Analysis of Laplace–Young equation parameters and their influence on efficient CO2 capture in membrane contactors

• A method to estimate surface tension of aqueous alkanolamine solutions was developed.
• A useful criterion to prevent membrane wetting was proposed.
• The lamination process increases the liquid/membrane contact angle.

Based on wetting-related properties like liquid surface tension, contact angle, membrane breakthrough pressure and chemical stability, this work aims to perform a thorough analysis of these properties on different potential membrane/liquid combinations in order to develop an appropriate way to select the best conditions to elude the unwanted wetting phenomenon in membrane contactors (MC). From new experimental data and a systematic review from literature, several significant results were obtained. First, a new and very simple classification method for the estimation of surface tension of aqueous amine, alcohol or alkanolamine solutions was developed. Second, in addition to polytetrafluoroethylene (PTFE) and polypropylene (PP) (to a lesser extend), laminated PTFE/PP membranes were found to be an interesting alternative to be considered in plate MC because the lamination process leads to higher contact angle values. Finally, a new criterion for long-term performance of gas absorption in MC was proposed. It was estimated that a ratio between the liquid overpressure and the nominal breakthrough pressure less than 1.5% could be a useful criterion to prevent membrane wetting and several actions were suggested to respect it.