Preparo e caracterização de compósitos de carvão ativado de ossos e óxido de ferro para a utilização na remoção de corantes por ação combinada de adsorção e oxidação na presença de H2O2

Abstract

This study aimed to prepare and characterize activated charcoal composites of bovine bones (CA) and iron oxide. The samples were prepared using a CA of commercial bones (CA-0) that got impregnated with a FeSO4.7H2O solution and two other basic solutions (KOH and KNO3) to precipitate the iron oxides. Two samples of composites were prepared with different iron oxide contents and denominated as CA-1 and CA-2, in addition to a third sample denominated as CA-1T, obtained by submitting the CA-1 sample to an acid treatment in order to grant a lower value of pHPCZ to this sample. CA and Fe/CA composites were characterized through iron oxide concentration determination, iodine number determination, N2 physisorption analysis, Fe leaching test, point of zero charge (pHPCZ), thermogravimetric analysis (TG), H2O2 decomposition and infrared spectroscopy. Results show different types of iron oxides present in the indicated composites by coloring, magnetic behavior and TG. The iron content in the composites was aapproximately 4,2 %. Iron oxides presence showed little interference in the composites porosity. CA sample and CA-2 composite presented alkaline pHPCZ (above 9), while CA-1 and CA-1T samples presented pHPCZ of 6,5 and 5,3, respectively. The adsorption/oxidation tests of a textile dye evidenced that composites were effective in the remotion of the dye and process occurs by combinated action of adsorption and oxidation in presence of H2O2.