In-situ growth of zeolitic imidazolate framework-8 on polypyrrole nanotubes for highly efficient and reversible capture of radioiodine

Effective capture of radioiodine derived from nuclear reactor accidents and spent fuel reprocessing is of critical significance for the sustainable development of nuclear energy. Herein, we reported the successful synthesis of core-shell PPyNT@ZIF-8 (PZ) nanocomposites with ZIF-8 nanocrystals decorating polypyrrole nanotubes (PPyNT) through a facile, self-assembly procedure. Taking advantage of abundant electron-rich nitrogen atoms of polypyrrole skeleton as well as the high specific surface areas and porosities, these PZ nanocomposites had potential application in radioiodine capture. The maximum uptake capacity of as-synthesized PZ nanocomposites for vapor iodine reached up to 603.8 wt% within 5 h. Additionally, PZ nanocomposites exhibited excellent recycle abilities, as the uptake capacity of PZ-3 still remained 381.7 wt% (63.2% of the initial capacity) after five capture-release cycles. In iodine/cyclohexane solution, the maximum iodine adsorption capacity was 837.9 mg g-1 and all of the loaded iodine could be effectively released in ethanol solution. The excellent iodine capture performance was primarily attributed to the strong affinity between the Lewis acidic iodine molecules and the Lewis basic nitrogen atoms to form polyiodide ions. Considering their excellent iodine adsorption capacity and superior stability, PZ nanocomposites could be employed to effectively eliminate radioactive iodine.