AgBr-ZnO - An efficient nano-photocatalyst for the mineralization of Acid Black 1 with UV light

The AgBr loaded ZnO (AgBr-ZnO) was successfully synthesized by simultaneous precipitation of zinc oxalate and AgBr and calcination of the mixed precipitate at 400 degrees C for 12 h. The catalyst was characterized by Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD), scanning electron microscope (SEM) images, energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), cyclic voltammetry measurements (CV), X-ray photoelectron spectroscopy (XPS), and BET surface area measurement. XPS analysis reveals that Ag in the catalyst is present in the form of Ag+. Crystalline size of AgBr-ZnO is found to be 51.36 nm which is larger than the size of prepared ZnO (30.12 nm). The photocatalytic activity of AgBr-ZnO was investigated for the degradation of Acid Black (AB 1) in aqueous solution using UV light. AgBr-ZnO is found to be more efficient than commercial ZnO and prepared ZnO at pH 12 for the mineralization of Acid Black 1. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization have been analyzed. The intermediates formed during the photodegradation were identified by GC-MS analysis. The mineralization of Acid Black 1 has also been confirmed by COD measurements. The catalyst is found to be reusable. (C) 2011 Elsevier B.V. All rights reserved.