The oceans offer a virtually infinite source of uranium and could sustain nuclear power technology in terms of fuel supply. However, the current processes to extract uranium from seawater remain neither economically viable nor efficient enough to compete with uranium ore mining. Microporous polymers are emerging materials for the adsorption of uranyl ions due to their rich binding sites, but they still fall short of satisfactory performance. Here, inspired by the ubiquitous fractal structure in biology that is favourable for mass and fluid transfer, we describe a hierarchical porous membrane based on polymers of intrinsic microporosity that can capture uranium in seawater. This biomimetic membrane allows for rapid diffusion of uranium species, leading to a 20-fold higher uranium adsorption capacity in a uranium-spiked water solution (32 ppm) than the membrane with only intrinsic microporosity. Furthermore, in natural seawater, the membrane can extract as much uranium as 9.03 mg g⁻¹ after four weeks. This work suggests a strategy to be extended to the rational design of a large family of microporous polymer adsorbents that could fulfil the vast promise of the oceans to fuel a reliable and potentially sustainable energy source.

海洋提供了几乎无限的铀源，可以在燃料供应方面维持核电技术。然而，目前从海水中提取铀的工艺在经济上仍然不可行，效率也不足以与铀矿开采竞争。微孔聚合物由于其丰富的结合位点而成为吸附铀酰离子的新兴材料，但它们仍然缺乏令人满意的性能。在这里，受生物学中普遍存在的有利于质量和流体传递的分形结构的启发，我们描述了一种基于固有微孔聚合物的分级多孔膜，可以捕获海水中的铀。这种仿生膜允许铀物质快速扩散，导致在掺铀水溶液 (32 ppm) 中铀的吸附能力比仅具有固有微孔的膜高 20 倍。此外，在天然海水中，该膜可提取多达 9.03 mg g 的铀四个星期后^-1。这项工作提出了一种策略，可以扩展到一大类微孔聚合物吸附剂的合理设计，这些吸附剂可以实现海洋为可靠和潜在的可持续能源提供燃料的广阔前景。