Step towards nanoscale Fe moieties

Intercalation of simple and Keggin-type iron-containing ions in-between the layers of Na-montmorillonite

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Abstract

The synthesis and characterization of iron-containing Na-montmorillonite prepared by various techniques are reported. Methods include ion exchange by Fe(II) ion and pillaring by partially hydrolysed Fe(II) salt or by Al13O7+40 where the substitution of Fe(III) for Al(III) was attempted. Substances were characterized by elemental analysis, thermogravimetry, X-ray diffractometry (XRD), 27Al and 29Si MAS NMR, FT-IR spectroscopies, and BET measurements. The coordination and oxidation states of iron were deduced from 57Fe Mössbauer spectra. Ion exchange resulted in the incorporation of polynuclear hydrous Fe(III) oxides characterized by octahedral coordination in significant amounts. In contradiction to earlier reports, we find no evidence for isomorphous substitution of iron for aluminium in Al13O7+40 Keggin ions. Instead, mixed pillars were formed containing Al13O7+40 Keggin ions and hydrous iron oxide oligomers. After reduction, large magnetite patches kept the layers apart when the partially hydrolysed pure iron salt was used for pillaring. Heat treatment influenced the water content of the intercalated species. The oxidation state of iron could be significantly influenced by reduction with hydrogen at various temperatures depending on the method of preparation.

Original languageEnglish
Pages (from-to)1067-1072
Number of pages6
JournalJournal of Physics and Chemistry of Solids
Volume57
Issue number6-8
Publication statusPublished - Jul 1996

Fingerprint

Bentonite
montmorillonite
Intercalation
Clay minerals
intercalation
Iron
Ions
iron
ions
Ion exchange
Substitution reactions
Salts
substitutes
Ferrosoferric Oxide
salts
Oxidation
oxidation
Magnetite
thermogravimetry
Aluminum

Keywords

  • A. oxides
  • B. chemical synthesis
  • C. X-ray diffraction
  • D. Mössbauer

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

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title = "Step towards nanoscale Fe moieties: Intercalation of simple and Keggin-type iron-containing ions in-between the layers of Na-montmorillonite",
abstract = "The synthesis and characterization of iron-containing Na-montmorillonite prepared by various techniques are reported. Methods include ion exchange by Fe(II) ion and pillaring by partially hydrolysed Fe(II) salt or by Al13O7+40 where the substitution of Fe(III) for Al(III) was attempted. Substances were characterized by elemental analysis, thermogravimetry, X-ray diffractometry (XRD), 27Al and 29Si MAS NMR, FT-IR spectroscopies, and BET measurements. The coordination and oxidation states of iron were deduced from 57Fe M{\"o}ssbauer spectra. Ion exchange resulted in the incorporation of polynuclear hydrous Fe(III) oxides characterized by octahedral coordination in significant amounts. In contradiction to earlier reports, we find no evidence for isomorphous substitution of iron for aluminium in Al13O7+40 Keggin ions. Instead, mixed pillars were formed containing Al13O7+40 Keggin ions and hydrous iron oxide oligomers. After reduction, large magnetite patches kept the layers apart when the partially hydrolysed pure iron salt was used for pillaring. Heat treatment influenced the water content of the intercalated species. The oxidation state of iron could be significantly influenced by reduction with hydrogen at various temperatures depending on the method of preparation.",
keywords = "A. oxides, B. chemical synthesis, C. X-ray diffraction, D. M{\"o}ssbauer",
author = "I. P{\'a}link{\'o} and K. L{\'a}z{\'a}r and I. Hannus and Imre Kirisci",
year = "1996",
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T1 - Step towards nanoscale Fe moieties

T2 - Intercalation of simple and Keggin-type iron-containing ions in-between the layers of Na-montmorillonite

AU - Pálinkó, I.

AU - Lázár, K.

AU - Hannus, I.

AU - Kirisci, Imre

PY - 1996/7

Y1 - 1996/7

N2 - The synthesis and characterization of iron-containing Na-montmorillonite prepared by various techniques are reported. Methods include ion exchange by Fe(II) ion and pillaring by partially hydrolysed Fe(II) salt or by Al13O7+40 where the substitution of Fe(III) for Al(III) was attempted. Substances were characterized by elemental analysis, thermogravimetry, X-ray diffractometry (XRD), 27Al and 29Si MAS NMR, FT-IR spectroscopies, and BET measurements. The coordination and oxidation states of iron were deduced from 57Fe Mössbauer spectra. Ion exchange resulted in the incorporation of polynuclear hydrous Fe(III) oxides characterized by octahedral coordination in significant amounts. In contradiction to earlier reports, we find no evidence for isomorphous substitution of iron for aluminium in Al13O7+40 Keggin ions. Instead, mixed pillars were formed containing Al13O7+40 Keggin ions and hydrous iron oxide oligomers. After reduction, large magnetite patches kept the layers apart when the partially hydrolysed pure iron salt was used for pillaring. Heat treatment influenced the water content of the intercalated species. The oxidation state of iron could be significantly influenced by reduction with hydrogen at various temperatures depending on the method of preparation.

AB - The synthesis and characterization of iron-containing Na-montmorillonite prepared by various techniques are reported. Methods include ion exchange by Fe(II) ion and pillaring by partially hydrolysed Fe(II) salt or by Al13O7+40 where the substitution of Fe(III) for Al(III) was attempted. Substances were characterized by elemental analysis, thermogravimetry, X-ray diffractometry (XRD), 27Al and 29Si MAS NMR, FT-IR spectroscopies, and BET measurements. The coordination and oxidation states of iron were deduced from 57Fe Mössbauer spectra. Ion exchange resulted in the incorporation of polynuclear hydrous Fe(III) oxides characterized by octahedral coordination in significant amounts. In contradiction to earlier reports, we find no evidence for isomorphous substitution of iron for aluminium in Al13O7+40 Keggin ions. Instead, mixed pillars were formed containing Al13O7+40 Keggin ions and hydrous iron oxide oligomers. After reduction, large magnetite patches kept the layers apart when the partially hydrolysed pure iron salt was used for pillaring. Heat treatment influenced the water content of the intercalated species. The oxidation state of iron could be significantly influenced by reduction with hydrogen at various temperatures depending on the method of preparation.

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