Radioactive iodine is highly soluble in water, posing risks to public health and the environment. Existing materials for iodine treatment have disadvantages such as easy oxidation and aggregation of silver nanoparticles, limited adsorption capacity, and dependence on bulky instruments for detection, which hinders effective treatment of radioactive wastewater and rapid on-site monitoring.

In a study published in Separation and Purification Technology, researchers from Hefei Institutes of Physical Science of the Chinese Academy of Sciences developed a silver-decorated, metal-organic framework (MOF)-derived TiO_2-X nanocomposite enriched with oxygen vacancies, enabling both the removal and detection of trace radioactive iodide ions.

Researchers used a titanium-based MOF, MIL-125, as a precursor to construct a multifunctional Ag₂O-Ag@TiO_2-x (AT) nanocomposite. Through a controlled pyrolysis and solution deposition strategy, the material was engineered with dual active sites of Ag⁰ and Ag₂O. The resulting structure integrated oxygen vacancies with an Ag/TiO_2-x Schottky junction, forming a synergistic system that enabled iodide capture via a coupled photocatalytic oxidation and chemisorption mechanism.

Experimental results showed that the nanocomposite delivered effective iodine adsorption and maintained stable removal performance even at low iodide concentrations. The treated water met national surface water environmental standards. The material also exhibited iodoperoxidase-like activity, enabling a colorimetric sensing system based on AT/TMB/H₂O₂ for visual detection of iodide ions.

Moreover, the nanocomposite showed good resistance to interference from common anions and performed reliably in complex water environments, including seawater and nuclear wastewater. It showed good stability under irradiation. After exposure to γ-rays, it retained most of its adsorption performance, while the concentration of leached silver remained below national safety limits.

This study provides a practical approach for the removal and detection of radioactive iodine. It may support wastewater treatment in nuclear facilities and environmental remediation.