The influence of metal ions on the photocatalytic oxidation of 2-chlorophenol in aqueous titanium dioxide suspensions

This study investigated the effect of metal ions,such as Fe3+, Cu2+, Ni2+, Cr3+ and Zn2+, on the photocatalytic oxidation of 2-chlorophenol with illum ination of 254 nm and 365 nm UV lights. Different metal ions have individua l reduction potentials, and hence, their abilities to capture electrons als o differ; the rates of 2-chlorophenol decomposition vary as well. This stud y was made to explore the relationships between the reduction potentials of different metal ions and their photocatalytic rates of 2-chlorophenol. Res ults show that when the reduction potential is greater than zero, regardles s of illumination wavelength, the reaction rate increases with increasing r eduction potentials of the metal ions. When the reduction potential is less than zero, the reaction rates are about the same for illumination of 365 n m or 254 nm UV lights.