Recent advances on cellulose-based nanofiltration membranes and their applications in drinking water purification: A review

Nanofiltration membranes play a crucial role in advanced water treatment, however, a number of challenges remain in their application, such as difficulties in controlling membrane fouling and membrane pore size, as well as membrane material biodegradability. An emerging trend currently underway is to develop a natural/biodegradable polymer-based membrane that is sustainable while achieving high flux and separation efficiency. Cellulose-based membrane materials are green, low-cost, and energy-saving, which offer the potential to replace traditional petrochemical-based membrane materials. This review article provides a comprehensive and critical review of the design approach in composite nanofiltration membranes, green membrane materials, and the major features and advantages in the preparation of cellulose-based composite nanofiltration membranes. The focus is on the recent developments (especially after 2015) in cellulose nanofiltration membranes based on molecular-level design approaches for advanced water treatment, with the aim of further insights into cellulose membrane pore structure-filtration performance. In addition, the applications of cellulose nanofiltration membranes in seawater desalination, drinking water softening, and oil-water separation are presented. Furthermore, a brief investigation of the industrial development and applications of cellulose nanofiltration membranes is given, as well as the current limitations and the future directions are discussed.