Construction of nano-rubber toughened double-network hydrogels and the efficient adsorption performance and mechanism for uranyl ions

In this study, an innovative synergistic strategy combining radiation-induced graft polymerization and the cyanohydroxylamine method was employed to successfully construct a polyacrylamide/polybutadiene/polyacrylonitrile-amidoxime (PAM/PB/PAO) double-network (DN) hydrogel toughened by nano-polybutadiene rubber. Leveraging the DN topological design and rubber nano-phase reinforcement, this material exhibits exceptional fatigue performance (with a compressive stress retention rate of >90 % after 30 cycles of 80 % strain) and a high uranium adsorption capacity of 763.40 mg g −1 . In solutions containing seven competing ions, its distribution coefficient reaches 13,750.90 mL g −1 , and the adsorption efficiency remains above 91.10 % after 4 adsorption cycles. Density Functional Theory (DFT) calculations reveal that the amidoxime group serves as the primary adsorption site, which can form a multi-dentate chelating structure with the amide group. Additionally, the Intrinsic Bond Strength Index-Molecular Hamiltonian (IGMH) and Electron Density Analysis-Natural Orbital for Chemical Valence (EDA-NOCV) analyses further confirm the electrostatically dominated interaction mechanism. This research provides a novel insight into the design of high-strength and tough adsorbent materials, demonstrating promising application prospects in the field of uranium recovery from nuclear wastewater.