2014 年 29 巻 2 号 p. 112-118
Degradation of volatile organic compound (VOC) gas by ultrasonic mist was investigated using a batch reactor under various experimental conditions. The experiments were conducted with or without hydrogen peroxide (H2O2) under 254 nm of UV irradiation. In the techniques with H2O2, VOC gas was removed by adsorption or reaction with OH radicals generated from H2O2 on the mist surface or inside it. Since 100% of toluene gas could be removed under all conditions by the adsorption or reaction with OH radicals on the mist surface, we evaluated the reactivity under the various experimental conditions by their reaction rates. The removal rate of toluene under UV/H2O2/mist condition was faster than that under UV/pure water/mist condition. Therefore, it is evident that H2O2 plays an important role in the generation of OH radicals and removal of gaseous VOC. Furthermore, in cases of 200 kHz of high frequency ultrasonic irradiation for the continuous generation of H2O2, sufficient removal rates were obtained not only under 200 kHz/UV/pure water/mist condition but also under 200 kHz/pure water/mist condition. Therefore, the results indicate that 200 kHz of ultrasound irradiation has a capability of continuous supply of H2O2, and a direct reaction with toluene by creating reactive cavities.
