Features of Selective Sorption of Neodymium and Praseodymium Ions by Interpolymer Systems Based on Industrial Sorbents KU-2-8 and AV-17-8

In this study, the possibilities of selective sorption of neodymium and praseodymium ions from a mixture of their solution using interpolymer systems composed of two industrial sorbents, cation exchangers KU-2-8 (Na⁺) and AB-17-8 (Cl^-), at different molar ratios were investigated. The processes of sorption and desorption were carried out in two modes: dynamic (with active stirring) and static (without stirring the working solution from which REEs were extracted). According to the obtained results, sorption in the dynamic mode in the ratios of 4:2 and 3:3 does not lead to any selectivity. However, a high degree of extraction was noted for both ions: Pr³⁺ = 99.36%, Nd³⁺ = 95.67% for the 4:2 system and Pr³⁺ = 81.33%, Nd³⁺ = 79% for the 3:3 system. In the static mode, the degree of extraction of both metals was significantly lower: for the 4:2 system Pr³⁺ = 19.33%, Nd³⁺ = 24%, but greater selectivity with respect to neodymium was observed. With a ratio of 4:2, neodymium was sorbed better than praseodymium by 24.16%, and in the 3:3 system by 39.83%. When desorption from the cationite was carried out with nitric acid, a similar tendency was preserved. Thus, it was shown that interpolymer systems can be used in industry by varying the conditions of sorption and desorption for the successful extraction of neodymium and praseodymium from industrial solutions.