Enhanced Escherichia coli inactivation and oxytetracycline hydrochloride degradation by a Z-scheme silver iodide decorated bismuth vanadate nanocomposite under visible light irradiation

Novel Z-scheme AgI/BiVO4 photocatalysts were fabricated by a chemical deposition-precipitation approach. The photocatalytic activities of the obtained catalysts were evaluated by disinfection of Escherichia coli (E. coli) and degradation of oxytetracycline hydrochloride (OTC-HC1) under visible-light irradiation. The BA3 (contained 9.09% of AgI) exhibited the highest photocatalytic activity and maintained good stability. It could completely inactivate 7.0 x 10(7) CFU/mL of E. coli in 50 min and degrade 80% of OTC-HC1 in 60 min. The enhanced photocatalytic activity of Agl/BiVO4 composites could be ascribed to the lower recombination rate of electron-hole pairs. Meanwhile, radical trapping experiments revealed that the superoxide radical (O-center dot(2)-) and holes (h(+)) were the dominant reactive species in photo disinfection process. Furthermore, the effects of bacterial initial concentration and inorganic anions were also investigated to optimize the photocatalyst for practical application. This study will give a new insight to construct the effective Z-scheme system for bacterial inactivation and organic pollutants degradation. (C) 2017 Elsevier Inc. All rights reserved.