From dense packing to porous layered POMOFs for ultra-efficient seawater uranium extraction

Efficient and selective uranium extraction from seawater (UES) is crucial for nuclear fuel sustainability but is challenged by low concentration, complex matrix, and biofouling. Here, we construct two POMOFs with distinct architectures: a dense D-W₁₀-MOF and a porous layered P-W₁₀-MOF. Taking advantage of the precise O···O distance (4.17 Å) matching uranyl bidentate coordination, open porous framework, and enhanced mass transfer, P-W₁₀-MOF achieves a record-breaking Langmuir-fitted theoretical maximum uranium adsorption capacity (q_max) of 3197.5 mg·g⁻¹ in simulated seawater adsorption tests, along with outstanding selectivity (U/V ≈ 10³) and cycling stability. By contrast, D-W₁₀-MOF delivers a substantially lower q_max of 961.5 mg·g⁻¹ due to hindered access to coordination sites. XAFS, XPS and DFT results confirm an equatorial U-O coordination number of 5.0 ± 0.4, consisting of three O donors from the W₁₀ cluster and two bidentate carbonate O donors. P-W₁₀-MOF also exhibits strong antibacterial activity, and a preliminary life cycle assessment guides green synthesis. This work provides a paradigm for designing high-performance uranium adsorbents by clarifying the geometric structure and framework structure of the components.