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

The Bi-Bi2O3-TiO2-C composites were prepared by a sol-gel method and investigated for capturing iodine-129 (1291) 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-Bi2O3-TiO2-C composite were characterized, suggesting that the Bi is regularly spherical in the shape, coating by the Bi2O3, TiO2 and amorphous carbon. Finally, the mechanism for the iodine adsorption in the Bi-Bi2O3-TiO2-C system was revealed, demonstrating that the iodine was captured by physisorption and chemisorption.