Process Development for Photocatalytic Degradation of Reactive Dyes in Wastewater

Advanced oxidation processes (AOPs) are widely used for the removal of recalcitrant organic constituents from industrial and municipal wastewater. This study mainly focused the use of TiO2 and ZnO catalysts for removal of textile dyes. Synthesis of TiO2 and ZnO photo catalysts was done by sol-gel method. These catalysts were used to obtain enhanced photo catalytic action and were coated on glass beads to improve the photo catalytic activity. The synthesized beads were examined using SEM, FTIR and XRD. Synthesized photocatalysts were examined extensively for their photocatalytic activities with Reactive Orange(RO), Reactive Blue(RB), Textile industry Effluent (TIE) and mixture of dyes (RO+RB, RO+RB +TIE) at various concentrations (50ppm, 100ppm). The photocatalytic degradation of RO, RB, TIE, RO+RB and RO+RB +TIE dyes solution (100mg/L and 50mg/L) using TiO2 and ZnO were investigated under UV light irradiation (λ=254nm). Photocatalytic studies revealed that the TiO2 has shown much higher photocatalytic activity than the ZnO catalyst. The photocatalytic activity of the TiO2 catalyst follows the order: Reactive Orange of 50 ppm (80.98%) > Reactive Blue dye of 50 ppm (77.17%)> Reactive Orange dye of 100 ppm (74.98)>Reactive blue of 100 ppm (72%). The photocatalytic activity of the ZnO catalyst follows the order: Reactive Orange of 50 ppm (75.12%) > Reactive Blue dye of 50 ppm (73.98%)> Reactive Blue dye of 100 ppm (71%)>Reactive Orange of 100 ppm (70%).