Efficiency of various semiconductor catalysts for photodegradation of Safranin-T

Semiconductor photocatalysis often leads to partial or complete mineralization of organic pollutants. In this study, photocatalytic degradation of Safranin-T, a hazardous textile dye, has been investigated using various semiconductors such as titanium dioxide (TiO ₂), zinc oxide (ZnO), bismuth oxide (Bi ₂O ₃), cerium oxide (CeO ₂), yttrium oxide (Y ₂O ₃), and zirconium oxide (ZrO ₂). The experiments were carried out by irradiating the aqueous solution of Safranin-T containing photocatalysts with UVand air. Maximum decolorization of Safranin-T occurred with TiO ₂ (99.8%), followed by ZnO (80.3%), Bi ₂O ₃ (57.1%), CeO ₂ (13.1%), Y ₂O ₃ (12.2%), and ZrO ₂ (10.2%). The rate of photocatalytic degradation varied with increasing concentration of Safranin-T. The equilibrium degradation data of Safranin-T by TiO ₂ and ZnO were fitted to the Langmuir and Freundlich isothermmodels. The Freundlich and Langmuir model showed satisfactory fit to the equilibrium degradation data for TiO ₂ and ZnO, respectively. Photocatalytic degradation of Safranin-T followed pseudo second-order kinetics.