Preparation and property characterization of PAA/Fe3O4 nanocomposite

PAA/Fe₃O₄ nanocomposites were prepared by mixing nano-Fe₃O₄ and polyacrylic acid (PAA) ethanol solution and then evaporating the solvent. The materials were characterized by transmission electron microscope (TEM), Fourier transform infrared spectroscope (FTIR), thermogravimetry analysis (TGA), dynamic ultra-micro hardness tester (DUMHT) and superconducting quantum interference device (SQUID) magnetometer. Results showed that PAA coordinated with nano-Fe₃O₄ to form a cross-linking structure. The presence of nano-Fe₃O₄ enhanced the thermal stability of the nanocomposite. The elasticity and hardness of the nanocomposite increased, and the indentation depth reduced with the increase of Fe₃O₄ content in the composites. The nanocomposites showed superparamagnetic properties at 300 K. Translated from Acta Scientiarum Naturalium Universitatis Sunyatseni, 2006, 45(5): 47–50 [译自: 中山大学学报 (自然科学版)]     

Influence of Fe3O4 nanoparticles decoration on dye adsorption and magnetic separation properties of Fe3O4/rGO nanocomposites

Magnetite (Fe₃O₄) nanoparticles were prepared by solvothermal method and its composites with reduced graphene oxide namely FG1, FG2, and FG3 (changing magnetite precursor loading 0.1, 0.5, and 1 respectively) were used as adsorbents for the removal of methyl violet (MV) dye. The structural and morphological results confirm that rGO sheets were decorated with Fe₃O₄ and it ensures the variation of active sites toward dye removal property. The maximum adsorption capacity obtained for FG2 was 196 mg/g. The adsorption isotherms and kinetics better fit Langmuir and pseudo-second-order kinetic model for FG1 and FG2. Increasing of Fe₃O₄ loading on rGO reduces the dye adsorption sites and too low Fe₃O₄ loading affects the magnetic separation. The optimal loading of Fe₃O₄ on rGO is important parameter for the adsorption process and fast separation of adsorbent.     

Novel conductive magnetic nanocomposite based on poly (indole-co-thiophene) as a hemoglobin diagnostic biosensor: Synthesis,characterization and physical properties

The novel conductive nanocomposite has been successfully prepared by emulsion polymerization. First, magnetite nanoparticles were synthesized via coprecipitation reaction. Then, poly (indole-co-thiophene)@Fe₃O₄ nanocomposite was prepared via emulsion copolymerization of indole and thiophene monomers using sodium dodecyl sulfate as an emulsifier and ammonium persulfate as an oxidant in the presence of Fe₃O₄ nanoparticles. Characterization of the synthesized copolymer, Poly (In-co-T), and its magnetic nanocomposite were studied by Fourier transform infrared spectra, X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, differential scanning calorimetric, UV-vis spectrophotometer, and vibrating sample magnetometer. Also, the electrical conductivity of copolymer and nanocomposite were determined by four-probe instrument. Results showed a synergic effect in thermal stability by good interaction between polymer chain and magnetic nanoparticles. The conductivity of the nanocomposite was higher than bare copolymer, and increase of nanoparticles content caused an increment in the conductivity of the nanocomposites. The applicable properties of proposed conductive nanocomposite as a base at electrochemical biosensing have been investigated.     

Electro-Magnetic Polyfuran/Fe3O4 Nanocomposite: Synthesis,Characterization, Antioxidant Activity,and Its Application as a Biosensor

Herein, the authors report the synthesis of electro-magnetic polyfuran/Fe₃O₄ nanocomposites using Fe₃O₄ magnetic nanoparticles of different content as nucleation sites via in situ chemical oxidation polymerization method. Surface, structural, morphological, thermal, electrical and magnetic properties of the nanocomposites were studied by FT-IR, UV-visible spectroscopies, XRD, FESEM, TGA, four probe, and VSM, respectively. The effect of Fe₃O₄ nanoparticles content on the electrical conductivity and magnetization of nanocomposites was studied. The obtained polyfuran and polyfuran/Fe₃O₄ nanocomposites were analyzed for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. In addition, polyfuran/Fe₃O₄ nanocomposites have been investigated for application as electrochemical biosensor.     

A Novel Strategy for Synthesis of Polystyrene/Fe3O4 Nanocomposite: RAFT Polymerization,Functionalization, and Coordination Techniques

A facile strategy for the synthesis of polystyrene/Fe₃O₄ nanocomposite is suggested. For this purpose, styrene and 4-chloromethyl styrene monomers was copolymerized through reversible addition of fragmentation chain transfer technique [P(St-co-CMSt)] and then the chlorine groups of CMSt units were converted to diethyl malonate groups through a nucleophilic substitution reaction. Afterward, esteric groups of diethyl malonate were hydrolyzed to afford carboxylic acid-functionalized polystyrene. This polymer with carboxylic acid groups can adsorbed onto the surface of Fe₃O₄ nanoparticles through the interaction with hydroxyl groups onto the surface of the nanoparticles. We envision that the synthesized PSt/Fe₃O₄ nanocomposite may be find applications in electromagnetic interference shielding and environment sciences.     

聚乙二醇/聚乙烯吡咯烷酮修饰的纳米Fe3O4粒子的制备与表征

为了获得能够在水中稳定分散,具有广泛应用前景的磁性纳米粒子,以不同分子量的聚乙烯吡咯烷酮(PVP)作为修饰剂,在聚乙二醇(PEG)中高温热分解乙酰丙酮铁(Fe(acac)₃)制备了纳米Fe₃O₄粒子。采用X射线粉末衍射仪(XRD)、透射电镜(TEM)、高分辨透射电镜(HRTEM)、超导量子干涉仪(SQUID)、热重分析仪(TGA)、傅里叶变换红外光谱仪(FT-IR)、纳米粒度与zeta电位分析仪对样品进行了表征,并对样品在生理盐水和生理缓冲液中的稳定性进行了研究,结果表明:制备的纳米Fe₃O₄粒子具有高的结晶度以及单分散性,在300 K下,具有超顺磁性和较高的饱和磁化强度;PEG和PVP共同修饰于纳米Fe₃O₄粒子表面,为纳米Fe₃O₄粒子提供了良好的水分散性;制备的纳米Fe₃O₄粒子在生理盐水和多种生理缓冲液中能够高度溶解并稳定地分散。水中的纳米Fe₃O₄粒子表面呈电中性,表面修饰层的空间位阻效应是所制备的纳米粒子在水溶液中高分散的原因。     

A novel method for the synthesis of Fe3O4 nanoparticles/CdS nanowires heterostructure nanocomposite and uses in photodegradation of methylene blue

We report here a simple, efficient, practical, and novel method for the preparation of Fe₃O₄ nanoparticles (NPs)/CdS nanowires. The CdS nanowire/Fe₃O₄ NP reported here was characterized by transmission electron microscopy (TEM), X-ray Diffraction (XRD), vibrating sample magnetometer (VSM), and energy-dispersive X-ray. Cadmium diethyl dithiophosphate has been used as a 3 in 1 precursor (cadmium, sulfur, and ligand source) for the synthesis of high-quality one-dimensional Fe₃O₄ NPs/CdS nanowires using a simple hydrothermal method in the presence of Fe₃O₄ NPs in water. Photocatalytic activity studies show that the nanocomposite has good photocatalytic activity toward the photodegradation of methylene blue in an aqueous solution.     

Facile Synthesis of FeCo/Fe3O4 Nanocomposite with High Wave-Absorbing Properties

The FeCo/Fe₃O₄ nanocomposite was synthesized using the hydrothermal approach, in which the FeCo alloy and Fe₃O₄ are formed by one step. The structure of the FeCo/Fe₃O₄ nanocomposite was characterized by means of Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray energy-dispersive spectrometer spectroscopy (EDX). They show that the mass ratio of FeCo/Fe₃O₄ strongly depends on the reaction temperature. Such various architectures follow a stepwise growth mechanism of the composites prepared in various reaction temperatures were also discussed. It indicates that this strategy is facile, effective and controllable for the synthesis of FeCo/Fe₃O₄ by the one-step method. Furthermore, the magnetic and wave-absorbing properties of the nanocomposites with various structures were investigated in detail. The results show that the FeCo/Fe₃O₄ with higher mass ratio has higher magnetic properties. Moreover, the FeCo/Fe₃O₄ nanocomposite shows high wave-absorbing properties (e.g., −37.9 dB), which are expected to apply in microwave absorbing materials.     

Improved interfacial properties of carbon fiber-reinforced epoxy composites with Fe2O3/graphene nanosheets using a magnetic field

The performance of carbon fiber-reinforced composites largely depends on the properties of the fiber-matrix interface. Here, to improve the interfacial strength properties of carbon fiber/epoxy composites, we doped different concentrations of Fe₂O₃/graphene nanosheets onto the interfacial region of the carbon fiber composites by nano-coating technology. With the aid of the magnetic field, the arrangement of nanosheets could be controlled in the interface. The nanosheets can be arranged on the carbon fiber surface parallel or perpendicularly with different concentrations. The tensile strength and interfacial shear strength of the modified fiber microcomposites had increased by 22.1 and 44.4% respectively with 1.0 mg/mL Fe₂O₃/graphene nanosheets. The results indicated that the Fe₂O₃/graphene nanosheets have an important influence on the carbon fibers and carbon fibers composites.     

Influence of Co3O4, Fe2O3 and SiC on microstructure and properties of glass foam from waste cathode ray tube display panel (CRT)

Abstract

In the present study, the effect of temperature and oxidising agents such as Fe₂O₃ and Co₃O₄ on physical and mechanical properties of glass foam is investigated. The glass foam is made of panel glass from dismantled cathode ray tubes and SiC as a foaming agent. In the process, powdered waste glass (mean particle size below 63 μm) in addition to 4 wt-% SiC powder (mean particle size below 45 μm) are combined with Fe₂O₃ and Co₃O₄ (0·4, 0·8 and 1·2 wt-%) have been sintered at 950 and 1050°C. The glass foamed containing 1·2 wt-% Co₃O₄ has good physical properties, with porosity more than 80% and bending strength more than 1·57±0·12 MPa. However, by adding different amounts of Fe₂O₃ in comparison with samples without iron oxide, little changes in porosity and strength are obtained.     

Hydrothermal synthesis of 3D hollow porous Fe3O4 microspheres towards catalytic removal of organic pollutants

Three-dimensional hollow porous superparamagnetic Fe₃O₄ microspheres were synthesized via a facile hydrothermal process. A series of characterizations done with X-ray diffraction, Brunauer-Emmett-Teller method, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy indicated that the production of Fe₃O₄ microspheres possessed good monodispersity, uniform size distribution, hollow and porous structural characters, and strong superparamagnetic behavior. The obtained Fe₃O₄ microspheres have a diameter of ca. 300 nm, which is composed of many interconnected nanoparticles with a size of ca. 20 nm. The saturation magnetization is 80.6 emu·g^-1. The as-prepared products had promising applications as novel catalysts to remove organic pollutants (methylene blue) from wastewater in the presence of H₂O₂ and ultrasound irradiation.     

An efficient method for synthesis of some heterocyclic compounds containing 3-iminoisatin and 1,2,4-triazole using Fe3O4 magnetic nanoparticles

1,2,4-triazole derivatives were prepared by reaction of thiocarbohydrazide and some esters in 60% ethanol. Condensation of 1,2,4-triazole derivatives with isatin gave Schiff bases of 3-iminoisatin derivatives. Reaction of malonic or succinic acid dihydrazide with isatin lead to formation of N,N'-bis-(3-imino-1,3-dihydro-indolyl-2-one)-malonamide 8a and N,N'-bis-(3-imino-1,3-dihydro-indolyl-2-one)succinamide 8b in good yields under mild reaction conditions. These reactions are catalyzed by Fe₃O₄ MNPs. The chemical structures were confirmed by Fourier transform-infrared, ¹H-NMR, ¹³C-NMR, gas chromatography-mass spectrometry spectroscopy, and elemental analysis.     

Synthesis of Magnetic Fe3O4 Modified Graphene Nanocomposite and its Application on the Adsorption of some Dyes from Aqueous Solution

A novel magnetic Fe₃O₄ modified reduced graphene oxide nanocomposite (Fe₃O₄@SiO₂-rGO) was prepared by a covalent bonding method. The morphology and properties of the Fe₃O₄@SiO₂-rGO were characterized by transmission electron microscopy and X-ray diffraction. The prepared Fe₃O₄@SiO₂-rGO was tested as an efficient adsorbent for the removal of some dyes from aqueous solution for the first time. The performance of Fe₃O₄@SiO₂-rGO was evaluated using methylene blue and neutral red as model compounds. Experiments were carried out to investigate the adsorption kinetics and adsorption capacity of the adsorbent and the effect of the adsorbent dosage and sample solution pH on the removal of the dyes. Kinetic data were well fitted by pseudo second-order model. The Langmuir model and the Freundlich model were used to study the adsorption isotherms. The Fe₃O₄@SiO₂-rGO nanocomposite showed to be a highly efficient adsorbent with the advantage of separation convenience. The thermodynamic parameters indicated that the adsorption of the dyes onto the Fe₃O₄@SiO₂-rGO was a spontaneous process.     

Magnetic and optical properties of poly(vinylidene difluoride)/Fe3O4 nanocomposite prepared by coprecipitation approach

Poly(vinylidene difluoride) (PVDF)/Fe₃O₄ magnetic nanocomposite was prepared by a simple coprecipitation method, and was characterized by scanning electron microscope (SEM), X‐ray diffraction (XRD), vibrating sample magnetometer (VSM), and ultraviolet visible spectroscopy (UV‐Vis). The SEM images showed that Fe₃O₄ nanoparticles were dispersed in the PVDF matrix as some aggregates with the sizes of 50 nm–2 μm, and the XRD curves showed the incorporation of the Fe₃O₄ nanoparticles in PVDF matrices and the decrease of the crystallinity of the PVDF. VSM results showed that the saturation magnetization (M_s) and remnant magnetization (M_r) of the PVDF/Fe₃O₄ nanocomposite increased with the increase of the Fe₃O₄ content, and that M_s and M_r along the parallel direction were higher than those along the perpendicular direction at the same Fe₃O₄ content. The coercive force (H_c) of the nanocomposite was independent of the Fe₃O₄ content and approximately equal along the parallel and perpendicular direction at the same Fe₃O₄ content. The optical band gap (E_g) of the PVDF/Fe₃O₄ nanocomposite was influenced by the Fe₃O₄ content, and decreased by 0.75 eV compared with that of pure PVDF when the Fe₃O₄ content was 3 wt %. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Enhanced removal of lead and cadmium from water by Fe3O4-cross linked-O-phenylenediamine nano-composite

A method is presented for surface encapsulation of nano-Fe₃O₄ by o-phenylenediamine via cross-linking using formaldehyde and glutaraldhyde for the formation of two newly designed magnetic nano-sorbents. These have been characterized by FT-IR, TGA, and SEM and maintained the magnetic and thermal stability characters. The metal capacity values of Pb(II) and Cd(II) have been optimized in presence of different physico-chemical parameters and confirmed the superior selectivity for Pb(II). Maximum capacity values of Pb(II) (7000-10000 ± 250-675 µmol g^?1) and Cd(II) (1500-2250 ± 30-75 µmol g^?1) at optimum conditions and excellent extraction values (94.10-100.0 ± 1.2-3.5%) from industrial wastewater have been identified.     

Synthesis of MIL-Modified Fe3O4 Magnetic Nanoparticles for Enhancing Uptake and Efficiency of Temozolomide in Glioblastoma Treatment

A nanometric hybrid system consisting of a Fe₃O₄ magnetic nanoparticles modified through the growth of Fe-based Metal-organic frameworks of the MIL (Materials Institute Lavoiser) was developed. The obtained system retains both the nanometer dimensions and the magnetic properties of the Fe₃O₄ nanoparticles and possesses increased the loading capability due to the highly porous Fe-MIL. It was tested to load, carry and release temozolomide (TMZ) for the treatment of glioblastoma multiforme one of the most aggressive and deadly human cancers. The chemical characterization of the hybrid system was performed through various complementary techniques: X-ray-diffraction, thermogravimetric analysis, FT-IR and X-ray photoelectron spectroscopies. The nanomaterial showed low toxicity and an increased adsorption capacity compared to bare Fe₃O₄ magnetic nanoparticles (MNPs). It can load about 12 mg/g of TMZ and carry the drug into A172 cells without degradation. Our experimental data confirm that, after 48 h of treatment, the TMZ-loaded hybrid nanoparticles (15 and 20 μg/mL) suppressed human glioblastoma cell viability much more effectively than the free drug. Finally, we found that the internalization of the MIL-modified system is more evident than bare MNPs at all the used concentrations both in the cytoplasm and in the nucleus suggesting that it can be capable of overcoming the blood-brain barrier and targeting brain tumors. In conclusion, these results indicate that this combined nanoparticle represents a highly promising drug delivery system for TMZ targeting into cancer cells.     

磁性Fe3O4纳米粒子用作靶向药物载体的制备及分析

Fe3O4 magnetic nanoparticles were prepared by the aqueous co-precipitation of FeCl3-6H2O and FeCl2-4H2O with addition of ammonium hydroxide. The conditions for the preparation of Fe3O4 magnetic nanoparticles were optimized, and Fe3O4 magnetic nanoparticles obtained were characterized systematically by means of transmission electron microscope （TEM）, dynamic laser scattering analyzer （DLS） and X-ray diffraction （XRD）. The results revealed that the magnetic nanoparticles were cubic shaped and dispersive, with narrow size distribution and average diameter of 11.4 nm. It was found that the homogeneous variation of pH value in the solution via the control on the dropping rate of aqueous ammonia played a critical role in size distribution. The magnetic response of the product in the magnetic field was also analyzed and evaluated carefully. A 32.6 mT magnetic field which is produced by four ferromagnets was found to be sufficient to excite the dipole moments of 0.05 g Fe3O4 powder 2 cm far away from the ferromagnets. In conclusion, the Fe3O4 magnetic nanoparticles with excellent properties were competent for the magnetic carders of targeted-drug in future application.     

Fe3O4@SiO2-SnCl4: An Efficient Catalyst for the Synthesis of Xanthene Derivatives under Ultrasonic Irradiation

Grafting of SnCl₄ on the Fe₃O₄@SiO₂ nanoparticles afforded Fe₃O₄@SiO₂-SnCl₄ as a novel inorganic heterogenous catalyst, which was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), Field Emission Scanning Electron Microscopy (FE-SEM), and transmission electron microscopy (TEM). In this research, we report a convenient and efficient direct protocol for the preparation of xanthene derivatives via condensation of β-naphthol, dimedone, or mixture of β-naphthol and dimedone with various aromatic aldehydes in the presence of the catalytic amount of Fe₃O₄@SiO₂-SnCl₄ under ultrasonic irradiation. This procedure has a lot of advantages such as: very easy reaction conditions, absence of any tedious workup, or purification, and much milder method. The corresponding products have been obtained in excellent yields, high purity, and short reaction times.     

The Magnetism Properties and Surface Microstructure of NBR/Fe3O4 Composites

For preparing the good magnetism properties of rubber, NBR/Fe₃O₄ composites are prepared. In the experiment, the surface microstructure of NBR/Fe₃O₄ and distribution of nano-Fe₃O₄ particles are analyzed. The results showed that after the addition of nano-Fe₃O₄, the surface microstructure of NBR/Fe₃O₄ is greatly improved. The interface bonding of nano-Fe₃O₄ and NBR are close-knit. With adding different mass fractions of nanoparticles, the maximum elongation 300% stress at definite elongation and the tensile strength of composites are decreased, but the shore A hardness of composites is improved. The magnetic property of composites can only rely on mass fraction of nano-Fe₃O₄, while uncorrelated to the degree of scatter of nano-Fe₃O₄.     

Chitosan–Fe3O4 nanocomposite based electrochemical sensors for the determination of bisphenol A

This paper reports the application of chitosan–Fe₃O₄ (CS–Fe₃O₄) nanocomposite modified glassy carbon electrodes for the amperometric determination of bisphenol A (BPA). We observed that the CS–Fe₃O₄ nanocomposite could remarkably enhance the current response and decrease its oxidation overpotential in the electrochemical detection. Experimental parameters, such as the amount of the CS–Fe₃O₄, the accumulation potential and time, the pH value of buffer solution etc. were optimized. Under the optimized conditions, the oxidation peak current was proportional to BPA concentration in the range between 5.0 × 10⁻⁸ and 3.0 × 10⁻⁵ mol dm⁻³ with the correlation coefficient of 0.9992 and the limit of detection of 8.0 × 10⁻⁹ mol dm⁻³ (S/N = 3). The proposed sensors were successfully employed to determine BPA in real plastic products and the recoveries were between 92.0% and 06.2%. This strategy might open more opportunities for the electrochemical determination of BPA in practical applications. Additionally, the leaching studies of BPA on incubation time using the as-prepared modified electrode were successfully carried out.