RESEARCH ARTICLE

Selective capture of iodate anions by a cerium-based metal-organic framework

State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China

^* Corresponding author (email: shuaowang@suda.edu.cn)

Received: 24 January 2024
Revised: 19 March 2024
Accepted: 13 May 2024

Abstract

Effective remediation of radioactive IO₃⁻ is highly desirable for fuel reprocessing, medical waste disposal, and nuclear accidents. However, the nature of high solubility, strong mobility, and extremely hard to bind with minerals for IO₃⁻ makes this task an enormous challenge. Herein, a metal-organic framework material [Ce(IV)-MOF-808] with available Ce(IV) sites was used to efficiently remove IO₃⁻. Ce(IV)-MOF-808 exhibits superior selectivity and one of the highest adsorption capacities (623 mg·g⁻¹) for IO₃⁻ removal. Moreover, Ce(IV)-MOF-808 shows great adsorption performance for IO₃⁻ at low concentrations, and the distribution coefficient (K_d) value was calculated to be 2.60 × 10⁶ mL·g⁻¹. The exceptional IO₃⁻ uptake performance is attributed to the high affinity between Ce(IV) cluster and the oxyanion based on the comprehensive analysis of zeta potential and X-ray photoelectron spectroscopy (XPS) results, in which IO₃⁻ can easily replace the weakly coordinated ligand and form a strong coordination structure of Ce-O-I-O₂. More importantly, Ce(IV)-MOF-808 exhibits excellent uptake performance for IO₃⁻ from both the simulated Beishan groundwater system and Hanford groundwater system in the dynamic column separation test, indicating the highly promising practical application of Ce(IV)-MOF-808 in IO₃⁻ remediation from actual radioactive wastes.