Search results for "Lepidocrocite"
showing 5 items of 5 documents
Structural characterization of iron oxide/hydroxide nanoparticles in nine different parenteral drugs for the treatment of iron deficiency anaemia by …
2013
Drug products containing iron oxide and hydroxide nanoparticles (INPs) are important for the treatment of iron deficiency anaemia. Pharmaceuticals prepared by the complexation of different kinds of INPs and carbohydrates have different physicochemical and biopharmaceutic characteristics. The increasing number of parenteral non-biological complex drugs (NBCD) containing iron requires physicochemical methods for characterization and enabling of cross comparisons. In this context the structure and the level of crystallinity of the iron phases may be connected to the in vitro and in vivo dissolution rates, which etiologically determine the therapeutic and toxic effects. X-ray powder diffraction…
Transformation of clay-sized minerals in soils exposed to prolonged regular alternation of redox conditions
2016
Abstract The direction of the transformation of Fe-bearing minerals under harshly changing redox conditions is still under debate. Some studies suggest preferential accumulation of weakly crystalline Fe oxides while other studies showed that repeated redox cycles favour the presence of crystalline phases. Since characterized by distinct redox cycles, paddy soils are ideal for studying redox-related transformations of Fe oxides and Fe-bearing clay minerals. We analysed changes in the Fe mineral assemblage upon long-term reduction–oxidation cycles along a chronosequence of 100, 700, and 2000-year-old paddy soils developed on comparable parent material relative to two non-irrigated counterpart…
In-situ transformation of iron-bearing minerals in marshland-derived paddy subsoil
2016
Transformations of Fe-bearing minerals under alternating redox conditions are not fully understood. In-situ approaches under field conditions have rarely been used. We exposed mesh bags containing ferrihydrite, goethite or nontronite to changing redox conditions in subsoil that had been under paddy management for 100, 700 and 2000 years. After 12 months, the minerals were retrieved and analysed for organic carbon and by X-ray diffraction; in addition, nontronite was analysed for cation exchange capacity and by Mossbauer spectroscopy at 278 and 4.2 K. Field exposure of the test minerals was complemented by measurements of soil redox potential and analyses of soil water. Minerals accumulated …
Preparation of magnetic composites of MIL-53(Fe) or MIL-100(Fe) via partial transformation of their framework into γ-Fe2O3
2016
A novel two-step approach is proposed to obtain magnetically active composite materials consisting of MIL-53(Fe) or MIL-100(Fe) and γ-Fe2O3 particles. The first step consists in a partial transformation of the framework into a layer of γ-FeO(OH) (lepidocrocite) covering the MOF particles. We found that such a transformation can be realized under air-free conditions by hydrolysing the MOFs at pH 6.2 in the presence of FeSO4. In the second step the obtained γ-FeO(OH)/MOF composite is heated under an air flow at 250 °C in order to transform γ-FeO(OH) to γ-Fe2O3. The thus prepared composites containing 40 wt% of the magnetic phase were characterized in detail by XRD, HRTEM, FESEM, N2 adsorption…
Electroless synthesis of lepidocrocite (γ-FeOOH) nanotubes in ion track etched polycarbonate templates
2012
In this study, we describe the electroless synthesis of lepidocrocite (γ-FeOOH) nanotubes produced in ion track etched polycarbonate foils. The foils act as templates after they had been irradiated with heavy ions to produce latent tracks that were etched with a desired diameter. Templates are used to fabricate shape formed 1D nanostructures in general. The synthesis of lepidocrocite nanotubes was carried out in a simple two-step method: firstly, particles were formed by precipitation in aqueous solution; secondly, nanotubes were produced by the deposition of the particles inside the nanochannels of the polycarbonate template. Solvent effects were considered to achieve homogeneous growth re…