Deep Eutectic Solvent-Mediated Engineering of Polyamide Membranes for High-Performance Loose Nanofiltration

With growing demands for the efficient separation and recovery of high-value components, loose nanofiltration (LNF) has emerged as a promising membrane technology. However, the development of LNF membranes presents ongoing challenges in achieving precise structural control through conventional water/alkane interfacial polymerization. Herein, we developed an innovative anhydrous interfacial polymerization strategy for fabricating high-performance polyamide membranes that can be tailored for LNF applications. This approach employs a deep eutectic solvent (DES) as the amine monomer solvent, interface regulator, and polymerization mediator. In contrast to water/alkane interfacial systems, the polymerization between piperazine and trimesoyl chloride at the DES/cyclohexane interface facilitates the formation of an ultrathin loose polyamide layer with precisely controlled pore architecture. The resultant membrane exhibits a high water permeance of 48 L m^-2 h^-1 bar^-1 and exceptional molecular sieving capability, including unprecedented dye desalination efficiency (NaCl/Congo red selectivity of 954) and effective antibiotic desalination (NaCl/rifampicin selectivity of 72.7), surpassing state-of-the-art nanofiltration membranes. This work offers a breakthrough in both membrane technology development and interfacial polymerization methodology, enabling energy-efficient separation processes through innovative membrane design.