Innovative Extraction of Rare Earth Elements using Cloud Point Extraction with Nano-Ions

This Master’s 2 internship will be carried out at the L2IA Laboratory of the ICSM, under the supervision of experts in the fields of nano-ions, metal ion speciation in solution, and liquid-liquid extraction.

Rare earth elements (REEs) are critical components in the production of permanent magnets, which are indispensable for electric vehicles and wind turbines. However, their mutual separation remains a major challenge due to their highly similar physicochemical properties. Cloud Point Extraction (CPE) has emerged as a promising and environmentally friendly alternative to conventional solvent extraction techniques for REE separation. In CPE, metal species are extracted without the use of toxic organic solvents, relying instead on a complexing agent and a thermosensitive nonionic surfactant. This approach enables phase separation under well-defined concentration a

Recent studies have demonstrated that certain nano-ions, such as polyoxometalates (POMs), exhibit super-chaotropic properties, enabling strong interactions with hydrated organic species such as micelles formed by nonionic surfactants (M. Hohenschutz et al., P. Angew. Chemie Internat. Ed. 59, 8084 (2020)). The presence of these multicharged nano-anions at the micellar surface suggests a high adsorption capacity for rare earth cations, offering a promising pathway toward more efficient, selective, and environmentally sustainable separation processes.

This Master 2 internship aims to investigate the selective extraction of trivalent rare earth ions using Cloud Point Extraction in the presence of other cations in aqueous solution. The extraction will be performed using super-chaotropic nano-ions and low-toxicity, biodegradable nonionic surfactants. The main objective is to identify an efficient extraction system with a cloud point below 50 °C, thereby reducing the energy required for phase separation.

• Determining the cloud point temperature and extraction efficiency (via ICP, X-ray fluorescence, SAXS);
• Varying the nature and concentration of surfactants, POMs, and metal cations in solution;
• Measuring the physicochemical properties of the solutions (acidity, density, water activity);
• Determining the molecular speciation of the phases using complementary spectroscopic techniques (UV-Vis, IR, NMR).

• Master’s student (M2) in physical chemistry
• Strong interest in solution chemistry, colloidal systems, and spectroscopy