Porous Graphene for Sea Water Desalination Considering the Effects of Fluorine/nitrogen Modification: A Molecular Dynamic Study

Abstract

Sea water desalination becomes more and more important as the consumption of fresh water. Forward osmosis (FO) is a novel technology for sea water or brackish water desalination, where a most important device, semi-permeable membrane, are required low resistance, high selection and inexpensive. In this study, based on molecular dynamic simulations, we explored the performance of porous graphene as the semi-permeable membrane for sea water desalination. Fluorine (F) and nitrogen (N) are adopted to optimize the property of graphene pore. We found that although pure pore have highest water flux (indicating lower resistance), N modified pore has the best selection due to the high electronegativity of N atoms. The about 60 L/cm2/h water flux and 100% solute rejection ratio confirm the graphene with N modified pores is good candidate as a semi-permeable membrane for sea water desalination.