Efficient water disinfection with Ag₂WO₄-doped mesoporous g-C₃N₄ under visible light

Ag₂WO₄/g-C₃N₄ composite photocatalyst was synthesized by polymerization of thiourea and ammonia chloride combined with the deposition-precipitation method, which was applied as an efficient visible-light driven photocatalyst for inactivating Escherichia coli (E. coli). The physicochemical properties of these photocatalysts were systematically characterized by various techniques such as SEM, TEM, XRD, FT-IR, BET, UV-vis DRS and PL. The synthesized photocatalysts exhibited outstandingly enhanced photocatalytic disinfection efficiency compared with that of pure g-C₃N₄ and Ag₂WO₄ under visible light. Furthermore, the optimal mass ratio of the Ag₂WO₄ to g-C₃N₄ was 5wt%, and a number of live bacteria could be completely inactivated with Ag₂WO₄(5%)/g-C₃N₄ (100μg/mL) after 90min under visible light irradiation. The high disinfection efficiency is due to the synergetic effect between g-C₃N₄ and Ag₂WO₄, including a good distribution of Ag₂WO₄ particles on the surface of g-C₃N₄ and an improved separation rate of photogenerated electron-hole pairs. The enhanced disinfection mechanism was also investigated using photogenerated current densities and electrochemical impedance spectroscopy (EIS). Considering the bulk availability and excellent disinfection activity of Ag₂WO₄/g-C₃N₄ composite, it is a promising solar-driven photocatalyst for cleaning the microbial contaminated water.