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 m3 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.

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► Photocatalytic degradation of model VOCs on TiO2 layer carried out.
► Langmuir–Hinshelwood kinetics for hexane confirmed.
► Butyl acetate is oxidized preferably to hexane when reacting in mixture.
► Adsorbed aromatic intermediates (benzoates) of toluene degradation detected.
► TiO2 photocatalyst deactivated by benzoates can be renewed by thermal treatment.