Optimization and kinetic evaluation of acid blue 193 degradation by UV/peroxydisulfate oxidation using response surface methodology

Abstract

The optimization of process conditions for the degradation of Acid Blue 193 by UV/peroxydisulfate was investigated using response surface methodology (RSM). The effects of four parameters namely initial K₂S₂O₈ concentration, UV irradiation, temperature, and initial dye concentration on two process responses, color removal and the rate constants of the first-order kinetic equations, were investigated using a second-order polynomial multiple regression model. The analysis of variance (ANOVA) explained a high determination coefficient (R²) value of 0.927-0.967, which ensures a good fit of the first-order regression model with the experimental data. The central composite design (CCD) was used to optimize the process conditions, which showed that an initial K₂S₂O₈concentration of 5 mM, UV irradiation of 250 W, temperature of 50 °C, and the initial dye concentration of 40 mg/L were the best conditions. Under optimum conditions, the maximum color removal from the wastewater and the rate constants of the first-order kinetic equation were 100% and 0.086 min^--1, respectively.