Selective Mineral Recovery from Seawater by Ion-Exchangeable Metal–Organic Framework Glasses

The transition to clean energy and sustainable technologies necessitates securing strategic materials, yet traditional land-based mining is increasingly unsustainable. Seawater holds immense potential as a mineral source, but its intricate ionic composition limits current extraction techniques. Here, we report a family of ion-exchangeable materials by grafting phosphate groups onto metal–organic framework glasses, followed by precise heat and aqueous treatments. This process introduces facile exchangeable ions and exposes active functional groups. The developed materials display progressively enhanced Mg 2+ /Ca 2+ selectivity as solution complexity increases from binary and ternary mixtures to synthetic seawater. Across three different natural seawater samples, the optimized material achieves Mg 2+ uptake of 7–10 mg g –1 and Li + uptake of 2–3 mg g –1 within 10 min, highlighting high capacity and rapid kinetics under realistic conditions. Quantitative mechanistic analysis reveals that ion exchange contributes to 72% of the total uptake, while 28% arises from phosphate functional groups and pore surface interactions. This dual-mode sorption mechanism underpins the material’s excellent selectivity and rate performance relative to a typical commercial resin. Our work thus presents a promising route for designing efficient adsorbents to extract valuable minerals from unconventional sources and help to secure the raw materials vital for a low-carbon future.