Enhancing CO2 transport with plasma-functionalized ionic liquid membranes

The ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate treated with radiofrequency (RF) plasma, is proposed for functionalization and immobilization on polyethersulfone (PES) supports to form supported ionic liquid membranes (SILMs) for CO2 separation. The effects of treatment time and transmembrane pressure difference on CO2 permeance were evaluated. The best gas permeation performance is obtained when the treatment time is 10 min, and the transmembrane pressure difference is 0.25 MPa. Characterization of the materials by FTIR, XPS and NMR demonstrates that ILs is grafted with carboxyl groups and deprotonated through plasma treatment. A preliminary mechanism for the plasma treatment and facilitated transport of CO2 has been proposed based on this basis.