Papers by Keyword: Fe₃O₄

Abstract: Iron nitride is a promising material for soft magnetic composite. In the current research, iron nitride compound was produced from natural iron sand, involving coprecipitation and gas nitriding. Prior to coprecipitation, natural iron sands were separated magnetically to obtain pure Fe₃O₄. Afterward, the coprecipitation was carried out to obtain nanosized Fe₃O₄. Gas nitriding of Fe₃O₄ powders was performed at different temperatures i.e. 500 °C, 600 °C and 700 °C, under flowing NH₃ gas. Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) are used to investigate the phases obtained after the nitriding process. XRD patterns of the resulted powder indicate that nitriding temperature at 600 °C and 700 °C can produce iron nitride material, i.e. ε-Fe₃N. While nitriding temperature of 500 °C is not able to yield iron nitrides. SEM examination reveals that the ε-Fe₃N has irregular lamellar morphology. Some impurities are still detected, in the form of Fe₃O₄, Fe₂O₃, Ti₂O₃ and TiO₂. Further works regarding the examination of the magnetic properties of the powders will be carried out.

Abstract: On the one hand, accordingly to remove the surface impurities, we purified the prepared Multi-walled carbon nanotubes (MWCNTs) in our advance experiment; ferrous ions and iron ions in lye through the action of micro-filtration membrane to form smaller size Fe₃O₄ magnetic particles on the other hand. The prepared magnetic Fe₃O₄ with small particle size was loaded on the adorption point of the multi-walled carban nanotubes(MWCNTs) to form magnetic carbon nanocomposites. In order to achieve the best adsorption effect, the preparation temperature was improved in the experiment, and the influence of the ratio of ferrous ions to iron ions on the properties of the material was adjusted. The best adsorption properties of the composites were confirmed by X-ray diffraction and Fourier infrared spectrometer phase analysis. In addition, the application of this experiment to water treatment has a good effect on the copper ion removal.

Abstract: In this work, Fe₃O₄ nanoparticles (NPs) were synthesized using coprecipitation method and TiO₂ NPs were synthesized using sonication method. Fe₃O₄/polyaniline and TiO₂/polyaniline nanocomposites (NCs) were synthesized using polymerization methods. The samples were characterized by X-ray diffractometer, Fourier-transform infrared spectroscopy, and ultraviolet-visible spectroscopy. The results of X-ray diffraction data analysis presented that polyaniline decreased the crystallinity of Fe₃O₄ and TiO₂ NPs. However, the crystal structure of Fe₃O₄ and TiO₂ NPs did not change, which successively formed the cubic spinel and the tetragonal anatase phases. Furthermore, the functional groups of Ti-O-Ti and Fe-O were detected in the wavenumber ranges of 620-580 cm^-1 and 410-520 cm^-1, respectively. The presence of polyaniline was also detected by the emergence of a functional group of polyaniline which also showed that there was an interaction of Fe₃O₄ and TiO₂ NPs with polyaniline. Meanwhile, the results of UV-Vis data analysis showed that the addition of polyaniline decreased the bandgap energy of Fe₃O₄ and TiO₂ NPs significantly from 2.186 to 2.174 eV and from 3.374 to 3.320 eV, respectively.

Abstract: Fe₃O₄ nanoparticles (NPs) have previously been employed in various fields owing to their unique physical and chemical properties. In this paper, Fe₃O₄ NPs are prepared by co-precipitation method in a helical microreactor under different reaction conditions which affect the size of Fe₃O₄ NPs. The product is characterized by FT-IR and XPS. Also, VSM characterization shows that Fe₃O₄ exhibits typical superparamagnetic behavior and the saturation magnetization of NPs is 53 emu/g.

Abstract: The size effect of magnetic nanoparticles provides a various magnetic characteristic as a change of domain size. We report, synthesis of core-shell iron oxide and magnetic properties. Iron oxide particles were synthesized by co-precipitation method of iron (III) FeCl₃.6H₂O, iron (II) FeCl₂.4H₂O, in the mixture of with or without TEOS to investigated the physical properties. From XRD measurement, it was observed that all iron oxide particles with or without mixture of SiO₂ has a hematite phase of a-Fe₂O₃. From M-H loop measurement, it was observed that the iron oxide without SiO₂ has a ferromagnetic characteristic, while the iron oxide with SiO₂ showed a medium state as a contribution of superparamagnetic and ferromagnetic properties.

Abstract: Fe₃O₄/Carboxymethyl Cellulose (CMC)/Polyvinyl Alcohol (PVA) hydrogel magnetic was successfully synthesized by using the freezing-thawing process. Meanwhile, the filler of Fe₃O₄ nanoparticles was successfully fabricated by co-precipitation method. Magnetic hydrogel and Fe₃O₄ was revealed by using X-Ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), Vibrating Sample Magnetometer (VSM), and Small Angle X-ray Scattering (SAXS) to investigate the content of elements in the Fe₃O₄ filler, the functional group network of samples, magnetic properties of magnetic hydrogel and Fe₃O₄, and nanostructure of magnetic hydrogel, respectively. The magnetic properties of magnetic hydrogel decreased as the decrease in the particle sizes of the Fe₃O₄ nanoparticles. On the other hand, the saturation magnetization of magnetic hydrogel decreased as the freezing-thawing route increased in number. This condition can be concluded that the distribution of the Fe₃O₄ filler in CMC/PVA magnetic hydrogel was more effective when the route number of freezing-thawing reached the maximum process (7x processes). Moreover, the nanostructure of magnetic hydrogel revealed the composition of the crystalline phase of CMC/PVA hydrogel of approximately 6 nm. By these characteristics, Fe₃O₄/CMC/PVA magnetic hydrogel is potential to be used as smart gel such as artificial muscle, switch-of, and the others.

Abstract: Fe₃O₄/SiO₂/TiO₂ dopped Cu with magnetic properties had been succesfully syntesized and characterized. The research was began with the synthesis of magnetite and magnetite covered by silica by co-precipitation and sonication method, and the preparation of Cu-doped TiO₂ using sol-gel method followed by calcination. The concentrations of Cu were 0%, 1%, 3%, 5%, and 7% (FST0, FST1, FST3, FST5, and FST7). The Fourier Transform Infra Red spectrophotometer (FTIR), X-Ray Diffractometer (XRD), Scanning Electron Microscope-Energy Dispersive X-ray spectrophotometer (SEM-EDX), UV-Specular Reflectance Spectrophotometer (SR-UV), and Transmission Electron Microscope (TEM) were used to characterize the nanocomposite and external magnetic bar was used to separate the nanocomposite in an aqueous media. The Cu concentration affected the band gap energy (Eg) and the optimum result was 2.832 eV in FST7. The best magnetic propertieswas material FST0. The time needed for separate this material with aqueous medium was 372 second.

Abstract: Monodisperse nanoparticles are materials that are not agglomerate. The good characteristic of these materials is the dispersity in water, so they can better react with target pollutants. Accordingly, in this work, the monodisperse magnetite nanoparticles with the superparamagnetic property were synthesized and characterized. The hydrothermal method with the iron compound and polymer as precursors was conducted. The magnetic nanoparticles were characterized by several techniques including X-ray diffraction, field emission scanning electron microscope, transmission electron microscope, and vibrating sample magnetometer. The saturation magnetization (Ms) value, the coercivity (Hc), and the retentivity (Mr) were measured to demonstrate the paramagnetic behavior of the monodisperse magnetite nanoparticles. The results showed that the Fe₃O₄ nanoparticle were obtained at 200 °C for 16 h. The particles are monodispersed with the size approximately in the range of 60 - 250 nm as confirmed by FE-SEM and TEM images. These are the single grain and had the spherical shape similar to a blackberry. The saturation magnetization of 17.287 emu/g and ratio of retentivity to saturation magnetization (Mr/Ms) characterized the squareness of the hysteresis loops was 0.03653. It can be indicated that the Fe₃O₄ nanoparticles had superparamagnetic behavior. This property of Fe₃O₄ nanoparticles can draw pollutants to absorb on the surface of these nanomaterials. Then adsorbed pollutants can be easily removed by separating the Fe₃O₄ materials from water. This technique can be applied further in water treatment and pollutant removal.

Abstract: Magnetic heterogeneous Fe₃O₄/TiO₂/CuO catalyst were synthesized using sol-gel method. The molar ratio of Fe₃O₄/TiO₂/CuO were varied from 1:1:0.1 until 1:1:5. The all synthesized catalyst were characterized using X-ray Diffraction (XRD), Energy Dispersive X-ray (EDX), Field Emission Scanning Electron Microscope (FE-SEM), and Vibrating Sample Magnetometer (VSM). The result show that the magnetic heterogeneous Fe₃O₄/TiO₂/CuO catalyst exhibit ferromagnetic behavior under room temperature. The catalytic performance were evaluated on the degradation of methylene blue under UV light and combination of ultrasound and UV-light Irradiation. The combination of ultrasound and UV-light irradiation exhibit batter catalytic performance than ultrasound irradiation only. The Magnetic heterogeneous Fe₃O₄/TiO₂/CuO with molar ratio 1:1:0.1 shows highest catalytic performance. The reusability of catalyst were also observed.

Abstract: Based on the preparation of polyacrylamide/clays lithium magnesium silicate hydrate (PAAm/LMSH, abbreviated as AP) nanocomposite hydrogel by in-situ free radical polymerization, Fe₃O₄ nanoparticles were introduced by chemical co-precipitation method, to form magnetic Fe₃O₄/PAAm/LMSH (abbreviated as MAP) nanocomposite hydrogel. With ESEM, XRD, and TGA technologies, the structures of MAP nanocomposite hydrogel and Fe₃O₄ nanoparticles formed. Magnetic characteristic of MAP nanocomposite hydrogel was characterized by VSM. The tensile test with Universal Testing Machine was employed for mechanical properties. Furthermore, taking cationic dye Crystal Violet (CV) and anionic dye Methyl Orange (MO) for example, the adsorption properties of MAP nanocomposite hydrogel were analyzed with UV-visible spectrophotometer method. The results show that MAP nanocomposite hydrogel had strong superparamagnetic properties. The introduced Fe₃O₄ magnetic particles illustrated spinel structure, and nanoparticle size of 8.52 nm. The swelling rate of MAP sample was up to 30.542, showing excellent swelling ability. Compared with AP nanocomposite hydrogel, MAP nanocomposite hydrogel had stronger mechanical strength with the tensile stress of 0.39MPa. Adsorption experiments indicated that MAP nanocomposite hydrogel had favorable adsorption properties on CV with removal rate of 97.6%, 1.27 times that of AP nanocomposite hydrogel. The conclusions confirm the application prospect of MAP nanocomposite hydrogel as dye adsorbent in textile printing and dyeing wastewater treatment.