(353e) Gas Chemisorption Blocks Its Diffusion in the Membrane | AIChE

(353e) Gas Chemisorption Blocks Its Diffusion in the Membrane


Hu, L. - Presenter, University At Buffalo
Tran, T., University At Buffalo
Esmaeili, N., University at Buffalo, The State University of New York
Lin, H., University of Buffalo, State University of New Yor
Membranes offer great potential to handle industrial gas separations in an energy-saving way, and highly permeable and selective membranes are desirable. However, leading polymeric membranes suffer an intrinsic permeability-selectivity trade-off that limits them under a performance upper bound. Here, we report a new rational design that introduces functional groups with strong chemisorption towards specific gas molecule in the membrane, thus detaining its diffusion and achieving high selectivity against it, as demonstrated by polyamine membranes for H2/CO2 separation. Amine groups can strongly absorb CO2 molecules and cause high energy barriers for their desorption, leading to extremely poor CO2 transport through the membrane even at high temperatures up to 90 ℃. As such, the polyamine-based thin-film composite (TFC) membrane exhibits an unprecedented ideal H2/CO2 selectivity of 1100 at 70 ℃, a new record on polymer-based membranes. Moreover, the TFC membrane shows stable and superior H2/CO2 separation performance, far surpassing the upper bound and state-of-the-art membranes, indicating great potential to be scaling-up. This study presents a new direction on designing highly selective membranes for a variety of separations and other applications.