Papers by Keyword: Fe₃O₄ Nanoparticles

Abstract: The magnetic properties of magnetite nanoparticles (Fe₃O₄ NPs) are being investigated. Fe₃O₄ NPs were prepared using the co-precipitation method and oven dried. The magnetic properties are influenced by the electron environments of the Fe³⁺ ions within the iron oxide structure. XPS spectra of Fe³⁺ (2p_3/2) and (2p_1/2) show peaks around 706.45 eV and 720.76 eV, respectively. Furthermore, magnetite NPs dried at 60 °C exhibited the largest hysteresis loop at 50K and less at 300K. In addition, the values of Ms and Mr indicate ferromagnetic behavior in Fe₃O₄ NPs. The result of this material shows high Ms (~38.638 emu/g) at 50K with Hc of 3.094K (near ferromagnetism) and ~33.843 emu/g at 300K with Hc of 0.000K (superparamagnetic). However, these magnetic properties are utilized for biomaterial applications such as separating biomolecules or coating core shells for nanoparticles, which presents an option for future biomedical technology.

Abstract: The aim of this study was to compare the synthesis process of magnetic silica nanoparticles (Fe-SNP) through the analysis of X-ray Diffraction (XRD) results. Fe₃O₄ magnetic nanopowders was synthesized by ultrasonic assisted co-precipitation and Fe-SNP was synthesized by direct mixing method of sodium silicate (Na₂SiO₃) and magnetite (Fe₃O₄) and the sol-gel method. Silica sludge was used as a silica source from Indonesia geothermal power plant waste. The synthesized of Fe-SNP is the functionalization of Fe₃O₄ with silica. Variations concentration of Na₂SiO₃ is used for the direct mixing method and variations of Fe₃O₄ form is used for the sol-gel method. Particles formed and particle size were characterized by XRD. The XRD results showed that there is no SiO₂ phase in the sample synthesized by direct mixing method while two phases of SiO₂ and Fe₃O₄ were found in the sample synthesized by sol-gel method. The size of the Fe₃O₄ nanoparticles calculated with Scherer’s formula and it obtained 19.9 nm, while the Fe₃O₄ nanoparticles with the addition of 20 mL and 6 mL Na₂SiO₃ concentrations were 6,53 nm and 10,23 nm. For the sol-gel method the size of Fe₃O₄ nanoparticles obtained was 11,03 using Fe₃O₄ powders and 9,86 using Fe₃O₄ solutions.

Abstract: There are many methods for synthesizing magnetite nanoparticles. Most methods take a long time, and the result is undesirable. In this paper a green method was used to synthesize nanoparticles because it takes a short time and is both straightforward and eco-friendly. It is done by adding : =1:2 molar ratio solution with different amounts of extract and different amounts of NaOH solution for 20 min at different temperatures, in hotplate stirrers, to control their relative size. UV-Vis spectroscopy, vibrating sample magnetometer technique (VSM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to characterize the magnetite nanoparticles. The result confirms that the changes in amounts of NaOH and extract led to a change in the pH of a solution and that the increase in amounts of the extract caused the low addition of NaOH. These changes influenced the process of synthesis and characterization. The Uv-vis analysis confirms that the surface plasmon resonance had a highly visible brad peak in the 290–460 nm range, as well as a peak shift to shorter wavelengths (blue shift) with a pH change and a peak shift to longer wavelengths (red shift) with a temperature change. TEM imaging confirms that all the synthesized had a spherical shape with size changed according to a parameter change of within 40–9 nm. Magnetic analysis showed the magnetite nanoparticles synthesized have smaller sizes and are superparamagnetic with the influence of particle size on the magnetic properties, including Hc, Ms, and Mr.

Abstract: In this study, a simple one-step synthetic approach using lotus seed pods and iron(III) chloride has been developed to prepare Fe₃O₄ nanoparticles loaded activated carbon composite (Fe₃O₄-NPs/AC) for removal of Ni(II) ions from aqueous solution. The physical and chemical characteristics of Fe₃O₄-NPs/AC were comprehensively analyzed by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and Brunauer–Emmett–Teller analysis. On account of the combined advantages of lotus seed pod carbon and Fe₃O₄ nanoparticles, the Fe₃O₄-NPs/AC showed excellent adsorption efficiency for Ni(II) ions with the maximum adsorption capacity of 50.72 mg g^-1 at optimal conditions (pH of 6, contact time of 60 min, 25 °C, and adsorbent dosage of 4.0 g L^-1). It was found that the adsorption process of Ni(II) on Fe₃O₄-NPs/AC was feasible, spontaneous and endothermic, and was well described by the Langmuir isotherm model and pseudo-first-order kinetic equation. The Fe₃O₄-NPs/AC composite also showed good reusability with removal efficiency of greater than 86.25% after five cycles of reuse.

Abstract: Polyurethane has a wide range of chemical structures available led to the design of materials that easily can meet requirements to shape memory polyurethane (SMPU) due to its ability to retain its shape after deformation through giving a certain disturbance like magnetic field. Based on the previous study, polyurethanes synthesized by reacting 4,4’-methylenebis (cyclohexyl isocyanate) to poly(ethylene glycol) Mw: 6000 as polyurethane chain with 1,1,1-trimethylol propane as chain extender, is a potential candidate for shape memory polyurethane (SMPU). Furthermore this study was performed by adding Fe₃O₄ nanoparticles as a filler to provide magnetic behavior. In this study, The magnetic and mechanical properties of the SMPU after adding Fe₃O₄ nanoparticles were evaluated by observing compatibility between the filler and matrix, morphology, ability in retaining shape, and mechanical properties through measuring FTIR, FESEM, Vibrating Magnetometer and UTM, respectively. This study reported a good compatibility between Fe₃O₄ and the polyurethane, and lack agglomeration of Fe₃O₄ nanoparticles indicated FTIR and FESEM-EDAX, the fastest ability on retaining its shape obtained from materials with lowest Fe₃O₄ (3 wt%). Meanwhile the best mechanical and magnetic was resulted from adding 11 wt% of Fe₃O₄

Abstract: The superparamagnetic graphene nanosheets–Fe₃O₄ nanoparticles (GNs–Fe₃O₄) hybrid has been successfully prepared via an easy and scalable chemical precipitation method. The inductive heat property of GNs–Fe₃O₄ hybrid in an alternating current (AC) magnetic field was investigated. The potential of GNs–Fe₃O₄ hybrid was evaluated for localized hyperthermia treatment of cancers. The GNs–Fe₃O₄ hybrid exhibits a superparamagnetic behavior, its specific saturation magnetization, Ms is 66.963 emu g^-1. After exposed in the AC magnetic field for 1140 sec, the temperature of physiological saline suspension containing GNS–Fe₃O₄ hybrid were 81 oC. The GNs–Fe₃O₄ hybrid will be useful as good thermoseeds for localized hyperthermia treatment of cancers.

Abstract: Magnetite (Fe₃O₄) nanoparticles were successfully synthesized by ascorbic acid mediated reduction of Fe (acac)₃, without using any intentionally added capping agent. Fine tuning of synthesis parameters such as dropping rate of ascorbic acid solution, addition temperature, reflux temperature and time, and concentration of reactants have yielded nanoparticles of size 15±4 nm. Synthesis is observed to be highly reproducible. Possible mechanism for growth of Fe₃O₄ nanoparticles is suggested. Nanoparticles are characterized for their size, crystallinity and crystal structure, elemental analysis for impurities (if any), and presence of any additional oxide phases – by SEM and TEM, XRD, EDAX and XPS spectroscopy, respectively.

Abstract:

The effects of gamma ray irradiation on high temperature superconductors YBa₂Cu₃O_7-δ with nano particles Fe₃O₄ (20-30 nm) addition were investigated. YBCO superconductor powders were prepared by using high purity oxide powders via solid state reaction method. 0.01 – 0.05 wt.% of nano particles were added into YBCO. Samples were irradiated with 100 kGy gamma ray. The critical temperature (T_c) and transport critical current density (J_c) were determined by using four point probe method. The lattice parameters and morphology of the samples were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. The results before and after gamma ray irradiation were compared. All of the samples showed increased T_c-zero after 100 kGy gamma ray irradiation. However, the J_c was degraded after gamma ray irradiation. There is no significant variation found in the XRD patterns. The porosity of the samples was increased by the gamma ray irradiation. It can be concluded that gamma ray irradiation has enhanced the superconducting properties but degraded the transport properties.

Abstract: The preparation of magnetite nanoparticles with controlled size has attracted of scientific and technological broad attention. Spherical magnetite nanoparticles in the size range from 8nm to 22 nm were synthesized by coprecipiation method using hexadecyl trimethyl ammonium bromide (CTAB) as dispersant. Magnetite nanoparticles have good dispersibility and uniform particles size distribution. The properties were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), automated surface area and pore size analyzer, vibrating sample magnetometer (VSM) and the catalytic performance was measured using high performance liquid chromatography (HPLC). The saturation magnetization is 13.785emu/g, and the coercive force of the sample is 23.738G, the average size of the particles is 13.6 nm, specific surface area is 19.318 m²/g and phenol conversion is up to 99.5%. These results indicate the synthesized magnetite particles have good performance.

Abstract: The experiments of TOC and UV₂₅₄ removal of humic acid (HA) solution by ultrasound (US) irradiation with the presence of H₂O₂ and Fe₃O₄ nanoparticles (NP) were carried out. The comparison of enhancement effect of humic acid sonolysis by H₂O₂ and NP was investigated. It was found that removal efficiency of TOC and UV₂₅₄ increased significantly in the order of US< US/NP< US/H₂O₂< NP/H₂O₂< US/NP/H₂O₂. During US/NP/H₂O₂ combining process, the contribution of H₂O₂ should be presenting most OH radicals for humic acid degradation, Fe₃O₄ nanoparticles would supply adsorption surface for humic acid to have more chance to be oxidized, and ultrasonic would work as main energy for OH radicals generation and offer sonochemical environment.