Biogeochemical redox processes of sulfide minerals

2007 ◽  
pp. 95-119
Author(s):  
D.J. Vaughan ◽  
V.S. Coker
Keyword(s):  
Sulfide Minerals ◽  
Redox Processes

Effect of surfactants and their mixtures on wettability of sulfide minerals by molten sulfur

2019 ◽  
Author(s):  
El'vira Kolmachikhina ◽  
◽  
Ekaterina Ryzhkova ◽  
Dar'ya Dmitrieva ◽  
◽  
...  
Keyword(s):  
Sulfide Minerals ◽  
Molten Sulfur

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

An Excel Workbook for Identifying Redox Processes in Ground Water

2009 ◽  
Author(s):  
Bryant C. Jurgens ◽  
Peter B. McMahon ◽  
Francis H. Chapelle ◽  
Sandra M. Eberts
Keyword(s):  
Ground Water ◽  
Redox Processes

Abiotic reduction of 2,4-dinitrotoluene in the presence of sulfide minerals under anoxic conditions

1996 ◽  
Vol 34 (10) ◽  
pp. 25-33 ◽  
Author(s):  
Cheng Jiayang ◽  
Makram T. Suidan ◽  
Albert D. Venosa
Keyword(s):  
Electron Donor ◽  
Chemical Reduction ◽  
Sulfide Minerals ◽  
Sulfide Concentration ◽  
Magnesium Ions ◽  
High Concentration ◽  
Anoxic Conditions ◽  
High Affinity ◽  
Iron Nickel ◽  
Abiotic Reduction

Abiotic reduction of 2,4-dinitrotoluene (DNT) in the presence of sulfide minerals has been investigated under anoxic conditions at 35°C. 2,4-DNT was abiotically reduced to 4-amino-2-nitrotoluene (4-A-2-NT) and 2-amino-4-nitrotoluene (2-A-4-NT) in the presence of high concentration of sulfide (0.84 mM). No abiotic reduction of 2,4-DNT was observed in the presence of low sulfide concentration (0.42 mM). The rate and the extent of the abiotic reduction of 2,4-DNT were increased with an increase in sulfide concentration. Sulfide served as an electron donor for the reduction of 2,4-DNT. The 2-nitro group was preferentially reduced, making the 2-A-4-NT:4-A-2-NT ratio in the final products 2:1. The addition of iron, nickel, and cobalt minerals significantly enhanced the abiotic reduction. The FeS, NiS, and CoS solids formed in the serum bottles catalyzed the reduction of 2,4-DNT preferentially to 4-A-2-NT. MnS and CuS solids also catalyzed the reduction of 2,4-DNT to 4-A-2-NT, but did not change the overall reduction of 2,4-DNT. However, the presence of calcium, zinc, and magnesium minerals impeded 2,4-DNT reduction. The calcium, zinc, and magnesium ions have a high affinity to sulfide, inactivating sulfide as an electron donor for the chemical reduction of 2,4-DNT.

The Effect of Complexing Reagents on Flotation of Sulfide Minerals and Cassiterite from Tin-Sulfide Tailings

2020 ◽  
pp. 1-14
Author(s):  
T.N. Matveeva ◽  
V.A. Chanturiya ◽  
V.V. Getman ◽  
N.K. Gromova ◽  
M.V. Ryazantseva ◽  
...  
Keyword(s):  
Sulfide Minerals ◽  
Tin Sulfide ◽  
Sulfide Tailings

New potential pyrrhotite and pentlandite reference materials for sulfur and iron isotope microanalysis

2021 ◽  
Author(s):  
Lei Chen ◽  
Yu Liu ◽  
Yang Li ◽  
Qiuli Li ◽  
Xian-Hua Li
Keyword(s):  
Reference Materials ◽  
Sulfide Minerals ◽  
Ore Deposits ◽  
Iron Isotope ◽  
S Isotopes ◽  
Fe Isotopes

Pyrrhotite and pentlandite are the most common Fe sulfide minerals in magmatic ore deposits and meteorites. Multiple S isotopes pairing with Fe isotopes of bulk Fe sulfides have proven to...

Sign in / Sign up

Export Citation Format

Share Document