Synthesis of Nano N-TiO2 for modeling of petrochemical industries spent caustic wastewater photocatalitic treatment in visible light using DOE method

In this study, photocatalytic treatment was used to treat spent caustic wastewater of olefin petrochemical plants which is one of industrial wastewater with high total dissolved solids (TDS). For this purpose, by using the synthetic photocatalyst of the suspended TiO2 Doped Nitrogen(N-TiO2)and measuring the parameter of the chemical oxygen demand (COD), this parameter decrease percentage in the Photocatalyst process has been modeled and evaluated by means of Box-Behnken (BBD) design of experiment (DOE) in a double-cylindrical-shell photo-reactor. Modeling of this research showed that increasing the concentration of photocatalyst in a state of neutral pH, lead to enhance the COD removal till the optimal amount of 0.64 g/L without restrictions and 2 g/L with restrictions in the rate of 96% and 90%, respectively. In addition, the study of the parameters’ effects including oxidizer amount, aeration rate, pH and the amount of loaded catalyst indicate that all factors except pH have been had positive effect on the model and if the interactions are neglected, the COD removal efficiency will increase by increasing each of these factors (except pH).