Photocatalytic degradation of polychlorinated dioxins and polychlorinated biphenyls in aqueous suspensions of semiconductors irradiated with simulated solar light

The complete photocatalytic degradation of two polychlorinated dibenzo-p-dioxins and one polychlorinated biphenyl to CO2 and HCl has been investigated in aerated aqueous suspensions of several semiconductors (TiO2, ZnO, CdS, TiO2/Pt 5% by weight, and Fe2O3) irradiated by simulated solar light. The particular compounds were the 2-chlorodibenzo-p-dioxin (CDD), the 2,7-dichlorodibenzo-p-dioxin (DCDD), and the 3,3'-dichlorobiphenyl (DCB). TiO2 shows the highest photo-activity for the degradation process studied; platinization seems to have little effect. The presence of conduction band electron scavengers such as Ag+ and Fe3+ ions increase the activity of TiO2