Bio-inspired ferromagnetic graphene oxide/magnetic ionic liquid membrane for highly efficient CO2 separation

Abstract

The design of high-performance CO2 separation membrane with both ultrathin thickness and robust stability remains a challenge. Herein, inspired by the function of AQP1 within the biological membrane for gas selectivity, an untrathin (∼45 nm) graphene oxide/magnetic ionic liquid membrane (GO/MILM) is prepared by infusing [P6,6,6,14][FeCl4] into the 2D nano-space of stacked GO nanosheets. Due to the affinity difference of various gases in MIL, the synergy of electrostatic and magnetic interaction between GO and MIL, ordered arrangement of magnetic anions [FeCl4]− in the nanospace between GO nanosheets is achieved, resulting efficient CO2 separation. The molecular dynamics simulation manifests the separation mechanism. In consequence, the optimized GO/MILM exhibits fast CO2 permeance of 82.9 GPU with high CO2/N2 and CO2/CH4 selectivity of 180 and 76, respectively, surpassing most of reported membranes. Moreover, a stable performance more than 7 days renders the GO/MILM great potential for industrial CO2 separation. This bioinspired strategy may provide a potential to fabricate 2D membranes integrating high-performance, low cost and ultrathin thickness for CO2 capture.