High CO2 solubility in ionic liquids and a tetraalkylammonium-based poly(ionic liquid)

Abstract

Carbon dioxide (CO 2 ) absorption in several imidazolium-based ionic liquids (ILs), pyridinium-based ionic liquids and a tetraalkylammonium-based poly(ionic liquid) (PIL), poly [(p-vinylbenzyl) trimethylammonium hexafluorophosphate] P[[VBTMA] [PF 6 ], was studied. The trend of CO 2 solubility in all of the ILs increases dramatically with decreasing absorption temperature. Based on the same bis(triflamide) [Tf 2 N] anion, imidazolium, pyridinium and trihexyltetradecylphosphonium-based ionic liquids all show relatively similar CO 2 solubilities, which were higher than for the [ES] anion. The highest CO 2 absorption was found in a poly(ionic liquid) P[[VBTMA] [PF 6 ]], however, the monomer also showed higher CO 2 capacity than the other ionic liquids. The poly(ionic liquid) is remarkable in that it can adsorb 77% of its body weight of CO 2 with a selectivity over nitrogen of 70 : 1. The absorbed CO 2 gas can be readily desorbed from ionic liquids and poly(ionic liquid) and the selectivity for CO 2 over N 2 was consistent over repeated cycles. The materials can be reused several times for consecutive sorption/desorption cycles, without loss of performance in a large-scale reactor and therefore represent serious candidates for use in commercial adsorbers.

Polymeric ionic liquids for CO2 capture and separation: potential, progress and challenges

“…PIL-8b probed by Supasitmongkol and Styring was also found to readily desorb CO 2 gas. 77 Flue gas stack from power plants typically contain only 15 % concentration of CO 2 as compared to nitrogen, therefore, CO 2 /N 2 selectivity is of foremost importance. Many groups working in the field of PILs extensively studied the selectivity of CO 2 over other gases and found that CO 2 sorption was selective and no weight gain was noticed on exposure of PILs to N 2 or O 2 under similar conditions signifying that PILs can selectively absorb CO 2 .…”

Imidazolium‐Based Poly(ionic liquid)s as New Alternatives for CO2 Capture

“…[10,11] It was discovered that converting ionic monomers into polymeric forms resulted in materials with elevated CO 2 capture efficiency compared to room-temperature ionic liquids. [9,10,12,13] Moreover, it was detected that poly(ionic liquid)s (PILs) possess higher CO 2 sorption capacity than the corresponding monomers [12,14] and they are very selective in terms of separation of CO 2 from mixtures of N 2 /CO 2 , CH 4 /CO 2 and O 2 /CO 2 . [9,10,12,13] Moreover, it was detected that poly(ionic liquid)s (PILs) possess higher CO 2 sorption capacity than the corresponding monomers [12,14] and they are very selective in terms of separation of CO 2 from mixtures of N 2 /CO 2 , CH 4 /CO 2 and O 2 /CO 2 .…”

Integrated CO2 Capture and Utilization Using Non-Thermal Plasmolysis

“…This composition sits well within the range expected as an output from coal fired power stations, for example, found in the UK (Naims, 2016;von der Assen et al, 2016). This PSA system makes use of a cheap and robust solid sorbent, which is based on previously reported poly-ionic liquid sorbents by this group (Supasitmongkol and Styring, 2010;Dowson et al, 2016), which selectively adsorbs CO2 on pressurization of the gas stream. As the pressure is released, the N2 and CO2 desorb from the sorbent surface at different rates, thus creating two separate streams; one rich in N2 followed by one rich in CO2.…”