Impact of phosphate on U(VI) immobilization in the presence of goethite

Singh, Abhas; Ulrich, Kai-Uwe; Giammar, Daniel E.

doi:10.1016/j.gca.2010.08.031

Cited by 102 publications

(102 citation statements)

References 68 publications

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“…The initial U(VI) concentration was lowered to 100 μM in all batches containing phosphate, in order to avoid U(VI) precipitation. 17 The details of all the experimental batches are listed in Table 1. 2.3. Quantification of Uranium, Calcium, and Phosphate.…”

Section: Methodsmentioning

confidence: 99%

Biogeochemical Controls on the Product of Microbial U(VI) Reduction

Stylo

Alessi

Shao

et al. 2013

Environ. Sci. Technol.

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Biologically mediated immobilization of radionuclides in the subsurface is a promising strategy for the remediation of uranium-contaminated sites. During this process, soluble U(VI) is reduced by indigenous microorganisms to sparingly soluble U(IV). The crystalline U(IV) phase uraninite, or UO 2 , is the preferable end-product of bioremediation due to its relatively high stability and low solubility in comparison to biomass-associated nonuraninite U(IV) species that have been reported in laboratory and under field conditions. The goal of this study was to delineate the geochemical conditions that promote the formation of nonuraninite U(IV) versus uraninite and to decipher the mechanisms of its preferential formation. U(IV) products were prepared under varying geochemical conditions and characterized with X-ray absorption spectroscopy (XAS), scanning transmission X-ray microscopy (STXM), and various wet chemical methods. We report an increasing fraction of nonuraninite U(IV) species with decreasing initial U concentration. Additionally, the presence of several common groundwater solutes (sulfate, silicate, and phosphate) promote the formation of nonuraninite U(IV). Our experiments revealed that the presence of those solutes promotes the formation of bacterial extracellular polymeric substances (EPS) and increases bacterial viability, suggesting that the formation of nonuraninite U(IV) is due to a biological response to solute presence during U(VI) reduction. The results obtained from this laboratory-scale research provide insight into biogeochemical controls on the product(s) of uranium reduction during bioremediation of the subsurface.

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Section: Methodsmentioning

confidence: 99%

Biogeochemical Controls on the Product of Microbial U(VI) Reduction

Stylo

Alessi

Shao

et al. 2013

Environ. Sci. Technol.

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“…Reduction or sorption of uranyl by Fe(II)-bearing minerals, which can be present or formed as a result of biological reductive processes, has been reported for ferrous sulfides (Wersin et al, 1994), green rust (O'Loughlin et al, 2003), and Fe(II) sorbed onto goethite (Fredrickson et al, 2000). Similarly, incorporation of oxidized uranium into phosphate minerals (Jerden and Sinha, 2003;Singh et al, 2010) and sorption of U(VI) onto biomass has also been demonstrated to play a role in uranium immobilization (N'Guessan et al, 2008). Analyses of uranium-contaminated sediments in Oak Ridge, TN support the notion of competing mechanisms and concurrent immobilization of both oxidized and reduced species of uranium .…”

mentioning

confidence: 95%

Uranium speciation and stability after reductive immobilization in aquifer sediments

Sharp

Lezama‐Pacheco

Schofield

et al. 2011

Geochimica et Cosmochimica Acta

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114

112

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“…The sorbent was saturated with approximately 50% of the volume passed through the column for pH 7.5. Such behavior can be explained by the species of U 6+ in solution and the presence of other inorganic ligands such as sulphate, carbonate and phosphate [23][24][25][26]. Moreover, the competition of U 6+ for sorption sites with SO 4 2-ions (from the alum shale as shown in Table 1) is higher at lower pH values.…”

Section: Sorption Experimentsmentioning

confidence: 99%

“…Competition for sorption sites is thus enhanced and does have an impact in the U 6+ removal capacity. Such effects could be attributed to anions (carbonates and phosphates) [23][24][25][26], cations (e.g. Ba…”

mentioning

confidence: 99%

Sorption Properties of a Bentonite Based Material for Removal of Uranium from Alum Shale Leachate

Alvarenga¹,

Hayrapetyan²,

Skipperud³

et al. 2016

JCCE

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A dynamic sorption experiment was performed for removal of uranium (VI or 6+) from a leachate from an alum shale landfill with a diatomite-bentonite based sorbent in a laboratory scale. Such material was grounded and treated chemically with H 3 PO 4 (phosphoric acid) and thermally for improving its porosity and resistance to water flow. A specific surface area of 209 m 2 ·g -1 was determined by the BET method. A sorption capacity of 30 µg·g -1 and 0.6 µg·g -1 was obtained at a pH of 7.5 and 4 respectively by means of Langmuir and Freundlich isotherm models. The flow rate of 3 mL·min -1 was effective for controlling the pH inside of the column. The sorption mechanism was investigated along with desorption of the element of interest for further process design considerations for a treatment unit on the landfill site.

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Impact of phosphate on U(VI) immobilization in the presence of goethite

Cited by 102 publications

References 68 publications

Biogeochemical Controls on the Product of Microbial U(VI) Reduction

Biogeochemical Controls on the Product of Microbial U(VI) Reduction

Uranium speciation and stability after reductive immobilization in aquifer sediments

Sorption Properties of a Bentonite Based Material for Removal of Uranium from Alum Shale Leachate

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