Application of chitin and chitosan extracted from silkworm chrysalides in the treatment of textile effluents contaminated with remazol dyes/Aplicacao de quitina e quitosana extraidas de crisalidas do bicho-da-seda no tratamento de efluentes texteis contaminados com corantes remazol

Chitin extracted from silkworm chrysalides was used to prepare chitosan applied in this investigation. Adsorption studies were carried out in column and in aqueous suspension with two dyes, blue remazol (RN) and black remazol 5 (RB). The study showed that adsorption is better in the chitosan-packed column than in the chitin-packed one. However, the comparison of the adsorption in column and in suspension revealed better results for the latter. The plotted Langmuir isotherm did not indicate significant difference in the theoretical capacity of saturation of the monolayer (Qo) for either dye. The application of the adsorption process to actual conditions was evaluated by adsorption assays of actual textile effluents. In acid pH, chitosan adsorbed the dyes responsible for the effluent coloration completely. This study showed that the use of chitosan obtained from silkworm chrysalides is a viable alternative for the immobilization of dyes in textile industry effluents. Keywords: chitin, chitosan, silkworm, adsorption, dyes. Quitina extraida de crisalidas do bicho-da-seda foram utilizadas para preparar a quitosana utilizada neste estudo. Os experimentos de adsorcao foram feitos em fluxo continuo de solucoes de corantes: azul remazol (RN) e preto remazol 5 (RB) atraves de uma coluna recheada de quitina ou quitosana, ou em suspensao. Os resultados mostraram que a adsorcao foi mais eficiente nas colunas de quitosana do que nas colunas de quitina e os experimentos em suspensao foram superiores em relacao aos feitos em coluna. As isotermas de Langmuir nao indicam diferenca significativa na capacidade teorica de saturacao da monocamada (Qo) para ambos os corantes. A aplicacao do processo de adsorcao em condicoes reais foi avaliada atraves de experimentos realizados com efluentes texteis reais. Em pH acido a quitosana adsorveu completamente os corantes responsaveis pela coloracao dos efluentes texteis. Esse estudo revelou que a quitosana obtida de crisalidas do bicho-da-seda e uma alternativa viavel de imobilizacao de corantes para a industria textil. Palavras-chave: quitina, quitosana, bicho-da-seda, adsorcao, corantes.