Retarded Interfacial Formation of Polyamine-Based Nanofiltration Membranes with Pyromellitic Acid: Separation, Acid Stability, and Antifouling Performance

Crosslinked and additive-added polyamide thin-film composite (TFC) nanofiltration (NF) membranes formed by the conventional interfacial polymerization (IP) process have shown good performances. However, studies on polyamine TFC NF membrane prepared via an adjusted IP process with low-cost acid ligands as an interfacial additive for improved liquid-based separation are still lagging. In this regard, a polyamine-based TFC NF membrane synthesized by retarding the interfacial polymerization (IP) process with pyromellitic acid (PMA) (a polycarboxylate acid ligand) is herein reported. The PMA-adjusted membrane displayed a superb range of pure water fluxes from 9.8 to 20.4 L m–2 h–1 bar–1, with the best-performed membrane achieving up to 95.1% for Na2SO4 rejection. Thus, the water permeability of the PMA-TFC membrane is ∼2.4 times as high as the control TFC membrane. The best-performed PMA-TFC membrane showed good hydrophilicity, pressure resistance, and long-term filtration stability. In addition, the membrane structural stability was maintained with ∼3.9% declination in salt rejection after 30 days of immersion in 0.1 M HNO3 solution. Also, an impressive fouling resistance was achieved after three-cycle of bovine serum albumin fouling tests. This work, therefore, offers a more feasible way of designing polyamine-based NF membranes with good prospects in water reuse and nitric acid-generating wastewater treatment application.