Sulfur vacancy-rich bismuth sulfide nanowire derived from CAU-17 for radioactive iodine capture in complex environments: Performance and intrinsic mechanisms
Kai-Wei Chen, Xinyu Zhou, Xiaojun Dai, Yi‐Ting Chen, Shuxuan Li, Chunhui Gong, Peng Wang, Ping Mao, Yan Jiao, Kai Chen, Yi Yang
Abstract
Effective capture and immobilization of volatile radioiodine from the off-gas of post-treatment plants is crucial for nuclear safety and public health, considering its long half-life, high toxicity, and environmental mobility. Herein, sulfur vacancy-rich Vs-Bi 2 S 3 @C nanocomposites were systematically synthesized via a one-step solvothermal vulcanization of CAU-17 precursor. Batch adsorption experiments demonstrated that the as-synthesized materials exhibited superior iodine adsorption capacity (1505.8 mg g −1 at 200 °C), fast equilibrium time (60 min), and high chemisorption ratio (91.7%), which might benefit from the nanowire structure and abundant sulfur vacancies of Bi 2 S 3 . Furthermore, Vs-Bi 2 S 3 @C composites exhibited excellent iodine capture performance in complex environments (high temperatures, high humidity and radiation exposure). Mechanistic investigations revealed that the I 2 capture by fabricated materials primarily involved the chemical adsorption between Bi 2 S 3 and I 2 to form BiI 3 , and the interaction of I 2 with electrons provided by sulfur vacancies to form polyiodide anions (I 3 - ). The post-adsorbed iodine samples were successfully immobilized into commercial glass fractions in a stable form (Bi x O y I), exhibiting a normalized iodine leaching rate of 3.81 × 10 −5 g m −2 d −1 . Overall, our work offers a novel strategy for the design of adsorbent materials tailed for efficient capture and immobilization of volatile radioiodine.