Avaliação e cinética da retenção de corantes utilizando quitosana como adsorvente de baixo custo.

Abstract

This study aimed to develop a low cost material for sorption of dyes in industrial effluents from chitosan, studies in order to determine the optimum parameters and mechanisms involved in that process. The use of kinetic models had the order to elucidate the nature of the sorption processes. The characterization of the biopolymer techniques were used to pigmentary, conductometric titration, infrared spectroscopy, differential thermal analysis, thermal analysis, differential scanning calorimetry and scanning electron microscopy. The retention of dyes from aqueous solutions on chitosan was evaluated using sorption tests, the method of finite bath, at a predefined pH value at different times of contact sorbent: sorbate. The concentrations of dye samples studied, as well as their supernatants after sorption tests were determined by UV-Visible spectroscopy. In the study of the kinetics of retention of the supernatant, the values of reaction order was determined by models of integrated reaction rates of first and second order. The removal of dyes can be regarded as a process of electrostatic adsorbent- adsorbate interaction, considering the pH range of the reaction medium. The results suggest that chitosan has application as an effective adsorbent to remove dyes in wastewater, particularly those of acidic nature, according to the values determined in the reaction kinetics, we can identify the dye methyl orange dye which was obtained better performance compared to adsorption experiments with the chitosan membrane, taking into account the contact times studied. This is mainly due to nature of the adsorbate. Because it is classified as a basic dye, crystal violet did not show how to interact effectively adsorb to the chitosan membrane.