Effect of hydrogen peroxide, periodate and persulfate on photocatalysis of 2-chlorobiphenyl in aqueous TiO2 suspensions

Decomposition of 2-chlorobiphenyl (2-CB) in the systems of UV/TiO2, UV/oxidant and UV/TiO2/oxidant (i.e. H2O2, S2O82− and IO4−), were investigated. The addition of inorganic oxidants to the UV/TiO2 system showed no rate-enhancing effects for the degradation of 2-CB with oxidant concentration of 10−3 and 10−2 M and TiO2 concentration of 25 mg/l. The negative effect of oxidants on the heterogeneous oxidation was demonstrated. Homogeneous photooxidation seems to dominate over the parallel heterogeneous process when both TiO2 and oxidants are present.