Nanofiltration membranes review: Recent advances and future prospects

• State-of-the-art overview of NF membranes and its approach on membrane fabrication and modification
• The trend and progress in the development and application of NF membranes over the past 5 years
• Fouling and fouling mitigation in the application of NF membrane
• Future direction in NF membrane development

Nanofiltration (NF) membranes have come a long way since it was first introduced during the late 80's. With properties in between those of ultrafiltration (UF) and reverse osmosis (RO), NF membranes have been used in many interesting applications especially in water and wastewater treatment and desalination. Other applications include those in pharmaceutical and biotechnology, food and non-aqueous types of application. This review will comprehensively look at the recent advances in NF membranes research. Significant development has taken place in terms of the fundamental understanding of the transport mechanism in NF membranes. This has been translated into predictive modeling based on the modified extended Nernst–Planck equation. Similarly various methods have been used to fabricate improved NF membranes especially through interfacial polymerization incorporating nanoparticles and other additives, UV grafting/photografting, electron beam irradiation, plasma treatment and layer-by-layer modification. New applications were also explored in many industries. However fouling is still a prevalent issue that may hinder successful application of NF membranes. Efforts towards NF fouling prevention and mitigation have also been reported. The review ends with several recommendations on the future prospect of NF membranes research and development.