An integrated materials approach to ultrapermeable and ultraselective CO₂ polymer membranes

Only few membranes have arrived at the stage of pilot scale due to good separation properties combined with durability and easiness in manufacturing despite the development of several new polymeric materials for CO₂ capture membranes such as thermally rearranged polymers (TR), polymers with intrinsic microporosity (PIM), hybrid polymer-inorganics systems containing metal-organic frameworks (MOFs), zeolites and nanoparticles. Our approach is based on modifying the membrane surfaces with CO₂ reactive groups leading to ultrathin CO₂ selective surface layer. The membrane integrates this highly selective top layer of surface-grown polyamines into a highly permeable but low selective membrane in a concept called “hybrid-integrated membrane"The uniformity of the surface grafting plays a major role on membranes separation properties and depends on grafting conditions, contact angle, and solvents used. Excellent gas permeation results were obtained with CO₂ permeabilities in excess of 1000 Barrer and CO₂/N2 selectivity up to 150-fold higher than reference unmodified membranes. The results show that our approach represents a novel, easy up-scalable preparation method for membranes with excellent CO₂ separation.
Referances
[1] Marius Sandru, E. M. Sandru, W. F. Ingram, J.Deng, P.M. Stenstad, L. Deng, R.J. Spontak, An integrated materials approach to ultrapermeable and ultraselective CO₂ polymer membranes, Science 376 (6588), 90-94 (2022)
[2] Marius Sandru et al., Composite hollow fiber membranes for CO₂ capture, J. of Membrane. Sci. 346 172-186 (2010),
Acknowledgments

This study was supported by the Research Council of Norway through the POLYMEM project (Grant No. 254791) in the CLIMIT program and UEFSCDI Romania through the CO2Hybrid project (Grant No. 13/2020) and the National Science Foundation through the North Carolina Research Triangle Nanotechnology Network (grant no. ECCS-2025064)