Ionic liquid-functionalized antibiofouling nanofiltration membranes

Abstract

Nanofiltration membranes hold great potential for water treatment applications, but are susceptible to fouling issues. In this study, we demonstrate the fabrication of NF membranes with high permeability, high rejection, antibiofouling and scaling resistance. The membrane was prepared through interfacial polymerization by doping the aqueous phase with 1-aminoethyl-3-methylimidazolium tetrafluoroborate ionic liquid. The TFC-0.2 membrane exhibited a more open nanoporous structure, resulting in an increased permeability from 5 ± 0.5 L·m−2·h−1·bar−1 (LMH/Bar) to 11.1 ± 0.4 LMH/Bar, while maintaining a comparable salt rejection performance to the original TFC membrane. Additionally, the TFC-0.2 membrane demonstrated excellent retention performance, with a removal efficiency exceeding 90 % for emerging contaminants such as antibiotics and PFOA. Notably, the TFC-0.2 membrane exhibited significant differences in the rejection of Na2SO4 and CaCl2, indicating its strong resistance to gypsum fouling. Furthermore, it is worth highlighting that the TFC-0.2 membrane displayed remarkable antibiofouling performance due to the bactericidal properties of AMIT. This capability allowed for the sterilization of bacteria at the early stage of attachment to the membrane surface, effectively mitigating biofouling. The findings of this study offer a simple yet effective strategy for fabricating high-performance nanofiltration membranes with exceptional antifouling properties.