Next Article in Journal / Special Issue
Hot Spots and Hot Moments of Soil Moisture Explain Fluctuations in Iron and Carbon Cycling in a Humid Tropical Forest Soil
Previous Article in Journal
Assessment of Soil Fertility under Different Land-Use Systems in Dhading District of Nepal
Previous Article in Special Issue
Arsenite Depletion by Manganese Oxides: A Case Study on the Limitations of Observed First Order Rate Constants
Article

Products of Hexavalent Chromium Reduction by Green Rust Sodium Sulfate and Associated Reaction Mechanisms

1
Institute for Applied Geosciences, Karlsruhe Institute of Technology, Adenauerring 20b, Building 50.40, 76135 Karlsruhe, Germany
2
Institute for Synchrotron Radiation, Karlsruhe Institute of Technology, Herman-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
3
GFZ German Research Center for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
4
Department of Earth Sciences, Free University of Berlin, 12249 Berlin, Germany
5
Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
6
Department of Applied Geosciences, Technical University of Berlin, Ernst-Reuter-Platz 1, 10587 Berlin, Germany
*
Author to whom correspondence should be addressed.
Current address: School of Chemical and Process Engineering, University of Leeds, Leeds LS29JT, UK.
Soil Syst. 2018, 2(4), 58; https://doi.org/10.3390/soilsystems2040058
Received: 28 September 2018 / Revised: 12 October 2018 / Accepted: 25 October 2018 / Published: 29 October 2018
(This article belongs to the Special Issue Iron and Manganese Biogeochemical Cycling in Soils)
The efficacy of in vitro Cr(VI) reduction by green rust sulfate suggests that this mineral is potentially useful for remediation of Cr-contaminated groundwater. Previous investigations studied this reaction but did not sufficiently characterize the intermediates and end products at chromate (CrO42−) concentrations typical of contaminant plumes, hindering identification of the dominant reaction mechanisms under these conditions. In this study, batch reactions at varying chromate concentrations and suspension densities were performed and the intermediate and final products of this reaction were analyzed using X-ray absorption spectroscopy and electron microscopy. This reaction produces particles that maintain the initial hexagonal morphology of green rust but have been topotactically transformed into a poorly crystalline Fe(III) oxyhydroxysulfate and are coated by a Cr (oxy) hydroxide layer that results from chromate reduction at the surface. Recent studies of the behavior of Cr(III) (oxy) hydroxides in soils have revealed that reductive transformation of CrO42− is reversible in the presence of Mn(IV) oxides, limiting the applicability of green rust for Cr remediation in some soils. The linkage of Cr redox speciation to existing Fe and Mn biogeochemical cycles in soils implies that modification of green rust particles to produce an insoluble, Cr(III)-bearing Fe oxide product may increase the efficacy of this technique. View Full-Text
Keywords: green rust sulfate; chromium; EXAFS; metal redox cycles green rust sulfate; chromium; EXAFS; metal redox cycles
Show Figures

Figure 1

MDPI and ACS Style

N. Thomas, A.; Eiche, E.; Göttlicher, J.; Steininger, R.; G. Benning, L.; M. Freeman, H.; Dideriksen, K.; Neumann, T. Products of Hexavalent Chromium Reduction by Green Rust Sodium Sulfate and Associated Reaction Mechanisms. Soil Syst. 2018, 2, 58. https://doi.org/10.3390/soilsystems2040058

AMA Style

N. Thomas A, Eiche E, Göttlicher J, Steininger R, G. Benning L, M. Freeman H, Dideriksen K, Neumann T. Products of Hexavalent Chromium Reduction by Green Rust Sodium Sulfate and Associated Reaction Mechanisms. Soil Systems. 2018; 2(4):58. https://doi.org/10.3390/soilsystems2040058

Chicago/Turabian Style

N. Thomas, Andrew; Eiche, Elisabeth; Göttlicher, Jörg; Steininger, Ralph; G. Benning, Liane; M. Freeman, Helen; Dideriksen, Knud; Neumann, Thomas. 2018. "Products of Hexavalent Chromium Reduction by Green Rust Sodium Sulfate and Associated Reaction Mechanisms" Soil Syst. 2, no. 4: 58. https://doi.org/10.3390/soilsystems2040058

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop