DOI QR코드

DOI QR Code

Degradation of a Refractory Organic Contaminant by Photocatalytic Systems

  • Kim, Il-Kyu (Department of Environmental Engineering, Pukyong National University)
  • Received : 2014.09.23
  • Accepted : 2014.10.28
  • Published : 2014.12.31

Abstract

In this research, the photocatalytic degradation of benzothiophene in $TiO_2$ aqueous suspension has been studied. $TiO_2$ photocatalysts are prepared by a sol-gel method. The dominant anatase-structure on $TiO_2$ particles is observed after calcining the $TiO_2$ gel at $500^{\circ}C$ for 1hr. Photocatalysts with various transition metals (Nd, Pd and Pt) loading are tested to evaluate the effect of transition metal impurities on photodegradation. The photocatalytic degradation in most cases follows first-order kinetics. The maximum photodegradation efficiency is obtained with $TiO_2$ dosage of 0.4g/L. The photodegradation efficiency with Pt-$TiO_2$ is higher than pure $TiO_2$ powder. The optimal content value of Pt is 0.5wt.%. Also we investigate the applicability of $H_2O_2$ to increase the efficiency of the $TiO_2$ photocatalytic degradation of benzothiophene. The optimal concentration of $H_2O_2$ is 0.05. The effect of pH is investigated; we obtain the maximum photodegradation efficiency at pH 9. Hydroxy-benzothiophenes and dihydroxy-benzothiophenes are identified as reaction intermediates. It is proposed that benzothiophene is oxidized by OH radical to sequentially form hydroxyl-benzothiophenes, dihydroxybenzothiophenes, and benzothiophenedione.

Keywords

References

  1. Aaron Wold, 1992, Photocatalytic Properties of $TiO_2$. Chem. Mater., 5, p.280-283.
  2. J. Kumar and A. Bansal, 2012, Photodegradation of amaranth in aqueous solution catalyzed by immobilized nanoparticles of titanium dioxide, Int. J. Environ. Sci. Technol., 9, p.479-484. https://doi.org/10.1007/s13762-012-0064-4
  3. J. Palau, M. Colomer, Josep M. Penya-Roja, Vicente Martinez-Soria, 2012, Photodegradation of Toluene, m-Xylene, and n-Butyl Acetate and Their Mixtures over $TiO_2$ Catalyst on Glass Fibers, Ind. Eng. Chem. Res., 51, p.5986-5994. https://doi.org/10.1021/ie300357x
  4. S. Cong, Y. Xu, 2011, Enhanced sorption and photodegradation of chlorophenol over fluoride-loaded $TiO_2$, Journal of Hazardous Materials, 192, p.485-489. https://doi.org/10.1016/j.jhazmat.2011.05.043
  5. T. Luenloi, B. Chalermsinsuwan, T. Sreethawong, N. Hinchiranan, 2011, Photodegradation of phenol catalyzed by $TiO_2$ Coated on acrylic sheets: Kinetics and factorial design analysis, Desalination, 274, p.192-199. https://doi.org/10.1016/j.desal.2011.02.011
  6. P. S. Yap, T. T. Lim, M. Lim, M. Srinivasan, 2010, Synthesis and characterization of nitrogen-doped $TiO_2$/AC composite for the adsorption-Photocatalytic degradation of aqueous bisphenol-A using solar light, Catalysis Today, 151, p.8-13. https://doi.org/10.1016/j.cattod.2010.01.012
  7. C. Chen, P. Lei, H. Ji, W. H. Ma, J. C. Zhou, 2004, Photocatalysis by titanium dioxide and polyoxometalate/$TiO_2$ cocatalysts. Intermediates and mechanistic study, Environ. Sci. Teshnol., 38, p.329-337.
  8. C. Wu, Y. Wue, X. Deng, W. Hua and Z. Gao, 2004, Investigation on the synergetic effect between anatase and rutile nanoparticles in gas-phase photocatalytic oxidations, Catal. Today, 93-95, p.863-869. https://doi.org/10.1016/j.cattod.2004.06.087
  9. A. Sclafani, and J. M. Herrmann, 1996, Comparison of the Photoelectronic and Photocatalytic Activities of Various Anatase and Rutile Forms of Titania in Pure Liquid Organic Phases and in Aqueous Solutions, J. Phys. Chem., 100, p.13655-13661. https://doi.org/10.1021/jp9533584
  10. Q. Samir, T. Malica, A. Ali, 2005, Photocatalytic degradation and adsorption of 2-naphthol on suspended $TiO_2$ surface in a dynamic reactor, J. Colloid and Interface Sci.
  11. C. D. Jean, A. S. Ghassan, P. Plerre, 1990, Photodegradation of 2- and 3-chlorophenol in $TiO_2$ aqueous suspensions Environ. Sci. Teshnol., 24, p.990-996 https://doi.org/10.1021/es00077a007
  12. O. J., Jung, H. I., Choi, K. H., Cheong, 2001, Degradation of some chlorophenols by coated-$TiO_2$ photoreactor, Environ. Eng. Res., 7, p.1-9 https://doi.org/10.4491/eer.2002.7.1.001
  13. C. Tang and V. Chen, 2004, The photocatalytic degradation of reactive black 5 using $TiO_2$/UV in an annular photoreactor Water Reas., 38, p. 2775-2781 https://doi.org/10.1016/j.watres.2004.03.020
  14. B.J.P.A Cornish et al., 2000, Appli. Catal. B: Environ. 25, p.59-67 https://doi.org/10.1016/S0926-3373(99)00121-6
  15. K. hofstadler, R. Bauer, S. Novalic, G. Helsler, 1994, New reactor design for photocatalytic waste water treatment with $TiO_2$ immobilized on fused silica glass fibers: Photomineralization of 4-chlorophenol Environ. Sci. Teshnol., 28, p. 670-674. https://doi.org/10.1021/es00053a021
  16. S. Sakthivel, M. V. Shankar, M. palanichamy, B. Arabindoo, D.W. Bahnemann, V. Murugesan, 2004, Enhancement of photocatalytic activity by metal deposition: characterization and photonic efficiency of Pt, Au and Pd deposited on $TiO_2$ catalyst Water Reas., 38, p. 3001-3008 https://doi.org/10.1016/j.watres.2004.04.046
  17. Y. Li, B. Xu, Y. Fan, N. Feng, A. Qiu, J. M. J. He, H. Yang, Y. Chen, 2004, The effect of titania polymorph on the strong metal-sport interaction of Pd/$TiO_2$ catalysts and their application in the liquid phase selective hydrogenation of long chain alkadienes J. Mole. Catal. A, 216, p.107-114 https://doi.org/10.1016/j.molcata.2004.02.007
  18. I. K. Kim, H. J. Ha, S. K. Lee, J. K. Lee, 2005, Degradation of Chlorophenol by Photocatalysts with Various Transiton Metals, Korean J. Chem. Eng., 22, p.382-386. https://doi.org/10.1007/BF02719415
  19. I. K. Kim, S. J. Yoa, J. K. Lee, C. P. Huang, 2003, Reaction Pathway and Kinetic Modeling for Sonochemical Decomposition of Benzothiophene, Korean J. Chem. Eng., 20, p.1045-1053. https://doi.org/10.1007/BF02706935
  20. J. T. Andersson, S. Bobinger, 1992, Polycyclic aromatic sulfur heterocycles. II. Photochemical oxidation of benzo [b] thiophene in aqueous solution Chemosphere, 24, p.383 https://doi.org/10.1016/0045-6535(92)90412-K
  21. S. Bobinger, J. T. Andersson, 1998, Degradation of the petroleum components monomethylbenzothiophenes on exposure to light Chemosphere, 36(12), p.2569. https://doi.org/10.1016/S0045-6535(97)10219-3