Importance of sonoluminescence and sonochemistry for understanding and optimizing ultrasound applications

Ultrasound has shown to improve a spectrum of applications such as crystallization, degradation, synthesis, extraction, and cell disruption. These improvements largely stem from the cavitation induced extreme physical and/or chemical effects. Cavitation activities are often quantified using sonoluminescence intensity or sonochemical yield and are dependent on sonication conditions. For example, frequencies less than 100 kHz produces stronger physical effects and higher sonoluminescence per bubble, whereas frequencies between 200 and 800 kHz give rise to higher sonochemical yields. Similarly, solution conditions are equally important as 50% air saturation or addition of 1 mM anionic surfactant (sodium dodecyl sulfate) have shown to enhance sonoluminescence intensity. Often frequency and power are varied to assess its impact on a given application. However, this often do not reveal the underlying mechanisms to clearly assess whether the system could be further optimized or better designed to tailor for a particular application. This presentation aims to show the importance of complimentary evaluation of the sonoluminescence and sonochemical yield and also provide case studies on sonocrystallization, degradation of pollutants, and sono-grafting on membranes.