Hierarchical Triple-Channel Architectures Unlock Scalable and High-Efficient Uranium Extraction from Seawater

Abstract 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—combining millimeter-scale honeycomb channels, sub-millimeter transverse channels, and intrinsic micropores—is 100 times thicker than conventional hydrogels, enabling practical marine deployment with high adsorption performance. Mass transfer analysis and COMSOL simulations reveal two synergistic pathways: (1) accelerated laminar flow through macrochannels (Reynolds number Re = 1981.52) and (2) diffusion-enhanced transport within microchannels (effective diffusivity Deff = 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 record uranium uptake of 14.69 mg U/g over 35 days—the highest among macroscale polyamidoxime adsorbents without external energy input—and demonstrates exceptional ion selectivity, reusability, and cost efficiency. These findings demonstrate that hierarchical triple-channel architectures can unlock efficient and scalable uranium extraction from seawater.