Simulation of cations separation through charged porous graphene membrane

Graphene membranes have shown promising prospects in cations separation; however, the underlying separation mechanisms remain elusive. In this study, the permeation of five cations through graphene membranes with variable pore size and surface charge density is explored by molecular simulations. It reveals that negatively charged graphene draws cations closer to the membrane. While positively charged graphene together with small-sized pores generates larger energy barriers, promoting the separation of different cation pairs. Result shows that the separation mechanisms are dominated by electrostatic interaction and steric hindrance. This theoretical work could guide the design of graphene membrane for desalination.