Nanoporous MoS2 Membrane for Water Desalination: A Molecular Dynamics Study

Molybdenum disulfide (MoS2), a two-dimensional (2D) material, promises better desalination efficiency, benefiting from the small diffusion length. While the monolayer nanoporous MoS2 membrane has great potential in the reverse osmosis (RO) desalination membrane, multilayer MoS2 membranes are more feasible to synthesize and economical than the monolayer MoS2 membrane. Building on the monolayer MoS2 membrane knowledge, the effects of the multilayer MoS2 membrane in water desalination were explored, and the results showed that increasing the pore size from 3 to 6 angstrom resulted in higher permeability but with lower salt rejection. The salt rejection increases from 85% in a monolayer MoS2 membrane to about 98% in a trilayer MoS2 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 MoS2 membrane's realization for water desalination, and the findings showed that the water permeability of the MoS2 monolayer membrane was in the order of magnitude greater than that of the conventional RO membrane and the nanoporous MoS2 membrane can have an important place in the purification of water.

Automated summary

Molybdenum disulfide (MoS2) as a two-dimensional material shows potential in water desalination with multilayer membranes having higher salt rejection rate compared to monolayer. As the number of layers increases, the membrane's salt rejection rate increases but with decreased permeability. Narrow layer separation plays a crucial role in effectively rejecting salt ions.