ltration membranes review: Recent advances and future prospects

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. © 2014 Elsevier B.V. All rights reserved.

NF membranes, as a subset of pressure-driven liquid membrane processes, have had successful applications in various industries. The solute transport in NF membranes is generally controlled by steric, Donnan, dielectric and transport effects and this has led to the development of predictive modeling based on the extended Nernst–Planck equation. The model has been successfully used in many studies. Methods for NF membranes fabrication have also been quite successful in producing membranes with better selectivity, and improved flux and fouling propensity. The main method is still based on interfacial polymerization to produce thin-film composite or nanocomposite membranes. Introduction of nanomaterials in the thin film has had a significant effect on membrane performance. Due to its varied selectivity, NF membranes have also been successful in water and wastewater treatment, desalination, pharmaceutical, biotechnology and food applications. However problems still persist in fouling control and mitigation. Future works should focus on developing better membranes and new innovative applications while improving the ability to control, reduce and mitigate fouling.