Miao Lei

High-salinity waters, including seawater, brines, and saline radioactive effluents, contain recoverable uranium or require uranium removal, but their complex chemistry complicates both capture and regeneration. Under seawater-relevant conditions, U(VI) occurs mainly as uranyl carbonate complexes and ternary uranyl carbonate complexes containing Ca²⁺ or Mg²⁺ rather than as free UO₂²⁺. Selective separation therefore depends on coupled transport, hydration-shell reorganization, carbonate displacement, and interfacial coordination. Conventional sorbents largely optimize binding strength and adsorption capacity, often at the expense of harsh stripping and secondary waste. This review frames thermoresponsive uranium separation as a coupled aqueous-speciation, interfacial-state, and process-design problem. It examines how LCST and UCST transitions, polymer-brush reorganization, hydration-layer reconstruction, pore gating, and localized photothermal heating regulate access to binding sites and release pathways. Polymer brushes, hydrogels and microgels, membranes and nanochannels, ion-imprinted magnetic composites, and MXene-based hybrids are critically compared using cycle-level criteria, including U/V selectivity, switching time, regeneration demand, energy input, fouling resistance, material loss, synthesis reproducibility, and environmental performance. Particular emphasis is placed on distinguishing genuine structural gating from the generic effects of temperature on diffusion, ligand exchange, and adsorption equilibria. Current evidence supports the feasibility of programmable capture–release interfaces but remains limited by matrix-dependent transition windows, incomplete mechanistic attribution, scarce quantitative energy and temperature-gradient data, short cycling tests, and limited device-scale validation. Progress will require standardized testing in realistic saline matrices and complete capture–release mass and energy balances rather than evaluation by maximum adsorption capacity alone.

With the rising importance of nuclear energy in the global energy landscape, the sustainable development of uranium resources has garnered increasing attention. Salt lake brine, as an unconventional uranium source, holds significant potential due to its relatively high uranium concentration and the co-occurrence of valuable elements such as lithium, boron, and potassium. However, the high salinity and complex ionic composition of brine environments pose considerable challenges for the efficient and selective extraction of uranium. In recent years, the rapid advancement of novel adsorbent materials has provided promising technological pathways for uranium extraction from salt lake brine. This review systematically summarizes recent progress in the application of inorganic and carbon-based materials, organic polymers with functional group modifications, and biomass-derived and green adsorbents in this field. The construction strategies, performance characteristics, and adsorption mechanisms of these materials are discussed in detail, with particular emphasis on their selectivity and stability under complex saline conditions. Furthermore, the application status and future prospects of emerging materials and techniques—such as photocatalysis and electrochemistry—are also explored. This review aims to offer theoretical insights and technical references to support the sustainable exploitation of uranium resources from salt lake brines.