OXIDAÇÃO QUÍMICA DO CORANTE AZUL DE METILENO UTILIZANDO PROCESSOS OXIDATIVOS AVANÇADOS (POAs)

Abstract

This study describes the chemical oxidation in acid medium (pH 2.5) of methylene blue dye (MB) by Fenton process using Fe2+ or Fe3+ ions, as well as the combined Fenton process with Cu2+ ions. The MB degradation tests were conducted by the 22

factorial design with triplicate at the midpoint. There was the study of variation of two parameters: hydrogen peroxide (H2O2) concentration and iron/copper ions. The experiments were conducted in a single compartment container containing 100 mL of MB solution and conducted under constant agitation and at room temperature (± 27 °c). The results obtained for the level (+ +), i.e.; the maximum concentrations of H2O2 (100 mg l-1 ) and Fe

2+ ions (12 mg l- 1

) indicated that there was a reduction of 96.1% in the color removal and 99.4% in the MB decay of concentration. In this case, the process of the degradation kinetics was of pseudo-first order, and the value of the apparent rate constant (kapp) was 9,1x10-3 min-1

. There was an increase in the catalytic activity in the MB

degradation when used the Cu2+/Fe2+

ions in the process, reaching 88% of decay

in the concentration and for the process that used, Cu2+/Fe3+

ions the decay was 80% after 90 minutes of reaction. For both experiments the H2O2 concentration employed was 75 mg L 1 and of the Fe 2+, Fe 3+ and Cu 2+ ions was 8 mg L -1. The amount of soluble residual iron was determined with the regeneration of Fe2+ ions in the medium, in which the concentration of H2O2 added was completely consumed.