TiO 2 /clay as a heterogeneous catalyst in photocatalytic/photochemical oxidation of anionic reactive blue 19

A TiO 2-coated Tunisian clay (TiO 2-clay) was synthesized by a typical impregnation method. The physicochemical characterization points to a successful impregnation of titania on the clay surface. The activity of this structured catalyst was studied in the photocatalytic/photochemical oxidation of anionic reactive blue 19 (RB 19). The effect of UVA and solar irradiation (UV-solar) was studied at room temperature. TiO 2-clay demonstrated an effective degradation of RB 19 under both types of irradiation. Moreover, in this study, the effects of various oxidants such as hydrogen peroxide (H 2 O 2), potassium peroxodisulfate (K 2 S 2 O 8) and sodium carbonate (Na 2 CO 3) were thoroughly investigated. H 2 O 2 was a promising oxidant for promoting RB 19 degradation under UV A. The kinetics of discoloration of RB 19 followed a pseudo-first-order rate law. We can remark that 20 min of UV irradiation was enough to achieve 100% discoloration of the aqueous solution. However, under UV-Vis, HPLC and chemical oxygen demand measurements indicated, that a longer reaction time (of around 45 min) was required for achieving the complete dye mineralization. The findings clearly demonstrated the applicability of this TiO 2 /clay catalyst for the photocatalytic oxidation of RB 19. ª 2014 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (creativecommons.org/licenses/by-nc-nd/3.0/).