Synthesis, characterization and catalytic activity of nano size semiconductor metal oxide in a visible light batch slurry photoreactor

Nano size zinc oxide was prepared employing zinc acetate as the precursor solution and aqueous sodium hydroxide as the medium. The formation of pure ZnO was confirmed through FT-IR and powder X-ray diffraction. Surface morphology was characterized by SEM and TEM analysis. The visible photocatalytic behaviour of the synthesized ZnO was tested through the degradation of AB10B. The disappearance of dye molecules followed pseudo-first-order kinetics. The effect of various parameters namely, pH of the medium, catalyst loading, initial dye concentration and kinetics of photo degradation of AB10B was investigated. The rate of degradation was found to be strongly influenced by all above mentioned parameters. The reduction in the chemical oxygen demand (COD) of the degraded aqueous samples revealed a possibility of complete destruction of the organic molecules along with colour removal. Adsorption of AB10B onto ZnO particles was also carried out and experimental data were analysed by model equations such as Langmuir and Freundlich isotherms and it was found that the Langmuir isotherm model best fitted the adsorption data. Kinetic analyses were indicative of the complex nature of the heterogeneous photo catalytic process. The formation of intermediates during the degradation of the dye was monitored by ESI-Mass and HPLC analysis. (C) 2012 Elsevier B.V. All rights reserved.