Facile and rapid assembly of high-performance tannic acid thin-film nanofiltration membranes via Fe³⁺ intermediated regulation and coordination

Non-polyamide (non-PA) thin-film composite nanofiltration (TFC-NF) membranes have received tremendous attention in recent years, but their development is strongly hindered by the complicated fabrication process and the trade-off between permeability and selectivity. Here, we report a highly perm-selective non-PA TFC-NF membrane through 2-minute rapid assembly of tannic acid (TA) on hydrolyzed polyacrylonitrile (PAN) substrate via Fe3+ intermediated regulation and coordination. The optimized membrane with a molecular weight cut off of ~390 Da showed high rejections for salts in a sequence of Na2SO4 (90.2%) > MgSO4 (83.4%) > NaCl (50.0%) > MgCl2 (35.2%) and desirable rejections for organic pollutants (e.g. >99.0% dyes, 92.2% streptomycin and 81.8% chloramphenicol) while maintaining a pure water permeability of as high as 13.6 L·m−2·h−1·bar−1, which clearly outperforms the reported non-PA membranes. In addition, the assembled TFC membrane showed excellent antifouling performance and reasonable structural stability against operation pressure and solution alkalinity. These results are highly promising and indicate a great potential for the membrane to be used in practical nanofiltration application, e.g. water purification and wastewater reclamation. Our work outlines the production of novel high-performance non-PA membrane with a fast fabrication process in a green chemistry context