Investigation of CO2 Sorption Characteristics of Imidazolium Ionic Liquid Crystals

Journal Article · Sun Sep 28 00:00:00 EDT 2025 · Journal of Molecular Liquids

DOI:https://doi.org/10.1016/j.molliq.2025.128524· OSTI ID:3011908

Redwine, Grace ^[1]; Strange, Nicholas ^[2]; Quine, Cullen ^[3]; Leick, Noemi ^[3]; Gennett, Thomas ^[3]

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1. Colorado School of Mines
2. SLAC National Accelerator Laboratory
3. National Renewable Energy Lab., Golden, CO (United States)

This work is focused on advancing of the understanding the carbon dioxide (CO2) sorption characteristics of imidazolium ionic liquid crystals based on the 1-alkyl-3-methylimidazolium (Cnmim) ionic liquid family. Specifically, the mechanism of sorption across the melting, liquid crystal, and isotropic liquid transitions is investigated for 1-tetradecyl-3-methylimidazolium tetrafluoroborate (BF4-) and hexafluorophosphate (PF6-). A unique reversible CO2 occlusion was observed in 1-tetradecyl-3-methylimidazolium tetrafluoroborate (C14mim BF4) under rapid temperature quench from the liquid phases to the solid phase, while complete desorption occurred upon heating above the melting point (40 degrees C). In situ wide-angle x-ray scattering revealed that the lamellar structure of C14mim BF4 liquid crystal phases provides a high concentration of dynamically accessible anion and cation interaction sites for CO2, facilitating CO2 occlusion upon rapid solidification. The selective occlusion of CO2 in C14mim BF4 suggests a new mechanism for CO2 sorption processes.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Hydrogen Fuel Cell Technologies Office (HFTO)
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 3011908
• Report Number(s): NREL/JA-5900-95995
• Journal Information: Journal of Molecular Liquids, Journal Name: Journal of Molecular Liquids Journal Issue: Part C Vol. 437
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
carbon dioxide
gas sorption
ionic liquids