Presence Of Fe3O4 Nanoparticles Research Articles

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

ABSTRACTThe 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.

Preconcentration of cobalt(II) using polythionine-coated Fe3O4 nanocomposite prior its determination by AAS

The article describes a magnetic nanocomposite (mag-NC) that was obtained by oxidative polymerization of thionine in the presence of Fe3O4 nanoparticles. The mag-NC was characterized by FTIR spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry. It is shown that the mag-NC represents a useful sorbent for magnetic solid-phase extraction of cobalt(II) at trace levels from water and foodstuff samples prior to its determination by FAAS. The effect of pH value, sorbent dose, shaking time and interfering ions on extraction efficiency were optimized. Figures of merits include (a) preconcentration factor of 50, (b) good linearity in the concentration range from 1.3 to 140.0 ng mL−1, (c) a 0.3 ng mL−1 detection limit; and (d) the intra- and inter-day relative standard deviations (for n = 6) of 1.9 and 2.8 %, respectively. Appropriate recovery values, ranging from 96.0 to 104.9 %, were also obtained for real samples analyses.

Removal of Chromium(VI) from Aqueous Solutions Using Fe₃O₄ Magnetic Polymer Microspheres Functionalized with Amino Groups.

Magnetic polymer microspheres (MPMs) using glycidylmethacrylate (GMA) as a functional monomer were synthesized in the presence of Fe3O4 nanoparticles via dispersion polymerization. After polymerization, the magnetic polymer microbeads were modified with ethylenediamine (EDA). The obtained ethylenediamine-functionalized magnetic microspheres (EDA-MPMs) were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM) and Fourier transform infrared (FT-IR) spectroscopy. Then the EDA-MPMs were applied as adsorbents for the removal of Cr(VI) from aqueous solution. Langmuir equation was appropriate to describe the experimental data. The maximum adsorption capacities obtained from the Langmuir model were 236.9, 242.1 and 253.2 mg/g at 298, 308 and 318 K, respectively. The Cr(VI) adsorption equilibrium was established within 120 min and the adsorption kinetics was compatibly described by the pseudo-second order equation. The thermodynamic parameters (ΔG°, ΔH°, ΔS°) of the sorption process revealed that the adsorption was spontaneous and was an endothermic process. The regeneration study demonstrated that the EDA-MPMs could be repeatedly utilized with no significant loss of adsorption efficiency.

A facile strategy for the preparation of a porous flower-like Fe3O4/Cu2O/Ag nanocomposite with unexpected and recyclable photocatalytic activity under visible light irradiation

In this work, a novel magnetic and ordered Fe3O4/Cu2O/Ag ternary composite was successfully synthesized via one-pot method in the presence of Fe3O4 nanoparticles. The glycol-ethanol mixed system was used as both solvent and reductant for the simultaneous formation of Cu2O and Ag. The porous and hollow flower-like Fe3O4/Cu2O/Ag composite was self-assembled by many nanosheets with an average thickness of 10nm and exhibited unexpected photocatalytic activity for the degradation of methyl orange (MO) under visible light. The degradation rate of MO in aqueous solution (1×10−4molL−1) reached to 97.7% within 40min. The (111) facet of Cu2O exhibited higher activity for the absorption of MO. Furthermore, ternary composite could be easily recycled by applying an external magnetic field without significant decrease of the catalytic activity even after running 5 times, which presented higher stability and efficiency than Fe3O4@Cu2O. This work would provide a new sight for the construction of visible light-responsive photocatalysts with high performance.

Microwave Synthesis of Fe2O3 Nanoparticles and Its Catalyst Investigation in One-pot Synthesis of Naphthoxazinone Derivatives

In this work firstly Fe2O3 nanoparticles were synthesized via a simple chemical method. Properties of the product were examined by X-ray diffraction pattern (XRD), Scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectroscopy. Vibrating sample magnetometer (VSM) shows nanoparticles exhibit ferromagnetic behavior. To continue some of the 2-naphthol condensed 1,3-oxazinone derivatives employing one-pot condensation reaction in the presence of Fe2O3 nanoparticles as an acid catalyst were described. The present methodology offers several advantages, viz. high yields, clean reaction, short reaction times, recyclability of the catalyst and simple workup procedure.

Stability and enzyme activity of lysozyme in the presence of Fe3O4 nanoparticles

The goal of this work was investigation the effect of adsorption the Fe3O4 as magnetic nanoparticle on lysozyme activity and thermal stability. The turbidimetric assay (activity) of lysozyme was followed by the decreased optical density of a turbid cell suspension (about 0.3 mg/cm3 Micrococcus lysodeikticus) photometrically at 450 nm. In this study, the effect of nano-Fe3O4 on lysozyme activity was investigated by UV–Vis spectrophotometry at pH = 7.25 at 35 °C using sodium phosphate buffer. Measurements were carried out using 6 × 10−8 M (0.1 mg/cm3) concentration of lysozyme and a range of nano-Fe3O4 concentrations between 0 and 0.06 mg/cm3. It was found that by increasing nano-Fe3O4, the rate of M. lysodeikticus lyses (lysozyme activity) increases. The thermal stability of lysozyme was investigated in the presence of nano-Fe3O4 over the temperature range of 293–363 K in sodium phosphate buffer and pH = 7.25. Results indicated that by increasing nano-Fe3O4, the thermal stability of lysozyme increases.

Synthesis of 1D Fe3O4/P(MBAAm-co-MAA) nanochains as stabilizers for Ag nanoparticles and templates for hollow mesoporous structure, and their applications in catalytic reaction and drug delivery

One-dimensional (1D) magnetic Fe3O4/P(MBAAm-co-MAA) nanochains were prepared by distillation–precipitation polymerization of MBAAm and MAA in the presence of Fe3O4 nanoparticles as building blocks under a magnetic heating stirrer, which played two critical roles: serving as magnetic field to induce the self-assembly of Fe3O4 nanoparticles into 1D nanochains and providing thermal energy to induce the polymerization of MAA and MBAAm on the surface of the Fe3O4 nanoparticles. The thickness of the P(MBAAm-co-MAA) layer can be easily tuned by adjusting the successive polymerization steps. The polymer layer that contained carboxyl groups was used as stabilizers for loading Ag nanoparticles and the reaction locus for deposition of outer silica layer via a sol–gel method in presence of C18TMS as the pore directing agent for tri-layer nanochains. The corresponding hollow mesoporous silica nanochains with movable maghemite cores (γ-Fe2O3@mSiO2) were produced after removal of the polymer mid-layer and the alkyl groups of the pore directing agent via calcination of the tri-layer nanochains at high temperature. The Fe3O4/P(MBAAm-co-MAA)/Ag nanochains exhibited a highly catalytic efficiency and well reusable property toward the reduction of nitrophenol. Furthermore, the γ-Fe2O3@mSiO2 nanochains possessed hollow mesoporous structure and high specific surface area (197.2m2g−1) were used as a drug carrier, which displayed a controlled release property.

Improved production of reducing sugars from rice straw using crude cellulase activated with Fe3O4/Alginate nanocomposite

Effect of Fe3O4 nanoparticles (NPs) and Fe3O4/Alginate nanocomposites (NCs) have been investigated on production and thermostability of crude cellulase enzyme system obtained by newly isolated thermotolerant Aspergillus fumigatus AA001. Fe3O4 NPs and Fe3O4/Alginate NCs have been synthesized by co-precipitation method and characterized through various techniques. In presence of Fe3O4 NPs and Fe3O4/Alginate NCs, filter paper activity of crude cellulase was increased about 35% and 40%, respectively in 72h as compared to control. Fe3O4/Alginate NCs treated crude enzyme was thermally stable up to 8h at 70°C and retained 56% of its relative activity whereas; control samples could retain only 19%. Further, the hydrolysis of 1.0% alkali treated rice straw using Fe3O4/Alginate NCs treated cellulase gave much higher sugar productivity than control at optimal condition. These findings may be utilized in the area of biofuels and biowaste management.

Magnetic thermoresponsive ionic nanogels as novel draw agents in forward osmosis

Magnetic thermosensitive ionic nanogels were prepared based on strong ionic monomer AMPS and thermosensitive monomer NIPAM via precipitation polymerization in the presence of Fe3O4 nanoparticles and investigated as draw solutes in FO.

Fe2O3/TUD-1: an efficient catalysts for Friedel–Crafts alkylation of aromatics

Three-dimensional mesoporous (Fe-TUD-1) catalysts with different Si/Fe ratios (100, 50, 20 and 10) are prepared using triethanolamine as template. Physicochemical and textural measurements by XRD, elemental analysis, N2 adsorption, UV–Vis spectroscopy and HR-TEM imaging indicate the formation of pure solid mesoporous materials and the presence of Fe2O3 nanoparticles in the prepared Fe-TUD-1 samples. The catalytic performance of Fe-TUD-1 catalysts is tested in Friedel–Crafts alkylations of single-ring aromatic compounds [e.g. toluene (T), ethyl benzene (EB) and cumene (C)] by benzyl alcohol (BnOH). Dispersion of Fe(III) in the mesoporous matrix of TUD-1 enhanced the catalytic activity of Fe-TUD-1 in the alkylation of aromatic compounds compared to pure Fe2O3 and TUD-1 catalysts. The catalytic activity further increases by the decreasing of Si/Fe ratio. Sample loaded with Si/Fe ratio = 10 (Fe-10) showed almost complete conversion of BnOH in a relatively very short reaction time (<30 min) with 95 % selectivity. The catalytic performance of Fe-TUD-1 was superior to other metal-containing TUD-1 (e.g. Ga, Sn, and Ti) catalysts, or other Fe-containing catalysts (e.g. Fe-MCM-41, ZSM-5 and Fe-HMS). Alkylation of C is the fastest among the three aromatic substrates investigated (at temperatures very close to their boiling points) due to the largest inductive effect by the isopropyl group compared to the methyl group of T and the ethyl group in EB. Dibenzyl ether is formed as a byproduct only in the early times of the reaction and proved to act as alkylating agent after being hydrolyzed backwards to reform BnOH. Leaching experiments show the Fe-TUD-1 materials are very stable and can be reused as alkylation catalyst.

Simultaneous electrochemical detection of dopamine and ascorbic acid using an iron oxide/reduced graphene oxide modified glassy carbon electrode.

The fabrication of an electrochemical sensor based on an iron oxide/graphene modified glassy carbon electrode (Fe3O4/rGO/GCE) and its simultaneous detection of dopamine (DA) and ascorbic acid (AA) is described here. The Fe3O4/rGO nanocomposite was synthesized via a simple, one step in-situ wet chemical method and characterized by different techniques. The presence of Fe3O4 nanoparticles on the surface of rGO sheets was confirmed by FESEM and TEM images. The electrochemical behavior of Fe3O4/rGO/GCE towards electrocatalytic oxidation of DA was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) analysis. The electrochemical studies revealed that the Fe3O4/rGO/GCE dramatically increased the current response against the DA, due to the synergistic effect emerged between Fe3O4 and rGO. This implies that Fe3O4/rGO/GCE could exhibit excellent electrocatalytic activity and remarkable electron transfer kinetics towards the oxidation of DA. Moreover, the modified sensor electrode portrayed sensitivity and selectivity for simultaneous determination of AA and DA. The observed DPVs response linearly depends on AA and DA concentration in the range of 1–9 mM and 0.5–100 μM, with correlation coefficients of 0.995 and 0.996, respectively. The detection limit of (S/N = 3) was found to be 0.42 and 0.12 μM for AA and DA, respectively.

Synthesis and thermal stability of polystyrene and poly(vinyl chloride) coated with polythiophene and modified with Fe2O3nanoparticles

In this study, polystyrene and poly(vinyl chloride) particles were coated successfully with polythiophene in aqueous media. These nanocomposites were prepared in situ by polymerization of thiophene in the presence of FeCl3 as an oxidant and poly(vinyl pyrrolidone) as a surfactant. The effect of Fe2O3 nanoparticles on the characteristics of products such as thermal stability and morphology was investigated. The chemical structure, morphology, and thermal stability of these core-shell nanocomposites were studied by Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. Thermal stability of the nanocomposites was compared and indicated that the thermal stability of polythiophene/polystyrene was better than the polythiophene/poly(vinyl chloride) nanocomposite. Also, the presence of Fe2O3 nanoparticles can drastically increase the thermal stability of polythiophene nanocomposites. J. VINYL ADDIT. TECHNOL. 20:212–217, 2014. © 2014 Society of Plastics Engineers

ChemInform Abstract: Efficient One‐Pot Synthesis of β‐Acetamido Carbonyl Compounds Using Fe3O4 Nanoparticles.

A new, one-pot condensation of aldehydes, enolizable ketones and esters, AcCl, and MeCN, in the presence of Fe3O4 nanoparticles (nano-Fe3O4) as an efficient catalyst, for the preparation of β-acetamido carbonyl compounds at room temperature is described.

Dendrimer-linked, renewable and magnetic carbon nanotube aerogels

Magnetic carbon nanotube aerogels with a repeated aerogel–sol–hydrogel–aerogel transition have been acquired by the special drying of gel-precursors made via assembling individual nanotubes with dendritic poly(amido amine) molecules in the presence of Fe3O4 nanoparticles, which has inspired us to synthesize renewable 3D porosints composed of organic, inorganic and their hybrid building blocks.

One-pot synthesis of novel Fe3O4/Cu2O/PANI nanocomposites as absorbents in water treatment

Fe3O4/Cu2O/PANI nanocomposites with diverse functionality were prepared for the first time by a one-step in situ polymerization using cupric nitrate as the oxidant for aniline in the presence of Fe3O4 nanoparticles. The morphologies and properties of the Fe3O4/Cu2O/PANI nanocomposites can be controlled by the molar ratio of aniline to Cu2+ ions. Remarkably, a porous dandelion-like nanocomposite with a lower PANI content has been developed as a fast and highly effective sorbent to selectively remove anion organic dyes, such as congo red (CR) and methyl orange (MO), from a simulated sewage system. The flower-like Fe3O4/Cu2O/PANI nanocomposites with higher PANI content could clean up the oil from the water surface easily on account of the superhydrophobicity and excellent lipophilicity. Moreover, the composites could be easily reused using an external magnetic field, because of the presence of Fe3O4. The obtained nanocomposites may have potential applications in water treatment and environmental cleaning.

Investigation of the Role of Reductant on the Size Control of Fe3O4 Nanoparticles on Rice Straw

The goal of this study was to prepare nanocomposites of rice straw coated with different percentages of Fe3O4 nanoparticles (Fe3O4-NPs) [1.0, 5.0, 10.0, and 20.0 wt. %]. In this process, the size of Fe3O4-NPs changed with varying volumes of NaOH (2M). The Fe3O4-NPs were precipitated with sodium hydroxide from a solution of Fe(II) and (III) chloride in water under ambient conditions and N2 gas by the quick precipitation method using urea as a stabilizer. The rice straw/Fe3O4 nanocomposites (NCs) prepared by this method had magnetic properties in percentages higher than ten (10 wt. %). When the volume of NaOH increased, Fe3O4-NPs with uniform size and better distribution could be prepared, which means that the size of the NPs decreased as the reducing agent was increased. Transmission electron microscopy (TEM) showed that Fe3O4-NPs in rice straw were spherical with diameters from 18.47 to 9.93 nm. The SEM results show that the structure of rice straw underwent no particular change. EDX indicated the presence of Fe3O4-NPs on the surface of rice straw. X-ray powder diffraction (PXRD) indicated that the magnetic Fe3O4-NPs were pure and that the particles were small. The FT-IR results showed that the Fe3O4-NPs were successfully coated on the surface of rice straw.

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.

Fabrication, characterization, and properties of poly(ethylene‐co‐vinyl acetate)/magnetite nanocomposites

ABSTRACTPoly(ethylene‐co‐vinyl acetate) (EVA)/magnetite (Fe3O4) nanocomposite was prepared with different loading of Fe3O4 nanoparticles. The mixing and compounding were carried out on a two‐roll mixing mill and the sheets were prepared in a compression‐molding machine. The effect of loading of nanoparticles in EVA was investigated thoroughly by different characterization technique such as transmission electron microscopy (TEM), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), limiting oxygen index (LOI), and technological properties. TEM analysis showed the uniform dispersion of filler in the polymer matrix and the dispersion of filler decreased with increase in filler content. XRD of the nanocomposite revealed the more ordered structure of the polymer chain. An appreciable increase in glass transition temperature was observed owing to the restricted mobility of Fe3O4‐filled EVA nanocomposite. TGA and flame resistance studies indicated that the composites attain better thermal and flame resistance than EVA owing to the interaction of filler and polymer segments. Mechanical properties such as tensile strength, tear resistance, and modulus were increased for composites up to 7 phr of filler, which is presumably owing to aggregation of Fe3O4 nanoparticle at higher loading. The presence of Fe3O4 nanoparticles in the polymer matrix reduced the elongation at break and impact strength while improved hardness of the composite than unfilled EVA. The change in technological properties had been correlated with the variation of polymer–filler interaction estimated from the swelling behavior. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40116.

Efficient One‐Pot Synthesis of β‐Acetamido Carbonyl Compounds Using Fe3O4 Nanoparticles

AbstractA new, one‐pot condensation of aldehydes, enolizable ketones and esters, AcCl, and MeCN, in the presence of Fe3O4 nanoparticles (nano‐Fe3O4) as an efficient catalyst, for the preparation of β‐acetamido carbonyl compounds at room temperature is described.

Hyperbranched polyurethane/Fe3O4 nanoparticles decorated multiwalled carbon nanotube thermosetting nanocomposites as microwave actuated shape memory materials

Abstract