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Immobilization of Hg(II) by Coprecipitation in Sulfate-Cement Systems
[Image: see text] Uptake and molecular speciation of dissolved Hg during formation of Al- or Fe-ettringite-type and high-pH phases were investigated in coprecipitation and sorption experiments of sulfate-cement treatments used for soil and sediment remediation. Ettringite and minor gypsum were ident...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2012
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3381454/ https://www.ncbi.nlm.nih.gov/pubmed/22594782 http://dx.doi.org/10.1021/es202939v |
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author | Serrano, Susana Vlassopoulos, Dimitri Bessinger, Brad O’Day, Peggy A. |
author_facet | Serrano, Susana Vlassopoulos, Dimitri Bessinger, Brad O’Day, Peggy A. |
author_sort | Serrano, Susana |
collection | PubMed |
description | [Image: see text] Uptake and molecular speciation of dissolved Hg during formation of Al- or Fe-ettringite-type and high-pH phases were investigated in coprecipitation and sorption experiments of sulfate-cement treatments used for soil and sediment remediation. Ettringite and minor gypsum were identified by XRD as primary phases in Al systems, whereas gypsum and ferrihydrite were the main products in Hg–Fe precipitates. Characterization of Hg–Al solids by bulk Hg EXAFS, electron microprobe, and microfocused-XRF mapping indicated coordination of Hg by Cl ligands, multiple Hg and Cl backscattering atoms, and concentration of Hg as small particles. Thermodynamic predictions agreed with experimental observations for bulk phases, but Hg speciation indicated lack of equilibration with the final solution. Results suggest physical encapsulation of Hg as a polynuclear chloromercury(II) salt in ettringite as the primary immobilization mechanism. In Hg–Fe solids, structural characterization indicated Hg coordination by O atoms only and Fe backscattering atoms that is consistent with inner-sphere complexation of Hg(OH)(2)(0) coprecipitated with ferrihydrite. Precipitation of ferrihydrite removed Hg from solution, but the resulting solid was sufficiently hydrated to allow equilibration of sorbed Hg species with the aqueous solution. Electron microprobe XRF characterization of sorption samples with low Hg concentration reacted with cement and FeSO(4) amendment indicated correlation of Hg and Fe, supporting the interpretation of Hg removal by precipitation of an Fe(III) oxide phase. |
format | Online Article Text |
id | pubmed-3381454 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-33814542012-06-25 Immobilization of Hg(II) by Coprecipitation in Sulfate-Cement Systems Serrano, Susana Vlassopoulos, Dimitri Bessinger, Brad O’Day, Peggy A. Environ Sci Technol [Image: see text] Uptake and molecular speciation of dissolved Hg during formation of Al- or Fe-ettringite-type and high-pH phases were investigated in coprecipitation and sorption experiments of sulfate-cement treatments used for soil and sediment remediation. Ettringite and minor gypsum were identified by XRD as primary phases in Al systems, whereas gypsum and ferrihydrite were the main products in Hg–Fe precipitates. Characterization of Hg–Al solids by bulk Hg EXAFS, electron microprobe, and microfocused-XRF mapping indicated coordination of Hg by Cl ligands, multiple Hg and Cl backscattering atoms, and concentration of Hg as small particles. Thermodynamic predictions agreed with experimental observations for bulk phases, but Hg speciation indicated lack of equilibration with the final solution. Results suggest physical encapsulation of Hg as a polynuclear chloromercury(II) salt in ettringite as the primary immobilization mechanism. In Hg–Fe solids, structural characterization indicated Hg coordination by O atoms only and Fe backscattering atoms that is consistent with inner-sphere complexation of Hg(OH)(2)(0) coprecipitated with ferrihydrite. Precipitation of ferrihydrite removed Hg from solution, but the resulting solid was sufficiently hydrated to allow equilibration of sorbed Hg species with the aqueous solution. Electron microprobe XRF characterization of sorption samples with low Hg concentration reacted with cement and FeSO(4) amendment indicated correlation of Hg and Fe, supporting the interpretation of Hg removal by precipitation of an Fe(III) oxide phase. American Chemical Society 2012-05-17 2012-06-19 /pmc/articles/PMC3381454/ /pubmed/22594782 http://dx.doi.org/10.1021/es202939v Text en Copyright © 2012 American Chemical Society http://pubs.acs.org This is an open-access article distributed under the ACS AuthorChoice Terms & Conditions. Any use of this article, must conform to the terms of that license which are available at http://pubs.acs.org. |
spellingShingle | Serrano, Susana Vlassopoulos, Dimitri Bessinger, Brad O’Day, Peggy A. Immobilization of Hg(II) by Coprecipitation in Sulfate-Cement Systems |
title | Immobilization of Hg(II) by Coprecipitation in Sulfate-Cement
Systems |
title_full | Immobilization of Hg(II) by Coprecipitation in Sulfate-Cement
Systems |
title_fullStr | Immobilization of Hg(II) by Coprecipitation in Sulfate-Cement
Systems |
title_full_unstemmed | Immobilization of Hg(II) by Coprecipitation in Sulfate-Cement
Systems |
title_short | Immobilization of Hg(II) by Coprecipitation in Sulfate-Cement
Systems |
title_sort | immobilization of hg(ii) by coprecipitation in sulfate-cement
systems |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3381454/ https://www.ncbi.nlm.nih.gov/pubmed/22594782 http://dx.doi.org/10.1021/es202939v |
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