Efficient removal and immobilization of radioactive iodide and iodate from aqueous solutions by bismuth-based composite beads

Effectively remove radioactive iodine from aqueous solutions is highly desirable for the purpose of radioactive liquid waste treatment. However, anionic radioiodine species do not prefer to sorb on minerals or inorganic sorbents. Herein, we report a stable millimeter-level bismuth-based polymer composite beads (δ-Bi2O3@PES) with fast removal kinetics and high adsorption capacities for both iodide (I−) and iodate (IO3−). Abundant micro-flower-like δ-Bi2O3 was embedded in the porous interconnection network of polymer composite beads, making it an effective adsorbent for removing radioactive iodine. δ-Bi2O3@PES composite beads showed high adsorption capacities of 95.4 mg/g and 170.6 mg/g for I− and IO3− by forming an insoluble Bi4I2O5 and BiOIO3 phase, respectively, which also can selectively remove iodine anions in the presence of large excesses of NO3– and SO42−. Furthermore, δ-Bi2O3@PES composite beads can highly reduce the Bi3+ leaching of δ-Bi2O3 powder after immersed in the acid solution and can be easily separated from the liquid after sorption. The performance of δ-Bi2O3@PES in dynamic column experiments indicates that economical Bi-based composite bead is a promising candidate sorbent for environmental remediation of actual iodine-contaminated water.