Photocatalytic oxidation of trichloroethylene in humidified atmosphere

Gas-phase UV-assisted catalytic oxidation of trichloroethylene (TCE) has been studied over TiO2 glass fiber cloth (TiO2-GFC) in a cylindrical batch reactor at different humidity levels. The apparent intermediates and products were determined by Fourier transform infrared (FTIR) spectroscopy. The effect of humidity on the photochemical oxidation reaction of TCE has also been studied in order to further elucidate the inhibitive effect of water vapor during TCE photocatalytic oxidation. After Cl atoms are generated from a possible attack of moisture-derived hydroxyl radicals on TCE, competitive adsorption between TCE and water molecules did not totally account for the reaction inhibition in humidified atmosphere. The suppression of the Cl atom-propagated chain reaction has been postulated as an additional reason for the reaction inhibition. Humidification increased the possibility of dichloroacetyl chloride (DCAC) and phosgene hydrolysis and the yield of CO2 increased monotonically. (C) 2001 Elsevier Science B.V. All rights reserved.