Preparação de carvão ativado a partir de resíduos de erva-mate e seu uso como adsorvente na remoção de poluente orgânico em solução aquosa

Abstract

Activated carbon prepared from yerba mate (Ilex Paraguariensis) has been used as adsorbent for the removal of tannery dye from aqueous solution. The activated carbon was prepared by pyrolysis process, under nitrogen atmosphere, at 700 oC for two hours. The product was characterized by N2 adsorption-desorption isotherms and scanning electronic microscopy, and it showed a mesoporous texture, with high surface area, 537.4 m2 g-1. Parameters such as initial dye concentration, contact time and pH were investigated in adsorption process. It has been observed that all parameters influenced the adsorption capacity. Both Freundlich and Langmuir models satisfactorily fitted the adsorption isotherm data. The maximum adsorption capacity verified was 244.5 mg g-1. The adsorption kinetics of the tannery dye on activated carbon prepared from yerba mate followed pseudo-second-order model. The adsorption process was found to be controlled by both external mass-transfer and intraparticle diffusion, but the external diffusion was the dominating process. This work highlights the potential application of activated carbon produced from yerba mate in the field of adsorption.