Rare earth elements are composed of the fifteen lanthanide elements plus scandium and yttrium. These elements are considered energy-critical elements, whose shortage could significantly inhibit large-scale deployment of energy-related technologies that have the potential of transforming the production, transmission, storage, and conservation of energy, such as photovoltaic solar cells, wind turbines, and hybrid automobiles. Geothermal waters are potentially significant sources of rare earth elements; however, utilization of geothermal fluids for electricity generation seldom focuses on the recovery of rare earth elements. In this research project, a novel electrochemical membrane process, electrodialysis metathesis, will be investigated for the first time to separate and recover high purity rare earth elements from geothermal waters with minimal consumption of chemicals.
The goal of this 18-month project is to advance the fundamental knowledge of recovery of rare earth elements from geothermal waters using electrodialysis metathesis process. The research objectives are to determine: 1) the metathesis reactions and selectivity of rare earth elements in the electrodialysis metathesis process, and, 2) the mass transport mechanisms and kinetic of rare earth elements in the electrodialysis metathesis process. Metathesis, or double decomposition, reaction of ions passing through alternating ion-exchange membranes and applied current has been applied to separate ions commonly found in brackish water (i.e. calcium, sodium, magnesium, potassium, sulfate and chloride), but has not yet been applied to concentrate and recover rare earth elements. The intellectual merit of this research project is to study, for the first time, the possibility of applying electrodialysis metathesis to concentrate and extract rare earth elements from geothermal fluids, particularly from geothermal wells and power plant brines. This will contribute to save rare earth elements resources which are considered energy-critical elements and will also protect the environment. If successful, the development of this process will provide an alternative source of rare earth elements in the US. The long-term education goal is to train future generations of Hispanic STEM researchers on cutting-edge technologies for rare earth elements and minerals recovery and reuse. The educational objectives are to: 1) provide STEM students advanced skills on membrane process, and, 2) promote STEM knowledge and engineering literary enrichment about energy-strategic materials on K-12 Hispanic students. The PI will create a membrane separation laboratory research module on minerals and energy-critical elements for the undergraduate and graduate Environmental Engineering laboratory classes. They will also create an interactive tool on energy-critical elements for K-12 Hispanic students.
