Photocatalytic Decolorization of Methyl Orange by Silica-Supported TiO2 Composites

Document Type: Research Paper


Chemical Engineering Department, University of Mohaghegh Ardabili, P.O. Box 56199-11367, Ardabil, Iran.


Immobilization of TiO2 on silica gel has been proposed to enable easy separation of the catalyst in aqueous systems after photocatalytic reaction. Our simple synthesizing method reduces production cost, and the photocatalyst could find economical application in wastewater treatment. Silica-supported TiO2 composites were prepared by molten salt method at 500, 600 and 700 °C for 60 min. The obtained samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), diffuse reflectance spectroscopy and X-ray fluorescence. SEM results showed a heterogeneous surface covered with spherical particles. According to XRD findings, the only phase of the prepared TiO2/SG nanocomposites at all temperatures was pure anatase. The average crystallite size of anatase was roughly 25, 42, 44 and 53 nm for nanocomposites prepared at 550, 600, 700 and 800 °C, respectively. The samples taken at 500 and 600 ºC showed a band gap value of 2.98 eV, and for sample synthesized at 700 ºC the band gap was 2.95 eV. The decolorization activity has been evaluated by Methyl orange (MO) oxidation in liquid phase. The results showed that the sample obtained at 700 °C had the highest photocatalytic decolorization efficiency activity, and the sample prepared at 500 °C had the lowest. The decolorization activity of photocatalyst prepared at 700 °C did not change during stability experiment.


1. López-Muñoz MJ, van Grieken R, Aguado J, Marugán J. Role of the support on the activity of silica-supported TiO2 photocatalysts: structure of the TiO2/SBA-15 photocatalysts. Catalysis Today. 15;101(3):307-14.

2. Di Paola A, Cufalo G, Addamo M, Bellardita M, Campostrini R, Ischia M, Ceccato R, Palmisano L. Photocatalytic activity of nanocrystalline TiO2 (brookite, rutile and brookite-based) powders prepared by thermohydrolysis of TiCl4 in aqueous chloride solutions. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2008:317(1):366-76.

3. Ghorbanpour M, Lotfiman S. Solid-state immobilisation of titanium dioxide nanoparticles onto nanoclay. Micro & Nano Letters. 2016; 11(11):684-7.

4. Ghorbanpour M, Falamaki C. Micro energy dispersive x-ray fluorescence as a powerful complementary technique for the analysis of bimetallic Au/Ag/glass nanolayer composites used in surface plasmon resonance sensors. Applied optics. 2012;51(32):7733-8.

5. Wang YM, Liu SW, Xiu Z, Jiao XB, Cui XP, Pan J. Preparation and photocatalytic properties of silica gel-supported TiO2. Materials Letters. 2006;60(7):974-8.

6. Pucher P, Benmami M, Azouani R, Krammer G, Chhor K, Bocquet JF, Kanaev AV. Nano-TiO2 sols immobilized on porous silica as new efficient photocatalyst. Applied Catalysis A: General. 2007;332(2):297-303.

7. Ren S, Zhao X, Zhao L, Yuan M, Yu Y, Guo Y, Wang Z. Preparation of porous TiO2/silica composites without any surfactants. Journal of Solid State Chemistry. 2009;182(2):312-6.

8. Pouraboulghasem H, Ghorbanpour M, Shayegh R, Lotfiman S. Synthesis, characterization and antimicrobial activity of alkaline ion-exchanged ZnO/bentonite nanocomposites. Journal of Central South University. 2016;23(4):787-92.

9. Lotfiman S, Ghorbanpour M. Antimicrobial activity of ZnO/silica gel nanocomposites prepared by a simple and fast solid-state method. Surface and Coatings Technology. 2017;310:129-33.

10. Pourabolghasem H, Ghorbanpour M, Shayegh R. Antibacterial Activity of Copper-doped Montmorillonite Nanocomposites Prepared by Alkaline Ion Exchange Method. Journal of Physical Science. 2016;27(2):1-12.

11. Ghorbanpour, M, Moghimi, M and Lotfiman, S. Silica-Supported Copper Oxide Nanoleaf with Antimicrobial Activity Against Escherichia Coli. Journal of Water and Environmental Nanotechnology. 2017;2(2): 112-117.

12. Periyat P, Baiju KV, Mukundan P, Pillai PK, Warrier KG. High temperature stable mesoporous anatase TiO2 photocatalyst achieved by silica addition. Applied Catalysis A: General. 2008;349(1):13-9.

13. Hadjltaief HB, Zina MB, Galvez ME, Da Costa P. Photocatalytic degradation of methyl green dye in aqueous solution over natural clay-supported ZnO–TiO2 catalysts. Journal of Photochemistry and Photobiology A: Chemistry. 2016;315:25-33.

14. Ding Z, Hu X, Lu GQ, Yue PL, Greenfield PF. Novel silica gel supported TiO2 photocatalyst synthesized by CVD method. Langmuir. 2000;16(15):6216-22.

15. Roy B, Ahrenkiel SP, Fuierer PA. Controlling the size and morphology of TiO2 powder by molten and solid salt synthesis. Journal of the American Ceramic Society. 2008;91(8):2455-63.

16. Reddy MV, Jose R, Teng TH, Chowdari BV, Ramakrishna S. Preparation and electrochemical studies of electrospun TiO2 nanofibers and molten salt method nanoparticles. Electrochimica Acta. 2010;55(9):3109-17.

17. Chen Y, Wang K, Lou L. Photodegradation of dye pollutants on silica gel supported TiO2 particles under visible light irradiation. Journal of Photochemistry and Photobiology A: Chemistry. 2004;163(1):281-7.

18. Van Grieken R, Aguado J, Lopez-Munoz MJ, Marugán J. Synthesis of size-controlled silica-supported TiO2 photocatalysts. Journal of Photochemistry and Photobiology A: Chemistry. 2002;148(1):315-22.

19. Marugán J, Hufschmidt D, Sagawe G, Selzer V, Bahnemann D. Optical density and photonic efficiency of silica-supported TiO2 photocatalysts. Water research. 2006;40(4):833-9.

20. Payami R, Ghorbanpour M, Jadid AP. Antibacterial silver-doped bioactive silica gel production using molten salt method. Journal of Nanostructure in Chemistry. 2016;6(3): 215-221.

21. Ghorbanpour M, Falamaki C. A novel method for the fabrication of ATPES silanized SPR sensor chips: Exclusion of Cr or Ti intermediate layers and optimization of optical/adherence properties. Applied Surface Science. 2014;301: 544-50.

22. Ghorbanpour, M and Falamaki, C. A novel method for the production of highly adherent Au layers on glass substrates used in surface plasmon resonance analysis: substitution of Cr or Ti intermediate layers with Ag layer followed by an optimal annealing treatment. Journal of Nanostructure in Chemistry. 2013;3(1), 1-7 .

23. Ghorbanpour, M. Fabrication of a New Amine Functionalised Bi-layered Gold/Silver SPR Sensor Chip. Journal of Physical Science. 2015;26(2): 1–10.