Understanding the desalination performance of seawater passing through the lamellar BN membranes: Effect of interlayer spacing and concentration

•The salt rejection rate was mainly affected by the effective interlayer spacing.•The adsorption and hydrogen bonds interactions would affect water permeability.•Higher concentration of NaCl would narrow the difference of water permeability. Due to its smaller surface tension and greater wetting degree, BN-based membranes have exhibited promising application prospect in water treatment and seawater desalination. In this work, boron nitride nanosheets were employed to establish lamellar BN membranes layer by layer. By using non-equilibrium molecular dynamics simulations (NEMD), we evaluated the influence of interlayer spacing on the desalination performance of BN membranes. We also evaluated the relationship between the water permeability and the concentration of the feed solution. The simulation results showed that the water permeability of BN membrane first decreased and then increased with the interlayer spacing, it reached the minimum at the interlayer spacing of 1.1 nm, with a turning point at the same time. This is due to the strong interaction between water molecules and BN. What’s more, with the increase of the concentration of the feed solution, the hindering effect of ions on the transport of water molecules gradually decreases, the difference between water permeability in systems with different interlayer spacing decreases gradually.