High metal ions separation performance of nanofiltration membrane regulated by polyethyleneamine and sodium lauryl sulphate via reversed interfacial polymerization

Nanofiltration (NF) membrane technology holds unique application potential in the metal ion separation due to its high efficiency and low cost. However, the present NF membranes are facing the contradictory challenge of high water permeance and efficient separation for metal ions. In this study, we reported a NF membrane fabricated by amine-rich polymer polyethyleneamine (PVAm) with sodium lauryl sulphate (SDS) as the aqueous phase additive via reversed interfacial polymerization (IP). Based on the polymerization strategy and the role of amine groups and SDS, the fabricated membranes showed thinner and denser selection layer with positively-charged surface. Moreover, the membrane exhibited high water permeance (14.7 L m -2 h −1 bar −1 ), as well as excellent rejection performance towards divalent metal ions, including significant Li + /Mg 2+ separation (selective factor of 12.1) and high rejection rates for metal ions (Co 2+ 96.5 % and Sr 2+ 93.4 %), which are higher than most reported NF membranes. We believe this research provides valuable insights for the application of NF membrane in the field of salt-lakes lithium extraction and nuclide management.