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Hyperaging Tuning of a Carbon Molecular‐Sieve Hollow Fiber Membrane with Extraordinary Gas‐Separation Performance and Stability
Author(s) -
Qiu Wulin,
Vaughn Justin,
Liu Gongping,
Xu Liren,
Brayden Mark,
Martinez Marcos,
Fitzgibbons Thomas,
Wenz Graham,
Koros William J.
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201904913
Subject(s) - molecular sieve , membrane , selectivity , gas separation , fiber , polyimide , hydrogen , molecule , chemical engineering , materials science , ethylene , carbon fibers , sieve (category theory) , nanotechnology , chemistry , organic chemistry , composite material , adsorption , catalysis , layer (electronics) , biochemistry , mathematics , combinatorics , engineering , composite number
Abstract This study reports 6FDA:BPDA‐DAM polyimide‐derived hollow fiber carbon molecular‐sieve (CMS) membranes for hydrogen and ethylene separation. Since H 2 /C 2 H 4 selectivity is the lowest among H 2 /(C 1 ‐C 3 ) hydrocarbons, an optimized CMS fiber for this gas pair is useful for removing hydrogen from all‐cracked gas mixtures. A process we term hyperaging provides highly selective CMS fiber membranes by tuning CMS ultramicropores to favor H 2 over larger molecules to give a H 2 /C 2 H 4 selectivity of over 250. Hyperaging conditions and a hyperaging mechanism are discussed in terms of an expedited physical aging process, which is largely controlled by the hyperaging temperature. For the specific CMS material considered here, a hyperaging temperature beyond 90 °C but less than 250 °C works best. Hyperaging also stabilizes CMS materials against physical aging and stabilizes the performance of H 2 separation over extended periods. This work opens a door in the development of CMS materials for the separation of small molecules from large molecules.