Employing a new catalytic ozonation(O3/MnO2/CP) for degradation of Nitro toluene in aqueous environment using Box-Behnken experimental design

Abstract

In this work, the degradation of Nitro toluene (NT) which is one of the constituents of petrochemical wastewater was explored byMnO2/Clinoptilolite/O3 process. The Box-Behnken experimental design was used and the effect of some operating parameters such as concentration of pollutant, initial pH, and amount of MnO2/Cp was inspected. A radical mechanism with the formation of an anion radical ( before hydroxyl radical is proposed for describing the interaction between ozone and MnO2/Cp . The optimum conditions predicted by the model were as the following: [MnO2/Cp ] = 0.45 mg/L, pH at 8.5, ozonation time at 48 min and [NT] = 30 mg/L.In optimum condition, the removal of NT and Chemical Oxygen Demand (COD) was 99.8, and 74% respectively. The removal of NT in the ozone along with MnO2/CP was higher than the sum of the separate processes of single adsorption of catalyst (6%) at 0.6 mg/L and single ozonation(79%).