• • Sulfonated covalent organic frameworks (S-COF) achieved a uranium sorption capacity of 31.5 mg/(g·day) from seawater, the highest reported to date, attributed to uranyl-recognition pockets and –SO3H units that form strong coordination with uranyl ions, demonstrating the potential of designed porous materials for selective uranium capture.
• • Amidoxime-based organic cages exhibited a sorption capacity of 11.97 mg/g after 30 days in seawater, highlighting the effectiveness of amidoxime groups in binding uranium, though the capacity is lower than S-COF, indicating trade-offs between capacity and kinetics.
• • A 'micro-redox reactor' strategy using copper-ion-mediated reactions (UO2²⁺ + Cu⁺ → UO2⁺ + Cu²⁺; 2UO2⁺ → UO2²⁺ + UO2(s)) enables continuous regeneration of binding sites by reducing adsorbed uranium to insoluble precipitates, thereby enhancing material reusability and long-term performance.
• • Electrochemical techniques can catalytically convert soluble U(VI) species into UO2 or bimetallic U(IV)-containing oxides via a two-electron transfer process, offering a new paradigm for uranium capture in complex wastewater systems, but their application in real seawater remains unproven.