Facile Synthesis of Ag/ZnO Photocatalysts on the Degradation of Diuron Herbicide Under Simulated Solar Light and the Investigation of Its Antibacterial Activity for Waste-Water Treatment

Abstract

Nanocrystalline Ag/ZnO powders have been successfully prepared by a modified polyol process using triethylene-glycol (TEG) as solvent, reducing and stabilizing agent. The synthesis procedure has been conducted without any post-synthesis thermal treatment. The structural and optical properties have been characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption study, inductively coupled plasma optical emission spectroscopy and UV–Vis diffuse reflectance spectroscopy. The photocatalytic activity of Ag/ZnO materials has been studied by analyzing the degradation of an herbicide, diuron, under solar light. Ag/ZnO photocatalysts with optimized x = 0.7% Ag content showed 14 times higher rate of degradation than that of unmodified ZnO. We attribute these observations to the addition of silver nanoparticles allowing interfacial oxide-to-metal electron transfer within the hybrid Ag/ZnO photocatalyst. The inhibitory and bactericidal activities of samples have been tested against Gram-negative bacteria; Escherichia coli, Salmonella typhimurium and gram-positive bacteria; Staphylococcus aureus, Enterococcus faecium and Candida albicans. The results showed that the Ag/ZnO can be used as photocatalysts and antibacterial agents for potential practical applications in the wastewater treatment. Schematic of the proposed photocatalytic and bactericidal mechanism of Ag/ZnO nanostructure.