Hierarchical triple-channel architectures unlock scalable and high-efficient uranium extraction from seawater

The ocean holds ~4.5 billion tons of uranium, a vast yet underexploited resource for sustainable nuclear energy. However, current seawater uranium adsorbents suffer from poor macroscale structures, limited mass transfer, and inefficient functional group utilization. Here, we report a bioinspired honeycomb-like polyamidoxime adsorbent featuring an interconnected hierarchical triple-channel architecture (HTC-PAO) that addresses these challenges. Its hierarchical structure incorporates millimeter-scale honeycomb channels, sub-millimeter transverse channels, and intrinsic micropores. The adsorbent is 100 times thicker than conventional hydrogels, enabling practical deployment in marine environments while maintaining excellent adsorption performance. Mass transfer analysis and COMSOL simulations reveal two synergistic pathways: (1) accelerated laminar flow through macrochannels (Reynolds number Re = 922.50) and (2) diffusion-enhanced transport within microchannels (effective diffusivity D_eff = 6.96 × 10^-9 vs. 1.74 × 10^-9 m²/s), working together to maximize uranium capture and functional group accessibility. As a result, HTC-PAO achieves a uranium adsorption capacity of 14.69 mg/g over 35 days under conditions without external energy input, while also showing high ion selectivity, reusability, and cost efficiency. These findings demonstrate that the hierarchical triple-channel architecture enables highly efficient and scalable uranium extraction from seawater.