ChBE Fall Seminar: Molecular Scale Understanding of Rare Earth Separations

The Department of Chemical and Biological Engineering welcomes Ahmet Uysal, a group leader for separation science group of the Chemical Sciences and Engineering Division at Argonne National Laboratory, for a lecture titled “Molecular Scale Understanding of Rare Earth Separations” on Wednesday, November 2, 2022, from 3:15–4:30 p.m. in Room 108 of Perlstein Hall. 


Chemical separations are central to our energy, environment, and security needs. Ten to 15 percent of all the energy consumption in the world is due to separation processes. The increasing demand in electronic display, battery, and magnet technologies require better refinery and recycling processes for rare earths and other critical materials. The contaminated underground waters from nuclear waste leaks still wait to be cleaned. Our group address these challenges by studying molecular-scale structures and energy drivers in heavy element separations. My talk will summarize two of our projects. Liquid-liquid extraction (LLE) is one of the go-to methods in heavy element separations. In LLE, metal ions are transferred from an aqueous phase into an organic phase with the help of amphiphilic extractant molecules. The aqueous phase speciation, interfacial interactions, and the organic phase structures create a complex free-energy landscape that require a detailed investigation. Ahmet Uysal will give examples from rare earth separations to demonstrate our approach. The group uses small angle X-ray scattering to investigate the complex fluids formed after the extraction. It pays special attention to interfaces. It combines multiple surface sensitive techniques to investigate extractant-metal interactions and interfacial water structures. Uysal will emphasize the connections and correlations between the interfacial structures and the nanoscale organic phase structures. Graphene-based membrane and sorbent materials have been extensively studied in recent years, due to their mechanical stability, unique structural and functional properties, tunability, and high surface area. Graphene-based materials, alone or as additives, can be very useful under harsh conditions of heavy element separations, where the stability of polymer based materials fail. In spite of their popularity, molecular scale details of ion adsorption at graphene and graphene oxide interfaces are poorly understood. Especially, understanding the interplay between the ion hydration and adsorption is very challenging at these interfaces. We utilize in situ synchrotron X-ray scattering and vibrational sum frequency generation (VSFG) spectroscopy techniques to study trivalent ion adsorption at graphene and graphene oxide surfaces. Our initial studies focus on the two end points of the broad graphene-based materials spectrum. High-quality pristine graphene and graphene oxide.


Ahmet Uysal is a group leader for separation science group of the Chemical Sciences and Engineering Division at Argonne National Laboratory. His current research focuses on chemical separation of heavy elements, metal-amphiphile interactions at aqueous interfaces, and ion adsorption on graphene based material surfaces. He specializes in surface specific synchrotron X-ray scattering and vibrational sum frequency generation spectroscopy. He received his M.S. and Ph.D. in physics from the University of Pittsburgh and Northwestern University, respectively. Before joining separation science group, he was a postdoctoral appointee at Interfacial Processes Group at Argonne. Uysal received Department of Energy Early Career Award in 2019.