Kinetic investigation of nano photocatalytic reaction (ZnO-Ag-Zn) in the degradation of reactive red dye 198.

In this research, a photocatalytic reactor made of quartz was designed and built. Then modified ZnO photocatalysts with different percentages of Ag and Zr were made by combustion method and using the microwave. Photocatalytic experiments showed that nano photocatalysts with a mass ratio of 0.093 Ag and 0.04 Zr are more efficient. The characteristics of this catalyst were evaluated by XRD, SEM, and FT-IR analyses. Then the photocatalytic activities of ZnO-Ag-Zr in the degradation of reactive red dye 198 were investigated and the effective factors such as pH of the solution, amount of catalyst, and initial concentration of the solution were investigated. Experiments showed that the optimal conditions for decolorization of the dye at a concentration of 20 mg/liter are: pH=10 and the amount of catalyst is 0.3 g/l, and in these conditions, the decolorization rate is above 92%. Also, the study of the kinetics of the mentioned reaction showed that the removal rates of Reactive Red 198 dyes are in good agreement with the pseudo-firstorder Longmire-Hinshelwood equation, and therefore, the kinetic parameters were determined using this model. [ABSTRACT FROM AUTHOR]