TiO2 photocatalytic degradation of 4-chlorobiphenyl as affected by solvents and surfactants

Purpose TiO2 photocatalytic degradation of 4-chlorobiphenyl (PCB3) in aqueous solution under UV irradiation was investigated as affected by different environmental factors, including initial PCB3 concentration, TiO2 content, UV intensity, H2O2 concentration, cosolvents, and surfactants. Materials and methods The solution of PCB3 with TiO2 was irradiated by medium mercury lamp. The concentration of PCB3 and intermediates was analyzed by GC-mu ECD and GC-MS. The values of point charge and bond length were also calculated with ChemOffice 2004 (Mopac unit). Results and discussion Photocatalysis was very effective for PCB3 removal, and the degradation kinetics were fitted with a pseudo-first order reaction model. PCB3 was efficiently degraded in the presence of acetone and acetonitrile, but was completely inhibited with other examined cosolvents. HPCD and Tween80 also inhibited the degradation rate of PCB3, while Brij35 slightly decreased the degradation rate of PCB3 at first, and then increased. The reaction mechanism occurred principally by hydroxyl radicals involving the participation of holes and superoxide anion oxidation. A possible photocatalytic degradation pathway of PCB3 was proposed based on the identified reaction intermediates as well as computer simulation. Conclusions The photocatalytic approach could be successfully applied to degrade PCB3, and cosolvents and surfactants significantly influenced its degradation kinetics.