Novel synthesis of Bi-Bi2O3-TiO2-C composite for capturing iodine-129 in off-gas

Abstract The Bi-Bi 2 O 3 -TiO 2 -C composites were prepared by a sol-gel method and investigated for capturing iodine-129 ( 129 I) in off-gas producing from spent fuel reprocessing. Firstly, the optimal process conditions were operated through the orthogonal experiments, showing that the capturing capacity of the optimal composite was calculated about 504.0 ± 19.5 mg/g, which is approximately 2.0-fold higher than that of the commercial silver-exchanged zeolites (AgX). Secondly, the structure and morphology of the Bi-Bi 2 O 3 -TiO 2 -C composite were characterized, suggesting that the Bi is regularly spherical in the shape, coating by the Bi 2 O 3 , TiO 2 and amorphous carbon. Finally, the mechanism for the iodine adsorption in the Bi-Bi 2 O 3 -TiO 2 -C system was revealed, demonstrating that the iodine was captured by physisorption and chemisorption.