Computer simulation of water desalination through boron nitride nanotubes

Development of high-efficiency and low-cost seawater desalination technologies is critical to solving the global water crisis. Herein we report a fast water filtering method with high salt rejection by boron nitride nanotubes (BNNTs). The effect of the radius of BNNTs on water filtering and salt rejection was investigated by molecular dynamics (MD) simulation. Our simulation results demonstrate that fast water permeation and high salt rejection could be achieved by BNNT(7,7) under both high pressure and low pressure. The potential of mean force (PMF) of Na⁺ ion and water molecule through BNNT(7,7) further revealed the mechanism of seawater desalination by BNNT(7,7). Using BNNT(7,7) array, a 10 cm² nanotube membrane with 1.5 × 10¹³ pores per cm² will produce freshwater with a flow rate of 98 L per day per MPa under 100 MPa. Our study shows the potential application of BNNTs membrane for fast and efficient desalination.