Heterogeneous Photocatalytic Mineralization of Azo Dye in Aqueous Solution

摘要

The photocatalytic degradation of azo dye acid orange 7 was studied using different semiconductor photocatalyst such as ZnO, TiO?, ZnS and WO3 in a batch reactor configuration in presence of UV light. ZnO was found to a more efficient photocatalyst in the degradation of the dye compared to other photocatalysts. In the presence of UV/ZnO, illumination was done using a 6 W low pressure mercury vapour lamp. The variables studied include catalyst usage, solution pH and effect of wavelength of incident light on the photocatalytic degradation of the dye. The incident light with wavelength of 254 nm was comparatively more effective than 375 nm light. The degradation rate of acid orange 7 was found to increase linearly with increase in pH and the optimum loading of ZnO was found to be 2.0 g/L. Total organic carbon analysis indicated complete mineralization of dye in aqueous solution.