Features of extraction of neodymium ions by interpolymer systems based on salt forms of industrial ionites

Abstract

This research aimed to study the effect of remote interaction and mutual activation between salt forms of AB-17-8(Cl^-) and KU-2-8(Na⁺) ion exchange resins on the sorption of neodymium ions. The concentration of neodymium ions was determined using a spectrophotometer based on the interaction with the colored arsenazo (III) reagent. The degree of extraction of neodymium ions during sorption and the degree of extraction of this metal during desorption from the polymer matrix was calculated. The influence of the choice of sorption mode on the efficiency of neodymium extraction is studied: dynamic (with mixing of the solution from which the metal was extracted) and static (without mixing). Based on the obtained dynamics of processes, it is established that when mixing the solution (the range of mixing speed is 40-80 rpm) the equilibrium between sorption and desorption of the metal is established after 6 hours of interaction. Also, in the dynamic mode, the target metal was sorbed much better than in the static mode, affecting the amount of metal ions obtained during desorption. It was found that the maximum degree of neodymium ion sorption in the interpolymer system is observed at a 5:1 hydrogel ratio and 48 hours of remote interaction without mixing. It is 42.8 mg/l of the residual concentration. In the dynamic mode, the maximum sorption is observed for the initial cationite, with a residual concentration of 8.28 mg/l. When calculated per 1 mol of cationite, the effect of mutual activation of hydrogels is visible, which is proved by the tendency to increase the degree of neodymium sorption from the ratio of 6:0 (the initial cationite) to 1:5.  A significant increase in the sorption of neodymium ions is observed in various molar ratios of ionites. These results indicate the appearance of ionized structures that form conformations that provide optimal conditions for the sorption of neodymium ions from an aqueous solution of its salt, which can serve practical purposes for its selective extraction from industrial mixtures. The necessity of metal extraction by hydrogels in dynamic mode is established for faster operation of industrial plants and more complete metal binding by polymer matrices.