Optimization of Photocatalytic Decolourization of Methyl Green Dye Using Commercial Zinc Oxide as catalyst

This study describes the results for series of experiments on photocatalytic decolourization of methyl green dye from aqueous solution in the presence of commercial ZnO suspension. The photocatalytic decolourization has been studied as a function of initial dye concentration, best dose of ZnO, initial pH of aqueous solution, and temperature by regular intervals from experiments. The decolourization of methyl green dye process was found to follow pseudo-first order kinetics with the use of artificial UV (A) light sources. The optimum dye and catalyst concentration was measured and found equal to be 50 ppm and 700 mg/ 200 mL-1 respectively. The best value of pH for the photocatalytic decolourization of methyl green dye in the presence of ZnO suspension is pH 5.4. The Photocatalytic decolourization reaction of dye was endothermic and found the rate of reaction increased with increasing temperature. Arrhenius plot obtains that the activation energy for this reaction is equal to 24. 914 kJ mol-1, this value is small that beyond to be associated with the transport of photoelectrons through the catalyst to the adsorbed oxygen on the surface.