Rapid and selective removal of radioactive iodide ions from wastewater via bismuth-based metal-organic frameworks

As one of the main components of the nuclear wastewater discharged from Fukushima, the efficient and safe disposal of radioactive 129I- is very urgent. Here, the trapping ability of water-soluble iodine anions is studied through a metal-organic framework of bismuth (Bi-MOF, select CAU-17 as the representative). It is found that CAU-17 achieves efficient capture of I- ions through chemical and physical cooperative adsorption, with a maximum adsorption capacity of up to 268.9 mg g-1. In addition, the adsorbent also exhibits superior adsorption kinetics and selectivity for I- ions and works stably over a wide pH range of 2–12. Density functional theory (DFT) calculations indicate that most I- ions are immobilized by attacking the Bi3+ sites of the CAU-17 ternary channel to form BiOI compounds. Compared with silver-based adsorbent, the prepared Bi-based adsorbent CAU-17 is more economical and practical. In summary, this work demonstrates the promising application of Bi-MOFs for purifying industrial water-soluble radioactive iodide ions.