Ag-based nanocapsule-regulated interfacial polymerization Enables synchronous nanostructure towards high-performance nanofiltration membrane for sustainable water remediation

In this work, Ag-based compound nanorods were molecularly synthesized followed by the incorporation into PA active layer through interfacial polymerization (IP) process. This strategy achieved the concurrent construction of molecular sieving architecture and tunable surface function, by precisely controlling the release of zero dimensional Ag nanoparticles (AgNPs, -5 nm), via in situ decomposition of the pH-responsive compounds serving as sacrificial nanocapsules. Featuring favorable interactions and sizes, the released ultrafine AgNPs serves as a quasi-molecule-scale regulator to generate the thin-film nanocomposite (TFN) membrane with wrinkled surface microstructures and loose internal architecture, due to the adjusted diffusion rate of amine monomers toward the organic phase during IP, while endowing the resultant membrane with superior antifouling/antibiofouling properties. The newly-developed AgNPs embedded PA (AgNPs@PA) TFN membrane exhibited a high water permeance of 10.4 L m(-2) h(-1) bar(-1) (more than twice that of the pristine PA [4.5 L m(-2) h(-1) bar(-1)]) with a rejection ratio of 97.7% for Na2SO4, performing a competitive desalination property among the state-of-the-art nanofiltration membranes. The proposed technique for tuning the membrane microstructure opens opportunities for developing high-performance nanofiltration membranes for energy-efficient water remediation and treatment applications.