Magnetic Iron Oxide Particles Research Articles

Three-dimensional network constructed by vertically oriented multilayer graphene and SiC nanowires for improving thermal conductivity and operating safety of epoxy composites with ultralow loading

The oriented graphene could construct an effective heat transfer path in composites with low filler loading. However, electrical conductivity and hygroscopicity caused by functionalized graphene has been ignored, which would decay the lifetime of power devices with the composites as thermal managing materials. In this work, SiC nanowires with high thermal conductivity and hydrophobicity were introduced into vertically oriented multilayer graphene in epoxy resin, constructing an effectively thermally conductive structure. In the structure, multilayer graphene coated with magnetic iron oxide particles responded to external magnetic field, which dramatically reduced the multilayer graphene loading in epoxy resin. When the fillers were rearranged by the magnetic field, the thermal conductivity of the composites reached 0.708 W/(mK), an enhancement of 311.6% compared to epoxy resin. Furthermore, SiC nanowires also damped the electrical conductivity (1.54 × 10−13 S/cm) and hygroscopicity of epoxy composites. The design made it possible for the composites to be applied to electronic packaging field.

Experimental investigation of organic fouling mitigation in membrane filtration and removal by magnetic iron oxide particles

Here magnetic iron oxide particles (MIOPs) were synthesized under atmospheric air and which size was controlled by regulating the flow rate of alkali addition and used for efficient removal of bovine serum albumin (BSA) from water. The MIOPs were characterized using field-emission scanning electron microscopy (FE-SEM), Fourier transformation-Infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). The results revealed a successful preparation of the MIOPs. The removal efficiency for BSA using MIOPs was found to be about 100% at lower concentrations (≥ 10 mg/L). The maximum adsorption of 64.7 mg/g for BSA was achieved as per the Langmuir adsorption model. In addition, microfiltration membrane for removal of BSA as model protein organic foulant is also studied. The effect of various MIOPs adsorbent sizes of 210, 680 and 1130 nm on the absorption capacity of BSA was investigated. Water permeability of the BSA integrated with the smallest size MIOPs membrane was increased by approximately 22% compared by the neat BSA membrane during dead-end filtration. Furthermore, the presence of small size MIOPs were also effective in increasing the permeate flux.

Destruction of Epoxy-Based Composite Materials under the Influence of Impact Load

Some features of impact destruction are shown on the example of a composite material with epoxy matrix and hybrid filler, magnetic particles of iron oxide of micron size and nanoparticles of iron oxide are used in the capacity of it. Dependence of the impact viscosity of the material on the temperature was discovered experimentally, which demonstrates the increase of this value at the decrease of the temperature.

Magnetic iron oxide particles (Fe3O4) fabricated by ball milling for improving the environmental quality

Nowadays magnetic iron oxide particles (Fe3O4) have been extensively used as nanomaterials due to their broad range of applications. One of their applications is to improve the environmental quality by elimination of harmful pollutants in wastewater. Therefore, preparation method of magnetite (Fe3O4) nanoparticles is one of the most important keys to its adsorption efficiency. This study aims to prepare magnetite nanoparticles from natural iron sand of Arta Beach, Pariaman, West Sumatera using ball milling technique. This technique is simple and easy to carry out. The balls used in this milling are the iron balls with the diameter of 1.5 cm. The phase composition, elemental composition, microstructure and magnetic properties of milled powder of magnetic particles were studied by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) respectively. The results showed that the milling time is a key parameter of the magnetite nanoparticles preparation. By increasing the milling time, then high purity magnetite samples can be obtained. Moreover, the magnetic particle size of the sample decreases as the milling time increases. The SEM micrographs showed that the sample has a broad distribution of particle diameters, ranging from around 1 up to 107 μm and 0.5 to 36 μm after 30 and 90 hours of milling respectively.

Development of a ternerry condunting composite (PPy/Au/CNT@Fe3O4) immobilized FRT/GOD bioanode for glucose/oxygen biofuel cell applications

Enzymatic biofuel cells (EBFCs) are considered as a promising technology to sustain the requirements of miniaturized portable energy sources. Electrode materials being one of the substantial aspects of EBFCs have stimulated immense interest in research. A new platform made of nanocomposite, involving magnetic particles of iron oxide (Fe3O4), carbon nanotubes (CNT), gold nanoparticles (Au) and a conducting polymer polypyrrole (PPy), was used as the electrode support for the immobilization of glucose oxidase (GOD) which improves the bioelectrocatalysis of the enzyme towards oxidation of glucose. The structural and electrochemical characterization of the modified bioanode GCE/PPy/Au/CNT@Fe3O4/FRT/GOD was performed using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). The performance of the bioanode was evaluated with promising results showing the maximum current density of 6.01 mA cm−2 (0.22 V vs. Ag/AgCl) in 40 mM of glucose concentration at 0.38 V open circuit potential (OCV). The results suggested that PPy/Au/CNT@Fe3O4 nanocomposite significantly improve the surface area of the electrode and served as a suitable environment for enzyme immobilization, and established good electrical communication by facilitating electron transfer between enzymes and electrode surface. The as-synthesized composite has been inferred as a promising platform for improved bioelectrocatalysis owing to the excellent combination of superparamagnetism of Fe3O4 with good electrocatalytic properties of CNT, PPy, and Au nanoparticles. Thus PPy/Au/CNT@Fe3O4 nanocomposite can be considered as a prospective electrode material for developing better electrochemical biosensors and biofuel cell anode.

Magnetic Particles: Their Applications from Sample Preparations to Biosensing Platforms.

The growing interest in magnetic materials as a universal tool has been shown by an increasing number of scientific publications regarding magnetic materials and its various applications. Substantial progress has been recently made on the synthesis of magnetic iron oxide particles in terms of size, chemical composition, and surface chemistry. In addition, surface layers of polymers, silica, biomolecules, etc., on magnetic particles, can be modified to obtain affinity to target molecules. The developed magnetic iron oxide particles have been significantly utilized for diagnostic applications, such as sample preparations and biosensing platforms, leading to the selectivity and sensitivity against target molecules and the ease of use in the sensing systems. For the process of sample preparations, the magnetic particles do assist in target isolation from biological environments, having non-specific molecules and undesired molecules. Moreover, the magnetic particles can be easily applied for various methods of biosensing devices, such as optical, electrochemical, and magnetic phenomena-based methods, and also any methods combined with microfluidic systems. Here we review the utilization of magnetic materials in the isolation/preconcentration of various molecules and cells, and their use in various techniques for diagnostic biosensors that may greatly contribute to future innovation in point-of-care and high-throughput automation systems.

Enhancing the Low-Frequency Induction Heating Effect of Magnetic Composites for Medical Applications.

This study aims to enhance the low-frequency induction heating (LFIH) effect in a thermoplastic polymer doped with iron oxide magnetic particles, which are promising candidates for several medical applications thanks to their confirmed biocompatibility. Two main approaches were proposed to successfully boost the heating ability; i.e., improving the magnetic concentration of the composite with higher filler content of 30 wt %, and doubling the frequency excitation after optimization of the inductor design. To test the magnetic properties of the ferromagnetic composite, a measurement of permeability as a function of temperature, frequency, and particle content was carried out. Thermal transfer based COMSOL simulations together with experimental tests have been performed, demonstrating feasibility of the proposed approach to significantly enhance the target temperature in a magnetic composite. These results are encouraging and confirmed that IH can be exploited in medical applications, especially for the treatment of varicose veins where local heating remains a true challenge.

Magnetic assisted separation of uranium(VI) from aqueous phase using diethylenetriamine modified high capacity iron oxide adsorbent

Processing of uranium ore for the production of reactor-grade uranium results in the generation of large amount of aqueous waste containing small quantities of uranium, but higher than the guideline value (15 μg L−1) recommended by World Health Organization (WHO). The presence of uranium in aqueous waste poses several hazards and environmental issues due to the radioactive nature and migration behavior of uranium in the geosphere. In order to remove uranium (VI) from aqueous waste, the diethylenetriamine modified high capacity magnetic iron oxide adsorbent, abbreviated as Fe-DETA, was prepared and studied for the extraction of uranium from aqueous solutions. The Fe-DETA was characterized by X-ray diffraction, thermal analysis, infrared and Raman spectroscopy, and scanning electron microscopy. Significantly high amount (2 mmol g−1) of diethylenetriamine functional group (DETA) was anchored on magnetic iron oxide particles. The extraction of U(VI) from aqueous phase was studied as a function of pH of the aqueous phase, duration of the contact between Fe-DETA and aqueous phase, concentration of U(VI) in aqueous solution etc. The data on the rate of extraction of U(VI) in Fe-DETA was fitted into the first order and second order rate equations. The apparent uranium extraction capacity on Fe-DETA was determined to be 236 mg g−1, which correspond to the formation of 1:2 complex of U(VI) to diethylenetriamine ligand in Fe-DETA phase. The loaded U(VI) in Fe-DETA was quantitatively recovered using dilute Na2CO3 solution, and the recovered Fe-DETA was recycled for further extraction of U(VI), without any change in the apparent U(VI) extraction capacity.

Testing Different Polymers and Boron Nitride Nanotube Properties in Fabrication of Ion-selective Membranes

One largely untapped source of clean energy is the use of osmotic gradients where freshwater and saltwater are mixed, for example at estuaries. To harness such energy, charge-selective membranes are needed to separate the anions and cations in saltwater, establishing an electric potential like a battery. The objective of this study was twofold: to investigate the creation of the polymer matrix and test the properties of boron nitride nanotubes, as both are essential in the creation of an ion-selective membrane. The proposed polymer layer has many attractive properties: controllable thickness allowing nanotubes (typically 5-10 microns long) to pass through, being rapidly curable with a UV lamp, easy mounting on other substrates, resistance to O2 and SF6 plasma gas etching, and structural strength to prevent tears. The hypotheses for this study are that the Soltech 704 (SU704) will prove to be the best polymer in terms of both etching and curing results, in addition, the relationship between the magnetic dipole moment and the length of the nanotubes is predicted to be linear. The Soltech 704 is trifunctional, compared to the other difunctional polymers tested, which is why it is predicted to have the highest strength. The dipole moment was hypothesized to be linear with nanotube length, since a longer nanotube allows for more iron oxide particles to attach to it. Out of three polymer samples tested in this study, the mixture known as Soltech 704 showed the best resistance to etching, as well as the highest UV cure rate. These two traits are desirable since they lead to a sturdier membrane and one that is created more quickly. To allow such nanotubes to be aligned, we attached magnetic iron oxide particles and then applied a magnetic field. We then recorded the magnetic dipole moments of nanotubes and compared it to the length of the nanotube. The relationship between dipole moment and length can thus be discovered. Such results can be used to optimize the alignment procedure for the nanotubes, as well as the procedure for curing the polymer.

Dopamine Loaded SiO2 Coated Fe3O4 Magnetic Nanoparticles: A New Anticancer Agent in pH‐Dependent Drug Delivery

AbstractIn this present study, we have shown dopamine acts as very good agent in killing cancer cells with very high rate. We have used silica coated iron oxide magnetic particles as dopamine drug delivery agent. We have synthesized iron oxide (Fe3O4) magnetic nanoparticles (MNPs), and coated it with silicon dioxide (SiO2), then loaded it with dopamine (DA) which has been used here as anticancer drug. Here a significant improvement was found in case of drug release under acidic pH than normal blood pH. The MNPs are characterized using X‐ray diffraction (XRD), Energy Dispersive Analysis of X‐rays (EDAX), Fourier transform infrared (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM), Selected Area Electron Diffraction (SAED) and vibrating sample magnetometer (VSM) to confirm its structural, morphological and magnetic properties. Particles after characterization were involved in investigation of DA drug release by altering pH for better treatment of cancer. The results are very important and promising.

3D printed polylactic acid nanocomposite scaffolds for tissue engineering applications

In this study, biodegradable polylactic acid (PLA) and PLA nanocomposite scaffolds reinforced with magnetic and conductive fillers, were processed via fused filament fabrication additive manufacturing and their bioactivity and biodegradation characteristics were examined. Porous 3D architectures with 50% bulk porosity were 3D printed, and their physicochemical properties were evaluated. Thermal analysis confirmed the presence of ~18 wt% of carbon nanostructures (CNF and GNP; nowonwards CNF) and ~37 wt% of magnetic iron oxide (Fe2O3) particles in the filaments. The in vitro degradation tests of scaffolds showed porous and fractured struts after 2 and 4 weeks of immersion in DMEM respectively, although a negligible weight loss is observed. Greater extent of degradation is observed in PLA with magnetic fillers followed by PLA with conductive fillers and neat PLA. In vitro bioactivity study of scaffolds indicate enhancement from ~2.9% (PLA) to ~5.32% (PLA/CNF) and ~ 3.12% (PLA/Fe2O3). Stiffness calculated from the compression tests showed decrease from ~680 MPa (PLA) to 533 MPa and 425 MPa for PLA/CNF and PLA/Fe2O3 respectively. Enhanced bioactivity and faster biodegradation response of PLA nanocomposites with conductive fillers make them a potential candidate for tissue engineering applications such as scaffold bone replacement and regeneration.

Removal of Bisphenol A Using Magnetically Responsive Spruce Chip Biochar

AbstractBisphenol A was efficiently adsorbed on biochar magnetically modified with microwave‐synthesized magnetic iron oxide particles. The adsorption followed the Langmuir isotherm model, and the maximum adsorption capacity was 77.4 mg per gram of magnetic biochar at 282.15 K. Kinetics of sorption process followed the pseudo‐second‐order kinetic model, and thermodynamic studies described an exothermic and spontaneous adsorption process. The prepared material exhibited high adsorption of bisphenol A and a rapid magnetic response to an external magnetic field.

Electroactive Composites with Block Copolymer-Templated Iron Oxide Nanoparticles for Magnetic Hyperthermia Application.

Cancer has been one of the leading causes of human death for centuries. Magnetic hyperthermia is a promising technique to confine and control cancers. However, particles used in magnetic hyperthermia leaking from where the cancers are located could compromise human health. Therefore, we developed electroactive iron oxide/block copolymer composites to tackle the leakage problem. Experimental results show that oleylamine-modified magnetic iron oxide (Fe3O4) particles and electroactive tetraaniline (TA) could be templated in the self-assembled microstructures of sulfonated [styrene-b-(ethylene-ran-butylene)-b-styrene] (S-SEBS) block copolymers. Various amounts of Fe3O4 particles and TA oligomer were incorporated in S-SEBS block copolymer and their electroactive behavior was confirmed by exhibiting two pairs of well-defined anodic and cathodic current peaks in cyclic voltammetry tests. The heating performance of the resultant TA/Fe3O4/polymer composites improved on increasing the added amount of Fe3O4 particles and TA oligomers. Both Fe3O4 and TA can contribute to improved heating performance, but Fe3O4 possesses a greater contribution than TA does. Hence, the main source for increasing the composites’ temperature is Neel relaxation loss from Fe3O4 magnetic particles.

Octylamine as a novel fuel for the preparation of magnetic iron oxide particles by an aqueous auto–ignition method

Magnetic particles were successfully synthesised by a new and simple one-step auto-ignition method, with octylamine as organic fuel and iron nitrate nonahydrate as an oxidant, both in an aqueous solution. After synthesis and stabilising at 550 °C in reduced atmosphere, the samples consisted of mostly well crystalline magnetite (Fe3O4), with a small amount of hematite present, in the form of micron–scale agglomerations of nanoparticles. A noticeable reduction of crystallite size of magnetite (42–28 nm) and an increase in the hematite crystallite sizes were observed with increasing octylamine addition, although the actual observed nanoparticle size increased slightly from ∼30 up to 50 nm. The magnetic properties were assessed at room temperature, and all were found to be strongly ferrimagnetic with very narrow hysteresis loops. The saturation magnetisation at 4 T was 77.2–91.6 A m2 kg−1, and coercivity was only 10.03–11.30 kA m−1 (126–142 Oe). These results are also compared to the few previous studies on using octylamine to produce magnetite nanoparticles, which were all purely organic hydrothermal processes, and produced materials with lower magnetisation values and comparable coercivity in similarly sized particles.

Synthesis and optimization of reaction variables in the preparation of pine-magnetite composite for removal of methylene blue dye

Purity and quality of water is a basic concern to mankind. The environment is deteriorating daily due to industrial pollution. Dyes discharged together with industrial textile wastewaters are main organic pollutants because they are highly visible and undesirable even at low concentrations in water. Natural biomaterials have been applied previously as adsorbents for dyes from aqueous solution, but their application has been limited by low adsorption capacity. In this study, pine cone biomass, a naturally occurring agricultural waste was treated with 0.15 M NaOH solution to remove unwanted plant extracts and iron oxide magnetic particles which was coated on the pine surface. The main focus of the study was to prepare and optimize the working conditions for the pine magnetite composite. The bionanocomposite material was synthesized by a complete co-precipitation method of Fe2+: Fe3+ (1:2) under alkaline conditions in an inert environment followed by addition of the biomass. The variables used for the experiments were volume of NH4OH varied from 5 to 40 ml, reaction temperature varied from 40 to 100 °C, effect of time varied from 15 to 60 min and mass from 1.0 to 3.5 g. Incorporation of magnetite nanoparticles onto the surface of the biomass was confirmed by FTIR, TGA and XRD. TEM showed particles size ranging from 8.23–11.73 nm. XRF showed the iron oxide content ranging from 57 to 74%.

Solvothermal Synthesis and Characterization of Magnetic Bamboo Charcoal (BC) Nanocomposites

In this paper the synthesis of magnetic bamboo charcoal–iron oxide (BC/Fe) nanocomposites from raw bamboo (Phyllostachys pubescens) by the solvothermal process is presented. In the first step, bamboo charcoal was prepared from raw bamboo in an oven at a temperature of 800 °C. In the second step, a carbon matrix of iron oxide magnetic nanoparticles was prepared by the solvothermal process. Ferric nitrate was the iron precursor, and ethylene glycol and other solvents were the reducing agents. The effect of various process parameters such as molar ratio of BC to Fe, reduction temperature, solvents and duration of reaction on the size, shape and amount of produced magnetic iron oxide particles were reported. The reduction temperature, time and selection of solvent were the most critical parameters. XRD analysis showed the presence of magnetite, along with humboldtine particles, on the bamboo charcoal (BC) with an average size range of 12.7 nm to 29.3 nm.

Externally Controlled Cellular Transport of Magnetic Iron Oxide Particles with Polysaccharide Surface Coatings

Recently, due to their promising applications in biomedicine, magnetic iron oxide nanoparticles (MPs) have become one of the research hotspots in the nanomedicine field. Since various synthetic modifications have been widely applied to these nanoparticles for better targeting behaviors, it is meaningful to apply the optimal magnetic field condition for each case. This will enable creating a safe and efficient drug targeting using different types of MPs. In the present study, we aimed to find out any changes of transepithelial transport of polysaccharide-coated MPs by applying the continuous or the pulsatile magnetic field condition. Our results with heparin-functionalized MPs indicate that the particle concentrations and the external magnetic field could influence the transepithelial permeability of the particles. In the presence of a continuously applied magnetic density, heparin-MPs at high concentrations, by forming magnetically-induced aggregation of particles over the cell surface layer, showed a lower cellular transport than those at low concentrations. Furthermore, the results from the quantitative chemical assays and imaging analyses showed that transepithelial transport of heparin-MPs (negatively charged) under the pulsatile magnetic field was higher than that under the continuous magnetic field (CP), whereas the starch-MPs (neutrally charged) showed a small difference in transepithelial transport or cell retention between pulsatile vs. continuous magnetic field conditions. Taken together, our results suggest that the external magnetic field should be differentially applied to control the cellular drug transport depending on the physicochemical properties of the surface chemistry of magnetic particles.

Induction heating-based low-frequency alternating magnetic field: High potential of ferromagnetic composites for medical applications

This study focusses on a low-frequency induction heating (LFIH) effect in a thermoplastic polymer (acrylonitrile butadiene styrene, ABS) filled with iron oxide magnetic particles. The LFIH effect in such ferromagnetic composites appears as soon as the sample is exposed to an alternating magnetic excitation field and is mainly due to the so-called “microscopic” eddy currents linked to the motions of the magnetic domain wall. To generate an AC magnetic field with significant amplitude under a low-frequency range of a few thousand Hz, a specific test bench has been designed using a rotating motor and strong permanent magnets. Theoretical hysteresis modeling, together with thermal transfer based Comsol simulation and experimental tests, demonstrated the feasibility of significantly increasing the temperature of a magnetic composite through a simple induction heating effect. To better highlight such an effect, a comparison with conductive but non-ferromagnetic samples was performed. As opposed to the ferromagnetic composite, its conductive counterpart exhibited a very weak response to the magnetic field excitation, and no temperature effect was achieved. This observation can be explained by “microscopic” eddy currents (i.e., the fact that domain wall motions are predominant mechanisms under low frequency), leading to local temperature variations inside the ferromagnetic particles. These preliminary results seem to be promising, and this effect could be exploited in a medical application, especially for treatment of superficial venous insufficiency, where local heating remains a true challenge. As normal tissues and muscles are conductive, it is necessary to bring the heat “where it is needed”. We believe that LFIH would be able to destroy varicose veins without damaging the neighboring tissues.

Hydrothermal synthesis of magnetic iron oxide encrusted hydrocalumite-chitosan composite for defluoridation studies.

A magnetic adsorbent namely magnetic iron oxide encrusted hydrocalumite-chitosan (Fe3O4@HCCS) composite was prepared by the fabrication of magnetic iron oxide (Fe3O4) particles on hydrocalumite-chitosan (HCCS) composite for fluoride sorption studies in batch mode. The prepared magnetic Fe3O4@HCCS composite possesses an enhanced defluoridation capacity (DC) of 6.8mg/g compared to hydrocalumite (HC) which possesses the DC of 2.4mg/g. The various physico-chemical parameters such as contact time, pH, co-existing anions, initial fluoride concentration and temperature were optimized for the maximum fluoride removal. The structural changes of the sorbent, before and after fluoride sorption were studied using FTIR and SEM with EDAX techniques. The equilibrium data was well modeled by Freundlich and Langmuir isotherms. The thermodynamic parameters revealed the feasibility, spontaneity and endothermic nature of fluoride sorption. The field performance and efficiency of Fe3O4@HCCS composite was examined with the waste-water sample collected from a fluoride endemic area of Dindigul district, Tamilnadu, India using standard protocols.

Tribological Behavior of Glycerol/Water-Based Magnetorheological Fluids in PMMA Point Contacts

The understanding of the tribological behavior of magnetorheological fluids is crucial for many applications, in particular for those related with high quality surface finishing. In this contribution, we describe a thorough experimental investigation on the tribological properties of magnetorheological (MR) fluids in poly(methyl methacrylate) (PMMA) point contacts. First, magnetic iron oxide particles with diameters of approximately 0.4, 1,3 and 2.0 µm were prepared using wet chemistry procedures. Then, MR fluids were formulated by dispersion of the magnetic particles in glycerol/water mixtures. The tribological experiments were run in a PMMA ball-on-three plates tribometer and Stribeck regions were identified for a wide range of sliding speeds. The wear tracks were also visualized in a confocal microscope to correlate them with friction coefficient data. The results show the effect of both particle size and applied magnetic field in the friction coefficient and wear scar volume, suggesting a slight decrease on the wear process when the magnetic field is present.