Photoreduction of Potassium Dichromate in Aqueous Solution using Cobalt doped ZnO Nanoparticles

Co-doped ZnO nanoparticles with different Cobalt contents were prepared by direct precipitation method. The materials were characterized by XRD, SEM and TEM techniques. The XRD results indicated that the particle size of pure ZnO and Co-doped ZnO is about 30-45nm. The toxic Cr(VI) in industrial wastewaters can be removed by a reduction from Cr(VI) to Cr(III). The reduction of Cr(VI) to Cr(III) can be achieved by a photocatalytic process. The effect of Co loading on the photocatalytic activity of Co-doped ZnO in the reduction of Cr(VΙ) was studied and the results are compared with the pure ZnO. The results showed that the rate of photoreduction of Cr(VΙ) over Co-doped ZnO is much higher as compared to that of pure ZnO. The photocatalytic reaction were carried out under UV radiation towards the reduction of Cr(VI) by varying different parameters such as irradiation time, pH of the solution, catalyst amount and substrate concentration.