Bioderived Ellagate-Based Metal–Organic Framework Photocatalysts for Photoenhanced Uranium Sequestration

To mitigate ecological and public health threats of radionuclides, functional metal–organic frameworks (MOFs) can serve as ideal platforms for separation of radionuclides, but bioderived MOFs with low-cost, environmentally friendly organic blocks are still desiring. In this work, a new kind of bioderived ellagic acid (EA)-based thorium-organic framework materials is proposed for the first time. It is demonstrated that Th-EA with π–π stacking interactions for supporting the robust framework possesses excellent structural stability in aqueous solutions at pH 2–11 and achieves a maximum adsorption capacity of 229.1 mg·g −1 at pH 5 for uranyl ion through an ion-exchange process. Notably, such a bioderived material can serve a photocatalyst to produce a large amount of hydrogen peroxide (H 2 O 2 ) (≈170.2 µmol·g −1 ·h −1 ) from water and oxygen under visible light irradiation, which is able to greatly improve the uranyl removal rate to 96.2% by transforming adsorbed uranyl into the insoluble studtite phase. Furthermore, Th-EA can also serve as both excellent adsorbents and photocatalysts to achieve high-efficiency and selective removal of uranium from radio-contaminated tailing groundwater. This work demonstrates the feasibility of bioderived MOF materials for enhanced nuclide separation and will inspire the development of more low-cost, environment-friendly functional materials.