Optimization and Modeling of Photocatalytic Degradation of Azo Dye Using a Response Surface Methodology (RSM) Based on the Central Composite Design with Immobilized Titania Nanoparticles

The experimental design methodology was used to model and optimize the operational parameters of the photocatalytic degradation of Acid Red 73 using immobilized TiO2 nanoparticles. Four experimental parameters were chosen as independent variables: pH, initial dye concentration, H2O2 concentration, and anion concentration. A multivariate experimental design was used to establish a quadratic model as a functional relationship between the efficiency of Acid Red 73 degradation (response) and four independent variables. The degradation efficiency was significantly affected by the initial dye concentration and the pH. The optimal values of the parameters were found to be a pH of 3, an initial dye concentration of 25 mg/L, an H2O2 concentration of 0.5 mg/L, and an anion concentration of 0.69 mg/L. The degradation efficiency approached 92.24% under optimal conditions. Regression analysis with an R-2 value of 0.9785 indicated a satisfactory correlation between the experimental data and predicted values.