One of the main limitations radioiodine capture is the successful immobilization of the active iodine getter material in a low-porosity (dense) and high-iodine-loaded matrix. Iodine getters include metal-exchanged zeolites, metal-loaded silica-based scaffolds (e.g., aerogels, xerogels), or physisorption-based sorbents like metal-organic frameworks or other organic sorbents (e.g., activated carbon). This invention is based on using metallic bismuth metal to encapsulate the iodine-loaded sorbent into a ceramic-metal composite form where the metal is the bismuth and the ceramic is the metal-iodide (e.g., AgI, CuI, SnI4, BiI3, BiOI). After capturing iodine, the active sorbent, which could be something listed above or a pure metal getter like a metal wire, would be placed in a container with metallic Bi, melted and the metal iodides encapsulated in the Bi metal.