Optimization of nitrobenzene wastewater treatment with O3/H2O2 in a rotating packed bed using response surface methodology

Effects on the removal efficiency of nitrobenzene treated by O3/H2O2 in a rotating packed bed (RPB) were optimized with response surface methodology (RSM). Interaction effects between influence of H2O2 concentration, gas-phase ozone concentration, liquid flow rate, and high-gravity factor on the removal efficiency of nitrobenzene wastewater treatment with O3/H2O2 in a RPB were investigated. The results indicate that the influence priority on nitrobenzene removal is high-gravity factor, gas-phase ozone concentration, H2O2 concentration, and liquid flow rate. Significant interaction effects of H2O2 concentration and gas-phase ozone concentration, gas-phase ozone concentration, and high-gravity factor were observed. The optimum treatment conditions after optimizing were H2O2 concentration 5.7 mmol L−1, gas-phase ozone concentration 50 mg L−1, liquid flow rate 125 L h−1, and high-gravity factor 100. Under the optimal reaction conditions, the actual removal efficiency of nitrobenzene could reach 76.1% fast in a short-treatment time of 10 min. And the theoretical value was 78.2%. The deviation between the experiment test result and the predicted value of RSM-fitting equation was 2.68%, which indicate that the RSM-fitting equation could be used to predict the removal efficiency of nitrobenzene treated by O3/H2O2 in a RPB and optimize the treatment conditions.