Characterization of Oxidation of Green Rust (Cl&lt;SUP&gt;&amp;minus;&lt;/SUP&gt;) Containing Copper in Aqueous Solution

Nagata, Futoshi; Inoue, Kazuhide; Shinoda, Kōzō; Bergmann, Ingo; Šepelák, V.; Suzuki, Shigeru

doi:10.2320/matertrans.m2009279

Cited by 7 publications

(5 citation statements)

References 19 publications

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“…These behaviors of ORP and pH of the as-synthesized GR(Cl -) suspension are similar to those of previous studies. 23) Before the injection of oxygen gas, the pretreated GR(Cl -) suspension exhibits lower ORP and higher pH in comparison with the as-synthesized GR(Cl -) suspension. These tendencies are maintained during oxidation.…”

Section: Change In Oxidation Process Of Gr(cl -) Suspension By Contromentioning

confidence: 98%

“…[23][24][25][26][27] It has been reported that a small quantity of Fe3O4 particles is nucleated in the GR(Cl -) suspension by the addition of Cu ions. 23) When oxygen gas was injected in such suspension, the formation of Fe3O4 particles was enhanced. It has also been reported that Fe3O4 particles are formed in a GR(Cl -) suspension when the liquid phase of the suspension is replaced by deaerated water before the injection of oxygen gas.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Magnetite Particles by Oxidation of Hydroxyl-chloride Green Rust Suspension under Controlled Conditions

Yoshino¹,

Fujieda²,

Shinoda³

et al. 2013

ISIJ Int.

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Magnetite (Fe3O4) particles were synthesized by oxidation of a hydroxyl chloride green rust (GR(Cl -)) suspension at room temperature. The formation process of Fe3O4 particles was characterized by X-ray diffraction, magnetization and electrochemical measurements. The results showed that a small amount of fine Fe3O4 particles were nucleated when the supernatant solution of the as-synthesized GR(Cl -) suspension was replaced by deaerated water. By controlling the injection of oxygen gas at room temperature, Fe3O4 particles of about 70 nm in diameter formed from such GR(Cl -) suspension, while goethite (α-FeOOH) particles were mainly obtained from the as-synthesized GR(Cl -) suspension under the same oxidation conditions. Hence, the saturation magnetization of final oxidation products obtained from the GR(Cl -) suspension in which the supernatant solution was replaced was about 60 emu/g, which was six times larger than that obtained from the as-synthesized GR(Cl -) suspension. In the early stage of the oxidation process, the oxidation-reduction potential (ORP) in the GR(Cl -) suspension in which supernatant solution was replaced was lower than that in the as-synthesized GR(Cl -) suspension. In addition, the value of pH of the former suspension was higher than that of the latter suspension. It is concluded that the formation of Fe3O4 particles is enhanced in solution with relatively low ORP and high pH.

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Section: Change In Oxidation Process Of Gr(cl -) Suspension By Contromentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Synthesis of Magnetite Particles by Oxidation of Hydroxyl-chloride Green Rust Suspension under Controlled Conditions

Yoshino¹,

Fujieda²,

Shinoda³

et al. 2013

ISIJ Int.

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“…[13][14][15] In this study, we focused on chloride-containing green rust (GR(Cl -)) with the chemical formula Fe(II) 3 Fe(III)(OH) 8 Cl· 2H 2 O, 16) because the corrosion of metallic Fe and steel due to chloride ions is common in various environments. In previous laboratory experiments on the oxidation of GR(Cl -) suspension, 12,[17][18][19][20][21][22] the in situ measurements of electrochemical properties such as pH, dissolved oxygen (DO), and oxidation-reduction potential (ORP) have been performed for the suspension during oxidation. 17) The correlation between the species of the oxidation products and the solution conditions in the suspension during oxidation has been compared with the electrochemical potential (E)-pH equilibrium diagram, including GR(Cl -).…”

Section: Introductionmentioning

confidence: 99%

“…[17][18][19][20][21][22] To investigate the transformation of GR(Cl -) during oxidation, X-ray diffraction pattern of solid particles extracted from the suspension at different oxidation times was also measured. [17][18][19][20][21][22] However, the oxidation process of GR(Cl -) suspension has not been fully understood. For example, the relative amounts of GR(Cl -) and oxidation products in the suspension during oxidation have not been determined, because it is difficult to estimate the fractions of reaction products from X-ray diffraction data.…”

Section: Introductionmentioning

confidence: 99%

In situ Measurements of X-ray Absorption Spectra during Transformation of Green Rust to Ferric Oxyhydroxide Via Aqueous Solution

et al. 2014

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In situ measurements of X-ray absorption spectra at an Fe K absorption edge were carried out during the transformation of chloride-containing green rust (GR(Cl -)) to oxyhydroxide (that is, lepidocrocite (γ -FeOOH)), by oxidation via aqueous solution. Results showed that the Fe K absorption edge in X-ray absorption near-edge structure (XANES) spectrum shifted toward the higher energy side with increasing oxidation time. The factor analysis of the XANES spectra, using reference data, implied that dissolution of GR(Cl -) and precipitation of γ -FeOOH occur simultaneously. The fraction of γ -FeOOH in the suspension increased continuously with increasing oxidation time, in response to the continuous decrease of the fraction of GR(Cl -). The results lead us to conclude that GR(Cl -) transforms to γ -FeOOH during oxidation under the present experimental conditions.

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“…Metallic iron can be easily oxidized in an aqueous solution containing chloride ions; GR(Cl − ), which comprises Fe(II) and Fe(III) ions, is an important precursor and can be easily oxidized to different iron oxides in aqueous solution. The synthesis method of GR(Cl − ) is well established, and the transformation of GR(Cl − ) to iron oxides in aqueous solutions has been studied 20, 21. The results showed that the transformation of GR(Cl − ) to iron oxides has been found to be sensitive to oxidation conditions such as temperature and oxidation rate.…”

Section: Introductionmentioning

confidence: 99%

Transformation of green rust (Cl⁻) into different oxyhydroxides in aqueous solution containing molybdenum ions

Nagata

Inoue

Fujieda

et al. 2011

Materials & Corrosion

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To investigate the influence of the addition of molybdenum ions on the transformation of green rust GR(Cl À ) comprising Fe(II) and Fe(III) into different oxyhydroxides, suspensions of GR(Cl À ) containing molybdenum ions were oxidized by passing nitrogen gas containing oxygen through the suspensions. X-ray diffraction (XRD) was used for identifying the solid particles formed by oxidation. The results showed that in the presence of molybdenum ions, the formation of b-FeOOH and a-FeOOH was enhanced as compared to that of g-FeOOH in the GR(Cl À ) suspensions. This implied that the molybdenum ions interacted with the chloride ions obtained from GR(Cl À ) and induced the formation of b-FeOOH that contained chloride ions. Transmission electron micrographs of the solid particles showed that the particle size of the resulting oxyhydroxides was considerably reduced because of the addition of the molybdenum ions. The pH and oxidation-reduction potential (ORP) of the aqueous solution were also measured during the oxidation. The addition of molybdenum ions was found to cause characteristic changes in the pH and ORP in the initial stage of the oxidation.

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Characterization of Oxidation of Green Rust (Cl<SUP>−</SUP>) Containing Copper in Aqueous Solution

Cited by 7 publications

References 19 publications

Synthesis of Magnetite Particles by Oxidation of Hydroxyl-chloride Green Rust Suspension under Controlled Conditions

Synthesis of Magnetite Particles by Oxidation of Hydroxyl-chloride Green Rust Suspension under Controlled Conditions

In situ Measurements of X-ray Absorption Spectra during Transformation of Green Rust to Ferric Oxyhydroxide Via Aqueous Solution

Transformation of green rust (Cl⁻) into different oxyhydroxides in aqueous solution containing molybdenum ions

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Characterization of Oxidation of Green Rust (Cl<SUP>&minus;</SUP>) Containing Copper in Aqueous Solution

Cited by 7 publications

References 19 publications

Synthesis of Magnetite Particles by Oxidation of Hydroxyl-chloride Green Rust Suspension under Controlled Conditions

Synthesis of Magnetite Particles by Oxidation of Hydroxyl-chloride Green Rust Suspension under Controlled Conditions

In situ Measurements of X-ray Absorption Spectra during Transformation of Green Rust to Ferric Oxyhydroxide Via Aqueous Solution

Transformation of green rust (Cl−) into different oxyhydroxides in aqueous solution containing molybdenum ions

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Product

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Characterization of Oxidation of Green Rust (Cl<SUP>−</SUP>) Containing Copper in Aqueous Solution

Transformation of green rust (Cl⁻) into different oxyhydroxides in aqueous solution containing molybdenum ions