Polyelectrolyte Grafted MOFs Enable Conjugated Membranes for Molecular Separations in Dual Solvent Systems

Organic solvent nanofiltration (OSN) is a green and cost-effective technique for valuable small active molecule reclamation from organic solvent systems. To date, it remains challenging to develop highly permeable and precisely sieving nanoporous membranes capable of working with dual solvent systems. Herein, we design polar-group-enriched conjugated nanoporous membranes (CNMs) to achieve ultrahigh performance for dual solvents. The CNMs contain sodium polymethacrylate-grafted-UiO-66 metal-organic framework (MOF) nanoparticles, which can create additional interfacial nano-pores for solvent permeation, enhance solvent affinity, and partially reduce the swelling of the CNMs. Consequently, our membranes exhibit ultrahigh permeances in dual solvents (EtOH 53.9 L m–2 h–1 bar–1, H2O 58.1 L m–2 h–1 bar–1, pentane 244.0 L m–2 h–1 bar–1 and hexane 172.9 L m–2 h–1 bar–1) with molecular weight cut-off below 400 Da, which is superior to many state-of-the-art OSN membranes, demonstrating potential for diverse applications from pharmaceutical industry to chemical engineering.