Kinetics of photocatalytic oxidation of trace organic compounds over titanium dioxide

The 350 nm UV-illuminated slurries of titanium dioxide were used to study the photocatalyzed degradation kinetics of dissolved organic carbon (DOC) as water contaminants. The initial rate data were well described by the Langmuir-Hinshelwood rate equation and the simplified Langmuir-Hinshelwood rate equation (i.e., ln(C0/C)=K't). The latter will be more easily used for predicting the degradation of DOC concentratio- n at various elapsed times. In different DOC initial concentrations the apparent first-order rate constant (K') decreased and half-life increased when the initial DOC concentration decreased. The Langmuir-Hinshe- lwood rate form will be the most convenient to describe the oxidation rate of DOC in the drinking water resources, if it is as brief as v=kKC.