Adsorption and selective properties of carbonate and phosphate sorbents in three-component Cs⁺, Sr²⁺, Co²⁺-containing solutions

This paper presents the results of a study on the purification of three-component solutions containing Cs+, Sr2+, and Co2+ ions using carbonate and phosphate sorbents obtained from natural dolomite by thermal activation at 800 °C (D-800), phosphating (PD), and phosphating followed by modification with zirconyl salts (PD-Zr). The selectivity and efficiency of sorbents in a three-component solution were studied, including sequential application in multiple stages. It was found that the synthesized sorbents exhibit varying selectivity for Cs+, Sr2+, and Co2+ ions. Carbonate and phosphate sorbents D-800 and PD selectively sorb divalent metal ions Sr2+ and Co2+ in a three-component mixture. PD-Zr exhibits no selectivity for any of the ions. The sorption efficiency for the studied ions is as follows: for D-800: Co > Sr, for PD: Co > Sr » Cs, and for PD-Zr: Co > Sr > Cs. It was found that the most effective purification of a three-component solution (recovery rate of ~98‒100 %) is achieved by combining carbonate and phosphate sorbents at different purification stages. After a combined three-stage purification of the solution, residual concentrations of Co2+ ions are below the detection limit, while those of Sr2+ and Cs+ ions are 0.02 and 0.31 mg/L, respectively.

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