Effects of KBr and KI on Photocatalytic Degradation of Dye W-7G with Nano-TiO₂ as Catalyst

Figure 4

Adsorption models of W-7G in TiO₂ solution and schematic diagram of the photocatalysis mechanism involving anion radicals: (a) at acidic conditions (pH < pi); (b) at alkaline conditions (pH > pi); (c) radical reaction with dye molecules adsorbed on the surface; (d) radical reaction with halogen ions adsorbed on the surface.

(a)

(b)

(c)

(d)