Cation Exchange in Kaolinite-Iron Oxide Systems*

Formation of iron oxide nanoparticles within the internal cages of Na–Y zeolites was investigated. Sodium ions within the zeolites were replaced with iron(II) ions. Elemental composition studies showed a significant amount of iron in the exchanged sample. NaOH and dropwise additions of H2O2 at 60 °C triggered formation of zeolite–iron oxide systems. X-ray diffraction (XRD) patterns showed diminishing zeolite peaks along with evolution of peaks corresponding to γ-Fe2O3 and α-Fe2O3 with increasing NaOH concentration. Morphological changes from hexagonal-shaped zeolite to clusters of fine particles were observed under scanning electron microscope. Particles with about 15-nm diameter were detected by transmission electron microscopy. γ-Fe2O3 crystallites of 13.4 nm were determined from the broadening of XRD peaks. The magnetization curves of samples (precipitated using NaOH with concentrations of 2.0 M and above) showed absence of hysteresis and passed through the origin, indicating the particles are superparamagnetic. Gas adsorption–desorption measurement of the system precipitated with 2.0 M NaOH revealed a 26% increase in its specific surface area, indicating the presence of nanometer-sized particles within the zeolites.

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Microstructure of Rapidly Quenched Bismuth Iron Oxide Systems with Ferromagnetic Character

Japanese Journal of Applied Physics ◽

10.1143/jjap.30.l2095 ◽

1991 ◽

Vol 30 (Part 2, No. 12B) ◽

pp. L2095-L2097 ◽

Cited By ~ 8

Author(s):

Katsuhisa Tanaka ◽

Kazuyuki Hirao ◽

Naohiro Soga ◽

Hirotaro Mori

Keyword(s):

Iron Oxide ◽

Bismuth Iron Oxide ◽

Oxide Systems ◽

Ferromagnetic Character

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Chitosan-Derived Iron Oxide Systems for Magnetically Guided and Efficient Water Purification Processes from Polycyclic Aromatic Hydrocarbons

ACS Sustainable Chemistry & Engineering ◽

10.1021/acssuschemeng.6b02126 ◽

2016 ◽

Vol 5 (1) ◽

pp. 793-801 ◽

Cited By ~ 39

Author(s):

Roberto Nisticò ◽

Flavia Franzoso ◽

Federico Cesano ◽

Domenica Scarano ◽

Giuliana Magnacca ◽

...

Keyword(s):

Polycyclic Aromatic Hydrocarbons ◽

Iron Oxide ◽

Aromatic Hydrocarbons ◽

Water Purification ◽

Oxide Systems ◽

Polycyclic Aromatic

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Study of the Formation of CaO-3FeO-Fe2O3 in Iron Oxide Systems / Untersuchungen zur CaO-3FeO-Fe2O3-Bildung in Eisenoxid-Systemen

Practical Metallography ◽

10.1515/pm-1991-280206 ◽

1991 ◽

Vol 28 (2) ◽

pp. 83-87

Author(s):

Eguakhide P. Oaikhinan

Keyword(s):

Iron Oxide ◽

Oxide Systems

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Interactions in Sulphur Oxide-Iron Oxide Systems

Journal of Engineering for Power ◽

10.1115/1.3616670 ◽

1967 ◽

Vol 89 (2) ◽

pp. 297-303 ◽

Cited By ~ 3

Author(s):

A. Levy ◽

E. L. Merryman

Keyword(s):

Iron Oxide ◽

Protective Effect ◽

Gas Mixtures ◽

Oxide Systems ◽

Sulphur Oxide

Fe2O3-, Fe3O4-, NaOH-Fe2O3-, and NaOH-Fe3O4-coated substrates of Vycor and of iron were exposed to controlled gas mixtures containing SO2 and SO3. Sulfate and sulfide formation are examined and explained on thermodynamic grounds. Examination of the role of MgO coatings indicates a limited “protective” effect through its removal of SO3 from the gas stream.

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Magnetic characterisation of magnetite and hematite from the Blötberget apatite – iron oxide deposits (Bergslagen), south-central Sweden

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2018-0183 ◽

2019 ◽

Vol 56 (9) ◽

pp. 948-957 ◽

Cited By ~ 2

Author(s):

Bjarne S.G. Almqvist ◽

Andreas Björk ◽

Hannes B. Mattsson ◽

Daniel Hedlund ◽

Klas Gunnarsson ◽

...

Keyword(s):

Magnetic Properties ◽

Magnetic Susceptibility ◽

Iron Oxide ◽

Inductively Coupled Plasma ◽

Magnetic Measurements ◽

Core Material ◽

Morin Transition ◽

Oxide Systems ◽

Weight Percentage ◽

South Central

Rock magnetic measurements were carried out on drill core material and hand specimens from the Blötberget apatite – iron oxide deposit in the Bergslagen ore province, south-central Sweden, to characterise their magnetic properties. Measurements included several kinds of magnetic susceptibility and hysteresis parameters. Petrographic and scanning electron microscopy were used to independently identify and quantify the amount and type of magnetite and hematite. Two hematite-rich samples were studied with laser ablation inductively coupled plasma mass spectrometry to quantify the trace element chemistry in hematite and investigate the potential influence of trace elements on magnetic properties. Three aspects of this study are noteworthy. (1) Hematite-rich samples display strong anisotropy of magnetic susceptibility, which is likely to affect the appearance and modelling of magnetic anomalies. (2) The magnitude-drop in susceptibility across Curie and Néel temperature transitions shows significant correlation with the respective weight percentage of magnetite and hematite. Temperature-dependent magnetic susceptibility measurements can therefore be used to infer the amounts of both magnetite and hematite. (3) Observations of a strongly depressed Morin transition at approximately −60 to −70 °C (200 to 210 K) are made during low-temperature susceptibility measurements. This anomalous Morin transition is most likely related to trace amounts of V and Ti that substitute for Fe in the hematite. When taken together, these magnetic observations improve the understanding of the magnetic anomaly signature of the Blötberget apatite – iron oxide deposits and may potentially be utilised in a broader context when assessing similar (Paleoproterozoic) apatite – iron oxide systems.

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