Influence of chemical functionalization on the CO2/N2 separation performance of porous graphene membranes

The separation of CO2 from a mixture of CO2 and N-2 using a porous graphene membrane was investigated using molecular dynamics (MD) simulations. The effects of chemical functionalization of the graphene sheet and pore rim on the gas separation performance of porous graphene membranes were examined. It was found that chemical functionalization of the graphene sheet can increase the absorption ability of CO2, while chemical functionalization of the pore rim can significantly improve the selectivity of CO2 over N-2. The results show that the porous graphene membrane with all-N modified pore-16 exhibits a higher CO2 selectivity over N-2 (similar to 11) due to the enhanced electrostatic interactions compared to the unmodified graphene membrane. This demonstrates the potential use of functionalized porous graphene as single-atom-thick membrane for CO2 and N-2 separation. We provide an effective way to improve the gas separation performance of porous graphene membranes, which may be useful for designing new concept membranes for other gases.