Degradação de corantes azo por processo enzimático (peroxidase de Brassica rapa) e biofiltro anaeróbio-aeróbio

Abstract

In this study, the potential of a turnip peroxidase (Brassica rapa) in catalyze the degradation of the textile azo dyes Crystal Ponceau 6R (CP6R) and Reactive Red 239 (RR239) was evaluated. The optimum parameters of the enzymatic oxidation of CP6R and RR239 dyes were determined. The enzyme showed to be a highly e ective catalyst in discoloration of CP6R dye at pH 3, 4 and 5. However, the optimum pH for both dyes was found to be 4. The optimal contact time for removal of CP6R and RR239 was 0.75 min and 48.3 min, respectively. Under optimal conditions, 98% color removal was achieved for CP6R and 79% for RR239. The results showed that RR239 dye is much more resistant to degradation by the used peroxidase. The degradation of a synthetic wastewater containing the RR239 dye by means of sequential biological - enzymatic (B+E) and enzymatic - biological (E+B) treatment was also investigated in this work. The enzymatic process was the main responsible for the removal of color, although it was not e ective in the removal of organic matter. The biological process (anaerobic-aerobic bio lter) facilitated the removal of COD (anaerobic reactor) and ammonium (aerobic reactor). The B+E sequential treatment was e ective in the degradation of the wastewater and exhibited better performance than the E+B treatment, reaching color, COD and ammonium removal percentages of 94%, 90% and 98%, respectively.