Utilização de biossorventes alternativos na remoção de corantes têxteis

Abstract

The textile sector is one of the main contributors to the pollution of water resources due to the release of large volumes of effluents which contain high organic load and highly visible coloring. The diversity of products used in textile processing, especially synthetic dyes, makes the effluent variable and difficult to treat. Therefore, this study aimed to analyze the biosorption process of blue 5G and red 4B reactive dyes of synthetic solutions using the biosorbents Salvinia sp. and rice husk in natura, both pretreated in acid medium with H3PO4 and C6H8O7, respectively. Physico-chemical analyses of pH, Turbidity and DQO were carried out in order to verify a possible interference of the biosorbents in the dye solutions composition. The results obtained on the biosorption tests indicated that Salvinia sp. modified with H3PO4 was the biosorbent that showed the best performance in removing both dyes, with 62% efficiency for the blue reactive dye and 41% for the red one. For the rice husk, the greatest efficiency was 21%, which has been confirmed by the biomass that was modified in the removal of the red dye. Regarding isotherms, both models, Langmuir and Freundlich, adequately described chemical equilibrium results, indicating the maximum adsorption capacity of 10.2 mg g-1 for the rice husk in the blue dye and 5.1 mg g-1 for Salvinia sp. in the red dye, at temperature conditions of 30 °C and pH 2.26 and 3.21. By the results of physico-chemical analyses, it was found that the biosorbents possibly interfered in the dye solutions, given that the results of all the assessed parameters have gradually increased over contact time. In general, the biosorption process of textile dyes, under the conditions of this study, by the biosorbents Salvinia sp. and rice husk, proved to be a promising alternative for dyes removal.