Photocatalytic degradation of diclofenac sodium over the photocatalyst of TiO₂/CFA

A new type of composite photocatalyst TiO₂/CFA was prepared by hybrid slurry procedure. Coal fly ash (CFA) discharged from coal-fired power plant was used as substrate, and the samples were characterized by scanning electron microscope, X-ray diffraction analysis and nitrogen adsorption tests. The impacts of loading amounts on the photocatalytic activity and re-use performance of titania anchored on CFA were evaluated by the photocatalytic degradation reaction of diclofenac sodium solution. The results show that the increase of loading amounts can improve the photocatalytic activity of TiO₂/CFA, but when the loads are too high, superfluous TiO₂ are easy to break away from CFA in the progress of water treatment, which is not favorable for the re-use properties of photocatalyst TiO₂/CFA. In this study, the optimal loading percentage of titania was about 50%, and the photocatalytic degradation efficiency was maintained at above 70% without any decline when the composite photocatalyst was used repeatedly, even in the sixth cycle.