Vertically Aligned Polyamidoxime/Graphene Oxide Hybrid Sheets’ Membrane for Ultrafast and Selective Extraction of Uranium from Seawater

With the continuous research and development of amidoxime (AO)‐based adsorbents, industrialization production of uranium from seawater gradually becomes a reality. However, the currently available AO‐based adsorbents still suffer from low adsorption rate and poor selectivity. Herein, vertically aligned polyamioxime–graphene oxide (VA‐PG) sheet membrane is fabricated by directional freeze casting. The run‐through microchannels contribute to the free diffusion of uranyl ions (UO22+), leading to the fast adsorption kinetics. Furthermore, partially reduced graphene oxide allows high photothermal conversion efficiency and rapid in‐plane heat transfer, resulting in the fast temperature rise under simulated sunlight irradiation. Because of the endothermic behavior of UO22+, light‐irradiated VA‐PG can simultaneously satisfy the requirements of high adsorption capacity (13.63 mg‐U g‐Ads−1), high adsorption rate (0.43 mg g−1 day−1), and excellent selectivity toward U(VI) over V(V) (U/V = 1.24) in natural seawater, indicating the right direction for a breakthrough in the field of uranium extraction from seawater. Vertically aligned polyamidoxime (PAO)–graphene oxide (GO) (VA‐PG) sheet membranes are fabricated by directional freeze casting for uranium extraction from seawater. Run‐through microchannels facilitate diffusion of UO22+. Partially reduced GO in VA‐PG allows high solar energy photothermal conversion and rapid in‐plane heat transfer. Consequently, light‐irradiated VA‐PG simultaneously satisfies the requirements of high adsorption capacity, adsorption rate, and U(VI)/V(V) selectivity.