Cross-Linked Poly(ethylene oxide) Ion Gels Containing Functionalized Imidazolium Ionic Liquids as Carbon Dioxide Separation Membranes

Journal Article · Sun Aug 05 00:00:00 EDT 2018 · Industrial and Engineering Chemistry Research

DOI:https://doi.org/10.1021/acs.iecr.8b02739· OSTI ID:1482986

Kusuma, Victor A.  ^[1]; Macala, Megan K. ^[1]; Baker, James S. ^[2]; Hopkinson, David ^[2]

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1. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); AECOM Corp., Pittsburgh, PA (United States)
2. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

1,3-Substituted imidazolium bis(trifluoromethylsulfonyl)imide (Tf₂N) ionic liquids (ILs) were incorporated at 40 and 60 vol % loading into a cross-linked poly(ethylene oxide) polymer network to create ion gels for carbon dioxide (CO₂)-selective gas separation membranes. The ILs plasticize the poly(ethylene oxide)-based polymer to increase its gas permeability. Compared to the base polymer, with a CO₂ permeability of 145 barrer and a CO₂ against nitrogen (N₂) selectivity of 47, the highest CO₂ permeability achieved was 530 barrer coupled with a CO₂/N₂ selectivity of 31 by having 60 vol % [1-ethyl-3-methylimidazolium][Tf₂N]. The extent of gas permeability improvement depends on the cation’s terminal substituent. Substituents that promote additional noncovalent intermolecular interactions, such as hydroxyl, benzyl, and nitrile, can reduce the gas diffusivity by reducing the polymer chain mobility. Here, while n-alkyl, branched alkyl, and oligo(ethylene glycol) substituents can significantly increase the gas permeability, the shortest substituents (such as ethyl) were the most effective because they promote high ionic charge density.

• Research Organization: National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy (FE)
• Grant/Contract Number: FE0004000
• OSTI ID: 1482986
• Journal Information: Industrial and Engineering Chemistry Research, Vol. 57, Issue 34; ISSN 0888-5885
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY