Co-construction of molecular-level uranyl-specific ?nano-holes? with amidoxime and amino groups on natural bamboo strips for specifically capturing uranium from seawater

Efficiently capturing of uranium (VI) [U(VI)] from seawater elicits unparalleled attraction for sustaining the uplifted requirement for nuclear fuel. However, obtaining the abundant U(VI) resource from seawater has always seriously restricted by competitive adsorption from higher concentrations of competitors, especially vanadium (V) [V(V)]. Herein, based on amidoximized natural bamboo strips with hierarchical porous structure, the molecular-level uranyl-specific nano-holes was co-constructed by the intramolecular hydrogen bonds for specifically trapping U(VI) from seawater. Manipulating the branched degrees of amino groups enabled the creation of a series of the molecular-level uranyl-specific nano-holes that exhibit ultrahigh affinity and selective adsorption of U(VI) with a adsorption capacity 1.8 fold higher compared to that of V(V) after 30 days floating in the Yellow Sea basin, conquering the long-term challenge of the competitive adsorption of V(V) for amidoxime-based adsorbents applied to extract U(VI) from seawater. The diameter of the molecular-level uranyl-specific nano-holes is approximately 12.07 A, significantly larger than (UO2)3(OH)3+ (10.37 A) and smaller than HV10O28 5-, thereby exhibiting specifically trapping of U(VI) in a series of adsorption experiments with different U (VI)-V(V) ratios. Besides, the adsorption model based on the combination of experimental and theoretical results is accompanied by hydrogen bond breaking and coordination bond formation.

Automated summary

Efficiently capturing U(VI) from seawater has always been restricted by competitive adsorption from higher concentrations of V(V). In this study, a molecular-level uranyl-specific nano-holes were constructed using amidoximized natural bamboo strips, enabling the specific trapping of U(VI) from seawater with ultrahigh affinity and selective adsorption.