Elucidating the role of micropore-generating backbone motifs and amine functionality on H2S, CO2, CH4 and N2 sorption
Name
2024_PAD_pae-nh2-part 1.pdf
Description
Accepted version
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787.42 KB
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c26974a10a6d298adfd7d08f9db95d7c
Name
2024_PAD_pae-nh2-part 1- SI final.pdf
Description
Supporting information
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2.29 MB
Format
Adobe PDF
Checksum (MD5)
13a3c6435d2684c15f0261ec5d04ac83
Author(s)
Dean, Pablo A
Mizrahi Rodriguez, Katherine
Guo, Sheng
Roy, Naksha
Swager, Timothy M
Smith, Zachary P
Date Issued
January 18, 2024
Journal
Journal of Membrane Science
Publisher
Elsevier BV
Version
Author's final manuscript
Abstract
Microporous polymers have transformed the field of membrane-based gas separations over the past two decades. However, applying sorbent materials as membranes presents a unique challenge in quantifying emergent phenomena, such as how strongly sorbing penetrants influence transport of co-permeating species. These mechanistic features are of urgent concern for many current and emerging applications, yet they remain significantly understudied. In previous work, amine-functionalized PIM-1 (PIM-NH2) has proven to be an exemplar of these effects, exhibiting CO2/CH4 mixed-gas selectivities that are 2.6 times higher than selectivities calculated from pure-gas measurements. Here, we investigate the generalizability of this sorption-induced emergent phenomena through the synthesis of a novel amine-functional microporous poly(arylene ether) (PAE-NH2). The effects of amine functionalization on gas transport were analyzed through variable-temperature pure-gas sorption tests, ternary mixed-gas sorption modeling, and dual-mode sorption analysis for N2, CH4, CO2, and H2S. Compared to its nitrile-functional counterpart (PAE-CN), pure-gas sorption for PAE-NH2 was 69 % higher for CO2 and 26 % higher for H2S at 1 atm and 35 °C, suggesting increased affinity to both CO2 and H2S. However, the higher total sorption for H2S resulted in strong competitive sorption effects, decreasing permeability of both CO2 and CH4 for mixture experiments, which was reported in our complementary study on the mixed-gas separation performance of the same materials in this work. The strength of gas–polymer interactions were quantified by evaluating experimental isosteric heats of sorption for the acid gases in PIM-1, PIM-NH2, PAE-CN, and PAE-NH2. Amine-functionalized samples showed highly exothermic interactions, with minima in isosteric heats of approximately −44 kJ mol−1 for CO2 and −34 kJ mol−1 for H2S. Leveraging microporosity and amine-functionality in membranes are general approaches to access competitive sorption for many industrially relevant gas separations.
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DOI of Published Version
https://doi.org/10.1016/j.memsci.2024.122465
