ABSTRACT
In both aqueous and nonaqueous suspensions, the key issue governing the efficiency of photocatalytic oxidative degradation is minimizing electron-hole recombination by maximizing the rate of interfacial electron transfer to capture the photogenerated electron and/or hole. A rigorous treatment of the kinetics involved in the photocatalyzed oxidations of organic substrates on an irradiated semiconductor under a variety of conditions has recently examined whether it was possible to delineate surface vs solution bulk reactions. The proportion of solute existing in such multilayers — relative to those in a surface monolayer or in the bulk solution — will depend on the relative magnitudes of the respective free energy. An interesting aspect of water treatment is that chlorine has virtually no effect on the photocatalytic treatment. Monoaromatics are the pollutants whose degradation by photocatalysis has been the most investigated. The extent of adsorption by the pollutant should contribute to the photocatalytic degradation rate, at least for adsorbed species that are reactive.
