Bimetallic mutual-doping magnetic aerogels for iodine reduction capture and immobilization

Adsorption is considered to be one of the most effective methods to remove radioiodine from the solution. However, developing highly efficient adsorbents and the rapid recovery of the used adsorbents is still a challenge. Here, a series of Cu/Fe₃O₄ bimetallic mutual-doping magnetic aerogels (Cu/Fe₃O₄-BMMA) were synthesized. Based on the in-situ bimetallic co-gelation process, the high dispersion of Cu in the aerogel was realized, providing conditions for the efficient elimination of I₂. The Fe³⁺ in the initial gel was reduced to magnetic Fe₃O₄ during the preparation process, allowing for the quick recovery of the adsorbent through the application of a magnetic field. The adsorption experiments showed that Cu/Fe₃O₄-BMMA has good I₂ adsorption capacity (631.3 mg/g) and fast capture kinetics (equilibrium time < 30 min). In addition, Cu/Fe₃O₄-BMMA was able to effectively remove trace I₂ in the solution from ppm level (1.0 ppm) down to ppb level (≤30 ppb). The adsorbed I₂ was converted into stable CuI, avoiding secondary pollution due to desorption. Overall, this study provides a potentially efficient iodine capture material for long-term decay storage of radioactive iodine.