employing a new catalytic ozonation (o3/mno2/cp) for degradation of nitro toluene in aqueous environment using box-behnken experimental design

In this work, the degradation of nitro toluene (nt) which is one of the constituents of petrochemical wastewater was explored by mno2/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 (𝑂2•−) 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%).