Photochemical Synthesis of Hierarchical Adsorbents for Gaseous Iodine Capture and Storage

Abstract

Developing rapid, green synthesis strategies for adsorbent preparation through preparative chemistry, and elucidating pore and metal adsorption mechanisms, represent essential goals in achieving highly efficient capture and storage of radioactive iodine in the nuclear industry. This work utilizes solvent-free photopolymerization and one-step photoreduction methods to synthesize hierarchical zeolite MS-1 and copper-modified zeolite Cu@MS-1, respectively. Focusing on the effects of metal species and pore structure on adsorption performance and mechanisms, their application to radioactive iodine sequestration from spent fuel is evaluated. The findings show adsorption of gaseous iodine by hierarchical zeolite MS-1 is predominantly physical. At 75°C, it rapidly reaches high equilibrium adsorption capacity (524 mg/g) within 40 minutes, with faster iodine uptake kinetics than fully microporous zeolites and higher capacity than fully mesoporous silica. Introduction of metallic copper contributes additional chemical adsorption, efficaciously enhancing the MS-1 affinity for gaseous iodine. Cu@MS-1 achieves considerable equilibrium adsorption capacity (520 mg/g) in only 30 minutes, and improved radioactive iodine retention. The photochemical synthesis approach generates no liquid waste and forms the zeolite framework in 10 minutes. The obtained hierarchical zeolites MS-1 and Cu@MS-1 have high gaseous iodine capture and storage abilities, opening a new route for rapid green synthesis of highly efficient radioactive iodine adsorbents.

Keywords: Hierarchical zeolite, Photochemical Synthesis, Iodine capture and storage