Aplicação do processo oxidativo fenton no tratamento de efluentes têxteis

Abstract

The advanced oxidation Processes has the potential to transform many substances with difficult elimination in biodegradable substances or even easily eliminated substances by conventional physical and chemical processes, through reactions that generate active oxidizing species, such as hydroxyl free radicals (●OH). Hydrogen peroxide is the generating source more common of these radicals. The work evaluated the performance of the oxidative process advanced Fenton in the treatment of textile effluents containing direct dye Black 22. Through factorial planning 2³ with four repetitions in central points, introducing as control variables concentration of H2O2 (eighteen mmol/L, ninety mmol/L) and Fe2+ concentration (five mmol/L, ten mmol/L) and time (thirty min, sixty min) , with pH 3 ±0,2. The tests were done in batch under constant mechanical agitation. As output variables, were analyzed apparent color, true color, turbidity, COD and the consumption of H2O2. In some tests there was reduction true color and turbidity up to ninety percent. The COD reduction presented values between thirty-eight and sixty-eight. The significance analysis was performed from the effects of the studied factors on each output variable. For true color and turbidity removal, the best condition of the factorial design is the one that brings the [Fe 2+] = five mmol/L, [H2O2] = eighteen mmol/L and sixty minutes mixing times. The major drawback observed during the process was the waste formation and yellow coloring due to iron oxides.