Ultrasonic irradiation of alkaline oxic aqueous

We recently reported (3) that ultrasonic irradiation of alkaline oxic aqueous solutions of bivalent sulfur, S(-II), at 20 kHz resulted in the rapid oxidation of S(-II). The observed distribution of the oxidation products was similar to that reported for y-radiolysis of S(-II). The ultrasound-induced oxidation of S(-II) in alkaline solutions was attributed to the reaction of HS" with OH radicals (3). These radicals form during ultrasonic irradiation of water as a result of the high-temperature decomposition of water vapor inside the hot cavitation bubbles (1,2). Although the experimental results were qualitatively consistent with our proposed mechanism, some questions remained unanswered concerning the amount of OH released into the aqueous phase and the existence and relative importance of additional oxidants. 

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