Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 32009
Solar Photocatalysis of Methyl Orange Using Multi-Ion Doped TiO2 Catalysts

Authors: Victor R. Thulari, John Akach, Haleden Chiririwa, Aoyi Ochieng


Solar-light activated titanium dioxide photocatalysts were prepared by hydrolysis of titanium (IV) isopropoxide with thiourea, followed by calcinations at 450 °C. The experiments demonstrated that methyl orange in aqueous solutions were successfully degraded under solar light using doped TiO2. The photocatalytic oxidation of a mono azo methyl-orange dye has been investigated in multi ion doped TiO2 and solar light. Solutions were irradiated by solar-light until high removal was achieved. It was found that there was no degradation of methyl orange in the dark and in the absence of TiO2. Varieties of laboratory prepared TiO2 catalysts both un-doped and doped using titanium (IV) isopropoxide and thiourea as a dopant were tested in order to compare their photoreactivity. As a result, it was found that the efficiency of the process strongly depends on the working conditions. The highest degradation rate of methyl orange was obtained at optimum dosage using commercially produced TiO2. Our work focused on laboratory synthesized catalyst and the maximum methyl orange removal was achieved at 81% with catalyst loading of 0.04 g/L, initial pH of 3 and methyl orange concentration of 0.005 g/L using multi-ion doped catalyst. The kinetics of photocatalytic methyl orange dye stuff degradation was found to follow a pseudo-first-order rate law. The presence of the multi-ion dopant (thiourea) enhanced the photoefficiency of the titanium dioxide catalyst.

Keywords: Degradation, kinetics, methyl orange, photocatalysis.

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 988


[1] Carpenter S. R, Caraco N. F., Correll D. L, Howarth R. W, Sharpley A. N, Smith V. H, 1998, Nonpoint pollution of surface waters with phosphorus and nitrogen, Ecological Applications, 8, 559-568.
[2] Weber, J., Stickne, V.C.,1993. Hydrolysis kinetics of reactive blue 19-vinyl sulfone. Water. Research, 27, 63-67.
[3] Guettai, N., Ait Amar H., 2005. Desalination 185, 427–437.
[4] Tang, W. Z., Zhang, Z, Quintana, M.O., Torres, D.F., 1997. TiO2/UV photodegradation of azo dyes in aqueous solutions. Environmental Technology 18, 1-12.
[5] Dai, S., Song, W., Zhuang Y., Yan, H., 1996. Biotechnical treatment of wastewater containing Azo dyes. In: Proceedings of the 4th Mainland–Taiwan Environmental Technology Seminar, Vol. 1 pp. 407–411.
[6] Chung, K.T., Fulk, G.E., Andres, A.W., 1981, Mutagenicity testing of some commonly used dyes. Applied and Environmental Microbiology 42, 641–648.
[7] Al-Ekabi H. A, Ollis, D, 1993. Photocatalytic Purification and Treatment of Water and Air, Elsevier, Amsterdam.
[8] Herrmann J, 1999. Heterogeneous photocatalysis: fundamentals and applications to the removal of various types of aqueous pollutants. Catalyst Today 53, 115–129.
[9] Zeleska A, Grabowska. E, Sobsczak. J.W, Gazda. M, Hupka. J, 2009. Photocatalytic activity of boron-modified TiO2 under visible light: The effect of boron content, calcinations temperature and TiO2 matrix. Applied catalyst B: Environment 89 469-475
[10] Ku Y, Hsieh C-B, 1992, Photocatalytic decomposition of 2,4-dichlorophenol in aqueous TiO2 suspensions, Water Research, Vol 2, Issue 11, 1451-1456.
[11] Bahnemann D, Bockelmann D, Goslich R, 1991, Mechanistic studies of water detoxification in illuminated TiO2 suspensions, Volume 24, Issues 1–4, 564-583.
[12] D'Oliveira J. C, Al-Sayyed G, Pichat P, 1990, Photodegradation of 2- and 3-chlorophenol in titanium dioxide aqueous suspensions, Environ. Sci. Technol, 24, 7, 990–996.
[13] Wang, Z.,Cai, W., Hong, X., Zhao, X., Xu, F., Cai, C.,2005, Applied Catalyst. B: Environmental 57, 223.
[14] Al-Qaradawi S, Salman S. R, 2002, Photocatalytic degradation of methyl orange as a model compound, Journal of Photochemistry and Photobiology A: Chemistry, 148, 1-3, 161-168.
[15] Linder. M, Bahnemann. D, Hirthe. B, Griebler. W.D, in: Stine. W.B, Tanaka. T, Claridge. D.E, 1995. Solar Water Detoxification, Novel TiO2 Powder as Highly Active Photocatalysis, Solar Engineering, American Society of Mechanical Engineers, New York, Book No.H 0932A, 399–408.
[16] Bahnemann D, Bockelmann. D, Goslich. R, Hilgendorff. M, Weichgrebe. D, 1993. Photocatalytic detoxification: novel catalysis, mechanism and solar application, in: D.F. Ollis, H. Al-Ekabi (Eds.), Photocatalytic Purification and Treatment of Water and Air, Trace Metals in the Environment, Elsevier, Amsterdam, pp. 301–319.
[17] Hilgendroff M, Hilgendroff M, Bahnemann D, 1996, Mechanism of photocatalysis: The reductive degradation of tetrachloromethane in aqueous titanium dioxide suspensions, Journal of Advanced Oxidation Technologies, 1, 1, 35–43.
[18] Mills A, Lee. S, 2004. Semiconductor photocatalysis in advanced oxidation processes for water and wastewater treatment. Parsons. S (ed) 137-180
[19] Hoffman. M.R, Martin. ST, Choi. W, Bahnemann. D.W, 1995. Environmental applications of semiconductor photocatalysis. Chemical reviews 95 69-96