[Kinetic study on photocatalytic degradation of p-chlorobenzoate at different light intensities]

Kinetics of photocatalytic degradation were investigated at different light intensities using para-chlorobenzoate as a model pollutant. It was experimentally found that the Langmuir-Hinshelwood model could satisfactorily describe all the kinetic processes. However, the two crucial parameters involved in the L-H model were dependent of the incident light intensity. With elevated light intensity, the rate constant, kr, increased whereas the apparent adsorption constant, Ks, decreased. Grossly, both kr and Ks-1 were correlated with the light intensity in a power law. The experimental discovery implies that the photonic efficiency would be much deteriorated with increased radiation intensity although the reaction rate can be enhanced. Applying mild light intensity might be one of the critical strategies in photocatalytic reactor design to improve the photonic efficiency.