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Creation of Well‐Defined “Mid‐Sized” Micropores in Carbon Molecular Sieve Membranes
Author(s) -
Ma Yao,
Jue Melinda L.,
Zhang Fengyi,
Mathias Ronita,
Jang Hye Youn,
Lively Ryan P.
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201903105
Subject(s) - membrane , microporous material , chemical engineering , permeation , pyrolysis , molecular sieve , polymer , materials science , gas separation , triptycene , polymer chemistry , nanotechnology , chemistry , organic chemistry , adsorption , composite material , biochemistry , engineering
Carbon molecular sieve (CMS) membranes are candidates for the separation of organic molecules due to their stability, ability to be scaled at practical form factors, and the avoidance of expensive supports or complex multi‐step fabrication processes. A critical challenge is the creation of “mid‐range” (e.g., 5–9 Å) microstructures that allow for facile permeation of organic solvents and selection between similarly‐sized guest molecules. Here, we create these microstructures via the pyrolysis of a microporous polymer (PIM‐1) under low concentrations of hydrogen gas. The introduction of H 2 inhibits aromatization of the decomposing polymer and ultimately results in the creation of a well‐defined bimodal pore network that exhibits an ultramicropore size of 5.1 Å. The H 2 assisted CMS dense membranes show a dramatic increase in p ‐xylene ideal permeability (≈15 times), with little loss in p ‐xylene/ o ‐xylene selectivity (18.8 vs. 25.0) when compared to PIM‐1 membranes pyrolyzed under a pure argon atmosphere. This approach is successfully extended to hollow fiber membranes operating in organic solvent reverse osmosis mode, highlighting the potential of this approach to be translated from the laboratory to the field.