Charge properties of red Argentine soils as an indicator of iron oxide/clay associations

Soil Research ◽  
2001 ◽  
Vol 39 (2) ◽  
pp. 423 ◽  
Author(s):  
R. M. Torres Sánchez ◽  
M. Okumura ◽  
R. C. Mercader
Keyword(s):  
Iron Oxide ◽  
Iron Oxides ◽  
Photoelectron Spectroscopy ◽  
Electron Probe ◽  
Surface Coverage ◽  
Oxide Coating ◽  
Point Of Zero Charge ◽  
X Ray Diffraction ◽  
X Ray ◽  
North Eastern

The order of the relative degree of iron oxide coating of 4 samples of red soils from north-eastern Argentina was established using the point of zero charge (PZC), yielded by potentiometric titration, and the isoelectric point (IEP), obtained from the diffusion potential. When PZC is different from IEP, the relative fraction of apparent surface coverage could be assessed from the IEP. The results obtained by the application of X-ray diffraction, scanning electron microscopy, electron probe microanalysis, X-ray photoelectron spectroscopy, Mössbauer spectroscopy, and specif ic surface area, although essential to characterise the samples, did not allow us to determine the degree of iron oxide coating. Our findings show that the order of this degree is opposite to the order of the ratio of the amount of free iron oxides to that of clay in iron oxides/clay mixtures.

scholarly journals Discovery of Fe7O9: a new iron oxide with a complex monoclinic structure

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ryosuke Sinmyo ◽  
Elena Bykova ◽  
Sergey V. Ovsyannikov ◽  
Catherine McCammon ◽  
Ilya Kupenko ◽  
...  
Keyword(s):  
Applied Sciences ◽  
Crystal Structure ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Industrial Applications ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Insight Into

Abstract Iron oxides are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary iron oxide with the hitherto unknown stoichiometry of Fe7O9. This new oxide was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary iron oxides known to date. The synthesis of Fe7O9 opens a new portal to exotic iron-rich (M,Fe)7O9 oxides with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new iron oxide groups may provide new insight into the cycling of volatiles in the Earth’s interior.

Limitations to the use of Sb as a Surfactant During SiGe MBE

1998 ◽  
Vol 533 ◽  
Author(s):  
Glenn G. Jernigan ◽  
Conrad L. Silvestre ◽  
Mohammad Fatemi ◽  
Mark E. Twigg ◽  
Phillip E. Thompson
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Quantum Well ◽  
Photoelectron Spectroscopy ◽  
Surface Coverage ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Alloy Concentration

AbstractThe use of Sb as a surfactant in suppressing Ge segregation during SiGe alloy growth was investigated as a function of Sb surface coverage, Ge alloy concentration, and alloy thickness using xray photoelectron spectroscopy, x-ray diffraction, and transmission electron microscopy. Unlike previous studies where Sb was found to completely quench Ge segregation into a Si capping layer, we find that Sb can not completely prevent Ge segregation while Si and Ge are being co-deposited. This results in the production of a non-square quantum well with missing Ge at the beginning and extra Ge at the end of the alloy. We also found that Sb does not relieve strain in thin films but does result in compositional or strain variations within thick alloy layers.

Al Si Oxide Coating as Ttritium Penetration Barrier on 316L Stainless Steel Prepared by a Combined Process

2008 ◽  
Vol 59 ◽  
pp. 76-81
Author(s):  
Hong Bing Liu ◽  
Jie Tao ◽  
Jiang Xu ◽  
Zhao Feng Chen ◽  
Xian Jun Sun
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrogen Permeability ◽  
Oxide Coating ◽  
Favorable Effect ◽  
X Ray Diffraction ◽  
Combined Process ◽  
X Ray ◽  
Transmission Electron ◽  
Outermost Surface ◽  
Glow Plasma

Based on the favorable effect of the elements Al and Si on the improvement in reducing hydrogen permeability, a new combined process of simultaneous aluminizing and siliconizing, followed by oxidizing treatments using double glow plasma technology on 316L substrate was developed in this work. Microstructure and phase structure of as- prepared coating was examined by scanning electronic microscopy (SEM), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), respectively. The results showed that the simultaneous aluminizing and siliconizing coating consisted of an outer aluminide layer (dissolved Si) and a diffusion zone. After a combined process, a continuous and compact Al2O3-rich coating was formed at the outermost surface. SiO2 was also detectable in the oxide coating.

scholarly journals The Influence of Synthesis Parameters on Structural and Magnetic Properties of Iron Oxide Nanomaterials

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 85 ◽  
Author(s):  
Laura Madalina Cursaru ◽  
Roxana Mioara Piticescu ◽  
Dumitru Valentin Dragut ◽  
Ioan Albert Tudor ◽  
Victor Kuncser ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Crystalline Phase ◽  
Annealing Treatment ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Order Of Magnitude

Magnetic iron oxides have been used in biomedical applications, such as contrast agents for magnetic resonance imaging, carriers for controlled drug delivery and immunoassays, or magnetic hyperthermia for the past 40 years. Our aim is to investigate the effect of pressure and temperature on the structural, thermal, and magnetic properties of iron oxides prepared by hydrothermal synthesis at temperatures of 100–200 °C and pressures of 20–1000 bar. It has been found that pressure influences the type of iron oxide crystalline phase. Thus, the results obtained by Mössbauer characterization are in excellent agreement with X-ray diffraction and optical microscopy characterization, showing that, for lower pressure values (<100 bar), hematite is formed, while, at pressures >100 bar, the major crystalline phase is goethite. In addition, thermal analysis results are consistent with particle size analysis by X-ray diffraction, confirming the crystallization of the synthesized iron oxides. One order of magnitude higher magnetization has been obtained for sample synthesized at 1000 bar. The same sample provides after annealing treatment, the highest amount of good quality magnetite leading to a magnetization at saturation of 30 emu/g and a coercive field of 1000 Oe at 10 K and 450 Oe at 300 K, convenient for various applications.

Formation of maghemite nanoparticles in bismuth telluride materials containing iron

2010 ◽  
Vol 25 (10) ◽  
pp. 2042-2046
Author(s):  
R.M. Catchings ◽  
A.N. Thorpe ◽  
J.R. Grant ◽  
R. Douglas ◽  
C. Viragh ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Bismuth Telluride ◽  
Photoelectron Spectroscopy ◽  
Chemical Method ◽  
Oxide Nanoparticles ◽  
Maghemite Nanoparticles ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Wet Chemical

Bismuth telluride (Bi2Te3) systems containing 2%, 4%, and 8% of iron were prepared using a low temperature wet chemical method. Iron oxide nanoparticles were formed when the samples were heated in hydrogen at 250 °C for at least six hours. The samples were characterized by x-ray diffraction, magnetization, magnetic susceptibility, x-ray photoelectron spectroscopy, Mössbauer spectroscopy, and wet chemical analysis measurements. The nanoparticles of iron oxide were identified as γ-Fe2O3 with a particle size of ˜5 nm.

scholarly journals Phosphate adsorption onto bagasse iron oxide biochar: Parameter optimization, kinetic analysis, and study of mechanism

BioResources ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1335-1357
Author(s):  
Qing Zhang ◽  
Yan-mei Ding ◽  
Lin Lu ◽  
Jing-xi Li ◽  
Mei-na Liang ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Photoelectron Spectroscopy ◽  
Phosphate Adsorption ◽  
Phosphorus Concentration ◽  
X Ray Diffraction ◽  
Phosphorus Adsorption ◽  
X Ray ◽  
Bet Specific Surface Area ◽  
Ph Range

This study combined chemical ultrasonic modifications and microwave oven heating to prepare a novel adsorbent, bagasse iron oxide biochar, (BIBC) to remove phosphate from aqueous solutions. The characterization of BIBC was made by energy dispersive spectrometry (EDS), Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses, and the mechanism of phosphorus adsorption on BIBC was researched by adsorption batch experiments with emphasis on pH, dosages of BIBC, initial phosphorus concentration, and adsorption time. The BIBC’s BET specific surface area and pore volumes were 81.94 m2 g−1 and 26.74 cm3 g−1, respectively. The pH for the optimal phosphorus adsorption by BIBC ranged from 5.0 to 7.0. The maximum adsorption capacities of phosphorus (according to the Langmuir model) were 3.62, 4.06, and 4.32 mg g-1 at temperatures of 25, 35, and 45 °C, respectively. Electrostatic interaction, surface adsorption of phosphorus on BIBC, and ion exchange were the main mechanisms of phosphorus adsorption. According to XPS results, Fe2p was involved in the adsorption reaction. The adsorption of phosphorus by BIBC is considered to be mainly chemical adsorption. The BIBC was stable under a pH range from 4.0 to 10.0 and secondary pollution did not result.

scholarly journals Synthesis of an Anticorrosive Pigment by Thermal Treatment of Iron Oxides from Steel Industry Wastes

2019 ◽  
Vol 28 (52) ◽  
pp. 43-58
Author(s):  
María Angélica Colpas-Ruiz ◽  
Camilo Gnecco-Molina ◽  
Gabriel Antonio Jiménez-Rodríguez ◽  
José Andrés Pérez-Mendoza ◽  
Óscar Fabián Higuera-Cobos
Keyword(s):  
Iron Oxide ◽  
Thermal Treatment ◽  
Iron Oxides ◽  
Steel Industry ◽  
Powder Steel ◽  
Total Iron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Industry Waste ◽  
Different Temperatures

This work reports the obtaining of an anticorrosive pigment composed mainly of hematite (ɑ-Fe2O3) from a powder steel industry waste from rust scale of rebar steel. This residue is mainly composed of Fe2O3 (87.97 %), SiO2 (6.13 %), CaO (1.88 %), Al2O3 (1.30%) and MnO (0.77 %). The total iron oxide of the residue is constituted by the following crystalline phases: magnetite, maghemita, lepidocrocita, wüstite, goethite and hematite. The production of a pigment with a high content of hematite was possible thanks to the high content of precursor iron oxides, which were calcined at different temperatures (750-850 °C) and holding times (0.5-1.50 h). For characterizing the iron content chemically and to identify their iron oxides phases, it was used X-ray fluorescence (XRF) and X-ray diffraction (XRD). The results showed that the pigment with the highest amount of hematite (ɑ-Fe2O3) was obtained at a calcination temperature of 850 °C and a holding time of 1.00 h.

Lead Corrosion and Formation of Lead Oxides from a Lead-air Cell in Methanesulfonic Acid

2017 ◽  
Vol 19 (4) ◽  
pp. 217-222
Author(s):  
Wan Jeffrey Basirun ◽  
Idris Mohamed Saeed ◽  
Hanieh Ghadimi ◽  
Magaji Ladan ◽  
Mohammad Reza Mahmoudian ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Coverage ◽  
Methanesulfonic Acid ◽  
X Ray Diffraction ◽  
Air Cathode ◽  
X Ray ◽  
Lead Corrosion ◽  
Microscopy Image ◽  
Lead Oxides ◽  
Discharge Field

The corrosion of lead in methanesulfonic acid solution in the presence of a MnO2 air cathode in a primary lead-air cell is in-vestigated. The highest power density of the lead-air cell is 2.8 mW cm-2. X-ray photoelectron spectroscopy and powder X-ray diffraction results demonstrate the formation of lead (II) oxide and lead (IV) dioxide on the air cathode after continuous discharge. Field emission scanning electron microscopy image shows that the surface coverage of lead (II) oxide and lead (IV) dioxide on the air cathode is only partial and will allow oxygen reduction.

The Preparation of Nanosized Iron Oxide Using Hydrolysis Enhanced by CuO and their Characterization

2013 ◽  
Vol 320 ◽  
pp. 275-280 ◽  
Author(s):  
Li Hua Lin ◽  
Jian Li ◽  
Long Long Chen
Keyword(s):  
Iron Oxide ◽  
Photoelectron Spectroscopy ◽  
Experimental Results ◽  
Precipitation Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Weakly Magnetic ◽  
Nanosized Oxide ◽  
Nanosized Iron

By adding CuO into heated Fe (NO3)3 aqueous solution, a precipitation reaction takes place to form nanosized iron oxide. The product obtained were characterized by transmission electron microscopy (TEM), vibrating sample magnetized (VSM), X-ray diffraction (XRD), energy disperse X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The experimental results showed that the product is weakly magnetic nanoclusters based on smaller ferrihydrite Fe5O7(OH)·4H2O nanocrystallites. The nanoclusters are of about 40 nm size and absorbed by Fe (NO3)3. The experimental results are attributed to the Fe (NO3)3 hydrolysis reaction being enhanced by CuO as hydrolyte. A new route is proposed for the preparation of nanosized oxide using hydrolysis enhanced.

Radioisotopic study of 11C-labelling methanol decomposition on iron oxide modified mesoporous MCM-41 silica

2009 ◽  
Vol 87 (3) ◽  
pp. 478-485 ◽  
Author(s):  
Eva Sarkadi-Pribóczki ◽  
Tanya Tsoncheva ◽  
Ljubomira Ivanova
Keyword(s):  
Iron Oxide ◽  
Surface Coverage ◽  
Methanol Conversion ◽  
Methanol Decomposition ◽  
Reaction Pathways ◽  
X Ray Diffraction ◽  
Iron Species ◽  
X Ray ◽  
Temperature Programmed ◽  
Mcm 41

Novel 11C-radiolabelling method was applied for the investigation of methanol conversion on iron oxide modified mesoporous MCM-41. Changes in the selectivity were observed varying the state of the loaded iron species or the degree of the surface coverage with 11C-radiolabelling methanol. Combining the Moessbauer spectroscopy, X-ray diffraction (XRD), N2-physisorption, and temperature-programmed reduction- thermogravimetric (TPR-TG) techniques with the high sensitive 11C-radioisotopic catalytic analysis, the contribution of the different reaction pathways of methanol conversion was discussed.

Sign in / Sign up

Export Citation Format

Share Document