Tratamento eletrolítico de efluentes têxteis: avaliação da eficiência do processo e do potencial ecotoxicológico utilizando diferentes bioindicadores
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Data
2019-08-05
Autores
Moraes Júnior, José Rubens
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os efluentes têxteis têm capacidade de proporcionar cor à água de rios e lagos devido aos corantes presentes em sua composição. Além dos problemas estéticos, outros compostos presentes nestes tipos de efluentes podem ser tóxicos à vida aquática. Os processos oxidativos avançados (POA) vem sendo estudados devido a vantagem de serem mais rápidos, produzirem menos resíduos e não demandarem de grandes áreas de instalação quando se comparado a tratamentos convencionais. Este trabalho teve como objetivo a degradação de efluentes simulados contendo o corante Acid blue 40, o corante Acid red 151 e efluente misto contendo ambos os corantes por tratamento eletrolítico utilizando eletrodo de titânio recoberto por titânio/rutênio (70%TiO2/30%RuO2) com área de 40 cm² em um sistema de recirculação. Foi realizado planejamento experimental e por meio de análise de superfície de resposta, configurações de tratamentos otimizados foram realizadas. Foram realizadas análises de espectrofotometria, DQO, DBO, Cor, pH, cloro residual livre e condutividade durante os processos de tratamento. Análise de espectro de infravermelho com transformada de Fourier (FTIR) foi realizada de todos os tratamentos. Foi também verificada a geração de clorofórmio por meio de análise de cromatografia gasosa e espectrometria de massa (GC-MS). Testes de ecotoxicidade com sementes de alface (Lactuca sativa) e rúcula (Eruca sativa) e com o microcrustáceo Artemia salina foram realizados durante os tratamentos. Teste de mutagenicidade foi realizado utilizando a cepa D7 da levedura Saccharomyces cerevisiae. Os tratamentos otimizados degradaram a cor inicial em concordância com o planejamento experimental. A relação DBO/DQO aumentou durante os tratamentos indicando maior biodegradabilidade dos efluentes simulados após o tratamento eletrolítico. A análise de cor em 3 comprimentos de onda indicou que os subprodutos finais de todos os tratamentos apresentam cor amarelada. Análise de espectro de infravermelho sugeriu a produção de subprodutos tóxicos como nitro compostos durante os tratamentos, com a maioria sendo degradada ao fim dos processos. A análise de GC-MS para clorofórmio indicou a presença de baixas concentrações deste composto. Os testes de ecotoxicidade com a semente de L. sativa indicou toxicidade para o tratamento contendo o efluente Acid blue 40 enquanto o teste com a semente de E. sativa e com o microcrustáceo A. salina indicaram toxicidade para o tratamento do efluente contendo o corante Acid red 151. Por fim, apesar de apresentar sensibilidade a ataque mutagênicos, a cepa S. cerevisiae D7 não indicou mutagenicidade para nenhum dos tratamentos realizados.
The textile effluents have the capacity to provide color to water from rivers and lakes due to the dyes present in their composition. In addition to aesthetic problems, other compounds present in these types of effluents can be toxic to the aquatic life. The advanced oxidative processes (AOP) have been studied due to the advantage of being faster, producing less waste and not having to spend large areas of installation when compared to conventional treatments. This work aimed at the degradation of simulated textile effluents containing the Acid blue 40 dye, Acid red 151 dye and a mixed effluent containing both dyes by electrolytic treatment using a titanium electrode covered by titanium/ruthenium (70%TiO2/30%RuO2) with an area of 40 cm² in a recirculating system. Experimental design was realized by the response surface the optimized configurations of the treatments were performed. Analysis of spectrophotometry, COD, BOD, color, pH, free residual chlorine and conductivity were performed during the treatment processes. Fourier transformed infrared spectrum analysis (FTIR) were performed in all treatments. The generation of chloroform was investigated by analysis of gas chromatography and mass spectrometry (GC-MS). Ecotoxicity tests with seeds of lettuce (Lactuca sativa) and arugula (Eruca sativa) and with the microcrustacean Artemia salina were performed for during treatments. Mutagenicity test was performed using the D7 strain of the yeast Saccharomyces cerevisiae. The optimized treatments degraded the initial color according to the experimental design. The BOD/COD ratio increased during treatments indicating higher biodegradability of the simulated effluents after electrolytic treatments. The color analysis in 3 wavelengths indicated that the final by-products of all treatments shown yellow color. The infrared spectrum analysis suggested the production of nitro-compounds during treatments, but most was degraded by the end of the processes. The GC-MS analysis for chloroform indicated the presence of low concentrations of the compound. The ecotoxicity tests with L. sativa seeds indicated toxicity for the Acid blue 40 effluent treatment while tests with E. sativa and A. salina indicated toxicity for the Acid red 151 effluent treatment. Finally, despite showing sensitivity for mutagenic attacks, the S. cerevisiae D7strain did not indicate mutagenicity for any one of the treatments performed.
The textile effluents have the capacity to provide color to water from rivers and lakes due to the dyes present in their composition. In addition to aesthetic problems, other compounds present in these types of effluents can be toxic to the aquatic life. The advanced oxidative processes (AOP) have been studied due to the advantage of being faster, producing less waste and not having to spend large areas of installation when compared to conventional treatments. This work aimed at the degradation of simulated textile effluents containing the Acid blue 40 dye, Acid red 151 dye and a mixed effluent containing both dyes by electrolytic treatment using a titanium electrode covered by titanium/ruthenium (70%TiO2/30%RuO2) with an area of 40 cm² in a recirculating system. Experimental design was realized by the response surface the optimized configurations of the treatments were performed. Analysis of spectrophotometry, COD, BOD, color, pH, free residual chlorine and conductivity were performed during the treatment processes. Fourier transformed infrared spectrum analysis (FTIR) were performed in all treatments. The generation of chloroform was investigated by analysis of gas chromatography and mass spectrometry (GC-MS). Ecotoxicity tests with seeds of lettuce (Lactuca sativa) and arugula (Eruca sativa) and with the microcrustacean Artemia salina were performed for during treatments. Mutagenicity test was performed using the D7 strain of the yeast Saccharomyces cerevisiae. The optimized treatments degraded the initial color according to the experimental design. The BOD/COD ratio increased during treatments indicating higher biodegradability of the simulated effluents after electrolytic treatments. The color analysis in 3 wavelengths indicated that the final by-products of all treatments shown yellow color. The infrared spectrum analysis suggested the production of nitro-compounds during treatments, but most was degraded by the end of the processes. The GC-MS analysis for chloroform indicated the presence of low concentrations of the compound. The ecotoxicity tests with L. sativa seeds indicated toxicity for the Acid blue 40 effluent treatment while tests with E. sativa and A. salina indicated toxicity for the Acid red 151 effluent treatment. Finally, despite showing sensitivity for mutagenic attacks, the S. cerevisiae D7strain did not indicate mutagenicity for any one of the treatments performed.
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Palavras-chave
Processos oxidativos avançados, Degradação de corantes têxteis, Acid blue 40, Acid red 151, Índice de biodegradabilidade, Mutagenicidade, Lactuca sativa, Eruca sativa, Artemia salina, Saccharomyces cerevisiae D7, Advanced Oxidative Processes, Degradation of textile dyes, Biodegradability index