Photocatalytic degradation of an aqueous sulfamethoxazole over the metallic silver and Keggin unit codoped titania nanocomposites

A series of metallic silver and Keggin unit codoped titania nanocomposites (H3PW12O40/Ag–TiO2) were prepared through a single step sol–gel-hydrothermal method. The composites mainly exhibited an anatase phase, featuring micro–meso dual porosity with metallic Ag nanoparticles homogeneously dispersed on the surface of the H3PW12O40/Ag–TiO2; meanwhile, they showed photoresponses to both the UV- and visible-light regions. As the novel composite photocatalysts, the materials were used to degrade a light-insensitive target compound, sulfamethoxazole (SMZ), under Xe lamp irradiation (320 nm < λ < 680 nm). The influences of the experimental parameters such as the initial acidity of the reaction system, the initial concentration of SMZ, and the amount of the catalyst on the photocatalytic activity of the H3PW12O40/Ag–TiO2 were studied; additionally, the photocatalytic degradation pathway of an aqueous SMZ over H3PW12O40/Ag–TiO2 was proposed by analyzing the reaction intermediates and final products identified during the photcatalytic process. Finally, the recyclability of the photocatalyst was evaluated.