The process of ozonation is optimized when the gaseous ozone is efficiently dissolved into the liquid to be treated. The characteristics of microbubbles, such as high specific interfacial area, slow rising velocity and high inner pressure, suggest their desirability for the mass transfer of gas. In this study, a new microbubble generation system was developed and applied to an ozone contactor, and its characteristics were investigated in a semi-batch bubble column at different gas and water flow rates. The volumetric mass transfer coefficient increases with the increase of both induced-gas and water flow rates. High ozone transfer efficiency was obtained at low gas flow rates, which indicates that the present gas-induced ozone contactor using microbubbles is a desirable device for the dissolution of ozone at high concentrations.
2006 The Society of Chemical Engineers, Japan