Photocatalytic Reduction of Chromium (VI) in a Typical Hides and Skin Industrial Wastewatwer using Zno/γ-Al2o3 Photocatalyst under Visible LIGHT

Abstract

Photocatalysis is an advanced oxidation process that can degrade and mineralize organic pollutants in wastewater to carbon dioxide and water which was employed in this study. Tannery effluent was treated via batch photoreduction using Zinc oxide photocatalyst supported on y-Al2O3 and irradiated under visible light at the ambient condition of temperature. Zinc oxide obtained from Zinc ore and y-Al2O3 prepared from local kaolin were used to synthesize the ZnO/y-Al2O3. The synthesized photocatalyst was characterized by Brunnaer Emmett Teller (BET), X-ray Diffraction Spectroscopy (XRD), Scanning Electron Microscope (SEM), and X-ray Fluorescence (XRF). The result of the analysis reveals that the total surface area, total pore volume and mean pore size of the photocatalyst prepared were 65.452 m2g-1, 0.151 cm3g-1 and 9.892 nm respectively. The photocatalyst is crystalline and the SEM image shows the presence of pores. The ZnO/y-Al2O3 was used as a photocatalyst to reduce Chromium (VI) of a typical tannery wastewater. 96% reduction of 20 mg/L of Cr (VI) was achieved at 60 min, pH of 3, and a photocatalyst dosage of 2.5 g/L under visible light of 400 W intensity. The kinetic study revealed that the photoreduction was fitted into the pseudo-first-order Lagmuir-Hinshelwood kinetic model. This research demonstrated that ZnO/y-Al2O3 photocatalyst was effective in the photoreduction of the selected response for the treatment of tannery wastewater.