Investigation of the antibacterial and photocatalytic properties of the zeolitic nanosized AgBr/TiO2 composites

Zeolite-based Ag/AgBr and Ag/AgBr/TiO2 photocatalysts were prepared by sol-gel and deposition methods and were characterized. Their photocatalytic activities were evaluated by inactivation of Escherichia (E.) coli and the photodegradation of Acid Blue 92 and potassium permanganate. The composites containing Ag/AgBr showed the antibacterial activity in the dark by releasing Ag+ ions into the medium. The results for inactivation of E. coli indicated that Ag/AgBr/TiO2 modified photocatalyst had better antibacterial activity than Ag/AgBr/zeolite, while zeolite and TiO2/zeolite did not show any antibacterial activity under visible light and dark conditions. Photodecolarization rate was affected differently in the presence of H2O2 depending upon the illumination source. Under visible light the photodecolorization rate is decreased while with UV light it is increased initially and then decreased by increasing hydrogen peroxide concentration. A mechanism for KMnO4 photodegradation is proposed. The effects of catalyst concentration, initial dye concentration and temperature were also studied. (c) 2011 Elsevier Ltd. All rights reserved.