[Photocatalytic degradation kinetics of diuron by TiO2 and simulated sunlight]

Photocatalytic degradation kinetics of diuron in aqueous solution was systematically investigated using TiO2 as the photocatalyst. The single-variable-at-a-time (SVAT) method and the central composite design (CCD) based on response surface methodology (RSM) were employed to study the individual and synergistic effects of several classical parameters on photocatalytic efficiencies. Three different parameters, namely TiO2 concentration, pH value and initial temperature of the model pollutant, were found to independently determine the degradation efficiencies. From the SVAT experiments, it could be concluded that neutral solutions were favorable for the degradation of diuron, and the degradation rate increased with the increasing temperature. Moreover, the results from CCD indicated that the optimum degradation conditions were as follows: TiO2 concentration at 2.98 g x L(-1), pH value at 7.78, and temperature at 40 degrees C.