Experimental study and modeling of the sorption of uranium(VI) onto olivine-rock

Aamrani, F.Z. El; Duro, Lara; Pablo, Joan de; Bruno, Jordi

doi:10.1016/s0883-2927(01)00115-9

Cited by 38 publications

(20 citation statements)

References 22 publications

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“…Following the concept of the ''Generalised Composite Approach" (Davis et al, 1998;Davis et al, 2004), we merged these sites into a single generic site because it would not appear feasible to quantify or characterize the specific site types for a complex rock such as basalt. The approximation of considering only one generic >SOH site was also made by Wanner et al (1994), Sverjensky and Sahai (1996) and El Aamrani et al (2002) in studies dealing with complex silicate mineral surfaces. For the generic site, we determined only REE sorption constants.…”

Section: Surface Complexation Modelmentioning

confidence: 99%

“…Different approaches have been used to model whole-rock or bulk sediment sorption processes. El Aamrani et al (2002), Barnett et al (2002), Davis et al (2004) and Payne et al (2004) interpreted sorption data of Uranium VI by olivine rock, different American soils, an aquifer sediment and a weathered shale, using either (1) the component additivity model (CA) or (2) the Generalised Composite model (GC). These two approaches were described in detail by Davis et al (1998) and Davis et al (2004).…”

Section: Introductionmentioning

confidence: 99%

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Rare earth element sorption by basaltic rock: Experimental data and modeling results using the “Generalised Composite approach”

Tertre¹,

Hofmann²,

Berger

2008

Geochimica et Cosmochimica Acta

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Sorption of the 14 rare earth elements (REE) by basaltic rock is investigated as a function of pH, ionic strength and aqueous REE concentrations. The rock sample, originating from a terrestrial basalt flow (Rio Grande do Sul State, Brazil), is composed of plagioclase, pyroxene and cryptocrystalline phases. Small amounts of clay minerals are present, due to rock weathering. Batch sorption experiments are carried out under controlled temperature conditions of 20°C with the <125 lm fraction of the ground rock in solutions of 0.025 M and 0.5 M NaCl and at pH ranging from 2.7 to 8. All 14 REEs are investigated simultaneously with initial concentrations varying from 10 À7 to 10 À4 mol/L. Some experiments are repeated with only europium present to evaluate possible competitive effects between REE. Experimental results show the preferential retention of the heavy REEs at high ionic strength and circumneutral pH conditions. Moreover, results show that REE sorption increases strongly with decreasing ionic strength, indicating two types of sorption sites: exchange and specific sites. Sorption data are described by a Generalised Composite (GC) non-electrostatic model: two kinds of surface reactions are treated, i.e. cation exchange at >XNa sites, and surface complexation at >SOH sites. Total site density (>XNa + >SOH) is determined by measuring the cation exchange capacity (CEC = 52 lmol/m 2 ). Specific concentrations of exchange sites and complexation sites are determined by fitting the Langmuir equation to sorption isotherms of REE and phosphate ions. Site densities of 22 ± 5 and 30 ± 5 lmol/m 2 are obtained for [>XNa] and [>SOH], respectively. The entire set of REE experimental data is modeled using a single exchange constant (log K ex = 9.7) and a surface complexation constant that progressively increases from log K = À1.15 for La(III) to À0.4 for Lu(III).The model proves to be fairly robust in describing other aluminosilicate systems. Maintaining the same set of sorption constants and only adjusting the site densities, we obtain good agreement with the literature data on REE/kaolinite and REE/ smectite sorption. The Generalised Composite non-electrostatic model appears as an easy and efficient tool for describing sorption by complex aluminosilicate mineral assemblages.

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Section: Surface Complexation Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rare earth element sorption by basaltic rock: Experimental data and modeling results using the “Generalised Composite approach”

Tertre¹,

Hofmann²,

Berger

2008

Geochimica et Cosmochimica Acta

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“…Sorption studies with U(VI) typically demonstrate that it has low affinity for zeolites at high pH (9-11)-particularly in the presence of elevated inorganic carbon. 23,24,25,26 This is because the higher levels of dissolved inorganic carbon favor the formation of negatively-charged, highly soluble U(VI)-carbonate complexes, which have low affinities for similarly-charged surfaces. Few sorption studies have been done with U and zeolites above pH 12.…”

Section: +mentioning

confidence: 99%

Characterization of Uranium in Archived 2H Evaporator Scale

Duff¹

2004

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“…Chemical and physical methods, including excavation and soil capping [21,22], pump and treat technologies [23,24], mineral adsorption [25][26][27], mineral precipitation [28,29], complexation [30][31][32], adsorption to permeable zero-valent iron and hydroxyapatite reactive barriers [33][34][35], cement solidification [36,37], and vitrification [38,39], have all demonstrated efficacy in mitigating contaminant transport in situ. Remediation methods that depend upon chemical transformations for in situ sequestration of contaminants must first consider local geochemical parameters that include local geology, concentrations of soluble anions and cations, pH, and redox state.…”

Section: Introductionmentioning

confidence: 99%

Phosphate-Mediated Remediation of Metals and Radionuclides

Martinez

Beazley

Sobecky

2014

Advances in Ecology

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Worldwide industrialization activities create vast amounts of organic and inorganic waste streams that frequently result in significant soil and groundwater contamination. Metals and radionuclides are of particular concern due to their mobility and longterm persistence in aquatic and terrestrial environments. As the global population increases, the demand for safe, contaminantfree soil and groundwater will increase as will the need for effective and inexpensive remediation strategies. Remediation strategies that include physical and chemical methods (i.e., abiotic) or biological activities have been shown to impede the migration of radionuclide and metal contaminants within soil and groundwater. However, abiotic remediation methods are often too costly owing to the quantities and volumes of soils and/or groundwater requiring treatment. The in situ sequestration of metals and radionuclides mediated by biological activities associated with microbial phosphorus metabolism is a promising and less costly addition to our existing remediation methods. This review highlights the current strategies for abiotic and microbial phosphatemediated techniques for uranium and metal remediation.

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Experimental study and modeling of the sorption of uranium(VI) onto olivine-rock

Cited by 38 publications

References 22 publications

Rare earth element sorption by basaltic rock: Experimental data and modeling results using the “Generalised Composite approach”

Rare earth element sorption by basaltic rock: Experimental data and modeling results using the “Generalised Composite approach”

Characterization of Uranium in Archived 2H Evaporator Scale

Phosphate-Mediated Remediation of Metals and Radionuclides

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