A Design Approach to $CrO_x/TiO_2$-based Catalysts for Gas-phase TCE Oxidation

기상 TCE 제거반응용 $CrO_x/TiO_2$계 복합 산화물 촉매 디자인

  • Yang, Won-Ho (Department of Environmental Engineering, Daegu University) ;
  • Kim, Moon-Hyeon (Department of Occupational Health, Catholic University of Daegu)
  • 양원호 (대구대학교 환경공학과) ;
  • 김문현 (대구가톨릭대학교 산업보건학과)
  • Published : 2006.04.30


Single and complex metal oxide catalysts supported onto a commercial DT51D $TiO_2$ have been investigated for gas-phase TCE oxidation in a continuous flow type fixed-bed reaction system to develop a better design approach to catalysts for this reaction. Among the $TiO_2$-supported single metal oxides used, i.e., $CrO_x,\;FeO_x,\;MnO_x,\;LaO_x,\;CoO_x,\;NiO_x,\;CeO_x\;and\;CuO_x$, with the respective metal contents of 5 wt.%, the $CrO_x/TiO_2$ catalyst was shown to be most active for the oxidative TCE decomposition, depending significantly on amounts of $CrO_x\;on\;TiO_2$. The use of high $CrO_x$ loadings greater than 10 wt.% caused lower activity in the catalytic TCE oxidation, which is probably due to production of $Cr_2O_3$ crystallites on the surface of $TiO_2$. $CrO_x/TiO_2$-supported $CrO_x$-based bimetallic oxide catalysts were of particular interest in removal efficiency for this TCE oxidation reaction at reaction temperatures above $200^{\circ}C$, compared to that obtained with $CrO_x$-free complex metal oxides and a 10 wt.% $CrO_x/TiO_2$ catalyst. Catalytic activity of 5 wt.% $CrO_x-5$ wt.% $LaO_x$ in the removal reaction was similar to or slightly higher than that acquired for the $CrO_x$-only catalyst. Similar observation was revealed for 5 wt.% $CrO_x$-based bimetallic oxides consisting of either 5 wt.% $MnO_x,\;CoO_x,\;NiO_x\;or\;FeO_x$. These results represent that such $CrO_x$-based bimetallic systems for the catalytic TCE oxidation on significantly minimize the usage of $CrO_x$ that is well known to be one of very toxic heavy metals, and offer a very useful technique to design new type catalysts for reducing chlorinated volatile organic substances.

순수한 아나타제 구조로 이루어진 DT51D $TiO_2$$CrO_x,\;FeO_x,\;MnO_x,\;LaO_x,\;CoO_x,\;NiO_x,\;CeO_x,\;CuO_x$와 같은 단일 산화물 촉매를 각각 5 wt.% 담지하여 모델반응으로 선택한 기상 TCE 제거반응을 수행하였으며, 이로부터 얻어진 결과를 바탕으로 $CrO_x/TiO_2$-based 복합 산화물 촉매상에서 TCE 산화반응을 연구함으로써 유해 중금속의 사용량을 최소화하기 위한 최적의 촉매 디자인 방법을 도출하고자 하였다. DT51D $TiO_2$에 담지된 여러 단일 금속 산화물들 중에서 기상 TCE 제거반응에 대하여 $CrO_x$가 가장 우수한 촉매활성을 보이는 것으로 나타났으며, 반응온도의 함수로 얻어진 TCE 제거반응의 활성은 $CrO_x$의 담지량에 의존하였다. 5 wt.% $CrO_x$-based 복합 산화물 촉매는 10 wt.% $CrO_x$만으로 이루어진 단일 산화물 촉매와 거의 동일한 수준의 TCE 제거반응 활성을 보였을 뿐만 아니라 이 복합 산화물 촉매들은 10 wt.% $CoO_x,\;MnO_x,\;FeO_x,\;NiO_x$ 등과 같은 단일 산화물 촉매들보다 높은 반응활성을 갖는 것으로 나타났다. 단일 산화물 촉매의 반응활성과 비교하였을 때 5 wt.% $CrO_x$-based 복합 산화물 촉매상에서 TCE 제거반응 동안에 얻어지는 반응활성의 증가 정도는 $420^{\circ}C$ 이하의 반응온도 기준으로 약 $10{\sim}80%$ 이상이었다. 따라서, CVOCs 제거반응을 위하여 널리 사용되고 있는 단일 $CrO_x/Al_2O_3$ 촉매보다는 $CrO_x$의 사용량을 최소화하면서도 우수한 반응활성을 얻을 수 있는 $CrO_x/TiO_2$-based복합 산화물 촉매가 보다 바람직하며 하나의 대안적인 촉매 디자인 방법으로 응용될 수 있을 것으로 생각된다.



  1. Chadha, N. and Parmele, C. S., 'Minimize emissions of air toxics via process change,' Chem. Eng. Prog., 89, 37-42(1993)
  2. Kosusko, M. and Nunez, C. M., 'Destruction of volatile organic compounds using catalytic oxidation,' J. Air Waste Manage. Assoc., 40, 254-259(1990) https://doi.org/10.1080/10473289.1990.10466682
  3. Moretti, E. C., Practical solutions for reducing volatile organic compounds and hazardous air pollutants, Center for Waste Reduction Technologies(CWRT) of the American Institute of Chemical Engineers, New York(2001)
  4. Moretti, E. C. and Mukhopadhyay, N., 'VOC control: Current practices and future trends,' Chem. Eng. Prog., 89, 20-26(1993)
  5. Ruddy, E. N. and Carroll, L. A., 'Select the best VOC control strategy,' Chem. Eng Prog., 89, 28-35(1993)
  6. Bond, G. C. and Sadeghi, N., 'Catalysed destruction of chlorinated hydrocarbons,' J. Appl. Chem. Biotech., 25, 241-248(1975)
  7. Windawi, H. and Wyatt, M., 'Catalytic destruction of halogenated volatile organic compounds,' Platinum Metals Rev., 37, 186-193(1993)
  8. Manning, M. P., 'Fluid bed catalytic oxidation: An underdeveloped hazardous waste disposal technology,' Hazard Waste, 1, 41-65(1984) https://doi.org/10.1089/hzw.1984.1.41
  9. Weldon, J. and Senkan, S. M., 'Catalytic combustion of $CH_3Cl$ by $Cr_2O_3$,' Combust. Sci. Technol., 47, 229-237 (1986) https://doi.org/10.1080/00102208608923875
  10. Wang, Y., Shaw, H., and Farrauto, R. J., 'Catalytic oxidation of trace concentrations of trichloroethylene over 1.5% platinum on ?-alumina,' ACS Symp. Ser., 495, 125 -140(1992)
  11. Scharf, U., Schneider, H., Baiker, A., and Wokaun, A., 'Chromia supported on titania: III. Structure and spectroscopic properties,' J. Catal., 145, 464-478(1994) https://doi.org/10.1006/jcat.1994.1057
  12. Agarwal, S. K., Spivey, J. J., and Butt, J. B., 'Deep oxidation of hydrocarbons,' Appl. Catal. A, 81, 239-255(1992) https://doi.org/10.1016/0926-860X(92)80096-U
  13. Petrosius, S. C., Drago, R. S., Young, V., and Grunewald, G. C., 'Low-temperature decomposition of some halogenated hydrocarbons using metal oxide/porous carbon catalysts,' J. Am. Chem. Soc., 115, 6131-6137(1993) https://doi.org/10.1021/ja00067a031
  14. Yim, S. D., Koh, D. J., Nam, I. S., and Kim, Y. G., 'Effect of the catalyst supports on the removal of perchloroethylene(PCE) over chromium oxide catalysts,' Catal. Lett., 64, 201-207(2000) https://doi.org/10.1023/A:1019076112539
  15. Yim, S. D., Chang, K. H., Koh, D. J., Nam, I. S., and Kim, Y. G., 'Catalytic removal of perchloroethylene(PCE) over supported chromium oxide catalysts,' Catal. Today, 63, 215-222(2000) https://doi.org/10.1016/S0920-5861(00)00462-4
  16. Lindberg, R. C., Reedy, J. D., and Yang, K., 'Decomposition of halogenated organic compounds,' U.S. Patent 4,059,683(1977)
  17. Spivey, J. J. and Butt, J. B., 'Literature review: Deactivation of catalysts in the oxidation of volatile organic compounds,' Catal. Today, 11, 465-500(1992) https://doi.org/10.1016/0920-5861(92)80039-P
  18. Agarwal, S. K., Spivey, J. J., Howe, G. B., Butt, J. B., and Marchand, E., 'Deactivation of chrornia-alumina catalyst for VOC oxidation,' Stud Surf. Sci. Catal., 68, 475 -478(1991) https://doi.org/10.1016/S0167-2991(08)62671-3
  19. Kim, M. H. and Choo, K. H., 'Use of complex metal oxides for catalytic TCEoxidation,' Theor. Appl. Chem. Eng., 9, 1180-1183(2003)
  20. Kim, M. H. and Choo, K. H., 'On-stream activity and surface chemical structure of $CoO_x/TiO_2 $ catalysts for continuous wet TCE oxidation,' J. Environ. Sci., 14, 221-230(2005) https://doi.org/10.5322/JES.2005.14.2.221
  21. Spivey, J. J., 'Complete catalytic oxidation of volatile organics,' Ind. Eng. Chem. Res., 26, 2165-2180(1987) https://doi.org/10.1021/ie00071a001
  22. Royer, S., Duprez, D., and Kaliaguine, S., 'Role of bulk and grain boundary oxygen mobility in the catalytic oxidation activity of $LaCo_{1-x}Fe_xO_3$,' J. Catal., 234, 364-375(2005) https://doi.org/10.1016/j.jcat.2004.11.041
  23. Jagannathan, K., Srinivasan, A., and Rao, C. N. R., 'An XPS study of the surface oxidation states of metals in some oxide catalysts,' J. Catal., 69, 418-427(198l) https://doi.org/10.1016/0021-9517(81)90177-9
  24. Gaspar, A. B., Perez, C. A. C., and Dieguez, L. C., 'Characterization of $Cr/SiO_2$ catalysts and ethylene polymerization by XPS,' Appl. Sur. Sci., 252, 939-949(2005) https://doi.org/10.1016/j.apsusc.2005.01.031