The dissolution of synthetic Na-boltwoodite in sodium carbonate solutions

Eugene S. Ilton, Chongxuan Liu, Wassana Yantasee, Zheming Wang, Dean A. Moore, Andrew R. Felmy, John M. Zachara

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Uranyl silicates such as uranophane and Na-boltwoodite appear to control the solubility of uranium in certain contaminated sediments at the US Department of Energy Hanford site [Liu, C., Zachara, J.M., Qafoku, O., McKinley, J.P., Heald, S.M., Wang, Z. 2004. Dissolution of uranyl microprecipitates in subsurface sediments at Hanford Site, USA. Geochim. Cosmochim. Acta 68, 4519-4537.]. Consequently, the solubility of synthetic Na-boltwoodite, Na(UO2)(SiO3OH) · 1.5H2O, was determined over a wide range of bicarbonate concentrations, from circumneutral to alkaline pH, that are representative of porewater and groundwater compositions at the Hanford site and calcareous environments generally. Experiments were open to air. Results show that Na-boltwoodite dissolution was nearly congruent and its solubility and dissolution kinetics increased with increasing bicarbonate concentration and pH. A consistent set of solubility constants were determined from circumneutral pH (0 added bicarbonate) to alkaline pH (50 mM added bicarbonate). Average log Kspo = 5.86 ± 0.24 or 5.85 ± 0.0.26; using the Pitzer ion-interaction model or Davies equation, respectively. These values are close to the one determined by [Nguyen, S.N., Silva, R.J., Weed, H.C., Andrews, Jr., J.E., 1992. Standard Gibbs free energies of formation at the temperature 303.15 K of four uranyl silicates: soddyite, uranophane, sodium boltwoodite, and sodium weeksite. J. Chem. Thermodynamics 24, 359-376.] under very different conditions (pH 4.5, Ar atmosphere).

Original languageEnglish (US)
Pages (from-to)4836-4849
Number of pages14
JournalGeochimica et Cosmochimica Acta
Volume70
Issue number19
DOIs
StatePublished - Oct 1 2006
Externally publishedYes

Fingerprint

Bicarbonates
bicarbonate
Dissolution
solubility
Solubility
dissolution
sodium
carbonate
Silicates
Sediments
silicate
Sodium
Uranium
Gibbs free energy
sediment
weed
Groundwater
uranium
porewater
thermodynamics

ASJC Scopus subject areas

  • Geochemistry and Petrology

Cite this

Ilton, E. S., Liu, C., Yantasee, W., Wang, Z., Moore, D. A., Felmy, A. R., & Zachara, J. M. (2006). The dissolution of synthetic Na-boltwoodite in sodium carbonate solutions. Geochimica et Cosmochimica Acta, 70(19), 4836-4849. https://doi.org/10.1016/j.gca.2006.06.1553

The dissolution of synthetic Na-boltwoodite in sodium carbonate solutions. / Ilton, Eugene S.; Liu, Chongxuan; Yantasee, Wassana; Wang, Zheming; Moore, Dean A.; Felmy, Andrew R.; Zachara, John M.

In: Geochimica et Cosmochimica Acta, Vol. 70, No. 19, 01.10.2006, p. 4836-4849.

Research output: Contribution to journalArticle

Ilton, ES, Liu, C, Yantasee, W, Wang, Z, Moore, DA, Felmy, AR & Zachara, JM 2006, 'The dissolution of synthetic Na-boltwoodite in sodium carbonate solutions', Geochimica et Cosmochimica Acta, vol. 70, no. 19, pp. 4836-4849. https://doi.org/10.1016/j.gca.2006.06.1553
Ilton, Eugene S. ; Liu, Chongxuan ; Yantasee, Wassana ; Wang, Zheming ; Moore, Dean A. ; Felmy, Andrew R. ; Zachara, John M. / The dissolution of synthetic Na-boltwoodite in sodium carbonate solutions. In: Geochimica et Cosmochimica Acta. 2006 ; Vol. 70, No. 19. pp. 4836-4849.
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