A05 Degradation and mineralization of VOC gas on ultrasonic mist using AOP techniques

Abstract

Advanced oxidation process (AOP) is very effective technique for degradation and mineralization of organic pollutants. On the other hand, ultrasonic atomization is a very useful technique to produce ultrasonic mist which consists of submicron-scale droplets. Using these techniques, volatile organic compound (VOC) gas was decomposed on the mist surface by OH radicals generated by AOPs, and water-soluble decomposition intermediates were rapidly captured into the mist. As a result, the removal rate of toluene under UV/H₂O₂/mist condition was faster than that under UV/H₂O₂ condition. This result indicated that toluene gas could easily react with OH radicals on the mist surface using ultrasonic atomization because gas-liquid interfaces increased by the mist generation. Furthermore, we tried degradation experiments of toluene gas under conditions with ozone addition. Ozone also reacts with H₂O₂ to generate OH radicals (peroxone reaction) on the mist surface, and toluene gas was effectively decomposed there by OH radicals. Since this reaction process strongly affected the improvement of toluene gas removal and mineralization, it can be a useful air purification technique.