Abstract
Influence of microbubbles on the free radical formation by the ultrasonic cavitation have been investigated using KI method as well as coumarin fluorescence probe methods. It was found that microbubbles enhanced the amount of OH radicals when the 45 kHz ultrasound were irradiated to the solution, on the other hand, the amount of OH radicals was reduced by the introduction of microbubbles when the 28 kHz or 100 kHz ultrasound were irradiated to the solution. Influence of microbubbles on the degradation rate of the organic dyes have been investigated by measuring the absorbance of dyes after the irradiation of ultrasound. Similar to the case of KI method as well as coumarin fluorescence probe methods, degradation rate was enhanced only when the 45 kHz ultrasound was irradiated to the microbubble solution. The pH of the dye solution was changed from pH=3 to 10, but similarly degradation rate was fastest when the 45 kHz ultrasound was irradiated to the dye solution with microbbules.
