Synergistic effects of lattice incorporation and spatial confinement for radionuclides immobilization in sodalite derived from 4A zeolite.

The efficient immobilization of radionuclides such as Cs, Sr, Ba, and Ce remains a critical challenge in the safe treatment of radioactive waste salts. Here we report a synergistic lattice incorporation and spatial confinement strategy that enables one-step immobilization of multiple radionuclides within a sodalite framework derived from topotactic transformation of 4 A zeolite. Mechanical blending followed by solid-state sintering at 850℃ for 2 h produces a dense sodalite solidified matrix exhibiting exceptional thermal stability, radiation resistance, acid-alkali tolerance and mechanical integrity. The normalized leaching rates of Cs, Sr, Ba, and Ce were all below 5 × 10-5g/(cm2·d) after 28 days. Multiscale characterization combined with density functional theory (DFT) reveals that chemical adsorption, ion exchange, lattice incorporation, and covalent coordination collectively stabilize radionuclides through coupled spatial confinement and lattice immobilization. A prospective life cycle assessment (LCA) confirms that this sodalite operates with markedly reduced carbon emissions and energy demand compared to conventional vitrification and ceramic process. These findings provide a promising low-energy, high-safety pathway for the immobilization and disposal of irradiated nuclear fuels.