The effect of high ionic strength on neptunium (V) adsorption to a halophilic bacterium

David, Arun Alfred; Swanson, Juliet S.; Szymanowski, Jennifer E. S.; Fein, Jeremy B.; Richmann, Michael K.; Reed, Donald T.

doi:10.1016/j.gca.2013.01.024

Cited by 28 publications

(13 citation statements)

References 47 publications

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“…Only few studies deal with radionuclide sorption onto clay materials under saline conditions as recently reviewed by Vilks (2011). A surface complexation approach is described by Ams et al (2013) while studying the adsorption of Np onto bacteria at high ionic strength. They observed enhanced Np adsorption at increasing the NaClO 4 background concentration from 2.2 m to 4.9 m and modeled their data using a non-electrostatic surface complexation model deriving conditional constants (i.e.…”

Section: Introductionmentioning

confidence: 99%

Sorption of Cm(III) and Eu(III) onto clay minerals under saline conditions: Batch adsorption, laser-fluorescence spectroscopy and modeling

Schnurr

Marsac

Rabung

et al. 2015

Geochimica et Cosmochimica Acta

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The present work reports experimental data for trivalent metal cation (Cm/Eu) sorption onto illite (Illite du Puy) and montmorillonite (Na-SWy-2) in NaCl solutions up to 4.37 molal (m) in the absence of carbonate. Batch sorption experiments were carried out for a given ionic strength at fixed metal concentration ([Eu] total = 2 × 10-7 mol/kg, labeled with 152 Eu for γ-counting) and at a constant solid to liquid ratio (S:L = 2 g/L) for 3 < pH m < 12 (pH m =-log m H+). The amount of clay sorbed Eu approaches almost 100% (with log K D > 5) for pH m > 8, irrespective of the NaCl concentration. Variations in Eu(III) uptake are minor at elevated NaCl concentrations. Time-resolved laser fluorescence spectroscopy (TRLFS) studies on Cm(III) sorption covering a wide range of NaCl concentrations reveal nearly identical fluorescence emission spectra after peak deconvolution, i.e. no significant variation of Cm(III) surface speciation with salinity. Beyond the three surface complexes already found in previous studies an additional inner-sphere surface species with a fluorescence peak maximum at higher wavelength (λ ~ 610 nm) could be resolved. This new surface species appears in the high pH range and is assumed to correspond to a clay/curium/silicate complex as already postulated in the literature for kaolinite. The 2 site protolysis non-electrostatic surface complexation and cation exchange sorption model (2SPNE SC/CE) was applied to describe Eu sorption data by involving the Pitzer and SIT (specific ion interaction) formalism in the calculation of the activities of dissolved aqueous species. Good agreement of model and experiment is achieved for sorption data at pH m < 6 without the need of adjusting surface complexation constants. For pH m > 6 in case of illite and pH m > 8 in case of montmorillonite calculated sorption data systematically fall below experimental data with increasing ionic strength. Under those conditions sorption is almost quantitative and deviations must be 3 discussed considering uncertainties of measured europium concentrations in the range of analytical detection limits.

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Section: Introductionmentioning

confidence: 99%

Sorption of Cm(III) and Eu(III) onto clay minerals under saline conditions: Batch adsorption, laser-fluorescence spectroscopy and modeling

Schnurr

Marsac

Rabung

et al. 2015

Geochimica et Cosmochimica Acta

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“…Finally, non-electrostatic models were recently shown to be particularly suitable for the prediction of metal ion sorption to various types of surfaces in brines [3,[9][10][11], which is further demonstrated in this study, and would find applications not only in the field of nuclear waste disposal but also, for instance, in marine chemistry. …”

Section: Discussionmentioning

confidence: 76%

“…Previous studies performed at high ionic strength show that nonelectrostatic sorption models are quite suitable to simulate proton and metal ion sorption to naturally occurring surfaces, e.g. marine microalgae or bacteria [9][10][11]. Recently, Eu(III) sorption to illite and smectite was investigated in 0.1 < < 3.9 m [3].…”

Section: Introductionmentioning

confidence: 99%

Sorption and redox speciation of plutonium at the illite surface under highly saline conditions

Marsac

Banik

Lützenkirchen

et al. 2017

Journal of Colloid and Interface Science

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Abstract. Natural groundwater may contain high salt concentrations, such as those occurring at several potential deep geological nuclear waste repository sites. Actinide sorption to clays (e.g. illite) under saline conditions has, however, been rarely studied. Furthermore, both illite surface and ionic strength may affect redox speciation of actinides like plutonium. In the present study, Pu sorption to illite is investigated under anaerobic conditions for 3 < pH m (= -log ) < 10 and = 1.0 and 3.2 molal (m). Results are compared with previous data for = 0.1 m.According to redox potential measurements and based on Eu(III)-illite sorption data (taken as analogue of Pu(III)), the strong effect of on overall Pu uptake observed for pH m < 6 is mainly attributed to the presence of Pu(III) and its competition with Na + for ion exchange sites.For pH m > 6, overall Pu uptake is largely insensitive to due to the prevalence of strongly adsorbed Pu(IV). By applying appropriate corrections to the activity coefficients of dissolved ions and using the 2-site protolysis non-electrostatic surface complexation and cation exchange (2 SPNE SC/CE) model, experimental data on Pu sorption to illite as a function of pH, Eh and can be very well reproduced.Keywords: Plutonium, illite, clay, saline, speciation, redox, sorption, surface complexation model, ion exchange. Graphical Abstract

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“…However, this may not hold true for all archaea. Neptunium sorption onto a halophilic bacterium in sodium perchlorate media increased with increasing ionic strength, likely as a result of increased Np(V) ion activity at higher ionic strength (Ams et al, 2013). This ionic strength dependence did not hold for complex, magnesium-containing brines, as a result of competition with Mg for cell surface sorption sites and potential changes in Np speciation due to inorganic complexation (e.g.…”

Section: Radionuclide Uptakementioning

confidence: 95%

“…Although few surface sorption studies have been conducted at high ionic strength, significant progress has been made in this area (Ams et al, 2013;Reed et al, 2013;Bader et al, submitted). Surface sorption of metals occurs through their interaction with anionic functional groups in cell walls.…”

Section: Radionuclide Uptakementioning

confidence: 99%

Microbial Influence on the Performance of Subsurface, Salt-Based Radioactive Waste Repositories

2018

Radioactive Waste Management

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The effect of high ionic strength on neptunium (V) adsorption to a halophilic bacterium

Cited by 28 publications

References 47 publications

Sorption of Cm(III) and Eu(III) onto clay minerals under saline conditions: Batch adsorption, laser-fluorescence spectroscopy and modeling

Sorption of Cm(III) and Eu(III) onto clay minerals under saline conditions: Batch adsorption, laser-fluorescence spectroscopy and modeling

Sorption and redox speciation of plutonium at the illite surface under highly saline conditions

Microbial Influence on the Performance of Subsurface, Salt-Based Radioactive Waste Repositories

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