Comparative study of ozone-based AOPs for degradation of Reactive Red 120

Abstract

The present work focuses on the comparative study of ozone-based advanced oxidation processes (AOPs): O3, O3/UV and O3/UV/PS to degrade synthetic wastewater containing Reactive Red 120 (RR120) dye. The effect of various parameters: pH, ozone flow rate, initial concentration of dye, persulfate dosage and UV light intensity was analyzed to assess the performance efficiency of AOPs. All three AOPs' performance was evaluated on decolorization, %TOC removal and ozone consumption. The highest degradation rate of 86.83% was achieved for O3/UV/PS, followed by 71.53% and 66.82% for O3/UV and O3 respectively. This better efficiency of O3/UV/PS is attributed to the fact that persulfate ions (S2O8 2-) upon activation produce sulfate radical (SO4 - ●), which is a powerful oxidant capable of degrading a wide variety of recalcitrant organic compounds. The study reveals that the efficiency of degradation of RR120 follows the order: O3/UV/PS > O3/UV > O3.