Research of oxygen mass transfer through the air-water surface at low bulk concentrations of surfactants

Abstract

Oxygen transfer from the gaseous to the liquid phase is often technologically a very energy-consuming process. We studied the influence of small alcohol molecules (1-butanol, 2-butanol, 2-methyl-propanol, and 2-methyl-2-propanol) as surfactants to oxygen permeability and addressed the importance of experimental methodology. The oxygen mass transfer rate in the air-water surface layer was calculated by using an original technique and the results were compared to the surface tension values obtained by the Du Nouy ring method. Our experiments revealed that oxygen permeability was inhibited already at very low surfactant concentrations (0.1-1 mmol/L), whereas a considerable increase in the surface tension was observed in a 1000-fold higher concentration range. These results demonstrate the importance of methodological considerations in the research of surface action of surfactants.