Reverse interfacial polymerization of o-tolidine for stable organic solvent nanofiltration

To overcome the poor organic solvent resistance of conventional polymer membranes, this study developed a robust thin-film composite (TFC) membrane via reverse interfacial polymerization on a polyethylene (PE) substrate. Using o-tolidine (OT) and 1,3,5-benzenetricarbonyl chloride (TMC) as monomers, a high-permeability and highly crosslinked polyamide (PA) selective layer was successfully constructed. The influence of composition of the co-solvent, OT and TMC concentration on membrane morphology, surface chemistry, and separation performance was systematically investigated. The optimized TFC membrane exhibited excellent DMF permeance (4.03 Lm −2 h −1 bar −1 ) and high rejection (99.5%) of methyl blue, attributed to the formation of a compact yet permeable PA layer and electrostatic repulsion effects. Furthermore, the membrane demonstrated excellent long-term stability under harsh solvent conditions and elevated pressure, showcasing superior chemical and mechanical resilience. This work offers a practical and scalable approach for developing advanced solvent-resistant membranes suitable for dye removal in organic media.