P17 ウルトラファインバブルの生成・消滅に及ぼす超音波条件の影響

抄録

Bubbles of less than 1 μm in diameter are called ultrafine bubbles (UFB). When ultrasound was irradiated to ultrapure water in a vessel, the change of number density of UFB with irradiation time was investigated in ultrasonic frequency at 22, 43, 129, 488 kHz and 1 MHz. The number density of UFB exponentially increased with irradiation time. The number density of UFB increased with decreasing frequency. The mean and mode diameters of UFB after ultrasonic irradiation for 5 minutes to ultrapure water were 100 - 120 nm and 90 - 100 nm, respectively. Furthermore, when ultrasound was irradiated to water containing high-concentration UFB, the change of number density of UFB with irradiation time was investigated. The number density of UFB decreased exponentially with irradiation time. The number density of UFB decreased with increasing frequency. Therefore, it was clear that generation and reduction of UFB occurred simultaneously by ultrasonic irradiation to water.