Stable colloidal dispersion cross-linked Janus hydrogel films for simultaneous efficient uranium capture and seawater desalination.

The integration of seawater uranium extraction and seawater desalination is not only of strategic significance for safeguarding nuclear fuel and freshwater supply, but also serves as an effective approach for co-production and efficiency enhancement. Evaporators with uranium adsorption capability tailored for natural aquatic environments are required to integrate robust mechanical stability with high-efficiency uranium extraction performance. To address this critical demand, a Janus hydrogel films was developed using a stable colloidal dispersion as the precursor. Polyvinyl alcohol was employed as the stabilizer, endowing the colloidal dispersion-prepared via emulsion polymerization-with long-term dispersibility. This characteristic is conducive to large-scale fabrication and storage during engineering applications. During the crosslinking-induced formation of the hydrogel film, adsorptive particles were in-situ immobilized, resulting in a hydrogel film with a highly dispersed adsorbent network featuring a large specific surface area. Under simulated sunlight illumination, the Janus hydrogel films achieved a uranium adsorption capacity of 14.5 mg/g and the evaporation rate of 2.62 kg·m⁻²·h⁻¹ in seawater, attributed to the synergistic effect of photothermal conversion and functional group-mediated adsorption. This material integrates multiple superior advantages including self-floating capability, excellent uranium extraction efficiency, stable mechanical performance, and high photothermal conversion efficiency, making it suitable for engineering applications in seawater uranium extraction and seawater desalination. This study provides a viable technical solution for the practical application of Janus-structured uranium adsorbents in natural aquatic environments.