New insights into acoustic bubbles give boost to future applications

These bubbles are called active bubbles or acoustic bubbles. Osaka Metropolitan University researchers have now found key indicators to assess the chemical activity and temperature of these microbubbles.

The group led by Professor Kenji Okitsu of the Graduate School of Sustainable System Sciences showed that, when water is undergoing sonication, the amount of hydrogen is a more important indicator of the chemical activity of acoustic bubbles than hydrogen peroxide during thermal decomposition of the water.

The team also conducted experiments using an aqueous t-butanol (tertiary alcohol) solution to investigate the temperature and number of active bubbles generated when exposed to ultrasonic waves. As the temperature of the solution and the concentration of inorganic salts increased, the temperature of the active bubbles became lower and the number of active bubbles produced decreased.

“Our research provides new insights into the relationship between bubble temperature and chemical activity,” Professor Okitsu exclaimed. “As the characteristics of active bubbles become clearer, more precise control of chemical reactions will become possible. We expect further applications and progress in water purification technology and nanotechnology, such as the decomposition of persistent organic pollutants and the synthesis of highly functional, high value-added nanomaterials.”

The findings were published in Ultrasonics Sonochemistry.