Ionic liquid assisted interfacial polymerization of β-Cyclodextrin into thin-film composite membranes for organic solvent nanofiltration

β-cyclodextrin (β-CD), with intrinsic nano-cavity, is a promising monomer to construct thin-film composite (TFC) membranes for molecular separations. Nevertheless, interfacially polymerize β-CD into continuous membranes is challenging due to the low reactivity of hydroxyl groups. To address this issue, in this work, ionic liquid (IL) has been introduced into the interfacial polymerization (IP) process of β-CD and trimesoyl chloride (TMC), forming high-quality TFC membranes for organic solvent nanofiltration (OSN). Investigations have been done into how IL effects membrane structure and separation performance. In contrast to traditional β-CD-TMC TFC membrane, the β-CD-IL-TMC TFC membrane possesses upgraded crosslinking, continuity, stability, and OSN separation property. The best β-CD-IL-TMC membrane has an ethanol permeance of up to 57.01 L m−2h−1 MPa−1 and Naphthol green B rejection rate of 99.98% and can sustain a stable separation performance within 20-hour test, indicating the fabricated β-CD-IL-TMC membranes have advantage of separating and purifying organic solvent.