Electron-microscopic investigation of the formation of colloidal beta FeOOH during slow hydrolysis of an aqueous ferric chloride solution at room temperature

Wolf, R. H. H.; Wrischer, Mercedes; Šipalo-Žuljević, Josip

doi:10.1007/bf01500482

Cited by 25 publications

(9 citation statements)

References 11 publications

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“…600°C in the products at Cu/Fe у 0. 01 2 show similar SO 4 2Ϫ content, being indicative of the similar morphology, pore structure, and crystallinity of the particles. From this result we can deduce that the particles formed with metal sulfates are produced by an assembly of small primary particles with a nearly constant size, and the particles formed with Ti͑SO 4 ) 2 are made from smaller primary particles.…”

Section: Resultsmentioning

confidence: 73%

Influences of Metal Chlorides and Sulfates on the Formation of Beta-FeOOH Particles by Aerial Oxidation of FeCl[sub 2] Solutions

Ishikawa

Isa

Kandori

et al. 2004

J. Electrochem. Soc.

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To investigate the influences of metal ions on ␤-FeOOH formation, the ␤-FeOOH particles were prepared by aerial oxidation of FeCl 2 solutions in the presence of chlorides and sulfates of Ti͑IV͒, Fe͑III͒, Cu͑II͒, and Ni͑II͒, and CrCl 3 at different metal/Fe atomic ratios of 0-0.1 and characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, inductively coupled plasma, thermogravimetry and differential thermal analysis, and N 2 adsorption. The produced particles contained a large quantity of Ti͑IV͒ and Cr͑III͒ but little Cu͑II͒ and Ni͑II͒. All the added metal chlorides and sulfates made the formed particles less crystalline. The sulfate and chloride of Ti͑IV͒ inhibited the formation of ␤-FeOOH at a high Ti/Fe by a marked depression of solution pH by hydrolysis of Ti͑IV͒. The metal sulfate ions effectively reduced the crystallinty of ␤-FeOOH to give highly microporous particles. The strong inhibitory effect of SO 4 2Ϫ on the crystallization of ␤-FeOOH can be ascribed to the adsorption of SO 4 2Ϫ on the primary particles. This is also evident from the high content of SO 4 2Ϫ in the formed particles.

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Section: Resultsmentioning

confidence: 73%

Influences of Metal Chlorides and Sulfates on the Formation of Beta-FeOOH Particles by Aerial Oxidation of FeCl[sub 2] Solutions

Ishikawa

Isa

Kandori

et al. 2004

J. Electrochem. Soc.

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“…An amount equal to ~ 5~o of the expected final mass of FeOOH was used. Other preparations of fl-FeOOH, having the larger spindle shaped crystal morphology (Gallagher, 1970;Mackay, 1960;Soderquist and Jansson, 1966;Wolf et al, 1967), were made from dilute iron(Ill) chloride solutions (0.04 M) without added base which was allowed to stand at 65~ (10 days) or room temperature (3 months). Other details, and methods used for XRD, electron microscopy and electron diffraction, are given by Atkinson et al (1968).…”

Section: Methodsmentioning

confidence: 99%

“…Akaganeite (fl-FeOOH) is formed from aqueous iron(III) chloride solutions, under a wide range of conditions of hydrolysis, including dilute or concentrated solutions, with base additions ranging from zero up to OH/Fe mole ratio about 2.8, at room temperature or at elevated temperatures (Feitknecht and Michaelis, 1962;Fordham, 1970;Knight and Sylva, 1974;Mackay, 1960;Murphy et al, 1975;Soderquist and Jansson, 1966;Wolf et al, 1967).…”

Section: Introductionmentioning

confidence: 99%

Crystal Nucleation and Growth in Hydrolysing Iron(III) Chloride Solutions

Atkinson

1977

Clays and clay miner.

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S.5 molal iron(ilI) chloride solutions were hydrolysed at room temperature by base additions in the range OH/Fe mole ratio (~2.75. After an ageing period the hydrolysed solutions were used to produce amorphous hydroxide gels from which crystalline products were grown at 65~ at low pH or high pH. Examination of crystal composition and morphology and comparison with similarly treated nitrate solutions showed that the nucleation of hematite and goethite is inhibited in chloride containing solutions, which allow growth of small rod shaped fl-FeOOH to predominate or occur exclusively in gels at pH 1 2. The addition of seed crystals of hematite and goethite allows competitive growth of all three minerals. The transformations fl-FeOOH ~ a-Fe203 and fl-FeOOH ~ a-FeOOH at pH 1-2 proceed by dissolution and reprecipitation and are promoted by adding seed crystals.

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“…For all Fe 3+ to be reduced to Fe 2+ , the discharge time should be 37.5 h. The difference in discharge time indicates that not all of the assumed Fe 3+ has been converted into Fe 2+ under the experimental conditions, which can be accounted for by the incomplete ionization of Fe 3+ caused by the formation of colloidal b-FeOOH through the slow hydrolysis in dilute FeCl 3 aqueous solutions at room temperature. [17,18] The discharge curves at various current densities are shown in Figure 2 b. The linear decrease in the cell voltage in response to an increase in the discharge current density, see the inset, suggests that the drop in the cell voltage was caused predomi-nantly by its internal resistance which, in this case, comes from the LISICON plate that has a Li + -ion conductivity only on the order of 10 À4 S cm À1 , as well as from the dilute aqueous FeCl 3 solution, that also has a relatively low ionic conductivity.…”

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confidence: 99%