New Insight Into How Iron Oxide Minerals Influence Transport of Uranium in Subsurface
Iron-oxide minerals play a critical role in determining the mobility of subsurface contaminants such as uranium at DOE cleanup sites. Understanding how the surface reactivity of these minerals changes over time is critical to understanding uranium transport. Researchers funded by DOE and NSF at SLAC National Accelerator Laboratory and Stanford University have developed a new structural model that accounts for gaps in the mineral structure of ferrihydrite as it transforms to the more stable mineral hematite and shows that these gaps are likely to be important sites for the binding of contaminants such as uranium. Synchrotron-based studies led to a detailed analysis of the changes occurring in the mineral structure of ferrihydrite as it is converted to hematite. The research also produced new information about the interaction of microbes with these minerals and how these interactions influence the chemical form of uranium.
F. Marc Michel, Vidal Barrón, José Torrent, María P. Morales, Carlos J. Serna, Jean-François Boily, Qingsong Liu, Andrea Ambrosini, A. Cristina Cismasu, and Gordon E. Brown, Jr. “Ordered ferrimagnetic form of ferrihydrite reveals links among structure, composition, and magnetism,” Proceedings of the National Academy of Sciences, 107: 2787-2792 (2010).