Photodegradation of Methyl Orange Over CdS–TiO2/L-zeolite Composite Photocatalyst

A stable and active composite photocatalyst CdS–TiO2/L-zeolite has been synthesized through sol–gel method. The composite photocatalyst exhibits enhanced light harvesting in visible region indicating the improved photoresponsive ability because of CdS dopant. Photocatalytic conditions, such as the doping quantity of CdS, the concentration of photocatalyst, initial pH values and concentrations of methyl orange solutions have been systematically studied to obtain the highest photocatalytic efficiency. Photocatalytic kinetics of the composite photocatalyst is proved to conform to the first-order equation. The mechanism of the photocatalytic process is proposed in this work. L-zeolite support and CdS dopant could prevent the undesired electron/hole recombination and promote charge separation aiding for the continuous generation of active radicals. The novel composite photocatalyst shows good promise for applications in degrading environmental pollutants.