The effect of operational parameters on the photoinduced decoloration of dyes using a hybrid catalyst V2O5/TiO2

The decoloration of three dyes namely Toludine Blue, Safranin Orange and Crystal Violet was studied in the presence of UV radiation using a heterogeneous hybrid catalyst, namely titanium oxide impregnated with vanadium oxide. The advantage of using a hybrid catalyst lies in the fact that the decoloration increased by more than five times as compared to in a neat catalyst. The influence of operational parameters, such as dye concentration, amount of catalyst and pH of the solution were thus determined for dye decoloration using a hybrid catalyst. Rate of photoinduced catalytic decoloration was calculated from the observed absorption changes and the induced effects were explained on a mechanistic model involving the generation of OH radicals which are responsible for the decoloration of dye solution. The kinetic data fitted well to pseudo first order equation and the Langmuir–Hinshelwood model. Dye decoloration was also investigated in the presence of some ions and their role was discussed in terms of chemical reactions.