Adsorption of lanthanum and cerium on chelating ion exchange resins: kinetic and thermodynamic studies

As the demand for rare earth elements (REE) increases in the coming years, techniques to obtain these elements from different sources may be explored. A hydrometallurgical route may achieve the sustainable approaches signed by countries. For this, separation techniques need to be explored, and chelating ion exchange resins are the most prominent. For this reason, to enhance the possibilities for REE separation, the main focus of this work was to study kinetics models and the thermodynamics of lanthanum and cerium adsorption at laboratory scale under industrially operating conditions. Three different functional groups were evaluated through the chelating resins M4195, TP207, and XUS43605. The effect of pH and resin dosage were evaluated, as well as the kinetic models (pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion) and thermodynamic parameters. The results presented here could be used for industrial applications. Pseudo-second order provided a better fit for both M4195 and TP207, and the intraparticle diffusion fitted better for XUS43605. Thermodynamic experiments have shown that the adsorption of lanthanum and cerium are spontaneous and endothermic. These findings represent the novelty of the present study since it could be used in selective separation of lanthanum and cerium onto chelating resins from primary and secondary sources.