All-Atoms Molecular Dynamics Study of Multilayer Holey Graphene Frameworks for Membrane Distillation*

Membrane distillation (MD) is an emerging water desalination technique which has critical advantages over traditional pressure-driven membrane-based counterparts, including a 100% salt rejection rate. The challenge still remains in designing a membrane for MD that allows for a high level of permeate flux with superior anti-wetting and mechanical properties. Recently, holey graphene frameworks have gained much popularity due to its intrinsic network porous structure. Their low tortuosity, tunable hydrophobicity, and wide range of pore size should also make them good candidates for MD. In this study, an all-atom molecular dynamics model is developed to simulate a flexible holey graphene framework, with varied interlayer spacing and pore size as a membrane for MD. Furthermore, we investigate the permeation performance when the framework surface is doped with fluorine atoms, which has been shown to exhibit super-hydrophobicity and low thermal conductivity. GPU acceleration and OpenMP multithreading are used to increase simulation speed. The overall results shall be presented at the conference.