Radionuclide Sorption to Rocks and Minerals: Effects of pH and Inorganic Anions. Part 1. Sorption of Cesium, Cobalt, Strontium and Manganese

Fujikawa, Yoko; Fukui, Masami

doi:10.1524/ract.1997.76.3.153

Cited by 28 publications

(13 citation statements)

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“…The surface‐mediated precipitation of Co may be responsible for high apparent surface sorption at high exposure concentrations. In the absence of organic ligands, Co exhibits a high affinity for mineral surfaces, as indicated by solid–solution partitioning coefficients ( K d ), ranging from 10 3 to 10 5 L kg −1 (McLaren et al, 1986; Fujikawa and Fukui, 1997; Barrow and Whelan, 1998).…”

Section: Summary Of X‐ray Absorption Spectroscopy Determined Co Specimentioning

confidence: 99%

Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots

et al. 2011

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The speciation and distribution of Co in soils is poorly understood. This study was conducted using x-ray absorption spectroscopy (XAS) techniques to examine the influence of soluble cobalt in the +2 oxidation state (Co[II]) aging, submergence-dried cycling, and the presence of in vivo rice roots on the speciation and distribution of added Co(II) in soils. In the aging and submerged-dried cycling studies, Co was found to be associated with Mn oxide fraction (23 to 100% of total Co) and Fe oxide fractions (0 to 77% of total Co) of the soils as either Co(II) species or a mixed Co(II), and Co in the +3 oxidation state (Co[III]) species. The surface speciation of Co in the Mn oxide fraction suggests an innersphere complex was present and the speciation of Co in the Fe oxide fraction was an innersphere surface complex. The in vivo root box experiments showed similar Co speciation in the Mn oxide fraction (13 to 76% of total Co) as the aging and submerged-dried cycling studies. However, the Fe oxide fraction of the soil was unimportant in Co retention. A significant amount (24 to 87% of total Co) of the Co in root box treatments was identified as a Co precipitate. The importance of this finding is that in the presence of rice roots, the Co is redistributed to a Co precipitate. This work confirmed earlier macroscopic work that Mn oxides are important in the sequestration of Co in soils and the influence of roots needs to be taken into account when addressing Co speciation. The information gained from this study will be used to improve models to predict the lability and hence the availability of Co in terrestrial environments.

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Section: Summary Of X‐ray Absorption Spectroscopy Determined Co Specimentioning

confidence: 99%

Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots

et al. 2011

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“…The sorption process depends on the electrostatic interaction of solute at the surface of the sediment, the chemical reaction of solute with the sorbing surfaces, precipitation of solute on the sediment surface, and metal dissolution of mineral surfaces. These subjects were extensively reviewed in some previous works [2,3]. Several approaches have been used to describe and create a model for the adsorption reactions.…”

Section: Introductionmentioning

confidence: 99%

The Behaviour of¹³⁴Cs,⁶⁰Co, and⁸⁵Sr Radionuclides in Marine Environmental Sediment

Kamel

2002

The Scientific World JOURNAL

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This work describes experimental investigations and modelling studies on the sorption of radionuclides Cs, Co, and Sr by certain marine sediments within Egypt. The chemical composition of the marine sediments was determined. The soluble salts were measured for the sediments and the concentrations of the released cations, Al, Fe, and Si, were measured for the sediment materials in 0.1 M NaClO4 aqueous solution at different hydrogen ion concentrations. The two main factors that control the uptake of the radionuclides onto the sediment are the pH and the exchangeable capacities of the sediment materials. Surface complex model was used to estimate the surface charge densities and the electric surface potential of the marine sediment materials. These two parameters were calculated at the surface capacity sites of the sediment materials. The desorption of the adsorbed cations was determined by means of selective consecutive extraction tests using different chemical reagents including (1) 1 M MgCl2 (pH 7), (2) 1 M ammonium oxalate (pH 3-5), (3) 0.04 M NH2OH,HCl in 25% acetic acid (pH 3-4), (4) H2O2 in 5% HNO3(pH 2-3), and (5) digestion with nitric acid followed by hydrofluoric and perchloric acids (pH 2).

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“…Cobalt in the absence of organic complexants exhibits cation adsorption behavior. As such, the adsorption of cobalt is zero to minimal at acidic conditions, then increases in the pH range of 4 to 7 with increasing pH, and continues to be high at basic pH conditions (Lowson and Evans 1983;McLaren et al 1986;Fujikawa and Fukui 1997;Barrow and Whelan 1998;and others). Fujikawa and Fuki (1997) noted that in highly basic Na 2 CO 3 solutions, the adsorption of cobalt decreases compared to that at lower pH values.…”

Section: A142 Cobaltmentioning

confidence: 99%

Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

Cantrell¹,

Zachara²,

Dresel³

et al. 2007

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Companion reports that review other subject matter areas relevant to contaminant transport within the vadose zone beneath the SST WMAs, the IDF, and groundwater have been recently published. The specific subject areas include the geology of the SST WMAs iv contaminants released to the vadose zone exhibit a wide range of mobility behaviors. Many tank waste contaminants have been strongly retarded by adsorption and precipitation reactions (e.g., cesium, plutonium, americium, and europium), while others have remained mobile (e.g., technetium, nitrate, and selenium). Still others show variable, waste-specific behaviors (e.g., cesium [where sodium concentrations are very high], strontium, chromium, and uranium) that are closely tied to evolving composition of pore water in the sediments, and for chromium, a change in oxidation state. The temperature of in-ground tank waste has moderated by heat exchange with the subsurface sediment, and high concentrations of base (OH -) have been neutralized through reactions with sediment minerals and secondary mineral precipitation. Major geochemical features that may potentially affect the mobility of key contaminants of interest in the vadose zone include oxidation state, aqueous speciation, solubility, and adsorption reactions.Processes suspected of facilitating the far-field migration of immobile radionuclides, such as formation of stable aqueous complex formation and mobile colloids, were found to be potentially operative, but unlikely to occur in the field. An exception is the enhanced migration of cobalt-60 facilitated by the formation of highly stable aqueous-cyanide complexes. Certain fission-product oxyanions (e. • Adsorption is suppressed by large concentrations of tank waste anions (e.g., NO 3 -, OH -, and CO 3 2-)• Surface charge of clay-size minerals is negative and will therefore tend to repel anions• Unlike chromium, their less-soluble, less-mobile reduced forms are unstable in oxidizing environments.Laboratory studies conducted through PNNL's Vadose Zone Characterization Project and basic-science geochemical studies are expected to continue in partnership to provide information to further refine the conceptual model used for risk assessment modeling. Results of these studies can be used to help ascertain uncertainties associated with the refinement of the conceptual models for contaminant migration in the vadose zone beneath the single-shell tanks. Results can also provide improved parameterization, such as distribution coefficients (K d ), and mathematical constructs used by modelers to predict contaminant mobility under these conditions, and to decrease the degree of conservatism incorporated in these models.For various reasons, risk assessment models typically use various approximations to represent the conceptual model developed for the site. Adsorption is frequently approximated using empirical distribution coefficients (K d s). Although the use of empirical distribution coefficients can potentially lead to erroneous results under certain conditions where the...

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Radionuclide Sorption to Rocks and Minerals: Effects of pH and Inorganic Anions. Part 1. Sorption of Cesium, Cobalt, Strontium and Manganese

Cited by 28 publications

References 0 publications

Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots

Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots

The Behaviour of¹³⁴Cs,⁶⁰Co, and⁸⁵Sr Radionuclides in Marine Environmental Sediment

Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

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Radionuclide Sorption to Rocks and Minerals: Effects of pH and Inorganic Anions. Part 1. Sorption of Cesium, Cobalt, Strontium and Manganese

Cited by 28 publications

References 0 publications

Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots

Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots

The Behaviour of134Cs,60Co, and85Sr Radionuclides in Marine Environmental Sediment

Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

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The Behaviour of¹³⁴Cs,⁶⁰Co, and⁸⁵Sr Radionuclides in Marine Environmental Sediment