A research team has identified a crucial factor related to the chemical activity of acoustic microbubbles and noted a link between the temperature of a liquid and the temperature of the microbubbles produced.
Active bubbles have various applications, including water purification and medical uses. Researchers create microbubbles by exposing liquids to strong ultrasonic waves—a process known as sonication—which heats and compresses the bubbles. For instance, when ultrasonic waves cause bubbles in water to collapse quickly, the temperature inside the bubbles can soar to several thousand degrees, with pressure reaching hundreds of atmospheres.
These bubbles are referred to as active or acoustic bubbles. A research team from Osaka Metropolitan University has identified key indicators to evaluate the chemical activity and temperature of these microbubbles.
The study, led by Professor Kenji Okitsu from the Graduate School of Sustainable System Sciences, revealed that during the sonication of water, the hydrogen production is a more significant measure of acoustic bubbles’ chemical activity than hydrogen peroxide formed during the thermal breakdown of the water.
The researchers also performed experiments with an aqueous t-butanol (a type of tertiary alcohol) solution to study the temperature and quantity of active bubbles produced when subjected to ultrasonic waves. They found that as the solution’s temperature and the concentration of inorganic salts increased, the temperature of the active bubbles decreased, along with a reduction in the number of bubbles generated.
“Our research sheds light on the connections between bubble temperature and chemical activity,” exclaimed Professor Okitsu. “With a better understanding of the properties of active bubbles, we can achieve more precise control over chemical reactions. We anticipate advancements in water purification methods and nanotechnology, including the breakdown of persistent organic pollutants and the creation of valuable, high-performance nanomaterials.”
The results of this study were published in Ultrasonics Sonochemistry.
