Atomistic Simulation of Water and Salt Transport In RO Membrane Active Layers

As part of a combined computational and experimental effort to develop new RO membrane materials, we have carried out detailed equilibrium and nonequilibrium molecular dynamics simulations of the aromatic polyamide active layers of reverse osmosis desalination membranes.  Simulations carried out at low salt concentration yield hydraulic permeabilities in good agreement with experimental results.  Statistical issues make direct simulation of salt rejection impractical, but we will describe the observed distribution and transport mechanisms of salt ions in the polymer.