Enhanced generation of active oxygen species induced by O3 fine bubble injection under H2O2 addition and UV irradiation

Development of an efficient conversion technique of O-3 to active oxygen species (OS) with high oxidation potential under weakly acidic conditions is described herein. This technique involves the generation of HO2 (-) as an initiator of the radical chain reaction by the addition of H2O2 or/and UV irradiation into aqueous solution during O-3 fine bubble injection. Minimizing the O-3 bubble diameter led to the enhanced production of OS because of the generation of HO2 (-) with contact between O-3 and OH- around the minute gas-liquid interfaces and the promoted reaction of O-3 with HO2 (-) caused by the acceleration of O-3 dissolution in the O-3/H2O2 or O-3/UV systems. Additionally, the generation rate of OS (r (OS)) in the O-3/H2O2/UV system was found to be greater than the summed value of r (OS) in the O-3/H2O2 and O-3/UV systems because of the direct conversion from H2O2 to OH center dot under UV irradiation.