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

Abstract

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 (CSMCRIHOF-1) of phenoxy-imine synthons conjugated to pyridyl tectons with varied pore dimensions of ∼3.6—∼3.8 Å, resulting in flow-through channels and 328 m2/g BET surface area. The CSMCRIHOF-1 shows a 3D robust network of hydrogen bonds (O−H···O, C−H···O, and O−H···N) supported by π-π stacking, exhibiting excellent hydrolytic stability under broad pH range (pH 1–10). Relative to other framework materials, the CSMCRIHOF-1 is easily processable and regenerable. Further processing of CSMCRIHOF-1 yields large-area free-standing thin films (TFCHs) of tunable thickness from 40 to 500 nm with enhanced surface area (550 m2/g). TFCH shows significant UES capacities of ∼11 mg/g within 5 days and 17.9 mg/g in 30 days from natural seawater.