Mussel-inspired polyphenol-metal composite nanofiltration membranes with enhanced performance

In this study, we successfully developed a novel mussel-inspired composite loose nanofiltration (LNF) membrane through a facile “one-step” membrane-forming method. The membrane was constructed by co-depositing tannic acid (TA) and polyethyleneimine (PEI) at controlled mass ratios on a polyvinylidene fluoride (PVDF) substrate, mimicking mussel adhesion chemistry. To further enhance membrane performance, we introduced a secondary modification strategy involving metal ion (M + ) coordination via dopamine (DA)-mediated cross-linking. Experimental results demonstrate that the performance of the mussel-inspired LNF membrane was significantly affected by varying the TA/PEI ratio. The T-P-P/DA-Fe 3+ membrane exhibited an impressive pure water flux of 5517.2 L/(m²·h), high dye rejection rate of 99.6 %, notably salt-dye separation selectivity (α) of 708.4, indicating great potential for application in the treatment of textile wastewater.