A comprehensive study of recent advances, challenges and factors of nanofiltration membrane in various industrial applications

Nanofiltration (NF) membrane was first introduced in the late 1980s, which shows the membrane properties between ultrafiltration and reverse osmosis . Impressively, the NF membrane represents significant unique properties such as enhanced selectivity toward divalent/polyvalent ions while enabling permeability of monovalent ions and small molecules <100 Da. These properties play an increasingly large role in a variety of applications, such as waste water treatment (desalination, water softening, and fluoride removal), pharmaceutical and biotechnology uses, food and non-aqueous applications, and others. Beyond all of its unique properties, NF has to negotiate a few limitations such as temperature stability, flux/rejection trade-offs, and membrane fouling . Hence, adjusting surface chemistries and morphologies through several modification processes enables NF membranes to be tuned for a certain application to achieve optimal performances. The physical/chemical interaction occurring at the surface or interface in the NF surface modification process has been proven to effectively regulate and improve crucial parameters of the NF membrane. Herein, this review will be conducted as an in-depth study of the recent advances and achievements of NF membranes. Meanwhile, several typical surface modification processes have all been utilized to produce better NF membrane properties. Finally, further prospects for various NF applications with significant challenges are highlighted in detail. • Significant developments in NF technology are explored to a range of commercial applications. • The major advantages and drawbacks of NF technology are addressed from a future view-point. • A general discussion takes place regarding the elements evaluating the development of NF fouling during desalination. • An in-depth examination of several surface modification methods are discussed to enhance the separation performances of NF membranes.