The removal of Hexavalent chromium; (Cr (VI)) by ZnO/LECA as a nano photocatalyst using full factorial experimental design

Document Type : Original Research Paper


1 1 Department of Chemical Engineering, Jundi-Shapur University of Technology, Dezful, Iran 2 Jundi-Shapur research institute, Dezful, Iran

2 Department of chemistry, Faculty of Science, Payamenoor University, Tehran, Iran.



In this research, a synthesized nano photocatalyst was prepared by supporting
ZnO nanoparticle on Lightweight expanded clay aggregate (LECA). The catalyst
was synthesized by the co-precipitation method. The SEM, FT-IR, and XRD tests
were used to characterize ZnO/LECA, which was employed for photocatalytic
removal of Cr (VI) from an aqueous solution in a batch photoreactor. The full
factorial experimental design (FFD) was used for the statistical analysis of data.
The influence of catalyst amounts, pH, and initial concentration of Cr (VI) was
investigated on the reduction of Cr (VI) to Cr (III). The number of active sites was
increased with an increase in the concentration of catalyst to some extent. Also,
the selection of other factors in the optimized amount was important. The optimal
conditions were obtained at 0.75 g/l of photocatalyst, pH at 5 and 20 mg/l of
Cr(VI). The experimental and predicted reduction efficiency by FFD at optimal
conditions were 97.6 and 96.18%, respectively. The comparison of experimental
and predicted data showed a good agreement between them.