Theoretical performance of nanofiltration membranes for wastewater treatment

Mechanisms of ionic transport in nanofiltration are poorly known. Modelling can be used to predict membrane performance, to reveal separation mechanisms, to select appropriate membranes, and to design processes. Several models have been proposed to describe nanofiltration membranes. Some models rely on simple concepts, while other models are more complex and require sophisticated solution techniques. Here, we review predictive models used for characterizing nanofiltration membranes for the separation of wastewater. The most popular model uses the extended Nernst-Planck equation, which describes the ionic transport mechanisms in details. Results obtained by using the extended Nernst-Planck equation show that the performance of nanofiltration membranes is strongly dependent on charge, steric, and dielectric effects.