VOC photodegradation at the gas-solid interface of a TiO2 photocatalyst -: Part I:: 1-butanol and 1-butylamine

The gas-solid heterogeneous photocatalytic oxidation of 1-butanol and 1-butylamine in air was investigated using supported TiO(2) as a catalyst. The supported catalyst was prepared using a sol-gel method and irradiated employing two different light sources, a medium pressure mercury lamp or a xenon-chloride excimer lamp. The experimental set-up was especially designed for generating a gas stream containing stable and defined concentrations of the model pollutants. The gas stream at the reactor exit was analyzed on line by gas chromatography and the structures of the intermediates were established by gas chromatography coupled with mass spectrometry. Six major intermediates (butanal, butanoic acid, 1-propanol, propanal, ethanol and ethanal) were identified in the case of the photocatalytic degradation of 1-butanol. 1-Butylamine was less efficiently adsorbed on the catalyst and its degradation was slower. Three intermediates could be identified in this case (N-butylidene-1-butylamine, N-ethylidene-1-butylamine and N-butylformamide). Based on these results, a degradation mechanism is proposed for both compounds. Mineralization could be achieved under various conditions of concentrations and flow rates and was confirmed by infrared spectroscopy. (C) 2000 Elsevier Science S.A. All rights reserved.