Modelling of removal of surfactants from liquid solutions in a bubble column

Abstract

This paper proposes a theoretical model for the separation of a surfactant from water in a bubble column. The proposed model includes both mass balance and adsorption thermodynamics of surfactants on bubble surfaces in the liquid solution (e.i. surface equations of state and adsorption isotherms). This is very important because models, found in the literature, did not consider adsorption thermodynamics. The proposed model successfully predicted the experimental results. It was found that the separation efficacy was higher at a lower surfactant concentration in the liquid than that at a higher surfactant concentration; the reason is probably that available bubble surface areas for adsorption of the surfactant were higher at a lower surfactant concentration. A higher cross-sectional area of the column led to a better separation performance due to a larger amount of generated bubble surfaces. A low gas flow rate and low liquid fraction resulted in the best separation performance.

Keywords

• Surfactant separation
• Bubble column
• Mathematical model
• Surface tension