An efficient Ag2SO4-deposited ZnO in photocatalytic removal of indigo carmine and phenol under outdoor light irradiation

Silver sulfate (Ag2SO4) was successfully deposited on ZnO via a simple impregnation method. The as-synthesized sample was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, fourier transform infrared spectroscopy, and UV-vis diffuse reflectance spectroscopy. The photocatalytic activities of pure ZnO and 10wt% Ag2SO4/ZnO were evaluated for the removal of indigo carmine and phenol under outdoor light irradiation. The results showed that the photocatalytic activity of Ag2SO4/ZnO was higher than those of pure ZnO and commercial TiO2 for both pollutants removal. Identification of intermediate products and radical scavengers test were also carried out. The effects of process variables such as initial pollutants concentration and solution pH toward the photocatalytic degradation efficiency were also investigated. The optimum initial pollutants concentration was found to be 10mg/L for both pollutants. The photo removal of indigo carmine was favorable at pH 7 while in the case of phenol, maximum degradation rate was observed at pH 5. The excellent photocatalytic property of Ag2SO4-deposited ZnO suggested its potential usage for practical applications in wastewater remediation.