Separation and purification of gadolinium, terbium and dysprosium by P204-P507 solvent impregnated resin in nitric acid system

Abstract

In recent years, the ¹⁶¹Tb nuclide has garnered increasing attention, particularly in the field of medical radiopharmaceuticals, due to its favorable characteristics, including a suitable half-life of 6.9 days, low-energy β particles (β_av = 154 keV), Auger electrons(≤40 keV), and accompanying gamma radiation. Additionally, it exhibits coordination properties and in vivo behavior akin to that of ¹⁷⁷Lu.This paper aims to investigate the separation and purification of the medical isotope ¹⁶¹Tb. The mixed solution containing Gd(III), Tb(III), and Dy(III) ions was used to simulate the solution of the irradiated target. The mass ratio of Gd(III), Tb(III), and Dy(III) was 1000: 1: 1. The static adsorption experiment was carried out by P204-P507 resin. The effects of initial solution acidity, solid–liquid ratio and contact time on the adsorption performance and the effect of desorption agent acidity on the desorption effect of Tb(III) were investigated. The experimental results show that P204-P507 has the best adsorption effect under 0.01 mol/L nitric acid. The adsorption capacity of Tb(III) can reach 156.44 μg/g when the solid–liquid ratio is 100 mg/mL and the adsorption time is 180 min. The desorption effect is the best when 1 mol/L nitric acid is used as the desorption agent of Tb(III). The resin was analyzed using characterization techniques such as SEM, FT-IR, and XPS. The adsorption kinetic data indicate that the pseudo-second-order kinetic model is more applicable, while the isothermal data correlate well with the Freundlich model. Finally, the complexation mechanism of the P204-P507 dual extractant with Tb was analyzed through theoretical calculations. The results show that each dimer forms an eight-membered ring with Tb(III), with a minimum adsorption energy of −0.383 Kcal/mol. The adsorption process is accompanied by charge transfer. Therefore, this study provides theoretical support and practical evidence for the effective separation of Gd(III), Tb(III), and Dy(III) using P204-P507 dual extractant impregnated resin.