Search results for "Iron oxide"
showing 10 items of 114 documents
Microanalysis of the surfaces of natural iron-based minerals by means of synchrotron radiation based experimental techniques
2001
We investigated the surfaces of natural iron-based minerals that are magnetite, hematite, goethite, pyrite, pyrrhotite, chalcopyrite, bornite and vivianite, using synchrotron radiation based techniques. Most iron chalkogenides are very suitable for photoemission microscopy studies due to their low resistivity, which prevents from surface charging. The local compositions were studied employing photoemission microscopy in combination with X-ray absorption spectroscopy. Imaging of the sample in the near-edge region of the absorption edges was used to visualise the spatial distributions of the chemical phases on the surface. Distributions of trace elements are imaged with high chemical and late…
Study of the structural phase transformation of iron oxide nanoparticles from an Fe2+ ion source by precipitation under various synthesis parameters …
2015
Abstract Magnetite nanoparticles were precipitated from a pure aqueous ferrous salt solution in an air atmosphere. The influence of the solution molarity, the rate of precipitator agent addition, stirring time and annealing temperature was studied. The morphology, crystalline phase purity and magnetic properties of the obtained powders were studied by X-Ray powder diffraction (XRD), Scanning electron microscopy (SEM), Differential thermal analysis (DTA), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) and Vibrating sample magnetometer (VSM). The synthesis conditions were seen to have an effect on phase composition. It was possible to obtain near stoichiometric Fe…
Development of iron oxide / activated carbon nanoparticle composite for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution
2018
Iron oxide (Fe3O4) and iron oxide/activated carbon (Fe3O4/AC) were fabricated by co-precipitation method for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution in batch mode. These nanoparticles were characterized by BET, FTIR, XRD, SEM/TEM and VSM. The optimum conditions for the removal of ions were pH = 2 for Cr(VI) and 6 for Cu(II) and Cd(II), initial metal ion concentration = 50 mg L−1, nanoparticle dose = 50 mg/10 mL, temperature = 25 ± 1 °C, shaking speed = 180 rpm and contact time = 3 h. The equilibrium data of ions sorption were well described by Langmuir, Freundlich, Redlich-Peterson and Intraparticle Diffusion model. The R2 values obtained by Langmuir model were h…
Use of Super Paramagnetic Iron Oxide Nanoparticles as Drug Carriers in Brain and Ear: State of the Art and Challenges
2021
International audience; Drug delivery and distribution in the central nervous system (CNS) and the inner ear represent a challenge for the medical and scientific world, especially because of the blood–brain and the blood–perilymph barriers. Solutions are being studied to circumvent or to facilitate drug diffusion across these structures. Using superparamagnetic iron oxide nanoparticles (SPIONs), which can be coated to change their properties and ensure biocompatibility, represents a promising tool as a drug carrier. They can act as nanocarriers and can be driven with precision by magnetic forces. The aim of this study was to systematically review the use of SPIONs in the CNS and the inner e…
Conversion of Xylose to Furfural over Lignin-Based Activated Carbon-Supported Iron Catalysts
2020
In this study, conversion of xylose to furfural was studied using lignin-based activated carbon-supported iron catalysts. First, three activated carbon supports were prepared from hydrolysis lignin with different activation methods. The supports were modified with different metal precursors and metal concentrations into five iron catalysts. The prepared catalysts were studied in furfural production from xylose using different reaction temperatures and times. The best results were achieved with a 4 wt% iron-containing catalyst, 5Fe-ACs, which produced a 57% furfural yield, 92% xylose conversion and 65% reaction selectivity at 170 °
Multifunctional polymer-derivatized γ-Fe2O3 nanocrystals as a methodology for the biomagnetic separation of recombinant His-tagged proteins
2008
Abstract Multifunctional polymer-derivatized superparamagnetic iron oxide (γ-Fe2O3) nanoparticles were prepared for biomagnetic separation of histidine-tagged recombinant proteins building up a faster and efficient method for protein separation by making use of their intrinsic magnetic properties. Using polymer bound γ-Fe2O3 nanocrystals, a 6× histidine-tagged recombinant protein (silicatein) with a molecular weight of 24 kDa has been isolated and purified. The supermagnetic iron oxide nanocrystals were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), SQUID and Mossbauer and the polymer functionalization of the γ-Fe2O3 nanocrystals was monitored by UV–vi…
Fast and continuous synthesis of nanostructured iron spinel in supercritical water: influence of cations and citrates
2014
International audience; Spinel iron oxide nanoparticles were obtained under supercritical water conditions in a continuous and fast (less than 10s) way by modifying the initial stoichiometric Fe II /Fe III molar ratio from (1/2) to (3/0), without base solution, and using citrates directly with iron precursors. This result opens the way of an economical and environmentally benign approach to synthesize superparamagnetic iron oxide nanoparticles (SPIONs) in important yields.
Iron and iron-oxide magnetic nanoparticles as signal-amplification elements in electrochemical biosensing
2015
Abstract Growing demands for ultrasensitive biosensing have led to the development of numerous signal-amplification strategies. Based on their unique properties (i.e., electro-conductivity, bio-compatibility and ease of synthesis), various iron magnetic nanoparticles (MNPs) have proved to be an excellent nanomaterial for applications in electrochemical biosensing. This review shows how iron MNPs have made significant contributions in the development of electrochemical nanobiosensors, including immuno-, enzyme, DNA and aptamer types. More importantly, we discuss in detail different aspects of the electrochemical biosensors (e.g., modes of magnetic particles, detection techniques, analytes an…
Magnetic Composite Thin Films of FexOy Nanoparticles and Photocrosslinked Dextran Hydrogels
2012
Abstract Magnetic hydrogel composites are promising candidates for a broad field of applications from medicine to mechanical engineering. Here, surface-attached composite films of magnetic nanoparticles (MNP) and a polymeric hydrogel (HG) were prepared from magnetic iron oxide nanoparticles and a carboxymethylated dextran with photoreactive benzophenone substituents. A blend of the MNP and the dextran polymer was prepared by mixing in solution, and after spin-coating and drying the blend film was converted into a stable MNP–HG composite by photocrosslinking through irradiation with UV light. The bulk composite material shows strong mobility in a magnetic field, imparted by the MNPs. By util…
Iron oxide-based magnetic photocatalysts: Recent developments, challenges, and environmental applications
2021
Abstract Magnetic separation of the solid photocatalyst from the reacting suspension has received great interest in recent research because it offers a suitable way for removing and recycling the heterogeneous photocatalytic material particles preventing the agglomeration and sedimentation during and after their use. The use of iron oxides such as heterogeneous photocatalysts is an appropriate choice to obtain a suitable photocatalyst easily separable from the fluid. This chapter presents a detailed investigation of iron oxide-based magnetic photocatalysts (IOMPs). We will discuss the required conditions for the synthesis of these photocatalysts, followed by their applications for the remov…