Pergamon Chemosphere, Vol. 35, No. 12, pp. 2881-2889, 1997 0 1997 Elsevier Science Ltd All rights reserved. Printed in Great Britain 0045-6535197 $17.00+0.00 PII: SOO45-6535(97)00364-O THE GAS-PHOTOCATALYTIC DEGRADATION OF TRICHLOROETHYLENE WITHOUT WATER Hong Liu, Shao’an Cheng*, Jianqing Zhang, Chunan Cao, Weichuan Jiang Department of Chemistry. Zhejiang University, Hangzhou, P .R. China (Received in Germany 27 May 1997; accepted 31 July 1997) ABSTRACT ‘The photocatalytic degradation of gaseous trichloroethylene (TCE) without water has been studied. The degradation products were determined to be (‘02. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPON HC’l and (‘12, and the reaction stoichiometr\, h v was described as C2 HCI, + 20, --) HCI + 2C0, + (‘I,. The degradation rate was found to be linear i!O? with 0.16 power of the illumination intensity. When the TC’E concentration was low (IO-’ mol [.I’ or a little more), its degradation rate model could be considered as first order kinetics. A mechanism oi valence band hole oxidation was proposed. 01997 Elsevier Science Ltd KEYWORDS Gas Photocatalysis, Trichloroethylene. Degradation 1) INTRODIJC’TION Organochlorine solvents are zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA used widely in various industries. The contamination of water supplie:. aquatic and atmospheric environments with such chlorinated organic compounds presents a seriou,; environmental problem owing to the toxicity potential and stability of these compounds. TC’E is the most common and typical contaminant of the organochlorine solvents and processes which call destroy this compound are of great interest. Man) of the commonly used treatment technologies for TC’E simply change the phase of the pollutant (such as air-bubbling and adsorption on carbon). (*to whom correspondence should be addressed) 2881