Amine-functionalized zirconium–ellagate framework for enhanced water permeance and ion selectivity in thin-film nanocomposite nanofiltration membranes

초록

Thin-film nanocomposite (TFN) nanofiltration (NF) membranes incorporating metal–organic frameworks (MOFs) have emerged as a promising strategy to overcome the conventional permeability–selectivity trade-off. However, poor interfacial compatibility between MOFs and the polyamide selective layer often leads to nonselective voids that limit separation performance. This work presents the first use of a zirconium–ellagate framework (SU-102) as a filler in TFN membranes, whose performance was further enhanced through post-synthetic amine functionalization with ethylenediamine (EDA) via a Schiff-base reaction. The introduced amine groups increased membrane hydrophilicity and improved interfacial interactions with the polyamide layer, resulting in a thinner selective layer. The optimized TFN-EDA-30 membrane exhibited a high water permeance of 15.7 L m−2 h−1 bar−1 and a NaCl/Na<inf>2</inf>SO<inf>4</inf> separation factor of 69.4, surpassing the established permeability–selectivity upper bound of MOF–TFN NF membranes and outperforming commercial benchmarks. Molecular dynamics simulations confirmed that EDA functionalization strengthens water–MOF interactions and suppresses anion mobility, supporting the molecular mechanism underlying enhanced water permeance and ion selectivity. These results establish amine-functionalized SU-102 as an effective and sustainable filler for advancing high-performance TFN membrane design in ion separation applications. © 2025 Elsevier Ltd.

키워드