The Pursuit of Energy Reduction in Generation of Stable Nanobubbles

Abstract

The repeatable and cost-efficient generation of nanobubbles is still a challenge. In most cases, the hydrodynamic generation of nanobubbles is used at larger scales. Therefore, every cost reduction possible in nanobubble generation is needed. In this work, we decided to check how the generation of nanobubbles changes when the surrounding liquid properties change. The generation of nanobubbles was carried out in a novel setup, designed by us. We investigated the minimum liquid velocity needed for nanobubble generation and propose correlations describing this based on the physicochemical properties of the liquid and gas phases. As carbon dioxide nanobubbles are commonly used for the treatment of ischemia and chronic wounds, the investigation of their stability enhancement is crucial for the wider public. We investigated the minimum rotation rate of the impeller needed for CO2 nanobubble generation and the influence of a biomedical surfactant (Pluronic P-123) addition and concentration change on the size of nanobubbles and their stability over time. Nanobubbles were stable in the presence of surfactant additions and showed the impact of both changes in generation time and shear stress on their size. We hope that this study will be a step in the direction of the cost-efficient generation of stable carbon dioxide nanobubble dispersions.