Poly(vinylbenzyl chloride)-based poly(ionic liquids) as membranes for CO 2 capture from flue gas
Over the last decade, membrane-based CO 2 capture using ionic liquids (ILs) has been demonstrated as a promising technology. However, elaborative synthesis of monomers and long-term instability of IL-based composite membranes have so far limited their industrial relevance. In this paper, novel membr...
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Published in | Journal of materials chemistry. A, Materials for energy and sustainability Vol. 5; no. 37; pp. 19808 - 19818 |
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Main Authors | , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
2017
|
Online Access | Get full text |
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Summary: | Over the last decade, membrane-based CO
2
capture using ionic liquids (ILs) has been demonstrated as a promising technology. However, elaborative synthesis of monomers and long-term instability of IL-based composite membranes have so far limited their industrial relevance. In this paper, novel membranes are introduced for CO
2
separation using poly(ionic liquids) (PILs) based on polyvinylbenzyl chloride (PVBC). Three PIL-based membranes were prepared as thin-film composites (TFC) by solvent casting with subsequent sealing. They were tested for the CO
2
removal from synthetic flue gas. An ammonium-derivatised PVBC-analogue was prepared as a first PIL-type by polymerisation of an IL monomer, whereas two other PILs, respectively with hydroxyethyl ammonium and pyrrolidinium cations, were obtained using a modification of commercial PVBC. Introduction of bis(trifluoromethylsulfonyl)imide (Tf
2
N) anions was accomplished by metathesis. A thorough characterisation of the material structure, composition, membrane morphology and gas separation properties demonstrates that the presence of hydroxyl groups in the polycation enhanced the interaction with CO
2
molecules. The mixed-gas selectivity increases with the higher positive charge on the cation species (hydroxyethyl-dimethylammonium > trimethylammonium > pyrrolidinium). More importantly, experiments performed in humidified conditions particularly revealed a doubled CO
2
permeance and a 20–30% increased selectivity in comparison to dry conditions. These developments are spurring the application of PIL-based TFC membranes for CO
2
capture from flue gas streams. |
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ISSN: | 2050-7488 2050-7496 |
DOI: | 10.1039/C7TA05171A |