Integration of Zwitterionic Polymer Nanoparticles in Interfacial Polymerization for Ion Separation

A thin-film nanocomposite (TFN) membrane was developed by integrating zwitterionic polymeric nanoparticles into the active layer of the membranes. High surface area zwitterionic polymeric nanoparticles (370 m2/g) were developed through distillation-precipitation polymerization (DPP). Sodium 4-vinylbenzenesulfonate (SVBS) was used as the monomer and N,N′-methylenebis(acrylamide) (MBAAm) utilized as the cross-linking agent. l-cysteine (l-Cys) was tethered to these matrices through thiol-ene reaction. The as-synthesized zwitterionic P(MBAAm-co-SVBS)@l-Cys nanoparticles were dispersed into the organic solution of trimesoyl chloride (TMC) to be integrated into the polyamide (PA) selective layer of thin film nanofiltration membranes. The PA layer was synthesized by interfacial polymerization through the reaction of 2% (w/v) of piperazine (PIP) in the aqueous phase and 0.15% (w/v) of the TMC solution. The fabricated TFN membranes exhibited pure water permeability (Jw) of 11.4 L/m2h bar and salt rejection value of 97.6% and 16.9%, for sodium sulfate and sodium chloride, respectively. The fabricated membranes demonstrated metal ion removal efficiencies of 99.48% and 95.67% for Pb2+ and Cd2+ ions, respectively.