Tailoring Phosphonic Acid-Functionalized Nanofibers via Facile Fabrication for Enhanced Yb(III)/Lu(III) Selective Separation

Achieving efficient separation of ytterbium (Yb) and lutetium (Lu) is of great significance for the production of medical isotope lutetium-177 (¹⁷⁷Lu). In this work, phosphonic acid-functionalized polyacrylonitrile nanofibers (PPA-PAN-NFs) were successfully prepared by combining electrospinning and postmodification, as verified by comprehensive characterization techniques (e.g., SEM, BET, CA, FT-IR, and XPS). The PPA-PAN-NFs demonstrated favorable adsorption capacities for Yb(III) and Lu(III), 52.17 mg/g and 66.45 mg/g, respectively, which surpass the capacities of most materials reported in the literature. XPS analysis revealed that the adsorption mechanism involves coordination of lanthanide ions with the oxygen atoms of phosphonic acid groups and the nitrogen atoms of amine groups. Differences in coordination affinity induced by lanthanide contraction serve as key drivers for the efficient separation of these ions. The feasibility and selectivity of PPA-PAN-NFs for the separation of Yb (III) and Lu (III) have been evaluated by means of dynamic column separation. Effective separation can be realized when the chromatography column has a height of 3.0 cm and a diameter of 1.6 cm, with 1.5 g of PPA-PAN-NFs loaded and 0.1 mol/L HNO₃ used as the eluant. The recovery rate of Lu(III) reached 82%, with a separation factor of 14.91 for Yb(III)/Lu(III), indicating high selectivity in the separation process. This study applies nanofiber materials to medical radionuclide separation. It provides an alternative approach for ¹⁷⁷Lu separation and is also valuable for the development of nanofiber-based methods in radionuclide separation.