Examining practical application feasibility of bismuth-embedded mesoporous silicon for effective removal of radioactive iodine

Granulation technology enables effective industrial use of powder adsorbents by addressing pressure drop and operability challenges in engineering systems. In this study, a bismuth-embedded mesoporous silicon‑iodine adsorbent (Bi/Bi 2 S 3 @SiO 2 ) was synthesized using oil-ammonia column granulation technology, enabling. This method enabled the efficient and controllable granulation of the powder adsorbent and large-scale production. Considering the high temperature, high humidity, NO x , and dynamic gas flow characteristics of spent fuel reprocessing exhaust gases, we systematically evaluated the dynamic iodine adsorption performance of the granular adsorbent under simulated real conditions. Experimental results indicate that the static adsorption capacity for iodine vapor of Bi/Bi 2 S 3 @SiO 2 –2 is approximately 600 mg/g. The optimized granular adsorbent exhibits excellent mechanical strength and a uniform particle size distribution. Although its static adsorption capacity decreases by approximately 10 %, the dynamic adsorption capacity reaches 112 mg/g after breakthrough. The iodine removal efficiency exceeds 99.00 % during a continuous 30 h test. Further mechanistic analysis reveals that the adsorption of iodine vapor by Bi/Bi 2 S 3 @SiO 2 –2 primarily occurs through stable chemical adsorption (BiI 3 ). This study provides essential data to support the advancement of controlled granulation technology and the engineering application of radioactive iodine adsorbents, presenting a new strategy for the design of adsorbents in nuclear waste treatment systems.