The study of cerium separation from aqueous solutions using Dowex 50WX8 resin via ion exchange in batch and continuous mode.

Abstract

The solutions obtained from rare earth element (REE) processing are often acidic. The low pH is a challenge in the separation of REE. Hence, this study focuses on separating Ce(III) from acidic solutions by the ion exchange method using Dowex 50W-X8 resin. In the batch system, the maximum of Ce(III) exchange occurred at a resin dosage of 0.16 g, temperature of 35 °C, and sulfuric acid concentration of 0.2 M. The Ce(III) exchange process achieved equilibrium in 6 h with a capacity of 10.34 mg g^-1, and the kinetic behavior was best fitted with the pseudo-second-order model (R² = 0.999). The Langmuir model was followed among the isotherm models, which showed that adsorption occurred in the monolayer. The thermodynamic study revealed that the process was endothermic and spontaneous. In the continuous system, the Ce(III) exchange was carried out for 26 h, and the breakthrough curve obtained was the best fit with the Thomas kinetic model (R² = 0.963). Resin regeneration was performed by passing a 3 M sulfuric acid solution through a fixed bed column, resulting in 98.81% desorption. Finally, to understand the Ce(III) exchange behavior in a real medium, the process was investigated in a simulated solution containing Th(IV) and Fe(II) ions.