Effective and Environment-Friendly Oil Removal with Microbubble Jet*

This study investigates the fundamental physics underlying the use of microbubble jets to enhance oil-cleaning processes, providing an eco-friendly alternative to conventional chemical methods that pose significant environmental and health risks. Microbubbles, particularly those under 50 µm, offer prolonged suspension in water and effective pollutant adsorption, beneficial in surface cleaning applications. Previous research has focused on underwater applications, yet the detailed mechanisms of microbubble-enhanced cleaning remain unclear, especially in diverse fluidic environments.

To address this gap, this research explores the physics of microbubble generation via ultrasonic agitation, examining the effects of water temperature, ultrasonic amplitude, and surfactant concentration on their properties, such as concentration, size distribution, and lifetime. Flow visualization and particle image velocimetry (PIV) revealed key mechanisms of surface cleaning, including oil adsorption by microbubbles and enhanced jet instability and turbulence intensity. Results show a 1.29-fold improvement in cleaning efficiency with microbubble jet, demonstrating a higher velocity decay rate and better spreading across surfaces than single-phase jet, highlighting its potential as a promising, eco-friendly cleaning solution.