Examination of Cr(VI) treatment by zero-valent iron using in situ, real-time X-ray absorption spectroscopy and Cr isotope measurements.
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| Title: | Examination of Cr(VI) treatment by zero-valent iron using in situ, real-time X-ray absorption spectroscopy and Cr isotope measurements. |
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| Authors: | Jamieson-Hanes, Julia H.1, Lentz, Adam M.1, Amos, Richard T.1, Ptacek, Carol J.1, Blowes, David W.1 blowes@uwaterloo.ca |
| Source: | Geochimica et Cosmochimica Acta. Oct2014, Vol. 142, p299-313. 15p. |
| Subjects: | Iron, X-ray absorption, Chromium isotopes, Groundwater analysis, Geochemistry |
| Abstract: | A series of replicate flow-through cell experiments was conducted to characterize Cr isotope fractionation during Cr(VI) treatment by granular zero-valent iron (ZVI). Synthetic groundwater containing 50 mg L −1 Cr(VI) was pumped upward through a custom-made cell packed with ZVI under anaerobic conditions. The geochemical evolution of the system was monitored using pH and redox measurements, while aqueous effluent samples were retained for analysis of cations and Cr isotopes. Real-time, in situ X-ray absorption near edge structure (XANES) spectroscopy collected via a Kapton® window in the cell provided additional information on the speciation of the reaction products. Increases in δ 53 Cr values corresponding to decreases in Cr(VI) concentration suggested the occurrence of redox processes. Spectroscopic results correlated well with the isotope data, indicating reduction of Cr(VI) to Cr(III). The isotope data did not appear to follow a single trend. A two-stage system was proposed to explain the complex isotope trend, where the rapid Cr removal was associated with very little fractionation ( ε = −0.2‰), whereas slower removal was associated with a greater degree of fractionation ( ε = −1.2‰ to −1.5‰). Reactive transport modeling was used to quantify distinct isotope fractionation values ( ε ), differentiated by a significant change in the Cr removal rate. [ABSTRACT FROM AUTHOR] |
| Copyright of Geochimica et Cosmochimica Acta is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 98601092 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Examination of Cr(VI) treatment by zero-valent iron using in situ, real-time X-ray absorption spectroscopy and Cr isotope measurements. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Jamieson-Hanes%2C+Julia+H%2E%22">Jamieson-Hanes, Julia H.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Lentz%2C+Adam+M%2E%22">Lentz, Adam M.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Amos%2C+Richard+T%2E%22">Amos, Richard T.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Ptacek%2C+Carol+J%2E%22">Ptacek, Carol J.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Blowes%2C+David+W%2E%22">Blowes, David W.</searchLink><relatesTo>1</relatesTo><i> blowes@uwaterloo.ca</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Geochimica+et+Cosmochimica+Acta%22">Geochimica et Cosmochimica Acta</searchLink>. Oct2014, Vol. 142, p299-313. 15p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Iron%22">Iron</searchLink><br /><searchLink fieldCode="DE" term="%22X-ray+absorption%22">X-ray absorption</searchLink><br /><searchLink fieldCode="DE" term="%22Chromium+isotopes%22">Chromium isotopes</searchLink><br /><searchLink fieldCode="DE" term="%22Groundwater+analysis%22">Groundwater analysis</searchLink><br /><searchLink fieldCode="DE" term="%22Geochemistry%22">Geochemistry</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: A series of replicate flow-through cell experiments was conducted to characterize Cr isotope fractionation during Cr(VI) treatment by granular zero-valent iron (ZVI). Synthetic groundwater containing 50 mg L −1 Cr(VI) was pumped upward through a custom-made cell packed with ZVI under anaerobic conditions. The geochemical evolution of the system was monitored using pH and redox measurements, while aqueous effluent samples were retained for analysis of cations and Cr isotopes. Real-time, in situ X-ray absorption near edge structure (XANES) spectroscopy collected via a Kapton® window in the cell provided additional information on the speciation of the reaction products. Increases in δ 53 Cr values corresponding to decreases in Cr(VI) concentration suggested the occurrence of redox processes. Spectroscopic results correlated well with the isotope data, indicating reduction of Cr(VI) to Cr(III). The isotope data did not appear to follow a single trend. A two-stage system was proposed to explain the complex isotope trend, where the rapid Cr removal was associated with very little fractionation ( ε = −0.2‰), whereas slower removal was associated with a greater degree of fractionation ( ε = −1.2‰ to −1.5‰). Reactive transport modeling was used to quantify distinct isotope fractionation values ( ε ), differentiated by a significant change in the Cr removal rate. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Geochimica et Cosmochimica Acta is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.gca.2014.07.031 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 15 StartPage: 299 Subjects: – SubjectFull: Iron Type: general – SubjectFull: X-ray absorption Type: general – SubjectFull: Chromium isotopes Type: general – SubjectFull: Groundwater analysis Type: general – SubjectFull: Geochemistry Type: general Titles: – TitleFull: Examination of Cr(VI) treatment by zero-valent iron using in situ, real-time X-ray absorption spectroscopy and Cr isotope measurements. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Jamieson-Hanes, Julia H. – PersonEntity: Name: NameFull: Lentz, Adam M. – PersonEntity: Name: NameFull: Amos, Richard T. – PersonEntity: Name: NameFull: Ptacek, Carol J. – PersonEntity: Name: NameFull: Blowes, David W. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 10 Text: Oct2014 Type: published Y: 2014 Identifiers: – Type: issn-print Value: 00167037 Numbering: – Type: volume Value: 142 Titles: – TitleFull: Geochimica et Cosmochimica Acta Type: main |
| ResultId | 1 |
