Naslov
Precipitation from Fe(ClO4)3 solutions by slow or forced hydrolysis

Autori
Ristić, Mira ; Musić, Svetozar ; Godec, Matjaž

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

Izvornik
Book of Abstracts of the Fourteenth Croatian-Slovenian Crystallographic Meeting / Popović, Stanko ; Leban, Ivan - Zagreb : Hrvatska kristalografska zajednica HAZU, 2005, 30-30

Skup
Fourteenth Croatian-Slovenian Crystallographic Meeting

Mjesto i datum
Vrsar, Hrvatska, 2005

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
FeOOH; Fe2O3; FT-IR; Mossbauer; FE SEM; TEM

Sažetak
Hydrolysis of Fe3+ ions plays an important role in natural processes, corrosion of iron (steel), synthesis of Fe(III)-oxyhydroxides and oxides, as well as in the synthesis of many Fe-bearing materials for advanced technologies. The kinetics of the Fe3+ hydrolysis in aqueous solutions and the properties of solid hydrolytic products strongly depend on the nature of anion involved. Majority of studies was related to the hydrolysis of FeCl3, Fe(NO3)3 or Fe2(SO4)3 salt solutions, whereas a much smaller number was related to the Fe(ClO4)3 hydrolysis. In the present work, we have focused on the properties of precipitates formed by slow and forced hydrolyses of Fe(ClO4)3 aqueous solutions. Phase compositions of the precipitates were determined using 57Fe Mössbauer and FT-IR spectroscopies. Size and shape of particles were investigated by FE SEM and TEM techniques. Slow hydrolysis of 5&middot ; 10-3 M Fe(ClO4)3 solution at RT yielded g-FeOOH. A mixture of g-FeOOH as a dominant phase and a-FeOOH as minor phase was obtained by slow hydrolysis of 1&middot ; 10-2 M Fe(ClO4)3 solution. Forced hydrolysis of the 0.1 M Fe(ClO4)3 + 0.1 M HClO4 solution at 90 oC yielded a-Fe2O3. A FE SEM investigation showed that obtained a-Fe2O3 particles have a layered substructure. High uniformity of these particles was achieved. a-Fe2O3 particles of different size and shape were obtained by forced hydrolysis of 0.1 M Fe(ClO4)3 + 0.1 M HClO4 solution at 160 oC. On the other hand the forced hydrolysis of 0.1 M Fe(ClO4)3 solutions (without HClO4 addition) at 160 oC yielded nanosized a-Fe2O3 particles with size varying between ~ 15 and ~ 60 nm. Forced hydrolysis of Fe(ClO4)3 solutions in the presence of sodium dodecyl sulphate yielded a-FeOOH as a single phase. Mössbauer spectra showed superparamagnetic nature of these a-FeOOH particles.

Izvorni jezik
Engleski

POVEZANOST RADA