Preparation and Investigation of Photocatalytic Properties of ZnO Nanocrystals: Effect of Operational Parameters and Kinetic Study

Authors: N. Daneshvar, S. Aber, M. S. Seyed Dorraji, A. R. Khataee, M. H. Rasoulifard

Abstract:

ZnO nanocrystals with mean diameter size 14 nm have been prepared by precipitation method, and examined as photocatalyst for the UV-induced degradation of insecticide diazinon as deputy of organic pollutant in aqueous solution. The effects of various parameters, such as illumination time, the amount of photocatalyst, initial pH values and initial concentration of insecticide on the photocatalytic degradation diazinon were investigated to find desired conditions. In this case, the desired parameters were also tested for the treatment of real water containing the insecticide. Photodegradation efficiency of diazinon was compared between commercial and prepared ZnO nanocrystals. The results indicated that UV/ZnO process applying prepared nanocrystalline ZnO offered electrical energy efficiency and quantum yield better than commercial ZnO. The present study, on the base of Langmuir-Hinshelwood mechanism, illustrated a pseudo first-order kinetic model with rate constant of surface reaction equal to 0.209 mg l-1 min-1 and adsorption equilibrium constant of 0.124 l mg-1.

Keywords: Zinc oxide nanopowder, Electricity consumption, Quantum yield, Nanoparticles, Photodegradation, Kinetic model, Insecticide.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1072778

References:

[1] H. Shemer, K. G. Linden, Degradation and by-product formation of diazinon in water during UV and UV/H2O2 treatment, J. Hazard. Mater. B, Vol. 136, 2006, pp. 553-559.
[2] S. sakthivel, B. Neppolian, M. V. Shankar, B. Arabindoo, M. Palanichamy, V. Murugesan, Solar photocatalytic degradation of azo dye comparison of photocatalytic efficiency of ZnO and TiO2, Sol. Energy Mater. Sol. C, Vol. 77, 2003, pp. 65-82.
[3] C. A. K. Gouvea, F. Wypych, S.G. Moraes, N. Duran, N. Nagata, P. Peralta, Semiconductor-assisted photocatalytic degradation of reactive dyes in aqueous solution, Chemosphere, Vol. 40, 2000, pp. 433-440.
[4] C. Lizama, J. Freer, J. Baeza, H. D. Mansilla, Optimized photodegradation of reactive Blue 19 on TiO2 and ZnO suspensions, Catal. Today, Vol. 76, 2002, pp. 235-246.
[5] H. J. Kuhn, S. E. Braslavsky, R. Schmidt, Chemical actinometry, IUPAC technical report, Pure Appl. Chem, Vol. 76, 2004, pp. 2105-2146.
[6] W. K. Choy, W. Chu, The use of oxyhalogen in photocatalytic reaction to remove o-chloroaniline in TiO2 dispersion, Chemosphere, Vol. 66, 2007, pp. 2106-2113.
[7] N. Daneshvar, A. Aleboyeh, A. R. Khataee, The evaluation of electrical energy per order (EEO) for photooxidative decolorization of four textile dye solution by the kinetic model, Chemosphere, Vol. 59, 2005, pp.761- 767.
[8] N. Daneshvar, D. Salari, A. R. Khataee, Photocatalytic degradation of azo dye acid red 14 in water on ZnO as an alternative catalyst to TiO2, J. Photochem. Photobiol. A: Chem., Vol. 162, 2004, pp. 317-322.
[9] R. Comparelli, E. Fanizza, M. L. Curri, P. D. Cozzoli, G. Mascolo, A. Agostiano, UV-induced photocatalytic degradation of azo dyes by organic-capped ZnO nanocrys- tals immobilized onto substrates, Appl. Catal. B: Environ, Vol. 60, 2005, pp. 1-11.
[10] O. Legrini, E. Oliveros, A. M. Braun, Photochemical process for water treatment, Chem. Rev., Vol. 93, 1993, pp. 671-698.
[11] C. Lizama, J. Freer, J. Baeza, H. Mansilla, Optimal photodegradation of reactive blue 9 on TiO2 and ZnO suspension, Catal. Today, Vol. 76, 2002, pp. 235-246.
[12] A.A. Khodja, T. Sehili, J. Pilichowski, P. Boule, Photocatalytic degradation of 2 phenyl-phenol on TiO2 and ZnO in aqueous suspension, J. Photochem. Photobiol. A: Chem., Vol. 141, 2001, pp. 231-239.