Heterogeneous Facilitated Transport Membrane via Ionic Liquid‐Mediated Interfacial Polymerization for CO2 Separation

Abstract Polyamide (PA) membranes, prepared by facile and scalable interfacial polymerization (IP), have the potential to serve as candidates for large‐scale CO 2 capture from flue gases in power plants. However, current PA‐based membranes exhibited poor CO 2 separation performance, restricting their large‐scale uses. Herein an ionic liquid (IL)‐mediated IP process is developed for fabricating novel PA‐based heterogeneous facilitated transport membranes (HFTMs) for efficient CO 2 capture. During the IP process, IL regulated and modified the gas transport channels within the PA matrix to accommodate the mobile CO 2 carrier, namely IL itself. Owing to the negatively charged PA matrix and facilitated transport feature, PA/IL (PAIL) membranes exhibited superior and stable CO 2 permeance up to 1 050 GPU and CO 2 /N 2 selectivity up to 300 under simulated flue gas separation conditions. The selectivity of these PAIL membranes is one order of magnitude higher than reported membranes with similar CO 2 permeance and capable of enriching CO 2 from 15% to 97% in one step. Given the one‐step, facile membrane preparation via IP technology, this work may open a new field of synthesizing ultrathin, highly selective HFTMs in a practical and scalable way for highly efficient gas separation applications.