Encapsulated Amino Acid-Based Ionic Liquid for CO₂ Separation Membranes

Abstract

Membrane technology has been valuable for the transition to a fully sustainable economy. We demonstrate the application of amino-acid-based ionic liquids integrated into polymeric membranes for the preferential transport of carbon dioxide (CO2). This material has a high absorption capacity for CO2, increasing its solubility in the membrane and, consequently, permeability. The amino-acid-based ionic liquid is encapsulated in porous carbon capsules to avoid leaching out during the membrane operation. The selective layer polymer matrix was constituted by Pebax1657. The addition of 1 wt % of encapsulated amino-acid–base ionic liquid led to a more than 2-fold permeability enhancement while maintaining the ideal selectivity for CO2 over other light gases. The permeability was even higher when tested with humid mixed gases without compromising the selectivity.