Bi0-Reduced Graphene Oxide Composites for the Enhanced Capture and Cold Immobilization of Off-Gas Radioactive Iodine

Abstract

Radioactive waste management is critical for maintainingthe sustainabilityof nuclear fuel cycles. In this study, we propose a novel bismuth-basedreduced graphene oxide (Bi-0-rGO) composite for theimmobilization of off-gas radioactive iodine. This material synthesizedvia a solvothermal route exhibited a low surface area (2.96 m(2)/g) combined with a maximum iodine sorption capacity of 1228 & PLUSMN; 25 mg/g at 200 & DEG;C. The iodine sorbent was mixed with Bi2O3 powder and distilled water to fabricate wastematrices, which were cold-sintered at 300 & DEG;C under a uniaxialpressure of 500 MPa for 20 min to achieve a relative density of & SIM;98%and Vickers hardness of 1.3 & PLUSMN; 0.1 GPa. The utilized methodologyreduced the iodine leaching rate by approximately 3 orders of magnitudethrough the formation of a chemically durable iodine-bearing wasteform (BiOI). This study demonstrates the high potential of Bi-0-rGO as an innovative solution for the immobilizationof radioactive waste at relatively low temperatures.