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 CO 2 and HC1 has been investigated in aerated aqueous suspensions of several semiconductors (TiO 2 , ZnO, CdS, TiO 2 Pt 5% by weight, and Fe 2 O 3 ) 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). TiO 2 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 Fe 3+ ions increase the activity of TiO 2 .