Enhanced bacterial disinfection by Bi 2 MoO 6 -AgBr under visible light irradiation.

Bi2 MoO6 -AgBr hybrid photocatalyst was synthesized via a mixed solvothermal-precipitation method. The as-synthesized photocatalysts were well characterized by Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopic (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX), high resolution transmission electron microscope (HRTEM), UV-vis diffuse reflectance spectra (DRS), as well as photoluminescence spectra (PL). The visible light driven (VLD) disinfection activity of Bi2 MoO6 -AgBr was tested using Escherichia coli as the model bacteria. Complete disinfection of 3×106 CFU mL-1 viable cell density was observed in 90min under visible light irradiation for Bi2 MoO6 -AgBr with the optimal AgBr amount. Ag+ released from the photocatalysts did not affect the inactivation process due to the low concentration. Whereas, photo-generated holes, H2 O2 and O2 - were the main active species involved in the photocatalytic disinfection reaction. The presence of O2 and direct contact between photocatalysts and bacterial cells were found to be indispensable for the cell inactivation. In addition, neutral and slight alkaline conditions was beneficial for the disinfection process.