Desalination Performance of MoS2 Membranes with Different Single-Pore Sizes: A Molecular Dynamics Simulation Study.

Abstract

Utilizing molecular dynamics simulations, we examined how varying pore sizes affect the desalination capabilities of MoS2 membranes while keeping the total pore area constant. The total pore area within a MoS2 nanosheet was maintained at 200 Å2, and the single-pore areas were varied, approximately 20, 30, 40, 50, and 60 Å2. By comparing the water flux and ion rejection rates, we identified the optimal single-pore area for MoS2 membrane desalination. Our simulation results revealed that as the single-pore area expanded, the water flux increased, the velocity of water molecules passing the pores accelerated, the energy barrier decreased, and the number of water molecules within the pores rose, particularly between 30 and 40 Å2. Balancing water flux and rejection rates, we found that a MoS2 membrane with a single-pore area of 40 Å2 offered the most effective water treatment performance. Furthermore, the ion rejection rate of MoS2 membranes was lower for ions with lower valences. This was attributed to the fact that higher-valence ions possess greater masses and radii, leading to slower transmembrane rates and higher transmembrane energy barriers. These insights may serve as theoretical guidance for future applications of MoS2 membranes in water treatment.