High-performance microporous organic solvent nanofiltration composite membrane prepared from a contorted maleimidoanthracene biscatechol monomer

• A rigid bicyclic tetrahydroxy monomer THMIA was used to prepare TFC OSN membranes. • The formed polyarylate layer shows enhanced microporosity and ultra-thin characters. • The optimal membrane shows a methanol permeance of 20.4 LMH/bar and MWCO of 289 Da. • The membrane performs good in APIs separation and homogeneous catalysts recovery. In recent years, organic solvent nanofiltration (OSN) technology has garnered significant interest owing to its eco-friendly and low-carbon characteristics, offering efficient molecular separation in organic solvents. However, most scalable OSN membranes reported still suffer from the inherent permeability and selectivity trade-off effect, which inevitably hampers their industrial applications. In this study, we design and synthesize a novel bicyclic molecule 2,3,6,7-tetrahydroxy-maleimidoanthracene (THMIA), featuring a rigid, contorted configuration as well as four phenolic reactive groups. By exclusively employing THMIA reacted with trimesoyl chloride (TMC) through interfacial polymerization on a PAN substrate, we fabricate advanced TFC OSN membranes. The optimal THMIA/TMC composite membrane exhibits a high methanol permeance of 20.4 LMH/bar and good solutes retention ability with MWCO value as low as 289 Da. This outstanding separation performance should arise from the synergistic effects of crumpled membrane surface, elevated microporosity and ultra-thin thickness (∼14 nm) of the polyarylate nanofilm. In addition, the THMIA/TMC membrane shows promising prospects for the fast and reliable separation of various active pharmaceutical ingredients (APIs) and recovery of homogeneous organometallic catalyst from organic media. Overall, this study offers some new insights into utilization of the rigid bicyclic molecule as an aqueous IP monomer to facilely construct highly perm-selective OSN membranes.