Combined Superbase Ionic Liquid Approach to Separate CO2 from Flue Gas

Adam J. Greer, S. F. Rebecca Taylor, Helen Daly, Johan Jacquemin, Christopher Hardacre

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
32 Downloads (Pure)


Superbase ionic liquids (ILs) with a trihexyltetradecylphosphonium cation and a benzimidazolide ([P66614][Benzim]) or tetrazolide ([P66614][Tetz]) anion were investigated in a dual-IL system allowing the selective capture and separation of CO2 and SO2, respectively, under realistic gas concentrations. The results show that [P66614][Tetz] is capable of efficiently capturing SO2 in preference to CO2 and thus, in a stepwise separation process, protects [P66614][Benzim] from the negative effects of the highly acidic contaminant. This results in [P66614][Benzim] maintaining >53% of its original CO2 uptake capacity after 30 absorption/desorption cycles in comparison to the 89% decrease observed after 11 cycles when [P66614][Tetz] was not present. Characterization of the ILs post exposure revealed that small amounts of SO2 were irreversibly absorbed to the [Benzim]− anion responsible for the decrease in CO2 capacity. While optimization of this dual-IL system is required, this feasibility study demonstrates that [P66614][Tetz] is a suitable sorbent for reversibly capturing SO2 and significantly extending the lifetime of [P66614][Benzim] for CO2 uptake.
Original languageEnglish
Pages (from-to)9453 - 9459
Number of pages7
JournalACS Sustainable Chemistry & Engineering
Early online date13 Jul 2022
Publication statusPublished (in print/issue) - 25 Jul 2022

Bibliographical note

Author not at UU at time of submission, no acceptance date. Set acc date as 1st of month of first publication to enable compliance section and exception set as OA.


  • ionic liquids
  • CO2 capture
  • SO2 capture
  • flue gas
  • scrubber


Dive into the research topics of 'Combined Superbase Ionic Liquid Approach to Separate CO2 from Flue Gas'. Together they form a unique fingerprint.

Cite this