High-throughput thin-film composite membrane via interfacial polymerization using monomers of ultra-low concentration on tannic acid – Copper interlayer for organic solvent nanofiltration

Abstract In this work, a novel organic solvent nanofiltration (OSN) membrane was engineered precisely via interfacial polymerization on the surface of an interlayer which was in-situ constructed using tannic acid – copper (TA-Cu) complex on the surface of a polyimide substrate membrane, and then was followed by crosslinking and activation procedures. The most promising aspect of this work is the high separation and solvent permeation performances due to the ultrathin film obtained in the interfacial polymerization reaction using ultra-low concentration monomers, 0.025 wt% aqueous m-phenylenediamine (MPD) and 0.0050 wt% trimesoyl chloride (TMC) in organic solution, respectively The optimized interlayered thin film composite (TFC) OSN membrane achieved a rejection of 98.36% for Rose Bengal (RB, 1017 Da) and a DMF permeance of 150.05 L m−2h−1 MPa−1 for 100 mg L−1 RB-DMF solution, much higher than most of the state-of-the-art literature works. Furthermore, after a 75 h’ filtration, it remained a 98.7% rejection for RB of the RB-DMF solution, proving a high resistance to strong polar solvent. Meanwhile, it has an average surface roughness of less than 4.5 nm, a thickness of about 15 nm for the PA skin layer. This OSN membrane fabrication strategy is much economical and much environmentally friendly, and shows great potential for the application in the separation of organic solvent systems.