Preparação de compósitos de óxido de ferro e carvão ativado do ouriço (Mesocarpo) da castanha-do-brasil para remoção de corante azul de metileno em meio aquoso

Abstract

In the last years, the activated carbons produced from agro-industrial and/or extractive waste, has been the focus of númerous researches on the remediation of polluted aquatic environments, because they renewable materials are low economic value and given proper destination for disposal. Activated carbons when combined with metal oxides result in composites that are the most efficient new materials than their precursors. For this purpose, this research was produced composites of activated carbon and synthetic iron oxide at different temperatures and mass proportions. The extractive residue of Brazil nuts, mesocarp of the fruit (hedgehog), was produced in muffle by pyrolysis, impregnated with ZnCl2 at 400 and 500 °C, respectively. Iron oxide (Fe2O3) was synthesized by thermal decomposition of the ferric nitrate at 400 °C. The composites, in turn, were prepared in proportions of 2:1, 1:1 and 1:2 of their components and calcined in a muffle furnace at 400 and 500 °C, respectively. The materials were characterized by TGA, CHNS, DRX, SEM and adsorption/desorption of N2. All composites presented phases of hematite, but CP521 (ratio 2:1 and 500 oC) presented a magnetic characteristic due to the occurrence of magnetite. The 〖ASE〗_BET values of the composites varied from 274 to 630 m2 g–1 (CP411), and 1236 m2 g–1 for CA25 (method 2 and 500 oC). The kinetic data of adsorption and/or degradation of methylene blue for all materials were best fitting by the kinetic model of pseudo-second order, with R^2>0,971. Materials against methylene blue show more significant behavior for Langmuir isotherm, where the CA25 q_e=181 "mg" "g" ^(-1) (R^2=0,960) and CP 5 11 q_e=127 "mg" "g" ^(-1) (R^2=0,895), respectively. In general, the Brazil nut hedgehog presents itself as a promising material to produce iron oxide-based coals and composites for the mediation of dyes from polluted.