Fenton oxidation of reactive black 5: Effect of mixing intensity and reagent addition strategy

This study investigates the effect of mixing intensity and reagents addition strategy on Fenton's reagent degrading a common reactive diazo type dyestuff, Reactive Black 5. Within the experimental conditions used in the study, the effect of mixing intensity on TOC removal was observed to be both significant and complex. Using factorial analysis, it was found that if the reagents are added near to each other, higher mixing intensity will enhance the effectiveness of the degradation process. However, a very high mixing level may cause reduction in performance. It was also observed that the mixing intensity effect interacts with Fe2+ or/and H2O2 dosage. The benefit of increasing mixing intensity appears to be higher for lower reagents dosage. The effect of reagents addition strategy was found to be inter-dependent with mixing intensity level. It was also deduced that proper chemical addition strategy could be used to reduce the mixing intensity requirement of the process.