Investigation of the Use of Ionic Liquid in the Separation of Some Rare Earth Elements (Ce and La) and Thorium from Aqueous Solutions by Liquid-Liquid Extraction Method
Project no. 20375 · Status: Kapanmış · 2019
Summary
In this project, experiments investigating the extraction conditions, stripping and extraction mechanisms were carried out for separation of cerium, lanthanum and thorium from nitrated aqueous solutions using liquid-liquid extraction method by Cyphos® IL 101 ionic liquid. The structure of the ionic liquid prepared was examined using FT-IR, HNMR and TGA. Extraction study was carried out for the simulated ore solution of Eskişehir-Beylikahır region using the data obtained. In studies with mixed solutions containing Th, Ce (III) and La, high extraction values were obtained for initial pH 2.15, initial concentration 50 ppm, time 15 minutes and 1:1 for ionic liquid/solution ratio. Th/Ce and Th/La separation factor ? values were found to be 1139 and 562, respectively, and the maximum extraction capacity for Th was 366.91 mg/L. In the stripping experiments, It was observed that 0.03 M EDTA solution containing 0.5 M NaCl performed 100% stripping for Th at 60 °C temperature and 60 min conditions. Extraction temperature and NO3-effect experiments performed with only Th-containing solutions showed that temperature and increasing nitrate concentration increased Th extraction. In the experiments conducted with Ce+4 to observe the effect of the value of the metal on the extraction, the highest efficiencies were obtained with 95.8% at the initial pH 5 and, 94% at 200 ppm in the initial concentration. In the mechanism explanation studies, It was observed that Cl- anion concentration increased with the initial concentration of metal, but the element p, which represents the cation group of the ionic liquid, did not change. An anion exchange mechanism in which thorium hydroxide complexes exchange with the Cl- anions has been proposed. In the extraction study for the ore simulated solution, 40% extraction efficiency is obtained for Th, while low efficiencies are obtained for other lanthanides.