Thermodynamic Properties of Autunite, Uranyl Hydrogen Phosphate, and Uranyl Orthophosphate from Solubility and Calorimetric Measurements

Gorman‐Lewis, Drew; Shvareva, Tatiana Y.; Kubatko, Karrie Ann; Burns, Peter C.; Wellman, Dawn M.; McNamara, Bruce K.; Szymanowski, Jennifer E. S.; Navrotsky, Alexandra; Fein, Jeremy B.

doi:10.1021/es9012933

Cited by 85 publications

(57 citation statements)

References 25 publications

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“…In the calculations, we assume water activities of unity, and the equilibrium constant values that were used for Reactions 1-3 were 10 À13.17 , 10 À43.53 , and 10 À53.28 , respectively (Martell and Smith, 2001;Gorman-Lewis et al, 2009;Zhu et al, 2009). …”

Section: Saturation States Calculationsmentioning

confidence: 99%

“…The total dissolved P concentration for the calculation was fixed at the average P concentration from the biogenic HUP solubility experiments. The model was used to calculate the expected U concentration based on the solubility product for macroscopic HUP reported by Gorman-Lewis et al (2009).…”

Section: Hup Solubility Calculationmentioning

confidence: 99%

“…Measured U and P concentrations from the solubility experiments involving biogenic hydrogen uranyl phosphate (HUP) precipitates. Model P concentrations were fixed at the average experimental value, and the model U line is the calculated U concentration in equilibrium with macroscopic HUP, using the Ksp value reported by Gorman-Lewis et al (2009). librium constants shown in Table EA1. At the measured equilibrium P concentration of our biogenic HUP solubility experiment, macroscopic HUP would be in equilibrium with a solution with a U log molality of À5.86 (À0.10/+0.08).…”

Section: Solubilitymentioning

confidence: 99%

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The effects of non-metabolizing bacterial cells on the precipitation of U, Pb and Ca phosphates

Dunham‐Cheatham

Xue

Bunker

et al. 2011

Geochimica et Cosmochimica Acta

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In this study, we test the potential for passive cell wall biomineralization by determining the effects of non-metabolizing bacteria on the precipitation of uranyl, lead, and calcium phosphates from a range of over-saturated conditions. Experiments were performed using Gram-positive Bacillus subtilis and Gram-negative Shewanella oneidensis MR-1. After equilibration, the aqueous phases were sampled and the remaining metal and P concentrations were analyzed using inductively coupled plasmaoptical emission spectroscopy (ICP-OES); the solid phases were collected and analyzed using X-ray diffractometry (XRD), transmission electron microscopy (TEM), and X-ray absorption spectroscopy (XAS).At the lower degrees of over-saturation studied, bacterial cells exerted no discernable effect on the mode of precipitation of the metal phosphates, with homogeneous precipitation occurring exclusively. However, at higher saturation states in the U system, we observed heterogeneous mineralization and extensive nucleation of hydrogen uranyl phosphate (HUP) mineralization throughout the fabric of the bacterial cell walls. This mineral nucleation effect was observed in both B. subtilis and S. oneidensis cells. In both cases, the biogenic mineral precipitates formed under the higher saturation state conditions were significantly smaller than those that formed in the abiotic controls.The cell wall nucleation effects that occurred in some of the U systems were not observed under any of the saturation state conditions studied in the Pb or Ca systems. The presence of B. subtilis significantly decreased the extent of precipitation in the U system, but had little effect in the Pb and Ca systems. At least part of this effect is due to higher solubility of the nanoscale HUP precipitate relative to macroscopic HUP. This study documents several effects of non-metabolizing bacterial cells on the nature and extent of metal phosphate precipitation. Each of these effects likely contributes to higher metal mobilities in geologic media, but the effects are not universal, and occur only with some elements and only under a subset of the conditions studied.

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Section: Saturation States Calculationsmentioning

confidence: 99%

Section: Hup Solubility Calculationmentioning

confidence: 99%

Section: Solubilitymentioning

confidence: 99%

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The effects of non-metabolizing bacterial cells on the precipitation of U, Pb and Ca phosphates

Dunham‐Cheatham

Xue

Bunker

et al. 2011

Geochimica et Cosmochimica Acta

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“…Enthalpies of formation, together with Gibbs free energies of formation of these phases derived from solubility measurements, can be used to calculate entropies of formation as well, and this approach has been applied to a range of uranyl oxide hydrate phases (Gorman-Lewis et al, 2008a), uranyl phosphate phases (Gorman-Lewis et al, 2009), and to the uranyl silicate soddyite (Gorman-Lewis et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic characterization of boltwoodite and uranophane: Enthalpy of formation and aqueous solubility

Shvareva

Mazeina

Gorman‐Lewis

et al. 2011

Geochimica et Cosmochimica Acta

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“…Literature data suggest the low solubility and high stability of many uranyl-phosphate minerals (Felmy et al, 2003;Gorman -Lewis et al, 2009). The solubility constant of the calcium form of autunite, log K sp , has been measured as -44.7 (Grenthe et al, 1992; …”

Section: Introductionmentioning

confidence: 99%

Effect of pH and temperature on the carbonate promoted dissolution of sodium meta-autunite

Gudavalli¹

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This dissertation, written by Ravi Krishna Prasanth Gudavalli, and entitled, "Effect of pH and temperature on the carbonate promoted dissolution of sodium meta-autunite", having been approved in respect to style and intellectual content, is referred to you for judgment.We have read this dissertation and recommend that it be approved. Release of uranium from Na-autunite, an artificial mineral created as a result of polyphosphate injection in the subsurface at the DOE Hanford Site, takes place during slow dissolution of the mineral structure. Stability information of the uranyl-phosphate phases is limited to conditions involving pH, temperature, and a few aqueous organic materials. The carbonate ion, which creates very strong complexes with uranium, is the predominant ion in the groundwater composition. _______________________________________The polyphosphate technology with the formation of autunite was identified as the most feasible remediation strategy to sequester uranium in contaminated groundwater and soil in situ. The objectives of the experimental work were (i) to quantify the effect of bicarbonate on the stability of synthetic sodium meta-autunite created as a result of uranium stabilization through polyphosphate injection, (ii) calculate the kinetic rate law parameters of the uranium release from Na-autunite during dissolution, and (iii) to compare the process parameters with those obtained for natural calcium meta-autunite.Experiments were conducted using SPTF apparatus, which consists of syringe pumps for

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Thermodynamic Properties of Autunite, Uranyl Hydrogen Phosphate, and Uranyl Orthophosphate from Solubility and Calorimetric Measurements

Cited by 85 publications

References 25 publications

The effects of non-metabolizing bacterial cells on the precipitation of U, Pb and Ca phosphates

The effects of non-metabolizing bacterial cells on the precipitation of U, Pb and Ca phosphates

Thermodynamic characterization of boltwoodite and uranophane: Enthalpy of formation and aqueous solubility

Effect of pH and temperature on the carbonate promoted dissolution of sodium meta-autunite

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