Gotić, Marijan; Musić, Svetozar; Popović, Stanko; Sekovanić, Lavoslav
Investigation of Factors Influencing the Precipitation of Iron Oxides from Fe(II) Containing Solutions.
Croatica Chemica Acta, 81
Factors that influence the precipitation of iron oxides from Fe(II) containing solutions were investigated by X-ray powder diffraction, (57)Fe Mossbauer and FT-IR spectroscopies, FE SEM and EDS techniques. Near spherical aggregates of spindle-shape goethite particles were obtained by oxidation of 0.1 mol dm(-3) FeSO(4) solution (suspension) with pure oxygen at 90 degrees C. Wide and thin goethite particles elongated along the crystallographic c-axis were formed in parallel. With the addition of tetramethylammonium hydroxide to 0.1 mol dm(-3) FeSO(4) solution (suspension) substoichiometric magnetite (Fe(3-x)O(4)) particles were additionally formed. They were dominant at pH > 12.5. Mossbauer spectroscopy was used to calculate the stoichiometries of Fe(3-x)O(4) particles. Very small magnetite particles (approximate to 20-100 nm) showed a tendency to aggregate. The twinning effect of octahedral magnetite particles (> 200 nm) was observed. A drastic effect on the properties of iron oxide precipitates was achieved by adding H(3)PO(4) to the precipitation system containing 0.1 mol dm(-3) FeSO(4) + 0.01 mol dm(-3) H(2)SO(4) solution at the start, In dependence on the concentration of the added H(3)PO(4). nanosize goethite particles about 15-25 nm in size, or poor crystalline ferrihydrite particles (two-line ferrihydrite) were obtained. The EDS analyses of the precipitates did not show any significant change in the sulphur content, whereas the phosphorous content gradually increased in the precipitates with an increase in the added H(3)PO(4). In high concentrations phosphates completely suppressed the formation of goethite under given experimental conditions, and phosphated ferrihydrite was formed instead.
||ferrihydrite; magnetite; phosphate; Mossbauer; FE SEM; x-ray-diffraction; mossbauer-spectroscopy; feso4 solution; fe-57 mossbauer; ft-ir; phosphate; goethite; hydrolysis; adsorption; hematite
||NATURAL SCIENCES > Chemistry
||Division of Materials Chemistry
|Project title||Project leader||Project code||Project type|
|Sinteza i mikrostruktura metalnih oksida i oksidnih stakala|| Mira Ristić||098-0982904-2952||MZOS|
|Struktura i svojstva posebnih nanomaterijala dobivenih suvremenim tehnikama|| Antun Tonejc||119-0982886-1009||MZOS|
||22 Oct 2013 11:02
||12 Feb 2014 11:33
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