Anthropogenic activities, such as uranium mining and the production of nuclear energy and nuclear weapons, have led to significant uranium contamination of the environment, leaving populations vulnerable to negative health effects. In order to effectively remediate uranium contamination, the mobility of uranium in the environment and its natural attenuation through sorption with active mineral phases, needs to be studied in depth first. This study aims to determine how U(VI) mobility is affected by manganese oxides in the presence and absence of siderophore Desferrioxamine-B (DFOB). Experiments focused on two common manganese minerals, pyrolusite (ß-MnO2) and manganite (γ-MnOOH). Adsorption experiments with U(VI)-DFOB were performed with pyrolusite at pH 3.5, 6, 8. Control adsorption experiments were also performed with U(VI) and DFOB in order to elucidate the role each component plays in the sorption process. The concentrations ranged from 6 µM to 78µM. For manganite, adsorption experiments were performed at pH 6 and 8 with U(VI)-DFOB and with controls of U(VI) and DFOB and a comparison was drawn with the corresponding values from pyrolusite. For pyrolusite, the presence of DFOB largely increased the U(VI) adsorption for all pH values. U(VI) adsorption increased as pH increased due to DFOB electrostatically adsorbing to pyrolusite while complexed to U(VI). In addition, DFOB also adsorbed separately from U(VI) leading to hydrolysis and degradation of the molecule that promoted dissolution of the mineral. For manganite, U(VI) showed high adsorption levels in the control experiment, and these rates were unchanged when DFOB was added, leading to the conclusion that DFOB does not affect U(VI) interaction with that substrate. Also, DFOB showed lower adsorption and smaller amounts of hydrolysis with manganite when compared to pyrolusite.
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Master of Science (M.S.)
College of Sciences
Length of Campus-only Access
Masters Thesis (Open Access)
Snyder, Morgan, "Sorption of U(VI) onto Manganese Oxides in the Presence of Siderophore Desferrioxamine-B" (2020). Electronic Theses and Dissertations, 2020-. 815.