Large-area self-standing thin film of porous hydrogen-bonded organic framework for efficient uranium extraction from seawater

Uranium extraction from seawater (UES) efficiency is limited by the material design, such as U-selective binding sites, their uniform distribution, surface area exposure, diffusivity, and stability. Herein, we report a U-selective single-component hydrogen-bonded organic framework ((HOF)-H-CSMCRI-1) of phenoxy-imine synthons conju-gated to pyridyl tectons with varied pore dimensions of similar to 3.6-similar to 3.8 angstrom, resulting in flow-through channels and 328 m(2)/g BET surface area. The (HOF)-H-CSMCRI-1 shows a 3D robust network of hydrogen bonds (O-H center dot center dot center dot O, C-H center dot center dot center dot O, and O-H center dot center dot center dot N) supported by pi-pi stacking, exhibiting excellent hydrolytic stability under broad pH range (pH 1-10). Relative to other framework materials, the (HOF)-H-CSMCRI-1 is easily processable and regenerable. Further processing of (HOF)-H-CSMCRI-1 yields large-area free-standing thin films (TFCHs) of tunable thickness from 40 to 500 nm with enhanced surface area (550 m(2)/g). TFCH shows significant UES capacities of similar to 11 mg/g within 5 days and 17.9 mg/g in 30 days from natural seawater.

Automated summary

In this study, a new method for uranium extraction from seawater is reported. By designing an organic framework material with selective binding sites, high extraction efficiency and stability are achieved. The large-area thin films produced from this material have tunable thickness and increased surface area, enabling effective uranium extraction from seawater.