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Influence of Silicon and Phosphorus on Structural and Magnetic Properties of Synthetic Goethite and Related Oxides
Electron diffraction Ferrihydrite Goethite Mossbauer spectroscopy Phosphorus Silicon X-ray powder diffraction
2012/1/9
A series of synthetic goethites containing varying amounts of Si and P dopants were characterized by X-ray powder diffraction, electron diffraction, microbeam electron diffraction, and M鰏sbauer spectr...
Cation-Exchange Properties of (Al + Na)-Substituted Synthetic Tobermorites
Cation exchange Cation substitution Cs-exchange Synthesis Tobermorite
2012/1/11
Tobermorite, Ca5Si6O16(OH)2·4H2O, is a hydrous calcium silicate that has a layer-type of structure similar to that of the 2:1 clay minerals. In its natural form, tobermorite exhibits little or no exch...
Preparation and Characterization of Bidimensional Zeolitic Structures Obtained from Synthetic Beidellite and Hydroxy-Aluminum Solutions
Acid sites Beidellite Hydroxy-Al Infrared spectroscopy Nuclear magnetic resonance Pillaring Synthesis
2012/1/11
Beidellite was synthesized hydrothermally from a noncrystalline gel at 320°C and 130 bar pressure. The beidellitic character of the product was verified by infrared spectroscopy on the NH4+-exchanged ...
Relationship among Derivative Spectroscopy, Color, Crystallite Dimensions, and Al Substitution of Synthetic Goethites and Hematites
Aluminum Color Fiber-optic Doppler anemometry Goethite Hematite Visible spectroscopy
2012/1/13
Nine hematites and 22 goethites were synthesized by a variety of methods to obtain monomineralic samples having a range of Al substitutions and particle sizes. The second derivative of absorbance and ...
Effect of Heating on Microcrystalline Synthetic Goethite
Crystallite size Goethite Microstrain Mossbauer spectroscopy Thermal treatment X-ray powder diffraction
2011/11/25
Abstract: The effect of heating synthetic microcrystalline goethite at 60°, 80°, and 105°C was studied by X-ray powder diffraction, electron microscopy, weight-loss measurements, and Mössbauer sp...
Transformation of Synthetic Birnessite to Cryptomelane: An Electron Microscopic Study
Birnessite Cryptomelane Selected area diffraction Structural disorder Synthesis Thermal treatment Transmission electron diffraction
2012/1/12
Na-saturated birnessite was synthesized by oxidizing an alkaline MnCl2 solution with gaseous O2. Transmission electron microscopy (TEM) showed no morphological change upon K-saturation of the birnessi...
Dehydration of Synthetic Hydrated Kaolinites: A Model for the Dehydration of Halloysite(10A)
Dehydration Halloysite Hydrite Kaolinite Water
2012/2/2
Several hydrates can be synthesized from well-crystallized kaolinites; of importance to the present work are a 10-Å hydrate (called the QS-10 hydrate), an 8.6-Å hydrate, and two kinds of p...
Cation and Anion Retention by Natural and Synthetic Allophane and Imogolite
Adsorption Allophane Anion retention Cation retention Imogolite SiO2/Al2O3 ratio Surface charge
2012/2/6
The negative surface charge of synthetic allophanes with a range of Si/Al ratios decreased and positive charge increased with increasing alumina content at a given pH. The phosphate adsorption capacit...
Effect of the Removal of Reactive Surface Material on the Solubility of Synthetic Gibbsites
Acid solubility Gibbsite Scanning electron microscopy Solution Structural defects
2012/2/7
The solubility of four different gibbsite preparations was measured, including two commercial hydrated aluminas produced by Alcoa, a Fisher ACS-grade Al(OH)3, and a laboratory preparation. The Alcoa s...
Interaction of Uranyl Ions with Synthetic Zeolites of Type A and the Formation of Compreignacite-Like and Becquerelite-Like Products
Becquerelite Compreignacite Synthesis Uranium X-ray powder diffraction Zeolite A
2012/2/7
Uranyl acetatye solutions, ranging in concentration from about 100 ppm to 3700 ppm, were re-acted with the Na-, K-, and Ca- forms of zeolite A. The crystalline products from the Na- and K-A zeolites r...
Physico-Chemical Properties of Synthetic Hydrotalcites in Relation to Composition
Crystal strain Hydrotalcite Solid solution Synthesis Thermal stability
2011/11/22
Abstract: Hydrotalcite solid solutions were prepared by coprecipitation followed by hydrothermal treatment between 150° and 250°C. Based on the structural formula [Mg1−xAlx(OH)2]X+[(CO3)x/2ͺ...
The Influence of Aluminum on Iron Oxides. VII. Substitution of Al for Fe in Synthetic Lepidocrocite
Aluminum Goethite Iron Lepidocrocite Substitution Synthesis
2012/2/9
The presence of Al hydroxy species in solution during the synthesis of lepidocrocite had been previously found to influence the reaction towards goethite formation. However, under certain conditions, ...
Cation-Exchange Behavior of Clays and Synthetic Aluminosilica Gels
Amorphous Material Ca/Mg K//NH4 Methylene Blue Montmorillonite Vermiculite
2012/2/9
Cation-exchange capacities determined by methylene blue adsorption (CEC MB) and by the amount of K displaced from a K-saturated clay by NH4 (CEC K//NH4) correlate closely in five soil clays from Penns...
Amorphous and Crystalline Titanium and Iron-Titanium Oxides in Synthetic Preparations, at near Ambient Conditions, and in Soil Clays
Anatase Goethite Hematite Iron Pseudorutile Synthesis Titanium
2012/2/10
A series of mixed iron and titanium oxide coprecipitates ranging in composition between 0 < Ti/Ti + Fe < 1 was synthesized and aged under varying conditions of pH, temperature and time in order to est...
Synthetic Kaolinites Doped with Fe2+ and Fe3+ Ions
Synthetic Kaolinites Fe3+ Ions Electron Spin Resonance
2012/2/13
Previous studies by Electron Spin Resonance (ESR) have established the substitution of Fe3+ and Mg2+ in the kaolinite structure. It is shown that Fe2+ can substitute in kaolinite and stabilize defects...