Efficient removal of toluene and benzene in gas phase by the TiO2/Y-zeolite hybrid photocatalyst

Efficient removal of toluene or benzene molecules thinly diffused in gas phase was achieved by using TiO2/Y-zeolite hybrid photocatalysts. TiO2 of 10 wt% hybridized with a hydrophobic USY zeolite showed higher photocatalytic reactivity as compared to TiO2 hybridized with hydrophilic H-Y or Na-Y zeolites. This phenomenon can be explained by the fact that the hydrophobic USY zeolite efficiently adsorbs the organic compounds and smoothly supplies them onto the TiO2 photocatalyst surface. However, the toluene or benzene molecules, which are strongly trapped on the hydrophilic H+ or Na+ sites of zeolite, cannot diffuse onto the TiO2 surfaces, resulting in lower photocatalytic reactivity. Although the adsorption capacity of the pure TiO2 sample rapidly deteriorated, the TiO2/Y-zeolite hybrid system maintained a high adsorption efficiency to remove such aromatic compounds for a long period. (C) 2012 Elsevier B.V. All rights reserved.