UV-induced photocatalytic oxidation of an organic dye by prepared nanosized ZnO: Comparison and modeling reaction kinetic

The present work mainly deals with preparation of ZnO, ZnFe2O4 and ZnO-SnO2 nanocrystals using precipitation and co-precipitation method and investigation their photocatalytic activity. Prepared nanocrystals examined as photocatalyst for UV-induced decolorization of Acid Blue 9 (AB9) as deputy of organic pollutant in aqueous solution. The degradation of rate was not so high when the photolysis was carried out in the absence of ZnO and it was negligible in the absence of UV light. We have studied the influence of basic photocatalytic parameters such as pH of solution, amount of ZnO, irradiation time, light intensity and initial concentration of dye on the photodecolorization efficiency of Acid Blue 9. A kinetic model is applied for the photocatalytic oxidation by UV/ZnO system. Experimental results indicated that photocatalytic oxidation process could be explained in terms of the Langmuir-Hinshelwood (L-H) kinetic model. In this work, we also compared photocatalytic activity of prepared zinc oxide nanocrystals with synthesized zinc ferrite and zinc oxide coupled with tin oxide nanocrystals. Our results showed that the UV/photocatalyst process with ZnO-SnO2 as photocatalyst was appropriate as effective method for removal of Acid Blue 9 from solution. In the presence of ZnO-SnO2 nanocrystals as photocatalyst, the electrical energy consumption per order of magnitude (EE/O) and quantum yield were lowest and highest for photocatalytic oxidation of dye, respectively.

Keywords:

Zinc oxide , Nanoparticles , quantum yield , Electrical energy consumption , kinetic