Flame-retardant porous hexagonal boron nitride for safe and effective radioactive iodine capture

Abstract

Appropriate disposal of radioactive iodine in spent nuclear fuel reprocessing represents an acknowledged challenging topic. Currently, most solid sorbents for radioactive iodine treatment are suffering from the risk of fire and explosion due to the presence of nitrogen oxides in the exhaust stream. Herein, we reported for the first time the use of porous hexagonal boron nitride (porous BN) to capture radioactive iodine and further studied its practicability and iodine-removal performance. A series of tests, such as flammability, acid leaching durability and so on, revealed the excellent thermal stability, acid-resistance, anti-oxidation activity and hydrophobic properties of porous BN. It should be highlighted that porous BN exhibits outstanding flame-retardant ability, which is superior to that of well-studied MOF and POP iodine-removal materials. These merits will enormously reduce the risk of fire and explosion in the exhaust stream and endow this material with great potential in practical radioactive waste reprocessing. Benefiting from the porous properties and Lewis acid–base interaction, porous BN demonstrated 213 wt% adsorption capacity for iodine vapor, which is a considerably high value among inorganic materials. The iodine removal performance of porous BN was further demonstrated by a column test under simulated reprocessing. Combining its superb physicochemical properties with iodine removal capacity, porous BN is thereby a promising iodine sorbent for safe and effective radioactive iodine capture in practical applications.