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A Self‐Consistent Model for Sorption and Transport in Polyimide‐Derived Carbon Molecular Sieve Gas Separation Membranes
Author(s) -
Sanyal Oishi,
Hays Samuel S.,
León Nicholas E.,
Guta Yoseph A.,
Itta Arun K.,
Lively Ryan P.,
Koros William J.
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202006521
Subject(s) - sorption , membrane , gas separation , molecular sieve , microporous material , polymer , carbon fibers , pervaporation , transport phenomena , chemical engineering , materials science , chemistry , polymer science , thermodynamics , adsorption , organic chemistry , permeation , physics , engineering , composite material , composite number , biochemistry
Demand for energy‐efficient gas separations exists across many industrial processes, and membranes can aid in meeting this demand. Carbon molecular sieve (CMS) membranes show exceptional separation performance and scalable processing attributes attractive for important, similar‐sized gas pairs. Herein, we outline a mathematical and physical framework to understand these attributes. This framework shares features with dual‐mode transport theory for glassy polymers; however, physical connections to CMS model parameters differ from glassy polymer cases. We present evidence in CMS membranes for a large volume fraction of microporous domains characterized by Langmuir sorption in local equilibrium with a minority continuous phase described by Henry's law sorption. Using this framework, expressions are provided to relate measurable parameters for sorption and transport in CMS materials. We also outline a mechanism for formation of these environments and suggest future model refinements.