Photocatalytic degradation of gaseous toluene in an ultrasonic mist containing TiO2 particles

Photocatalytic degradation of toluene gas in a mist formed by ultrasonic atomization of slurried TiO2 was studied under various conditions. Upon irradiation at 365 nm, toluene was decomposed and mineralized by photocatalytic reaction on the mist surface or inside it. The toluene removal ratio increased as the amount of TiO2 in the slurry was increased. Under UV254+185 irradiation, the mineralization ratio was higher than at 365 nm. We propose that under UV254+185 irradiation, toluene was immediately converted to water-soluble intermediates by direct photolysis and O3 oxidation in the gas phase and that these intermediates were captured in the mist and photocatalytically mineralized to CO and CO2. This paper indicates a new effective utilization of ultrasonic mist and TiO2 photocatalyst.