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Abstract: High-resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), annular dark-field scanning transmission electron microscope (STEM) images, and electron ...
Abstract: The distribution and chemical state of Si in a synthetic 2-line ferrihydrite with a Si/(Si + Fe) molar ratio of 0.11 was studied. Heat treatment under oxidizing conditions shows that Si-rich...
Abstract: Iron oxides in surface environments generally form at temperatures of 25 ?10癈, but synthesis experiments are usually done at higher temperatures to increase the rate of crystallization. To m...
Abstract: The effects of neodymium (Nd) on the transformation of ferrihydrite to iron oxides was studied. The possible isomorphous substitution of Nd3+ for Fe3+ in iron oxides was examined also. Nd wa...
Abstract: We investigated the crystallization of ferrihydrite prepared by hydrolysis of Fe(NO3)3 solutions containing phosphate. Crystallization was studied at different pH (3–9), temperatures (298, 3...
Abstract: Minerals in surface environments form in both turbulent and non-turbulent systems. This study compares the properties of Al goethite formed from ferrihydrite at 60 °C in 0.3 M KOH with and w...
Abstract: A structural model for the geometry of Fe(III) octahedra near the surface of finely divided ferrihydrite was elaborated based on the bond梫alence theory and by considering the interaction of ...
X-ray absorption fine structure (XAFS) spectra were collected on a series of ferrihydrite samples prepared over a range of precipitation and drying conditions. Analysis of the XAFS pre-edge structures...
Abstract: Two-line ferrihydrite is an important adsorbent of many toxics in natural and anthropogenic systems; however, the specific structural sites responsible for the high adsorption capacity are n...
X-ray diffraction of four natural samples of ferrihydrite indicates the presence of crystalline domains within the primary particles. The average diameter of the primary particles (determined from low...
Color variations from brown to yellow of synthesized goethite have been studied colorimetrically and spectroscopically. Goethite with various colors was synthesized at pH 13 and 40°C by varying the in...
57Fe M鰏sbauer spectra of two synthetic samples of ferrihydrite, recorded at 4.2 K in applied fields of up to 9 T, have been analysed by a mean-field model. The samples exhibit two and six X-ray diffra...
Ferrihydrite samples having Si/Fe molar ratios ranging from 0 to 1 were synthesized by the reaction of Fe2(SO4)3 and Na2SiO3 with NaOH to an equilibrium pH of 8.2. Hematite formed by incubating the fe...
Abstract: At pH 12 Co-ferrihydrite transformed to either Co-goethite or Co-magnetite, the latter compound appearing at Co additions of > 18 mole %. Although Co was readily taken up by the magnetite st...
The transformation of ferrihydrite to goethite and/or hematite, as influenced by the presence of co-precipitated Si, was investigated by infrared spectroscopy (IR), X-ray powder diffraction (XRD), and...

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