Hierarchically self-supporting porous ultrathin films with aligned photothermal nanosheets for ultrafast uranium extraction from seawater

Seawater is the world's largest reservoir of uranium and, hence, uranium in seawater is one of the most sustainable sources of nuclear fuel. Poly(amidoxime) (PAO)-based adsorbents hold promise for uranium extraction from seawater but have not been industrialized because of their insufficient uranium extraction efficiency. Herein, hierarchically porous ultrathin PAO films with aligned graphene oxide nanosheets were prepared by Marangoni flow-driven superspreading and evaluated as adsorbents for uranium extraction from seawater efficiently. The best-performing film exhibited high photothermal conversion, short uranium diffusion path, and excellent salt-shrinkage resistance. These features endow the film with a high uranium adsorption capacity of 10.4 mg (-1) for natural seawater after 10 days, with an ultrafast rate of 1.04 mg g(-1) day(-1) exceeding those of previously reported recoverable AO-based adsorbents. Given the upscalability of the film fabrication method and regenerability of the developed films, the present study paves the way for uranium of extraction from seawater efficiently.