Estudo da interação adsortiva entre Saccharomyces cerevisiae, Moringa oleifera e três classes de corantes texteis
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2017-02-24
Autores
Pecora, Hengli Barbosa [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A indústria têxtil utiliza grandes quantidades de água e em seus processos industriais ocorrem muitas perdas de produtos como corantes, detergentes e engomantes, assim elevadas quantidades de efluentes carregados com diversas substâncias são gerados. Esses efluentes trazem os corantes como principais substancias contaminantes. Os corantes são moléculas estáveis, de difícil degradação e acarretam graves conseqüências prejudiciais aos organismos. Devido à grande problemática causada por essas substâncias, diversos tratamentos vêem sendo estudados, entre eles, tratamentos alternativos que associem baixo custo, disponibilidade e ausência de subprodutos tóxicos. A biossorção e floculação são processos que se mostram cada vez mais promissores na remoção de corantes provenientes de efluentes têxteis. A levedura Saccharomyces cerevisiae é um adsorvente eficiente, porem uma vez que ocorre o processo de adsorção do corante na levedura, esta precisa passar por algum processo para que decante. A Moringa oleifera é uma espécie arbórea já utilizada no tratamento de clarificação de águas turvas, contendo em sua semente uma proteína com grande potencial de coagulação/floculação. Portanto, o presente trabalho propõe avaliar o uso de Moringa oleifera e Saccharomyces cerevisiae no tratamento de remoção dos corantes Acid Orange 7, Direct Violet 51 e Procion Red HE7B em soluções aquosas, analisando a descoloração, a fitotoxicidade e possíveis alterações moleculares das amostras. Os tratamentos foram feitos utilizando-se diferentes quantidades de leveduras liofilizadas, pó de sementes de Moringa oleifera e sobrenadante de suspensão de pó de sementes de Moringa oleifera nos valores de pH 2,5; 4,5 e 6,5, e as amostras foram analisadas utilizando-se espectrofotometria UV-VIS e FTIR. Para os bioensaios de fitotoxicidade as espécies Lactuca sativa e Eruca sativa foram utilizadas como organismos teste, sendo as sementes expostas a soluções dos corantes em diferentes concentrações, além de serem expostas as amostras dos corantes após os tratamentos. Foi possível verificar mediante analises dos resultados, que os tratamentos utilizando leveduras são muito eficientes no pH 2,5, chegando a alcançar 90% de remoção dos corantes Acid Orange 7 e Direct Violet 51, e até 80% do Procion Red HE7B, porém, sua capacidade adsortiva diminui drasticamente em valores de pH menos ácidos. Os tratamentos utilizando se sementes de M. oleifera, tanto em pó quanto o sobrenadante da suspensão do pó, também se mostraram mais eficientes no pH 2,5, porem a capacidade de remoção dos corantes não altera muito com a mudança do pH. Nos testes de fitotoxicidade dos corantes a espécie L. sativa apresentou mais sensibilidade à presença dos corantes do que E. sativa, e o corante Acid Orange 7 se mostrou o mais tóxico, seguido do Direct Violet 51 e Procion Red HE7B. De modo geral, a fitotoxicidade das amostras após tratamentos aumentam, devido à ação de enzimas extracelulares que reagem com as moléculas de corante e geram metabolitos tóxicos. Os resultados obtidos através das analises de FTIR realizadas com os corantes antes e depois dos tratamentos confirmaram a produção de subprodutos pela degradação das moléculas.
The textile industry uses large volumes of water and in industrial processes many losses of products like dyes, detergents and gouges occur, so high amounts of effluents loaded with various substances are generated. These effluents bring the dyes as the main contaminating substances. Dyes are stable molecules that are difficult to degrade and have serious harmful consequences for organisms. Due to the great problem caused by these substances, several treatments have been studied, among them alternative treatments that associate low cost, availability and absence of toxic byproducts. Biosorption and flocculation are processes that are increasingly promising in the removal of dyes from textile effluents. Yeast Saccharomyces cerevisiae is an efficient adsorbent, however, since the process of adsorption of the dye in the yeast takes place, it needs to undergo some process for it to decant. Moringa oleifera is an arboreal species already used in the treatment of clarification of turbid waters, containing in its seed a protein with great coagulation/flocculation potential. Therefore, the present work proposes to evaluate the use of Moringa oleifera and Saccharomyces cerevisiae in the treatment of Acid Orange 7, Direct Violet 51 and Procion Red HE7B dyes in aqueous solutions, analyzing discoloration, phytotoxicity and possible molecular alterations of the samples. The treatments were done using different amounts of lyophilized yeast, Moringa oleifera seed powder and Moringa oleifera seed powder suspension supernatant at pH 2.5; 4.5 and 6.5, and the samples were analyzed using UV-VIS spectrophotometry and FTIR. For the phytotoxicity tests the species Lactuca sativa and Eruca sativa were used as test organisms, the seeds being exposed to solutions of the dyes at different concentrations, besides the dye samples were exposed after the treatments. It was possible to verify through the analysis of the results that the treatments using yeasts are very efficient at pH 2.5, reaching 90% of the Acid Orange 7 and Direct Violet 51 dyes, and up to 80% of the Procion Red HE7B. Its adsorptive capacity decreases dramatically at lower acid pH values. The treatments using M. oleifera seeds both powder and supernatant from the powder suspension were also more efficient at pH 2.5, but the dye removal ability does not change much with the pH change. In the tests of phytotoxicity of the dyes the L. sativa species presented more sensitivity to the presence of the dyes than E. sativa, and the dye Acid Orange 7 proved to be the most toxic, followed by Direct Violet 51 and Procion Red HE7B. In general, the phytotoxicity of the samples after treatments increase due to the action of extracellular enzymes that react with the dye molecules and generate toxic metabolites. The results obtained through the FTIR analyzes performed with the dyes before and after the treatments confirmed the production of byproducts by the degradation of the molecules.
The textile industry uses large volumes of water and in industrial processes many losses of products like dyes, detergents and gouges occur, so high amounts of effluents loaded with various substances are generated. These effluents bring the dyes as the main contaminating substances. Dyes are stable molecules that are difficult to degrade and have serious harmful consequences for organisms. Due to the great problem caused by these substances, several treatments have been studied, among them alternative treatments that associate low cost, availability and absence of toxic byproducts. Biosorption and flocculation are processes that are increasingly promising in the removal of dyes from textile effluents. Yeast Saccharomyces cerevisiae is an efficient adsorbent, however, since the process of adsorption of the dye in the yeast takes place, it needs to undergo some process for it to decant. Moringa oleifera is an arboreal species already used in the treatment of clarification of turbid waters, containing in its seed a protein with great coagulation/flocculation potential. Therefore, the present work proposes to evaluate the use of Moringa oleifera and Saccharomyces cerevisiae in the treatment of Acid Orange 7, Direct Violet 51 and Procion Red HE7B dyes in aqueous solutions, analyzing discoloration, phytotoxicity and possible molecular alterations of the samples. The treatments were done using different amounts of lyophilized yeast, Moringa oleifera seed powder and Moringa oleifera seed powder suspension supernatant at pH 2.5; 4.5 and 6.5, and the samples were analyzed using UV-VIS spectrophotometry and FTIR. For the phytotoxicity tests the species Lactuca sativa and Eruca sativa were used as test organisms, the seeds being exposed to solutions of the dyes at different concentrations, besides the dye samples were exposed after the treatments. It was possible to verify through the analysis of the results that the treatments using yeasts are very efficient at pH 2.5, reaching 90% of the Acid Orange 7 and Direct Violet 51 dyes, and up to 80% of the Procion Red HE7B. Its adsorptive capacity decreases dramatically at lower acid pH values. The treatments using M. oleifera seeds both powder and supernatant from the powder suspension were also more efficient at pH 2.5, but the dye removal ability does not change much with the pH change. In the tests of phytotoxicity of the dyes the L. sativa species presented more sensitivity to the presence of the dyes than E. sativa, and the dye Acid Orange 7 proved to be the most toxic, followed by Direct Violet 51 and Procion Red HE7B. In general, the phytotoxicity of the samples after treatments increase due to the action of extracellular enzymes that react with the dye molecules and generate toxic metabolites. The results obtained through the FTIR analyzes performed with the dyes before and after the treatments confirmed the production of byproducts by the degradation of the molecules.
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Corantes têxteis, Biossorção, Coagulação, Moringa oleifera, Saccharomyces cerevisiae