Hollow Core-Shell Bismuth Based Al-Doped Silica Materials for Powerful Co-Sequestration of Radioactive I and CHI.

Developing pure inorganic materials capable of efficiently co-removing radioactive I and CHI has always been a major challenge. Bismuth-based materials (BBMs) have garnered considerable attention due to their impressive I sorption capacity at high-temperature and cost-effectiveness. However, solely relying on bismuth components falls short in effectively removing CHI and has not been systematically studied. Herein, a series of hollow mesoporous core-shell bifunctional materials with adjustable shell thickness and Si/Al ratio by using silica-coated BiO as a hard template and through simple alkaline-etching and CTAB-assisted surface coassembly methods (Bi@Al/SiO) is successfully synthesized. By meticulously controlling the thickness of the shell layer and precisely tuning of the Si/Al ratio composition, the synthesis of BBMs capable of co-removing radioactive I and CHI for the first time, demonstrating remarkable sorption capacities of 533.1 and 421.5 mg g, respectively is achieved. Both experimental and theoretical calculations indicate that the incorporation of acid sites within the shell layer is a key factor in achieving effective CHI sorption. This innovative structural design of sorbent enables exceptional co-removal capabilities for both I and CHI. Furthermore, the core-shell structure enhances the retention of captured iodine within the sorbents, which may further prevent potential leakage.