Computer simulations of water flux and salt permeability of the reverse osmosis FT-30 aromatic polyamide membrane

The relative permeability of salt to water across an atomistic model of the FT-30 reverse osmosis (RO) membrane is studied using molecular dynamics (MD) simulations. The membrane model is built using a heuristic approach and gives a membrane density, water solubility and flux that are in good accord with the experimental values. The salt permeability is calculated from inhomogeneous solubility–diffusion theory using ion pathways from non-equilibrium targeted MD simulations, yielding an estimated salt rejection of 99.9% that is similar to the experimental value. The encouraging agreement with experimental data of FT-30 membrane suggests that MD simulations based on atomic models offer a useful way to support the experimental exploration of RO membrane development.