Photocatalytic degradation of several VOCs (n-hexane, n-butyl acetate and toluene) on TiO2 layer in a closed-loop reactor

This paper deals with photocatalytic degradation of three VOCs differing in chemical structure (n-hexane, n-butyl acetate and toluene) in a closed-loop reactor. Degradation tests were performed on particulate layers prepared from TiO2 VLP7000 (Kronos). Concentration dependencies of VOCs were simulated and initial degradation rates calculated. Dependence of the latter on initial concentrations confirms single-site Langmuir-Hinshelwood kinetics with value of hexane adsorption constant 0.023 m(3) mmol(-1). It was shown that butyl acetate is oxidized preferably to hexane when they react in a mixture, while their individual degradation seems to be kinetically similar. Toluene deactivates the photocatalyst and its degradation is thus very slow but the catalyst can be renewed by thermal treatment. The found selectivity or inhibitive ability of investigated VOCs in mixture is important for the proper choice of a suitable purification method of industrial exhaust fumes. (C) 2012 Elsevier B.V. All rights reserved.