Preparation Of Iron Oxide Research Articles

Preparation and Characterization of Iron Oxides – Polymer Composite Membranes

Composite membranes of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) or ethyl cellulose filled with magnetic nanoparticles, that is, ferroferric oxides (Fe3O4) were prepared. These membranes were examined for nitrogen and oxygen permeability. In the case of ethylcellulose membranes the gas flow was too high, since the macropore were formed. In further permeation measurements PPO membranes with 1 to 10 w/w% magnetic particles content were investigated. For the higher concentration of magnetite (more than 20%) in PPO polymer solution sedimentation phenomenon was observed. Mass transport coefficients (permeation and selectivity) were evaluated. Selectivity of the investigated membranes changed with the weight fraction of magnetic particles from oxygen (plain) towards nitrogen (2 and more w/w%).

Synthesis and characterization of superparamagnetic core–shell micrometre-sized particles of narrow size distribution by a swelling process

In previous publications we described several methods to prepare iron oxide and Fe magnetic nanoparticles entrapped within poly(divinyl benzene) or carbon composite microspheres for various biomedical applications. However, these methods involved relatively complex synthetic processes, the size of the entrapped nanoparticles could hardly be manipulated and the obtained particles were mostly ferromagnetic. The present work describes a new simple approach to overcome these obstacles. For this purpose, core–shell polystyrene/(poly(divinyl benzene)/ferrocene) and polystyrene/(poly(divinyl benzene–styrene)/ferrocene) micrometre-sized particles of narrow size distribution were prepared by a room temperature swelling of uniform polystyrene template microspheres dispersed in an aqueous continuous phase with emulsion droplets of a swelling solvent, such as toluene containing the monomers styrene and/or divinyl benzene, and the initiators azoisobutyronitrile and ferrocene. The monomer(s) within the swollen uniform polystyrene template microspheres were then polymerized at elevated temperature. Superparamagnetic and ferromagnetic poly(divinyl benzene)–Fe3O4 and poly(styrene–divinyl benzene)–Fe3O4 composite microspheres of narrow size distribution were then formed by annealing the previous micrometre-sized composite particles containing ferrocene at 330 °C for 2 h under ambient atmosphere in a sealed cell, followed by the dissolution of the polystyrene template part. This study shows that the size of the Fe3O4 nanoparticles entrapped within the poly(divinyl benzene) and poly(divinyl benzene–styrene) matrices can be controlled by adjusting the [divinyl benzene]/[styrene] volume ratio. Superparamagnetic C–Fe micrometre-sized particles of narrow size distribution were formed by annealing the PDVB–Fe3O4 particles at 450 °C under hydrogen atmosphere for 2 h.

Synthesis, characterization and biocompatibility evaluation of iron oxide incorporated magnetic mesoporous silica

On the basis of a thermal process, a facile, low cost, one-step approach for preparing iron oxide (Fe(2)O(3)) incorporated ordered magnetic mesoporous silica nanocomposites by a co-operative self-assembly approach is presented. Various mesostructured silica materials incorporated with different amounts of iron oxide (nSi/nFe = 1/1, 1/0.5, 1/0.25 and 1/0.123) at various pH (<1, 3, 5 and 7) were synthesized and characterized by electron microscopy and X-ray diffractometry. Further, the surface area and magnetic properties were evaluated using N(2)-sorption analyses, and a superconducting quantum interference device interfaced with a vibrating sample magnetometer (SQUID-VSM) respectively. The transmission electron micrographs and nitrogen sorption analysis indicated that most of the Fe(2)O(3) domains of several nanometers were embedded in the silica walls, rather than dispersed in the mesopores. The incorporation of iron oxide into the mesopores without compromising the structural and textural properties was achieved at pH < 1. These structures have great potential in diagnostics and therapeutics. However, the acceptance of this material by the biological host is a critical issue for such biomedical applications. In this study, we have also evaluated the in vivo biocompatibility of these magnetic mesoporous materials in a rat model. The histopathological results show that this magnetic material can be classified as a level 2 biomaterial that can be safely used for short term applications such as MRI imaging, hyperthermia, targeted drug delivery, etc.

Labeling of mesenchymal stromal cells with iron oxide–poly(l-lactide) nanoparticles for magnetic resonance imaging: uptake, persistence, effects on cellular function and magnetic resonance imaging properties

Background aims. Mesenchymal stromal cells (MSC) are the focus of research in regenerative medicine aiming at the regulatory approval of these cells for specific indications. To cope with the regulatory requirements for somatic cell therapy, novel approaches that do not interfere with the natural behavior of the cells are necessary. In this context in vivo magnetic resonance imaging (MRI) of labeled MSC could be an appropriate tool. Cell labeling for MRI with a variety of different iron oxide preparations is frequently published. However, most publications lack a comprehensive assessment of the noninterference of the contrast agent with the functionality of the labeled MSC, which is a prerequisite for the validity of cell-tracking via MRI. Methods.We studied the effects of iron oxide-poly(L-lactide) nanoparticles in MSC with flow cytom-etry, transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), Prussian blue staining, CyQuant® proliferation testing, colony-forming unit-fibroblast (CFU-F) assays, flow chamber adhesion testing, immuno-logic tests and differentiation tests. Furthermore iron-labeled MSC were studied by MRI in agarose phantoms and Wistar rats. Results. It could be demonstrated that MSC show rapid uptake of nanoparticles and long-lasting intracellular persistence in the endosomal compartment. Labeling of the MSC with these particles has no influence on viability, differentiation, clonogenicity, proliferation, adhesion, phenotype and immunosuppressive properties. They show excellent MRI properties in agarose phantoms and after subcutaneous implantation in rats over several weeks. Conclusions. These particles qualify for studying MSC homing and trafficking via MRI.

Flower-like porous hematite nanoarchitectures achieved by complexation–mediated oxidation–hydrolysis reaction

Flower-like porous hematite (α-Fe 2O 3) nanoarchitectures composed of ultra-thin nanoflakes were prepared by annealing the iron oxide precursor formed via the oxidation-hydrolysis reaction between Fe(II) ions and Tris(hydroxymethyl)aminomethane (abbreviated as Tris). The microstructure of the prepared FeOOH and hematite samples were fully characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, Fourier-transforming infrared spectra, thermogravimetric analysis, and nitrogen adsorption–desorption isotherm. Based on the influences of reactant concentrations, reaction time and reaction temperature on the morphologies of the resultant samples, a formation mechanism of etching was proposed, Fe(II)–Tris complexes were self-assembled via hydrogen bonds into brick-like building blocks, which then aggregated into rudimentary nanoparticles, and the synergistic effect between the crystallization of FeOOH and dissociation of Fe(II)–Tris complexes make the rudimentary nanoparticles evolve into the flower-like products. The as-prepared flower-like α-Fe 2O 3 nanostructures possessed a Brunauer–Emmett–Teller specific surface area of 191.63 m 2 g −1, hierarchical pore distribution ranging from micropores to macropores, and good crystallinity, and excellent visible photocatalysis in terms of removing chemical oxygen demand of dimethyl sulfoxide industrial wastewater. The current work provides a reliable approach for building functional hierarchical nanoarchitectures and the prepared iron oxide nanomaterials demonstrate an excellent ability to remove toxic pollutants in industrial wastewater.

Synthesis of iron oxide nanoparticles via sonochemical method and their characterization

Preparation of iron oxide (α-Fe 2O 3) nanoparticles was carried out via a sonochemical process. The process parameters such as temperature, sonication time and power of ultrasonication play important roles in the size and morphology of the final products. The iron oxide nanoparticles were characterized by transmission electron microscopy, X-ray powder diffraction, and thermogravimetric and differential thermal analyses. From transmission electron microscopy observations, the size of the iron oxide nanoparticles is estimated to be significantly smaller than 19 nm. X-ray diffraction data of the powder after annealing provide direct evidence that the iron oxide was formed during the sonochemical process.

Preparation, characterization and application of superparamagnetic iron oxide encapsulated with N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride

Superparamagnetic iron oxide nanocrystals (SPION) and their colloidal solutions of magnetic nanoparticles (ferrofluid) appear to contribute to the magnetite imaging applications. Here we present an aqueous ferrofluid in physiological pH and its cell tracking potential. In situ coating method was adapted to synthesize N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC)-coated SPION. Characterization results reveal their features as follows: (1) z-average diameter of 274.1 ± 1.934 nm; (2) polydispersity index (PDI) of 0.135 ± 0.029; (3) zeta potential of 11.4 ± 0.410 mV; (4) iron concentration of 5.4 mg Fe/ml; (5) stable in both water and normal saline; (6) uptake by a variety of cell lines and (7) little cytotoxicity. Finally, islet grafting experiments demonstrated the potential usefulness of this product as a MRI contrast agent for cell tracking.

Preparation and Characterization of Iron Oxide–Silica Composite Particles Using Mesoporous SBA-15 Silica as Template and Their Internalization Into Mesenchymal Stem Cell and Human Bone Cell Lines

A new procedure for preparing iron oxide-silica nanocomposite particles using SBA-15 mesoporous silica as a template is described. These composite materials retained the 2-D hexagonal structure of the SBA-15 template. Transmission electron micrograms of the particles depicted the formation of iron oxide nanocrystals inside the mesochannels of SBA-15 silica framework. Powder x-ray diffraction showed that the iron oxide core of the composite particles consists of a mixture of maghemite (gamma-Fe(2)O(3)) and heamatite (alpha-Fe(2)O(3)), which is the predominant component. Superconducting quantum interference device (SQUID) magnetometry studies showed that these iron oxide-silica composite materials exhibit superparamagnetic properties. On increasing the iron oxide content, the composite particles exhibited a stronger response to magnetic fields but a less homogeneous core, with some large iron oxide particles which were thought to be formed outside the mesochannels of the SBA-15 template. Internalization of these particles into human cell lines (mesenchymal stem cells and human bone cells), which indicates their potential in medicine and biotechnology, is also discussed.

Development of technology for preparing iron oxide pigments

The most widespread inorganic pigments are red iron oxides. Production of red iron oxide pigment based on haematite ores of the Yakovlevskoe deposit is promising and it makes it possible to satisfy the demand for high quality and inexpensive pigment. A waste-free scheme is developed for separating iron ore into two types, i.e., red (pigment) and metallurgical. The technology involves ore crushing, fine grinding in a ball mill and product classification.

Plasma synthesis, Mössbauer spectroscopy and X-ray diffraction studies of nanosized iron oxides

In this article synthesis and study of iron oxide nanopowders are described. The synthesis of sample 1 and sample 2—iron oxides—was carried out by electric arc plasma cutting of ordinary steel. The sample 3 was prepared by evaporation of Fe2O3/FeO mixture in radio-frequency nitrogen plasma. The characterization of the as prepared iron oxide nanoproducts was achieved by means of Mossbauer spectroscopy and X-ray diffraction analysis. The presence of different phases of iron oxide with a basic phase Fe3 − xO4 (magnetite), additional Fe1 − xO (wustite) and α or γ–Fe2O3 (hematite or maghemite) with superparamagnetic particles for sample 1 and sample 2 and Fe3 − xO4 (magnetite) for sample 3 is observed.

SELECTIVE CO OXIDATION

LOW-COORDINATION iron atoms located along the edges of specially prepared iron oxide crystals supported on platinum function as catalytically active sites for carbon monoxide oxidation, according to a study conducted in China ( Science 2010, 328, 1141). The investigation identifies a general principle for designing new types of metal oxide catalysts that might be sufficiently selective and durable for use in fuel cells and other industrial applications. Catalysts based on iron species in low-coordination (or “coordinatively unsaturated”) bonding configurations are known to play key roles in solution-phase and enzyme-mediated oxidation reactions. In those systems, the reactive centers tend to be pinned in place by proteins or various ligands. Similar types of iron assemblies could form the heart of highly active solid-phase catalysts but have been difficult to prepare. Now, scientists at Dalian Institute of Chemical Physics have shown that low-coordination iron species can be synthesized reproducibly along...

Alumina-supported iron oxide nanoparticles as Fischer–Tropsch catalysts: Effect of particle size of iron oxide

The Fischer–Tropsch synthesis of unpromoted and nano-sized iron oxide supported on δ-Al 2O 3 was investigated using a fixed-bed reactor. The catalysts prepared from pre-synthesized iron oxide with varying particle size (2–12 nm) showed much higher catalytic activities than the one prepared by using conventional impregnation method. The best results for CO conversion were obtained when the catalyst had Fe particle size of 6.1 nm. With an increase in particle size, the reduction degree and C 5+ selectivity was increased, whereas CH 4 selectivity and the uptake of adsorbed CO were decreased. Turnover frequency (TOF) at 300 °C was increased from 0.02 to 0.16 s −1 when d(Fe 0) was increased from 2.4 to 6.2 nm, and then it remains almost constant up to a particle size of 11.5 nm. Particle sizes of prepared iron oxide were analyzed by XRD and TEM, and the reduction behaviors of Fe/Al 2O 3 catalysts were studied by H 2-TPR. The effective iron size, metal dispersion and reduction degree of Fe/Al 2O 3 catalysts were measured by CO chemisorption and O 2 titration.

Preparation of Iron-Oxide Coated Porous Ceramics Filter and Adsorption and Degradation on Methylene Blue

The aim of the present work is to obtain iron-oxide coated porous ceramics filter (IOCPCF) via dip-coating and test its adsorption and degradation for methylene blue (MB). Porous ceramics filter (PCF) and ferric nitrate were used as substrate and modifier respectively. IOCPCF was characterized by spectrophotometer, X-ray diffraction, scanning electron microscopy, specific analyzer and Fourier transform infrared spectroscopy. The effect of its structure and performance on adsorption and degradation of MB aqueous solution was investigated. The results indicated that the average pore diameter, specific surface area and porosity of IOCPCF were 11.36 nm, 4.987 m2/g and 58.63% respectively. The major crystalline phase of iron coat was α-Fe2O3 which took on porous framework. Using the prepared material, the decoloration conversion for MB aqueous solution can reach 72.06% in 300min and be increased by 21.59% compared with original PCF.

Preparation of Iron Oxide-Entrapped Chitosan Nanoparticles for Stem Cell Labeling

This study intended to prepare iron oxide nanoparticle-entrapped chitosan (CS) nanoparticles for stem cell labeling. The nanoparticles were synthesized by polymerizing iron oxide nanoparticle-associated methacrylic acid monomer in the presence of CS. TEM revealed that the well-defined iron oxide nanoparticles were successfully encapsulated inside the CS nanoparticles. The effect of CS at different [NH2]/[COOH] molar ratios on particle size, surface charge, thermal stability and magnetic properties was determined systematically. Internalization and localization of the coated nanoparticles were evaluated by atomic absorption spectrometry and confocal laser scanning microscopy. The Kusa O cell line was chosen as a stem cell model. Interestingly, the uptake of iron oxide-entrapped CS nanoparticles was remarkably enhanced under magnetization and the nanoparticles were mostly located inside cellular compartments. It can be concluded that the iron oxide-entrapped CS nanoparticles have a strong potential for stem cell labeling.

Synthesis and Characterization of MRI-Detectable Magnetic Dendritic Nanocarriers

Magnetic nanoparticles have been proposed for use as biomedical purposes to a large extent for several years. In this paper we discuss the preparation and characterization of superparamagnetic iron oxide (Fe3O4) nanoparticles (SPIONs) coated with acetyled – PAMAM dendrimers(Ac-PAMAM). Also, in the present study, the conjugate (Ac-PAMAM)/SPIO nanoparticles were exhaustivly studied as controlled-release systems for parenteral administration of a model drug 5-aminosalicyclic acid (mesalamine) and analyzed using various release kinetic studies. The nanoparticles thus synthesized have been characterized by a Fourier Transform Infrared (FTIR) spectrophotometer and with X-ray diffraction. The morphology of these nanoparticles was studied by scanning electron microscopy (SEM).

Design of iron oxide nanoparticles with different sizes and surface charges for simple and efficient labeling of mesenchymal stem cells

The objective of this study is to prepare iron oxide nanoparticles with different sizes and surface potentials and evaluate the labeling efficiency of bone marrow-derived mesenchymal stem cells (MSC). The ferric and ferrous ions were co-precipitated in the presence of pullulan or the cationized and anionized derivatives to prepare iron oxide-pullulan nanoparticles of a contrast agent of magnetic resonance imaging (MRI). The size and surface potential of iron oxide-pullulan nanoparticles were changed by altering the mixing molar ratio of pullulan OH groups to ferric ions and the mixing percentage of pullulan derivatives, respectively. When MSC were labeled with the iron oxide-pullulan nanoparticles by the co-culture for 1 h, the labeling efficiency and 1H MRI relaxivity were greatly influenced by the particle size and surface potential, while the labeling procedure did not affect the viability and differentiation ability of MSC. These findings indicate that iron oxide-pullulan nanoparticle is a promising tool for the MRI labeling of MSC.

Preparation of titanium oxide, iron oxide, and aluminium oxide from sludge generated from Ti-salt, Fe-salt and Al-salt flocculation of wastewater

In this study, the settled floc (sludge) produced by aluminum sulfate (Al 2(SO 4) 3), ferric chloride (FeCl 3) and titanium tetrachloride (TiCl 4) flocculation was recycled with a novel flocculation process, which has a significant potential to the lower cost of waste disposal, protect the environment and public health and yield economically useful by-products. Three coagulants removed 70% of organic matter in synthetic wastewater. The settled floc was incinerated in the range from 100 °C to 1000 °C. Alumina (Al 2O 3), hematite (Fe 2O 3), titanium oxide (TiO 2) which are the most widely used metal oxides were produced from the wastewater sludge generated by the flocculation in wastewater with Al 2(SO 4) 3, FeCl 3 and TiCl 4, respectively. TiO 2 particles produced from the sludge consisted of the large amount of nano size particles. Hematite (Fe 2O 3) and grattarolaite (Fe 3 (PO 4)O 3 or Fe 3PO 7) included the majority of micro size (40%) particles. Alumina (Al 2O 3) also consisted of micro size (40%). Due to TiO 2 usefulness of the application, detailed characterisation of TiO 2 after calcination at different temperatures were investigated in terms of X-ray diffraction, energy dispersive X-ray, surface area and photoactivity.

Surface modification of iron oxide nanoparticles and their conjuntion with water soluble polymers for biomedical application

Superparamagnetic iron oxide nanoparticles (SPION) coated with suitable bio-compatible substances have been used in biomedicine, particularly in magnetic resonance imaging (MRI), tissue engineering, and hyperthermia and drug delivery. In this study, we describe the synthesis of SPION and its surface modification for in-vitro experiments. The particle diameter and structure were estimated by FESEM, TEM, XRD analyses. The saturation magnetization was characterized. SPION with a mean size of 12 nm have been prepared under N2 atmosphere, with support of natural polymeric starch, by controlling chemical coprecipitation of magnetite phase from aqueous solutions containing suitable salts ratios of Fe2+ and Fe3+. The surface of SPION-nanoparticles was treated with a coordinatable agent for higher dispersion ability in water and remaining the superparamagnetic behavior. The prepared iron oxide nanoparticles were coated with starch, dextran, PEG or MPEG to extend the application potential in the quite different engineering field of nano biomedicine.

Preparation of iron oxides using ammonium iron citrate precursor: Thin films and nanoparticles

Ammonium iron citrate (C 6H 8O 7 · nFe · nH 3N) was used as a precursor for preparing both iron-oxide thin films and nanoparticles. Thin films of iron oxides were fabricated on silicon (111) substrate using a successive-ionic-layer-adsorption-and-reaction (SILAR) method and subsequent hydrothermal or furnace annealing. Atomic force microscopy (AFM) images of the iron-oxide films obtained under various annealing conditions show the changes of the micro-scale surface structures and the magnetic properties. Homogenous Fe 3O 4 nanoparticles around 4 nm in diameter were synthesized by hydrothermal reduction method at low temperature and investigated using transmission electron microscopy (TEM).

Preparation and Characterization of Mesoporous Iron-Oxide

Transition metal oxides are easy to form insoluble oligomer in reaction because of complicated oxidation states,so it is difficult to obtain the desired mesoporous structure.To resolve the problem,mesoporous iron oxide was synthesized by reacting a micellar phase of sodium dodecyl sulfate(SDS) with iron polymer solution which was prepared by controlling the proportion of sodium hydroxide and ferric chloride.Crystal structure and surface structure of the mesoporous iron oxide was characterized by powder X-ray diffraction(XRD),Fourier transform-infrared spectroscopy(FT-IR),thermogravimetric analyse(TGA),Nitrogen adsorption-desorption method and so on.The results show that mesoporous α-Fe2O3 can be obtained after calcining at 450℃ with OH-/Fe3+ ratio of 2.0.Its surface area is 146.5m2·g-1,BJH average diameter is 6.9nm,pore volume is 0.27cm3·g-1.The as-prepared mesoporous iron oxide has better thermal stability,it still has surface area of 110.2m2·g-1 after calcination at 550℃.