Abstract

Zn2SnO4 particles with the cubic shape are prepared via a two-step process, including co-precipitation and high-temperature solid state reaction procedures. The prepared photocatalyst has been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV–vis diffuse reflectance spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. Response surface methodology (RSM) was used to model and optimize four key independent variables, namely catalyst dosage, pollutant initial concentration, pH and distance between UV source and surface of solution (D) for photocatalytic degradation of Basic Red 46 as model pollutant. The proposed quadratic model was in accordance with the experimental results with correlation coefficient of 98.4%. The Pareto analysis indicated that the most important variable for the photocatalytic degradation of BR 46 was the distance between surface of solution and UV source (34.536%), followed by pure quadratic interactions of catalyst dosage (21.049%) and pH (14.309). Optimal experimental conditions found for dye removal were ZTO dosage of 110 mg/l, initial dye concentration of 17 mg/l, D = 10 cm and pH of 8.5. The predicted degradation efficiency under the optimal conditions determined by the proposed model was 95.3%. Confirmatory experiment was carried out under the optimal conditions and the degradation efficiency of 94.7% was observed, which closely agreed with the predicted value.