염소계 유기화합물 제거를 위해 사용되는 크롬산화물 촉매상에서 반응물 농도에 대한 촉매의 안정성 및 활성저하 mechanism에 대한 연구가 수행되었다. 우수한 제거활성을 지니는 높은 표면적의 CrOx/TiO2 및 CrOx/Al2O3 촉매상에서 반응물인 PCE 농도를 30, 1,000, 5,000, 10,000 ppm으로 증가시켰을 때 30 ppm의 낮은 PCE 농도에서는 두 촉매 모두 100시간 이상의 반응시간동안 활성저하 없이 안정된 제거성능을 보였다. 그러나 1,000 ppm 이상의 고농도 PCE가 공급되었을 경우에는 그 농도에 비례하여 크롬계 촉매의 활성저하 정도가 심화되었다. 촉매의 활성저하는 크롬의 휘발이나 coking에 의한 비표면적의 감소에 기인되었다기보다는 크롬산화물이 고농도의 반응물에 의하여 활성점으로 작용하는 높은 산화수의 Cr(VI)에서 Cr(III)로의 환원에 의한 상전이 때문인 것으로 밝혀졌다. 비록 활성이 저하된 촉매들에서 반응물의 농도와 반응시간에 비례한 소량의 크롬 질량감소가 관찰되었지만 활성저하에 영향을 줄 정도는 아니었다.

The effect of the concentration of reactant on the deactivation of chromium oxide catalysts for the oxidation of CVOCs was investigated. Feeds with various PCE concentrations of 30, 1,000, 5,000 and 10,000 ppm were introduced into the reactor for the oxidation over CrOx catalysts supported on high surface area TiO2 and Al2O3 . Both chromium oxide catalysts exhibited stable PCE removal activities up to 100 hours of reaction time without any catalyst deactivation at the low concentration of PCE in the feed, 30 ppm. However, high concentrations of PCE, from 1,000 to 10,000 ppm, significantly deactivated the chromium oxide catalyst regardless of the support. Deactivation of the chromium oxide catalyst was neither caused by the evaporation of chromium from the catalyst surface nor the reduction of surface area by coking. It was mainly due to the phase transformation from Cr(VI), active reaction sites on the catalyst surface, to Cr(III). Although some of Cr on the catalyst surface evaporated during the course of the reaction at high feed concentrations of PCE, it was insignificant to reduce the PCE removal activity of the catalyst.

Deactivation Perchloroethylene(PCE) Chromium Oxide

Spivey JJ, Ind. Eng. Chem. Res., 26, 2165 (1987) 
Ruddy EN, Carroll LA, Chem. Eng. Prog., 89(7), 28 (1993)
Ramanathan K, Spivey JJ, Combust. Sci. Technol., 63, 247 (1989)
Manning MP, Hazard. Waste, 1, 41 (1984)
Weldon J, Senkan SM, Combust. Sci. Technol., 63, 247 (1989)
Kageyama Y, U.S. Patent, 3,972,979 (1976)
Petrosius SC, Drago RS, Young V, Grunewald GC, J. Am. Chem. Soc., 115, 6131 (1993) 
Storaro L, Ganzerla R, Lenarda M, Zanoni R, Lopez AJ, Pastor PO, Castellon ER, J. Mol. Catal. A-Chem., 115, 329 (1997) 
Chatterjee S, Greene HL, J. Catal., 130, 76 (1991) 
Kawi S, Te M, Catal. Today, 44(1-4), 101 (1998) 
Solymosi F, Rasko J, Papp E, Oszko A, Bansagi T, Appl. Catal. A: Gen., 131(1), 55 (1995) 
Hong CW, Kim MH, Nam IS, Kim YG, HWAHAK KONGHAK, 36(2), 206 (1998)
Yim SD, Koh DJ, Nam IS, Kim YG, Catal. Lett., 64(2-4), 201 (2000)
Spivey JJ, Butt JB, Catal. Today, 11, 465 (1992) 
Agarwal SK, Spivey JJ, Butt JB, Appl. Catal. A: Gen., 82, 259 (1992) 
Chatterjee S, Greene HL, Park YJ, Catal. Today, 11, 569 (1992) 
Rachapudi R, Chintawar PS, Greene HL, J. Catal., 185(1), 58 (1999) 
Padilla AM, Corella J, Toledo JM, Appl. Catal. B: Environ., 22(2), 107 (1999) 
Hagenmaier H, Tichaczek KH, Brunner H, Mittelbach H, Organohalogen Compounds, 3, 65 (1990)
Yim SD, Koh DJ, Nam IS, in Proceeding of ICIPEC, Seoul, 405, June 8-10 (2000)
Imamura S, Catal. Today, 11, 547 (1992) 
Zaki MI, Fouad NE, Bond GC, Tahir SF, Thermochim. Acta, 285(1), 167 (1996) 
Mul G, Kapteijn F, Doornkamp C, Moulijn JA, J. Catal., 179(1), 258 (1998) 
Cordi EM, O'Neill PJ, Falconer JL, Appl. Catal. B: Environ., 14(1-2), 23 (1997) 
Mars P, Van Krevelen DW, Chem. Eng. Sci., 3, 41 (1954)