one step-leveling was applied to the images for accurate measurement of Z-height across a sample without adding any erroneous tilt information to the data and the root mean square roughness (Rrms) was calculated by Topometrix software. All the photodegradation experiments were conducted using a 250 mL refrigerated photoreactor [2]. The radiation source used was a 450 W Hanovia medium-pressure mercury-vapour lamp, the total irradiated energy being 40-48% in the ultraviolet range and 40-43% in the visible region of the electromagnetic spectrum. A glass filter was used in order to eliminate the UV radiation. The catalytic photodegradation assays were performed using Ca0.6Ho0.4MnO3 film with geometric area (9.75 cm2) into 175 mL of 5 ppm R6G aqueous solution. Prior to irradiation, the solutions were stirred in darkness for 1 h to ensure the adsorption equilibrium. During irradiation, with visible light, the solutions were sampled at regular intervals and analyzed by UV-vis spectroscopy. A UV-vis spectrophotometer Shimadzu UV-2600 was used for monitoring the absorption of the Rh6G solutions and the rate of decolorization was observed in terms of change in intensity at (526 nm). The decolorization photocatalytic efficiency (%) has been calculated as:
where is the initial concentration of dye and is the concentration of dye after photoirradiation. In order to study the reusability of the catalysts, all the experimental parameters were kept constant and the experiments were repeated for 2 sets using the same catalyst and fresh dye solutions. After each photodegradation assay the catalyst was cleaned with distilled water to remove any organic contamination. The films structural stability was also checked after each photodegradation assay by XRD. The surface of the catalyst was studied using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) before de photocatalytic assays and after each reuse. The diffuse reflectance infrared Fourier transform spectra (DRIFTs) were obtained on a Nicolet 6700 FT-IR attached to Smart Diffuse Reflectance Accessory, in the region 400-4000 cm-1. The background was done using a gold plate and the data acquisition was performed using the program Omnic. Results and Discussion
The XRD pattern for the annealed manganite film depicted in figure 1, revealed the formation of perovskite-
type phase with orthorhombic symmetry, space group Pnma.
Figure 1 - XRD patterns of the annealed manganite (Ca0.6Ho0.4MnO3) film deposited in fused silica substrate.
The surface morphology of the Ca0.6Ho0.4MnO3 film was analyzed with SEM and AFM techniques (Figure 2). Both techniques show a film with a smooth and homogeneous surface texture, with a surface roughness of approximately 1.09 nm. The film presents a thickness of 890 nm.
a)
b)
Figure 2 a) SEM images (surface and cross-sectional image) b) AFM images (two- and three-dimensional images) of the Ca0.6Ho0.4MnO3 film.
To study the catalytic activity, the film was tested in the photodegradation of an organic dye, Rh6G. For comparative purposes the Rh6G photolysis (without any catalyst) was also performed.
10 20 30 40 50 60 70 80 90
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. u.
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Figure 3 shows typical time dependent UV vis spectra of Rh6G decolorization with annealed Ca0.6Ho0.4MnO3 film catalyst during 8 hours of visible light irradiation.
Figure 3 - Absorbance spectra of Rh6G solution during the first photodegradation experiment, using the Ca0.6Ho0.4MnO3 film as catalyst.
Rh6G presents the main absorption peaks at 526 nm in visible region and 276 and 343 nm in UV region. The rate of decolorization was recorded with respect to the change in intensity of absorption peak at 526 nm. During the 8 hours of irradiation this absorption peak diminished, indicating that the dye has been degraded. Using the data from the UV-vis spectra obtained after each degradation was possible to represent graphically the photodegradation curves of 175 mL aqueous solution of 5 ppm Rh6G over time. The obtained results are present in Figure 4.
Figure 4 - Rh6G degradation percentage evolution during the several photocatalytic degradations of a 5 ppm aqueous solution for the Ca0.6Ho0.4MnO3 film.
As can be seen from Figure 4 the material tested demonstrated to be catalytic in this photodegradation process. After 8 hours of irradiation with visible light no significantly Rh6G was detected in the solution. It can be observed that the Ca0.6Ho0.4MnO3 film, when used for the first time, could degrade 91.5% dye, with a very small change to 90.9% in the efficiency when used for second time. This result reveals that Ca0.6Ho0.4MnO3 film to be good dye-decolorizing using visible light and a promising catalytic after two consecutive usages. To evaluate the film photochemical stability after successive photodegradations assays it was performed the structural characterization by XRD and DRIFT spectra, after each degradation and the obtained results are depicted in Figures 5 and 6, respectively. The XRD data of the reused Ca0.6Ho0.4MnO3 film shows that there were no additional phases and the data matched with the fresh Ca0.6Ho0.4MnO3.This indicated that Ca0.6Ho0.4MnO3 film did not leach out/corrode after reusing it in two consecutive assays. It can also be observed that the crystalline structure of the film remains the same after the successive degradations. The DRIFTS data of the reused Ca0.6Ho0.4MnO3 film shows the absence of any organic species on the film surface.
Figure 5 - XRD patterns of the Ca0.6Ho0.4MnO3 film after each photodegradation experiment.
Figure 6 DRIFTS spectra of the Ca0.6Ho0.4MnO3 film after each photodegradation experiment.
0
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Therefore, the reuse of the Ca0.6Ho0.4MnO3 film show a promising performance not only in the stability but also with very low variation of decay rate after two consecutive usages.
Conclusions The reuse of Ca0.6Ho0.4MnO3 manganite film prepared by magnetron sputtering technique using nanosized powder compacted target was evaluated in the degradation of Rh6G. Under visible light irradiation the Ca0.6Ho0.4MnO3
film has worked efficiently to degrade Rh6G in aqueous phase. The film show a promising catalytic performance without significant decrease in the removal efficiency after two consecutive usages. XRD revealed high stability of the films after successive photodegradations assays and DRIFTS revealed that the film has no adsorbed organic species on the surface.
References
1. Deshpande, P., Aruna, S., Mandas, G., Clean - Soil, Air, Water, 39, 259, 2011.
2. Franco, A., Neves, M., Ribeiro Carrott, M., Mendonça, M. H., Pereira, M. I., Monteiro, O. C., J. Hazard. Mater., 161, 545, 2009.
3. Zhao, S., Li, J., Wang, L., Wang, X., Clean - Soil, Air, Water, 38, 268, 2010.
4. Chen, P., Zhang, X., Clean - Soil, Air, Water, 36, 507, 2008.
5. Bhatkhande, D., Pangerkar, V., Beenackers, A., J. Chem. Technol. Biotechnol., 77, 102, 2001.
6. Murugesan, S., Huda, M., Yan, Y. Al-Jassim, M., Subramanian, V., J. Phys. Chem. C, 114, 10598, 2010.
7. Saha, D., Mahapatra, S., Row, T., Madras, G., Ind. Eng. Chem. Res., 48, 7489, 2009.
8. Yang, Y., Cao, Z., Jiang, Y., Liu, L., Sun, Y., Mater. Sci. Eng., B, 132, 311, 2006.
9. Huang, Y., Xie, Y., Fan, L., Li, Y., Wei, Y., Lin, J., Wu, J., Int. J. Hydrogen Energy, 33, 6432, 2008.
10. Li, Y., Yao, S., Wen, W., Xue, Z., Yan, Y., J. Alloys Compd., 491, 560, 2010.
11. Kim, T., Hur, S., Hwang, S., Park, H., Park, Y., Choi, W., Choy, J-H., Mater. Res. Bull, 42, 1914, 2007.
12. Deshpande, P., Madras, G., Chem. Eng. J., 158, 571, 2010.
13. Ferreira, B. M., Melo Jorge, M. E., Lopes, M. E., Nunes, M.R., Silva Pereira, M.I., Electrochimic. Acta, 54, 5902, 2009.
14. Sério, S., Melo Jorge, M. E., Maneira, M. J. P., Nunes, Y., Mat. Chem. Phys., 126, 73, 2011.
15. Sousa, D., Nunes, M. R., Silveira, C, Matos, I., Lopes, A. B., Melo Jorge, M. E., Mater. Chem. Phys., 109, 311, 2008.
16. Isasi, P. H., Lopes, M. E., Nunes, M. R., Melo Jorge, M. E., J. Phys. Chem. Solids, 70, 405, 2008.
Acknowledgements Financial support from FEDER, through Programa Operacional Factores de Competitividade COMPETE, and Fundação para a Ciência e a Tecnologia FCT, for the project PTDC/AAC-AMB/103112/2008. The authors acknowledge the financial support FCT, for the projects PEst-OE/FIS/UI0068/2011 and PEst-OE/QUI/UI0536/201. S. Sério for the Programme Ciência 2007.
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Antioxidant activity of solvent extracts from Vitex agnus-castus L.
Diogo Pereira1, Calrla Gaiolas, Jesus Rodilla, Rosalina Mata, Lúcia Silva1
1Chemistry Department, Unity of Textile & Paper Materials, University of Beira Interior, 6201-001- Covilhã, Portugal
Abstract
Vitex agnus-castus L. is a plant of the family of Verbenaceae, common in the Mediterranean and Africa, biological activities. In this study we will evaluate the antioxidant activity of solvent extracts from the plant using the colorimetric method of the DPPH. The result suggests a strong antioxidant activity, being ethanol the best solvent for the extraction of these species.
Introduction
Vitex agnus-castus L. (Verbenaceae) is a widely distributed plant that grows on the Mediterranean and Africa. This plant has a wide range of biological activities such as regulation of menstrual cycle, acne, cytotoxic activity against human cancer cells, diuretic, sedative, among others. [3, 4]
Oxidative stress is an unbalance of the produced oxidative species and the antioxidant species, resulting in a vast roll of diseases like cancer, atherosclerosis, inflammatory processes and neurodegenerative processes, all linked to the aging process. There are very plants and compounds known with antioxidant activity, and the number of reported plants is increasing over the years, not only for stronger antioxidant species but also for accessible, and easy to reproduce compounds. [2] Flavonoids and phenolic acids are common in plants, and they have been reported with great antioxidant activity. [2, 3] The aim of this study was to investigate the antioxidant activity of solvent extracts from the leaves of Vitex agnus-castus L. Materials and Methods
Experimental general proceedings
All the solvents and used reagents were analytically pure. The measures of absorption were done using a spectrophotometer UV-Vis Evolution 160 at 517nm. Plant material Vitex agnus-castus L. was collected in Angola, by the Faculty of Science, Herbalist of Luanda and a sample was sent to University of Beira Interior. The plant was air-dried before the extraction. Solvent extraction The sequential extraction was made with solvents with growing polarity with the use of a Soxhlet, The solvents used was hexane, dichloromethane, ethyl acetate and ethanol. The extractions were made with 20g of leaves. DPPH (2,2-diphenyl-1-picrylhydrazyl) method The method used for evaluation of the antioxidant activity was the DPPH method. This reaction consists on the colour decrease when the odd electron of the nitrogen atom in DPPH·
is reduced by receiving a hydrogen atom from the antioxidants compounds, this will decrease the original purple colour. The results are expressed in IC50 (concentration that provides 50% inhibition) and AAI that is calculated with the mass of DPPH and the IC50. It is considering weak antioxidant activity when the AAI<0.5, moderate between 0.5 and 1, strong between 1 and 2, and very strong above 2. [1] Results and Discussion
The results of the antioxidant activity are present in table 1, the antioxidant activity was poor in the hexane extract, moderate in dichloromethane and ethyl acetate and strong in the ethanol extract
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Table 1 Results of IC50, AA1 and classified antioxidant activity according to concentration of DPPH and solvent chosen.
Concentration of
DPPH (mM) IC50 AA1 Antioxidant Activity
Hexane
0,04 45,254 0,348 Poor
0,06 55,517 0,426 Poor
0,08 68,579 0,460 Poor
0,1 83,335 0,473 Poor
Dichloromethane
0,04 34,496 0,457 Poor
0,06 41,776 0,566 Moderate
0,08 48,700 0,647 Moderate
0,1 57,015 0,691 Moderate
Ethyl Acethate
0,04 18,748 0,841 Moderate
0,06 24,315 0,972 Moderate
0,08 33,197 0,949 Moderate
0,1 47,694 0,826 Moderate
Ethanol
0,04 16,417 0,960 Moderate
0,06 20,022 1,181 Strong
0,08 24,187 1,303 Strong
0,1 27,537 1,431 Strong
Conclusions
The leaves of Vitex agnus-castus L. have a strong antioxidant activity, as show in the results. The best solvent for the extraction of the antioxidant species was ethanol, as expected,
can be used to fight oxidative stress, but there are still many studies to be done, as the plant can have other biological activities.
References
1. Scherer, Rodrigo, Godoy, H. T., Antioxidant activity index (AAI) by the 2,2-diphenyl-1-picrylhydrazyl method, Food Chemistry, 112, 654 658. 2009
2. Saglam,H., Pabuçcuo, A., Antioxidant Activity of Vitex agnus-castus L. Extracts, Phytother. Res., 21, 10591060,2007
3. Sarer, E., Gökbulut, A., Determination of caffeic and chlorogenic acids in the leaves and fruits of Vitex agnus castus, Tur. J. Pharm. Sci. 5 (3), 167 174.2008
4. Sarikurkcu, C., Arisoy, K., Tepe, B., Cakir, A., Abali, G., Mete, E., Studies on the antioxidant activity of essential oil and different solvent extracts of Vitex agnus castus L. fruits from Turkey, Food and Chemical Toxicology 47 2479 2483, 2009
Acknowledgements
To the Unity of Textile & Paper Materials, Chemistry Department of University of Beira Interior for making this work possible.
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Higher Education in Fashion Design - A Course of Research
E. Lima1, M. Calado2, R. Miguel1
1 Unidade de I&D Materiais Têxteis e Papeleiros, Departamento de Ciência e Tecnologia Têxteis, Universidade da Beira Interior, Covilhã, Portugal
2 Faculdade de Arquitectura, Universidade Técnica de Lisboa, Portugal.
Abstract Combining design research and research in design education is considered a key area for design curriculum development (1). Therefore, while teachers in higher education in fashion design, we were motivated to perform work within our doctoral research around models of teaching and learning in fashion design in higher education context. If initially we adopted a research methodology of observing and analyzing models and frameworks, we subsequently developed specific fashion design methodologies on teaching and learning context at Beira Interior University. With a focus on new "tools" for fashion design, we present some reflections and practical preliminary results in fashion design educational context.
Introduction
DESIGN is a well-established area of study, and there are a great number of design courses in many universities and colleges. In our research, in a universe of 185 schools with design education, 40% offers education in fashion design and their expressive has the potential for providing the reason for engaging in Design Research Education (1) Design Research is directed to exploring and understanding the nature of design, its processes and methods. Over the past 20 years textiles and clothing industries have grown substantially, being a powerful business and operating globally. However, these industries and their processes have created both enormous environmental and social impacts (2). Fashion system is considered a set of interrelationships between forms of production highly fragmented and a more or less volatile demanding, aspects that incorporate a conceptual duality: on one hand fashion is strongly dependent of means of production and technologies and on the other hand is a cultural phenomenon (3). Today, eco-efficiency of processes, transparancy and approach among fashion system stakeholders, shifts in focus and cultural values, constitutes key targets for fashion industries can return to a more positive image of themselves and for their activities can contribute for sustainable development.
As Manzini argues, design schools are first and foremost places where the next generation of design experts are educated and have the potential to play a second
important rol of agents of sustainable change. That is, critical and creative actors in the on-going transition towards sustainability (4). Today Design for Sustainability (DfS) is the most challenge approach for all involved in production systems and is everything design can do to facilitate the social learning process towards a sustainable society. That is, promising to sustain social and technological innovations and to re-orientate existing drivers of change towards sustainability. The term "sustainable" means having a more rational approach to problems while considering the long term impact of design, materials and processes affecting people and planet (5). Within these scenarios we focus the current context of sustainable fashion design education’s knowledge, skills and values.
Materials and Methods In the course of education in fashion design at UBI we all been challenged by strategies that could prepare competent designers for most dominant and diverse fashion industries. Committed to prepare “fashion conscious designers” we seek curricula development that enables flexible and resilient skills and awareness, for industry paradigm changes. DfS paradigm goes beyond Design for the Environment, and EcoDesign because it integrates social, economic, environmental and institutional concerns, also creating the opportunity to expression of identity beyond the consumption and standarized mass market (6), usefull principles in adressing problems such as planned obsolescence and waste, lost of product quality, perception of value and cultural diferentiation among others. In sustainable fashion design education field we identify a set of models of teaching / learning benchmarks that reflects fashion design education response. By developing a sustainable fashion design education matrix (Table 1) we have created a panoramic vision about knowledges, areas of expertise and values that are translated into programmatic contents of some international curriculas, with skills and resources that can adress those issues, as well as contribute to the development of new concepts, process and business models.
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Table 1. Sustianable Fashion Design Education Matrix (sample).
In raising awareness for “conscious design” production and consumption, key areas for curricula development research and pratical “tools for design” were identified. Balance between quality of design and quality of production, with the ability to recognize and value the best combination between the socio-cultural values and symbolic expression, improving construction processes with durability and material strength (7); by means of co-creation services, repair and maintenance methods for change consumer behavior and decrease planned obsolescence; addressing principles of slowing the metabolism of people, resources and flows (8) developing emotional bonds between garment and consumer supported by up-cycling or zero waste methodologies (http://www.davidtelfer.co.uk/page2.htm)
In the context of fashion design education approach, we’ve been providing Activity Led-Learning, based on providing stimulating activity that engages and enthuses students, creates challenge, relevance, integration, professional awareness and variety that can be applied in the class-room, in the laboratory, at work, or in any other educational context. Activity Led-Learning, can also be a project, a problem, a scenario, a case study, a enquiry research, a question, or similar, that often cross subject boundaries, within the activities of professional practice does.
Considering emerging scenarios that come from recent Patagónia’s strategies for consumption awarness, Marks and Spencer’s Shwoping project; repair systems from Junky Styling project Wardrobe Surgery, up-cycling from Wornagain and Christopher Raeburn partnerships, are among many others, successful cases of fashion design brands from different markets and approaches, centered on ethics and processes for sustainable production and consumption. By analisys of such cases students can see as proposed by Manzini, how products are becaming
mainly technical and social networks, where people mutually interact (and in turn interact with products and places) in order to get commonly recognized values. We can also see that fashion design activity understood as the creation of clothing for a specific period of time is exponentially magnified and faces new challenges. Based on interactions between people, products and places fashion design can bring new ideias, new behaviours, new economies and new design production processes.
Results and Discussion Preliminary results of design education research at UBI challenge with cases and pedagogies targeted to sustainable design, addressing emerging strategies of “conscious fashion design” activities. New scenarios and new design are two mega trends converging, were products are becoming complex entities (4). From the last century product-oriented approach, design shifts its focus towards a systemic one where the main attention is devoted to interactions. And where the objects to be designed are a complex mix of material and immaterial systems of highly interconnected products, services, places and people (9). Fashion design researches at UBI develop strategies for product longevity, emotional design, zero waste and up-cycling methodologies. With scenarios of product longevity achieved by improving the quality of the item (for example, stitching, colour fastness and durability of fibre), styling with classic lines to minimise susceptibility to fashion, and design that allows for repairs and alteration, lead to reframe systemic thinking and motivate product lifecycle thinking methodologies. Those approaches have been stimulated by contexts of communication for consumer awareness (Figures 1 e 2); Redirect conventional methodologies and
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processes of fashion design (Figure 3) and develop ethnological project-based focusing local economies, textile industries tradition and crafts. Clearly the education of graduates requires closer links with industry to provide and help deliver the real problems referred to and, by implication when this is the case, students engage better with their courses and become highly motivated (10). Internationally, strategic thinking as BAs, I&D centres and new MAs are geared specifically for supporting new business models as well of gradual industries transitions. By means of establishing networks, partnerships and short courses targeted to different fashion system levels (design, marketing and distribution, others) as well as developing partnerships within events, fashion education is engaging in sustainable fashion design markets and green economies.
Figures1 e 2 Experimental work on zero waste methodologies 2nd year Bachelor 2012/13
Figure 3. Experimental work on product longevity 2nd year Bachelor 2012/13
Conclusions Being sustainable development conceived as a main purpose of higher education, contingencies in fashion design education are in the contexts of design culture and methods, production processes, manufacturing, marketing, distribution, and such should sensitize and convey skills in their areas of concerted training strategies, that allow a practical application of environmental, social and economic upgraded values, stimulating development, equity, diversity and participation (United Nations, 1992 Talloires Declaration 1992, HEASC, 2005). Today, eco-efficiency of processes, transparancy and approach among fashion system stakeholders, shifts in focus and cultural values, constitutes key targets for fashion industries can return to a more positive image of themselves and for their activities can contribute for sustainable development. Fashion design education at UBI is a path of research by engaging in practical tools for product longevity, emotional design’s own cultural perspectives, zero waste and up-cycling methodologies. Those strategies enable students to develop their fashion design skills without failing an ethical and green philosophy or jeopardizing creativity, innovation and social awareness. These resources can contribute to generate new design and conceptual development, transitional industry processes and new business models. References 1. Tovey, M. (2011). Researching Design Education. CUMULUS / DRS SIG on Design Pedagogy 1st International Symposium for Design Education Researchers Paris Chamber of Commerce and Industry, Paris, France 18–19 May 2011. 2. Pasricha, A., Kadolph, S. (2009) “Millennial generation and fashion education: a discussion on agents of change” International Journal of Fashion Design, Technology and Education, Disponível em http://dx.doi.org/10.1080/17543260903390183. Acesso Jan 2010. 3. Fine & Leopold (1993) The Worl of Consumption. Routlege, 1993 4. Manzini E. (2011). Design schools as agents of (sustainable) change: A Design Labs Network for an Open Design Program. CUMULUS / DRS SIG on Design Pedagogy 1st International Symposium for Design Education Researchers Paris Chamber of Commerce and Industry, Paris, France 18–19 May 2011. 5. Benson, Eric (2009) Sustainable Design Education Rethought: The Case for Eco-modernism in Design Principles & Practices: an International Journal, University of the Arts London, UK.Volume 3, Number 6.
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6. Spangenberg, J.H.Fuad-Lucke, A., Blincoe, K. (2010) Design for Sustainability (DfS): the interface of sustainable production and consumption, published in Journal of Cleaner Production 18 (2010) 1485e1493. 7. Fletcher, K. 2010. "Slow Fashion: An Invitation for Systems Change." Fashion Practice: The Journal of Design & Creative Process 2 (2): 259-266. 8. Carolyn F. Strauss, Fuad-Lucke, A., (2008) The Slow Design Principles A new interrogative and reflexive tool for design research and practice in Carla Cipolla, e Piero Paulo Peruccio (Ed.) Changing the Change. Design, Visions Proposals and Tools. Torino: Umberto Allemandi & C.. 9. Manzini, Collina, Evans, 2004; Halen, Vezzoli, Wimmer, 2005; Thackara 2005; Green, 2009; Pauli, 2010 in Manzini Enzio (2011). Design schools as agents of (sustainable) change: A Design Labs Network for an Open Design Program. CUMULUS / DRS SIG on Design Pedagogy 1st International Symposium for Design Education Researchers Paris Chamber of Commerce and Industry, Paris, France 18–19 May 2011. 10. White P., Dunn I., Farmer R. and Lawson D. (2009) Meeting the needs of Industry through Activity Led Learning. 2nd International Research Symposium on PBL, Dec 2009, Victoria University, Melbourne, December 2009.
Acknowledgements
The guiding professors Profª Maria Calado and Prof. Rui Miguel, by their openness to our ideias and multidimension methodologies. Profª Rita Salvado, by encouraging and supporting curriculum development on sustainable fashion design. Profª Madalena Pereira, by literature sujestions. A special thanks to fashion design students at UBI, their enthusiasm with which respond to the proposed approaches.
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Natural textile dyes: Biotechnology for a sustainable development in textiles
G. C. Santos *, C. Carvalho * * CIAUD – Centro de Investigação em Arquitectura, Urbanismo e Design
Faculdade de Arquitectura – Universidade Técnica de Lisboa Rua Sá Nogueira, Pólo UniversitárioAlto da Ajuda, 1349-055 Lisboa
[email protected] / [email protected]
Abstract
In these last decades, environmental problems have become increasingly critical and frequent, mainly due to rampant population growth and increased industrial activity. The contamination of water is undoubtedly one of the major problems of modern society. Within this context, the textile sector deserves special attention. It is crucial to see how to circumvent the main problem that the textile industry is currently facing - the use of synthetic dyes. The revival of natural dyes, in addiction to the new cutting edge technologies, allow existing trigger actions that result in reduced environmental impact or in new strategies for sustainable development. That the use of natural dyes give yourself effectively is a fundamental understanding of this issue and the search for biodiversity dyes capable of providing colored compounds, many never before explored. But not only the natural colors can be an alternative to synthetic dyes currently available commercial and highly sophisticated technologies to optimize their application - providing an endless path of solutions for the textile industry and a positive scenario in solving their problems and needs .
1. Introduction
As professionals and consumers, analyzing and acting for/in a society, rational and/or intuitively, one has to assume a critical and responsive position to the environmental attitudes within it.
To dye or to print with natural dyes has always been fundamental in art and in the cultural identity of mankind. The dyestuff is a colored substance used to assign permanent color to other substances. Its most important use is to dye fiber, yarn and woven textiles. The dyes can be divided into two groups: natural and synthetic.
The synthetic dyes arise from the nineteenth century (Garfield, 2002) and today can be found more than 2000 different types of synthetic dyes, only in the textile industry (Zollinger, 1991). Its marketing has withdrawn almost entirely the natural pigments from the market, however, the use of synthetic dyes and its discharges textile effluents causes serious ecological problems and present toxicological risks for the consumers (Vandevivere, 1998), becoming one of most serious problems of the textile industry.
This problem led to the revival of natural dyes and the pursuit of knowledge for biodiversity (DBT, 2005) capable of providing colored compounds which by their
biodegradable nature, have a high affinity with the environment (Bhuyan et al., 2004) also presenting a large potential dyestuff.
This study intends to instigate eventual investigations which results in a reduced environmental impact or in new sustainable development strategies through greater understanding of the universe of natural colored compounds, processes and/or techniques.
Biotechnology - classical or modern, allied to the ancestral knowledge, represents a fundamental role for the real scope of sustainable development (Bryce et al., 2004), ensuring, on the other side, the industrial viability, presenting itself as an aid in finding solutions to current problems and their unavoidable nature. 2. Problem, Hypothesis and Method
It is necessary a deep understanding of the variety of colorants in order to circumvent the main problem of the textile industry - the use of synthetic dyes, harmful due to their toxic effects on consumer (Clarke et al., 1995) and environment (Cooper, 1993). The incentive to research the most diverse and potential sources of natural dyes (types, dyeing processes and technologies involved) is essential and crucial in the development of new dyes (Bhuyan et al., 2004) capable of meeting the needs of the manufacturer and consumer as well as the protection of humans and the environment.
Sophisticated technologies such as Biotechnology among others, provide the optimum application of natural dyes compounds and their quantity allowing the industrial viability and cost and energy reduction. They also allow to acquire a variety of colored compounds that lack the drawbacks of the ones commercialized today. Biological resources provide protection for consumers and less environmental impact (Kozlowski, et al., 2006).
Currently, there are techniques that allow the manipulation and transformation of the characteristics of living things. Through genetic engineering, the gene that contains the information for the production of a substance of interest can be transferred to another body (Ratledge and Kristiansen, 2001), which will produce large quantities of the same substance even though he never produced it before. At present, the cotton fiber that holds a natural blue color (Chen et al., 2007), through modern biotechnology, allows the elimination of toxic synthetic dyes application in the process of finishing the fabric, reducing the incidence of damage to the environment during the dyeing process. This is an appropriate
105
procedure in the manufacture of green and organic clothes. The use of dyestuff extracted from plants, animals or microorganisms (Lu et al., 2009) is a biotechnological practice used for thousands of years in the dyeing process, which can also be optimized based on biotechnology modern, if we wish so (Vankar et al., 2008).
The use of biotechnology in the textile field results in processes that produce less waste to the environment and that use less energy and water, becoming one of the most promising cutting-edge approaches in preventing and reducing pollution, conserving resources and reducing
costs. It also allows natural dyes to be used and viable on an large industrial scale.
The study methodology consists in research and analysis of archaeological, ethnological and historical documents relevant on the identification of natural colored compounds of the main colors, providing and covering a variety of the different civilizations. The study demonstrates the survey and identification of natural dyes and processing techniques for their application, and by identifying we did not get restricted to the technical and chemical meaning but we also cover information on its provenance, applications and technologies involved.
3. Results
Dye source Part used Colorant substance
Shades and mordants
Fibers Geographic location
Rubia tinctorum Roots
Alizarin
Purpurin
Pseudopurpurin
(anthraquinones)
Bright Red (aluminium salts)
Bluish Red (calcium salts)
Dark Purple (iron salts)
Orange/Yellow/Ochre (tin salts)
Brown ( aluminium+iron salts )
Protein fibers and cellulose
Europe, Asia, Middle East
Acridocarpus Excelsus
Wood (bark) Red (without mordant)
Cellulose Madagascar
Caesalpina echinata Wood (bark) Brazilin
Brasileína
Orange (tin + alum)
Brown (chromium + copper)
Protein fibers and cellulose
America., Asia (India,
(Sry-lanka, Malasia)
Bixa orellana Seeds Bixin
Isobixin
Red (without mordant)
Ochre/Yellow/Orange (without mordant)
Protein fibers and cellulose
America, Asia (Philippines), Africa
Baphia nitida Leaves
Wood
Red (without mordant)
Brown (without mordant)
Protein fibers and cellulose
Africa
(Senegal,
(Gabon, Liberia, Sierra Leon)
Reseda luteola Seeds
Upper branches
Luteolin
(flavonoids)
Bright Yellow (without mordant)
Orange (aluminium salts + tin)
Green (iron salts)
Brown (chronium)
Protein fibers
West Asian, Europe, North Africa
Crocus sativa Stigmata of the
flower Crocetin
Crocin
Yellow/Orange (without mordant)
Protein fibers and cellulose
Europe, Asia
Carthamus tintorius Flower petals Cartamin
Yellow (alumen)
Orange (without mordant)
Brown (copper)
Protein fibers
Red/Pink (without mordant)
Cellulose
Asia, South Europe and North Africa
106
(Cont.)
Dye source Part used
Colorant substance
Shades and mordants
Fibers Geographic location
Chlorophora tinctoria
Wood Morin
Yellow (without mordant)
Orange (alumen)
Dark red (chromium)
Brown (copper)
Protein fibers and cellulose
America, South Europe
Alectra sessiliflora Leaves
Roots
Yellow (without mordant)
Protein fibers and cellulose Africa, Asia
Isatis tinctorum
Indigoferae Leaves Indigo
Blue (alumen)
Grey (copper or chromium)
Protein fibers
Europe, China, Asia, America (middle and south), Africa subsaariana (tropical and subtropical
regions)
Juglans regia Wood (bark)
Juglone
(naphthoquinone)
Brown (without mordant)
Black (iron salts)
Protein fibers and cellulose
East, South Europe
Acacia nilotica Green beans
Khaki/Brown
Grey/Black (iron salts)
Cellulose
Asia (India, Myanmar, Sry-lanka), Africa (Senegal Egypt, Mozambique and South África), Cape Verde, Jamaica, Nepal, Indonesia, Vietnam,
Australia
Anogeissus leiocarpa
Leaves
Roots
Gallic Acid
and Ellagic
(Flavonoids)
Yellow/Ocher/Red (without mordant)
Black (iron salts)
Cellulose
Africa (Senegal, Ethiopia, Congo)
Barringtonia racemosa
Wood (bark)
Roots
Brown Red (without mordant)
Grey/Black (iron salts)
Protein fibers and cellulose
Africa (Somalia and South Africa), Tropical Asia, Madagascar, Indic Islands, Micronesia, Polynesia,
North Australia
Bruguiera gymnorhiza
Wood (bark)
Orange/Brown Red (without mordant)
Purple/Grey/Black (iron salts)
Protein fibers and cellulose
Africa (Middle and South), Madagascar, Indic Islands, Tropical Asia, North Australia,
Micronesia e Polynesia
Haemotoxylon campechianum
Wood Hematoxylin
Purple/Black/Blue (without mordant)
Protein fibers
Blue/Black (without mordant)
Cellulose
Middle America nad Europe
Roccela tinctoria The
whole lichen
Orcein
Red (tin salts)
Violet/Purple (alumen)
Cellulose
Red/Brown/Blue/Purple (without mordant)
Protein fibers
Atlantic Coast, Europe
107
(Cont.)
4. Discussion
The recent changes in legislation relating to certain synthetic and toxic dyes and the increasing preference for natural products by consumers, led to the awakening interest in natural colored compounds, mostly derived from plants. Its use is still very little (only a small niche market uses these products) leading the few natural dyes to display high prices. Determined to bring this type of dyestuff further, to an industrial scale, it is required some superior conditions for the production of plants and their growth as well as methodologies and technologies adapted to the diverse requirements.
Address the environmental impact, the natural dyes present many fewer problems compared to synthetic dyes.
Although many do not attach importance to them because of their instability and industrial alleged impracticality, this study shows that its use has many advantages, especially in an era in which modern biotechnology (or other innovative technological processes) can be decisive, given its ability, efficiency and various applications (Vankar, et al, 2008). The line of natural dyes Ethno Botany Colours was created from the union of the Etno knowledge of Brazil, in search of natural dyes, Centroflora Group, the production of plant extracts, and Cognis Brazil, enabling innovative applications for this new line extracts dyes. Besides the development of safe natural dyes, industrial applications with low environmental impact, this cooperation is aimed at creating alternatives for sale to small farmers and rural
Dye source Part used Colorant substance
Shades and mordants
Fibers Geographic location
Arnebia hispidissima Roots
Violeta/Purple (without mordant)
Protein fibers and cellulose
North Tropical Africa (Nigeria, Camerron, Sudan), Egypt and North
India
Kermococcus vermilis Insect female in
pregnancy Quermesic acid
Red (without mordant)
Protein fibers and cellulose
Europe, East, Asia
Dactylopius coccus Insect female in
pregnancy Carminic acid
Red/Violet/Pink (without mordant)
Protein fibers and cellulose
Middle America, South Spain and Canarias Islands)
Murex Hypobranchial glands
of the snail 6.6’ – dibromo-
indigo
Pink (without mordant)
Violet/Purple (without mordant)
Red (without mordant)
Protein fibers and cellulose
Europe, East, Middle and South America
Streptomyces coelicolor
Microorganisms Blue
Chomobacterium violaceum
Janthinobacterium lividum
Microorganisms Purple
Monascus sp
Phaffia rhodozyma
Micrococcus roseus
Brevibacterium linens
Bradyrhizobium sp
Xanthomonas campestris
Microorganisms Yellow and Red
108
communities, forming a network of sustainable raw materials. Combining technology and environmental awareness, the line Ethno Botany Colours contributes to the construction of a new concept on the use of industrial dyes, creating an alternative for the beginning of a new position responsible drinking in which the waste and degradation result in the sustainable use of biodiversity and enhance quality of life. In the textile industry, these natural dyes are used in the dyeing of yarn, fabric and mesh, combining fashion and ecology (Centroflora Group, 2004). Ethno Botany Colours line is the result of the development of dyes extracted from native species of flora and species adapted to the national territory, which have historical importance in the economic, social and cultural scene.
5. Conclusions
The growing concern with environmental quality, the fact that some synthetic dyes are obtained from non-renewable sources and toxicity of these dyes have led to a growing interest in the textile industry by the reintroduction of natural dyes.
As can be seen, the natural dyes, whose characteristics reveal themselves biodegradable without serious consequences for consumers and the environment, may contain solutions that can effectively overcome one of the serious problems industrial textiles, directing it to a new strategy sustainable development. Its use in the dyeing processes shows that the vast majority is effective in terms of soundness, ensuring moreover different colors and shades, fulfilling the needs of manufacturers and consumer requirements.
Are very important, therefore, very knowledgeable about the existing biodiversity and a greater understanding about the behavior and potential of the various dye species (animals, plants, microorganisms), are already listed, other investigating. It is also necessary, information on new technologies and innovation of all existing materials at present for these dyes can be applied without any restrictions.
In this study, it is understood that many natural dyes are presented somewhat unstable, yet costly technologies involved and which are characterized by lengthy procedures and a higher degree of difficulty in obtaining them, suggesting that its application to the industrial level has not been given offers competitions economic / industrial force. The colossal amount of coloring matter necessary to perform the dyeing process also presents itself as a barrier to the use of these compounds by industry. However, through recent and sophisticated tools of modern biotechnology, among others, the possibility now exists for the use of natural dyes in a way never before possible.
Knowledge of the multitude of natural resources (obtained through the history of dyeing and techniques from ancient times, as well as the wisdom of certain indigenous peoples on these) can be refined and explored based on innovative technologies available so that the use natural dyes is feasible on an industrial scale.
After new dyeing techniques like Sonic dye, a technique that allows an extreme fixation of the dye in the fiber improving color fastness, we can establish a trust in the natural dyes are often accused of not possessing the necessary stability to industrial demands.
Through genetic engineering, a gene that contains information for the production of a substance of interest can now be transferred to another body, which will then produce large quantities of the same substance even though he never produced it before. Cotton blue (genetically altered) presented in this study is a good example of one of the most promising approaches to the forefront in preventing and reducing pollution, conserving resources and reducing costs. By eliminating the various stages of dyeing (affecting the environment and include spending at the level of resources, ie water and energy) is established to bridge that enables the sustainable development of textile industry.
Thus, the sustainable exploitation of biodiversity exists for the use of natural dyes becomes an alternative for the textile industry mitigates the negative effects on the environment and for consumers. With the knowledge and understanding of the various plant and animal species can be obtained separate textile dyes that, in addition to prove effective in terms of dye (solid) offer an infinite range of colors complying with the requirements of consumers.
Biotechnology currently allows for such improvements with regard to dyeing which allows, as it turned out, the reduction of time in projects for improvement and consequent cost reduction. It translates into lower energy expenditure, water, and reduction or elimination of textile effluents. Provides natural dyes industrial viability revealing itself economically advantageous.
All natural resources (dye plants and animals) in this study represent a wide genetic stock which may be exploited, either by careful selection, whether the results from crosses between species previously selected.
In this issue the main issue is how to make these technologies available, including the main producing countries remain the poorest and underdeveloped countries. The lack of information also means that producers of dyes are not familiar, preventing them from taking a proactive stance in this regard. It is important to see how appealing it may make use of these technologies, and added that the initial investment which is subsequently behave negligible, so that companies interested and increasingly engage in these solutions.
109
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Bhuyan R, Saikia C N, Das KK (2004) Extraction and identification of colour components from the bark of Mimusops elengi and Terminalia arjuna and evaluation of their dyeing characteristics on wool. Indian Journal of Fibre & Textile Research, 29, 470-476
Bryce, CFA, Balasubramanian, D. (2004). Concepts in biotechnology. (3ª ed.), Orient Blackswan. Centroflora. Consultado em Dezembro 2008: www.centroflora.com.br
Chen, J, Wang, Q, Hua, Z & Du, G (2007). Research and application of biotechnology in textile industries in China. Enzyme and Microbial Technology 40, 1651-1655
Clarke, EA e Anliker, R (1980): Handbook of Environmental Chemistry Chemical Safety. O. Hutzinger (Ed.), Vol.3 , Springer Berlin
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Department of biotechnology, Ministry of Science and Technology (2005). Prospecting of bioresources for natural dyes. Consultado em 6Junho de 2009: http://dbtindia.nic.in/proposals/natural_dyes.html
Dirty Laundry (2011). Greenpeace Research Report, http://www.greenpeace.org/international/en/publications/reports/Dirty-Laundry/ (consultado em Outubro de 2011)
Garfield, S (2002). Mauve: how a man invented a color that change the world. Faber & Faber.
Kozlowski, R, Zaikov, G E & Pudel, F (2006). Renewable resources and plant biotechnology. Nova Publishers
Lu, Y, Wang, L, Xue, Y, Zhang, C, Xing, XH, Lou, K, Zhang, Z, Li, Y, Zhang, G, Bi, J & Su, Z (2009). Production of violet pigment by a newly isolated psychrotrophic bacterium from a glacier in Xinjiang, China. Biochemical engineering Journal 43, 135-141
Ratledge, C & Kristiansen, B (2001). Basic biotechnology. (2ª ed.), Cambridge University Press
Santos, G C, (2010). Corantes têxteis naturais: A biotecnologia da antiguidade até ao século XXI. Tese de Mestrado, Faculdade de Arquitectura – Universidade Técnica de Lisboa
Vandevivere, PC, Bianchi, R, Verstraete, W (1998). Treatment and reuse of wastewater from the textile wet-processing industry: Emerging Technologies, Journal Chemistry Technology Biotechnology, 72 (4): 289-302
Vankar, PS, Shanker, R, Dixit, S, Mahanta, D & Tiwari, SC (2008). Sonicator dyeing of modified cotton, wool and silk with Mahonia napaulensis DC. And identification of the colorant in Mahonia. Industrial crops and products 27, 371-379.
Zollinger, H. (1991). Color Chemistry, Syntheses, Properties and Application of Organic Dyes and Pigments. 2º edition, VCH.
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Cold-plasma assisted grafting of cellulose fibers by acrylic monomers C. Gaiolas 1, M.E. Amaral1, A.P. Costa 1, M.J. Santos Silva 1 and M.N. Belgacem 2
1University of Beira Interior, Research Unit of Textile and Paper Materials, 6200-001 Covilhã, Portugal 2Grenoble INP-Pagora, Paper, print media and biomaterials, LPG2, Grenoble, France
Abstract Additive-free handsheet paper samples were activated by cold-plasma in the presence of acrylic acid (AAc), acrylamide (AAm), methyl acrylate (MAc) and methyl methacrylate (MMa). The characterisation of the modified substrates showed that there grafting has occurred efficiently, as established by weight gain and FTIR spectroscopy. The contact angle measurement were carried out, as a function of pH and showed that the deposition of a drop of water at the surface of the tested samples formed 55º for unmodified substrate to 87°, for MMa treated papers, respectively, indicating that the surface has became totally hydrophobic. ATR-FTIR spectroscopy was used to check the grafting efficiency.
Introduction Lignocellulosics and cellulose are the main raw material for paper and textile commodity products. They are used in high amounts and in different applications and are known to be polar and hydrophilic macromolecules. These products could be used in some applications in which the presence of water is undesirable, whereas in some others they are mainly used for their affinity with water (when looking for super absorbancy). In fact, when cellulose fibres are used in composite materials, the presence of water induces a negative effect on these articles (reduction of mechanical properties, high energy consumption when drying, etc.). To limit such drawbacks, special treatments aiming at reducing the hydrophilic character of cellulose materials may be required. Instead, for other applications, such as super-absorbent materials, even if cellulose fibres absorb intrinsically high amount of water, they should be submitted to a specific treatment in order to boost their absorption and retention of liquid water [1-3]. Cellulose modification (surface and bulk) was carried out for a long time using solvent-based processes. The need of developing eco-friendly modification strategies require several criteria, among which solvent-free and/or water based and low energy consuming techniques of preparation. In this context, we have developed new approach of surface modification of lignocellulosics using cold-plasma technique. In fact, plasma discharge meets at least a part of such requirements. The treatment can be carried out under different controlled atmospheres, which open the way to the use of a large array of chemicals, thus allowing designing materials with various properties [4,5]. We have used cold-plasma to graft cellulose with terpenes, silane coupling agents, as well as styrene and
other halogeno-substituted derivatives [6-8]. For such a purpose, we used additive-free hand sheet paper samples and submitted them to cold-plasma in the presence of limonene, myrcene, vinyl-trialkoxysilane, methacrylopropyltrialkoxysilane, styrene, alpha-methyl styrene, as well as fluoro-, bromo- and chloro-substituted styrene or alpha-methyl styrene. These studies showed that cellulose can be chemically linked with these double-bonds bearing molecules. In all cases, contact angle measurement and X-ray Photoelectron Spectroscopy (XPS) have showed that the grafting as indeed occurred. Moreover, cold-plasma can be applied in the treatment of recycled paper has the advantage of contributing to the reduction of energy consumption in disintegration process [9]. To the best of our knowledge, in addition to our own studies, only two papers [10,11] have been reported the effect of plasma treatment of lignocellulosic fibers, as a tool to graft either acrylic monomers (methacrylic acid [10] and acrylamide [11]). This paper describes the use of acrylic monomers (acrylic acid, acrylamide, methyl acrylate and methyl methacrylate) with a solvent-free activation process based on plasma discharge. The efficiency of the grafting was evaluated as a function of treatment time and ground pressure, and the treated sheets were characterized using ATR-FTIR spectroscopy and contact angle measurements.
Materials and Methods Additives-free laboratory hand sheet papers were prepared from bleached kraft pulps of Eucalyptus, according to standard procedure ISO 5269-1:2005. Their basis weight was 40 g/m2. The prepared paper samples were soxhlet extracted with methylene chloride, for 6 h, prior to cold-plasma treatment, as established in our previous work [6]. Four coupling agents were used, namely acrylic acid (AAc), acrylamide (AAm), methyl acrylate (MAc) and methyl methacrylate (MMa). These chemicals were commercial products from Sigma-Aldrich Inc. The other chemicals and solvents used were also commercial products with highest purity available. All the chemicals, solvents and grafting agents were used as received.
OHO NH2O O O AAc AAm MAc MMa
Figure 1. Chemical structures of the acrylic and methacrylic monomers used in this work.
111
EUROPLASMA apparatus equipped with a microcontroller, a vacuum system and a 2.45 GHz microwave generator was used to carry out the initiation of the four monomers in the presence of paper films, under a treatment power of 200 W and a ground pressure varying from 200 to 700 mT. The paper was submitted to plasma discharge for 30, 60, 90 and 180 s. Three different processing conditions were tested. The first one was based on the activation of the substrate and the immersion of activated paper into the monomeric liquid. This approach will be named: “activation-immersion”. The second approach called upon the impregnation of the substrate to be treated by the chosen monomer and then the exposure of the impregnated sheet to plasma discharge (“impregnation treatments”), whereas the third method was a more complete route. It was based on impregnation of the paper sample followed by its plasma activation and then again its immersion into the liquid monomer. We have called this route as: “impregnation-activation-immersion”. The treated paper samples were kept 24 h under atmospheric conditions before being submitted to a systematic Soxhlet extraction with methylene chloride for 6 h, in order to remove the physically adsorbed unbounded polymer macromolecules. ATR-FTIR spectroscopy was used to check the grafting efficiency. The spectra were recorded on a, using a Perkin-Elmer SP100 spectrometer. For each sample, the Diamond crystal of an attenuate total reflectance (ATR) apparatus was used. The torque applied was kept constant to ensure the same pressure on each sample. All spectra were recorded between 4000 and 600 cm-1, with a resolution of 4 cm-1 and using 16 scans. A minimum of 2 spectra were obtained on different area of the paper for each sample. Contact angle (CA) measurements were used to characterize the pristine and treated paper samples as describe previously [6-8].
Results and Discussion We could not applied the optimal plasma grafting conditions established in our previous work and dealing with other coupling agents, because we have shown that the optimal plasma activation conditions differ from a coupling agent to another [6-8]. Even though, a preliminary study showed that the energy applied to treat paper should be fixed at 200 W. Then, a set of experiments was carried out using different operating conditions with the main objective of establishing the optimal ground pressures and time. These two parameters were varied for the ground pressure between 200 and 700 mT. For each pressure, the time of treatment was varied, in order to optimize the grafting efficiency (30, 60, 90 and 180 s).
From this set of experiments, the optimal plasma conditions for acrylic monomers are a power treatment of 200 W, a ground pressure of 700 mT and a treatment time of 60-90 s. The plasma-treated paper samples were
characterized by weight gain and contact angle measurements, before and after soxhlet extraction, as summarized in Table 1. The weight gain of the samples after grafting and soxhlet extraction shows that the grafting has indeed occurred and that the acrylic acid, in its salt form (sodium acrylate formed when treating the AAc with hydroxyl sodium at a pH value of 8), is the most effective monomer to graft cellulose. This result could be associated to the fact that sodium salt derivative is more reactive that its acid homologue, because of the enhanced electron density of the acrylic moiety induced by the conversion of COOH to COO-Na+. Moreover, sodium acrylate yielded a monomer which could be co-polymerized with cellulose, since only the grafting has occurred. In fact the amount of the homopolymer was negligible (No difference of the weight gain before and after extraction). Acrylamide was found to form a big amount of homopolymer, as indicates the drastic decrease of the weight gain, after solvent extraction of the modified substrates aiming to remove unbounded grafts. The contact angle which a drop of water formed at the surface of the the untreated samples is about 55°. After treatment, the paper surface formed, with a drop of water; an angle to 30°, confirming the occurrence of the grafting.
Figure 2. ATR-FTIR spectra of plasma treated paper in the presence of acrylic monomers.
Figure 2 shows the ATR-FTIR spectra of untreated, AAm- and AAc-treated samples. For the last one, the treatment was carried out at pH = 8, as mentioned before. These spectra confirm those found in weight gain and contact angle measurements, as emphasized by the appearance of the peaks (indicated by arrows in Figure 2) corresponding to the carbonyl groups of acrylic monomers (1668-1680 cm-1).
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
5001000150020002500300035004000
Wavenumbers (1/cm)
Abs
orba
nce
Untreated sample
AAm-treated sample
AAc-treated sample (pH 8)
112
Table 1. Weight gain and contact angle measurements, before and after soxhlet extraction.
Sample Time (s)
Weight gain (%) Contact angle
Before extraction After extraction Before extraction After extraction
Untreated - - - 55
AAm 30 77.5 0.7 35 27
AAm 60 79.6 1.5 26 26
AAm 90 67.1 5.6 23 33
AAm 180 69.8 - 27 37
AAc (pH = 8) 90 29.7 29.0 31 45
AAc (pH = 1) 90 15.3 1.5 60 73
MAc 90 0,0 0,0 84 86
MMa 90 1,4 1,3 88 87
Conclusions This paper shows clearly that cellulose macromolecules can be grafted successfully by acrylic-based monomers and constitutes an interesting route to modify fibrous-mat films, for both purposes: hydrophobisation and super absorbency, depending on the monomer used. Moreover, for the second family, it was observed that the grafted substrates were pH sensitive. The polymerization of acrylic acid in its sodium salt form yielded very efficient grafting, since it gave high weight gain. This gain was impossible to remove by extraction, indicating that an efficient grating has occurred and that the amount of the formed homopolymer is negligible. An additional advantage associated with this technique is that plasma can be applied as a continuous process, which is fits perfectly with the common production route in papermaking and textile industries. References 1. M. N. Belagacem and A. Gandini (Editors),
Monomers, Polymers and Composites from , ELSEVIER, Amsterdam,
p.560, 2008 2. R. P. Wool and X.S. Sun (Editors), -Based
ELSEVIER, Amsterdam, p.620, 2005
3. C. V. Stevens and R. G. Verhé (Editors), bioresources: Scope and Modification for non-food
JOHN WILEY & SONS, LTD, Chichester, p.310, 2004
4. M. N. Belgacem and A. Gandini, Comp. Interface, 12, p.75, 2005
5. N. Inagaki, , Technomic Publishing Co, Basle,
Switzerland, p.276, 1996
6. C. Gaiolas, A. P. Costa, M. Nunes, M. J. Santos Silva, M. N. Belgacem, Plasma Processing and Polymers, 5, p.452, 2008
7. C. Gaiolas, M. N. Belgacem, L. Silva, W. Thielemans, A. P. Costa, M. Nunes, M. J. Santos Silva, Journal of Colloid and Interface Science, 330, p.298, 2009
8. C. Gaiolas, A. P. Costa, M. J. Santos Silva, M. N. Belgacem,. 6th International Conference on Times of Polymers (TOP) and Composites, AIP Conf. Proc.; Volume: 1459, p.286, 2012; doi: 10.1063/1.4738471
9. Gaiolas C, Costa AP, Santos Silva M, Thielemans W, Amaral M.E, Industrial Crops Products, 43(1), p.114, 2013
10. R. Mahlberg, H. E. M. Niemi, F. Denes, R. M. Rowell, Intern. J. Adhesion Adhesives, 18, p.283, 1998
11. N. Ostenson, H. Jarund, G. Toriz, P. Gatenholm, Cellulose, 13, p.157, 2006
Acknowledgements
The authors thank FCT (Fundação para a Ciência e Tecnologia) for the awarding of post-doc grant to Carla Gaiolas, within the Community Support Framework III.
Paper presented at international conference:
6th International Conference on Times of Polymers (TOP) and Composites, AIP Conf. Proc., © 2012 American Institute of Physics, 10-14 June 2012, Ischia, Italy.
Available with:
doi: 10.1063/1.4738475
113
POSTERS
115
New N-alkyl-2-alkylsulfanylacetanilide atropisomers: synthesis and VT NMR study
S. S. Almeida1, R. E. F. Boto1, S. S. Ramos2, P. Almeida1 1 CICS, Health Sciences Research Center, University of Beira Interior, 6201-001 Covilhã, Portugal; 2UMTP and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã,
Portugal
Abstract NMR spectra of N-alkyl-acetanilides derivatives bearing a single alkylsulfanyl group in thde ortho position indicate that they exist as two possible conformers, due to the restricted rotation about the Ar(C)-N bond. The corresponding rotation barriers were determined.
Introduction The hydrolysis of some quaternary ammonium salts 1 which, under residual water and basic conditions, suffered heterocyclic ring opening to yield the corresponding N-
alkyl-2-alkylsulfanylacetanilides (X = S) or 2-alkoxy-N-alkylacetanilides (X = O) 3 as atropisomers, as already been described (scheme).1 This reaction allowed the selective introduction of different R1 and R2 substituents, which is not easily carried out starting from ortho-hydroxy- or ortho-thiohydroxyanilines. As atropisomers, the coalescence temperature (Tc, K) and free energy of activation (G‡, kcal/mol) of, for example, N-alkyl-2-alkylsulfanylacetanilides 3 (X = S) can be estimated by using Variable Temperature NMR method (VT-NMR).2
X = S or O; R1 = Ethyl, Propyl or Hexyl; R2 = Ethyl, Propyl or Hexyl a) R1I, CH3CN, reflux; b) NEt3, 96% ethanol, reflux; c) ehanol, NaOH, R2I, reflux; d) LiAlH4:AlCl3, ether
Scheme – Synthetic procedure
Materials and Methods Reactions were monitored by thin layer chromatography (TLC) eluted with CH2Cl2/MeOH (9:1). Column chromatography was performed on silica gel Fluka-Kielselgel 60Å, 63-200μm). The structures of the isolated products 3 and 4 were characterized by IR, 1H and 13C NMR spectroscopy, and electrospray ionization mass spectrometry (ESI-TOF). The IR spectrum of compounds 3 showed absorption at 1656-1660 cm-1 indicating the presence of an amide, whereas the IR spectrum of compounds 4 lack this absorption, as expected. In all cases, the mass spectra displayed [M+H]+ peaks at appropriate m/z values.
NMR spectra were recorded at 400 MHz for 1H and at 100 MHz for 13C, referenced to the residual protonated solvent. The temperature was calibrated before the VT experiments by means of a thermocouple which has an uncertainty not exceeding ± 1 °C.
General procedure for the hydrolysis of 3-alkyl-2-methylbenzothiazol-3-ium iodides 1 to the corresponding N-(2-(alkylthio)phenyl)-N-alkylacetamides 3: A solution of 3-alkyl-2-methylbenzothiazolium iodide 1 (1.0 mmol) and triethylamine (1.1 mmol) in 96% ethanol (100 mL)
was heated under reflux. The reaction was complete in 30 to 60 min. The solvent was removed under reduced pressure and the crude reaction product was dissolved in ethanol. Following the addition of sodium hydroxide (1.2 mmol with reference to salt 1) and the appropriate alkyl iodide (1.0 mmol), the reaction mixture was heated under reflux for more 2 to 5 hr. After completion of the reaction, the solvent was removed under reduced pressure, the crude residue was dissolved in CH2Cl2 and extracted sequentially with 10% aqueous HCl and 10% aqueous NaOH. The organic layer was then washed with water, dried over anhydrous Na2SO4 and evaporated to dryness. The resulting pinky-red oil was purified by column chromatography using dichloromethane-methanol (from 9.5: 0.5 to 9:1) as eluent. The pure brown yellowish products are obtained in moderate to good yields.
Results and Discussion It was verified that acetanilides 3 are present as a mixture of atropisomers, by the observation of the non-equivalence geminal NCH2 protons in the 1H NMR spectra, despite no individual characterization of each atropisomer could be achieved by direct NMR analysis.
X
N
a) d)X
N
R1I
b)c)
X
N
OH
R1
X
N
R2
R1
COCH3
X
N
R2
R1
1 2 3 4
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However, VT NMR experiments so performed by raising the temperature of the DMSO-d6 solution of 3, witnessed, as expected, the broadening and coalescence and the of the methylene signals, yielding one single signal, resulting from the rapid interconversion betweeen the two conformers, allow us to estimated the G‡ of a serial of new N-alkyl-2-alkylsulfanylacetanilide 3.
The G‡ estimation (Table 2) was performed by using the Eyring equation and the rate constant (Kc, s-1, Eqs. 1-3)2
Kc = πΔν/2 = 2.22Δν (1)
ΔGǂ = 2.303 R Tc (10.319 + log Tc/Kc) (2)
ΔGǂ = 4.569 x 10-3 Tc (10.319 + log Tc/Kc) (3)
Tc is the coalescence temperature, defined as the lowest temperature at which the two rotamers merge. The rate constant Kc (s-1) is calculated from Δν which is easily accessed from VT NMR spectra analysis (Table 1).
Table 1 – VT NMR of some N-alkyl-2-alkylsulfanylacetanilides 3
Compd. R1 R2 δ1 (ppm) δ1 (ppm) Δν Kc (s-1)
3a Et Et 3.944 3.084 344.11 763.92 3b Pr Et 3.881 2.961 368.12 817.23 3c Et Pr 3.953 3.091 344.91 765.70
Δν = (δ1 – δ2) x 400.13 Surprisingly, the presence of an alkylsulfanyl group in the ortho position of acetanilides 3 reveals to have a dramatically effect on the restriction around Ar-N bond rotation, not expected regarding the bulky, but not so extremely bulky nature of the alkylsulfanyl group. As consequence, the coalescence temperatures for these compounds were observed to be deeply above the maximum operation temperature of the NMR spectrometer and therefore, preventing their direct estimation. However, the observation of a linear variation (r = 0.99) between Δν and the maximum operation temperature, allow us to estimated the Tc and ΔGǂ values for these compounds to be from 360.7 and 434.5 ºC and from 29.65 to 33.16 kcal mol-1 respectively (Table 2). Table 2 – Tc and ΔGǂ of some N-alkyl-2-alkylsulfanyl-acetanilides 3
Compd. Tc (°C) ΔGǂ (kcal/mol) 3a 360.7 29.65 3b 434.5 33.16 3c 385.5 30.16
Error ± 0.3 kcal/mol
As an example, N-(2-(ethylthio)phenyl)-N-ethylacetamide (3a): IR (�max/cm-1): 2958, 2928, 2857, 1660 (C=O), 1583, 1469, 1437, 1392, 1295, 1255, 1232, 1149, 1096, 1064, 1036, 733. 1H NMR (400 Hz, DMDO-d6): δ = 7.38-7.40 (m, 2H), 7.21-7.23 (m, 2H), 3.94 (dq, 1H, J = 14.0 Hz, 7.1 Hz), 3.08 (dq, 1H, J = 14.0 Hz, 7.1 Hz), 2.98 (q, 2H, J = 7.4 Hz), 1.62 (s, 3H), 1.25 (t, 3H, J = 6.9 Hz),
0.99 (t, 3H, J = 6.9 Hz) ppm. 13C NMR (100 MHz, DMDO-d6): δ = 169.3, 139.5, 137.3, 130.2, 129.3, 126.5, 125.9, 41.9, 24.7, 22.5, 14.0, 13.3 ppm. HRMS (ESI-TOF) m/z 224.10986 (224.11091 calcd. for C12H18NSO, [M+H+]).
Conclusions The presence of an alkylsulfanyl group in the ortho position of the serial of acetanilides herein present, reveals a dramatically effect on the restriction around Ar-N bond rotation responsible for the atropisomerism observed in this compounds. Moreover, the estimated Tc and ΔGǂ values are relatively high compared to other anilides already described in the literature, and reveals to increase as the N-alkyl chain (R1) increase, but decrease, in some cases, when the S-alkyl increase (R2).
References 1. Ramos, S. S., Reis, L. V., Santos, P. F., Almeida, P.
Hydrolysis of 3-alkyl-2-methylbenzoazol-3-ium iodides: na useful reaction, Simpósio 2010, UMTP, Universidade da beira Interior.
2. Oki, M. Application of Dynamic NMR Spectroscopy to Organic Chemistry; Wiley-VCH: Weinheim, 1985.
Acknowledgements This work was financed by FCT (Project PTDC/QUI-QUI/100896/2008) and COMPETE (Project PEst-C/SAU/UI0709/2011).
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Pulping Potential of Ailanthus altissima (Mill.) Swingle
P. Baptista1, A. P. Costa 1, M.E. Amaral1, R. Simões1 1 Research Unit of Textile and Paper Materials, University of Beira Interior, Covilhã, Portugal
Abstract In this work, Ailanthus altissima (Mill.) Swingle (tree-of-heaven) wood samples from different levels in the tree were analyzed in terms of chemical composition. The ash, extractives and lignin contents are approximately: 0.8, 4,5 and 26%, respectively. Selected wood samples were submitted to kraft cooking under different operating conditions, namely effective alkali charges, in order to evaluate their pulping potential. The best pulp yield obtained was close to 44%. The morphological pulp fibers characteristics are as follows: fiber length (weighted in length) - 0.86 mm; the fiber coarseness - 0.1097 (mg/m).
Introduction Ailanthus altissima (tree-of-heaven), is a member of the Simaroubaceae, family, native to China and North Vietnam, which has become invasive on all other continents except Antarctica [1]. The word Ailanthus, derived from ailanto, an Ambonese word means ‘‘tree of heaven’’ [2]. Ailanthus is a medium-sized tree which reaches maximum heights of 18–30 m depending on the growth conditions. It develops quickly thanks to its double strategy of reproduction [1,3]. The tree-of-heaven is a deciduous species that bears yellowish-green male and female flowers on different trees, its sexual reproduction leads to high production of winged fruits scattered by wind over long distances [3,4]. It also reproduces vegetatively by vigorous root suckers growing from root buds, and the allelopathic chemicals it produces, hence inhibiting the growth of neighbor plants [3,5,6]. It prefers rich and moist soils but tolerates also poor and dry soils. Besides, tree-of-heaven supports air pollution and may be able to sequester some pollutants. For this reason, it has been widely planted in urban areas worldwide to reduce the environmental pollution [4,7]. However, this tree has become a plague, not only by competing with native vegetation, but causing destruction on the roads, sidewalks, structures, piping, and orchards, due to its extensive root system. Invasive plants pose a threat to biodiversity and economy of the entire world [7]. Until now, there has been an only limited effort in developing biological control programs against tree-of-heaven [4]. However, since the oil crisis in the early 1970s and the growth of world population, the demand for new energy sources has increased. A wide availability of agricultural, agro-industrial wastes and plants that grow very quickly, as poplar, Ailanthus altissima, sunflower stalks, stems
tobbaco, and australis pragmites etc, make it possible to use these materials for energy applications and as chemical feedstocks [8]. Similarly, as society becomes more energy sensitive, the pulp and paper industry may also be challenged to defend the current practices of consuming only a small fraction of the whole wood. A large portion of this natural resource is either being left in the forest as residue or being used as a fuel source; a relatively inefficient use of one of nature's storehouses of energy [9,10]. In order to meet the future demand and to overcome the wood shortage, studies have been conducted to utilize new or alternative resources in the forest industries as raw material components for pulp and paper production in several countries [11]. The literature on ailanthus clearly shows it has been researched in a variety of countries for a variety of uses. These uses include ornamental planting, shelterbelts, afforestation and reforestation of "difficult sites," plantations for the culture of silkworms, and biomass production for fuelwood and for the production of fodder for goats and cattle [12]. Ferreira, et al. have achieved some reasonable results regarding the evaluation of the papermaking potential of A. altissima [13]. In this work, A. altissima timber was analyzed for its chemical and morphological properties in order to produce pulp. The A. altissima was cooked in wood kraft conditions using different effective alkali charges. The objective of the chemical pulping is the removal of lignin from the wood while preserving, as much as possible, the carbohydrates. However, it is not enough to simply let the lignin react with the alkaline reagents in the cooking liquor; it is also required to withdraw the dissolved lignin out into the free liquor, since the lignin remaining in the entrapped liquor can precipitate onto the wood after the cook, once the pH of the medium drops below 12 [14,15]. A decrease in the lignin content of unbleached pulp improves the economics and reduces the environmental impact of chlorine dioxide based bleaching processes. Such reasons explain the widespread acceptance of modified kraft process technologies in the pulp-and-paper industry in the last few years [14].
Materials and Methods Since A. altíssima is an invasive plant and is very present in our region, the wood obtained from some trees present in the forest of our city. The tree was about 20 years old, which corresponds to half of its life. The tree was divided into four lots of different diameters, being the 4th lot further divided into two lots: heartwood and sapwood.
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The chips were air dried, selected (SCAN-CM 40) and ground (TAPPI Standard T 264) for the analysis of chemical composition (lignin, ash and extractives). For the wood samples, the content in lignin was determined using the standard “Determination of Structural Carbohydrates and Lignin in Biomass” from NREL [16]. The extractives (ethanol and dichloromethane), water solubility, one percent sodium hydroxide solubility and ash amount were obtained following the T 204 om, T 207 om, T 212 om and the T 211 om TAPPI Standards, respectively. A rotatory digester was used to cook 25 g (o.d.) of chips at 160 ◦C and 165ºC, with a heating rate of 1.17, 1.55, 1.61 and 2.33ºC/min. The liquid to wood ratio were 5:1 and 4:1, and the time at maximum temperature were 60 and 90 min. Three different cooks with effective alkali charges of 20%, 22% and 24% (as NaOH) were
performed, always with a sulfidity of 30%. After cooking, the yield was determined and as well as the pulp kappa number (according Portuguese standard NP 3186). The determination of morphological properties of A. altissima kraft pulp fibers were determined by image analysis of a diluted suspension in flow chamber in Morfi®.
Results and Discussion The amounts of extractives, solubility in water and one percent sodium hydroxide, lignin and ash determined for wood of A. altíssima are described in Table 1. The reference levels were considered, 15, 35, 65 and 85% of the total height of the tree.
Table 1- The chemical composition of Ailanthus altissima (Mill.) Swingle
Components (%, w/w, on o.d. wood) Ailanthus altissima (height level in the tree)
85% 65% 35% 15%
Total Sapwood Heartwood
Extractives
Dichloromethane 1.20 0.58 0.66 0.75 0.71 0.65
Ethanol 1.95 1.30 1.17 1.24 0.90 1.56
water solubility 2.61 3.12 2.96 2.93 2.15 2.85
Total 5.76 4.99 4.78 4.93 3.77 5.07
1% sodium hydroxide solubility 19.49 16.59 19.61 18.67 18.29 18.55
Klason lignin 22.83 20.42 20.58 20.98 20.00 20.46
Acid soluble lignin 4.96 4.95 5.27 4.36 4.28 3.91 Total lignin 27.79 25.37 25.85 25.33 24.28 24.37
Ash content 0.85 0.85 0.89 0.85 0.76 0.80 The amounts of lignin are within the values reported by Khattak and Ghazi [17], Küçük [8], and Samariha and Kiaei [18], 22.19, 26.5 and 25.19%, respectively. In turn the extractives and ash content is similar to that found by Küçük [8] in this type of wood. The results of the different cooking made with the wood of A. altíssima are presented in Figure 1. As can be seen the increase of the reaction time to maximum temperature of cooking leads to an increase in the percentage of pulp and a decreased amount of uncooked material. However, the percentage of uncooked material is higher than expected considering the literature data. It was observed that grinding the raw material leads to a decrease of Kappa number, but income level shows no significant changes.
It was also found that increasing the effective alkali charge causes a slight increase in pulp yield and a decrease in Kappa number and the percentage of uncooked material. As to morphological analysis, fiber kraft pulp with a kappa number of 16 was used, the average fiber length determined was 0.862 mm for L1 (length weighted) and 0.747 mm for Ln (number weighted), the fiber width was approximately 24.1μm, the fiber coarseness 0.1097 mg/m. The values of fiber length and width are not far from those previously found for the same species by Khattak and Ghazi [16]: 0.89 mm and 21.05 μm for Ll fiber length and width, respectively.
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Figure 1 – Effect of cooking conditions on pulping
Conclusions
The wood chemical composition of the Ailanthus altissima falls within the range expected for hardwoods. The Klason lignin is between 20.0 and 22.8, extractives content are between 4.8 to 5.8. Despite showing favorable chemical composition, the wood samples have proven to be difficult to transform into pulp, which was revealed by the unexpected relatively high amount of uncooked material. According to our experimental results, the best cooking conditions were cooking temperature of 165°C with a residence time of 90 minutes, an effective charge of 22% (as NaOH) and a liquor/wood ratio of 4. References 1. Kowarik, I., and Säumel, I., Biological flora of Central
Europe: Ailanthus altissima (Mill.) Swingle, Perspectives in Plant Ecology, Evolution and Systematics, 8, 207–237, 2007.
2. Kundu, P., and Laskar, S., A brief resume on the genus Ailanthus: chemical and pharmacological aspects, Phytochem Rev., 9, 379-412, 2010.
3. Motard, E., Muratet, A., Clair-Maczulajtys, D., and Machon, N., Does the invasive species Ailanthus altissima threaten floristic diversity of temperate peri-urban forests?, Comptes Rendus Biologies, 334, 872-879, 2011.
4. Ding, J., Wu, Y., Zheng, H., Fu, W., Reardon, R., and Liu, M., REVIEW, Assessing potential biological control of the invasive plant, tree-of-heaven, Ailanthus
altissima, Biocontrol Science and Technology, 16:6, 547-566, 2006
5. Constán-Nava, S., Boneta, A., Pastor, E., and Lledóa, M.J., Long-term control of the invasive tree Ailanthus altissima: Insights from Mediterranean protected forests, Forest Ecology and Management 260, 1058–1064, 2010.
6. Albright, T.P., Chen, H., Chen, L., Guo, Q., The ecological niche and reciprocal prediction of the disjunct distribution of an invasive species: the example of Ailanthus altissima, Biol Invasions, 12, 2413–2427, 2010.
7. Ding, J., Reardon, R., Wu, Y., Zheng, H., and Fu, W., Biological control of invasive plants through collaboration between China and the United States of America: a perspective, Biological Invasions, 8, 1439–1450, 2006.
8. Küçük, M.M., Delignification of Biomass Using Alkaline Glycerol, Energy Sources, 27:13, 1245-1255, 2005.
9. Küçük, M.M., and Demirbas, A., Kinetic study on hydrolysis of biomass (Ailanthus altissima chips) by using Alkaline-glycerol solution, Energy Conversion and Management, 40, 1397-1403, 1999.
10. Jahan, M.S., Shamsuzzaman, M., Rahman, M.M., Moeiz, S.M.I., and Ni, Y., Effect of pre-extraction on soda-anthraquinone (AQ) pulping of rice straw, Industrial Crops and Products, 37, 164– 169, 2012.
11. Samariha, A., Kiaei, M., Talaeipour, M., and Nemati, M., Anatomical structural differences between branch and trunk in Ailanthus altissima wood, Indian Journal of Science and Technology, 4, 2011.
12. Feret, P.P., Ailanthus: Variation, cultivation, and frustration, Journal of Arboriculture, 11, 361-368, 1985.
Sample
Grinded
Pre-impregnation
Heating time (h)
Temperature (ºC)
Reaction time (min)
Effective alkali charges (%)
Liquid to wood ratio (L/kg wood)
0
5
10
15
20
25
30
35
40
45
1 1 1 1 2 2 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4
No No No No No No No No No No No No No No No No No No No No No No No No Yes
No No No No No No No No No No No No No No No No No No No No No No Yes Yes No
1.5 1.5 2.0 2.0 1.5 1.5 1.0 1.0 1.0 1.0 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 2.0 2.0 1.5 1.5 1.5
165 165 160 160 160 160 160 160 160 160 160 160 160 160 160 160 160 160 165 165 160 160 160 160 165
60 90 60 90 60 90 60 60 90 90 60 60 60 60 90 90 90 120 60 90 60 90 90 120 60
22 22 20 20 22 22 20 22 20 22 20 22 22 24 20 22 22 20 22 22 20 20 20 20 22
4 4 4 4 4 4 4 4 4 4 5 4 5 5 5 4 5 5 4 4 4 4 5 5 4
Pulp (%) Uncooked material( %) Kappa number
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13. Ferreira, P.J.T., Gamelas, J.A.F., Carvalho, M.G.V.S., Duarte, G.V., Canhoto, J.M.P.L., and Passas, R., Evaluation of the papermaking potential of Ailanthus altissima, Industrial Crops and Products, 42, 538– 542, 2013.
14. Santiago, A.S., and Neto, C.P., Eucalyptus globulus kraft process modifications: Effect on pulping and bleaching performance and papermaking properties of bleached pulps, Journal of Chemical Technology and Biotechnology, 83, 1298–1305, 2008.
15. Simão, J.P.F., Carvalho, M.G.V.S., and Baptista, C.M.S.G., Heterogeneous studies in pulping of wood: Modelling mass transfer of dissolved lignin, Chemical Engineering Journal, 170, 264–269, 2011.
16. NREL/TP-510-42618, Laboratory Analytical Procedure, “Determination of structural carbohydrates and lignin in biomass”.
17. Khattak, T.M., and Ghazi, J., Suitability of some non-commercial fast growing wood yielding trees growing in Azad Kashmir for the production of pulp and paper, Pak. J. Bot.,33, 729-732, 2001.
18. Samariha, A., and Kiaei, M., Chemical composition properties of stem and branch in Alianthus altissima wood, Middle-East Journal of Scientific Research,8, 967-970, 2011.
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Environmental applications of TiO2 electrodes prepared by DC-Magnetron Sputtering
S. Ferreira1, S. Sério2, M.E. Melo Jorge3, L. Ciríaco1, M. J. Pacheco1, A. Lopes1 1 Departamento de Química, UMTP, Universidade da Beira Interior, 6201-001 Covilhã, Portugal
2CEFITEC, Dep. Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal 3CCMM, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal,
Abstract The objective of this work was to assess the potential of TiO2 catalytic films, prepared by DC-magnetron sputtering, in the degradation of Acid Orange 7 (AO7) aqueous solutions using heterogeneous photo-catalysis or photoelectrocatalysis. Photolysis assays were also run. The assays were conducted in a system operating in batch mode, with stirring, for 4 hours, using a thermostatic bath to maintain constant the temperature (25 °C). Two UV lamps of 7 W each were used in the photocatalytic assays. In the electrolytic experiments, TiO2 films, deposited on a conductive glass (F-doped tin oxide (Sn02:F)), FTO substrate, or the just the FTO substrate, were used as anode and stainless steel as cathode. The applied current was 1 mA cm-2. In all the experiments, the initial concentration of dye was 50 ppm. The samples were analyzed for chemical oxygen demand (COD) and total organic carbon (TOC) content. Spectrophotometry UV-Vis. absorption spectra were also carried out. COD removals varied between 3% and 44% and TOC removals were always lower. These low removals actually contradict the removals in absorbance obtained from the absorption spectra, making it clear that the degradation mechanism is mainly by conversion of the dye molecule than by its mineralization. Spectrophotometric studies showed an effective AO7 removal ranging between 15 and 44 ppm. Although the good results that were obtained in this preliminary study, the catalytic effect of TiO2 in the assays involving catalytic processes have indicated that in the experimental conditions tested the TiO2 did not have the desired effect.
Introduction
The industrial development and the increase in population are causing an accumulation of persistent pollutants that degrade the environment and attacks ecosystems. Dyes and other aromatic compounds are among those responsible for this problem and it became necessary to develop processes that are able to stop this disaster. Although the biological methods are the cheapest way to reduce pollution in the liquid effluents, they are not always effective and has become imperative the development of new and more active methods, like photoelectrocatalytic methods. They are advantageous beyond doubt and photocatalysis is being intensively study due to its high efficiency in the removal of color from dye baths [1,2,3,4].
The degradation mechanism of the polluting compounds by photocatalysis is illustrated in Figure 1.
Figure 1 - Mechanism of the formation of the pair electron-hole in a TiO2 semiconductor in the presence of a pollutant molecule P (adapted from [5]). Conduction band electrons (eCB ) and valence band holes (hVB
+) are generated when TiO2 film is irradiated with light energy higher than its band gap energy (Eg, 3.2 eV). The photogenerated electrons could reduce the dye (pollutant molecule) or react with electron acceptors such as O2 adsorbed on the Ti(III)-surface or dissolved in water, reducing it to superoxide radical anion O2
• . The photogenerated holes can oxidize the organic molecule or react with OH or H2O oxidizing them into OH• radicals. Together with other highly oxidant species (peroxide radicals) they are reported to be responsible for the heterogeneous TiO2 photodecomposition of organic compounds such as dyes. According to this, the relevant reactions at the semiconductor surface causing the degradation of dyes can be expressed as follows [1]:
TiO2 + h (UV) TiO2(eCB + hVB+) (1)
TiO2(hVB+) + H2O TiO2 + H+ + OH• (2)
TiO2(hVB+) + OH TiO2 + OH• (3)
TiO2(eCB ) + O2 TiO2 + O2• (4)
O2• + H+ HO2
• (5) Dye + OH• degradation products (6) Dye + hVB
+ oxidation products (7) Dye + eCB reduction products (8) TiO2 catalysts can also be used in electrocatalysis or photoelectrocatalysis as anode. Figure 2 presents the mechanism of the electrodegradation at the anode of the organic molecule R mediated by OH•. The degradation can take place via combustion or conversion. In the latter
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case, if the resulting by-products are biodegradable, it may correspond to a successful process.
Figure 2 - Mechanism of the anodic oxidation of the organic molecule R, mediated by OH•.
Materials and Methods
The TiO2 films used in the degradation assays were deposited by DC reactive magnetron sputtering on conductive glass (F-doped tin oxide (Sn02:F)) substrates (FTO substrates) at room temperature in a custom made system as previously reported and described in detail elsewhere [6]. A titanium disc (99.99% purity) having 64.5 mm of diameter and 4 mm of thickness was used as sputtering target. The gases in the system were 99.99% pure Ar and O2, and partial pressures of these gases were separately controlled by mass flow controllers. The total pressure, PT, during the deposition was kept constant at 0.8 Pa and the partial pressure of oxygen was 0.8 Pa (i.e. 10% of PT). The sputtering power was kept at 1000 W and the deposition time was 80 min. In order to improve crystalline growth the as-sputtered films were thermal annealed in air at 400 C for 4 h in a tubular furnace.
The structural characterization was carried out on a Philips Analytical PW 3050/60 X’Pert PRO ( /2 ) equipped with X’Celerator detector and with automatic data acquisition (X’Pert Data Collector (v2.0b) software), using a monochromatized Cu K radiation as incident beam, 40 kV–30 mA. Diffractograms were obtained by continuous scanning in a 2 -range of 20–90 with a scan step time of 20 s.For the degradation assays, two 7 W UV lamps (254 nm) were deepen in the solution, with the TiO2 film (5 cm2 geometric area) between. The electrocatalytic experiments were conducted using a Potentiostat/Galvanostat, VoltaLab PGZ 301, as power source, being the applied current density 1 mA cm-2. The assays were performed in a three electrodes cell, of one compartment, being the anode the FTO/TiO2 film or just the substrate (FTO), the cathode a stainless steel foil and the reference electrode a commercial Ag/AgCl, KClsat. As model solution, 170 mL of an aqueous AO7 50 ppm solution in 5 g L-1 Na2SO4 was used. Before starting the test, the solution, with the electrodes immersed, was stirred for one hour. After that, a sample was collected from the solution and analyzed by UV-Vis spectrophotometry, to exclude the hypothesis of dye adsorption on the surface of the electrodes. The assay was then started and run during 4 h.
The samples collected during the assays were analysed, according to standard procedures for the following parameters: Chemical oxygen demand, using closed reflux dichromate titrimetric method; Total organic carbon (TOC), measured using a TOC analyser, Shimadzu TOC-V CPH; UV-Visible absorption spectrophotometric analyses, with absorbance (Abs) measurements from 200 to 800 nm, using a Shimatzu UV-1800 spectrophotometer. Results and Discussion
Figure 3 shows the XRD diffraction pattern obtained for the heated FTO/TiO2 film. It can be observed a small diffraction peak with (101) orientation at 2 near to 25º typical of the anatase TiO2 structure (JCPDS/ICDD 21-1272). The average crystallite size for the TiO2 film was calculated from the broadening of this diffraction peak using the Scherrer’s formula, D = 0.9 /B cos , where is the wavelength of Cu K radiation, B is the full width at half maximum (FWHM) of XRD peaks and the Bragg diffraction angle of the line. A value of ~60 nm for the anatase TiO2 crystallite size was estimated. All the other reflections correspond to the FTO substrate.
Figure 3. XRD diffraction pattern of TiO2 deposited on FTO substrate.
Table 1 presents the removals in COD, TOC and AO7 concentration, determined by UV-Vis spectrophotometry at 485 nm, for the different assays performed, with the FTO and with FTO/ TiO2 film. The variation in time of absorbance, measured at 485 nm, for those assays is depicted in Figure 4. COD removals in the assays performed with FTO/TiO2 film are higher than those obtained in the assays performed with the substrate alone.However, the best COD removal was obtained in the photolysis assay, which signifies that the most effective process for the degradation of AO7 is the UV light, and the presence of the substrate or substrate+TiO2 film only prevents light to reach the solution. TOC removals are negligible and COD and color removals are similar, meaning that the
123
degradation of the dye happens mainly by a conversion mechanism. In Figure 5, the spectra for the samples collected during some of the performed assays are presented. There is a regular decay in time of the absorbances in the visible region. On the other hand, at UV wavelengths these decay is not so regular and, in some cases, there is an increase in the absorbances measured in the region 200-300 nm, which may be due to the break of the azo bond, with the consequent increase in the aromatics concentration, that absorbe in that region of the spectrum.
Table 1. Removals of the monitored parameters after 4 h assay. AO7 concentration determined by UV-Vis at 485 nm.
Removal Processes
AO7* / ppm % COD
% TOC
Photolysis 41 44 3
Photocatalysis (substrate) 15 3 3
Electrocatalysis (substrate) 36 3 0
Photoelectrocatalysis (substrate) 37
38 3
Photocatalysis (TiO2) 24 32 0
Electrocatalysis (TiO2) 24 5 0
Photoelectrocatalysis (TiO2) 44 41 0
*Variation of AO7 concentration during the assay.
Figure 4 – Variation with time of the absorbance, measured at 485 nm, for the different assays performed.
Conclusions
From the degradation study of AO7 with TiO2 films, performed with different techniques, the following conclusions can be drawn: In general, AO7 degradation is possible using TiO2 films, either by photocatalysis, electrocatalysis or photoelectrocatalysis, since AO7 removals between 15 and 44 ppm were observed only after 4 h degradation.
Good color removal was detected by UV-Vis spectrophotometry, being, however, COD removals lower and TOC removals almost inexistent.
Figure 5 – UV/Vis spectra for the assay of photoelectrolysis with TiO2 film
TiO2 films have not enough stability when current density is higher than 1 mA cm-2.
After 4 h assay, the absorbance removal at 485 nm was almost complete in photoelectrolysis process, being lower for all the others processes.
Photolysis presents better results than TiO2 photocatalysis, probably because the most influent factor is the UV light that is prevented from reaching the solution due to the presence of the film.
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References 1. Ioannis K. Konstantinou, Triantafyllos A. Albanis,
2004. TiO2-assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations: A review, Appl. Catal. B-Environ. 49, 1-14.
2. Akpan U.G., Hameed B.H., 2009. Parameters affecting the photocatalytic degradation of dyes using TiO2-based photocatalysts: A review, J. Hazard. Mater. 170, 520–529.
3. Soutsas K., Karayannis V., Poulios I., Riga A., Ntampegliotis K., Spiliotis X., Papapolymerou G., 2010. Decolorization and degradation of reactive azo dyes via heterogeneous photocatalytic processes, Desalination 250, 345-350.
4. Barrocas, B., Monteiro, O.C., Melo Jorge, M.E., Sério, S. 2013. Photocatalytic activity and reusability study of nanocrystalline TiO2 films prepared by sputtering technique, Appl. Surf. Sci., 264, 111-116.
5. Chong, M., Jin, B., Chow, C., Saint, C. 2010. Recent developments in photocatalytic water treatment technology: A review. Water Res. 44, 2997-3027.
6. Sério, S. Melo Jorge, M.E., Maneira, M.J.P., Nunes, Y. 2011. Influence of O2 partial pressure on the growth of nanostructured anatase phase TiO2 thin films prepared by DC reactive magnetron sputtering, Mat. Chem. Phys., 126, 73-81.
Acknowledgements
Financial support from FEDER, Programa Operacional Factores de Competitividade – COMPETE, and FCT, for the projects PTDC/AAC- AMB/103112/2008 and PEst-OE/CTM/UI0195/2011 of the MT&P Unit
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Heavy metals monitoring during the electrochemical treatment of municipal landfill leachates
A. D. Fonseca, P. Spranger, A. Fernandes, L. Ciríaco, A. Lopes, M.J. Pacheco UMTP and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal
Abstract
The aim of this study is to evaluate the removal of heavy metals (Fe, Zn and Cr) during an electrochemical combined treatment, electrocoagulation (EC), using a consumable iron anode, followed by anodic oxidation (AO) with a BDD anode, of a landfill leachate samples, collected in a municipal landfill in the Beira Interior region. In EC experiments, it was observed an iron content fluctuation, mainly due to the cycles of iron hydroxyl formation and precipitation. During AO, the iron removal was 85%. After EC, zinc and chromium content removals were about 65%. After the combined treatment, removals were almost complete.
Introduction
Solid wastes containing heavy metals and other species can be a serious environmental problem. Once released to the environment, these species may accumulate in soils in different forms, as water-soluble extractable compounds or linked to carbonates, iron–manganese oxides and organic matter. The species in the solid waste that are soluble and extractable in water are considered bioavailable and are likely to be transported to the water and, as a consequence, can be absorbed by plants and can eventually bioacumulate in the food chain [1]. In some cases, these solid wastes containing heavy metals are disposed in municipal sanitary landfills. The heavy metals can remain trapped in the landfills and eventually be released to the environment, due to generation of leachates caused by the rainwater percolation through the solid wastes and wastes decomposition [2].In fact, compared to the total amount of heavy metals disposed into landfills the content of heavy metals in leachate is relatively low. The major part of the metals is retained in the landfill. As a consequence, it must be expected that leaching of heavy metals from the landfills will continue for a long time [3].
Besides heavy metals, leachates also contain various pollutants such as organic matter, biodegradable and non-biodegradable, ammonia-nitrogen, chlorinated organic and inorganic salts
[4]. Some of these pollutants can be removed by biological treatment but heavy metals and non-biodegradable organic matter are bio-refractory.
So, the leachate treatments to reduce high
contents in organic matter and simultaneously heavy metals contents represent a big challenge. Thus, a combined treatment approach may be the solution to minimize the environmental impact of these complex wastewaters. In this context, several studies have proved the feasibility of electrochemical technologies, namely electrocoagulation (EC) and anodic oxidation (AO), for the treatment of landfill leachates [5,6].
The objective of this study is to evaluate the removal of heavy metals (Fe, Zn and Cr) during a combined treatment, EC followed by AO, of leachates coming from a municipal landfill in the Beira Interior region.
Materials and Methods
Sample collection The leachate samples were provided by a Beira
Interior municipal sanitary landfill. The samples were collected in containers of 25
L, just before the biological treatment. In the laboratory, the samples were stored at 4ºC until processing and analysis.
Electrochemical Experiments Electrocoagulation experiments were
conducted in batch mode, without stirring and using 500 mL of leachate. Iron electrodes were used as cathode and as anode, both with an immersed area of 40 cm2, with a 1.0 cm gap between them. All experiments were conducted with an applied current intensity of 2.5 A, at room temperature and without addition of background electrolyte, during three hours. After the EC treatment, the samples were allowed to settle and the supernatant liquid was then submitted to the anodic oxidation treatment. Anodic oxidation experiments were conducted in batch mode, with stirring, and using 200 mL of the electrocoagulated effluent, during eight hours. A BDD anode, with an immersed area of 20 cm2, and a stainless steel cathode, with identical area, were used. Different current intensities were applied, namely, 1.0 and 1.4 A. During both electrochemical experiments,
126
samples were withdrawn at various time intervals and analyzed for the total Fe, Zn and Cr content.
Analyses
The samples withdrawn during EC were centrifuged and 10 mL of the supernatant solution was submitted to an HCl-HNO3 acid digestion according to a procedure described in the Standard Methods for the Examination of Water and Wastewaters [7]. The AO samples were submitted to the same treatment without the centrifugation step.
The total Fe, Zn and Cr contents were determined by Flame Atomic Absorption Spectrometry, using a SP9 Pye Unicam apparatus.
All glassware used in the analyses had been pre-cleaned and acid-washed before use. All reagents were of analytical grade and were used without further purification.
All tests were repeated at least twice, to guarantee the reproducibility of the results.
Results and Discussion
During EC, the iron consumable anode oxidizes and iron ions are formed. In solution, these ions hydrolyze and, depending on the medium pH, different polymeric hydroxides may be formed. These polymeric hydroxides are excellent coagulation agents, which have strong affinity for colloids, dispersed particles and ionic species forming flocs that can be removed by sedimentation and/or flotation [8]. In the present study, in order to understand the iron behavior during the EC treatment, the variation of iron in the solution was monitored and results are presented in Figure 1.
0
150
300
450
600
0 30 60 90 120 150 180
[Fe]
/ppm
t/min Figure 1 – Evolution of dissolved iron during EC treatment, performed at applied current intensity of 2.5 A, during 3 h.
In the first 45 min of the EC treatment, the dissolved iron content in the wastewater increased sharply, due to the oxidation of the iron consumable anode that generates Fe2+ in solution, followed by a fall, due to the growth of polymeric iron hydroxyl flocs, which were transformed in non soluble forms. The iron content fluctuation during EC treatment is mainly due to these cycles of iron hydroxyl formation and precipitation.
Figure 2 presents the total Fe, Zn and Cr contents before and after three hours of EC treatment and after the combined treatment, three hours of EC followed by eight hours of AO.
Figure 2- Heavy metal concentration before and after EC and after the combined treatment EC (3 h) + AO (8h): (a) iron; (b) chromium; (c) zinc.
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As it was expected, for the reasons mentioned previously, in the end of the EC treatment, the iron content value is higher than the initial value (Fig. 2 a). During the anodic oxidation performed with the highest current intensity, 85% of the iron was removed.
Regarding the total of chromium and zinc concentrations at the end of the EC and the combined treatment (Fig. 2 b and c), they have decreased during both processes. After the EC, the zinc and chromium removals were 63% and 67%, respectively. In the final of the combined treatment, for the AO performed at the applied current intensity of 1.4 A, the chromium removal was almost complete, its concentration was lower than the limit of detection of the method. In the case of zinc, the best removal, 96%, was obtained for the applied current intensity of 1,0 A.
Heavy metals removal by these two combined electrochemical methods may envolve two processes: in the EC, the co-precipitation with the formed iron hydroxyl polymeric flocs and, simultaneously, the reduction in the cathode, with the correspondent deposition on it, and in AO mainly due to the latter process.
Conclusions
During electrocoagulation there is an increase in the iron content, mainly due to the oxidation of the iron consumable anode. The iron content fluctuation during EC is mainly due to the cycles of iron hydroxyl formation/precipitation. During AO, 85% of the iron formed during EC, which remains in the EC treated effluent, is removed and the removal efficiency increases with applied current density. At the end of the combined treatment, the chromium and zinc are almost completely removed; the legal limits for disposal into the municipal sewage were accomplished.
References
[1] T.A. Maranhão, J.S.A. Silva, R.M. Andrade, V.L.A.F., Bascuñan, F.J.S Oliveira, A.J. Curtius. Determination of As and Hg in acetic extract by vapor generation coupled to atomic spectrometry for solid waste classification. Microchem. J. 106 (2013) 139-146.
[2] M. Aucott. The Fate of Heavy Metals in Landfills. TheTidal Exchange 21 (2008) 1-5.
[3] Heavy Metals in Waste-Final report. E3 Project ENV.E.3/ETU/2000/0058. European Commission DG ENV (2002).
[4] Z.P. Wang, Z. Zhang and Y.J. Lin Landfill leachate treatment by coagulation-photooxidation process. J. Hazard. Mat .95 (2002) 153-159.
[5] A. Fernandes, M.J. Pacheco, L. Ciríaco and A. Lopes. Anodic oxidation of a biologically treated leachate on a boron-doped diamond anode. J. Hazard. Mater.199-200 (2012) 82-87.
[6] D. Norma, A. Fernandes, L. Ciriaco, M.J. Pacheco, A. Lopes. Electrocoagulation and Anodic Oxidation as a Complement of Biological Treatment of Sanitary Landfill Leachates. Port. Electroch. Acta 30 (2012) 281-294.
[7] Eaton, A., Clesceri, L., Greenberg, A., 2005. Standard methods for examination of water and wastewater, 21st Ed., APHA, AWWA, WEF, Washington.
[8] Liu H, Zhao X, Qu J. Electrocoagulation in water treatment. In:Comninellis C, Chen G, ed.. Electrochemistry for the environment. NewYork. Springer Science+Business Media, LLC; 2010.
Acknowledgement Financial support from FEDER, Programa Operacional Factores de Competitividade – COMPETE and FCT, for the projects PTDC/AAC-AMB/103112/2008, PEst-OE/CTM/UI0195 /2011 of the MT&P Unit and grant SFRH/BD/81368/2011
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Removal of Reactive Orange 16 by Biosorption
C. Louro1, I.Gonçalves 1, M.I. Ferra1 and H.M. Pinheiro2 1University of Beira Interior, Chemistry Department - UTPM, R. Marquês D’Avila e Bolama, 6200 - Covilhã, Portugal 2 Centre of Biological and Chemical Engineering, Technical University of Lisbon, Av. Rovisco Pais – 1049-001 Lisbon, Portugal Abstract The objective of the present work the adsorption of Reactive Orange 16 by dried red grape pomace (GP) was investigated. Experiments were carried out in batch systems, at 37 2oC, with magnetic stirring. The particle size (ø) and GP concentration could have a significant effect on dye adsorption. The adsorption capacity was higher for particles with ø < 0.25 mm. In this particular case the mass variation doesn’t seem to alter the adsorption efficiency. However, for particles retained in sieves of 0.25 mm, the adsorption capacity was clearly higher for a mass of 1g. A compromise between the GP adsorption capacity and the energy consumption associated to milling process along with the increase of leachates in liquid phase should meanwhile be considered in the definition of the most reliable situation.
Introduction Numerous approaches on new ways to remove synthetic chemical compounds from the environment have been greatly improved in last decades. Cheap and easily available materials such as waste from industry and agriculture have been tested as adsorbents for pollutants removal from a water matrix. Over 1 million tons dyes are produced per year, of which 50% are textile dyes (Asgher, 2012). Due to the growing awareness and environment concerns removing colour from water has gained primordial importance. Some reactive dyes are likely to pass through conventional wastewater treatment plants untreated and their elimination after biological treatment could be performed by polishing technologies. In this context, adsorption by natural resources has gained prominence as an effective process to remove dyes, being cost-effective and environment friendly. Grape pomace (GP) is one of the most important residues of wine making industry that is mainly seeds, skins and pulp. It is estimated a production of 18-20kg GP/100kg of grapes (Spanghero et al., 2009). Grape pomace should be looked at as a natural material that is widespread, cheap and requires little processing for reuse. It may have potential as sorbent since it contains organic compounds, namely lignin, cellulose, hemicellulose and polyphenols that could facilitate dyes binding trough different interactions. The sorption mechanisms could occur among others, by complexation, ion-exchange and hydrogen bonds. The sorption capacity also depends on factors such pH, temperature, type and concentration of sorbent and sorbate, and particle size (Detroy and Hesseltine,1978; Silva, 2003; Grini, 2005). It is also a function of the accessibility of the pollutants to the inner surface of the adsorbent, and as a consequence of their size. The aim of
the present work was to investigate the influence of mass and particle size of red grape pomace on adsorption of a reactive dye (Reactive Orange 16).
Materials and Methods Raw material Grape pomace, GP, used in the experiments is a by-product of winemaking industry, for red wine production. Before performing experiments it was dried, milled and sieved. It was gently supplied by a winery located in Central Region of Portugal. Feeding solution Selected azo dye Reactive Orange 16 (RO16) was purchased from Sigma-Aldrich (Germany). Hydrolysed dye form (60 mg/L) was added to a buffer phosphate solution (1.28 g Na2HPO4 /L and 0.42 g NaH2PO4/L) and used as feeding. Analyses UV-visible absorption spectra were run in a Helios Alpha spectrophometer (Unicam, UK). Colour was measured at the maximum visible absorbance wavelength of the dye (401 nm). Absorbance at this wavelength was correlated with dye concentration and used to quantify decolourisation. Suspended solids (SS), volatile suspended solids (VSS) and pH in liquid samples were determined according to standard procedures (APHA, 2005). Total Organic Carbon (TOC) was quantified by combustion catalytic oxidation/NDIR method in a TOC-Vcsh Shimadzu. Adsorption experiments Adsorption tests were carried out in batch mode, in bottles of 100 ml capacity at 37 2oC with magnetic stirring. Different GP masses (0.50 and 1g) and granulometries (particles retained in sieve opening sizes of 0.25 and 0.42mm and smaller than 0.25mm) were used. Dried grape pomace has a high content of volatile solids, so of organic matter (Table 1). Table 1 – Grape pomace characterization
Samples were collected and monitored as a function of time (0-420min). GP was added to flasks into which 50
Grape Pomace (GP) Solids Particle size(ø)
TS (g /g GP)
VTS (g/g GP)
bellow 0.25 mm 0.950±0.005 (n=3)
0.810±0.010 (n=3)
0.25- 0.42 mm 0.934±0.006 (n=3)
0.845±0.006 (n=3)
greater than 0.42 mm 0.880±0.050 (n=2)
0.869±0.050 (n=2)
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mL of feeding solution containing the dye was then poured. Experiments without dye in feeding model solution were also run and used as blanks and in leaching studies in order to assess the rate at which the organic matter is being solubilised. Tests were performed in triplicate. Results and Discussion From leaching experiments it was clear that compounds are leached from the solid to the liquid phase mainly in the first 60 min (Figure 1a). This indicates a sharp increase of the organic load in liquid phase, particularly for tests with ø bellow 0.25mm. a) b)
Figure 1 - Examples of UV-visible spectra for blank (a) and RO16 tests (b) run in function of time (min) Although solubilisation of organic substrates present in sorbent could affect adsorption rate as well as the binding dye-sorbent mechanisms, results have shown that this was not the case, even for experiments run with a particle size bellow 0.25mm. UV-visible spectra (Figure 1) depicted a peak at 280 nm that is characteristic of lignin like compounds, which increased due to leaching process. A steadily decrease of the main characteristic peaks of the dye in the visible range (401 and 500nm) was also observed (Figure 1b), which could be attributed to dye adsorption, since no significant spectral alterations occurred in the first 20-30 minutes, when the adsorption equilibrium was reached. Residual dye concentration in aqueous phase decreased sharply for a mass of 0.5g and a particle size bellow 0.25mm (Figure 2) indicating a fast adsorption rate. For a mass of 1g the adsorption rate was almost similar in tests with a particle size bellow 0.25mm and 0.25-0.42mm. The amount of adsorbed dye per unit mass of sorbent (GP), q, corroborate results displayed in Figure 2. It was also figured out a progressive enhancement of q with the decreasing of particle size. The influence of particle size on q was more pronounced for low GP masses. Although the adsorption capacity had been in general greater for particle sizes bellow 0.25mm, the sharp increase of the leached organic load from the sorbent deserve particular attention, since a further treatment is still required. So results indicate that particle sizes 0.25-0.42mm and mass of 1g could be a good choice.
a)
b)
Figure 2 - Examples of time courses of residual dye concentration in adsorption tests with a GP mass of 0.5g (a) and 1g (b) Conclusions Mass and particle size play an important role on RO 16 bioadsorption in grape pomace, independent of the leaching process. In this context adsorption of dyes by natural sorbents should not be assumed as a finishing treatment technology, and a compromise between both adsorption/biodegradation processes could be achieved for instance, in integrated technologies, in order to meet a complete removal of pollutants. Results suggest that GP, a low cost biosorbent, is a viable alternative to chemical adsorbents, making the valorization of this byproduct possible. It could also be considered amenable for biodegradation, avoiding environment impacts associated to its disposal. References 1. APHA AWWA, 2005, Standard Methods for the Examination of
Water and Wastewater, 21 th edition., American Public Health Association/ American Water Works Association/Water Environment Federation, Washington DC, USA.
2. Asgher, M. (2012). Water Air Soil Pollution, 223: 2417-2435. 3. Detroy R.W., Hesseltine C.W. (1978). Process Biochemistry. 13
(9): 2-8. 4. Grini, G. (2006). Bioresource Technology, 97: 1061-1085. 5. Silva, L.M.L.R. (2003).“Caracterização dos subprodutos da
vinificação”, Millenium online (Revista do ISPV), 28:123-133. 6. Spanghero,M., Salem, A.Z.M. and Robinson, P.H. (2009). Animal
Feed Science and Technology, 152: 243-255.
0
20
40
60
80
0 10 20 30
Residualdyeconcentration
(mg/L)
t(min)
greater than 0.42mm 0.25 0.42 mm bellow 0.25 mm
0
20
40
60
80
0 10 20 30
Residualdyeconcentration
(mg/L)
t (min)
greater than 0.42 mm 0.25 0.42 mm bellow 0.25 mm
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Critical temperature and free energy of activation evaluation of new 2-alkoxy-N-alkylacetanilide atropisomers
P. M. S. Leite1, S. S. Ramos2, R. E. F. Boto1, P. Almeida1 1 CICS, Health Sciences Research Center, University of Beira Interior, 6201-001 Covilhã, Portugal; 2UMTP and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã,
Portugal
Abstract The synthesis of some atropisomeric ortho-substituted anilides 2 and their dynamic 1H NMR spectroscopic studies are reported. Dynamic NMR indicate that almost only two of the four possible rotamers are present in solution, with population ratios of 1:1. The measured free energy of activation to interconversion of the rotamers ranged from 18.85 to 19.16 kcal/mol.
Introduction The reaction of some benzoxazolium salts 1 in the presence of residual water leads to the heterocyclic ring opening yielding the corresponding 2-alkoxy-N-alkylacetanilides 2. Using 1 as useful synthon for 2 (scheme)1, the selective introduction of different R1 and R2 alkyl groups, which is not easily carried out starting from ortho-hydroxyaniline, is easily allowed. The 1H NMR inspection of 2 revealed two non-equivalent geminal protons in the methylene group directly link to the amide nitrogen and therefore the existence of 2 as a mixture of atropisomers. Further, the free energy of activation (G‡) and the critical temperature (Tc), the lowest temperature at which the two rotamers merge and the barriers of interconversion between these two forms are eliminated, could be easily estimated by Variable Temperature NMR (VT-NMR).
R1 = Ethyl, Propyl or Hexyl; R2 = Ethyl, Propyl or Hexyl Scheme – Synthetic procedure
Materials and Methods Reactions were monitored by thin layer chromatography (TLC) eluted with CH2Cl2/MeOH (9:1). Column chromatography was performed on silica gel (Fluka-Kielselgel 60Å, 63-200 μm). The structures of the isolated products 2 were characterized by IR, 1H and 13C NMR spectroscopy, and electrospray ionization mass spectrometry (ESI-TOF). The IR spectrum of compounds
2 showed absorption at 1656-1660 cm-1 indicating the presence of an amide. The mass spectra displayed [M+H]+ peaks at appropriate m/z values.
NMR spectra were recorded at 400 MHz for 1H and at 100 MHz for 13C, referenced to the residual protonated solvent. The temperature was calibrated before the VT experiments by means of a thermocouple which has an uncertainty not exceeding ± 1 °C.
General procedure for the hydrolysis of 3-alkyl-2-methylbenzothiazol-3-ium iodides 1 to the corresponding N-(2-(ethoxy)phenyl)-N-alkylacetamides 2:
A solution of 3-alkyl-2-methylbenzoxazolium iodide 1 (1.0 mmol) and triethylamine (1.1 mmol) in 96% ethanol (100 mL) was heated under reflux. The reaction was complete in 30 to 60 min. The solvent was removed under reduced pressure and the crude reaction product was dissolved in ethanol. Following the addition of sodium hydroxide (1.2 mmol with reference to salt 1) and the appropriate alkyl iodide (1.0 mmol), the reaction mixture was heated under reflux for more 2 to 5 hr. After completion of the reaction, the solvent was removed under reduced pressure, the crude residue was dissolved in CH2Cl2 and extracted sequentially with 10% aqueous HCl and 10% aqueous NaOH. The organic layer was then washed with water, dried over anhydrous Na2SO4 and evaporated to dryness. The resulting pinky-red oil was purified by column chromatography using dichloromethane-methanol (from 9.5: 0.5 to 9:1) as eluent. The pure brown yellowish products are obtained in moderate to good yields.
Results and Discussion The atropisomerism within a serial of 2-alkoxy-N-alkylacetanilides 2, was confirmed by the observance of the non-equivalence of the geminal NCH2 protons in the 1H NMR spectra, despite no individual characterization of each atropisomer, neither the relative proportion between the two forms could be achieved by direct NMR analysis. However, VT-NMR experiments of 2 DMSO-d6 solutions, where the temperature was varied between room temperature and the maximum operating apparatus temperature (150 ºC), witnessed the expected broadening and coalescence of the methylene signals, yielding one single signal (Figure), as result of to the rapid interconversion between the two conformers at the critical
O
R2
N
R1
COCH3
I
O
N
R1
2 1
131
temperature. Further, the Tc and the rate constant Kc (s-1) derived from Δν (Table 1 ), allows to estimated the free energies of activation (G‡) (Table 2) using the Eyring equation and the rate constant (Eqs. 1-3)2.
Kc = πΔν/2 = 2.22Δν (1)
ΔGǂ = 2.303 R Tc (10.319 + log Tc/Kc) (2)
ΔGǂ = 4.569 x 10-3 Tc (10.319 + log Tc/Kc) (3)
25 °C 75 °C 115 °C
Figure – Example of 1H NMR signals of the two hydrogens (N-CH2 group) obtained in a DMSO-d6 solution at different
temperatures (R1 = R2 = Ethyl)
Table 1 – Δν and Kc (s-1) of representative 2-alkoxy-N-alkylacetanilides 2 estimated by VT-NMR
Compd. R1 R2 δ1 (ppm) δ1 (ppm) Δν Kc (s-1)
2a Et Et 3.6450 3.4300 86.03 190.99 2b Pr Et 3.5771 3.3519 90.11 200.04 2c Hex Et 3.6331 3.4071 90.43 200.75
Δν = (δ1 – δ2) x 400.13 Whereas acetanilides analogues for 2, when the O-alkyl group is replaced by a relative more bulky S-alkyl group in the ortho-position, it is only possible to estimate the Tc and G‡ by extrapolation since the critical temperature is largely above the operation temperature of the NMR spectrometer. In spite of that, for the acetanilides 2 herein presented, possessing a smaller O-alkyl bulky group in the ortho position, they still confer the existence of atropisomerism at room temperature and allows the direct estimation of both Tc and G‡ . Table 2 – Tc and ΔGǂ of representative 2-alkoxy-N-alkylacetanilides 2
Compd. Tc (°C) ΔGǂ (kcal/mol) 2a 115 18.85 2b 120 19.06 2c 122 19.16
Error ± 0.3 kcal/mol
As an example, N-(2-(ethoxy)phenyl)-N-ethylacetamide (R1 = R2 = Ethyl): IR (�max/cm-1): 2958, 2928, 2857, 1660 (C=O), 1583, 1469, 1437, 1392, 1295, 1255, 1232, 1149, 1096, 1064, 1036, 733. 1H NMR (400 Hz, DMDO-d6): δ = 7.34 (dt, 1H, J = 6.2 Hz, 1.7 Hz), 7.22 (dd, 1H, J = 6.2 Hz, 1.7 Hz), 7.13 (dd, 1H, J = 6.8 Hz, 1.4 Hz), 6.99 (dt, 1H, J = 6.2 Hz, 1.4 Hz), 4.02-4.15 (m, 2H), 3.65 (dq, 1H, J = 13.7 Hz, 7.0 Hz), 3.43 (dq, 1H, J = 13.7 Hz, 7.0 Hz), 1.64 (s, 3H), 1.30 (t, 3H, J = 7.0 Hz), 0.96 (t, 3H, J = 7.3 Hz) ppm. 13C NMR (100 MHz, DMDO-d6): δ = 169.6, 154.7, 131.4, 130.3, 129.8, 121.3, 113.7, 64.0, 42.6, 22.4,
15.1, 13.3 ppm. HRMS (ESI-TOF) m/z 208.13391 (208.13375 calcd. for C12H18NO2, [M+H+]).
Conclusions The observed atropisomerism in acetanilides 2 is due to the presence of an alkoxy bulky group at the ortho position. In these acetanilides, the Tc value is dependent of the nature of the alkyl chain at the nitrogen atom, which is expected regarding major restrictions around the Ar-N bond while the size of the N-alkyl group increases. As a final remark, it can be claimed that the existence of compounds 2 as a mixture of atropisomers expands the interest in the exploration of these compounds.
References 1. Ramos, S. S., Reis, L. V., Santos, P. F., Almeida, P.
Hydrolysis of 3-alkyl-2-methylbenzoazol-3-ium iodides: na useful reaction, Simpósio 2010, UMTP, Universidade da beira Interior.
2. Oki, M. Application of Dynamic NMR Spectroscopy to Organic Chemistry; Wiley-VCH: Weinheim, 1985.
Acknowledgements This work was financed by FCT (Project PTDC/QUI-QUI/100896/2008) and COMPETE (Project PEst-C/SAU/UI0709/2011).
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Simulações de Antenas Têxteis
C. Loss, R. Salvado1, P. Pinho, R. Gonçalves2 1Unidade Investigação de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, 6201-001 Covilhã, Portugal. E-
Mails: [email protected], [email protected]; 2Instituto de Telecomunicações, Campus Universitário de Santiago, 3810-135 Aveiro, Portugal. E-Mails:
[email protected], [email protected]
Resumo Devido ao facto dos dispositivos electrónicos
portáteis se terem tornado parte integrante do quotidiano dos indivíduos, o desenvolvimento de
tem sido um desafio premente, tanto nos domínios civis como nos militares.
Para permitir a implantação dos sistemas electrónicos mais confortavelmente no vestuário e diminuir a preocupação com o curto tempo de vida das baterias e os problemas ambientais associados ao uso das mesmas, apresentamos a simulação de duas antenas que foram concebidas para efetuar a recolha de energia ambiente resultantes do estudo das propriedades específicas exigidas aos materiais têxteis. Introdução
Num futuro não muito distante, o ser humano poderá conter sobre si uma gama grande de dispositivos e sensores, embebidos no vestuário, capazes de realizar uma monitorização contínua. Esta função, requer uma antena que possa ser discretamente integrada na roupa, sem perturbar o movimento do utilizador [1], [2]. Para a obtenção de bons resultados, as antenas vestíveis precisam ser finas, leves, de fácil manutenção e integração nos circuitos RF, robustas, e além disso, devem ser de baixo custo de fabricação e, respectivamente de comercialização [2-4] .
Neste estudo, vamos focar as antenas planares tipo patch microstrip, pois além de apresentarem todas estas características, estas antenas ainda são adaptáveis a
qualquer superfície e apresentam grande versatilidade de uso.
Estas antenas são geralmente constituídas pela sobre posição de camadas metálicas e dielétricas. Portanto uma antena patch microstrip flexível requer materiais condutores flexíveis para o patch e para o plano de massa e, materiais dielétricos flexíveis para o substrato [1],[3]. Além disso, as antenas planares irradiam perpendicularmente ao seu plano de massa, que serve de escudo às radiações, resultando que apenas uma fração muito pequena da radiação emitida é absorvida pelo corpo humano [1],[2].
O conhecimento das propriedades elétricas e eletromagnéticas dos materiais é essencial para um bom dimensionamento e um bom desempenho da antena. As propriedades elétricas dos tecidos condutores devem ser caracterizadas com precisão e muitas vezes estes dados já são enviados pelos fornecedores, como por exemplo as companhias americanas Less EMF Inc. e Shieldex Trading. No entanto, menos informação é encontrada a respeito da caracterização das propriedades eletromagnéticas dos têxteis dielétricos. Revisão dos materiais utilizados em antenas flexíveis
A tabela seguinte apresenta as principais características dos materiais têxteis que foram utilizados para desenvolver antenas flexíveis.
Tabela 1 - Tabela comparativa dos materiais têxteis utilizados no design de antenas flexíveis [fonte: autor]
REFERENCE ANTENNA FREQUENCY DIELECTRIC MATERIAL
CONDUCTIVE MATERIAL
MATERIAL THICKNESS r
[5] Dual-band GSM 900MHz and Bluetooth 2.4GHz
Unspecified textile material 0,236 mm 3,29 0,0004 -
[6] Bluetooth applications Bluetooth applications Fleece fabric 3 mm 1,04 - Knitted copper fabric
[7] GPS antenna with circular
polarization GPS antenna with
circular polarization Cordura 0.5 mm
Between 1.1 and
1.7.
- Copper tape
[2] Bluetooth applications Around 2,4 GHz
Polyamide spacer
fabric 6 mm 1,14 negligible Silver copper nickel plated
woven fabric
[2] Bluetooth applications Around 2,4 GHz
Woolen felt 3.5 mm 1,45 0,02
Silver copper nickel plated woven fabric
[8] Rectangular-ring textile
antenna More than 190 MHz.
Fleece fabric 2,56 mm 1,25 - Flectron
[9] Dual-band coplanar patch
antenna 2,45 and 5,8 GHz
wireless bands Felt 1,1 mm 1,30 0,02 Zelt
[1] ISM Around 2,4 GHz
Foam 3,94 mm 1,52 0,012
Patch: Zelt Ground plane: Flectron
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Após análise desta tabela podemos concluir que:
Os trabalhos desenvolvidos utilizam os materiais condutores mais conhecidos no mercado, como o Flectron e o Zelt;
A espessura do substrato não ultrapassa 6 mm. Para a melhor integração no vestuário, a maioria dos autores utiliza substratos entre 2 mm e 3 mm, como sugerido em [1];
Muitas antenas utilizam o fleece (malha polar) como substrato. A pesar da dificuldade de caracterização deste material pela grande quantidade de ar que este possui, é justamente por isso que ele apresenta um bom desempenho. Como já visto anteriormente o ar é um bom isolante elétrico.
Os substratos dielétricos mais utilizados, apesar de muitos autores não terem especificado sua composição, possuem um valor de constante dielétrica
r r = 1.5.
Simulação prática Foram simuladas duas antenas do tipo patch
microstrip, com diferentes substratos têxteis, utilizando o software CST Microwave Studio 2011.
As antenas foram desenhadas de forma a serem ressonantes em torno dos 2.45 GHz e englobar a banda ISM (Industrial, Scientific and Medical) entre 2.4 e 2.5 GHz. Esta largura de banda também serve de suporte aos serviços de WLAN (Wireless Local Area Network), Bluetooth, SRCS (Short Range Communication Systems 802.15.4), entre outros. Materiais utilizados
Foram selecionados dois diferentes materiais têxteis para o substrato dielétrico e um tecido condutor para o patch e o plano de massa. O critério de escolha dos materiais para substrato consistiu em preferir materiais compostos de fibras que interagem pouco com a humidade, poliéster e poliamida, de forma a minimizar os efeitos da humidade na antena. Consistiu ainda em preferir para substrato materiais estáveis dimensionalmente e homogéneos, de forma a facilitar a estabilização da antena real a integrar em vestuário. O critério de escolha dos materiais condutores consistiu em preferir materiais com elevada condutividade e muito finos. Nas tabelas 2 e 3, podemos analisar as diferentes especificações de cada um.
Tabela 2 Especificações do tecido condutor
Tecido condutor
TECIDO 1 Fornecedor: Less EMF Inc.
Nome Composição Resistividade elétrica
Espessura (mm)
Condutividade elétrica (S/m)
Zelt Tafetá 100% nylon
revestido com uma liga de
cobre e estanho
0,006 1,75x105
Tabela 3 Especificações dos tecidos dielétricos
Tecidos dielétricos
TECIDO A Fornecedor: OBER S/A
Nome Composição Permitividade Relativa
r)
Tangente de perda
Espessura (mm)
Feltro 100% poliéster
1,3 0,02 2
TECIDO B Fornecedor: Du Pont
Cordura
100% poliamida
de alta tenacidade
1,9 0,0098 0,5
Simulação da Antena 1
Esta primeira antena foi projetada utilizando como tecido condutor o tecido 1 (Zelt) e como substrato dielétrico o tecido A (feltro de poliéster).
A alimentação da antena é feita com base em cabo coaxial e o ponto de alimentação está indicado pela marca vermelha. Este foi escolhido, por forma a conseguir o melhor ponto de adaptação da impedância
Na figura 1 podemos observar o design e na tabela 4
as dimensões obtidas através da simulação.
Figura 1 Esquema da antena 1. [fonte: autor]
Tabela 4 - Dimensões da antena 1. [fonte: autor]
Parâmetro Dimensão [mm] W, L 49.5, 50.0 Wgnd, Lgnd 100.0, 100.0 Fx, Fy 38.5, 50.0
Analisando a figura 2, podemos verificar a resposta
da impedância da antena simulada com a variação da frequência, assim constatamos que existe uma frequência de ressonância em torno dos 2.45 GHz, tal como se pretendia.
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Figura 2 Perdas de retorno (S11) simuladas para a antena 1.
[fonte: autor]
De acordo com a resposta obtida para o parâmetro
S11 a largura de banda obtida para este tipo de antenas é bastante estreita, estando contida entre 2.4 GHz e 2.5 GHz, o que cumpre com os requisitos propostos mas com margem muito pequena para eventuais desvios de um protótipo real.
Na figura 3 podemos observar a simulação do diagrama da radiação em uma versão 3D, onde é possível verificar que o máximo de propagação da radiação (indicado com cor vermelha) está no sentido do patch e um mínimo de radiação (indicado com cor azul) está no sentido de plano de massa.
Figura 3 Diagrama de radiação simulado da antena 1, (a) 3D, (b) 2D.
(a) (b)
Pela simulação, a antena 1 apresentou um ganho
satisfatório, sendo este 5.63 dB, o que é um valor elevado, na ordem de valores típicos de ganho obtidos para antenas impressas do tipo patch microstrip.
Já a eficiência de radiação desta antena é aproximadamente 47%, sendo este um valor um pouco abaixo das eficiências típicas para este tipo de antenas. Simulação da Antena 2
Esta segunda antena foi projetada utilizando como tecido condutor o tecido 1 (Zelt) e como substrato dielétrico o tecido B (Cordura®). Na figura abaixo podemos visualizar o formato da antena resultante da simulação.
A alimentação desta antena também é feita com base em cabo coaxial e o ponto de alimentação está indicado pela marca vermelha, como na antena 1.
Na figura 5 podemos observar o design e na tabela 5 as dimensões obtidas através da simulação.
Figura 5 Esquema da antena 2. [fonte: autor]
Tabela 5 - Dimensões da antena 2. [fonte: autor]
Parâmetro Dimensão [mm] W, L 42.0, 20.0 Wgnd, Lgnd 80.0, 60.0 Fx, Fy 20.0, 30.0
A resposta em impedância desta antena vai ser
muito parecida com a obtida para o caso anterior, visto que foi desenhada por forma a obter-se a mesma frequência de ressonância e uma banda equivalente. Podemos observar estes resultados na figura 6, que mostra as respectivas perdas de retorno (S11) obtidas. Figura 6 Perdas de retorno (S11) simuladas para a antena 2.
[fonte: autor]
Confirmar-se o bom funcionamento desta antena
para o conjunto de frequências entre os 2.4 GHz e 2.5 GHz tal como aconteceu com a antena 1. Abaixo, o diagrama de radiação da antena 2, figura 7, é muito semelhante ao obtido para a antena 1, visto que ambas antenas são tipo patch microstrip. Uma característica interessante a observar aqui, é que a radiação no sentido do plano de massa no caso da antena 2 é inferior à da antena 1. Este fenómeno de maior atenuação da radiação nessa direção pode ser explicado pela maior proximidade entre o patch e o plano de massa, devido à menor espessura do substrato.
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Figura 3 Diagrama de radiação simulado da antena 1, (a) 3D, (b) 2D.
(a) (b)
Esta antena, através da simulação apresentou um
ganho correspondente a -6.1 dB, que é um valor bastante baixo para este tipo de antena. Esse resultado é reflexo duma eficiência de radiação extremamente baixa com um valor em torno dos 6%. Conclusões
Podemos concluir que a antena 1, mostrou um ganho muito maior que a antena 2 mas, no que diz respeito a largura de banda, mesmo o substrato da antena 2 sendo bem mais fino que o substrato da antena 1, a diferença na permitividade relativa dos mesmos, acabou por fazer com que se conseguisse uma largura de banda bastante semelhante entre as duas.
Além disso, estas antenas apresentam boas dimensões espaciais para a integração no vestuário. Sendo antenas de dimensões pequenas, a antena 1 tem 10x10 cm2 e a antena 2 tem 8x6 cm2, e ambas sendo finas, podem ser colocadas em diversas partes do corpo, geralmente as costas por terem uma maior extensão plana, são normalmente o local mais visado. Referências [1] C. Hertleer, H. Rogier, S. Member, L.
for Off-Body Communication Integrated Into Protective IEEE Transactions on
Antennas and Propagation, vol. 57, no. 4, pp. 919 925, 2009. [2] I. Locher, M. Klemm, T. Kirstein, and G.
IEEE Transactions on Advanced Packaging, vol. 29, no. 4, pp. 777 788, 2006. [3] B. Grupta, S. Sankaralingam, and S. Dhar,
of Wearable and Implantable Antennas IEEE Conference
Publications, pp. 251 267, 2010. [4] S. Brebels, J. Ryckaert, C. Boris, S. Donnay,
IEEE Transactions on Advanced Packaging, vol. 27, no. 2, pp. 341 351, 2004. [5] P. Salonen, M. Keskilammi, J. Rantanen, L.
IEEE Conference Publications, vol. 2, pp. 789-794, 2001. [6]
IEEE Conference Publications, vol. 2, pp. 100-103, 2003. [7] P. Salonen, Y. Rahmat-Samii, M. Schafhth,
Antenna IEEE Conference Publicatons, vol. 1, June, pp. 459-462, 2004. [8] A. Tronquo, H. Rogier, C. Hertleer, and L.
IEEE Conference Publications, October, 2006. [9] S. Zhu and R. Langley -Band Wearable
Electronic Letters, vol. 43, no. 3, 2007.
Agradecimentos
Os autores agradecem ao FCT/MCTES pelo financiamento do projeto PTDC/EEA-TEL/ 122681/2010 - PROENERGY-WSN - Prototypes for Efficient Energy Self-Sustainable Wireless Sensor Networks
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Sesquiterpenes from Croton gratissimus
L.I.N. Canelo1, I. Mafuca2, A.R. Estebainha1, D.I. Mendonça1, R.S. Mata2
1Unidade de Materiais Têxteis e Papeleiros, Universidade da Beira Interior (UBI), Covilhã, Portugal; 2Chemistry
Department, Science Faculty, Agustinho Neto University, Luanda, Angola
Introduction The great biodiversity in the tropical forests, savannahs, and velds environments of Africa has provided indigenous cultures with a diverse range of plants and as a consequence a wealth of traditional knowledge about the use of the plants for medicinal purposes [1]. Croton is a genus of Euphorbiaceae comprising around 1,300 species, widespread in tropical regions of the Old and New Worlds. Several species have a long role in the traditional use of medicinal plants in Africa, Asia and South America. Popular uses include treatment of cancer, constipation, diabetes, digestive problems, dysentery, external wounds, fever, hypercholesterolemia, hypertension, inflammation, intestinal worms, malaria, pain, ulcers and weight-loss [2]. Croton gratissimus Burch. is represented by two varieties, the typical one (C. gratissimus Burch. var. gratissimus) being the subject of this study. This semi-deciduous tree species is widespread in sub-Saharan Africa, occurring on stony or rocky hillsides throughout much of the warmer and drier regions, from South Africa northeastwards to the horn of Africa [3,4]. Part of our study focuses on the purification and isolation of compounds from aerial parts of Croton gratissimus. Powdered aerial parts were extracted with methanol, the methanolic extract was fractioned in hexane, chloroform, ethyl acetate and aqueous fractions. The hexane fraction was rechromatographed and afforded ent-germacra-4(15),5,10(14)-trien-1 -ol (1), ent-kaur-16-en-18-ol (2); 7 -methoxyopposit-4(15)-en-1 -ol (3), 15-methoxy-neo-
clerodan-3,13-dien-16,15-olide-18-oic acid (4), kaur-16-en-19-oic acid (5), labda-8(17),12,14-trien-18-oic acid (6), -sitosterol (7), caryophyllene oxide (8) and spathulenol (9). From the chloroform fraction 7 -methoxyopposit-4(15)-en-1 -ol (10) was isolated. Their structures were established by means of IR spectroscopy, 1D and 2D NMR spectroscopy. Acknowledgements This work was partially funded by the project FCOMP-01-0124-FEDER-007430 (under COMPETE with FEDER funding) of Fundação para a Ciência e Tecnologia (FCT) and the Textile and Paper Materials Center.
References
[1] Simon, J. E.;, Koroch, A. R.;, Acquaye, D.;, Juliani, E. J. R.;, Govindasamy. R.. 2007. Medicinal Crops of Africa. Botanicals and Medicinals, pp. 322-331. [2] Salatino, A.;, Maria L. F. S.;, Giuseppina N. 2007. Traditional uses, Chemistry and Pharmacology of Croton species (Euphorbiaceae). J. Braz. Chem. Soc., Vol. 18, No. 1, pp. 11-33. [3] Mulholland, D. A.;, Moses, K. L.;, Neil, R. C.;, Helen, M. C.;, Emily, M. M.;, Jean-Marc, N. 2010. Cembranolides from the stem bark of the southern African medicinal plant, (Euphorbiaceae). Phytochemistry, vol. 71, pp. 1381-1386. [4] Langat, M. K..;, Neil, R. C.;, Peter, J. S.;, Dulcie A. M.. 2011. Cembranolides from the Leaves of Croton gratissimus. Journal of Natural Products, vol. 74, pp. 2349-2355.
17
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89
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OMe
O
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Figure 1 – Isolated compounds in Croton gratissimus
137
Covalent and non-covalent strategies for surface modification of different textile materials with antimicrobial properties
F Nogueira1,4, P Teixeira2, E Piskin3, I Gouveia4
1CICS-UBI Health Sciences Research Centre, University of Beira Interior
2Institute for Biotechnology and Bioengineering (IBB)
3Center for Bioengineering and Biyomedtek, Hacettepe University (Ankara, Turkey)
4R&D Unit Textile and Paper Materials, University of Beira Interior
Abstract New advances have been released in textile industry. Contributions at the level of textile fiber chains engineering has allowed modification of their structure, production of smart polymers responding to changes in environment, and attachment or entrapment of cells and bioactive molecules. Likewise, our society high demand of hygienic patterns, has increased the intensive research and development of antimicrobial textiles. Applications are being extended to underwear, sportswear, home furnishing, protective clothes, wound-dressings and in areas with high risk of microbial infection, as hospitals, schools and hotels. Biomedical products will probably be the largest application of antimicrobial textiles. During this work, antimicrobial peptides (AMPs) will be immobilized on textiles, in order to find if textile imobilized-AMP can attract and kill bacteria.
Introduction
Throughout last decades hospitals have faced tough challenges regarding growing microbial multi-resistance, especially in immunodepressed patients. The development of antimicrobial textiles appears as a promissing solution to decrease nosocomial infections. Some compounds have already been tested in textiles, such as Quaternary Ammonium Compounds, Biguanidines, Silver, Triclosan, etc. However, they proved to be limited. They showed reduced spectrum of microbial inhibition, which cause resistances, cytotoxicity causing skin irritation, toxicity to the environment, and gradually lose their bioactivity with use and launderings (1,2).
Antimicrobial peptides (AMPs) appear as an alternative to antibiotics. They are small, amphipathic, strongly cationic which bind to negatively charged phospholipid headgroups of microbial membranes;
microorganisms hardly develop resistance, otherwise they would have to change all their lipidic composition and/or organization; broad-spectrum antimicrobial activity. Although the mechanism of AMPs-microbial killing is still not known, many hypotheses have arisen: (i) membrane depolarization; (ii) formation of physical holes at the membrane; (iii) programmed bacterial death processes; (iv) phospholipidic redistribution; (v) internalization of the AMP (3). Natural polymers show few adverse reactions, excelent humidity control, biocompatibility and low-allergic responses, due to their similarity to macromolecules which biological environment is prepared to recognize and to deal with metabolically. Cellulose (cotton and bamboo), silk and other natural polymers show potential for wound dressings (4, 5).
Materials and Methods Preparation of (AMP)-textiles - A.1. Selection and characterization of textiles; A.2. Selection of AMPs; A.3. Evaluation of minimal inhibitory concentration (MIC) of AMPs and cytotoxicity studies Functionalization Strategies - A.4. Covalent functionalization by Chemical Reactions and Plasma Treatment; A.5. Non-covalent functionalization Textiles characterization - B.1. Mechanical Testing; B.2. Durable effect; B.3. Immobilization of AMPs Antimicrobial activity of functionalized textiles and mechanism of action of AMPs - C.1. Evaluation of the degree of antimicrobial effect of functionalized textiles; C.2. Study of mechanisms of AMPs action
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Results and Discussion For preliminary studies in order to optimise experimental conditions, L-Cys was used, instead of AMPs. L-Cys is cheaper and it has also some antimicrobial properties,
when compared with AMPs. L-Cys surface-linkage increased as the concentration of surface activator increased. Fig. 1. This chemical mechanism may be suitable for introducing the desired modifications in cellulose. Furthermore, functionalized samples were washed. Fig. 2. L-Cys remained attached on cotton surface after different washings. Thus, biocide applied to cellulose may prolong its activity after use and lauderings. L-Cys also showed antibacterial activity against Klebsiella pneumoniae strains (50 mg/ml) and Staphylococcus aureus (25mg/ml).
Figure 2. Washing cycle assays with L-Cysteine at 7.5%. L-Cys remained linked to cotton after different washings. Energy-dispersive X-ray spectroscopy.
References
1. Fischbach LA, Goodman KJ, Feldman M, Aragaki C. Sources of variation of Helicobacter pylori treatment success in adults worldwide: a meta-analysis. International journal of epidemiology. [Meta-Analysis Research Support, Non-U.S. Gov't]. 2002 Feb;31(1):128-39. 2. Gabbay Ba. Biocidal textiles can help fight nosocomial infections. Medical Hypotheses. 2008;70:990 4. 3. Costa F, Carvalho IF, Montelaro RC, Gomes P, Martins MCL. Covalent immobilization of antimicrobial peptides (AMPs) onto biomaterial surfaces. Acta Biomaterialia. 2011 Apr;7(4):1431-40. 4. Singh R JA, Panwar S, Gupta D and Khare SK. Antimicrobial activity of some natural dyes. Dyes and Pigments. 2005;66:99-102. 5. Ratner B. Biomaterials Science An Introduction to Materials in Medicine 2nd Edition2004.
Acknowledgements
This project is inserted in the scientific scope of the funded FCT project (PTDC/EBB-BIO/113671/2009)
Figure 1. Assays with two concentrations of L-Cysteine, 5% and 7.5%. Furthermore, different concentrations of cellulose activator-surface were used for each L-Cys concentration. Energy-dispersive X-ray spectroscopy.
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Malharia Funcional no s
A. L. Olivete, M. J. Geraldes 1UBI Universidade da Beira Interior
Resumo
O presente artigo visa desenvolver um body para bebês com atributos de um referido tema através de estruturas e tecnologia inovadora ao nível dos materiais têxteis e suas construções. O body apresenta um sistema de camadas conjugadas de dois materiais diferentes, o poliéster (hidrofóbico) e algodão (hidrofílico) que evita que a umidade, que porventura vaze da fralda, fique em contato com a pele do bebê.
Introdução
Este trabalho visa o desenvolvimento de um produto em malha, concebida especificamente para o mesmo, que contemple design e funcionalidade, muito particularmente no que diz respeito ao escoamento rápido da umidade. Para tal, selecionaram-se os materiais têxteis em função da funcionalidade pretendida e da sua adequação ao uso, sendo a estrutura de malha desenvolvida com o auxílio do suporte informático do sistema CAD fabricado pela Shima Seiki.
É um projeto multidisciplinar, que se desenvolveu no âmbito das unidades curriculares do curso de Mestrado em Design de Moda da Universidade da Beira Interior, como a disciplina Projeto de Design de Moda I, onde se desenvolveu a coleção, Design e Desenvolvimento de Tecidos, onde se criou uma coleção de tecidos e Marketing e Comunicação de Moda, onde se elaborou o plano de Marketing e Comunicação da Marca e Design e Desenvolvimento de Malhas onde se desenvolveram as estruturas de malha.
É um produto destinado ao universo infantil, sendo a coleção desenvolvida com foco na apresentação da marca Amigo Imaginário ao mercado virtual, com lançamento de um site de vendas, e cuja sua primeira coleção
-Movie -
produto inovador no mer
Apresentação da marca
A marca Amigo Imaginário, trabalha com o segmento infantil, oferecendo produtos de excelente qualidade, acabamento diferenciado (incita novas descobertas), manipulações de superfície (estimula o tato), ludicidade (proporciona diversão) e criatividade (favorece o
maior a capacidade de fantasiar, dado que a vida dos
adultos, e até das crianças, é uma eterna rotina, o papel da imaginação é quebrar essa rotina.
Com o passar dos anos e o advento de novas tecnologias e meios de vida, onde a criança é estimulada a pensar cada vez menos, a imaginação e a fantasia retomam sua importância. O propósito da marca é manter esse conceito sempre vivo, adotando o estilo de infância clássico, do qual as bases nunca vão mudar, crianças serão sempre crianças.
Segundo Isabela Breschiliare Piffer, no site Goinews:
crianças de 2 a 5 anos de idade. O objetivo da criação de tal amigo é auxiliar o desenvolvimento, a compreensão de fatos e a elaboração de sentimentos que ocorrem em diferentes situações, funcionando como refúgio ou ainda uma válvula de escape. Crianças que possuem um amigo imaginário geralmente são mais inteligentes, pois ele acaba por influenciar o seu desenvolvimento, e elas também possuem mais "conteúdo místico" em seus sonhos. Assim, as suas imaginações fantasiosas são mais ricas do que das crianças que não p2011)
Desenvolvimento do Projeto
- Público Alvo
- Consumidor
Podem-se considerar os pais como o público comprador, que precisam ser cativados por elementos diferenciados dos que já existem no mercado e que justifiquem a compra do produtos. Portanto, são jovens profissionais das mais diversas áreas, mas com boa sensibilidade artística, de personalidade inovadora e dinâmica e que procuram reunir nas suas escolhas ultramoderno e vintage; são pais dedicados, que sempre pensam numa estrutura familiar; gostam de arte, cinema e teatro em
ão moradores dos grandes centros urbanos mas passam bons momentos de descanso em ambientes bucólicos e naturais; possuem uma boa estabilidade financeira para viagens, compras de tecnologia e novidades do mercado.
- Usuário
Considera-se a criança, que escolhe o produto pelos aspectos visual e atrativo. São meninas, de 0 (zero) a
140
5 (cinco) anos de idade. Ativas, criativas e gostam do universo das cores; compartilham momentos com os pais em teatros, cinemas e parques ao ar livre; se entretêm com a tecnologia, mas participam muito de brincadeiras mais dinâmicas, da época dos seus pais; são bem educados e sabem se comportar em restaurantes, viagens e sempre que necessário; gostam de surpresa e querem isso também nas roupas e, ao brincar, criam mundos imaginários para movimentar seus momentos divertidos.
- Caracterização da Coleção
A coleção Zummm....., da marca Amigo Imaginário, traz
dentro de uma colmeia, com todos os segredos escondidos para a produção do mel. Assim como a colmeia, a coleção traz surpresas escondidas nos pequenos detalhes.
As estampas são geométricas e coloridas, aparecendo geralmente na parte interna dos looks, como nos forros e nos bodies, fazem alusão aos favos da colmeia, as plantas e as flores polinizadas pelas abelhas. As malhas e tecidos são produzidos com diferentes texturas de fios e de estruturas criadas para evidenciar e se aproximarem desse mundo.
Suas formas são rígidas, estruturadas e com elementos orgânicos, que se referem à vida regrada e organizada das abelhas na produção do mel e implementação da colmeia, tal como uma grande empresa a funcionar. As peças apresentam uma construção versátil, estruturada em camadas que apresentam detalhes escondidos com interferências na superfície dos tecidos, evidenciando a estrutura dos favos de mel. São peças que permitem modificações e transformações, levando a criança ao exercício do imaginário e da coordenação motora, com elementos estrategicamente posicionados para a fácil manipulação da criança.
É uma coleção dinâmica, mágica e envolvente, capaz de levar a criança a descobrir e criar novos mundos possíveis, representadas nas figuras 1 e 2.
Figura 1 - Imagem conceito da coleção
Figura 2 - Coleção completa
- Apresentação do Produto
A marca Amigo Imaginário propõe ao mercado uma inovadora tecnologia na construção da malha por trama usada na confecção dos bodies.
O Body apresenta, portanto, dois tipos de malha e materiais têxteis: na parte superior, da cintura até a gola, é confeccionado com o mais puro algodão orgânico, que não agride a pele delicada do bebê e possui três estruturas distintas, representadas na figura 3, para diferenciar o body; na parte inferior é confeccionado com uma malha dupla, formado, por duas camadas de fibras diferentes, continuando o mesmo algodão orgânico na camada exterior, porém, a camada interior apresenta barreiras de poliéster reciclado, obtido a partir da reciclagem de garrafas P.E.T., que, por ser hidrofóbico, facilita o transporte da umidade que vazou da fralda para o lado externo, mantendo o bebê sequinho e protegido. (GERALDES, 2000)
Figura 3 - Três estruturas distintas de malha
- Desenvolvimento Experimental
Criar um body, que tenha uma funcionalidade incorporada, ou seja, que responda às necessidades dos bebês em relação ao excesso de xixi, que em alguns casos vaza da fralda durante o uso.
A ideia principal é fazer uma estrutura de malha, com duas camadas distintas e separadas, na região da fralda, onde a camada interior, que estará em contato com a fralda, seja de poliéster e uma segunda camada, que fica para o lado externo da peça, é feita de algodão.
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O poliéster, hidrofóbico (possui um regain de aprox. 0,4%) e com uma malha mais aberta, funciona como uma camada de separação, ou seja, o algodão da camada externa hidrofílica (possui um regain de aprox. 9%) 'suga' a umidade para o lado de fora da peça, evitando que a pele do bebê fique úmida. Como referido, o poliéster utilizado foi desenvolvido através da reciclagem de garrafas P.E.T., inserindo um outro conceito, o conceito de responsabilidade socioambiental. É apresentado na cor branca, em todas as cores de peças, para não necessitar de tingimento sintético e consequente agressão ao ambiente. (FONSECA, 2005)
O algodão, também ambientalmente responsável, é orgânico, produzido sem o uso de pesticidas agressivos ao meio ambiente e tinto com corantes naturais da flora e fauna brasileira (figura 4). (FERREIRA, 1997)
Esses corantes utilizados nos obtenção das diferentes cores, foram:
Cor vermelha: extraído do inseto cochonilha
Cor laranja: extraído do fruto da catuaba ou da semente do urucum
Cor amarela: extraído das folhas da quaresminha do campo
Cor marrom: extraído dos frutos do pinhão ou das sementes da romã
Cor verde: extraído dos brotos da alfafa
Figura 4 - Matéria prima e cores resultantes
Fonte: www.tingimentonatural.blogspot.com
- Sistema CAD
O Sistema CAD (Computer-Aided Design, ou em português, desenho assistido por computador) utilizado é o da Shima Seiki, e trata-se de um suporte informático utilizado para criação e design de malhas por trama, permitindo a criação de padrões de diferentes estruturas e sua preparação para a tricotagem como: os códigos de ação das máquinas, número de pontos, seleção dos guia-fios, códigos de repetições, entre outros fatores que proporcionam o melhor resultado na aplicação têxtil dos materiais envolvidos.
É um sistema que melhora consideravelmente a eficiência e qualidade da produção, desde a sua base de dados, onde ficam armazenados todos os projetos desenvolvidos para possível utilização futura, assim como a sua ligação com os teares (máquinas de tricotagem) e o seu exigente padrão de qualidade e confiabilidade técnica, planejamento, produtividade, facilidade de uso, custo/desempenho e avaliação da produção.
- Desenvolvimento das estruturas de malha
Outro passo importante, foi criar uma malha que conseguisse transmitir a ideia dos favos de mel, inserindo não só mudança de pontos como também evidenciar um grande relevo na malha. Foram criadas três estruturas distintas de malha, sendo dois deles de construção mais simples, mais acertada e sem maiores problemas na
execução. Já o terceiro foi mais complexo e o que exigiu mais testes.
- Experimentos
O desenvolvimento das estruturas de malha utilizadas na caracterização deste projeto, passou por diversas fases, representadas pelos itens a seguir, que determinaram o resultado final, nomeadamente:
executadas apenas com alternância de pontos jérsei ao avesso, jérsei ao direito e ponto pérola, porém os efeitos pretendidos não ficaram muito evidentes.
e começou a ficar mais evidente o relevo, porém o desenho não ficou com forma de um hexágono ou octógono que era o efeito pretendido inicialmente.
em algo parecido a um quadrado.
necessidade de evidenciar o relevo ainda era um objetivo a ser atingido.
-se o fundo na esperança que o relevo se pronunciasse um pouco mais, mas não se atingiram as expectativas.
-se em fio mais fino.
-se, consequentemente, o espaço entre os hexágonos, invertendo o jérsei para o avesso. O resultado ainda não foi satisfatório.
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totalmente as expectativas, mas optou-se por uma das alterações.
Embora no início, a programação apresentasse problemas e a malha dupla não ficasse ligada.
-se a malha e as camadas ficaram interligadas.
poliéster, ficou frágil, e cresceu muito mais que a malha de algodão. Porém, novos testes foram iniciados.
Finalmente, colocaram-se alguns pontos de ligação entre a malha de algodão e a malha de poliéster, em desenhos que se assemelhassem à colmeia também e assim a malha de poliéster ficaria mais estável e não ficaria em excesso.
- Produto
O produto final desenvolvido é o que a seguir se apresenta na figura 5:
Figura 5 - Peça confeccionada, visão das duas diferentes malhas.
Considerações Finais
O objetivo deste trabalho foi criar um produto inovador no mercado que pudesse ter um apelo funcional, sustentável e estético equilibrados. Para cada um dos objetivos foram traçadas formas e procedimentos que contribuíssem para o resultado final satisfatório, desde a escolha da temática, das estruturas, dos materiais e das suas funções, reunidos num produto que, em sua confecção, não fosse agressivo à natureza e que carregasse uma forte carga de componentes sustentáveis do início ao fim da cadeia produtiva.
Os custos e a sua produção industrial não foram avaliadas, ficando, portanto em aberto espaço a novas pesquisas no âmbito da sua construção com malhas diferenciadas, com recurso ao processo seamless (sem costuras) e com outros materiais que lhe confiram ainda outras funcionalidades.
Referências
1. Associação Brasileira de Químicos e Coloristas Têxteis, Manual Técnico de Poliéster. [Online]. Avaliable at http://www.abqct.com.br/artigost/Manual%20de%20Poliester.pdf [Accessed 25 March 2012]
2. FERREIRA, Eber Lopes. Corantes Naturais da Flora Brasileira - Guia Prático de Tingimento com Plantas. São Paulo: 1997.
3. FONSECA, Ruben Guilherme da. Hidrofilidade em Fibras de Algodão Branco e Naturalmente Colorido. V Congresso Brasileiro de Algodão, 2005. [Online]. Avaliable at http://www.cnpa.embrapa.br/produtos/algodao/publicacoes/trabalhos_cba5/491.pdf [Accessed 25 March 2012]
4. Fundação Nacional Pró-Memória Brasil. A Tecelagem Manual no Triângulo Mineiro uma Abordagem Tecnológica. SPHAN, Brasília: 1984.
5. GERALDES, Maria José de Oliveira. Análise experimental no Conforto Térmico das malhas funcionais no estado úmido, Tese dout. Eng. Têxtil, Univ. Minho, Braga:2000.
6. Psicologia, 2011. Seu filho tem um amigo imaginário?. [Online] (Updated 27 April 2011). Available at http://www.goionews.com.br/?Conteudo=news&id_noticia=16928&id_edicao=1114 [Accessed 25 April 2012]
7. Shima Seiki, Products. [Online]. Avaliable at http://www.shimaseiki.com/product/knit/ [Accessed 20 January 2012]
8. Tingimento Natural, 2009. Tingimento Natural. [Online] (Updated 2010). Available at http://tingimentonatural.blogspot.com/search/label/ [Accessed 24 March 2012]
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Epoxidação do Guaiol e seus derivados
Sofia Pombal1, Jesus Rodilla1, Lúcia Silva1
1 Unidade de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, Rua Marquês d’Ávila e Bolama, 6200 Covilhã.
Abstract
Os substratos utilizados neste trabalho obtiveram-se a partir do tratamento cromatográfico da essência cristalizada de Bulnesia sarmientoi, e são o guaiol (1), o bulnesol (2) e α-guaieno (3).
Tratando estes compostos para que ocorresse a reacção de hidroboração e de epoxidação, verificamos que os produtos obtidos eram epóxidos, ou seja, os produtos de partida devido à sua reactividade não sofrem a reacção de hidroboração, sofrendo apenas reacção de epoxidação.
Introdução
A Bulnesia sarmientoi é uma planta nativa da região da Argentina e Paraguai. O seu óleo é o Guaic. Este é obtido das aparas de madeira da planta através de uma destilação a vapor. Este óleo pode ser usado como ingrediente de perfumes e usos medicinais externos. Este tem uma grande actividade repelente sobre os pulgões, nomeadamente a duas espécies testadas (Myzus persicae e Rhodalosiphum padi) [1].
O óleo essencial apresentou uma actividade anti – fúngica muito boa frente às três espécies de Fusarium testadas, sendo o F. solani e o F. moniliforme os mais sensíveis. Nem o óleo nem os seus componentes maioritários foram fitotóxicos frente a Lacuna sativa.
O Guaiol e o Bulnesol são álcoois terciários que reagem facilmente mas em contrapartida têm um processo de acetilação bastante débil em condições de temperatura elevada e meio ácido.
Método experimental:
Epoxidação com MPCBA: Dissolver 2 g (9,8 mmol) de α-guaieno em diclorometano (25 mL), colocar em banho de gelo e adicionar MPCBA 2,25 g (9,8 mmol), aguardar 24horas. Lavar com NaHCO3 10% e decantar. Cromatografiar.
Hidroboração com BBN2.THF: Dissolver 0,6 g (2,7mmol) de α-guaieno em tetrahidrofurano, colocar em banho de gelo e adicionar BBN2.THF aguardar 13 dias e adicionar 20 mL de NaOH 4% e e 2,5 mmol de peroxido de hidrogénio e colocar em refluxo durante 2 horas. Lavar e cromatografiar.
Hidroboração com geranyl bromide: Dissolver 0,5 g (0,25mmol) de α-guaieno em tetrahidrofurano, adicionar 2,7 mmol de n-BuLi e colocar em banho de gelo durante 20 minutos. Adicionar 0,25 mmol de geranyl bromide. Lavar e secar este produto. Dissolver o produto obtido (0,137 g, 0,62 mmol) em Tetrahidrofurano e adicionar 0,62mmol de NaH e colocar em banho de gelo durante 30 minutos.
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Adicionar 0,62 mmol de geranyl bromide. Lavar com NH4Cl (sat) e cromatografiar.
Hidroboração com disiamylborane[2]: Dissolver 0,1 g (0,48 mmol) de α-guaieno em tetrahidrofurano e colocar em banho de gelo, adicionar a disiamylborane. Aguardar 1h 30 min. Adicionar 252 mmol de peroxido de hidrogénio, 21 mmol de NaOH 3N e 48,6 mmol de água. Colocar à temperatura ambiente durante uma hora. Seguidamente acetilar o produto reaccional com 1mL de piridina e 0,5 mL de anidrido acético durante 24 horas. Lavar e cromatografiar.
Resultados e discussão
Através da análise espectroscópica dos diversos produtos verificou-se a composição reaccional e as alterações ao longo desta.
Na epoxidação do α-guaieno com MPCBA formou-se o composto (4) com um rendimento de 6,75%, ou seja transformou a ligação dupla entre C11-C13 em epóxido.
Na hidroboração de α-guaieno com BBN2.THF obteve-se o composto (5) com um rendimento de 3,57%, como se pode verificar formou-se um epóxido que se formou entre as ligações duplas ligações que existiam no produto de partida, ou seja as ligações duplas dos C1-C5 e C11-C13 formaram um epóxido entre C5-C11.
Quando se fez reagir a mistura de guaiol e bulnesol com brometo de geranilo e n-ButLi obteve-se mais uma vez o composto (5) com um rendimento de 13%.
Numa nova tentativa de hidroboração de α-guaieno com a disiamylborane obteve-se o composto (6) com um rendimento de 14%, nesta reacção a alteração existente foi entre a ligação dupla que existia em C1-C5 formando nesse mesmo local o epóxido[3].
-
Referências
[1] J. M. Rodilla, L. M. Silva, N. Martinez, D. Lorenzo, D. Davyt, L. Castillo, C. Giménez, R. Cabrera, A. González – Coloma, J. Zrostliková, E. Delacassa, “Advances in the identification and agrochemical importance of sesquiterpenoids from Bulnesia sarmientoi essencial oils”; Industrial Crops and Products 33, 497-503, 2011. [2]J. A. Marshall, R. A. Ruden, “Selective degradation of guaiol. The synthesis of 7-
epiguaiol”, Journal of Organic Chemistry, 36-17, 2569-2571, 1971
[3] V. H. Kapadia, V. G. Naik, M. S. Wadie and Sukh Cev National Chemical Laboratory, Poona (India), “Sesquiterpenoids from the essential oil of Cyperus Rotundus”, Tetrahedron Letters, 47, 4661-4667, 1967.
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Trihalomethanes formation in treated wastewaters
A.S. Rebelo1, M.I.A. Ferra2, R. Oliveira2, A. Marques2, I. Gonçalves2 1Ag. Port. Ambiente – A.R.H. Algarve, 2Chemistry Department, University of Beira Interior, 6201-001 Covilhã
Abstract
Although chlorine has been widely used in water disinfection, it may lead to by-products formation, such as trihalomethanes (THM) and haloacetic acids which may be harmful to human health. Chlorination techniques have been currently applied in treated wastewaters for reuse since it is necessary a residual disinfection potential to prevent recontamination during storage. After the addition of sodium hypochlorite, THM formation in a synthetic wastewater, with characteristics identical to those of treated effluents from some wastewater treatment plants, against the reaction time was studied. Chloroform was the only quantifiable trihalomethane. It increased sharply in the first hour of contact time and only a slight increase after that time was observed. Dissolved organic carbon and absorbance values at 254 nm decreased more rapidly also in the first hour of reaction.
Introduction Water disinfection is essential to reduce waterborne pathogens and to ensure safe water supply to population. However, the chemical disinfection may lead to the formation of by-products potentially harmful for human health. Chlorine has been widely used in water disinfection for multiple purposes: drinking, recreational and wastewaters. The use of chlorination techniques in treated wastewaters is particularly important for reuse trials, due to the need of a residual disinfection potential to prevent recontamination during storage. Over the last thirty years, many investigations have been made on the formation of chlorination by-products, namely trihalomethanes and haloacetic acids [1]. Classical trihalomethanes (THM) consist of chloroform (CHCl3), dichlorobromoform (CHCl2Br), dibromochloroform (CHBr2Cl) and bromoform (CHBr3). They are formed from the reactions of hypochlorous acid (HOCl) with natural organic matter [2]. The chloroform was identified as a priority substance according to the Water Framework Directive, i.e., it is considered a substance that presents a significant risk to or via the aquatic environment [3,4]. This work presents a study on trihalomethanes formation in wastewaters with characteristics identical to those of some treated wastewaters from treatment plants located in Algarve’s region.
Materials and Methods Several wastewater samples with different composition were prepared in the laboratory in order to attain similar characteristics to some treated effluents from wastewater treatment plants. Tables I and II give the composition and characteristics, respectively, of a selected sample for which water collected from a garden pond was used as solvent, after filtration.
Table I. Composition of synthetic wastewater
Peptone
5 mg L-1
Yeast extract
25 mg L-1
KH2PO4
184 mg L-1
K2HPO4
43.5 mg L-1
Na2HPO4.H2O
53 mg L-1
NH4Cl 30 mg L-1
Table II. Characteristics of synthetic wastewater
Chemical oxygen demand
80 mg L-1 (O2)
Dissolved organic carbon
20.3 mg L-1
Nitrogen (ammonia)
8.9 mg L-1
Nitrogen (Kjeldahl)
9.3 mg L-1
Uv absorbance (254 nm)
0.184
Specific uv absorbance
0.906 L mg-1 m-1
pH 7.0
For the chlorination, 0.8 mL of a sodium hypochlorite solution (NaOCl) with 13 % active chlorine were added to 200 mL of the effluent in each of seven flasks and put in a thermostated water bath, Grant, model LTD 20, at 25 0.05 ºC. Another sample with no added NaOCl was used as blank. After the contact times: 1, 15, 30, 60, 120, 180 and 330 minutes, the quenching agent (sodium thiosulphate) was added for depletion of residual chlorine and samples were collected for absorbance measurements, in a He ios spectrophotometer, determination of dissolved organic carbon (DOC) performed in a Shimadzu TOC-VCPH apparatus and trihalomethanes were determined by gas chromatography (GC-MS).
147
Results and Discussion As previously observed [5], in the chlorinated synthetic wastewaters only chloroform was quantifiable and the other three trihalomethanes were barely detected. Those results are consistent with the effluent composition since no brominated compounds were added. It is known there is a good correlation between THM formation potential and uv absorbance at 254 nm [6]. Figures 1, 2 and 3 show examples of the variation of uv absorbance, DOC and chloroform formation along the reaction time. As illustrated in figure 1, the solutions absorbance at 254 nm decreased more rapidly in the first hour of reaction but continues to decrease steadily along the time.
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0 100 200 300 400
reaction time / min
Abs
/ 25
4 nm
Figure 1. Absorbance at 254 nm against reaction time
The dissolved organic carbon shows a similar variation (figure 2), with a more pronounced decrease also in the first hour of reaction.
17.4017.6017.8018.0018.2018.4018.6018.8019.0019.20
0 100 200 300 400reaction time / min
DO
C /m
g L
-1
Figure 2. Variation of dissolved organic carbon with reaction
time Figure 3 illustrates the chloroform formation during the same period of time. It is quite fast in the first 50 minutes, with a slow increase after the first hour of contact time. The trihalomethanes formation is a complex reaction between chlorine and diverse organic matter, so its kinetic description is likely not to be a simple one. As previously discussed [2], the initial THM formation corresponds to the fast reacting THM precursors while the final THM formation corresponds to the total concentration of THM precursors.
020
4060
80100
120140
160
0 100 200 300 400reaction time / min
Clo
r /
g L-1
Figure 3. Chloroform formation from chlorination of
wastewater
Conclusions This study shows that trihalomethanes are formed in chlorinated synthetic wastewater, being the chloroform the dominant species. The chloroform formation along the reaction time seems to indicate the presence of fast reacting THM precursors as well as slowly reacting precursors in the organic matter. References 1. Liang, L., Singer, P.C., Environ. Sci. Technol., 37,
2920-2928, 2003. 2. Gallard, H. and Gunten, U., Water Research, 36, 65-
74, 2002. 3. European Commission, Directive 2000/60/EC of the
European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy, Off. J. Eur. Commun. L327, 1–72, 2000.
4. European Commission, Directive 2008/105/EC of the European Parliament and of the Council of 16 December 2008 on environmental quality standards in the field of water policy, Off. J. Eur. Commun. L348, 84-97, 2008.
5. Rebelo, A.S., Anágua, T.A., Ferra, M.I.A., Marques, A., Actas do Simpósio 2011: Transferência de Conhecimento e Tecnologia, UMTP, Univ.Beira Interior, 138, Dez. 2011.
6. Ates, N., Kitis, M., Yetis, U., Water Research, 41, 4139-4148, 2007.
Acknowledgements The authors gratefully acknowledge the financial support from the Research Unit UMTP, Fundação para a Ciência e Tecnologia (FCT), Portugal. The authors also thank the Portuguese Environment Agency, namely the Algarve River Basin District Administration, and Vanda Reis and Pedro Antunes from the Reference Laboratory, and are also grateful to Dr. A. Fernandes for the DOC analyses.
148
Phenolic compounds in cork processing wastewater
Diana Santos, Nicole Canto, Roberto Páscoa, Lúcia Silva, Rogério Simões, Arlindo Gomes
Unity of Textile & Paper Materials, University of Beira Interior, 6201-001- Covilhã
Abstract
Cork processing wastewaters samples were analyzed in terms of total phenolics and tannins content using the Makkar method and HPLC for specific compounds. We quantified total phenols and non-tannin content. Next, by subtracting non-tannin from total phenol we obtained the concentration of total-tannins. For the second method we selected four phenolic acids and three phenolic aldehydes, previously reported to be present in cork wastewater, optimize the conditions for the separation by HPLC for the analyze of raw samples, ultrafiltration concentrates and permeates, before and after chemical oxidation by ozone.
Introduction
Phenolic compounds are secondary metabolites widely distributed throughout the plant kingdom. There are approximately 8,000 naturally occurring compounds belong to this category, all of which share an aromatic ring bearing at least one hydroxyl subsistent in skeleton [1]. The term “plant phenolics” encompasses simple phenols, phenolic acids, coumarins, flavonoids, stilbenes, up to hydrolysable and condensed tannins. The naturally occurring phenolic acids contain two distinctive carbon frameworks: the hydroxycinnamic and hydroxybenzoic structures. Although the basic skeleton remains the same, the numbers and positions of the hydroxyl groups on the aromatic ring make the difference and establish the variety. The polyphenols, to which the flavonoids belong, possess at least two phenol subunits; compounds possessing three or more phenol subunits are referred as tannins.
The presence of phenolic compounds in wastewaters from agro-industries is a common occurrence, namely in olive mill and cork processing effluents. The presence of phenolic compounds is being correlated with the bio-recalcitrant nature of these effluents and contributes for the difficulties to achieve depuration according legal requirements.
The first stage of the cork industrial process is focused on the cleaning, disinfection and moistening of the raw material. For this purpose, the corkwood is immersed in boiling water up to one hour after being dried in open air from three to six months. Depending on the quality of raw material and type of product this processing water can be reuse from 6 up to 30 times. Therefore, phenolic content
is transferred and accumulates in the effluent, which presents a very low biodegradability restraining the possibility to accomplish depuration by biological processes.
In this preliminary study we quantified the total phenols and tannins content using the Makkar procedure [2]. We selected and established the conditions for HPLC analyze of low molecular weight phenols, which will be quantified to evaluate an integrated treatment process that includes membrane technologies and chemical oxidation by ozone.
Materials and Methods
Total Phenolic Compound Analysis.
The amount of total phenolics in cork wastewater was determined with the Folin-Ciocalteu reagent according to the method of Ainsworth and Gilliespie [3] using tannic acid as a standard. Samples (200 μL, three replicates) were introduced into test cuvettes, and then 1.0 mL of Folin-Ciocalteu’s reagent and 5.0 mL of Na2CO3 (20.0%) were added. The absorbance of all samples was measured at 765 nm using the Thermo Electron Corporation Helios gama UV-Vis spectrophotometer after incubating at 25 °C for 40 min. Results were expressed as acid tannic equivalent per litter.
Tannin Analysis.
Non-tannins phenol was estimated by precipitating tannins with polyvinyl polypyrrolidone (PVPP), which binds tannins. 200 mg PVPP was taken in test tube and then 2.0 mL distilled water and 2.0 mL tannins extract was added. Vortex it and kept for 15 minutes at 4ºC. Then the mixture was again vortex and filtered through Whatman filter paper No. 1. Filtrate was taken for estimation of non tannin phenol. 150 μL of filtrate was taken in test tube and volume was made to 1.0 mL with distilled water and then processed like that of total phenol estimation. Concentration of non tannin phenol was calculated from the standard curve. Total tannins were calculated by subtracting non tannin phenol from total phenol.
HPLC Analysis.
HPLC analysis were performed in a Perkin Elmer LC 101 chromatograph, with a Perkin Elmer LC 290 UV detector.
The sample was centrifuged and 100 μL aliquots were analyzed by HPLC. The sample used for HPLC analysis
149
was passed through a 0.45 μm filter before injection into a reverse phase Kromasil C18 column (250 � 10 mm i.d., particle size 5 μm). The mobile phase used was: A [H2O-H3PO4 (999:1)] and B [methanol-H3PO4 (999:1)]. The gradient profile was 0–5 min, 98% A; 5–10 min, 98–80% A; 10–12.5 min, 80% A; 12.5–20 min, 80–72% A; 20–30 min, 72% A; 30–35 min, 72–98% A; 35–45 min, 98% A. The flow rate was 2.0 mL/min and the temperature of the chromatographic oven set to 40 °C. Detection was carried out at 254 nm. The mobile phase was filtered through a microfilter of 0.45 μm.
The standard solutions used were: gallic acid 1, protocatechuic acid 2, protocatechuic aldehyde 3, caffeic acid 4, vaniline 5, ferulic acid 6 and coniferaldehyde 7.
OH
O
HO
HO
OH
OH
O
HO
HO
H
O
HO
HO
1 2 3
HO
HOOH
O
H
O
HO
H3CO
4 5
HO
H3COOH
O
HO
H3COH
O
6 7
Results and Discussion
In Figure 1 we present the results for calibration curve accordingly the procedure of Makkar [2].
The results for the quantification of the total phenols and tannins in the raw wastewater samples (RW) collected in one industry located in the Portalegre district are resumed in Table 1. These results are within those reported by other authors for gallic and tannic acid concentration. These authors also correlated the low biodegradability potential of cork processing wastewaters with the content of phenols.
We selected the phenols accordingly their previously reported presence and relevance in RW samples and accordingly their MW because the integrated treatment process includes ultrafiltration and/or nanofiltration stage to concentrate the pollutants for chemical oxidation with ozone, which intends to increase biodegradability.
y = 0.0811x - 0.0201R2 = 0.9888
0.000.050.100.150.200.250.300.350.40
0 1 2 3 4 5
mg of tannic acid/L
Abso
rban
ce a
t 765
nm
Figure 1. Standard curve of tannic acid
Table 1. Total phenols and tannins contents of cork wastewater.
Sample Total Phenols (mg /L)*
Tannins (mg/L)*
1 284 222 2 524 399 3 336 276 4 464 397
* mg of tannic acid;
The HPLC method was developed and optimized in order to achieve the best resolution of the maximum number of peaks of low molecular weight phenolic compounds present in samples, in the shortest analysis time. Several factors were studied namely the instrumental operating conditions (column, temperature, flow rate, injection volume and wavelength), the solvents, the elution program.
Using the optimized conditions, well-resolved chromatogram of standards was obtained after 16 min run (Figure 2).
Figure 2. Chromatogram of standard phenolic compounds detected at 254 nm.
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Peak identification is shown in Table 2.
Table 2 Retention time and identification of chromatographic peaks
tR (min) Compound Formula MW
(g/mol) 1 5.9 Gallic acid C7H6O5 170 2 6.5 Protocatechuic acid C7H6O4 154 3 7.8 Protocatechuic aldeyde C7H6O3 138 4 10.8 Caffeic acid C9H8O4 180 5 14.0 Vaniline C8H8O3 152 6 15.3 Ferulic acid C10H10O4 194 7 16.2 Coniferaldehyde C10H10O3 178
Conclusions
The concentration of total phenols and tannins in the RW varied from 284 to 524 mg of tannic acid/L and 222 to 399 mg of tannic acid/L, respectively. These results are within those previously reported by other authors.
This preliminary study of HPLC demonstrate the possibility to access the concentration of low MW phenols in RW samples, concentrates and permeates from ultrafiltration and nanofiltration, before and after chemical oxidation by ozone.
References
1. Croteau, R., Kutchan, T. M., Lewis, N. G., in: Buchanan, B., Gruissem, W., Jones, R. 2000, Biochemistry & Molecular Biology of Plants, American Society of Plant Physiologists, Rockville, MO 1250.
2. Makkar, H.P.S., Blummel, M., Borowy, N.K. and Becker, K. 1993 Gravimetric determination of tannins and their correlations with chemical and protein precipitation methods. J.Sci. Food Agric., 61, 161.
3. Ainsworth E.A. and Gillespie K.M.. 2007 Estimation of total phenolic content and other oxidation substrates in plant tissues using Folin-Ciocalteu reagent. Nat Protoc, 2(4), 857.
Acknowledgements
Thanks are due to FCT and FEDER for funding the Project (PTC/AGR-AAM/102042/2008.
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Antioxidant activity of extracts from leaves of Betula celtiberica
Ana Serra, Arlindo Gomes, Lúcia Silva
Unity of Textile & Paper Materials, University of Beira Interior, 6201-001- Covilhã
Abstract
The aim of this work was to study the antioxidant activity (AAI) of Betula celtiberica extracts, using the DPPH method. Leaves of B. celtiberica were collected in the Natural Park of Serra da Estrela. Five extracts of leaves were obtained by increasing polarity (Bc.l.1), an extract only with ethanol (Bc.l.2) and another extract with water (Bc.l.3).
The extracts obtained of n-hexane and dichloromethane showed no antioxidant activity in the range of concentrations studied DPPH. The extracts of ethyl acetate, ethanol and water present strong antioxidant activity. The antioxidant activity of methanol extract is very strong.
Introduction
Betula celtiberica, also known as birch, usually reaches the 20 meters tall and live up to 100 years. The stem is white and the crown is conical-pyramidal. Its leaves are ovate to triangular and flowering occurs from April to May. It is a closely related species to B. pendula and B. pubescens differing in many aspects, morphology and geographical distribution. The species is spontaneous in the mountains of Trás-os-Montes, Montesinho and Serra da Estrela in Portugal.
The free radical biology studies the formation and elimination of free radicals and the damage caused by free radicals in biological systems. It is very clear that reactive oxygen species (ROS) contribute to the pathology of many diseases, including atherogenesis, neurodegeneration, chronic inflammation, cancer and physiological senescence. Thus, the antioxidants are considered important due to their nutraceutical health benefits, many are widely used in the food industry as potential inhibitors of lipid peroxidation. However, it was demonstrated that the synthetic antioxidants may accumulate in the body, which can result in liver damage and carcinogenesis. These problems are not observed in natural antioxidants extracted from plants with high antioxidant activity.
1,1-diphenyl-2-picrylhydrazyl (DPPH), is a type of stable organic radical. The oxidative assay with DPPH is used
worldwide to quantify the ability to capture free radicals. The ability of compounds to remove the organic radical DPPH, can be expressed as its antioxidant activity. The solution DPPH is dark purple with an absorption peak at 517 nm, which disappears in the presence of radical scavenger of the reactive system, and when the odd electron in the DPPH nitrogen is paired. The reaction rate and capacity of radical scavenger and value depend on the rate of disappearance of the peak of DPPH. Compared to other methods, the DPPH assay has many advantages such as good stability, sensitivity, is reliable, simple and feasible.
The DPPH assay results have been presented in several ways. Most studies results expressed as IC50, defined as the amount of antioxidant required to reduce 50% of the initial concentration of DPPH.
The aim of this study was to study the antioxidant activity (AAI) of various extracts from leaves of Betula celtiberica collected in the Natural Park of Serra da Estrela at 1500 meters of height, using different concentrations of DPPH.
Materials and Methods
Plant Extract
Soxhlet extraction of crushed leaves of Betula celtiberica in increasing polarity (Bc.l.1) in the order of the following solvents: n-hexane, dichloromethane, ethyl acetate, ethanol and methanol. More extractions were performed following the same method, only with ethanol (Bc.l.2) and another one with water (Bc.l.3), collecting the aqueous extract. Antioxidant Activity
The antioxidant activity of the samples was determined by the method of antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH). From an initial solution of DPPH (0.2 mM) were prepared solutions with the following dilutions: 0.04 mM, 0.06 mM, 0.08 mM, 0.10 mM. These concentrations were selected because the range of linearity of DPPH.
For each extract were prepared solutions in methanol with the following concentrations ( g/mL): 0, 50, 100, 200, 250, 500, 1000, 1500.
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In performing the assay, add 0,1 L solution of the samples in different concentrations, 3.9 mL of a solution of DPPH. Tests were performed in triplicate. After an incubation period of 90 min at room temperature and in the dark, absorbance was measured at 517 nm. The inhibitory activity was calculated as follows:
where Abs0 is the absorbance of the blank and Abs1 is the absorbance in the presence of compound at different concentrations. The IC50 (concentration of the extract able to inhibit 50%) was calculated graphically with the concentration of the extract versus the corresponding inhibitory effect (% I). The antioxidant activity was expressed as the antioxidant activity index (AAI), calculated by:
Thus, the AAI was calculated considering the concentration of DPPH and the concentration of test compound in the reaction, resulting in a constant for each compound. For each plant extract is considered to have low antioxidant activity when AAI <0.5, moderate when AAI between 0.5 and 1.0, strong when AAI between 1.0 and 2.0, and very strong when AAI> 2.0. Assays were performed in triplicate and all samples DPPH solutions were prepared daily.
Results and Discussion
Table 1 - Values for IC50 ( g /mL) and antioxidant activity index (AAI) with different final concentrations of DPPH.
[DPPH]
mM
Bc.l.1 Ethyl acetate Bc.l.1 - Ethanol Bc.l.1 - Methanol Bc.l.2 - Ethanol Bc.l.3 - Aqueous
IC50 AAI IC50 AAI IC50 AAI IC50 AAI IC50 AAI
0,04 15,369 1,026 9,735 1,620 7,527 2,095 13,645 1,156 12,872 1,226
0,06 22,826 1,036 17,806 1,328 12,147 1,947 20,230 1,169 17,794 1,329
0,08 28,802 1,095 21,580 1,462 14,276 2,209 24,863 1,268 20,451 1,542
0,10 34,945 1,128 27,723 1,422 17,348 2,273 29,741 1,326 23,545 1,249
In the present study we evaluated the antioxidant activity of the extracts in increasing polarity (Bc.l.1), ethanol (Bc.l.2) and aqueous (Bc.l.3). Leaves of Betula celtiberica were collected in October 2011. The extracts obtained by increasing polarity (Bc.l.1) of n-hexane and dichloromethane showed no antioxidant activity in the range of concentrations studied DPPH, therefore have not been documented in Table 1. The remaining samples of increasing polarity exhibit strong antioxidant activity and is very strong for the methanol extract. The extracts Bc.l.2 - Ethanol and Bc.l.3 - Aqueous present AAI between 1 and 2, which corresponds to a strong antioxidant activity.
Conclusions
The results of this study show that the extracts of leaves of Betula celtiberica exhibit strong antioxidant activity.
To extract Bc.l.1 - Methanol antioxidant activity was displayed very strong (AAI> 2).
References
1. Vasconcelos, J. C.; Rothmaler, W.; Betula celtiberica Rothm. Et Vasc: Ein beitrag zur systematik der Westeuropäischen , pág. 139-188, 1940.
2. antioxidant activity index (AAU) for natural
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3. index (AAI) by the 2,2-diphenyl-1-
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