Factors Affecting the Separation Performance in Ionic Liquid/Cu Nanocomposite Membranes for Facilitated CO2 Transport.

Based on data reported for facilitated CO2 transport membranes, we analyzed the factors that would enhance their performance by utilizing an ionic liquid (IL)/Cu nanoparticle (NP) composite. The previously reported ILs were BMIM NO3, BMIM BF4, MOIM BF4, and HMIM NO3. Compared with neat ILs, the selectivity of the ILs/Cu increased with the enhancement of permeance. We investigated the effect of the percentage of free ions in ILs and the size of the Cu NPs on CO2 separation performance. In addition, we found that the viscosity and steric effect of ILs played an important role in enhancing separation performance. In this regard, CO2 easily dissolved in the low-viscosity ILs, and their low steric effect allowed the ILs to readily interact with the surface of the Cu NPs.