Application of Sono–photo-Fenton process for degradation of phenol derivatives in petrochemical wastewater using full factorial design of experiment

Abstract

In this study, the degradation and mineralization of petrochemical wastewater containing phenol and nitrophenol with chemical oxygen demand (COD) at 260 mg/L and total organic carbon (TOC) at 100 mg/L, were investigated by Sono–photo-Fenton process. The full factorial design of experiment was used to explore the influence of operational variables such as pH, initial concentration of hydrogen peroxide and Ferrous ions on the removal of COD. The analysis of variance (ANOVA) showed a high determination coefficient value (R2 = 0.9884, R2pred = 0.9713, R2adj = 0.9822) for removal of COD and satisfactory prediction second-order regression model. The graphical response surface plots were employed to determine the optimum conditions. The operational variables were optimized by the model as follows: the [Fe2+] = 24 mg/L, pH at 3, and [H2O2] = 500 mg/L. The results showed that at the predicted optimum conditions and after 60 min of reaction, the degradation (removal of COD) and mineralization (removal of TOC) were 76.1 and 68.7%, respectively.