Photocatalytic degradation of an azo dye Sunset Yellow under UV-A light using TiO_2/CAC composite catalysts

摘要

The photocatalytic activity and the promoting effect of titania (TiO_2) by commercial activated carbon (CAC) for removing the pollutant in wastewater were investigated. The TiO_2/CAC composite photocatalysts with various ratios of CAC to TiO_2 were prepared by sol-gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area measurement methods. The photocatalytic activity of TiO_2/CAC was investigated for the degradation of Sunset Yellow (SY) in aqueous solution using UV-A light. The TiO_2/CAC is found to be more efficient than prepared TiO_2 and TiO_2-P25 at pH 7 for the mineralization of SY. The synergism between TiO_2 and CAC may increase the catalytic activity. The effects of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on photo mineralization of SY have been analyzed. The mineralization of SY has been confirmed by COD measurements. The catalyst is found to be reusable.