Use of microwave discharge electrodeless lamps (MDEL) : II. Photodegradation of acetaldehyde over TiO2 pellets

A microwave discharge electrodeless lamp (MDEL) filled with low pressure mercury gas has been developed for the photocatalytic treatment of organic air pollutants over anatase TiO2 pellets. The benefit of the combination of MDEL and TiO2 pellets under microwave radiation was assessed by examining the degradation of acetaldehyde in humidified synthetic air. The effect of microwave irradiation was quantified by the decomposition rate of acetaldehyde and the desorption rate of acetaldehyde on the TiO2 surface. It is shown that acetaldehyde is readily transformed at the surface of the TiO2 pellets by the combined action of UV light and microwave irradiation coupling homogeneous and heterogeneous photoreactions.