(400u) Recovery of Cerium (Ce) from Aqueous Solutions with Sugaring out Technology

The growing demand for rare earth elements (REEs) serves to emphasize the need for innovative, cost-effective, and sustainable extraction technologies. In this study, we explored a novel application of the sugaring-out extraction technique for the recovery of cerium (Ce) from aqueous solutions. Sugaring-out is a unique phase separation phenomenon caused by the addition of selected carbohydrate to water and organic solvent mixtures, providing a greener and energy-efficient alternative to conventional solvent extraction processes.

The extraction system consists of n-propanol and isopropanol as the organic solvents and glucose solution of varying concentration as the phase-separating agent. Cerium nitrate is used as the REE source. Key process parameters such as sugar concentration, temperature, pH and phase volume ratio were systematically investigated and optimized to maximize cerium extraction efficiency. Initial results demonstrated around 37% extraction efficiency from a 30mM Cerium (III) nitrate solution using 30% (w/w) glucose and 1:1 organic-to-aqueous phase ratio, highlighting the potential for further enhancement. Cerium partitioning between the phases was evaluated using ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy), providing insights into the underlying separation mechanism.

To the best of our knowledge, this is one of the first studies to explore sugaring out extraction technology for cerium recovery. Unlike conventional liquid-liquid extraction, this sugar-based aqueous two-phase system utilizes eco-friendly reagents under mild conditions. This method is simple and less toxic, making it a promising approach for REE recovery. By supporting clean energy and circular economy goals, this method offers sustainable alternative for REE recovery with reduced environmental impact and operational complexity.