A Preliminary Sorption Study of Uranium on MnO2 (Pyrolusite) in the Presence of Siderophore Desferrioxamine B—The Mechanism of a Ternary System

Abstract

Manganese oxides have influential sorptive properties to efficiently sequester metals, such as uranium. Sorption can become complicated by metal chelating siderophores, which create a ternary system that is capable of multiple feasible mechanisms. This study analyzes the sorption behavior of desferrioxamine B (DFOB) and desferrioxamine D (DFOD) onto pyrolusite, β-MnO2, in the presence of U(VI) at pHs 6 and 8. The electrostatic adsorption performance is shown to have a 23% difference between the DFOB and DFOD surface sorption at pH 6. Inner-sphere coordination was identified through hydrolysis products of succinate and acetate. Together, these behaviors indicate a ternary complex system where both metals and ligands interact with the surface. Therefore, uranium in the environment can be attenuated by the conditions of a complex configuration involving multiple species and functional groups. This mechanism needs to be considered for any future modeling or strategies involving radionuclide remediation.