Enhanced 2-D MOFs nanosheets/PES-g-PEG mixed matrix membrane for efficient CO2 separation

Abstract

Polymeric materials with polyethylene glycol (PEG) which contains ether oxygen groups are utilized as CO2 separation membranes due to the high selectivity, while suffered from low gas permeability owing to small free volume. The 2-D MOFs nanosheets showed excellent gas molecules permeance because of the unique pore structure and ultra-high specific surface with nanoscale thickness. In this work, the PES-g-PEG copolymer were prepared by thiol-ene click chemistry, the 2-D MOFs nanosheets were then introduced to fabricate MMMs. Benefitting from the effective transfer of MOFs nanosheets for CO2, the obtained MMMs exhibited greatly enhanced CO2 permeability (4 times higher than original PES-g-PEG membrane) and separation performance (71.7% increase of selectivity for CO2/N2 and 72.6% increase of selectivity for CO2/CH4). In addition, the introduction of 2-D MOFs nanosheets also improved the anti-plasticization capability and operation stability of the original PES-G-PEG membranes, the MMMs exhibited excellent stability for CO2 separation.