Improvement of the rate of sono-oxidation in the presence of CO2

The effect of adding CO2 to the matrix gas on the rate of sono-oxidation was examined. It is already known that CO2 dissolved in water prevents the sonochemical reaction because of the suppression of cavitation intensity. In this study, however, it was observed that the rate of sono-oxidation of I- ions in water increased with the introduction of a small amount of CO2. As the matrix, Ar, He, O-2, and N-2 were used. The improvement was confirmed for all these gases. In the case of Ar, the rate of sono-oxidations was seven times as large as that without CO2. (C) 2015 The Japan Society of Applied Physics