Mössbauer study of ferric hydroxides and hydroxo complexes and their bahaviour in alkaline electrolytes

Kamnev, Alexander A.; Ezhov, B. B.; Kopelev, N. S.; Kiselev, Yu. M.; Perfilyev, Yurii D.

doi:10.1016/0013-4686(91)80003-q

Cited by 17 publications

(6 citation statements)

References 14 publications

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“…For example, from Raman, 4,5 solution X-ray diffraction 6 and EXAFS 7 measurements it has been established that Al(III) and Ga(III) are predominantly four-fold coordinated even at the highest concentrations of base. 27 Al and 71 Ga NMR measurements support these findings as the observed variations in the NMR patterns were fully accounted for in terms of the formation of contact ion-pairs, 5,8 without the need to invoke even the existence of a six-fold coordinated species.…”

Section: Introductionmentioning

confidence: 56%

“…d Quick-freezing performed when the solid ferric-hydroxo complex salt had already started to precipitate from a solution identical to that used for preparing quick-frozen solution 1. e Identical IS value is reported for room temperature measurements in ref. 27.…”

Section: Mössbauer Spectra Of the Solid Ferric-hydroxo Complex Salt A...mentioning

confidence: 99%

“…The singlet in the M össbauer spectrum of the solid obtained (isomer shift is 0.68 ± 0.02 mm s -1 and 0.72 mm s -1 half width) indicated the presence of a 'symmetrically coordinated mononuclear hydroxo complex, statistically distributed in the NaOH•H 2 O matrix'. 27 Upon heating, the symmetry of the complex was retained and the observed increase in the line width was attributed to the non-uniformity of the complexes' environment due to non-uniform drying. 28 The colloidal and/or polynuclear complex (during a 3.5 years ageing period) was found to transform to a reddish-brown solid complex with M össbauer spectral parameters very similar to those of the solid obtained upon evaporation.…”

Section: Introductionmentioning

confidence: 98%

“…For example, a number of solid complexes either with [M(OH) 4 ]or with [M(OH) 6 ] 3-(M = Al(III) and Ga(III)) building blocks are known from the literature, 24-26 but in the solutions from which these complexes are obtained, neither [Al(OH) 6 ] 3nor [Ga(OH) 6 ] 3are present in experimentally detectable quantities. 5, 8 Kamnev et al made a remarkable effort [27][28][29] to elucidate the M össbauer spectrum of the Fe(III)-hydroxo complex species forming in strongly alkaline aqueous solutions. In concentrated (15-17 M) NaOH solution, ferric ions were found to form a reddishorange (supposedly colloidal and/or polynuclear) compound.…”

Section: Introductionmentioning

confidence: 99%

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The structure of Fe(iii) ions in strongly alkaline aqueous solutions from EXAFS and Mössbauer spectroscopy

et al. 2008

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To establish the structure of ferric ions in strongly alkaline (pH > 13) environments, aqueous NaOH solutions supersaturated with respect to Fe(III) and the solid ferric-hydroxo complex salts precipitating from them have been characterized with a variety of experimental techniques. From UV measurements, in solutions of pH > 13, only one kind of Fe(III)-hydroxo complex species was found to be present. The micro crystals obtained from such solutions were proven to be a new, so far unidentified solid phase. Mössbauer spectra of the quick-frozen solution and that of the complex salt indicated a highly symmetrical ferric environment in both systems From the EXAFS and XANES spectra, the environment of the ferric ion in these solutions (both native and quick-frozen) and in the complex salt was found to be different. In the complex salt, the bond lengths are consistent with an octahedral coordination around the ferric centres. In solution, the coordination geometry of Fe(III) is most probably tetrahedral. Our results demonstrate that in strongly alkaline aqueous solutions, ferric ions behave very similarly to other structurally related tervalent ions, like Al(III) or Ga(III).

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Section: Introductionmentioning

confidence: 56%

Section: Mössbauer Spectra Of the Solid Ferric-hydroxo Complex Salt A...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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The structure of Fe(iii) ions in strongly alkaline aqueous solutions from EXAFS and Mössbauer spectroscopy

et al. 2008

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“…Hydrogen peroxide is added simultaneously-creating Fenton's reagent. At the cathode, OH -is produced-favouring further the formation of small hydroxides [7]. The heavy metal and arsenic removal mechanisms are several, and these include ion exchange, cementation, specific adsorption and precipitation [3,4,8].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical peroxidation as a tool to remove arsenic and copper from smelter wastewater

et al. 2009

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Electrochemical peroxidation (ECP) is a method that recently has been applied in the treatment of heavy metal polluted wastewater. This method is based on the anodic dissolution of iron to ferrous ions that reacts with H 2 O 2 to produce tiny particles of ferric oxides. These oxides adsorb metals efficiently from aqueous solutions. In the present study, the technique was tested experimentally on copper smelter wastewaters with high concentrations of copper and arsenic. A completely mixed airlift batch reactor was used, and the copper and arsenic removal was measured both for synthetic and real wastewater samples. The concentric iron electrodes acted as ferrous ion source when applying a constant direct current with current reversal every minute and the H 2 O 2 was added dropwise. Initial pH was fixed at 3.5, 5.0 and 6.5, respectively. The best results with the synthetic wastewater showed [99% removal of copper and 80% removal of arsenic (at pH 6.5). When treating the real wastewater samples, both arsenic and copper could be removed more than 99% for all pH levels studied. It can be concluded that presence of other substances in the real wastewater favours the arsenic adsorption and/or precipitation. The copper and arsenic removal velocity was found to be dependent of pH-with the fastest removal at pH 3.5. The ECP could be regarded as a promising remediation method for treating highly contaminated wastewaters since arsenic (from 1000 mg L -1 ) and copper (from 300 mg L -1 ) was removed nearly completely from copper smelter wastewaters.

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⁵⁷Fe Mössbauer Spectroscopy In The Investigation of The Precipitation of Iron Oxides

Musić¹,

Ristić²,

Krehula³

2013

Mössbauer Spectroscopy

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Mössbauer study of ferric hydroxides and hydroxo complexes and their bahaviour in alkaline electrolytes

Cited by 17 publications

References 14 publications

The structure of Fe(iii) ions in strongly alkaline aqueous solutions from EXAFS and Mössbauer spectroscopy

The structure of Fe(iii) ions in strongly alkaline aqueous solutions from EXAFS and Mössbauer spectroscopy

Electrochemical peroxidation as a tool to remove arsenic and copper from smelter wastewater

⁵⁷Fe Mössbauer Spectroscopy In The Investigation of The Precipitation of Iron Oxides

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Mössbauer study of ferric hydroxides and hydroxo complexes and their bahaviour in alkaline electrolytes

Cited by 17 publications

References 14 publications

The structure of Fe(iii) ions in strongly alkaline aqueous solutions from EXAFS and Mössbauer spectroscopy

The structure of Fe(iii) ions in strongly alkaline aqueous solutions from EXAFS and Mössbauer spectroscopy

Electrochemical peroxidation as a tool to remove arsenic and copper from smelter wastewater

57Fe Mössbauer Spectroscopy In The Investigation of The Precipitation of Iron Oxides

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⁵⁷Fe Mössbauer Spectroscopy In The Investigation of The Precipitation of Iron Oxides