Optimization of photooxidative removal of p-nitrophenol in a spinning disc photoreactor using response surface methodology

Abstract

In this article, response surface methodology (RSM) was used to obtain optimum conditions for removal of p-nitrophenol (PNP) by UV/H2O2 process using spinning disk photoreactor (SDP). For this purpose, the effect of five independent variables, the initial concentration of PNP, the initial concentration of H2O2, pH, solution volume, and irradiation time on the PNP removal percent, was investigated. Central composite design, one of the response surface techniques used for process optimization. The results showed a good agreement between the RSM predicted and experimental data with “R2” and “Adjusted R2” of 0.9692 and 0.9480, respectively. In addition, “Predicted R2” of 0.8909 is in reasonable agreement with “Adjusted R2” of 0.9488. At optimal conditions, that is, PNP concentration of 20.78 mg L−1, H2O2 concentration of 1355.83 mg L−1, solution volume of 566.08 mL, irradiation time of 12.30 min, and pH of 4.59 the removal percent predicted by RSM is 100% which has good correspondence with its experimental value (98.67%).