Journal ArticleDOI
Reduction and Oxidation of Fe3+ in Dioctahedral Smectites—2: Reduction with Sodium Sulphide Solutions
I. Rozenson,L. Heller-Kallai +1 more
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In this article, the difference between Na2S and other reducing agents is discussed, which are attributed to the high concentration of Fe-OH-Fe groups in nontronite which are unstable on reduction.Abstract:
Reaction with Na2S solutions at high pH led to almost complete, reversible reduction of iron in montmorillonite, whereas the structural iron of nontronite persisted in the ferric form. Concentrated Na2S solutions caused severe corrosion of nontronite and extracted appreciable amounts of iron, which was precipitated as sulphides. In contrast the morphology of montmorillonite was preserved and only very minor amounts of iron were extracted. These differences were attributed to the high concentration of Fe-OH-Fe groups in nontronite, which are unstable on reduction. The difference between Na2S and other reducing agents is discussed.read more
Citations
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Hydrophobicity of siloxane surfaces in smectites as revealed by aromatic hydrocarbon adsorption from water
William F. Jaynes,Stephen Boyd +1 more
TL;DR: In this article, the authors measured the adsorption of aromatic hydrocarbons from water by organo-clays and found that the planar surfaces of the compounds adsorb directly to the clay surface.
Journal ArticleDOI
The chemistry of hydrothermal mounds near the Galapagos Rift
TL;DR: Samples dredged from the sediment mounds have a unique chemistry and mineralogy which reveals details of the hydrothermal processes that produce these deposits as discussed by the authors, where the mounds form primarily by deposition of Fe, Mn and Si from hydrotherm fluids which circulate through the basalt crust and the overlying sediments.
Journal ArticleDOI
Pyritization processes and greigite formation in the advancing sulfidization front in the upper Pleistocene sediments of the Black Sea
Lev N. Neretin,Michael E. Böttcher,Bo Barker Jørgensen,Igor I Volkov,Holger Lüschen,Katharina Hilgenfeldt +5 more
TL;DR: In this paper, two processes of diffusion-limited pyrite formation were identified, i.e., precipitation with the accumulation of iron sulfide precursors with the average chemical composition of FeSn (n = 1.10−1.29), including greigite.
Journal ArticleDOI
Effects of reduction and reoxidation of structural iron on the surface charge and dissolution of dioctahedral smectites
TL;DR: In this paper, the effect of Fe oxidation state on the surface charge and solubility of smectites were studied using the <2-t~m, Na+-saturated fraction of an Upton, Wyoming; a Czechoslovakian; and a New Zealand montmorillonite.
Journal ArticleDOI
The use of mössbauer spectroscopy of iron in clay mineralogy
L. Heller-Kallai,I. Rozenson +1 more
References
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Journal ArticleDOI
Reduction and Oxidation of Fe3+ in Dioctahedral Smectites — 1: Reduction with Hydrazine and Dithionite
I. Rozenson,L. Heller-Kallai +1 more
TL;DR: In this article, the results obtained by different physical methods of investigation suggest that reduction of iron is associated with protonation of an adjacent OH group, but the structural changes occurring on reduction are reversible only when Al-OH-Fe, but not when Fe- OH-Fe associations are involved.
Journal ArticleDOI
Mössbauer studies of iron sulphides
TL;DR: The Mossbauer spectra of pyrite, marcasite, pyrrhotite, greigite and mackinawite have been taken at room temperature.
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Reduction and Oxidation of Fe3+ in Dioctahedral Smectites — 1: Reduction with Hydrazine and Dithionite
I. Rozenson,L. Heller-Kallai +1 more