Oxidação do Benzo(a)pireno em Matrizes Aquosas por Magnetita Dopada com Cobalto Combinada com Peróxido de Hidrogênio

Abstract

Polycyclic aromatic hydrocarbons (PAHs), are substances of increasing concern to the environment due to their toxic, carcinogenic and mutagenic character. Major anthropogenic sources of PAHs include the incomplete combustion of organic materials (e.g. oil, petrol, coal, and wood). The concern about water contamination and the consequent human exposure has encouraged the development of new methods for PAHs removal. The purpose of this work was to study the feasibility of a degradation process of benzo(a)pyrene in aqueous matrices by oxidation with Fenton's reagent and utilization of pure and doped magnetites (with Co +2 ions replacing some of the Fe 2+ ions) and hydrogen peroxide. Under the best experimental conditions, a modified Fenton-type reaction was performed at near neutral pH (pH = 6.0); H2O2 dose = 0,3 mol.L -1 ; benzo(a)pyrene = 4.0 mg.L -1 and doped magnetites with Co +2 = 30,0 mg. The presence of Co +2 in the magnetite structure produced a remarkable increase in the degradation of benzo(a)pyrene. It was possible to remove about 53,0% of benzo(a)pyrene in 300 minutes of reaction at 25 o C. This study showed that the degradation of benzo(a)pyrene by magnetites doped with cobalt is a viable process in water matrices. It was observed that the substitution of some Fe 2+ ions with Co +2 ions in magnetite produced an increase in the activity of degradation of benzo(a)pyrene.