UC Irvine

We describe a theoretical framework for predicting bulk nanobubble size of any given combination of a gas and water, based upon the force balance at the gas/liquid interface. We show how this balance can develop between the internal pressure, external pressure and surface tension, and the electrostatic repulsion of hydroxide ions adhered to the surface of the nanobubble that gives rise to their relatively high negative zeta potential. We also analyse the adsorption of hydroxide ions at the surface of the nanobubble and the dependence of nanobubble formation on pH and the required initial size of a bubble that leads to the formation of a stable nanobubble. Further analysis is carried out on the velocity of the bulk nanobubble due to Brownian motion, and its effects on the rates of diffusion of the gas into the water, as well analysis on the interaction between hydroxide ions and oxygen molecules to infer the inhibition of their diffusion. Future applications and methodologies for applications, based on the equations proposed are also discussed.