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.

Synthesis and characterization of Ag@Cu-based MOFs as efficient adsorbents for iodine anions removal from aqueous solutions.

Due to the critical importance of capturing radioiodine from aquatic environments for human health and ecosystems, developing highly efficient adsorbent materials with rapid kinetics for capturing iodide ions in aqueous solutions is urgently needed. Although extensive research has been conducted on iodine adsorption in gas and organic phases, limited research has been dedicated to adsorption in aqueous solutions. An effective technique for removing iodide was proposed using Ag@Cu-based MOFs synthesized by incorporating Ag into calcined HKUST-1 with varying mass ratios of Ag/Cu-C. Extensive characterization using SEM, XRD, XPS, and nitrogen adsorption-desorption analysis confirmed successful incorporation of Ag in Cu-C. Batch adsorption experiments were conducted, demonstrating that the 5% Ag@Cu-C material exhibited a high adsorption capacity of 247.1 mg g-1 at pH 3. Mechanism investigations revealed that Cu0 and dissolved oxygen in water generate Cu2O and H2O2, while Ag and a small amount of CuO generate Ag2O and Cu2O. Furthermore, iodide ions in the solution are captured by Cu+ and Ag+ adsorption sites. These findings highlighted the potential of Ag@Cu-based MOFs as highly effective adsorbents for iodine anions removal in radioactive wastewater.