A Study on Oxidative Decomposition of CFC-113 over TiO2-SiO2 Catalysts Prepared by the Sol-Gel Method

솔-젤법으로 제조된 TiO2-SiO2 촉매상에서 CFC-113의 산화분해반응에 관한 연구

  • Chang, Won-Chul (School of Chemical Engineering & Technology, Yeungnam University) ;
  • Lee, Doo-Hyoung (School of Chemical Engineering & Technology, Yeungnam University) ;
  • Lee, Tae-Jin (School of Chemical Engineering & Technology, Yeungnam University)
  • 장원철 (영남대학교 응용화학공학부) ;
  • 이두형 (영남대학교 응용화학공학부) ;
  • 이태진 (영남대학교 응용화학공학부)
  • Received : 1999.01.11
  • Accepted : 1999.10.18
  • Published : 1999.11.10

Abstract

The global environmental problems have been caused by the release of CFCs. Therefore, methods for safe destruction of recoverd CFCs will be eventually needed. The objective of this study was to develop and test a catalyst operating at a mild condition for the decomposition of CFC-113. In this work, catalytic oxidative decomposition of CFC-113 was carried out over aerosol $TiO_2/SiO_2(ATS)$ catalysts prepared by the sol-gel method. All ATS catalysts(Ti/Si mol ratio=1, 2, 2.33, 4) showed high initial activity. However, the deactivation of ATS catalysts was found that more remarkable due to an attack of fluorine and the destruction of ATS structure(Si-F reaction) from analyses of SEM-EDX, XRD than $TiO_2/SiO_2(ATS)$ catalyst prepared by the precipitation method. ATS catalysts prepared by more acidic prehydrolysis condition were found to have still more activity and longer life-time by increasing of acidity. The activity of ATS catalyst also depend on the content of $TiO_2$. There was reason that the acidity of the ATS catalyst was increased with the increased content of $TiO_2$ from 50 to 80 mol %. Solid superacid catalyst ($ATX/SO_4{^{2-}}$) modified with $H_2SO_4$ solution was prepared for high activity and lower deactivation. The reaction of $ATS/SO_4{^{2-}}$ catalyst also exhibited even higher activity and lower deactivation than the original ATS catalyst. It is suggested that the addition of the sulphate species clearly inhibit the deactivation.

Acknowledgement

Supported by : 영남대학교

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