Facile Synthesis of Tin Dioxide Nanoparticles for Photocatalytic Degradation of Congo Red Dye in Aqueous Solution

Abstract

This research work reports an approach used to prepare a SnO2 photocatalyst by precipitation and calcination pathways and describes an investigation of the effects of preparation parameters on SnO2 yield. The SnO2 photocatalyst was further used for the photocatalytic degradation of Congo red (CR) dye, and the removal efficiency was optimized using response surface methodology. The results indicate that the SnO2 photocatalyst yield was the highest in 0.05 M of the precursor, stannous chloride and 28 wt % ammonia as the precipitant, pH 10, at 30 °C. The transmission electron microscopy results of the SnO2 photocatalyst illustrate that the average particle size was mainly around 30–50 nm and had a solid spherical shape. The X-ray diffraction results reveal that the prepared sample had a highly crystalline SnO2 rutile crystal structure. The prediction and experimental results of the Response surface methodology (RSM) indicate that, when the reaction time was 97 min, the operating temperature was 47 °C, the photocatalyst dosage was 751 mg/L, and the optimal degradation rate of the CR dye was 100%. After five consecutive photodegradation reactions, the degradation rate remained at 100%. The results demonstrated that the SnO2 photocatalyst prepared in this study possesses excellent reusability.