Naslov
The effect of various metal cations on the formation of iron oxides in a highly alkaline medium

Autori
Krehula, Stjepko ; Musić, Svetozar

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
The 31st International Conference on the Applications of the Mössbauer effect, Kobe, Japan, September 25th-30th, 2011, Programme & Abstracts / Yoshida, Yutaka ; Nishida, Tetsuaki - Kobe, 2011, 227-227

Skup
The 31st International Conference on the Applications of the Mössbauer effect (ICAME 2011)

Mjesto i datum
Kobe, Japan, 25.09.2011. - 30.09.2011

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
iron oxides; goethite; hematite; magnetite; Mössbauer spectroscopy

Sažetak
Natural and synthetic iron oxides may contain different amounts of various metal cations incorporated into their structure [1]. Such incorporation can modify some of the properties (magnetic, electrical, catalytic, adsorption, electrochemical, gas sensing, etc.) desired for commercial applications of iron oxides. The effect of the presence of various metal cations on the formation of iron oxides in a highly alkaline precipitation system was investigated using Mössbauer spectroscopy and other techniques. Uniform lath-like α-FeOOH particles precipitated in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH) were used as reference material [2]. Generally, the presence of varying amounts of metal cations in this precipitation system resulted in the following (Table I, Fig. 1): a) formation of α-FeOOH with incorporated metal cations (mainly at lower [Mn+]), characterized by changes in the unit-cell size and reduction in the hyperfine magnetic field (Fig. 2), often accompanied by changes in particle size and shape, b) formation of other iron oxides (α-Fe2O3 or ferrihydrite), ferrites (mainly at higher [Mn+]) or AgFeO2 (in the case of Ag+). In the case of platinum group metal cations (Ru3+, Rh3+, Pd2+, Ir3+ and Pt4+) longer autoclaving (24 hours) led to the reduction of cations to the metallic state (formation of platinum group metal nanoparticles) followed by the reduction of iron(III) oxides to magnetite, Fe3O4.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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