CO$_2$ separation using a porous graphene/IL membrane

We investigated the separation of CO$_2$ from CO$_2$/O$_2$ mixture using a porous graphene/ionic liquid (IL) membrane. By performing extensive non-equilibrium molecular dynamics (NEMD) simulations, we observed dramatic CO$_2$ separation with a 0.99 nm graphene nanopore. By calculating the density distribution, we show that a strong layering of the ionic liquid is observed near the 0.99 nm graphene nanopore, while such a strong layering is not observed in the larger 2.22 nm diameter pore. The strong layering induces a near perfect blockage of O$_2$ molecules from diffusing into the ionic liquid. Void analysis shows that the layering of ionic liquid serving as a blockage for O$_2$ molecules does not hinder CO$_2$ solvation in the ionic liquid.