PHOTOCATALYTIC DEGRADATION OF MULTIPLE CHLOROPHENOLS AS SIMULATED ENVIRONMENTAL POLLUTANTS IN TiO2/H3PW12O40/AG COMPOSITE FILM SYSTEM

Photocatalytic degradation of chlorophenols (CPs) has been attracting an increasing attention lately. In the paper, TiO2/H3PW12O40/Ag composite film was prepared by sol-gel method with programmed heating hydrothermal technology and spin coating technique to treat CPs. Direct photolysis of five CPs was performed according to the pseudo-first-order kinetics model, in which the photolysis rate of PCP was faster than that of the others under the simulated solar light. The results of mineralization indicated that the aromatic ring in PCP was difficult to be broken down via direct photolysis. By TiO2/H3PW12O40/Ag composite film, photocatalytic degradation efficiency elevated due to the enhancement of the quantum efficiency and visible-light absorption in comparison with direct photolysis as well as other reaction systems (TiO2/H3PW12O40 film and TiO2 film), and the mineralization of PCP increased to 75.70%. The initial degradation rate (r(0)) was in the following order as PCP (0.158 mg.L-1.min(-1)) > 4-CP (0.144 mg.L-1.min(-1)) > 2,4-DCP (0.014 mg.L-1.min(-1)) > 2,4,6-TCP (0.047 mg.L-1.min(-1)) > 2-CP (0.038 mg.L-1.min(-1)), confirming TiO2/H3PW12O40/Ag composite film as new catalyst to be more effective at removing for CPs.