Study of the Evolution in the Iron Oxide Synthesis by Hydrothermal Process

Delgado, Eduardo Hurtado; Bohórquez, A.; Alcázar, G. Pérez; Bolaños, Alberto

doi:10.1023/b:hype.0000003773.12577.7f

Cited by 5 publications

(3 citation statements)

References 3 publications

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“…3). The transformation of HFO to c-FeOOH is an uncommon pathway because HFO is unstable to goethite or hematite under aerobic conditions (e.g., Lindsay 1979;Schwertmann and Murad 1983;Delgado et al 2003). If HFO is considered close to Fe(OH) 3 in stoichiometry, the biogenic Fe(II)-catalyzed transformation of HFO to LPD without redox reaction can be roughly expressed in this way:…”

Section: Discussionmentioning

confidence: 99%

Mössbauer hyperfine parameters of iron species in the course of Geobacter-mediated magnetite mineralization

Zhu

Deng

2011

Phys Chem Minerals

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Amorphous ferric iron species (ferrihydrite or akaganeite of \5 nm in size) is the only known solid ferric iron oxide that can be reductively transformed by dissimilatory iron-reducing bacteria to magnetite completely. The lepidocrocite crystallite can be transformed into magnetite in the presence of abiotic Fe(II) at elevated pH or biogenic Fe(II) with particular growth conditions. The reduction of lepidocrocite by dissimilatory iron-reducing bacteria has been widely investigated showing varying results. Vali et al.

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Section: Discussionmentioning

confidence: 99%

Mössbauer hyperfine parameters of iron species in the course of Geobacter-mediated magnetite mineralization

Zhu

Deng

2011

Phys Chem Minerals

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“…In particular, a high temperature hydrothermal process using autoclave often results in a small isomer shift. 40 Also, the electric quadrupolar shift values are found to be 3 ¼ À0.105 $ À0.107 mm s À1 . The magnetic hyperfine fields of the present 40 From these results, we conclude that the samples consist only of the a-Fe 2 O 3 crystalline phase.…”

Section: Resultsmentioning

confidence: 91%

Solvent controlled synthesis of new hematite superstructures with large coercive values

Chaudhari

Kim

et al. 2012

CrystEngComm

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Various morphologies of hematite (a-Fe 2 O 3 ) superstructures such as grape, cube, dumbbell, and microsphere shapes have been reproducibly obtained by a caffeine-assisted environmentally benign one-step hydrothermal synthesis route in the presence of different solvents. The hematite superstructures are formed by self-assembled aggregation of smaller particles of a few nanometres. It is demonstrated that systematic control over the studied experimental conditions (caffeine, solvents, concentration, reaction time, etc.) efficiently alters the structural and magnetic properties of the iron oxide nanostructures. In particular, the solvent plays a key role for overall architecture of the oxide particles under different polar conditions. Magnetic hysteresis measurements reveal that the shape of nanostructures has a remarkable effect on the magnetic properties at room temperature. Interestingly, the coercive values are much higher at room temperature than those at lower temperature for the a-Fe 2 O 3 superstructures prepared in this work.

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“…Los nano óxidos de hierro han sido sintetizados por diferentes de métodos. Así, las partículas pueden ser producidas por métodos químicos húmedos, precipitación a temperatura ambiente (Mandel et al 2011), mediación de surfactante, sol gel (Jitianu et al 2002, Senoy et al 2008, proceso hidrotérmico (Delgado et al 2003), precipitación mediada con tensoactivo, descomposición térmica (Shao et al 2005), emulsiónprecipitación, microemulsión precipitación (Chin & Yaacob 2007), electro-deposición (Masanobu 2010), técnica hidrotérmica asistida por microondas, sonoquímica (Shafi et al 2001, Srivastava et al 2002, pirólisis por pulverización ultrasónica, métodos electroquímicos (Satyawati et al 2006), entre muchos otros (Grabis et al 2008, Teja & Koh 2009, Mohapatra & Anand 2010, Osipov et al 2012.…”

Section: Introductionunclassified

Modificación del proceso de reducción expansiva para la síntesis de nanopartículas de hierro

Rodríguez

Zea²

2014

Univ. Sci.

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The reductive expansion method has been used successfully in the synthesis of metal nanoparticles. However, there are no reports regarding the use of expansion methods to produce oxidized nanoparticles. Here, we propose an adjustment to the current oxidizing atmosphere application during reductive expansion. Mixtures of different weight ratios of iron nitrogen salts and urea (blowing agent) were subjected to thermal shock in an oven; the sudden sublimation of the urea and nitrogen salts originated a fine dispersion of material that came into contact with reducing gases. During this sublimation, metallic iron nanoparticles were produced and subsequently oxidized by the prevailing oxidizing atmosphere. Through characterization using X-ray diffraction, we determined that the crystalline phase of the formed nanoparticles depends on the composition of the reactants. In contrast, particle size distribution, surface area and oil absorption are not strongly influenced by this composition.

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Study of the Evolution in the Iron Oxide Synthesis by Hydrothermal Process

Cited by 5 publications

References 3 publications

Mössbauer hyperfine parameters of iron species in the course of Geobacter-mediated magnetite mineralization

Mössbauer hyperfine parameters of iron species in the course of Geobacter-mediated magnetite mineralization

Solvent controlled synthesis of new hematite superstructures with large coercive values

Modificación del proceso de reducción expansiva para la síntesis de nanopartículas de hierro

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