Kinetics of photocatalytic degradation of methylene blue on nanostructured TiO2 coatings created by sol-gel process

Document Type : Original Research Article


1 Department of Materials Engineering, School of Engineering, Yasouj University, Yasouj, Iran

2 Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz, 7134851154, Iran


Sol-gel process was chosen to produce a photocatalytic film to degrade methylene blue. In order to study structural and morphological properties of the coatings, a base sol of TTIP, I-PrOH, and DEA was prepared. Then with addition of 45g/L PEG 2000, 30g/L TiO2 and 15g/L PEG 2000 + 30g/L TiO2, to the base sol, three other sols were produced. The results of this study indicated that substrate can affect photocatalytic behavior of the coatings. Then different parameters (Sol types, number of dip coating cycles, initial concentration, two wavelengths of 265 and 254 nm and pH) of the study were modified and an equation was derived for each parameter. At last, using all the derived equations, a more general equation was calculated to predict the rate of corrosion based on pH, initial concentration of methylene blue, and number of dip coating cycles. A reactor was designed and tested to investigate the effect of continuous degradation. It was realized that the rate of all photocatalytic reactions were inhibited as a result of higher evaporation and decreased exposure time to coating and ultraviolet light.


Main Subjects

1. Sreethawong, T., Ngamsinlapasathian, S., Yoshikawa, S., "Surfactant-aided sol–gel synthesis of mesoporous-assembled TiO2–NiO mixed oxide nanocrystals and their photocatalytic azo dye degradation activity", Chemical engineering journal, Vol. 192, (2012), 292-300.
2. Li, D., Pan, C., "Fabrication and characterization of electrospun TiO2/CuS micro–nano-scaled composite fibers", Progress in Natural Science: Materials International, Vol. 22, No. 1, (2012), 59-63.
3. Zhang, Y. P., Xu, J. J., Sun, Z. H., Li, C. Z., Pan, C. X., "Preparation of graphene and TiO2 layer by layer composite with highly photocatalytic efficiency", Progress in Natural Science: Materials International, Vol. 21, No. 6, (2011), 467- 471.
4. Lai, C.W., Sreekantan, S., San E, P., Krengvirat, W., "Preparation and photoelectrochemical characterization of WO3-loaded TiO2 nanotube arrays via radio frequency sputtering", Electrochimica Acta, Vol. 77, (2012), 128-136.
5. Mathur, S., Kuhn, P., "CVD of titanium oxide coatings: Comparative evaluation of thermal and plasma assisted processes", Surface and Coatings Technology, Vol. 201, No. 3-4, (2006), 807-814.
6. Bessergenev, V. G., Mateus, M. D. C., Vasconcelos, D. A., Mariano, J. F. M. L., Botelho do Rego, A. M., Lange, R., Burkel, E., "TiO2:(Fe, S) thin films prepared from complex precursors by CVD, physical chemical properties, and photocatalysis", International Journal of Photoenergy, Vol. 2012, (2012).
7. Ma, L., Chen, A., Zhang, Z., Lu, J., He, H., Li, C., "In-situ fabrication of CNT/TiO2 interpenetrating network film on nickel substrate by chemical vapour deposition and application in photoassisted water electrolysis", Catalysis Communications, Vol. 21, (2012), 27-31.
8. Tseng, T. K., Lin, Y. S., Chen, Y. J., Chu, H., "A review of photocatalysts prepared by sol-gel method for VOCs removal", International journal of molecular sciences, Vol. 11, No. 6, (2010), 2336-2361.
9. Macwan, D. P., Dave, P. N., Chaturvedi, S., "A review on nano-TiO2 sol–gel type syntheses and its applications", Journal of materials science, Vol. 46, No. 11, (2011), 3669-3686.
10. Hartmann, P., Lee, D. K., Smarsly, B. M., Janek, J., "Mesoporous TiO2: comparison of classical sol− gel and nanoparticle based photoelectrodes for the water splitting reaction", Acs Nano, Vol. 4, No. 6, (2010), 3147-3154.
11. El-Nahass, M. M., Ali, M. H., El-Denglawey, A., "Structural and optical properties of nano-spin coated sol–gel porous TiO2 films", Transactions of Nonferrous Metals Society of China, Vol. 22, No. 12, (2012), 3003-3011.
12. Zhang, T., Oyama, T., Horikoshi, S., Zhao, J., Hidaka, H., Serpone, N., "Assessment and influence of operational parameters on the TiO2 photocatalytic degradation of sodium benzene sulfonate under highly concentrated solar light illumination", Solar Energy, Vol. 71, No. 5, (2001), 305-313.
13. Liang, Y., Wang, H. S., Casalongue, H. S., Chen, Z., Dai, H., "TiO2 nanocrystals grown on graphene as advanced photocatalytic hybrid materials", Nano Research, Vol. 3, No. 10, (2010), 701-705.
14. Alzamani, M., Shokuhfar, A., Eghdam, E., Mastali, S., "Influence of catalyst on structural and morphological properties of TiO2 nanostructured films prepared by sol–gel on glass", Progress in Natural Science: Materials International, Vol. 23, No. 1, (2013), 77-84.
15. Balasubramanian, G., Dionysiou, D. D., Suidan, M. T., Subramanian, V., Baudin, I., Laîné, J. M., "Titania powder modified sol-gel process for photocatalytic applications", Journal of materials science, Vol. 38, No. 4, (2003), 823-831.
16. Chen, Y., Dionysiou, D. D., "A comparative study on physicochemical properties and photocatalytic behavior of macroporous TiO2-P25 composite films and macroporous TiO2 films coated on stainless steel substrate", Applied Catalysis A: General, Vol. 317, No. 1, (2007), 129-137.
17. Chen, Y., Dionysiou, D. D., "Bimodal mesoporous TiO2–P25 composite thick films with high photocatalytic activity and improved structural integrity", Applied Catalysis B: Environmental, Vol. 80, No. 1-2, (2008), 147-155.
18. Kato, K., Tsuzuki, A., Torii, Y., Taoda, H., Kato, T., Butsugan, Y., "Morphology of thin anatase coatings prepared from alkoxide solutions containing organic polymer, affecting the photocatalytic decomposition of aqueous acetic acid", Journal of materials science, Vol. 30, No. 3, (1995), 837-841.
19. Su, Z., Zhang, L., Jiang, F., Hong, M., "Formation of crystalline TiO2 by anodic oxidation of titanium", Progress in Natural Science: Materials International, Vol. 23, No. 3, (2013), 294-301.
20. Huang, W., Lei, M., Huang, H., Chen, J., Chen, H., "Effect of polyethylene glycol on hydrophilic TiO2 films: Porosity-driven superhydrophilicity", Surface and Coatings Technology, Vol. 204, No. 24, (2010), 3954-3961.
21. Fan, S. Q., Li, C. J., Li, C. X., Liu, G. J., Yang, G. J., Zhang, L. Z., "Preliminary study of performance of dye-sensitized solar cell of nano-TiO2 coating deposited by vacuum cold spraying", Materials transactions, Vol. 47, No. 7, (2006), 1703-1709.
22. Bu, S., Jin, Z., Liu, X., Yang, L., Cheng, Z., "Fabrication of TiO2 porous thin films using peg templates and chemistry of the process", Materials Chemistry and Physics, Vol. 88, No. 2-3, (2004), 273-279.
23. Yu, J., Jimmy, C. Y., Ho, W., Jiang, Z., "Effects of calcination temperature on the photocatalytic activity and photo-induced super-hydrophilicity of mesoporous TiO2 thin films", New Journal of Chemistry, Vol. 26, No. 5, (2002), 607-613.
24. Yu, J. G., Yu, H. G., Cheng, B., Zhao, X. J., Yu, J. C., Ho, W. K., "The effect of calcination temperature on the surface microstructure and photocatalytic activity of TiO2 thin films prepared by liquid phase deposition", The Journal of Physical Chemistry B, Vol. 107, No. 50, (2003), 13871-13879.
25. Dariani, R. S., Esmaeili, A., Mortezaali, A., Dehghanpour, S., "Photocatalytic reaction and degradation of methylene blue on TiO2 nano-sized particles", Optik, Vol. 127, No. 18, (2016), 7143-7154.
26. Shakibania, R., "Kinetic Model for Nanocrystalline Anatase to Rutile Polymorphic Transformation", Chemical and biochemical engineering quarterly, Vol. 31, No. 3, (2017), 353-359.
27. Ba-Abbad, M. M., Kadhum, A. A. H., Mohamad, A. B, Takriff, M. S., Sopian, K., Al-Shamali, S. S., "Kinetics transformation of anatase to rutile phase for titanium dioxide nanoparticles prepared by sol-gel method", Materials Science Forum, Vol. 756, (2013), 11-15. Trans Tech Publications.
28. Hanaor, D. A., Sorrell, C. C., "Review of the anatase to rutile phase transformation", Journal of Materials science, Vol. 46, No. 4, (2011), 855-874.
29. Kuo, W. S., Ho, P. H., "Solar photocatalytic decolorization of methylene blue in water", Chemosphere, Vol. 45, No. 1, (2001), 77-83.
30. Lakshmi, S., Renganathan, R., Fujita, S., "Study on TiO2- mediated photocatalytic degradation of methylene blue", Journal of Photochemistry and Photobiology A: Chemistry, Vol. 88, No. 2-3, (1995), 163-167.
31. Houas, A., Lachheb, H., Ksibi, M., Elaloui, E., Guillard, C., Herrmann, J. M., "Photocatalytic degradation pathway of methylene blue in water", Applied Catalysis B: Environmental, Vol. 31, No. 2, (2001), 145-157.
32. Lachheb, H. Puzenat, E., Houas, A., Ksibi, M., Elaloui, E., Guillard, C., Herrmann, J. M., "Photocatalytic degradation of various types of dyes (Alizarin S, Crocein Orange G, Methyl Red, Congo Red, Methylene Blue) in water by UV-irradiated titania", Applied Catalysis B: Environmental, Vol. 39, No. 1, (2002), 75-90.
33. Sohrabi, H., Mozafari, A., Sajjadnejad, M., Tabaian, S. H., Omidvar, H., "Influence of operational parameters on the TiO2 photocatalytic degradation of Methylene blue", Materials Science and Technology, Vol. 32, No. 12, (2016), 1282-1288.
34. Sohrabi, H., Tabaian, S. H., Omidvar, H., Sajjadnejad, M., Mozafari, A., "Synthesis of nanostructured TiO2 coatings by Sol-Gel method: structural and morphological studies", Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, Vol. 46, No. 3, (2016), 414-422.
35. Azároff, L. V., Donahue, R. J., "Laboratory experiments in x-ray crystallography", McGraw-Hill New York, (1969).
36. Eufinger, K., Poelman, D., Poelman, H., De Gryse, R., Marin, G. B., "Effect of microstructure and crystallinity on the photocatalytic activity of TiO2 thin films deposited by dc magnetron sputtering", Journal of Physics D: Applied Physics, Vol. 40, No. 17, (2007), 5232.
37. Cong, S., Xu, Y., "Explaining the high photocatalytic activity of a mixed phase TiO2: a combined effect of O2 and crystallinity", The Journal of Physical Chemistry C, Vol. 115, No. 43, (2011), 21161-21168.
38. Yu, J. C., Yu, J., Ho, W., Jiang, Z., Zhang, L., "Effects of Fdoping on the photocatalytic activity and microstructures of nanocrystalline TiO2 powders", Chemistry of materials, Vol. 14, No. 9, (2002), 3808-3816.
39. Elfanaoui, A., Elhamri, E., Boulkaddat, L., Ihlal, A., Bouabid, K., Laanab, L., Taleb, A., Portier, X., "Optical and structural properties of TiO2 thin films prepared by sol–gel spin coating",International Journal of Hydrogen Energy, Vol. 36, No. 6, (2011), 4130-4133.
40. Brinker, C. J., Hurd, A. J., Schunk, P. R., Frye, G. C., Ashley, C. S., "Review of sol-gel thin film formation", Journal of Non-Crystalline Solids, Vol. 147, (1992), 424-436.
41. Schubert, D. W., Dunkel, T., "Spin coating from a molecular point of view: its concentration regimes, influence of molar mass and distribution", Materials Research Innovations, Vol. 7, No. 5, (2003), 314-321.