Ion-Exchange Adsorption of Cerium (III) Using AmberChrom 50WX2 Resin: Investigation of Mechanisms and Process Optimization.

Rare earth elements (REEs) are essential to modern technologies, yet their recovery from secondary sources remains a major challenge. This study investigated the adsorption of cerium (III), selected as a model REE, onto AmberChrom 50WX2, a commercial cation-exchange resin. Batch experiments evaluated the effects of resin dosage, solution pH, and initial concentration on adsorption performance, supported by kinetic, isotherm, and thermodynamic modeling. The Elovich model best fit the adsorption kinetics, consistent with reversible ion-exchange (specific ionic bonding) between Ce³⁺ and the resin sites, rather than irreversible chemisorption, while equilibrium data were consistent with the Langmuir isotherm, confirming monolayer adsorption on a homogeneous surface. Adsorption capacity increased with initial concentration but decreased per unit mass at higher resin dosages, as expected. Thermodynamic analysis revealed the process to be endothermic and increasingly spontaneous with temperature. AmberChrom 50WX2 exhibited stable performance over four adsorption–desorption cycles, demonstrating reusability, though it showed limited selectivity among trivalent REEs of similar ionic radii. These findings highlight the potential of AmberChrom 50WX2 for bulk REE recovery under acidic conditions typical of waste streams, providing a foundation for process development at larger scales.