Mohammad A Behnajady - Department of Applied Chemistry, Islamic Azad University, Tabriz Branch
Nasser Modirshahla
Mohammad Shokri
Nafiseh Mansoriieh

Chromium is generated from various industrial processes. The photocatalytic reduction of Cr(VI) to Cr(III) by immobilized ZnO on glass has been investigated in a laboratory scale photoreactor. In this study, the photoreduction of Cr(VI) on the surface of the immobilized ZnO catalyst was studied as a function of pH of the solution, initial Cr(VI) concentration and ultraviolet light intensity. Results show that reduction rate decreases with increasing initial concentration of Cr(VI) and initial pH of solution but increases with increasing UV-light intensity. Pseudo-first order kinetics was observed for photoreduction of Cr(VI) at different operational conditions. With nonlinear regression analysis a mathematical kinetic model was developed for pseudo-first order constant (kap) as a function of operational parameters.

Cr(VI); Immobilized ZnO; Kinetic model; Photocatalyst; Photoreduction