Thermal evaporation of ethanol from an ethanol/water mixture using a hot-bubble evaporator

A method for preferential ethanol removal in dilute solution using a bubble column evaporation process, comprising the steps of passing gas bubbles continuously through an aqueous ethanol solution, extracting ethanol into the vapour phase and collecting it in the rising gas bubbles. It was found that ethanol is specifically adsorbed at the bubble surface and this aids in its removal, especially at mixtures with low ethanol concentrations, where it was expected that the process would be most inefficient, due to the much lower vapour pressure of ethanol in dilute ethanol mixtures, relative to water. Surprisingly, the advanced evaporation of ethanol is clearly explained by the Gibbs adsorption of ethanol at the bubble surface.