Photocatalytic activities of AgBr/Y-zeolite in water under visible light irradiation

A novel photocatalytic material was synthesized by dispersion of AgBr (silverbromide) in Y-zeolite. The catalysts were characterized using XRD (X-ray diffraction), UV-Vis spectrophotometry, and ICP-AES analysis. The photocatalytic activity and stability of the synthesized catalysts were evaluated for methyl orange (MO) degradation in aqueous solution in the presence of halogen light or direct sunlight. Three parameters were examined, namely AgBr content in catalysts ([wt%](AgBr)), incident light intensity (I-0) and catalyst loading (W-cat) in reaction suspension. MO degradation was found to follow the zero-order kinetics, and the reaction rate (-dC(t)/dt) could be expressed as -dC(t)/dt= 5.6 x 10(-10) [wt%](AgBr)center dot I-0 center dot W-cat(0.42) in this study. XRD analysis and the cycling runs indicated that AgBr could remain stable and effective after long time irradiation. The results from MO degradation in the presence of methanol or hydrogen peroxide and potassium iodide oxidation demonstrated that AgBr/Y-zeolite catalysts prepared in this study could initiate the photoreduction process. (C) 2009 Elsevier Ltd. All rights reserved.