Photocatalytic Water Purification

@Photo-assisted catalytic degradation of polluting substances in aqueous Ti0₂ suspension and its application to water treatnent were reviewed on the basis of the results obtained from our laboratory. Fundamental mechanism for the generation of photocatalytic activity and characteristics of Ti0₂ crystal specifically for photocatalysis were mentioned in the first sections. Several methods of accelerating the photocatalytic degradation were presented, which include surface modification of Ti0₂ and hybridization with H₂0₂ and ozonation. Degradation processes of volatile organochlorine compounds, pesticides, and other organic and inorganic compounds were discussed with regard to disappearance and Ti0₂ removal rates, degradation pathway, and factors influencing the degradation reaction. Inunobilization of Ti0₂, recovery and reuse of Ti0₂ powder, and utilization of sunlight were mentioned to demonstrate the present situation of practical application and commercialization.