Article ID Journal Published Year Pages File Type
222441 Journal of Environmental Chemical Engineering 2015 12 Pages PDF
Abstract

•Adsorption onto Sauge was combined to photocatalysis for Cr(VI) removal.•Photocatalysis with new heterojunction system p-CuCo2O4/n-TiO2 under visible light.•Tannery wastewater (2.25 mg L−1 Cr(VI)) was completely treated photocatalytically.•The hybrid process showed its efficiency, 82% removal of 150 mg L−1 initial Cr(VI).

Chrome(VI) removal was investigated by adsorption onto an agricultural farm plant (Sauge) combined to photocatalysis onto the new hetero-system p-CuCo2O4/n-TiO2 in the presence of tartaric acid.In batch configuration, the equilibrium was reached after 3 h. Increasing the initial Cr(VI) concentration increased the adsorption capacity and decreased the efficiency removal and the optimal pH was found to be ∼2. Among the tested equilibrium isotherms, the Langmuir model led to the most accurate fit of experimental data. Adsorption kinetic data followed a pseudo-second order model and the intra-particle diffusion study revealed that the adsorption rate was not controlled by the diffusion step.The photo-reduction of Cr(VI) onto the hetero-system CuCo2O4/TiO2 under visible light was studied to complete the water treatment operation. The optimal photocatalytic performance was found for 25 mg L−1 initial Cr(VI) concentration and pH ∼2. Under these conditions, the hetero-system favored hydrogen formation, with an evolved volume of 1.70 cm3 after 25 min. The contaminated industrial wastewater of tannery containing 2.25 mg L−1 was completely treated photo-catalytically.The hybrid process (adsorption/photocatalysis) was tested and showed its efficiency. For 150 mg L−1 initial amount, removal yield increased from 45% if only adsorption was considered to 82.6% by the hybrid process in less time. Hence, the hybrid process constitutes an eco-friendly approach, since it involves low cost and environmental friendly waste materials for the adsorption step (Sauge) and the hetero-system CuCo2O4/TiO2 allowing photochemical reduction under visible light.

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Physical Sciences and Engineering Chemical Engineering Chemical Engineering (General)
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