Marangoni-driven self-assembly of hierarchical PAO/PVA membranes for highly efficient uranium extraction from seawater

Extraction of uranium from seawater offers a sustainable approach for nuclear fuel supply. Poly(amidoxime) (PAO) adsorbents have emerged as a highly promising extraction approach. However, there are still challenges that hinder the practical application of PAO-based adsorbents in considering the extraction performance and durability. To address these challenges, we developed a mechanically robust PAO/polyvinyl alcohol (PAO/PVA) composite superspreading membrane (SSPP) via Marangoni effect-driven interfacial self-assembly. This strategy constructs hierarchically porous structures with gradient pore sizes, promoting efficient ion transport and access to functional adsorption sites. The PVA integration enhances hydrophilicity and forms a hydrogen-bonded network that prevents structural shrinkage, while boosting mechanical strength, making the adsorbent more suitable for practical use. Consequently, the optimized membrane achieves a high uranium adsorption capacity of 7.42 mg g−1 in natural seawater within 10 days. This work provides an interfacial self-assembly strategy for advanced extraction membranes and demonstrates significant potential for sustainable uranium extraction from seawater.