In Situ Redox Flexibility of FeII-IIIOxyhydroxycarbonate Green Rust and Fougerite

2006 ◽  
Vol 40 (15) ◽  
pp. 4696-4702 ◽  
Author(s):  
Christian Ruby ◽  
Chandan Upadhyay ◽  
Antoine Géhin ◽  
Georges Ona-Nguema ◽  
Jean-Marie R. GÉnin
Keyword(s):  
Green Rust

Green rust as a precursor for magnetite: an in situ synchrotron based study

2008 ◽  
Vol 72 (1) ◽  
pp. 201-204 ◽  
Author(s):  
A. Sumoondur ◽  
S. Shaw ◽  
I. Ahmed ◽  
L. G. Benning
Keyword(s):  
Direct Evidence ◽  
Green Rust ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Subsequent Transformation ◽  
Rapid Formation ◽  
Reaction Proceeds

AbstractIn this study, direct evidence for the formation of magnetite via a green rust intermediate is reported. The Fe(II) induced transformation of ferrihydrite, was quantified in situ and under O2-free conditions using synchrotron-based time-resolved energy dispersive X-ray diffraction. At pH 9 and Fe(II)/Fe(III) ratios of 0.5 and 1, rapid growth (6 min) of sulphate green rust and its subsequent transformation to magnetite was observed. Electron microscopy confirmed these results, showing the initial rapid formation of hexagonal sulphate green rust particles, followed by the corrosion of the green rust as magnetite growth occurred, indicating that the reaction proceeds via a dissolution-reprecipitation mechanism. At pH 7 and Fe(II)/Fe(III) ratio of 0.5, sulphate green rust was the stable phase, with no transformation to magnetite.

scholarly journals Removal of Arsenate and Arsenite in Equimolar Ferrous and Ferric Sulfate Solutions through Mineral Coprecipitation: Formation of Sulfate Green Rust, Goethite, and Lepidocrocite

Soil Systems ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 68
Author(s):  
Chunming Su ◽  
Richard T. Wilkin
Keyword(s):  
Amorphous Solid ◽  
Arsenic Species ◽  
Green Rust ◽  
Geochemical Process ◽  
Batch Tests ◽  
Sulfate Solutions ◽  
Mineral Phases ◽  
Groundwater Systems ◽  
Solid Phases

An improved understanding of in situ mineralization in the presence of dissolved arsenic and both ferrous and ferric iron is necessary because it is an important geochemical process in the fate and transformation of arsenic and iron in groundwater systems. This work aimed at evaluating mineral phases that could form and the related transformation of arsenic species during coprecipitation. We conducted batch tests to precipitate ferrous (133 mM) and ferric (133 mM) ions in sulfate (533 mM) solutions spiked with As (0–100 mM As(V) or As(III)) and titrated with solid NaOH (400 mM). Goethite and lepidocrocite were formed at 0.5–5 mM As(V) or As(III). Only lepidocrocite formed at 10 mM As(III). Only goethite formed in the absence of added As(V) or As(III). Iron (II, III) hydroxysulfate green rust (sulfate green rust or SGR) was formed at 50 mM As(III) at an equilibrium pH of 6.34. X-ray analysis indicated that amorphous solid products were formed at 10–100 mM As(V) or 100 mM As(III). The batch tests showed that As removal ranged from 98.65–100%. Total arsenic concentrations in the formed solid phases increased with the initial solution arsenic concentrations ranging from 1.85–20.7 g kg−1. Substantial oxidation of initially added As(III) to As(V) occurred, whereas As(V) reduction did not occur. This study demonstrates that concentrations and species of arsenic in the parent solution influence the mineralogy of coprecipitated solid phases, which in turn affects As redox transformations.

Formation of Green Rust Sulfate: A Combined in Situ Time-Resolved X-ray Scattering and Electrochemical Study

Langmuir ◽  
2010 ◽  
Vol 26 (9) ◽  
pp. 6593-6603 ◽  
Author(s):  
Imad A. M. Ahmed ◽  
Liane G. Benning ◽  
Gabriella Kakonyi ◽  
Aryani D. Sumoondur ◽  
Nick J. Terrill ◽  
...  
Keyword(s):  
Green Rust ◽  
Electrochemical Study ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals In situ Measurements of X-ray Absorption Spectra during Transformation of Green Rust to Ferric Oxyhydroxide Via Aqueous Solution

2014 ◽  
Vol 54 (1) ◽  
pp. 125-130 ◽  
Author(s):  
Shun Fujieda ◽  
Aya Yoshino ◽  
Kozo Shinoda ◽  
Yohei Takahashi ◽  
Shigeru Suzuki
Keyword(s):  
Aqueous Solution ◽  
Absorption Spectra ◽  
In Situ Measurements ◽  
Green Rust ◽  
X Ray ◽  
Ferric Oxyhydroxide ◽  
X Ray Absorption

scholarly journals Green Rust: Revealing the Structural Evolution of Green Rust Synthesized in Ionic Liquids by In Situ Molecular Imaging (Adv. Mater. Interfaces 15/2020)

2020 ◽  
Vol 7 (15) ◽  
pp. 2070086
Author(s):  
Yanjie Shen ◽  
Yao Fu ◽  
Jennifer Yao ◽  
David Lao ◽  
Satish Nune ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Molecular Imaging ◽  
Structural Evolution ◽  
Green Rust

scholarly journals Oxidation modes and thermodynamics of FeII–III oxyhydroxycarbonate green rust: Dissolution–precipitation versus in situ deprotonation

2010 ◽  
Vol 74 (3) ◽  
pp. 953-966 ◽  
Author(s):  
Christian Ruby ◽  
Mustapha Abdelmoula ◽  
Sébastien Naille ◽  
Aurélien Renard ◽  
Varsha Khare ◽  
...  
Keyword(s):  
Green Rust ◽  
Oxidation Modes

Revealing the Structural Evolution of Green Rust Synthesized in Ionic Liquids by In Situ Molecular Imaging

2020 ◽  
Vol 7 (15) ◽  
pp. 2000452
Author(s):  
Yanjie Shen ◽  
Yao Fu ◽  
Jennifer Yao ◽  
David Lao ◽  
Satish Nune ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Molecular Imaging ◽  
Structural Evolution ◽  
Green Rust

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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