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Updated: Aug 18, 2026
Manganese Oxide Nanoparticle Synthesis by Thermal Decomposition of Manganese(II) Acetylacetonate
Published on: June 18, 2020
Interfacial interactions between Np(V) and manganese oxide minerals manganite and hausmannite
P A Wilk1, D A Shaughnessy, R E Wilson
1Chemical Biology and Nuclear Science Division, Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
Abstract:
Manganese oxides, present as minor phases in the vadose zone, have been previously shown to sequester large quantities of plutonium under environmental conditions. We are now continuing these studies with Np(V). Sorption onto manganite (MnOOH) and hausmannite (Mn3O4) at solid-to-solution ratios of 2.5-3.3 mg/mL has been studied as a function of neptunium concentration and pH. The sorption of Np increased as a function of pH for both minerals, attaining a maximum at neutral pH, and then decreased with increasing alkalinity. X-ray absorption fine structure spectroscopy (XAFS), taken at the Np L(III)-edge, has been used to determine the oxidation state of the sorbed Np. Our experimental results indicate reduction of the Np(V) because of interaction with the X-ray beam. These findings significantly impact the interpretation of results reported elsewhere on Np(V) investigated though the use of high-intensity X-ray beams.
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