Accelerating CO2 transport through nanoconfined magnetic ionic liquid in laminated BN membrane

Abstract The development of highly effective and durable CO2 separation membrane is still a challenge for the carbon capture and storage. Herein, a novel BN nanosheets supported magnetic ionic liquid membrane (BN-SMILM) is constructed by nanoconfining magnetic ionic liquid (MIL) [P6,6,6,14][FeCl4] to the two-dimentional (2D) nanochannels of laminated BN membrane. The 2D nanochannels provide a well support and restricted space for the MIL. The nanoconfinement effect makes the magnetic [FeCl4]- anions align along the center of 2D BN nanochannels, leading to selectively accelerate the CO2 transport. The nanoconfinement effect and CO2 separation mechanism are further explicated by the molecular dynamic simulations. As a result, compared with the polymer supported MIL membrane, the as-prepared BN-SMILM exhibits better CO2 separation performance, with CO2 permeability of about 227 Barrer and CO2/N2 selectivity of 90 that is above the 2008 Robeson upper-bound. The BN-SMILM also presents excellent long-term stability after 7 days operation, revealing the promising applications in CO2 separation. This work provides a new strategy to prepare high-performance supported liquid membrane materials towards practical environmental and energy application.