Degradation of Alizarine Red-S (A Textiles Dye) by Photocatalysis using ZnO and TiO₂ as Photocatalyst

The objective of this study was to investigate the ability of semiconductors like TiO₂ and ZnO used to remove a hazardous Alizarin red-S a textile dye from aqueous solution. The adsorption of the Alizarin red-S was selected as a reference molecule for the adsorption studies. The experimental results show that TiO₂ and ZnO can remove the Alizarin red-S from wastewater. The factor affecting rate process involved in the removal of dye for initial dye concentration, effect of various process parameters like initial dye concentration, contact time, dose of catalyst and pH. The adsorption rate data were analyzed using the pseudo first order of kinetics of Lagergren and Pseudo second order model to determine adsorption rate constant. The optimum contact time was fixed at 120 minutes for both TiO₂ and ZnO. The well known Freundlich and Langmuir isotherm equation were applied for the equilibrium. Beside the above the semiconducting materials have also been irradiated with Alizarin red-S before and after studied for SEM, EDX and XRD.