A facile method to fabricate anti-fouling nanofiltration membrane with aminated lignin

Nanofiltration (NF) membrane separates materials with molecular weight of 200–2000 Da effectively. However, the membrane fouling is inevitable, which can deteriorate the membrane performance and service life. Meanwhile, the common additives improving the anti-fouling performance may bear high cost and involve complex synthesis process. In this work, biomass material lignin is chemically modified (LG-NH2) and utilized in the interfacial polymerization process to improve the hydrophilicity and ant-fouling property of NF membranes. Both the reversible and irreversible fouling are reduced. In addition, the LG-NH2 optimizes the membrane pore size and increases the permeability of NF membrane, while the rejection to Na2SO4 is marginally affected, although the rejection to MgCl2 drops. Finally, the NF membrane is applied for biogas slurry valorization and demonstrates great potential. This work thus not only provides a convenient and cheap method to fabricate anti-fouling NF membranes, but also a potential route for the utilization of biomass, i.e., lignin and biogas slurry.