Photocatalytic degradation of phenol and chlorinated phenols using nanometer TiO2 thin films

Photocatalytic degradation of phenol, 4-chlorophenol and 2, 4-dichlorophenol was investigated using TiO2 film prepared by sol-gel process. The effects of initial concentration, pH and the addition of H2O2 on the photoactivities of TiO2 thin film were studied. The results indicate that the TiO2 film has much higher photocatalytic activity on the degradation of phenol and chlorinated phenols. The photodegradation rates decrease in the sequence, 2,4-dichlorophenol>4-chlorophenol>phenol. For all of phenol, 4-chlorophenol and 2, 4-dichlorophenol, an increase in the molar influent concentration resulted in a decrease in removal efficiency. The photoactivities are greatly dependent on the solution pH, and it is more effective for phenol and chlorinated phenols to be degraded under neutral condition. It is likely to contribute for the acid-base equilibra on the surface of the nanoparticles. The proper addition of hydrogen peroxide can improve the degradation rate.