Author(s)

Daisuke Kobayashi¹, Chiemi Honma², Hideyuki Matsumoto^3,4, Katsuto Otake², Atsushi Shono²

¹Department of Applied Chemistry, Tokyo Denki University, Tokyo, Japan.
²Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, Tokyo, Japan.
³Renewable Energy Research Center, Department of Energy and Environment, Advanced Industrial Science and Technology, Koriyama, Japan.
⁴Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan.

Ultrasound is used in various chemical reaction processes, and these reactions are influenced by ultrasonic frequency. A threshold power is required for the ultrasonic degradation reaction and oxidation reaction caused by hydroxyl radicals, and the cavitation threshold power is also influenced by frequency generally. In this study, the effects of frequency on the threshold power of methylene blue degradation and KI oxidation were investigated in the range between 22.8 kHz and 1640 kHz. The threshold power of KI oxidation reaction increased with increasing frequency. This phenomenon well agrees with previous study, and it is revealed that the generation of I^-₃ ion is caused by oxidation reaction of I^ˉ ions with hydroxyl radicals. On the other hand, the threshold power of methylene blue degradation reaction was not affected by frequency. The ultrasonic degradation of methylene blue is considered to be caused by hydroxyl radicals, and there is a linear relationship between degradation rate constant and sonochemical efficiency value. However, it is guessed that the degradation of methylene blue is occurred inside cavitation bubble by pyrolysis at high frequency regions.

Degradation, Methylene Blue Degradation, KI Oxidation, Frequency, Threshold Power

Kobayashi, D. , Honma, C. , Matsumoto, H. , Otake, K. and Shono, A. (2018) Comparison of Threshold Power between Methylene Blue Degradation and KI Oxidation Reaction Using Ultrasound. Open Journal of Acoustics, 8, 61-69. doi: 10.4236/oja.2018.84006.