Exploring Water/Ion Transport through the Polarized Lamellar Channels

Abstract

The charge features of membranes are considered to have a significant influence on the optimization of their desalination performance. Two-dimensional hexagon boron nitride (h-BN) sheets with abundant partial charge distribution should show a special influence on the water/ion transport. However, the nanochannel made of stacked polar h-BN sheets as a desalination membrane is rarely discussed. In this work, a molecular dynamics (MD) simulation was adopted to explore the influence of the atomic partial charges on the desalination performance of the lamellar h-BN channel. Simulation results show that the Coulomb interaction between water/ions and the channels affects the passage of water/ion through the lamellar h-BN channel. The ion and water transport rates decrease noticeably when passing through the strongly polarized membrane. The influence of electrostatic interactions on water/ion transport decreases with the interlayer height increasing. Moreover, the data also reveal a novelty finding that the salt rejection of the polarized channel increases proportionally with the length of the channel increasing, along with the decrease in water and ion flux. These observations provide some valuable suggestions for the design of membranes with excellent desalination performance by manipulating the electrostatic properties of membranes, the interlayer height, or the length of the channel.