Photodegradation of benzene, toluene and xylenes under visible light applying N-doped mixed TiO2 and ZnO catalysts

N-doped TiO2/ZnO catalysts were prepared by sol-gel technique and calcined at 380 and 500 degrees C. Its photocatalytic activity was evaluated in the photodegradation of benzene, toluene and xylenes (BTX) under visible-LED light and compared with the undoped TiO2/ZnO activity. The amount of doped nitrogen was found to be 0.64 at%. Concentrations of BTX were analysed by gas chromatography applying the headspace technique. The N-TiO2/ZnO catalyst calcined at 500 degrees C led to reductions of benzene, toluene and xylenes concentrations greater than 80 wt% after 120 min of irradiation. The photocatalytic reactions followed the first order kinetics. (C) 2014 Elsevier B.V. All rights reserved.