A First-Principles Study on the Uptake of Uranium from Seawater in Dimethylglyoxime-Intercalated Layered Double Hydroxides

Withthe rapid depletion of terrestrial uranium ores, extraction of uranium from the seawater reservoir has become vital for sustainable nuclear energy. In this context, the intercalation of dimethylglyoxime (DMG) into layered double hydroxides (LDHs) represents a promising strategy for the extraction of seawater uranium. In this study, nine distinct DMG-intercalated M 2 N-LDH(001) systems were constructed, and their UO 2 2+ capture performance and competitive selectivity against seawater cations (Na +, K +, Mg 2+, and Ca 2+ ) were systematically evaluated by means of first-principles calculations. Among the constructed DMG-intercalated M 2 N-LDH(001) systems, the DMG-intercalated Ni 2 Fe-LDH(001) system emerged as a promising uranium adsorbent from seawater, exhibiting the strongest capture ability and exceptional selectivity. Notably, a structural activation of UO 2 2+ was observed within the DMG-intercalated Ni 2 Fe- and Ni 2 Co-LDH(001), where the intrinsically linear O═U═O moiety undergoes a spontaneous distortion into a bent configuration. Electronic structure analyses reveal that the orbital hybridization between the U 5f orbitals of UO 2 2+ and the O 2p orbitals from both the LDH host layers and the DMG ligands drives the formation of a highly stable interfacial dual-coordination mode, endowing the material with a superior UO 2 2+ affinity. This theoretical work could provide insights into the design and screening of efficient adsorbents for the extraction of uranium from seawater.