Nanoconfined CO2-philic ionic liquid in laminated g-C3N4 membrane for the highly efficient separation of CO2

Membrane separation technology has received widespread attention in the field of gas separation because of small footprint, convenient operation and low energy consumption. However, membranes separation are subject to a trade-off between permeance (or permeability) and selectivity. Herein, a novel kind of supported oinic liquid membrane (SILM) was constructed by nanoconfined 1-ethyl-3-methylimidazole acetate ([EMIm][AcO], IL) in the two-dimentional (2D) channels of the g-C 3 N 4 laminated membrane for CO 2 /N 2 and CO 2 /CH 4 separation. Due to the nanoconfinement of ILs in 2D g-C 3 N 4 laminated membrane and the appropriate nanofluidic channels constructed by the g-C 3 N 4 nanosheets, the as-prepared g-C 3 N 4 SILM possesses outstanding permeance and selectivity for CO 2 in separation of CO 2 /N 2 and CO 2 /CH 4 . The experimental result shows that g-C 3 N 4 SILM possesses maximum CO 2 permeance of 992.97 GPU in separation of CO 2 /N 2 and 1160.52 GPU in separation of CO 2 /CH 4 under 1 bar, 25℃. Meanwhile the resultant g-C 3 N 4 SILM shows excellent selectivity for CO 2 /N 2 (52.49) and CO 2 /CH 4 (48.41) respectively. Moreover, the resulted g-C 3 N 4 SILM displays excellent thermal stability and durability. After 60 h test, its separation performance has no obvious change. The findings of our study demonstrate that nanoconfined the IL into the 2D g-C 3 N 4 is a novel strategy for the preparation of high-performance supported liquid membrane for the separation of CO 2 /N 2 and CO 2 /CH 4 .