Sorption Behavior and Morphology of Plutonium in the Presence of Goethite at 25 and 80C

Zavarin, Mavrik; Zhao, Ping; Dai, Zhicheng; Carroll, Susan; Kersting, Annie B.

doi:10.2172/1046119

Cited by 3 publications

(6 citation statements)

References 25 publications

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“…Besides sorption of plutonium ions onto solid phases, sorption of hydrated plutonium oxide colloids onto solids may occur. This was shown in tests for which 2-5-nm colloids of PuO 2 •xH 2 O were prepared at pH ~8.5 by adding NaOH solution and buffer to an acidic Pu(IV) solution (Zavarin et al 2012). The plutonium colloid particle size range is remarkably consistent with that observed in various other investigations, including PuO 2 •xH 2 O prepared in molar NaOH solution (Delegard (2013) and references therein).…”

Section: Sorption/adsorptionmentioning

confidence: 94%

Chemical Disposition of Plutonium in Hanford Site Tank Wastes

Delegard

Jones

2015

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This report examines the chemical disposition of plutonium (Pu) in Hanford Site tank wastes, by itself and in its observed and potential interactions with the neutron absorbers aluminum (Al), cadmium (Cd), chromium (Cr), iron (Fe), manganese (Mn), nickel (Ni), and sodium (Na). Consideration also is given to the interactions of plutonium with uranium (U). No consideration of the disposition of uranium itself as an element with fissile isotopes is considered except tangentially with respect to its interaction as an absorber for plutonium. into plutonium and absorber element behavior under alkaline and plant process conditions. Three external reviewers, Scott Barney, independent consultant, and David Hobbs and Tracy Rudisill of the Savannah River National Laboratory examined the near-complete document and provided insightful, germane, and complementary comments. We thank Reid Peterson (PNNL) for project oversight and Lisa Staudinger (PNNL) for her attention and care in formatting and technically editing this manuscript. Finally, we gratefully acknowledge the fundamental and applied research into the chemistry of plutonium and other transuranic elements in alkaline media conducted by scientists and technicians of the Institute of Physical Chemistry of the Russian Academy of Sciences. In particular we note the scientific leadership of Professors

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Section: Sorption/adsorptionmentioning

confidence: 94%

Chemical Disposition of Plutonium in Hanford Site Tank Wastes

Delegard

Jones

2015

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“…89 This epitaxial distortion was also shown to occur for Pu(IV) on goethite at elevated temperatures (80 °C). 76 For high-level waste repositories, alteration of the engineered barrier materials as well as degradation of the waste form may produce mineral or organic colloids very different from those observed in the natural environment. Buck and Bates conducted a series of hydrothermal experiments investigating the colloid formation of altered borosilicate nuclear waste glass.…”

Section: ■ Microbial Colloid Interactions With Pumentioning

confidence: 99%

“…In contrast to Pu(IV), the rate of sorption of Pu(V) is slow and has been shown to result from the surface-mediated reduction of Pu(V) to Pu(IV). ,,,− Although Pu sorbs to all minerals, in general redox-reactive minerals (e.g., manganese oxide and iron oxide) sorb Pu faster and more strongly than non-redox-reactive minerals (e.g., quartz, gibbsite, and clay). This reduction has been documented even on minerals that would typically be considered as oxidizing or redox-inactive such as pyrolusite, birnessite, hematite, goethite, montmorillonite, silica, and gibbsite.…”

Section: Inorganic Colloid Interactions With Pumentioning

confidence: 99%

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Plutonium Transport in the Environment

2013

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The recent estimated global stockpile of separated plutonium (Pu) worldwide is about 500 t, with equal contributions from nuclear weapons and civilian nuclear energy. Independent of the United States' future nuclear energy policy, the current large and increasing stockpile of Pu needs to be safely isolated from the biosphere and stored for thousands of years. Recent laboratory and field studies have demonstrated the ability of colloids (1-1000 nm particles) to facilitate the migration of strongly sorbing contaminants such as Pu. In understanding the dominant processes that may facilitate the transport of Pu, the initial source chemistry and groundwater chemistry are important factors, as no one process can explain all the different field observations of Pu transport. Very little is known about the molecular-scale geochemical and biochemical mechanisms controlling Pu transport, leaving our conceptual model incomplete. Equally uncertain are the conditions that inhibit the cycling and mobility of Pu in the subsurface. Without a better mechanistic understanding for Pu at the molecular level, we cannot advance our ability to model its transport behavior and achieve confidence in predicting long-term transport. Without a conceptual model that can successfully predict long-term Pu behavior and ultimately isolation from the biosphere, the public will remain skeptical that nuclear energy is a viable and an attractive alternative to counter global warming effects of carbon-based energy alternatives. This review summarizes our current understanding of the relevant conditions and processes controlling the behavior of Pu in the environment, gaps in our scientific knowledge, and future research needs.

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“…However, an opposite trend in their size was shown according to the results of DLS (Triay et al, 1991), XRD (Delegard, 2013), LIBD (Rothe et al, 2004), and ultracentrifuge (Ichikawa and Sato, 1984). In addition, different shapes and appearances of the polymers either aggregated or grown on mineral surfaces were observed (Thiyagarajan et al, 1990;Powell et al, 2011;Zavarin et al, 2012). Recently, researchers indicated that Pu intrinsic colloid was characterized by crystalline structures (Soderholm et al, 2008;Powell et al, 2011;Delegard, 2013;Romanchuk et al, 2013).…”

Section: Accepted Manuscriptmentioning

confidence: 99%