Noncovalently Functionalized COF-Derived Carbon with Open Fibrous Network for Efficient Separation of Medical Lanthanides

Medical lanthanides, such as Dy and Ho, which are usually obtained through nuclear reactions and rapid decays of adjacent elements, play an increasingly important role in tumor diagnosis and treatment. However, due to the nearly identical physical and chemical properties, as well as the low proportions and strict purification requirements of medical lanthanide radionuclides, the separation of these adjacent lanthanides from each other is a huge challenge. Herein, we successfully developed a class of noncovalently functionalized carbon with an open fibrous network derived from covalent organic frameworks (COFs) for the rapid and efficient separation of medical lanthanides through extraction chromatography. The open network facilitated rapid fluid flow, while the thorny surface further increased the effective accessible area. The carbonaceous structural frameworks also endowed the materials with excellent stabilities, enabling them to effectively withstand the high acidity (1 M HNO₃) during the separation process. Impressively, for the separation of medical lanthanide ions Dy³⁺/Ho³⁺, the prepared carbon fibers demonstrated a recovery rate of up to 98.6% and a decontamination coefficient (quantitative indicators for measuring the degree of pollutant removal during radioactive decontamination) of 98.6 for holmium. Moreover, the separation system also has the advantages of fast fluid flow (0.17 mL/min), small elution volume (6 mL), and excellent cycling performance (>4 times), which can also be applied to the effective separation of other lanthanide ions. This study provides new ideas and approaches for the derivatization of COFs and the resolution of bottleneck problems in the separation of adjacent lanthanide elements.