A novel, simple and simultaneous synthesis-immobilization of nano ZnO on perlite (nZnO-P) as a photocatalyst for photocatalytic degradation of Acid orange 7 (AO7) in aqueous solution was investigated. The effect of operational parameters such as initial dye concentration, initial pH, flow rate, photocatalyst granule size, temperature and the kinetic of the removal of AO7 in terms of the Langmuir-Hinshelwood model in a designed semi batch packed bed photoreactor connected to an on-line sampling UV-Vis spectrophotometer was studied. The results showed that AO7 removal efficiency increased with nZnO-P using the designed setup and the proposed photocatalyst was more efficient than TiO2 as a standard catalyst. Our results confirmed the pseudo-first-order kinetics model. The values of the adsorption equilibrium constant, KAO7, the kinetic rate constant of surface reaction, kc, and the activation energy (Ea) were found to be 0.57 (mg.l−1)−1, 0.41 mg.l−1.min−1 and 11.44 kJ/mol, respectively.
2. Kandavelu, V., Katien, H. & Thampi, R. (2004). Photocatalytic degradation of isothiazolin-3-ons in water and emulsion paints containing nanocrystalline TiO2 and ZnO catalysts. Appl. Catal. B: Environ., 48(2), 101-111. DOI: 10.1016/j. apcatb.2003.09.022.
3. Khodja, A.A., Sehili, T., Pilichowski, J. & Boule, P. (2001). Photocatalytic degradation of 2-phenylphenol on TiO2 and ZnO in aqueous suspension. J. Photochem. Photobiol. A: Chem., 141(2-3), 231-239. DOI: 10.1016/S1010-6030(01)00423-3.
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