抄録
In previous paper, we demonstrated the rate of sono-oxidation of 0.1 M KI increased with the
introduction of a small amount of CO2 and had a peak value. Because H radicals produced from water by
sonication are quenched by CO2 and OH radicals are expected to remain. However, after the maximum value,
absorbance decreased with increasing CO2. As you know, presence of CO2 in the system is to suppress
sonochemical reaction. In this presentation, we discussed rate control factors for sono-oxidation under a
CO2-Ar atmosphere. Ultrasonic irradiation was performed using an ultrasonic atomizer (Honda Electric
HM-303N, 2.4 MHz, 15W)for 10 min at 25°C. Before sonication, the reactor was filled with argon gas and
certain amount of CO2 was injected. The rate of sono-oxidation was evaluated by potassium iodide (0.01 M
KI) dosimetry using UV-Vis spectrophotometer (JASCO V-650, measuring wavelength is 355 nm).
We concluded that effect of reactant volume on the rate of sono-oxidation was clear and the best volume was
10 ml in our system. In that case, the absorbance was 4 times as high as one without CO2. The effect of KI
concentration, however, was not clear. Because of increasing pH value of solution, concentration of CO2 in the
solution might decrease during sonication.
