Interface-Engineered ZIF-8/CS Dual-Network Aerogels for Efficient Capture of Sr(II) Ions

Due to their poor resistance to swelling, developing biomass-based radionuclide-capturing aerogel adsorbents with high adsorption capacity and excellent mechanical stability remains a significant challenge. This paper describes a dual-network aerogel constructed using a multiscale interface-control strategy, leveraging Zn2+-induced chitosan precross-linking and entanglement of oxidized carboxymethyl cellulose (ox-CMC). Within this stable framework, ZIF-8 nanoparticles were synthesized in situ. This design, through physical entanglement and chemical cross-linking, suppressed the swelling of the dual-network framework. After 30 days of soaking, its tensile strength remained approximately 0.48 MPa, and it also exhibited good compressive resilience. Simultaneously, the nitrogen-rich channels of ZIF-8 synergize with the negatively charged surface of the dual network (zeta potential: −40.5 mV), resulting in an Sr2+ adsorption capacity of 226.8 mg/g, which is significantly higher than that of many clay- or polymer-based adsorbents. After 10 adsorption–desorption cycles, the aerogel retained 85.8% of its initial properties. This multiscale interface design provides a robust strategy for preparing swelling-resistant, high-performance biomass aerogels for advanced radioactive wastewater treatment.