title: Controls on soluble Pu concentrations in PuO2/magnetite suspensions.
abstract: Time-dependent reduction of PuO(2)(am) was studied over a range of pH values in the presence of aqueous Fe(II) and magnetite (Fe(3)O(4)) nanoparticles. At early time frames (up to 56 days) very little aqueous Pu was mobilized from PuO(2)(am), even though measured pH and redox potentials, coupled to equilibrium thermodynamic modeling, indicated the potential for significant reduction of PuO(2)(am) to relatively soluble Pu(III). Introduction of Eu(III) or Nd(III) to the suspensions as competitive cations to displace possible sorbed Pu(III) resulted in the release of significant concentrations of aqueous Pu. However, the similarity of aqueous Pu concentrations that resulted from the introduction of Eu(III)/Nd(III) to suspensions with and without magnetite indicated that the Pu was solubilized from PuO(2)(am), not from magnetite.
authors.affiliation: Pacific Northwest National Laboratory, Richland, Washington, USA. ar.felmy@pnnl.gov
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Felmy
authors.forename: Dean A
authors.initials: DA
authors.lastname: Moore
authors.forename: Carolyn I
authors.initials: CI
authors.lastname: Pearce
authors.forename: Steven D
authors.initials: SD
authors.lastname: Conradson
authors.forename: Odeta
authors.initials: O
authors.lastname: Qafoku
authors.forename: Edgar C
authors.initials: EC
authors.lastname: Buck
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Rosso
authors.forename: Eugene S
authors.initials: ES
authors.lastname: Ilton
mesh_terms: D005063:Europium / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D009354:Neodymium / Q000737:chemistry; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D011005:Plutonium / Q000737:chemistry*; D013535:Suspensions; D014875:Water Pollutants, Radioactive / Q000737:chemistry
chemical_list: D058185:Magnetite Nanoparticles; D010087:Oxides; D013535:Suspensions; D014875:Water Pollutants, Radioactive; D009354:Neodymium; D005063:Europium; D011005:Plutonium; D007501:Iron