The Influence of Polycation and Counter-Anion Nature on the Properties of Poly(ionic liquid)-Based Membranes for CO2 Separation

The current investigation is focused on the development of composite membranes based on polymeric ionic liquids (PILs) containing imidazolium and pyridinium polycations with various counterions, including hexafluorophosphate, tetrafluoroborate, and bis(trifluoromethylsulfonyl)imide. A combination of spectroscopic methods was used to identify the synthesized PILs and characterize their interaction with carbon dioxide. The density and surface free energy of polymers were performed by wettability measurements, and the results are in good agreement with the permeability and selectivity obtained within the gas transport tests. It was shown that the membranes with a selective layer based on PILs exhibit relatively high permeability with CO2 and high ideal selectivity CO2/CH4 and CO2/N-2. Additionally, it was found that the type of an anion significantly affects the performance of the obtained membranes, with the most pronounced effect from bis-triflimide-based polymers, showing the highest permeability coefficient. These results provide valuable insights into the design and optimization of PIL-based membranes for natural and flue gas treatment.

Automated summary

The current research is focused on developing composite membranes based on polymeric ionic liquids (PILs) containing imidazolium and pyridinium polycations with different counterions. Spectroscopic methods were used to identify the synthesized PILs and study their interaction with carbon dioxide. Wettability measurements were carried out to determine the density and surface free energy of the polymers, which correlated well with the permeability and selectivity observed in gas transport tests. The study found that membranes with selective layers based on PILs exhibited high permeability to CO2 and high ideal selectivity for CO2/CH4 and CO2/N-2. Additionally, the type of counterion had a significant effect on the membrane performance, with polymers based on bis-triflimide showing the highest permeability coefficient. These findings provide valuable insights for the design and optimization of PIL-based membranes for natural and flue gas treatment.