Effect of frequency on sonochemical reactions II. Temperature and intensity effects

The effects of temperature and intensity on the rate of sonochemical oxidation of aqueous potassium iodide with irradiation at two frequencies, 20 and 900 kHz, were investigated. The results show that at 900 kHz the rate of oxidation can increase with temperature, up to 30°C at lower power levels, whereas at 20 kHz, the rate of oxidation decreases with increasing temperature. The rate at 20 kHz depends markedly on the horn tip area. With the same acoustic power, the rate was greater when the area was greater. Extrapolation of these results indicates that the real effect of frequency on the sonochemical oxidation of iodide at 900 kHz is about twice that at 20 kHz under optimum conditions.