Hydrodynamic and Mass Transfer Modeling of Ion Transport through Nanofiltration Membranes

The present work deals with the development of a mathematical model for predicting the transfer mechanism of ions through nanoporous medium. The model considers concentration polarization phenomenon to study its influence on ion separation. The developed model is a combination of two transport models: the first one is based on the extended Nernst–Planck equation while the second is based on convection-diffusion as well as Navier-Stokes equations. The model equations were solved numerically utilizing CFD techniques for solving quite stiff equation in two subdomains including feed and membrane. The modeling findings rigorously predict local variation of ionic concentrations, flux and individual ion rejections along a rectangular cross flow membrane module. The simulation results revealed that the model is more accurate than previous model for prediction of ion separation performance.