Novel synthesis of NaY-NH4F-Bi2S3 composite for enhancing iodine capture

Effective capture of radioactive iodine in spent fuel reprocessing is an urgent problem to be solved. In this study, we reported a novel fluoride modified bismuth sulfide supported NaY zeolite material (NaY-NH₄F-Bi₂S₃), prepared by hydrothermal method. The zeolite with a hydrophobic skeleton was obtained by etching with NH₄F solution. The adsorption mechanism generally follows preferential iodine enrichment in NaY zeolite microporous channels and is subsequently immobilized by loaded bismuth sulfide sites on NaY zeolite. Under the combination of physical and chemosorption, the sorption capacity of NaY-NH₄F-Bi₂S₃ reaches 491 mg/g, which is much higher than that of bare NaY zeolite. The excellent thermal stability and radiation stability greatly enhance its iodine capture performance under harsh conditions. The comprehensive characteristics of high cost-effectiveness, low toxicity, good radiation resistance, and good thermal stability make it have potential applications in the capture, immobilization and storage of radioactive gaseous iodine during spent fuel reprocessing.