Nanofiltration as a Pretreatment Step in Seawater Desalination: A Review

One of the main applications of nanofiltration (NF) is in the pretreatment stage of seawater desalination. NF has high rejection rates for divalent ions and could eliminate the scaling species that pose serious fouling problems in seawater desalination. This review comprehensively examines recent advances in NF membrane research in seawater desalination. Significant progress has been made in understanding the mechanism of solute transport through NF membranes and has resulted in the development of predictive models based on the Spiegler–Kedem model and the modified Nernst–Planck equation. The contributions of each type of transport mechanism through NF membranes, i.e., convection, diffusion, and electro-migration, have been reported. A review of recent progress made in the development of integrated NF membrane and seawater desalination processes is included. Work related to membrane fouling, which is a key problem in NF, is also discussed.