Redox Cycling Driven Transformation of Manganese Oxide Minerals

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With support from the Environmental Chemical Sciences (ECS) Program of the Chemistry Division, Yuanzhi Tang and Hailong Chen of the Georgia Institute of Technology will investigate the impact of repeated oxidation-reduction reactions on the structure of manganese (Mn) oxides. The studies will utilize the tools of X-ray diffraction to elucidate key details associated with the change in morphology, molecular structure and properties of manganese oxides when subjected to these oxidation/reduction cycles. The project includes developing high school curriculum materials that integrate environmental, chemical, and materials concepts. It will promote the training of the next generation of scientists at the chemistry/geoscience interface and do so with an emphasis on increasing the participation of team members from underrepresented groups in science. Drs. Tang and Chen will incorporate the research results into undergraduate and graduate teaching on environmental and materials sciences. The research team will develop community outreach activities to showcase mineral and mineral properties to the general public at the annual Atlanta Science Festival.Manganese oxides exist in nearly all environmental settings. They have significant influence on the biogeochemical cycling of many important metals, nutrients, organic compounds, and contaminants. In natural environments and over long time scales, these minerals commonly experience many cycles of oxidation and reduction. Still, much remains unknown about the influence of such cyclic oxidation-reduction cycles on the structure and transformation of Mn oxides. It is important to fill this knowledge gap needs in order to develop better predictive models for understanding the fate of contaminants and nutrients in the natural environment. This project will systematically examine the structural transformation of Mn oxides during cyclic oxidation-reduction reactions. The research team will use electrochemical methods to control the rate and magnitude of electron flow. They will utilize synchrotron-based X-ray characterization to investigate the kinetics, mechanisms, and reaction pathways associated with these redox cycles.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.