Biomimetic Slit-Shaped Fiber Interpenetration Enables Superadsorptive COF Aerogels for Uranium Extraction

Oceans hold vast uranium (U) resources, while extraction is severely challenged by the ultralow U concentration and abundant competing ions. Covalent organic frameworks (COFs) offer promise due to their tunable functional groups and photocatalytic activity for U reduction. However, conventional COF materials face significant limitations, such as micropore-induced mass transfer resistance and impractical powder recycling. To overcome these challenges, we engineered biomimetic superadsorptive COF aerogels (SACAs) with biomimetic slit-shaped pores via a bubble-assisted bidirectional ice-templating methodology. This unique approach, involving dynamic regulation of the gas–liquid interface, constructs a hierarchically porous material featuring micro/mesopores for abundant active sites and interconnected macropores for rapid mass transport. The resulting SACA exhibits an ultralow density (11.2 mg/cm 3 ), high elasticity, and exceptional underwater stability (withstanding >500 compression cycles). Critically, the biomimetic slit-shaped porous structure inherent to this design provides superior fluid transport kinetics and an ultrahigh equilibrium adsorption capacity (1776.86 mg/g) under visible light irradiation. In the dynamic adsorption test, the SACA exhibited a constant extraction capacity under varied flux rates, alongside excellent recyclability and outstanding adsorption selectivity. The successful development of such materials with biomimetic slit-shaped pores will drive innovation in environmental, energy, and electronic applications, showcasing promising prospects for practical applications.