Highly permeable ionic liquid 1-butyl-3-methylimidazoliumtetrafluoroborate (BMIMBF4)/CuO composite membrane for CO2 separation

Abstract

An ionic liquid (IL) 1-butyl-3-methylimidazoliumtetrafluoroborate (BMIM+BF4-)/CuO composite was prepared for CO2 transport membranes. CuO nanoparticles (NPs) were successfully generated in BMIM+BF4-. The formation of CuO NPs was ascribed to the favorable interaction between the ions of BMIM+BF4- and the surface of the CuO particles. To confirm the coordination behavior of the BMIM+BF4-/CuO membrane, TGA and FT-Raman spectroscopy were employed. The ideal CO2/N2 selectivity in the case of the composite material was 21.0, with a CO2 permeance of 52.4 GPU, while the neat BMIM+BF4- membrane showed a selectivity of 5.0 and a CO2 permeance of 17.0 GPU. The enhanced separation performance was attributed to (1) the synergistic effect of well-dispersed CuO nanoparticles, resulting in enhanced CO2 solubility due to the increased surface of the oxide particle layer and (2) the abundant free ions in BMIM+BF4-.