Hollow Core–Shell Bismuth Based Al‐Doped Silica Materials for Powerful Co‐Sequestration of Radioactive I₂ and CH₃I

Abstract

Developing pure inorganic materials capable of efficiently co‐removing radioactive I2 and CH3I has always been a major challenge. Bismuth‐based materials (BBMs) have garnered considerable attention due to their impressive I2 sorption capacity at high‐temperature and cost‐effectiveness. However, solely relying on bismuth components falls short in effectively removing CH3I 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 Bi2O3 as a hard template and through simple alkaline‐etching and CTAB‐assisted surface coassembly methods (Bi@Al/SiO2) 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 I2 and CH3I for the first time, demonstrating remarkable sorption capacities of 533.1 and 421.5 mg g−1, 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 CH3I sorption. This innovative structural design of sorbent enables exceptional co‐removal capabilities for both I2 and CH3I. Furthermore, the core–shell structure enhances the retention of captured iodine within the sorbents, which may further prevent potential leakage.