Nanoporous MoS Membrane for Water Desalination: A Molecular Dynamics Study.

Molybdenum disulfide (MoS), a two-dimensional (2D) material, promises better desalination efficiency, benefiting from the small diffusion length. While the monolayer nanoporous MoS membrane has great potential in the reverse osmosis (RO) desalination membrane, multilayer MoS membranes are more feasible to synthesize and economical than the monolayer MoS membrane. Building on the monolayer MoS membrane knowledge, the effects of the multilayer MoS membrane in water desalination were explored, and the results showed that increasing the pore size from 3 to 6 Å resulted in higher permeability but with lower salt rejection. The salt rejection increases from 85% in a monolayer MoS membrane to about 98% in a trilayer MoS membrane. When averaged over all three types of membranes studied, the ions rejection follows the trend of trilayer > bilayer > monolayer. Besides, a narrow layer separation was found to play an important role in the successful rejection of salt ions in bilayer and trilayer membranes. This study aims to provide a collective understanding of this high permiselective MoS membrane's realization for water desalination, and the findings showed that the water permeability of the MoS monolayer membrane was in the order of magnitude greater than that of the conventional RO membrane and the nanoporous MoS membrane can have an important place in the purification of water.