Degradation of Triclosan by the Photolysis, the Fenton, and the Hybrid Reaction with Fe$^{2+}$ and UV : A Comparative Study

광반응, 펜톤, 그리고 Fe$^{2+}$와 UV의 조합반응을 이용한 Triclosan의 분해 : 공정 비교 연구

  • Son, Hyun-Seok (Department of Environmental Health, School of Public Health, Seoul National University) ;
  • Zoh, Kyung-Duk (Department of Environmental Health, School of Public Health, Seoul National University)
  • 손현석 (서울대학교 보건대학원 환경보건학과) ;
  • 조경덕 (서울대학교 보건대학원 환경보건학과)
  • Published : 2008.05.31

Abstract

The degradation mechanism of Triclosan(TCS), which is a potent broad-spectrum antimicrobial agent and has been considered as an emerging pollutant, was investigated in the Fenton and the hybrid reaction with Fe$^{2+}$ and UV-C. The results show that the Fe$^{2+}$ is oxidized to 30% by $H_2O_2$, 28% by UV-C, and 15% by UV-A for 10 min. The degradation rate of TCS for beginning time(10 min) was higher in UV-C only reaction than that in hybrid reaction, which of the order was inverted according to the lapse of reaction time. The effect of methanol was the greatest in Fenton reaction, in which the degradation rate of TCS decreased from 90% to 5% by the addition of methanol. Chloride, ionic intermediate, was produced to 77% for 150 min of hybrid reaction(Fe$^{2+}$ + UV-C), which was the greatest. In case with methanol, the generation rate of chloride for 15 min was ignorable in all reactions($\leq$2%) but the hybrid reaction with Fe$^{2+}$ and UV-C(12%). Additionally, the removal rate of TOC in each reaction was estimated as the followed orders; Fe$^{2+}$ + UV-C > Fe$^{2+}$ + $H_2O_2$ > Fe$^{2+}$ + UV-A > UV-C > UV-A. However, the Fenton reaction was almost stopped after 90 min because the reaction between Fe$^{2+}$ and $H_2O_2$ cannot be kept on without adding the oxidant. The phenomena was not observed in the hybrid reaction. In view of generating chloride, the reductive degradation of TCS may be in the hybrid reaction with Fe$^{2+}$ and UV-C, which is favorable to mineralize halogenated organic compounds such as TCS. Consequently, the hybrid process with Fe$^{2+}$ and UV-C may be considered as the alternative treatment method for TCS.

본 연구에서는 펜톤반응, 광반응, 그리고 Fe$^{2+}$와 UV의 조합반응을 이용하여 항균제이면서 신종오염물질 중의 하나인 Triclosan (TCS)에 대한 분해 메커니즘을 해석하였다. 결과에 의하면 Fe$^{2+}$의 산화율은 $H_2O_2$와 UV-C에서 각각 30%와 28%로 차이를 보이지 않은 반면 UV-A의 경우 15%로 차이를 보였다. TCS의 초기 분해속도는 광반응(UV-C > UV-A)이 Fe$^{2+}$와 UV 조합반응과 펜톤 반응보다 높았으나 반응시간의 경과와 함께 Fe$^{2+}$가 포함된 조합반응에서의 분해속도 증가가 관찰되었다. 또한 반응중 메탄올의 첨가에 의해 모든 반응에서 영향을 받았고 펜톤반응의 경우 20분 동안 분해효율 90%에서 5%로 급감되었다. 이온성 부산물인 Cl$^-$의 생성율은 Fe$^{2+}$와 UV-C 조합반응에서 가장 높았으며(77% / 150 min) 메탄올이 첨가된 반응 초기에서는(15 min) 12%의 Cl$^-$ 생성을 보인반면 다른 반응들은 무시할 수준($\leq$2%)이었다. TOC의 제거 역시 Fe$^{2+}$와 UV-C의 조합반응에서 가장 높았으며 펜톤반응, Fe$^{2+}$와 UV-A 조합반응, UV-C 광반응, 그리고 UV-A의 광반응 순으로 낮았다. 그러나 펜톤반응의 경우 90분 후 부터는 반응이 거의 중지되는 것이 관찰되었는데 이는 $H_2O_2$에 의한 Fe$^{2+}$의 산화반응이 중지되었기 때문이다. 이에 반해 Fe$^{2+}$와 UV의 조합공정에서 반응은 지속되었다. 또한 초기 Cl$^-$ 생성은 Fe$^{2+}$와 UV-C의 조합반응에서 환원반응에 의한 TCS의 분해메커니즘을 가지고 있다고 할 수 있다. 환원에 의한 분해는 할로겐화유기화합물의 무기화에 매우 유리하므로 TCS의 대안적 처리방법으로 UV-C와 Fe$^{2+}$의 조합반응은 적용가능하다.

Keywords

References

  1. McMurry, L. M., Oethinger, M., and Levy, S. B., "TCS targets lipid synthesis," Nature, 394, 531-532(1998) https://doi.org/10.1038/28970
  2. Sivaraman, S., Zwahlen, J., Bell, A. F., Hedstrom, L., and Tonge, P. J. A., "Structure-Activity Studies of the Inhibition of FabI, the Enoyl Reductase from Eschrichia coli, by Triclosan: Kinetic Analysis of Mutant FabIs," Biochemistry, 42, 4406-4413(2003) https://doi.org/10.1021/bi0300229
  3. Rule, K. L., Ebbett, V. R., and Vikesland, P. J., "Formation of chloroform and chlorinated organics by freechlorine- mediated oxidation of triclosan," Environ. Sci. Technol., 39(9), 3176-85(2005) https://doi.org/10.1021/es048943+
  4. Morrall, D., McAvoy, D., Schatowitz, B., Inauen, J., Jacob, M., Hauk, A., and Eckhoff, W., "A field study of triclosan loss in river(Cibolo Creek, TX)," Chemosphere, 54, 653-660(2004) https://doi.org/10.1016/j.chemosphere.2003.08.002
  5. Kolpin, D. W., Furlong, E. T., Meyer, M. T., Thurman, E. M., Zaugg, S. D., Barber, L. B., and Buxton, H. T., "Pharmaceuticals, Hormones, and Other Prganic Wastewater Contaminants in U.S. Streams, 1999-2000: A Natioal Reconnaissance," Environ. Sci. Technol., 36, 1202-1211 (2002) https://doi.org/10.1021/es011055j
  6. Singer, H., Muller, S., Tixier, C., and Pillonel, L., "Triclosan: Occurrence and Fate of a Widely Used Biocide in the Aquatic Environment: Field Measurements in Wastewater treatment plants, Surface Waters, and Lake Sediments," Environ. Sci. Technol., 36, 4998-5004 (2002) https://doi.org/10.1021/es025750i
  7. Pemberton, R. M. and Hart, J. P., "Electrochemical behaviour of triclosan at a screen-printed carbon electrode and its voltammetric determination in toothpaste and mouthrinse products," Anal. Chim. Acta, 390, 107-115(1999) https://doi.org/10.1016/S0003-2670(99)00194-4
  8. Tixier, C., Singer, H. P., Canonica, S., and Muller, S. R., "Phototransformation of Triclosan in Surface Waters: A Relevant Elimination Process for This Widely Used Biocide-laboratory Studies, Field Measurements, and Modeling," Environ. Sci. Technol., 36, 3482-3489(2002) https://doi.org/10.1021/es025647t
  9. Mezcua, M., Gomez, M. J., Ferrer, I., Aguera, A., Hernando, M. D., and Ferandez-Alba, A. R., "Evidencce of 2,7/2,8-dibenzodichloro-p-dioxin as a photodegradation in water and wastewater samples," Anal. Chim. Acta, 525, 241-247(2004)
  10. Latch, D. E., Packer, J. L., Arnold, W. A., and McNeill, K., "Photochemical conversion of triclosan to 2,8-dichlorodibenzo- p-dioxin in aqueous solution," J. Photochem. Photobiol. A : Chemistry, 158, 63-66(2003) https://doi.org/10.1016/S1010-6030(03)00103-5
  11. Son, H. S., Choi, S. B., Zoh, K. D., and Khan, E., "Effects of ultravilet intensity and wavelength on the photolysis of triclosan," Water Sci. Technol., 55(1-2), 209-216(2007)
  12. Pignatello, J. J., "Dark and photoassisted $Fe^{3+}-catalyzed$ degradation of chlorophenoxy herbicides by hydrogen peroxide," Environ. Sci. Technol., 26(5), 944-951(1992) https://doi.org/10.1021/es00029a012
  13. 손현석, 김문경, 조경덕, "UV와 $Fe^{2+}$, 그리고 $H_2O_2$를 조합한 고급산화 공정에서의 Pentachlorophenol의 분해속도 연구," 대한환경공학회지, 29(7), 846-851(2007)
  14. Kiwi, J., Pulgarin, C., Peringer, P., and Gratzel, M., "Beneficial effect of homogeneous photo-Fenton pretreatment upon the biodegradation of anthraquinone sulfonate in wastewater treatment," Appl. Catal. B: Environ., 3, 85-91(1993) https://doi.org/10.1016/0926-3373(93)80070-T
  15. Legrini, O., Oliveros, E., and Braun, A. M., "Photochemical processor water treatment," Chem. Rev., 93, 671-698(1993) https://doi.org/10.1021/cr00018a003
  16. Da Silva, J. P., Vieira Ferreira, L. F., Machado, I. F., and Da Silva, A. M., "Photolysis of 4-chloroanisole in the presence of oxygen formation of the 4-methoxyphenylperocyl radical," J. photochem. photobiol. A: Chem., 182, 88-92(2006) https://doi.org/10.1016/j.jphotochem.2006.01.019
  17. Jortner, J. and Stein, G., "The photochemical evolution of hydrogen from aqueous solutions of ferrous ions. PART 1. The reaction mechanism at low pH," J. Phys. Chem., 66, 1258-1263(1962) https://doi.org/10.1021/j100813a012
  18. Josepj, J. M., Vargjese, R., and Aravindakumar, C. T., "Photoproduction of hydroxyl radicals from Fe(III)-hydroxyl complex: a quantitative assessment," J. photochem. photobiol. A: Chem., 146, 67-73(2001) https://doi.org/10.1016/S1010-6030(01)00589-5
  19. Wang, C. Y., Rabani, J., Bahnemann, D. W., and Dohrmann, J. K., "Photonic efficiency and quantum yield of formaldehyde formation from methanol in the presence of various $TiO_2$ photocatalysts," J. Photochem. Photobiol. A: Chemistry, 148, 169-176(2002) https://doi.org/10.1016/S1010-6030(02)00087-4
  20. Feng, J.N.V.K. Aki, S., Chateauneuf, J. E., and Brennecke, J. F., "Abstraction of Hydrogen from Methanol by Hydroxyl Radical in Subcritical and Supercritical water," J. Phys. Chem. A, 107, 11043-11048(2003) https://doi.org/10.1021/jp036179s
  21. Goi, A. and Trapido, M., "Hydrogen peroxide photolysis, Fenton reagent and photo-Fenton for the degradation of nitrophenols: a comparative study," Chemosphere, 46, 913-922(2002) https://doi.org/10.1016/S0045-6535(01)00203-X
  22. Wayne, C. E., and Wayne, R. P., "Photochemistry," Oxford University Press Inc., New York, USA., pp. 1-17, 29-39(2002)
  23. Schwarzenbach, R. P., Gschwend, P. M., and Imboden, D. M., "Environmental organic chemistry," JOHN WILEY & SONS, New York, USA, pp. 436-484(1993)
  24. Rush, J. D. and Bielski, B. H., "Pulse radiloytic studies of the reactions of $HO_2/O_2$- with Fe(II)/Fe(III) ions. The reactivity of $HO_2/O_2$ - with ferric ions and its implication on the occurrence of the Haber-Weiss reaction," J. Phys. Chem., 89, 5062-5066(1985) https://doi.org/10.1021/j100269a035
  25. Song, W., Ma, W., Ma, J., Chen, C., Zhao, J., Huang, Y., and Xu, Y., "Photochemical oscillation of Fe(II)/ Fe(III) ratio induced by periodic flux of dissolved organic matter," Environ. Sci. Technol., 39, 3121-3127(2005) https://doi.org/10.1021/es0483701