Research progress on the removal of iodine and fluoride by metal–organic frameworks

Metal-organic frameworks (MOFs) have emerged as versatile platforms for the efficient removal of iodide and fluoride contaminants (inorganic fluoride (F^-) and organic perfluorinated anions (PFAS)) from aqueous solutions, addressing critical environmental challenges associated with nuclear waste and groundwater pollution. This review highlights recent advances in MOF design strategies, including tailored metal nodes (e.g., Zr-, Ce-, Al-based), functionalized organic ligands (e.g., amino groups, N-rich linkers), and composite structures (e.g., MOF/carbon, MOF/polymer), which enhance adsorption capacity and selectivity. The removal mechanism of iodide typically involves electrostatic attraction, π-complexation, and redox interactions, among which the adsorption capacity of MOFs can reach 2500 mg g^-1; while for the removal of fluoride, it usually involves Lewis acid-base coordination, ligand exchange, and ion exchange. Here, the adsorption capacity of MOFs for fluoride ions exceeds 200 mg g^-1, and for perfluorooctanoic acid (PFOA), it reaches up to 3060 mg g^-1. Although the material has a good adsorption performance, it still faces challenges in terms of chemical stability, cycling stability and selectivity under harsh conditions. To address these issues, future research should prioritize low-cost, high-efficiency and sustainable synthesis to promote the practical application of water remediation. However, large-scale implementation remains constrained by techno-economic barriers.