Robust biomimetic MOF featuring a negative pocket for precise recognition of uranyl enabling an ultrahigh U/V selectivity and a rapid uranium extraction from seawater

Low U/V selectivity and long extraction time remain the major obstacles in the field of uranium extraction from seawater, as both can largely reduce the uranium extraction ability of an adsorbent. We present a robust biomimetic metal-organic framework (MOF) material, designated ECUT-74, engineered through innovative incorporation of helical rod-like secondary building units. This structural design introduces a protein-mimicking uranyl-binding motif that enables precise recognition of uranyl, leading to a benchmark U/V selectivity of 104. When applied to real seawater (3.3 μg L-1), ECUT-74 demonstrates an ultrafast uranium extraction with a record-making extraction ability of 16 mg g-1 in just one day and 22.6 mg g-1 in five days, along with an extremely low uptake for other metal ions (less than 2 mg g-1). The robust nature of this MOF allows for a good reusability for uranium extraction from seawater. All these merits strongly suggest the superior application of ECUT-74 for uranium extraction from seawater.