Chromium isotope fractionation factors for reduction of Cr(VI) by aqueous Fe(II) and organic molecules | |
Jacquelyn W. Kitchen; Thomas M. Johnson; Thomas D. Bullen; Jianming Zhu; Amanda Raddatz | |
2012 | |
Source Publication | Geochimica et Cosmochimica Acta
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Volume | 89Pages:190-201 |
Abstract | Chromium stable isotope ratios are useful as indicators of Cr redox reactions and Cr sources in both modern and ancient geochemical systems. Correct interpretation of Cr isotope data requires a quantitative understanding of isotopic fractionation by various processes, the most important of which is reduction of Cr(VI) to Cr(III). We determined the magnitude of isotopic fractionation, for the 53Cr/52Cr ratio, induced by abiotic, dark reduction of Cr(VI) by aqueous Fe(II) and a few organic substances. The isotopic fractionation for reduction by dissolved Fe(II), expressed as ε(≈δ53Crproduct flux − δ53Crreactant) is −4.20 ± 0.11‰ from pH = 4.0 to 5.3. Lesser fractionation was observed in preliminary experiments with very rapid reaction; we attribute this to transient heterogeneity and diffusive limitation of the reaction as reactants were mixed. This phenomenon is a general problem with batch isotopic fractionation experiments, if significant reaction occurs before mixing of reactants is complete. ε = −3.11 ± 0.11‰ for reduction by three organic reductants (a humic acid at pH = 4.5 and 5.0, a fulvic acid at pH = 5.0, and mandelic acid catalyzed by goethite or γ-Al2O3 at pH = 4.0). |
Indexed By | SCI |
Language | 英语 |
Document Type | 期刊论文 |
Identifier | http://ir.gyig.ac.cn/handle/42920512-1/9470 |
Collection | 环境地球化学国家重点实验室 |
Affiliation | 1.Department of Geology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA 2.Water Resources Division, US Geological Survey, Menlo Park, CA 94025, USA 3.The State Key Lab of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China |
Recommended Citation GB/T 7714 | Jacquelyn W. Kitchen;Thomas M. Johnson;Thomas D. Bullen;Jianming Zhu;Amanda Raddatz. Chromium isotope fractionation factors for reduction of Cr(VI) by aqueous Fe(II) and organic molecules[J]. Geochimica et Cosmochimica Acta,2012,89:190-201. |
APA | Jacquelyn W. Kitchen;Thomas M. Johnson;Thomas D. Bullen;Jianming Zhu;Amanda Raddatz.(2012).Chromium isotope fractionation factors for reduction of Cr(VI) by aqueous Fe(II) and organic molecules.Geochimica et Cosmochimica Acta,89,190-201. |
MLA | Jacquelyn W. Kitchen;Thomas M. Johnson;Thomas D. Bullen;Jianming Zhu;Amanda Raddatz."Chromium isotope fractionation factors for reduction of Cr(VI) by aqueous Fe(II) and organic molecules".Geochimica et Cosmochimica Acta 89(2012):190-201. |
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Chromium isotope fra(531KB) | 期刊论文 | 作者接受稿 | 开放获取 | CC BY-NC-SA | View Application Full Text |
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