Synthesis of Nanoparticles of Magnetic Iron Oxides Associated with Biochar and Bonechar and Its Effects on Lead Sorption.

Pollution caused by industrial waste, specially caused by lead, has been causing serious damage to the environment, affecting rivers, soils, plants, animals and humans. The objective of this work was to evaluate the performance of biochar and bonechar pure or modified with iron oxides the removal of lead. It was synthesized iron oxide ferrimagnetic nanoparticles associated to biochar and bonechar using ratios of biochar:iron and bonechar: iron of 0.5:1; 1:1; 2:1; 3:1 and 4:1. The pure and synthesized materials were characterized by total chemical analysis, X-rays diffraction, mass specific magnetic susceptibility, specific surface area and scanning electron microscopy. It was also carried out the determination of the remaining lead content, adsorbed and desorbed from the materials. As results, the iron content of the synthesized samples was compatible with the expected values in the samples and the pH of the synthesized materials was slightly acidic. The X-rays diffractograms showed the formation of magnetite in most of the treatments and the magnetic susceptibility showed variation according to the change ratio biochar:iron and bonechar:iron. There was a reduction of the specific surface area of the modified biochar and an increase in the modified bonechar area. The scanning electron microscopy images showed the presence of the magnetite in the modified materials. Modified bonechars were more efficient than the pure bonechars for the adsorption of lead, and the modified biochars did not show improvements in the adsorption capacity.