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Sample records for fe3o4 polymer composites

  1. Inductive heat property of Fe3O4/polymer composite nanoparticles in an ac magnetic field for localized hyperthermia.

    PubMed

    Zhao, Dong-Lin; Zhang, Hai-Long; Zeng, Xian-Wei; Xia, Qi-Sheng; Tang, Jin-Tian

    2006-12-01

    The magnetite (Fe(3)O(4)) nanoparticles were prepared by coprecipitation of Fe(3+) and Fe(2+) with an aqueous NaOH solution. The Fe(3)O(4)/polyaniline (PANI) magnetic composite nanoparticles with a core-shell structure with a diameter of 30-50 nm were prepared via an in situ polymerization of aniline in an aqueous solution containing the Fe(3)O(4) magnetic fluid. The inductive heat property of Fe(3)O(4)/PANI composite nanoparticles in an alternating current (ac) magnetic field was investigated. The potential of Fe(3)O(4)/PANI nanoparticles was evaluated for localized hyperthermia treatment of cancers. The saturation magnetization, M(s), and coercivity, H(c), are 50.05 emu g(-1) and 137 Oe for Fe(3)O(4) nanoparticles and 26.34 emu g(-1) and 0 Oe for Fe(3)O(4)/PANI composite nanoparticles, respectively. Exposed in the ac magnetic field for 29 min, the temperatures of physiological saline suspensions containing Fe(3)O(4) nanoparticles or Fe(3)O(4)/PANI composite nanoparticles are 63.6 degrees C and 52.4 degrees C, respectively. The Fe(3)O(4)/PANI composite nanoparticles would be useful as good thermoseeds for localized hyperthermia treatment of cancers. PMID:18458406

  2. One step grafting of iron phthalocyanine containing flexible chains on Fe3O4 nanoparticles towards high performance polymer magnetic composites

    NASA Astrophysics Data System (ADS)

    Pu, Zejun; Zhou, Xuefei; Yang, Xulin; Jia, Kun; Liu, Xiaobo

    2015-07-01

    To develop high-performance inorganic particles/polymer composites, the interfacial interaction and dispersion of inorganic particles are the two essential issues to be considered. Herein, we report an effective approach to graft iron phthalocyanine containing flexible chains (NP-ph) on Fe3O4 nanoparticles (NP-ph@Fe3O4). The hybrids were monodispersed solid nanoparticles with the average diameter of about 250 nm. About 16.8% of the phthalocyanine oligomer was incorporated into the resulting NP-ph@Fe3O4 nanoparticles. The NP-ph@Fe3O4 nanoparticles were subsequently used as the novel filler for preparation of high performance poly(arylene ether nitrile)s (PAEN) composites. The scanning electron microscopy (SEM) investigation showed that the NP-ph@Fe3O4 nanoparticles present better dispersion and interfacial compatibility with PAEN matrix than that of raw Fe3O4, which was further confirmed by rheological study. Consequently, the improved thermal stability and enhanced mechanical properties were obtained from composites using NP-ph@Fe3O4. Vibrating sample magnetometer (VSM) results showed that the prepared PAEN composites exhibited higher saturation magnetization and soft magnetic properties. Meanwhile, the saturation magnetization (Ms) of the PAEN/NP-ph@Fe3O4 composite films increased with the increase of the hybrid nanoparticles loading. Thus, the PAEN/NP-ph@Fe3O4 composite would find potential applications in organic magnetic films fields due to their high thermal stability, excellent flexibility and tunable magnetic properties

  3. Fe3O4@polydopamine Composite Theranostic Superparticles Employing Preassembled Fe3O4 Nanoparticles as the Core.

    PubMed

    Ge, Rui; Li, Xing; Lin, Min; Wang, Dandan; Li, Shuyao; Liu, Shuwei; Tang, Qi; Liu, Yi; Jiang, Jinlan; Liu, Lidi; Sun, Hongchen; Zhang, Hao; Yang, Bai

    2016-09-01

    Iron oxide (Fe3O4), polydopamine (PDA), and in particular their composites are examples of the safest nanomaterials for developing multifunctional nanodevices to perform noninvasive tumor diagnosis and therapy. However, the structures and performances of Fe3O4-PDA nanocomposites should be further perfected to enhance the theranostic efficiency. In this work, we demonstrate the fabrication of PDA-capped Fe3O4 (Fe3O4@PDA) superparticles (SPs) employing preassembled Fe3O4 nanoparticles (NPs) as the cores. Owing to the collective effect of preassembled Fe3O4 NPs, the superparamagnetism and photothermal performance of Fe3O4@PDA SPs are greatly enhanced, thus producing nanodevices with improved magnetic resonance imaging (MRI)-guided photothermal efficiency. Systematical studies reveal that the molar extinction coefficient of the as-assembled Fe3O4 SPs is 3 orders of magnitude higher than that of individual Fe3O4 NPs. Also due to the high aggregation degree of Fe3O4 NPs, the T2-weighted MRI contrast is greatly enhanced for the SPs with r2 relaxivity of 230.5 mM(-1) s(-1), which is ∼2.5 times larger than that of individual Fe3O4 NPs. The photothermal stability, physiological stability, and biocompatibility, as well as the photothermal performance of Fe3O4 SPs, are further improved by enveloping with PDA shell. PMID:27560801

  4. Adsorption and desorption studies of lysozyme by Fe3O4-polymer nanocomposite via fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Koc, Kenan; Alveroglu, Esra

    2015-06-01

    The work have been undertaken in this study is to synthesis and characterize Fe3O4-polymer nanocomposites which are having different morphological properties. Also, investigation of the adsorption and desorption behaviour of lysozyme onto Fe3O4-polymer nanocomposites have been studied. Fe3O4 nanoparticles, synthesized by in situ in polyacrylamide hydrogels, show super-paramagnetic behaviour and saturation magnetization of composite material have been tuned by changing the hydrogel conformation. Adsorption and desorption studies of lysozyme were followed by using pure water at room temperature via fluorescence measurements. Fluorescence measurements showed that, the composite materials adsorbed lysozyme molecules less than 20 s and higher monomer concentration of composite materials cause faster adsorption. Besides, structure of lysozyme molecules were not changed during the adsorption and desorption. As a result Fe3O4-polymer nanocomposites could be used for drug delivery, protein separation and PAAm gels could be used for synthesis of magnetic composites with varying magnetic properties.

  5. Magnetoresistance effect in Ag-Fe3O4 and Al-Fe3O4 composite films

    NASA Astrophysics Data System (ADS)

    Hsu, Jen-Hwa; Chen, Shang-Yi; Chang, Wen-Ming; Jian, T. S.; Chang, Ching-Ray; Lee, Shan-Fan

    2003-05-01

    The Agx-(Fe3O4)1-x and Agx-(Fe3O4)1-x composite films were prepared by dc sputtering on Si(100) substrates. The x-ray diffraction results show that the films contain essentially only the cubic inverse spinal phase from Fe3O4 and face-centered cubic phase from Ag or Al. The transmission electron microscopy images indicate that the metal granules are randomly distributed with Fe3O4 grains. The resistivity determined from the four-probe method decreases rapidly with increasing metal content. At x≒0.5, a percolation occurs. The conducting path is formed from metal granules in series with Fe3O4 grains. The magnetoresistance (MR) is defined to be {R(H=0.8 T)-R(H=0)}/R(H=0). It has been found that MR is isotropic and the appearance of Ag granules has significant impact on the MR effect. Furthermore, a positive MR region appears with 0.011Fe3O4)1-x. On the contrary, the incorporation of Al granules does not have the same effect on MR as in Agx-(Fe3O4)1-x. A slow increase of MR with Al content might be due to Coulomb blockade. The extra contribution to MR in Agx-(Fe3O4)1-x can be attributed to spin injection from Fe3O4 into Ag granules so that spin accumulation in Ag granules impedes the current causing a larger resistance under a field.

  6. Ultrasonic-assisted magnetic solid phase extraction of morphine in urine samples by new imprinted polymer-supported on MWCNT-Fe3O4-NPs: Central composite design optimization.

    PubMed

    Kolaei, Milad; Dashtian, Kheibar; Rafiee, Zahra; Ghaedi, Mehrorang

    2016-11-01

    Multiwalled carbon nanotubes (MWCNTs) were magnetized with Fe3O4 nanoparticles (MWCNTs-Fe3O4-NPs) and subsequently coated by vinyl end groups (Vinyltrimethoxysilane). MWCNT-Fe3O4-NPs were used as support for a new morphine (MO) molecularly imprinted polymer (MWCNT-Fe3O4-NPs@MO-MIP) by surface imprinting polymerization method. The MWCNT-Fe3O4-NPs@MO-MIP was characterized by FTIR, VSM and SEM techniques and successfully used for determination of MO. Ultrasonic-assisted magnetic solid phase extraction followed by UV-vis spectrophotometer (UAMSPE-UV-vis) was investigated for MWCNT-Fe3O4-NPs@MO-MIP and compared with non-imprinted polymer (NIP) using batch method. Central composite design under response surface methodology was used for the evaluation of the effect of variables, individually, as well as their possible interaction effects on the adsorption process. The variables such as sonication time, MWCNT-Fe3O4-NPs@MO-MIP mass, initial concentration of MO and pH were investigated in this study. At optimum experimental conditions, UAMSPE-UV-vis method was exhibited a linear range of 0.8-8.7mgL(-1) of the MO concentration with a detection limit of 0.18mgL(-1). The relative standard deviation for the analyte was found to be lower than 2.32%. The MWCNT-Fe3O4-NPs@MO-MIP adsorption capacity was found to be 37.01mgg(-1). The enrichment and preconcentration factors were found to be 107.01 and 98.21, respectively. The developed method was finally applied successfully to the determination of MO in urine and wastewater samples with the recoveries ranged from 96.40 to 105.6%. PMID:27245975

  7. Properties of poly(1-naphthylamine)/Fe3O4 composites and arsenic adsorption capacity in wastewater

    NASA Astrophysics Data System (ADS)

    Tran, Minh Thi; Nguyen, Thi Huyen Trang; Vu, Quoc Trung; Nguyen, Minh Vuong

    2016-03-01

    The research results of poly(1-naphthylamine)/Fe3O4 (PNA/Fe3O4) nanocomposites synthesized by a chemical method for As(III) wastewater treatment are presented in this paper. XRD patterns and TEM images showed that the Fe3O4 grain size varied from 13 to 20 nm. The results of Raman spectral analysis showed that PNA participated in part of the PNA/Fe3O4 composite samples. The grain size of PNA/Fe3O4 composite samples is about 25-30 nm measured by SEM. The results of vibrating sample magnetometer measurements at room temperature showed that the saturation magnetic moment of PNA/Fe3O4 samples decreased from 63.13 to 43.43 emu/g, while the PNA concentration increased from 5% to 15%. The nitrogen adsorption-desorption isotherm of samples at 77 K at a relative pressure P/ P 0 of about 1 was studied in order to investigate the surface and porous structure of nanoparticles by the BET method. Although the saturation magnetic moments of samples decreased with the polymer concentration increase, the arsenic adsorption capacity of the PNA/Fe3O4 sample with the PNA concentration of 5% is better than that of Fe3O4 in a solution with pH = 7. In the solution with pH > 14, the arsenic adsorption of magnetic nanoparticles is insignificant.

  8. Synthesis, characterization and magnetic properties of Fe3O4 doped chitosan polymer

    NASA Astrophysics Data System (ADS)

    Karaca, E.; Şatır, M.; Kazan, S.; Açıkgöz, M.; Öztürk, E.; Gürdağ, G.; Ulutaş, D.

    2015-01-01

    Fe3O4 nanoparticles doped into chitosan films were prepared by the solution casting technique. Various samples were synthesized in atmospheric medium and in vacuum. The morphological properties of the samples were characterized by high resolution transmission electron microscopy (HR-TEM) and Scanning Electron Microscopy (SEM). The structural, magnetic, and microwave absorption properties of magnetic chitosan films have been carried out using the Vibrating Sample Magnetometer (VSM) and Ferromagnetic Resonance (FMR). It is shown that the composite polymer behaves like a superparamagnetic material with high blocking temperature. The effective magnetization shows gradual increments with the concentration of dopant Fe3O4 nanoparticles. The microwave absorption characteristic of superparamagnetic composite polymer shows low reflection loss.

  9. Dispersion of Nanocrystalline Fe3O4 within Composite Electrodes: Insights on Battery-Related Electrochemistry.

    PubMed

    Bock, David C; Pelliccione, Christopher J; Zhang, Wei; Wang, Jiajun; Knehr, K W; Wang, Jun; Wang, Feng; West, Alan C; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

    2016-05-11

    Aggregation of nanosized materials in composite lithium-ion-battery electrodes can be a significant factor influencing electrochemical behavior. In this study, aggregation was controlled in magnetite, Fe3O4, composite electrodes via oleic acid capping and subsequent dispersion in a carbon black matrix. A heat treatment process was effective in the removal of the oleic acid capping agent while preserving a high degree of Fe3O4 dispersion. Electrochemical testing showed that Fe3O4 dispersion is initially beneficial in delivering a higher functional capacity, in agreement with continuum model simulations. However, increased capacity fade upon extended cycling was observed for the dispersed Fe3O4 composites relative to the aggregated Fe3O4 composites. X-ray absorption spectroscopy measurements of electrodes post cycling indicated that the dispersed Fe3O4 electrodes are more oxidized in the discharged state, consistent with reduced reversibility compared with the aggregated sample. Higher charge-transfer resistance for the dispersed sample after cycling suggests increased surface-film formation on the dispersed, high-surface-area nanocrystalline Fe3O4 compared to the aggregated materials. This study provides insight into the specific effects of aggregation on electrochemistry through a multiscale view of mechanisms for magnetite composite electrodes. PMID:27096464

  10. Dispersion of nanocrystalline Fe3O4 within composite electrodes: Insights on battery-related electrochemistry

    DOE PAGESBeta

    David C. Bock; Takeuchi, Kenneth J.; Pelliccione, Christopher J.; Zhang, Wei; Wang, Jiajun; Knehr, K. W.; Wang, Jun; Wang, Feng; West, Alan C.; Marschilok, Amy C.; et al

    2016-04-20

    Aggregation of nanosized materials in composite lithium-ion-battery electrodes can be a significant factor influencing electrochemical behavior. In this study, aggregation was controlled in magnetite, Fe3O4, composite electrodes via oleic acid capping and subsequent dispersion in a carbon black matrix. A heat treatment process was effective in the removal of the oleic acid capping agent while preserving a high degree of Fe3O4 dispersion. Electrochemical testing showed that Fe3O4 dispersion is initially beneficial in delivering a higher functional capacity, in agreement with continuum model simulations. However, increased capacity fade upon extended cycling was observed for the dispersed Fe3O4 composites relative to themore » aggregated Fe3O4 composites. X-ray absorption spectroscopy measurements of electrodes post cycling indicated that the dispersed Fe3O4 electrodes are more oxidized in the discharged state, consistent with reduced reversibility compared with the aggregated sample. Higher charge-transfer resistance for the dispersed sample after cycling suggests increased surface-film formation on the dispersed, high-surface-area nanocrystalline Fe3O4 compared to the aggregated materials. Furthermore, this study provides insight into the specific effects of aggregation on electrochemistry through a multiscale view of mechanisms for magnetite composite electrodes.« less

  11. Hollow superparamagnetic PLGA/Fe 3O 4 composite microspheres for lysozyme adsorption

    NASA Astrophysics Data System (ADS)

    Yang, Qi; Wu, Yao; Lan, Fang; Ma, Shaohua; Xie, Liqin; He, Bin; Gu, Zhongwei

    2014-02-01

    Uniform hollow superparamagnetic poly(lactic-co-glycolic acid) (PLGA)/Fe3O4 composite microspheres composed of an inner cavity, PLGA inner shell and Fe3O4 outer shell have been synthesized by a modified oil-in-water (O/W) emulsion-solvent evaporation method using Fe3O4 nanoparticles as a particulate emulsifier. The obtained composite microspheres with an average diameter of 2.5 μm showed excellent monodispersity and stability in aqueous medium, strong magnetic responsiveness, high magnetite content (>68%), high saturation magnetization (58 emu g-1) and high efficiency in lysozyme adsorption.

  12. Hollow superparamagnetic PLGA/Fe3O4 composite microspheres for lysozyme adsorption.

    PubMed

    Yang, Qi; Wu, Yao; Lan, Fang; Ma, Shaohua; Xie, Liqin; He, Bin; Gu, Zhongwei

    2014-02-28

    Uniform hollow superparamagnetic poly(lactic-co-glycolic acid) (PLGA)/Fe(3)O(4) composite microspheres composed of an inner cavity, PLGA inner shell and Fe(3)O(4) outer shell have been synthesized by a modified oil-in-water (O/W) emulsion-solvent evaporation method using Fe(3)O(4) nanoparticles as a particulate emulsifier. The obtained composite microspheres with an average diameter of 2.5 μm showed excellent monodispersity and stability in aqueous medium, strong magnetic responsiveness, high magnetite content (>68%), high saturation magnetization (58 emu g(-1)) and high efficiency in lysozyme adsorption. PMID:24492410

  13. Fe3O4/carbon coated silicon ternary hybrid composite as supercapacitor electrodes

    NASA Astrophysics Data System (ADS)

    Oh, Ilgeun; Kim, Myeongjin; Kim, Jooheon

    2015-02-01

    In this study, Fe3O4/carbon-coated Si ternary hybrid composites were fabricated. A carbon layer was directly formed on the surface of Si by the thermal vapor deposition. The carbon-coating layer not only prevented the contact between Si and reactive electrolyte but also provided anchoring sites for the deposition of Fe3O4. Fe3O4 nanoparticles were deposited on the surface of carbon-coated Si by the hydrazine reducing method. The morphology and structure of Fe3O4 and carbon layer were characterized via X-ray diffractometry, field emission scanning electron microscopy, field emission transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analyses. These characterizations indicate that a carbon layer was fully coated on the Si particles, and Fe3O4 particles were homogeneously deposited on the carbon-coated Si particles. The Fe3O4/carbon-coated Si electrode exhibited enhanced electrochemical performance, attributed to the high conductivity and stability of carbon layer and pseudocapacitive reaction of Fe3O4. The proposed ternary-hybrid composites may be potentially useful for the fabrication of high-performance electrodes.

  14. Rapid degradation of dyes in water by magnetic Fe(0)/Fe3O4/graphene composites.

    PubMed

    Chong, Shan; Zhang, Guangming; Tian, Huifang; Zhao, He

    2016-06-01

    Magnetic Fe(0)/Fe3O4/graphene has been successfully synthesized by a one-step reduction method and investigated in rapid degradation of dyes in this work. The material was characterized by N2 sorption-desorption, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), vibrating-sample magnetometer (VSM) measurements and X-ray photoelectron spectroscopy (XPS). The results indicated that Fe(0)/Fe3O4/graphene had a layered structure with Fe crystals highly dispersed in the interlayers of graphene, which could enhance the mass transfer process between Fe(0)/Fe3O4/graphene and pollutants. Fe(0)/Fe3O4/graphene exhibited ferromagnetism and could be easily separated and re-dispersed for reuse in water. Typical dyes, such as Methyl Orange, Methylene Blue and Crystal Violet, could be decolorized by Fe(0)/Fe3O4/graphene rapidly. After 20min, the decolorization efficiencies of methyl orange, methylene blue and crystal violet were 94.78%, 91.60% and 89.07%, respectively. The reaction mechanism of Fe(0)/Fe3O4/graphene with dyes mainly included adsorption and enhanced reduction by the composite. Thus, Fe(0)/Fe3O4/graphene prepared by the one-step reduction method has excellent performance in removal of dyes in water. PMID:27266311

  15. [Detection of Ethoprophos Using SERS Coupled with Magnetic Fe3O4/Ag Composite Materials].

    PubMed

    Yuan, Rong-hui; Liu, Wen-han; Teng, Yuan-jie; Nie, Jing; Ma, Su-zhen

    2015-05-01

    The magnetic Fe3O4/Ag composite materials were synthesized by reducing AgNO3 with sodium citrate in the presence of Fe3O4 which were prepared by co-precipitation firstly. The enrichment and extraction of ethoprophos assembled on Fe3O4/Ag were achieved with the applied magnetic field. The different concentrations of ethoprophos adsorbed on Fe3O4/Ag were analyzed by SERS and it was showed that the trace analysis of ethoprophos had been established, while the enhancement factor of probe molecules on Fe3O4/Ag was 1. 48 X 10(5). The structure and morphology of Fe3O4/Ag were characterized by UV-Vis, EDX and TEM. Compared with Ag, the UV-Vis absorption peak of Fe3O4/Ag shifted from 417 to 369 nm, and the UV-Vis of Fe3O4 almost had no characteristic absorption peak in this region. At the same time, it was showed that the surface properties of Fe3O4/Ag changed with Raman enhancement effect during the aggregation process of Ag around the surface of Fe3O4. Further EDX images of micro area element analysis suggested that the chemical composition of products were Ag, Fe and O while the Cu peak was from the copper mesh. In addition, TEM images indicated that the average particle size of Fe3O4 was between 30 and 60 nm with shape tended to be spherical. And the silver nanoparticles were attached to the Fe3O4 particles and agglomeration occured. Density functional theory calculations which can be applied to qualitative judgment of molecule was carried out to obtain the molecular optimization structure and theoretical Raman spectra. It was found that the stabilized SERS signals were detected under the saturated adsorption equilibrium after 15 min. Finally, Raman response of ethoprophos was achieved with lower than 2 X 10(-8) mol . L-1 , indicatint that the established method had reached the requirements of ethoprophos residues detection and could be used for analysis of sulfur-containing organophosphorus pesticide. PMID:26415443

  16. Three-dimensional Fe3O4-graphene macroscopic composites for arsenic and arsenate removal.

    PubMed

    Guo, Liangqia; Ye, Peirong; Wang, Jing; Fu, Fengfu; Wu, Zujian

    2015-11-15

    3D graphene macroscopic gel synthesized via self-assembly of GO nanosheets under basic conditions at low temperature is modified with polydopamine and Fe3O4 nanoparticles. The modification of polydopamine can not only strengthen the 3D graphene-based macroscopic architecture but also enhance the loadage and binding ability of Fe3O4 nanoparticles. The synthesized 3D Fe3O4-graphene macroscopic composites are characterized by SEM, XRD, XPS, BET, Raman and magnetic property and used as a versatile adsorbent for sub-ppm concentration of As(III) and As(V) removal from aqueous solutions. The experimental results suggest that the synthesized 3D Fe3O4-graphene macroscopic composites are promising for treating low concentration of arsenic contaminated water. PMID:26001621

  17. Robust polymer grafted Fe3O4 nanospheres for benign removal of oil from water

    NASA Astrophysics Data System (ADS)

    Madhusudhana Reddy, P.; Chang, Chi-Jung; Chen, Jem-Kun; Wu, Meng-Ting; Wang, Chih-Feng

    2016-04-01

    Removal of oil from the oil-water mixture (O-W mixture) or oil-in-water emulsions (O/W emulsion) is highly imperative. We have fabricated two series of polymer grafted iron oxide (Fe3O4) nanospheres. The oil removal efficiency of the nanospheres was found to be dependent on the grafted amount of polymers. The polystyrene grafted Fe3O4 nanospheres have shown better oil removal efficiency than the corresponding poly(butyl acrylate) grafted Fe3O4 nanospheres. The higher amount of grafted polystyrene can provide more hydrophobic character to FS series nanospheres. The FS series nanospheres exhibited higher oil-absorption capability than FB series nanospheres. Both the series of nanospheres can be recycled by simple washing method. The present results can pave the way to fabricate the robust materials for efficient absorption of various oils or organic solvents from both the oil-water mixture and oil-water emulsion.

  18. Facile synthesis of monodisperse superparamagnetic Fe3O4/PMMA composite nanospheres with high magnetization.

    PubMed

    Lan, Fang; Liu, Ke-Xia; Jiang, Wen; Zeng, Xiao-Bo; Wu, Yao; Gu, Zhong-Wei

    2011-06-01

    Monodisperse superparamagnetic Fe(3)O(4)/polymethyl methacrylate (PMMA) composite nanospheres with high saturation magnetization were successfully prepared by a facile novel miniemulsion polymerization method. The ferrofluid, MMA monomer and surfactants were co-sonicated and emulsified to form stable miniemulsion for polymerization. The samples were characterized by DLS, TEM, FTIR, XRD, TGA and VSM. The diameter of the Fe(3)O(4)/PMMA composite nanospheres by DLS was close to 90 nm with corresponding polydispersity index (PDI) as small as 0.099, which indicated that the nanospheres have excellent homogeneity in aqueous medium. The TEM results implied that the Fe(3)O(4)/PMMA composite nanospheres had a perfect core-shell structure with about 3 nm thin PMMA shells, and the core was composed of many homogeneous and closely packed Fe(3)O(4) nanoparticles. VSM and TGA showed that the Fe(3)O(4)/PMMA composite nanospheres with at least 65% high magnetite content were superparamagnetic, and the saturation magnetization was as high as around 39 emu g(-1) (total mass), which was only decreased by 17% compared with the initial bare Fe(3)O(4) nanoparticles. PMID:21454944

  19. Facile synthesis of monodisperse superparamagnetic Fe3O4/PMMA composite nanospheres with high magnetization

    NASA Astrophysics Data System (ADS)

    Lan, Fang; Liu, Ke-Xia; Jiang, Wen; Zeng, Xiao-Bo; Wu, Yao; Gu, Zhong-Wei

    2011-06-01

    Monodisperse superparamagnetic Fe3O4/polymethyl methacrylate (PMMA) composite nanospheres with high saturation magnetization were successfully prepared by a facile novel miniemulsion polymerization method. The ferrofluid, MMA monomer and surfactants were co-sonicated and emulsified to form stable miniemulsion for polymerization. The samples were characterized by DLS, TEM, FTIR, XRD, TGA and VSM. The diameter of the Fe3O4/PMMA composite nanospheres by DLS was close to 90 nm with corresponding polydispersity index (PDI) as small as 0.099, which indicated that the nanospheres have excellent homogeneity in aqueous medium. The TEM results implied that the Fe3O4/PMMA composite nanospheres had a perfect core-shell structure with about 3 nm thin PMMA shells, and the core was composed of many homogeneous and closely packed Fe3O4 nanoparticles. VSM and TGA showed that the Fe3O4/PMMA composite nanospheres with at least 65% high magnetite content were superparamagnetic, and the saturation magnetization was as high as around 39 emu g - 1 (total mass), which was only decreased by 17% compared with the initial bare Fe3O4 nanoparticles.

  20. In-Situ Preparation and Magnetic Properties of Fe3O4/WOOD Composite

    NASA Astrophysics Data System (ADS)

    Gao, Honglin; Zhang, Genlin; Wu, Guoyuan; Guan, Hongtao

    2011-06-01

    Fe3O4/wood composite, a magnetic material, was prepared by In-situ chemosynthesis method at room temperature. The X-ray diffraction (XRD) shows that the average partical size of Fe3O4 was about 14 nm. The magnetic properties of the resulting composites were investigated by vibrating sample magnetometer (VSM). The composites have saturation magnetization (Ms) values from 4.7 to 25.3 emu/g with the increase of weight percent gains (WPG) of the wood for the composites, but coercive forces (Hc) are invariable, which is different from the magnetic materials reported before. It may be due to the fact that the interaction between wood and Fe3O4 becomes stronger when less of Fe3O4 particles are introduced in the composition, and this also changes the surface anisotropy (Ks) of the magnetism. A structural characterization by Fourier transform infrared (FTIR) proved the interaction between Fe3O4 particles and wood matrix, and it also illustrates that this interaction influences the coercive force of the composite.

  1. Polymethylmethacrylate/Fe3O4 composite nanofiber membranes with ultra-low dielectric permittivity

    NASA Astrophysics Data System (ADS)

    Zhang, C. C.; Li, X.; Yang, Y.; Wang, C.

    2009-11-01

    Ultra-low dielectric permittivity poly (methyl methacrylate)/Fe3O4 composite fiber membranes have been successfully prepared using electrospinning. The composite membranes were characterized by SEM (scanning electron microscopy), TEM (transmission electron microscopy), FT-IR (Fourier transform infrared), XRD (X-ray diffraction) and a radio frequency (RF) impedance/capacitance material analyzer. The magnetic measurement showed that the composite membranes displayed the super-paramagnetic property. The results showed that the dielectric permittivity of the composite fiber membranes was decreasing with increasing Fe3O4 nanoparticle content.

  2. Biocompatibility of Fe3O4@Au composite magnetic nanoparticles in vitro and in vivo

    PubMed Central

    Li, Yuntao; Liu, Jing; Zhong, Yuejiao; Zhang, Jia; Wang, Ziyu; Wang, Li; An, Yanli; Lin, Mei; Gao, Zhiqiang; Zhang, Dongsheng

    2011-01-01

    Purpose This research was conducted to assess the biocompatibility of the core–shell Fe3O4@ Au composite magnetic nanoparticles (MNPs), which have potential application in tumor hyperthermia. Methods Fe3O4@Au composite MNPs with core–shell structure were synthesized by reduction of Au3+ in the presence of Fe3O4-MNPs prepared by improved co-precipitation. Cytotoxicity assay, hemolysis test, micronucleus (MN) assay, and detection of acute toxicity in mice and beagle dogs were then carried out. Results The result of cytotoxicity assay showed that the toxicity grade of this material on mouse fibroblast cell line (L-929) was classified as grade 1, which belongs to no cytotoxicity. Hemolysis rates showed 0.278%, 0.232%, and 0.197%, far less than 5%, after treatment with different concentrations of Fe3O4@Au composite MNPs. In the MN assay, there was no significant difference in MN formation rates between the experimental groups and negative control (P > 0.05), but there was a significant difference between the experimental groups and the positive control (P < 0.05). The median lethal dose of the Fe3O4@Au composite MNPs after intraperitoneal administration in mice was 8.39 g/kg, and the 95% confidence interval was 6.58–10.72 g/kg, suggesting that these nanoparticles have a wide safety margin. Acute toxicity testing in beagle dogs also showed no significant difference in body weight between the treatment groups at 1, 2, 3, and 4 weeks after liver injection and no behavioral changes. Furthermore, blood parameters, autopsy, and histopathological studies in the experimental group showed no significant difference compared with the control group. Conclusion The results indicate that Fe3O4@Au composite MNPs appear to be highly biocompatible and safe nanoparticles that are suitable for further application in tumor hyperthermia. PMID:22131827

  3. Uniform Superparamagnetic Fe3O4/CMCS Composite Nanospheres for Lysozyme Adsorption.

    PubMed

    Yang, Qi; Lan, Fang; Liu, Ziyao; Ma, Shaohua; Li, Wenliao; Wu, Yao; Gu, Zhongwei

    2016-03-01

    In this study, uniform superparamagnetic Fe3O4/carboxymethyl chitosan composite nanospheres with high saturation magnetization were successfully synthesized via a modified inverse emulsion crosslinking approach, using genipin as a cross-linking agent. These nanospheres were then characterized, and their protein adsorption capacity was further investigated under various conditions. The implementation of a sonication treatment of a mixture containing Fe3O4 nanoparticles and carboxymethyl chitosan before the emulsion process significantly promoted the homogeneity of Fe3O4 nanoparticles in an aqueous phase system. The Fe3O4/carboxymethyl chitosan composite nanospheres were of uniform spherical structure, were approximately 230 nm in size, and possessed superparamagnetic characteristics with a mean saturation magnetization as high as 35 emu g(-1), corresponding to a magnetite content of 43%. Lysozyme was then employed as a model protein to investigate the effects of pH, incubation time and ion strength on the protein adsorption capacity of the as-synthesized composite nanospheres. The as-obtained composite nanospheres could serve as a promising candidate for fast and efficient protein adsorption. PMID:27455623

  4. Synthesis of Fe3O4/Polyacrylonitrile Composite Electrospun Nanofiber Mat for Effective Adsorption of Tetracycline.

    PubMed

    Liu, Qing; Zhong, Lu-Bin; Zhao, Quan-Bao; Frear, Craig; Zheng, Yu-Ming

    2015-07-15

    Novel Fe3O4/polyacrylonitrile (PAN) composite nanofibers (NFs) were prepared by a simple two-step process, an electrospinning and solvothermal method. Characterization by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) demonstrated formation of a uniform nanoparticles coating (about 20 nm in thickness) on the PAN nanofiber backbone. The coating was constructed by well-crystallized cubic phase Fe3O4 nanoparticles as examined by X-ray diffraction spectroscopy (XRD). The coating doubled the specific surface area of NFs, from 8.4 to 17.8 m2 g(-1), as confirmed by nitrogen sorption isotherm analysis. To evaluate the feasibility of Fe3O4/PAN composite NFs as a potential adsorbent for antibiotic removal, batch adsorption experiments were conducted using tetracycline (TC) as the model antibiotic molecule. The results showed that Fe3O4/PAN composite NFs were effective in removing TC with no impactful loss of Fe in the pH regime of environmental interest (5-8). The adsorption of TC onto Fe3O4/PAN composite NFs better fitted the pseudo-second-order kinetics model, and the maximum adsorption capacity calculated from Langmuir isotherm model was 257.07 mg g(-1) at pH 6. The composite NFs also exhibited good regenerability over repeated adsorption/desorption cycles. Surface complexation between TC and the composite NFs contributed most to the adsorption as elucidated by X-ray photoelectron spectroscopy (XPS). This highly effective and novel adsorbent can be easily modularized and separated, promising its huge potential in drinking and wastewater treatment for antibiotic removal. PMID:26079116

  5. Lightweight, multifunctional polyetherimide/graphene@Fe3O4 composite foams for shielding of electromagnetic pollution.

    PubMed

    Shen, Bin; Zhai, Wentao; Tao, Mimi; Ling, Jianqiang; Zheng, Wenge

    2013-11-13

    Novel high-performance polyetherimide (PEI)/graphene@Fe3O4 (G@Fe3O4) composite foams with flexible character and low density of about 0.28-0.4 g/cm(3) have been developed by using a phase separation method. The obtained PEI/G@Fe3O4 foam with G@Fe3O4 loading of 10 wt % exhibited excellent specific EMI shielding effectiveness (EMI SE) of ~41.5 dB/(g/cm(3)) at 8-12 GHz. Moreover, most the applied microwave was verified to be absorbed rather than being reflected back, resulting from the improved impedance matching, electromagnetic wave attenuation, as well as multiple reflections. Meanwhile, the resulting foams also possessed a superparamagnetic behavior and low thermal conductiviy of 0.042-0.071 W/(m K). This technique is fast, highly reproducible, and scalable, which may facilitate the commercialization of such composite foams and generalize the use of them as EMI shielding materials in the fields of spacecraft and aircraft. PMID:24134429

  6. Magnetic quenching of photonic activity in Fe3O4-elastomer composite

    NASA Astrophysics Data System (ADS)

    Ma, Danhao; Hess, Dustin T.; Shetty, Pralav P.; Adu, Kofi W.; Bell, Richard C.; Terrones, Mauricio

    2016-01-01

    We report a quenching phenomenon within the visible region of the electromagnetic spectrum in the photonic response of a passive Fe3O4-silicone elastomer composite film due to magnetically aligned Fe3O4 nanoparticles. We performed systematic studies of the polarization dependence, the effect of particle size, and an in- and out-of-plane particle alignment on the optical response of the Fe3O4-silicone elastomer composites using a UV/vis/NIR spectrometer. We observed systematic redshifts in the response of the out-of-plane composite films with increasing particle alignment and weight that are attributed to dipole-induced effects. There were no observable shifts in the spectra of the in-plane films, suggesting the orientation of the magnetic dipole and the induced electric dipole play a crucial role in the optical response. A dramatic suppression to near quenching of the photonic response occurred in films containing moderate concentrations of the aligned nanoparticles. This is attributed to the interplay between the intra- and the interparticle dipoles. This occurred even when low magnetic fields were used during the curing process, suggesting that particle alignment and particle size limitation are critical in the manipulation of the photonic properties. A dipole approximation model is used to explain the quenching phenomenon. An active system of such a composite has a potential application in magneto-optic switches.

  7. Preparation and Microwave Absorption Properties of Novel Carbon Nanofiber/Fe3O4 Composites.

    PubMed

    Ren, Yong; Dai, Bo; Wang, Gai-Hua; Zhang, Xiao-Wei; Zhu, Pei; Li, Shi-Rong

    2015-04-01

    Novel, carbonized bacterial cellulose (CBC)/Fe3O4 nanocomposites were synthesized using vacuum filtration and annealing (VFA) methods. The as-synthesized products were characterized by scanning electron microscopy, vibrating sample magnetometry, and transmission electron microscopy. The complex permittivity and permeability of Fe3O4-CBC (5 wt.% CBC)/paraffin wax composites were measured by vector network analysis. To study the microwave absorption (MA) performances, we compared the VFA products with the vacuum filtration (VF) products. The VFA products exhibited better absorption performances because of their larger dielectric loss. When the matching thickness was 2.4 mm, the calculated reflection loss reached a minimum value of -27 dB when VFA was used and a value of -11 dB when VF was used. The wide-range MA properties of these materials lead to potential applications in MA fields. PMID:26353503

  8. One-step solvothermal synthesis of magnetic Fe3O4-graphite composite for Fenton-like degradation of levofloxacin.

    PubMed

    Wang, Long; Zhao, Qi; Hou, Juan; Yan, Jin; Zhang, Fengshuang; Zhao, Jiahui; Ding, Hong; Li, Yi; Ding, Lan

    2016-01-01

    A novel Fe3O4-graphite composite was prepared, characterized, and investigated as a heterogeneous Fenton-like catalyst for the degradation of levofloxacin (LEV) in an aqueous solution. The results revealed that the Fe3O4-graphite composite exhibited excellent properties for the degradation and mineralization of LEV, achieving a nearly complete degradation of 50 mg L(-1) LEV in 15 min and 48% of total organic carbon removal in 60 min under optimal conditions. A large electronic conjugation structure exists in graphite, which may lead to the fast production of •OH radical species because of the easy reduction of Fe(III) to Fe(II). In addition, we observed that the graphite can degrade LEV in the presence of H2O2. Therefore, the synergistic results of the graphite structure and Fe3O4 magnetic nanoparticles (MNPs) may contribute to the high catalytic activity of the Fe3O4-graphite composite. Compared with pure Fe3O4 MNPs, lesser iron leaching of the Fe3O4-graphite composite was observed during the degradation of LEV. The degradation efficiency of LEV remained approximately 80% at the fifth recycling run, which indicates that the Fe3O4-graphite composite has potential applications in water treatment for removing organic pollutants. PMID:26513011

  9. Facile Synthesis of Fe3O4/GCs Composites and Their Enhanced Microwave Absorption Properties.

    PubMed

    Jian, Xian; Wu, Biao; Wei, Yufeng; Dou, Shi Xue; Wang, Xiaolin; He, Weidong; Mahmood, Nasir

    2016-03-01

    Graphene has good stability and adjustable dielectric properties along with tunable morphologies, and hence can be used to design novel and high-performance functional materials. Here, we have reported a facile synthesis method of nanoscale Fe3O4/graphene capsules (GCs) composites using the combination of catalytic chemical vapor deposition (CCVD) and hydrothermal process. The resulting composite has the advantage of unique morphology that offers better synergism among the Fe3O4 particles as well as particles and GCs. The microwave-absorbing characteristics of developed composites were investigated through experimentally measured electromagnetic properties and simulation studies based on the transmission line theory, explained on the basis of eddy current, natural and exchange resonance, as well as dielectric relaxation processes. The composites bear minimum RL value of -32 dB at 8.76 GHz along with the absorption bandwidth range from 5.4 to 17 GHz for RL lower than -10 dB. The better performance of the composite based on the reasonable impedance characteristic, existence of interfaces around the composites, and the polarization of free carriers in 3D GCs that make the as-prepared composites capable of absorbing microwave more effectively. These results offer an effective way to design high-performance functional materials to facilitate the research in electromagnetic shielding and microwave absorption. PMID:26890224

  10. Synthesis of Fe3O4-graphene-TiO2 ternary composite networks for enhanced capture of phosphopeptides.

    PubMed

    Min, Qianhao; Zhang, Xiaoxia; Zhang, Hongyi; Zhou, Fang; Zhu, Jun-Jie

    2011-11-14

    Fe(3)O(4)-graphene-TiO(2) ternary composite networks were first synthesized, which exhibited high selectivity and capacity in the capture of phosphopeptides, due to the enhanced contact to phosphopeptides given by the graphene scaffold. PMID:21952172

  11. Gel-limited synthesis of dumbbell-like Fe3O4-Ag composite microspheres and their SERS applications.

    PubMed

    Zhang, Xiaoli; Niu, Chunyu; Wang, Yongqiang; Zhou, Shaomin; Liu, Jin

    2014-11-01

    A novel gel-limited strategy was developed to synthesize dumbbell-like Fe3O4-Ag composite microspheres through a simple one-pot solvothermal method. In such a reaction system, a special precursor solution containing oleic, water, ethanol and silver ions was used and transformed into a bulk gel under heating at the very beginning of the reaction, thus all the subsequent reactions proceeded in the interior of the gel. The gel-limited reactions had two advantages, on the one hand, the magnetic Fe3O4 microspheres were fixed in the gel which avoided them aggregating together, whereas on the other hand, the silver ions stored in the gel could be gradually released and tended to diffuse towards the nearest Fe3O4 microsphere, which favored the generation of a dumbbell-like Fe3O4-Ag structure. From the time-dependent experiments under optimal conditions, the typical growth process of dumbbell-like structures clearly demonstrated that a silver seed first appeared on the surface of a single Fe3O4 microsphere, which then grew bigger slowly and finally formed a dumbbell-like Fe3O4-Ag structure. Moreover, the formation of the gel was found to be strongly affected by the ratio of water and ethanol in the precursor solution, which further influenced the morphologies of the Fe3O4-Ag microspheres. Furthermore, the effect of lattice match between Fe3O4 and Ag on the final products was also proven from the control experiments by using a template with a different surface crystalline structure. When used as SERS substrates, the final dumbbell-like Fe3O4-Ag microspheres show fast magnetic separation and the selective detection of thiram for the surface capped oleic chain during the growth process. PMID:25188029

  12. Interface composition between Fe3O4 nanoparticles and GaAs for spintronic applications

    NASA Astrophysics Data System (ADS)

    Hihath, Sahar; Kiehl, Richard A.; Benthem, Klaus van

    2014-08-01

    Recent interest in spintronic applications has necessitated the study of magnetic materials in contact with semiconductor substrates; importantly, the structure and composition of these interfaces can influence both device functionality and the magnetic properties. Nanoscale ferromagnet/semiconductor structures are of particular interest. In this study, the interface structure between a monolayer of ferromagnetic magnetite (Fe3O4) nanoparticles and a GaAs substrate was studied using cross-sectional transmission electron microscopy techniques. It was found that a continuous amorphous oxide interface layer separates the nanoparticles from the GaAs substrate, and that iron diffused into the interface layer forming a compositional gradient. Electron energy-loss near-edge fine structures of the O K absorption edge revealed that the amorphous oxide is composed of γ-Fe2O3 directly underneath the Fe3O4 nanoparticles, followed by a solid solution of Ga2O3 and FeO and mostly Ga2O3 when approaching the buckled oxide/substrate interface. Real-space density functional theory calculations of the dynamical form factor confirmed the experimental observations. The implication of the findings on the optimization of these structures for spin injection is discussed.

  13. One-step preparation of Fe3O4/Pd@polypyrrole composites with enhanced catalytic activity and stability.

    PubMed

    Zhang, Hui; Liu, Yang; Wu, Jie; Xin, Baifu

    2016-08-15

    Core/shell Fe3O4/Pd@polypyrrole (PPy) composites with a Fe3O4 core and a PPy shell embedding Pd nanoparticles were prepared in one-step. The diameter of highly dispersed Pd nanoparticles was as small as 2.9nm owing to coordination interaction generated between Pd(2+) ions and amino groups on PPy chains. The outer PPy shell was only 6.8nm: on one hand, the coverage was beneficial to improving the stability of resulting composites; on the other hand, the shell was thin enough to permit free contact between embedding Pd nanoparticles and reactants. Additionally, the as-prepared Fe3O4/Pd@PPy composites displayed good magnetic separation property due to incorporation of Fe3O4 nanospheres. Based on above merits, they served as suitable catalyst candidates. Their catalytic performance and reusability were evaluated by reduction of 4-nitrophenol with sodium borohydride as reducing agent. Compared with traditional Fe3O4/Pd composites, Fe3O4/Pd@PPy composites not only showed superior catalytic activity; but also exhibited much better stability in successive cycling tests. PMID:27232537

  14. Multifunctional properties of cyanate ester composites with SiO2 coated Fe3O4 fillers.

    PubMed

    Sun, Weixing; Sun, Wuzhu; Kessler, Michael R; Bowler, Nicola; Dennis, Kevin W; McCallum, R William; Li, Qi; Tan, Xiaoli

    2013-03-13

    SiO2 coated Fe3O4 submicrometer spherical particles (a conducting core/insulating shell configuration) are fabricated using a hydrothermal method and are loaded at 10 and 20 vol % into a bisphenol E cyanate ester matrix for synthesis of multifunctional composites. The dielectric constant of the resulting composites is found to be enhanced over a wide frequency and temperature range while the low dielectric loss tangent of the neat cyanate ester polymer is largely preserved up to 160 °C due to the insulating SiO2 coating on individual conductive Fe3O4 submicrometer spheres. These composites also demonstrate high dielectric breakdown strengths at room temperature. Dynamic mechanical analysis indicates that the storage modulus of the composite with a 20 vol % filler loading is twice as high as that of neat resin, but the glass transition temperature considerably decreases with increasing filler content. Magnetic measurements reveal a large saturation magnetization and negligibly low coercivity and remanent magnetization in these composites. PMID:23431998

  15. Multifunctional Properties of Cyanate Ester Composites with SiO2 Coated Fe3O4 Fillers

    SciTech Connect

    Sun, Weixing; Sun, Wuzhu; Kessler, Michael R; Bowler, Nicola; Dennis, Kevin W; McCallum, R William; Li, Qi; Tan, Xiaoli

    2013-02-22

    SiO2 coated Fe3O4 submicrometer spherical particles (a conducting core/insulating shell configuration) are fabricated using a hydrothermal method and are loaded at 10 and 20 vol % into a bisphenol E cyanate ester matrix for synthesis of multifunctional composites. The dielectric constant of the resulting composites is found to be enhanced over a wide frequency and temperature range while the low dielectric loss tangent of the neat cyanate ester polymer is largely preserved up to 160 ?C due to the insulating SiO2 coating on individual conductive Fe3O4 submicrometer spheres. These composites also demonstrate high dielectric breakdown strengths at room temperature. Dynamic mechanical analysis indicates that the storage modulus of the composite with a 20 vol % filler loading is twice as high as that of neat resin, but the glass transition temperature considerably decreases with increasing filler content. Magnetic measurements reveal a large saturation magnetization and negligibly low coercivity and remanent magnetization in these composites.

  16. A mild synthetic route to Fe3O4@TiO2-Au composites: preparation, characterization and photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Ma, Jianqi; Guo, Shaobo; Guo, Xiaohua; Ge, Hongguang

    2015-10-01

    To prevent and avoid magnetic loss caused by magnetite core phase transitions involved in high-temperature crystallization of sol-gel TiO2, a direct and feasible low-temperature crystallization technique was developed to deposit anatase TiO2 nanoparticle shell on Fe3O4 sphere cores. To promote the photocatalytic efficiency of the obtained core-shell Fe3O4@TiO2 magnetic photocatalyst, uniformly distributed Au nanoparticles (NPs) were successfully immobilized on the core-shell Fe3O4@TiO2 spheres via a seed-mediated growth procedure. The 3 nm Au colloid absorbed on Fe3O4@TiO2 served as a nucleation site for the growth of Au NPs overlayer. The morphology, structure, composition and magnetism of the resulting composites were characterized, and their photocatalytic activities were also evaluated. In comparison to Fe3O4@TiO2, Fe3O4@TiO2-Au exhibited higher photocatalytic activity for organic degradation under UV irradiation. This enhanced mechanism may have resulted from efficient charge separation of photogenerated electrons and holes due to the Au NPs attached on the TiO2. In addition, the composites possessed superparamagnetic properties with a high saturation magnetization of 44.6 emu g-1 and could be easily separated and recycled by a magnet.

  17. Fe3O4/cyclodextrin polymer nanocomposites for selective heavy metals removal from industrial wastewater.

    PubMed

    Badruddoza, Abu Zayed M; Shawon, Zayed Bin Zakir; Tay, Wei Jin Daniel; Hidajat, Kus; Uddin, Mohammad Shahab

    2013-01-01

    In this work, carboxymethyl-β-cyclodextrin (CM-β-CD) polymer modified Fe(3)O(4) nanoparticles (CDpoly-MNPs) was synthesized for selective removal of Pb(2+), Cd(2+), Ni(2+) ions from water. This magnetic adsorbent was characterized by TEM, FTIR, XPS and VSM. The adsorption of all studied metal ions onto CDpoly-MNPs was found to be dependent on pH, ionic strength, and temperature. Batch adsorption equilibrium was reached in 45 min and maximum uptakes for Pb(2+), Cd(2+) and Ni(2+) in non-competitive adsorption mode were 64.5, 27.7 and 13.2 mg g(-1), respectively at 25 °C. Adsorption data were fitted well to Langmuir isotherm and pseudo-second-order models for kinetic study. The polymer grafted on MNPs enhanced the adsorption capacity because of the complexing abilities of the multiple hydroxyl and carboxyl groups in polymer backbone with metal ions. In competitive adsorption experiments, CDpoly-MNPs could preferentially adsorb Pb(2+) ions with an affinity order of Pb(2+)>Cd(2+)>Ni(2+) which can be explained by hard and soft acids and bases (HASB) theory. Furthermore, we explored the recyclability of CDpoly-MNPs. PMID:23044139

  18. Facile and straightforward synthesis of superparamagnetic reduced graphene oxide-Fe3O4 hybrid composite by a solvothermal reaction.

    PubMed

    Liu, Yue-Wen; Guan, Meng-Xue; Feng, Lan; Deng, Shun-Liu; Bao, Jian-Feng; Xie, Su-Yuan; Chen, Zhong; Huang, Rong-Bin; Zheng, Lan-Sun

    2013-01-18

    A superparamagnetic reduced graphene oxide-Fe(3)O(4) hybrid composite (rGO-Fe(3)O(4)) was prepared via a facile and straightforward method through the solvothermal reaction of iron (III) acetylacetonate (Fe(acac)(3)) and graphene oxide (GO) in ethylenediamine (EDA) and water. By this method, chemical reduction of GO as well as the formation of Fe(3)O(4) nanoparticles (NPs) can be achieved in one step. The Fe(3)O(4) NPs are firmly deposited on the surfaces of rGO, avoiding their reassembly to graphite. The rGO sheets prevent the agglomeration of Fe(3)O(4) NPs and enable a uniform dispersion of these metal oxide particles. The size distribution and coverage density of Fe(3)O(4) NPs deposited on rGO can be controlled by varying the initial mass ratio of GO and iron precursor, Fe(acac)(3). With an initial mass ratio of GO and Fe(acac)(3) of 5:5, the surfaces of rGO sheets are densely covered by spherical Fe(3)O(4) NPs with an average size of 19.9 nm. The magnetic-functionalized rGO hybrid exhibits a good magnetic property and the specific saturation magnetization (M(s)) is 13.2 emu g(-1). The adsorption test of methylene blue from aqueous solution demonstrates the potential application of this rGO-Fe(3)O(4) hybrid composite in removing organic dyes from polluted water. PMID:23220906

  19. Microwave absorption properties and mechanism for hollow Fe3 O4 nanosphere composites

    NASA Astrophysics Data System (ADS)

    Li, Z. W.; Yang, Z. H.

    2015-08-01

    Hollow Fe3 O4 nanospheres with the diameter of 450 nm and the wall thickness of 80 nm are prepared using the Ostwald ripening process. The composites filled with the hollow nanospheres of 60 wt% have good high-frequency and absorption properties. In RL-f curves, two absorption frequencies are found, which have their origins in quarter-wavelength resonator and magnetic resonance, respectively. Based on the quarter-wavelength resonator model, the calculated fA1 and RLA1 are in a good agreement with the observed values. Due to the overlap of the two absorptions, the frequency band is expanded. The composite with light weight of the density of 2.71 g/cm3 has bandwidth WP of 65% with return loss RL ≤ - 10 dB at thickness of 0.3 cm for EM absorption or attenuation applications.

  20. One pot synthesis and characterization of Fe3O4 Nanorod-PNIPA Nanogel Composite for protein adsorption.

    PubMed

    Rajar, Kausar; Karakus, Baris; Koc, Kenan; Alveroglu, Esra

    2016-11-01

    In this study, Fe3O4 Nanorod-PNIPA Nanogel Composite nanomaterial is synthesized, characterized and used for lysozyme adsorption. XRD, ATR-FTIR, AFM and SEM measurements reveal that nanorods-nanogels composite was prepared successfully. The diameter of nanorods and the average particle size of nanogels are found around 150nm and 300nm, respectively. VSM measurement shows that the Fe3O4 particles are in rod shape and has superparamagnetic behavior, no hysteresis and remnant is detected. The adsorption kinetic of lysozyme on composite material is studied via fluorescence method, and the adsorption reaction rate constant is calculated as 0.904s(-1) by using Langmuir-Hinshelwood pseudo second order model. Fe3O4 Nanorod-PNIPA Nanogel Composite is appeared as a fast catalyst for lysozyme like protein immobilization. PMID:27523996

  1. A solvothermal method to produce RGO-Fe3O4 hybrid composite for fast chromium removal from aqueous solution

    NASA Astrophysics Data System (ADS)

    Zhou, Li; Deng, Huiping; Wan, Junli; Shi, Jun; Su, Tong

    2013-10-01

    A simple one step solvotermal strategy using non-toxic and cost-effective precursors has been developed to prepare reduced graphene oxide (RGO)-Fe3O4 non-nanocomposite for removal of Cr(VI). Compared with the nano-adsorbent, the RGO-Fe3O4 hybrid particles with size larger than 100 nm can reduce cell toxicity in water treatment processes. The structure, surface and magnetic characteristics of the non-nanocomposite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and Vibrating sample magnetometer (VSM). The RGO-Fe3O4 composite with the highest loading of Fe3O4 demonstrates the fastest removal of 500 μg/L Cr(VI) which can reach 85% within 5 min at neutral pH. The adsorption kinetics follows the pseudo-second-order model and the adosorbent exhibits better Cr(VI) removal efficiency in water at low pH. However, the removal efficiency of Cr(VI) decreased when common hazardous ions were added in water. The large saturation magnetization (41.12 emu/g) of the synthesized non-nanoparticles allows fast separation of the adsorbent from water. The RGO-Fe3O4 non-nanocomposite could be utilized as an efficient, stable, less toxic and magnetically separable adsorbent for environmental cleanup.

  2. Preparation and drug-loading properties of Fe3O4/Poly(styrene-co-acrylic acid) magnetic polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Lu, Wensheng; Shen, Yuhua; Xie, Anjian; Zhang, Weiqiang

    2013-11-01

    Fe3O4/poly(styrene-co-acrylic acid) magnetic polymer nanocomposites were synthesized by the dispersion polymerization method using styrene as hard monomer, acrylic acid as functional monomer, Fe3O4 nanoparticles modified with oleic acid as core, and poly(styrene-co-acrylic acid) as shell. Drug-loading properties of magnetic polymer nanocomposites with curcumin as a model drug were also studied. The results indicated that magnetic polymer nanocomposites with monodisperse were obtained, the particle size distribution was 50-120 nm, and the average size was about 100 nm. The contents of poly(styrene-co-acrylic acid) and Fe3O4 nanoparticles in magnetic polymer nanocomposites were 74% and 24.7%, respectively. The drug-loading capacity and entrapment efficiency were 2.5% and 44.4%, respectively. The saturation magnetization of magnetic polymer nanocomposites at 300 K was 20.2 emu/g without coercivity and remanence. The as-prepared magnetic polymer nanocomposites have not only lots of functional carboxyl groups but also stronger magnetic response, which might have potential applications in drug carrier and targeted drug release.

  3. Photothermally actuated interfacial hydration for fast friction switch on hydrophilic polymer brush modified PDMS sheet incorporated with Fe3O4 nanoparticles.

    PubMed

    Liu, Guoqiang; Cai, Meirong; Feng, Yange; Wang, Xiaolong; Zhou, Feng; Liu, Weimin

    2016-03-01

    A near-infrared light triggered fast interfacial friction switch was achieved with polyelectrolyte brush grafted PDMS embedded with Fe3O4 nanoparticles, where the in situ heating up of the photothermal Fe3O4 nanoparticles in the polymer matrix changes the interface humidity and thereafter alters the hydration level of the interfacial polymer brushes. PMID:26856309

  4. Arsenic Removal from Aqueous Solutions Using Fe3O4-HBC Composite: Effect of Calcination on Adsorbents Performance

    PubMed Central

    Baig, Shams Ali; Sheng, TianTian; Sun, Chen; Xue, XiaoQin; Tan, LiSha; Xu, XinHua

    2014-01-01

    The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C) and environment (air and nitrogen) were investigated for the adsorptive removal of As(V) and As(III) from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4) via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH) was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2)>Fe3O4-HBC (uncalcined)>Fe3O4-HBC-400°C(N2)>Fe3O4-HBC-400°C(air)>Fe3O4-HBC-1000°C(air) and the maximum As(V) and As(III) adsorption capacities were found to be about 3.35 mg g−1 and 3.07 mg g−1, respectively. The adsorption of As(V) and As(III) remained stable in a wider pH range (4–10) using Fe3O4-HBC-1000°C(N2). Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99) rather than pseudo-first-order kinetics model. The adsorption of As(V) and As(III) onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher) strongly inhibited As(V) and As(III) removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water. PMID:24967645

  5. Hybrid composites made of multiwalled carbon nanotubes functionalized with Fe3O4 nanoparticles for tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Cunha, C.; Panseri, S.; Iannazzo, D.; Piperno, A.; Pistone, A.; Fazio, M.; Russo, A.; Marcacci, M.; Galvagno, S.

    2012-11-01

    A straightforward technique for functionalization of multiwalled carbon nanotubes (MWCNTs) with magnetite (Fe3O4) nanoparticles was developed. Iron oxide nanoparticles were deposited on MWCNT surfaces by a deposition-precipitation method using Fe3+/Fe2+ salts precursors in basic solution. The characterizations by HRTEM, XRD, SEM/EDX, AAS and TPR analyses confirmed the successful formation of magnetic iron oxide nanoparticles on the MWCNT surface. Fe3O4/MWCNT hybrid composites were analysed in vitro by incubation with mesenchymal stem cells for 1, 3 and 7 days, either in the presence or absence of a static magnetic field. Analysis of cell proliferation was performed by the MTT assay, quantification of cellular stress was performed by the Lactate Dehydrogenase assay and analysis of cell morphology was performed by actin immunofluorescence and scanning electron microscopy. Results demonstrate that the introduction of magnetite into the MWCNT structure increases biocompatibility of oxidized MWCNTs. In addition, the presence of a static magnetic field further increases Fe3O4/MWCNT influence on cell behaviour. These results demonstrate this novel Fe3O4/MWCNT hybrid composite has good potential for tissue engineering applications.

  6. Synthesis of magnetic porous Fe3O4/C/Cu2O composite as an excellent photo-Fenton catalyst under neutral condition.

    PubMed

    Chai, Fanfan; Li, Keyan; Song, Chunshan; Guo, Xinwen

    2016-08-01

    Magnetic porous Fe3O4/C/Cu2O composites were prepared by a simple two-step process. Porous Fe3O4/C was synthesized via calcining iron tartrate precursor and then Cu2O was composited with Fe3O4/C by a precipitation-reduction method. The as-prepared samples were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) elemental mapping. Results show that Fe3O4/C has porous nanorod structure, which is composed of numerous small nanoparticles of about 50nm. Fe3O4 and carbon are uniformly distributed in the Fe3O4/C/Cu2O composite and Cu2O is dispersed on the surface of Fe3O4/C. Fe3O4/C/Cu2O composite exhibits excellent photo-Fenton catalytic performance for the degradation of methylene blue (MB) under visible light irradiation and neutral pH conditions, and MB (100mg/L) could be almost completely removed within 60min. The composite shows good recyclability and could be conveniently separated by an applied magnetic field. These results demonstrate that the Fe3O4/C/Cu2O composite is a powerful Fenton-like catalyst for degradation of organic pollutants from wastewater. PMID:27161809

  7. A facile synthesis of Fe3O4-charcoal composite for the sorption of a hazardous dye from aquatic environment.

    PubMed

    Ahmed, Md Juned K; Ahmaruzzaman, M

    2015-11-01

    Herein, we synthesized Fe3O4-charcoal composite using chemical precipitation technique and utilized it for the sorption of methylene blue from aqueous solution. The synthesized composite was characterized by Infra-red spectroscopy, N2 adsorption-desorption isotherm, X-ray diffraction, selected area electron diffraction, transmission electron microscopy, and vibrating sample magnetometer. The composite depicts absorption bands conforming to Fe-O, -OH, CO, and C-O vibrations. The composite was mesoporous in nature with a surface area of 387.30 m(2) g(-1). The observed diffraction planes correspond to face-centered cubic Fe3O4 and disordered graphitic carbon. The spherical Fe3O4 particles (average diameter ∼13.8 nm) were uniformly distributed in the carbon matrix of the charcoal. The saturation and remanent magnetizations demonstrate its potential for magnetic separation and reuse. The composite showed dye sorption capacities of 97.49 mg g(-1) and 90.85 mg g(-1) in batch and fixed-bed system. Pseudo-second order kinetics and Temkin isotherm best represented the sorption data. The sorption process was endothermic, spontaneous, and administered by electrostatic, π-π dispersive interactions, film, and intraparticle diffusion. Microwave irradiations followed by methanol elution regenerated the dye-loaded composite with nearly no loss in sorption capacity. The recovery of energy and potential utilization of bottom ash enhances the prospective of Fe3O4-charcoal composite for industrial applications. PMID:26320009

  8. Activated carbon/Fe(3)O(4) nanoparticle composite: fabrication, methyl orange removal and regeneration by hydrogen peroxide.

    PubMed

    Do, Manh Huy; Phan, Ngoc Hoa; Nguyen, Thi Dung; Pham, Thi Thu Suong; Nguyen, Van Khoa; Vu, Thi Thuy Trang; Nguyen, Thi Kim Phuong

    2011-11-01

    In the water treatment field, activated carbons (ACs) have wide applications in adsorptions. However, the applications are limited by difficulties encountered in separation and regeneration processes. Here, activated carbon/Fe(3)O(4) nanoparticle composites, which combine the adsorption features of powdered activated carbon (PAC) with the magnetic and excellent catalytic properties of Fe(3)O(4) nanoparticles, were fabricated by a modified impregnation method using HNO(3) as the carbon modifying agent. The obtained composites were characterized by X-ray diffraction, scanning and transmission electron microscopy, nitrogen adsorption isotherms and vibrating sample magnetometer. Their performance for methyl orange (MO) removal by adsorption was evaluated. The regeneration of the composite and PAC-HNO(3) (powdered activated carbon modified by HNO(3)) adsorbed MO by hydrogen peroxide was investigated. The composites had a high specific surface area and porosity and a superparamagnetic property that shows they can be manipulated by an external magnetic field. Adsorption experiments showed that the MO sorption process on the composites followed pseudo-second order kinetic model and the adsorption isotherm date could be simulated with both the Freundlich and Langmuir models. The regeneration indicated that the presence of the Fe(3)O(4) nanoparticles is important for a achieving high regeneration efficiency by hydrogen peroxide. PMID:21840037

  9. The Influence of Nano-Fe3O4 on the Microstructure and Mechanical Properties of Cementitious Composites.

    PubMed

    Sikora, Pawel; Horszczaruk, Elzbieta; Cendrowski, Krzysztof; Mijowska, Ewa

    2016-12-01

    In the last decade, nanotechnology has been gathering a spectacular amount of attention in the field of building materials. The incorporation of nanosized particles in a small amount to the building materials can influence their properties significantly. And it can contribute to the creation of novel and sustainable structures. In this work, the effect of nano-Fe3O4 as an admixture (from 1 to 5 wt.% in mass of the cement) on the mechanical and microstructural properties of cementitious composites has been characterised. The study showed that Fe3O4 nanoparticles acted as a filler which improved the microstructure of a cementitious composite and reduced its total porosity, thus increasing the density of the composite. The presence of nanomagnetite did not affect the main hydration products and the rate of cement hydration. In addition, the samples containing nanomagnetite exhibited compressive strength improvement (up to 20 %). The study showed that 3 wt.% of nano-Fe3O4 in the cementitious composite was the optimal amount to improve both its mechanical and microstructural properties. PMID:27067730

  10. The Influence of Nano-Fe3O4 on the Microstructure and Mechanical Properties of Cementitious Composites

    NASA Astrophysics Data System (ADS)

    Sikora, Pawel; Horszczaruk, Elzbieta; Cendrowski, Krzysztof; Mijowska, Ewa

    2016-04-01

    In the last decade, nanotechnology has been gathering a spectacular amount of attention in the field of building materials. The incorporation of nanosized particles in a small amount to the building materials can influence their properties significantly. And it can contribute to the creation of novel and sustainable structures. In this work, the effect of nano-Fe3O4 as an admixture (from 1 to 5 wt.% in mass of the cement) on the mechanical and microstructural properties of cementitious composites has been characterised. The study showed that Fe3O4 nanoparticles acted as a filler which improved the microstructure of a cementitious composite and reduced its total porosity, thus increasing the density of the composite. The presence of nanomagnetite did not affect the main hydration products and the rate of cement hydration. In addition, the samples containing nanomagnetite exhibited compressive strength improvement (up to 20 %). The study showed that 3 wt.% of nano-Fe3O4 in the cementitious composite was the optimal amount to improve both its mechanical and microstructural properties.

  11. Synthesis of Fe3O4/graphene/TiO2 composites for the highly selective enrichment of phosphopeptides from biological samples.

    PubMed

    Lu, Jin; Deng, Chunhui; Zhang, Xiangmin; Yang, Pengyuan

    2013-08-14

    In this work, Fe3O4/graphene/TiO2 composites with a large surface area were designed and synthesized for the selective extraction and enrichment of phosphopeptides from biological samples. First, magnetic graphene was prepared according to our previous method. Next, we made the Fe3O4/graphene/TiO2 composite precursor using tetrabutyl titanate. Fe3O4/graphene/TiO2 composites were obtained after solvothermal and calcination treatments. We used standard protein-digestion solutions and human liver samples to test the enrichment ability of the obtained Fe3O4/graphene/TiO2 composites. The experimental results demonstrate that Fe3O4/graphene/TiO2 composites have a good phosphopeptide enrichment ability. PMID:23883739

  12. Polymer Stabilized Fe3O4-Graphene as an Amphiphilic Drug Carrier for Thermo-Chemotherapy of Cancer.

    PubMed

    Swain, Akshaya Kumar; Pradhan, Lina; Bahadur, Dhirendra

    2015-04-22

    In light of the growing interest in the search for cheap and effective solutions for cancer treatment, we report a simple one pot synthesis of polymer stabilized iron oxide-graphene (PIG) that could be realized on a large scale. The structural (Fe3O4 particle size of ∼11 nm), functional (various oxygen containing moieties), and magnetic (moment of ∼43 emu/g) properties of PIG are explored using various characterization techniques for possible biomedical applications. PIG shows good colloidal stability and is biocompatible even at higher concentrations (2.5 mg/mL) by virtue of cross-linking polymers. The biocompatibility of the composite has been tested using HeLa cell lines by computing the percentage of the reactive oxygen species through the 2,7-dichlorofluorescein (DCF) intensity level. PIG has the ability to load and release both hydrophobic and hydrophilic drugs with a good loading efficiency and capacity. The dug loading efficiency of PIG is measured to be ∼87% and ∼91% for doxorubicin (DOX) and paclitaxel (PTXL), respectively. Under an AC magnetic field, superparamagnetic PIG (2.5 mg/mL) takes less than 16 min to reach the stable hyperthermia temperature, suggesting it as a good anticancer material. A time-dependent cellular uptake of doxorubicin-conjugated PIG has been studied to optimize the parameters for thermo-chemotherapy of cancer. The synergetic effect of both the drug and hyperthermia is observed in the killing of the cancerous cells, verified by computing the cell apoptotic population using a flow cytometer. However, it has been noticed that, even in the absence of chemotherapy, PIG shows good antiproliferative activity with thermotherapy alone. PMID:25821899

  13. Hierarchical graphene@Fe3O4 nanocluster@carbon@MnO2 nanosheet array composites: synthesis and microwave absorption performance.

    PubMed

    Wang, Lei; Huang, Ying; Li, Chao; Chen, Junjiao; Sun, Xu

    2015-02-28

    The fabrication of novel hierarchical graphene@Fe3O4 nanocluster@carbon@MnO2 nanosheet array composites has been successfully carried out for the first time. The fabrication process involves the deposition of Fe3O4 nanoclusters on graphene's surface using a simple in situ hydrothermal method, subsequent introduction of carbon on the surface of graphene@Fe3O4 nanoclusters by combining the hydrothermal reaction and thermal treatment process, and finally formation of the hierarchical composites via a simple in situ redox replacement reaction between potassium permanganate (KMnO4) and carbon on the surface of graphene@Fe3O4 nanoclusters. Moreover, the microwave absorption properties of both graphene@Fe3O4 nanoclusters and hierarchical graphene@Fe3O4 nanocluster@carbon@MnO2 nanosheet array composites were investigated between 2 and 18 GHz microwave frequency bands. The electromagnetic data demonstrate that graphene@Fe3O4 nanocluster@carbon@MnO2 nanosheet array hierarchical composites exhibit significantly enhanced microwave absorption properties compared with graphene@Fe3O4 nanoclusters, which probably originate from the unique hierarchical structure and larger surface area. PMID:25630384

  14. One-step fabricated Fe3O4@C core-shell composites for dye removal: Kinetics, equilibrium and thermodynamics

    NASA Astrophysics Data System (ADS)

    Qu, Lingling; Han, Tingting; Luo, Zhijun; Liu, Cancan; Mei, Yan; Zhu, Ting

    2015-03-01

    B-Fe3O4@C core-shell composites were synthesized via one-pot hydrothermal carbonization (HTC) process and used as an adsorbent for the removal of methylene blue (MB) from aqueous solution. By using sodium borate as the catalyst, the hydrothermal carbonization process of B-Fe3O4@C core-shell composites was optimized and a higher surface area was obtained. The adsorbent was characterized by XRD, Raman spectra, SEM, TEM and N2 adsorption/desorption isotherms. We studied the dye adsorption process at different conditions and analyzed the data by employing the Langmuir and Freundlich models, and the equilibrium data fitted well with both models. Kinetic analyses were conducted by using the Lagergren pseudo-first-order and pseudo-second-order model and the results showed that the adsorption process was more consistent with the pseudo-second-order kinetics. To better understand the dye adsorption process from the thermodynamics perspective, we also calculated ΔHο, ΔSο, ΔGο and Ea, the results suggesting that the MB adsorption process was physisorption endothermic process, and spontaneous at room temperature. The as-synthesized B-Fe3O4@C showing high magnetic sensitivity provides a facile and efficient way to recycle from aqueous solution.

  15. Study of AC Magnetic Properties and Core Losses of Fe/Fe3O4-epoxy Resin Soft Magnetic Composite

    NASA Astrophysics Data System (ADS)

    Laxminarayana, T. A.; Manna, Subhendu Kumar; Fernandes, B. G.; Venkataramani, N.

    Soft Magnetic Composites (SMC) were prepared by coating of nanocrystalline Fe3O4 particles, synthesized by co-precipitation method, on atomized iron powder of particle size less than 53 μm in size using epoxy resin as a binder between iron and Fe3O4. Fe3O4 was chosen, for its high electric resistivity and suitable magnetic properties, to keep the coating layer magnetic and seek improvement to the magnetic properties of SMC. SEM images and XRD patterns were recorded in order to investigate the coatings on the surface of iron powder. A toroid was prepared by cold compaction of coated iron powder at 1050 MPa and subsequently cured at 150˚C for 1 hr in argon atmosphere. For comparison of properties, a toroid of uncoated iron powder was also compacted at 1050 MPa and annealed at 600˚C for 2 hr in argon atmosphere. The coated iron powder composite has a resistivity of greater than 200 μΩm, measured by four probe method. A comparison of Magnetic Hysteresis loops and core losses using B-H Loop tracer in the frequency range 0 to 1500 Hz on the coated and uncoated iron powder is reported.

  16. Preparation and Characterization of Graphene/Fe3O4 Composites by Solvothermal Method.

    PubMed

    Zhou, Lin; Peng, Xiaoling; Wang, Xinqing; Jin, Dingfeng; Jin, Hongxiao; Ge, Hongliang

    2015-06-01

    In the present study, graphene/Fe3O4 nanocomposites were prepared by solvothermal method using graphite oxide (GO) and FeCl3 x 6H2O as starting materials and the products were characterized by X-ray Diffraction (XRD), Scanning Electronic Microscope (SEM) and Vibrating Sample Magnetometer (VSM). Effects of Fe ion concentration, temperature and time of solvothermal reaction on the magnetic properties, microstructures and morphologies of graphene/Fe3O4 nanocomposites were investigated. The results showed that with the raising of Fe ion, particle size of the products became bigger, and saturation magnetization of the products got higher. The saturation magnetization and particle size of the products can be enhanced by increasing the reaction time and temperature, but the change of saturation magnetization and particle size were not obvious after the time got 8 h and temperature was at 200 degrees C, which demonstrated that the products became stable under this condition. The morphologies, microstructures and properties of products can be controlled by adjusting synthesis conditions. PMID:26369052

  17. Synthesis for Magnetic Mesoporous Fe3O4-SiO2 Composites and Heterogeneous Fenton Degradation of Methyl Blue

    NASA Astrophysics Data System (ADS)

    Xie, Huanling; Zhang, Tengyun

    2014-12-01

    In this work, we presented a facile, one-step preparation for magnetic mesoporous Fe3O4-SiO2 composites under closely neutral conditions by an evaporation-induced self-assembly (EISA) and adding 1,3,5-TMB as co-solvent approach. The resulting samples were characterized by X-ray diffraction, N2 adsorption measurement, FT-IR and SEM. Magnetic mesoporous composites and H2O2 form heterogeneous Fenton in order to removal methylene blue as the dye wastewater model object. The catalysts showed high catalytic activity and stability in the decolorization of methlye blue.

  18. Controlling exchange bias in Fe3O4/FeO composite particles prepared by pulsed laser irradiation

    PubMed Central

    2011-01-01

    Spherical iron oxide nanocomposite particles composed of magnetite and wustite have been successfully synthesized using a novel method of pulsed laser irradiation in ethyl acetate. Both the size and the composition of nanocomposite particles are controlled by laser irradiation condition. Through tuning the laser fluence, the Fe3O4/FeO phase ratio can be precisely controlled, and the magnetic properties of final products can also be regulated. This work presents a successful example of the fabrication of ferro (ferri) (FM)/antiferromagnetic (AFM) systems with high chemical stability. The results show this novel simple method as widely extendable to various FM/AFM nanocomposite systems. PMID:21711758

  19. Competitive fluorescence assay for specific recognition of atrazine by magnetic molecularly imprinted polymer based on Fe3O4-chitosan.

    PubMed

    Liu, Guangyang; Li, Tengfei; Yang, Xin; She, Yongxin; Wang, Miao; Wang, Jing; Zhang, Min; Wang, Shanshan; Jin, Fen; Jin, Maojun; Shao, Hua; Jiang, Zejun; Yu, Hailong

    2016-02-10

    A novel fluorescence sensing strategy for determination of atrazine in tap water involving direct competition between atrazine and 5-(4,6-dichlorotriazinyl) aminofluorescein (5-DTAF), and which exploits magnetic molecularly imprinted polymer (MMIP), has been developed. The MMIP, based on Fe3O4-chitosan nanoparticles, was synthesized to recognize specific binding sites of atrazine. The recognition capability and selectivity of the MMIP for atrazine and other triazine herbicides was investigated. Under optimal conditions, the competitive reaction between 5-DTAF and atrazine was performed to permit quantitation. Fluorescence intensity changes at 515 nm was linearly related to the logarithm of the atrazine concentration for the range 2.32-185.4 μM. The detection limit for atrazine was 0.86μM (S/N=3) and recoveries were 77.6-115% in spiked tap water samples. PMID:26686107

  20. Core-shell superparamagnetic Fe3O4@β-CD composites for host-guest adsorption of polychlorinated biphenyls (PCBs).

    PubMed

    Wang, Manlin; Liu, Peng; Wang, Yu; Zhou, Dongmei; Ma, Chen; Zhang, Dongju; Zhan, Jinhua

    2015-06-01

    The effective recognition and enrichment of trace polychlorinated biphenyls (PCBs) in the environment are currently challenging issues due to human health concerns. In this paper, a surface absorptive layer coating superparamagnetic Fe3O4 nanoparticles for PCBs enrichment were prepared. This protocol involved the synthesis of Fe3O4 particles through a solvothermal reaction and the covering of a silica layer bonded β-cyclodextrin (β-CD) over Fe3O4 via a sol-gel process to construct core-shell Fe3O4@β-CD composites. β-CD was linked covalently to Fe3O4 nanoparticles to generate the binding sites, enhancing the stability of Fe3O4 nanoparticles in water. Meanwhile, superparamagnetic Fe3O4 core could be rapidly separated from matrix to simplify time-consuming washing extraction. The adsorption capacity of Fe3O4@β-CD composites to PCB28 and PCB52 in aqueous solutions was investigated. To estimate the theoretical binding site number of Fe3O4@β-CD, the obtained binding data were replotted according to Scatchard equation. The host-guest interaction between β-CD and PCBs were further examined with density functional theory (DFT) calculations. It provides theoretical evidence of β-CD as host molecule has a higher binding amount towards PCB-28 than PCB-52 on the basis of their optimized geometries and calculated complexation energies. The nanomaterial reported herein is an ideal candidate for various applications, including the recognition and removal of environmentally deleterious substances. PMID:25687400

  1. One-Pot Synthesis of Hydrophilic Superparamagnetic Fe3O4/Poly(methyl methacrylate-acrylic acid) Composite Nanoparticles with High Magnetization.

    PubMed

    Ma, Shaohua; Lan, Fang; Yang, Qi; Xie, Liqin; Wu, Yao; Gu, Zhongwei

    2015-01-01

    Uniform superparamagnetic Fe3O4/poly(methyl methacrylate-acrylic acid) (P(MMA-AA)) composite nanoparticles with high saturation magnetization and good hydrophilicity were successfully and directly synthesized via a facile one-pot miniemulsion polymerization approach. The mixture of the ferrofluids, MMA and AA monomers, surfactants and initiator was co-sonicated and emulsified to prepare stable miniemulsion for polymerization. The as-prepared products were characterized by SEM, TEM, FT-IR, XRD, TGA and VSM. The results of SEM indicated that the morphology of the Fe3O4/P(MMA-AA) composite nanoparticles all assumed near spherical geometry with diameters about 60 nm, 60 nm, and 100 nm respectively corresponding to the weight ratios of Fe3O4 to MMA and AA at 1:8, 1:4, and 1:2. The TEM images implied that the Fe3O4/P(MMA-AA) composite nanoparticles showed a perfect core-shell structure with a polymeric shell of about 2 nm thickness and a core encapsulating uniform and close packed Fe3O4 nanoparticles. TGA and VSM showed that the Fe3O4/P(MMA-AA) composite nanoparticles with a maximum saturation magnetization up to 45 emu g(-1) corresponding to the magnetite content of 78% exhibited superparamagntism. The hydrophilic modification and the high saturation magnetization impart a promising potential for biomedical applications to the as-synthesized composite nanoparticles. PMID:26328359

  2. Hybrid absorbers composed of Fe3O4 thin film and magnetic composite sheet and enhancement of conduction noise absorption on a microstrip line

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Soo

    2015-05-01

    In response to develop wide-band noise absorbers with an improved low-frequency performance, this study investigates hybrid absorbers that are composed of conductive Fe3O4 thin film and magnetic composite sheets. The Fe3O4 films prepared via reactive sputtering exhibit a typical value of electrical resistivity of ≃10-4 Ωm. Rubber composites with flaky Fe-Si-Al particles of a high permeability and high permittivity are used as the magnetic sheet functioning as an electromagnetic shield barrier. Microstrip lines with a characteristic impedance of 50 Ω are used to measure the noise absorbing properties. For the Fe3O4 film with a low surface resistance and covered by the magnetic sheet, approximately 80% power absorption can be obtained at 1 GHz, which is significantly higher than that of the original magnetic sheet or Fe3O4 film. The high power absorption of the hybrid absorber is attributed to the enhanced ohmic loss of the Fe3O4 film through increased electric field strength bounded by the upper magnetic composite sheet. The noise absorption is further enhanced through increasing the electrical conductivity of the film containing more conductive phase (Fe3O4 + Fe), which can be prepared in a reduced oxygen partial pressure during reactive sputtering.

  3. Growth mechanism of ZnO nanorod/Fe3O4 nanoparticle composites and their photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Wang, Wenda; Yu, Leiming; Yang, Hanjia; Hong, Kunquan; Qiao, Zhenfang; Wang, Hai

    2015-11-01

    ZnO nanorods/Fe3O4 nanocomposites as the recyclable photocatalyst were synthesized by a co-precipitation method, with microwave assistant by dropping alkaline solution with Fe3O4 nanoparticles into the aqueous of zinc salt. These Fe3O4 nanoparticles were the nucleated centers for the ZnO nanorods growth so that these nanorods ended with aggregated Fe3O4 nanoparticles. The growth processes and mechanism are explained as those insoluble zinc hydroxides prefer to nucleate on the surface of Fe3O4 nanoparticles (heterogeneous nucleation) rather than nucleated as isolated ZnO nanostructures (homogeneous nucleation). These nanocomposites have strong photocatalytic ability to reduce RhB and moderate magnetization, which make them being good recyclable photocatalysts.

  4. Co-assembly of CdTe and Fe3O4 with molecularly imprinted polymer for recognition and separation of endocrine disrupting chemicals

    NASA Astrophysics Data System (ADS)

    Chang, Limin; Chen, Shaona; Chu, Jia; Li, Xin

    2013-11-01

    In this study, we present a general protocol to fabricate imprinting matrix co-loaded with CdTe quantum dots and Fe3O4 nanoparticles for the recognition of endocrine disrupting chemicals (EDCs). The resultant composites were characterized by transmission electron microscopy, fluorescence spectroscopy, and energy dispersive spectroscopy. The materials have been demonstrated to be characterized with spherical shape with a saturation magnetization value of 1.7 emu g-1. Furthermore, the rebinding experiments show that the resultant materials have greater affinity and selectivity towards p-nitrophenol (model EDCs) over structurally related compounds. We believe that the effective method proposed in this work might provide a platform to prepare magnetic and fluorescent molecularly imprinted polymers for the recognition and separation of EDCs.

  5. In situ dispersion of non-aqueous Fe3O4 nanocolloids by microdroplet coalescence and their use in the preparation of magnetic composite particles.

    PubMed

    Du, Le; Wang, Yujun; Xu, Jianhong; Shen, Chun; Luo, Guangsheng

    2016-06-21

    Monodispersity and size uniformity are critical issues for nanoparticles, especially for the inorganic particles dispersed in organic carriers serving as the precursor of composites. Herein, for the first time, we have developed a method based on flow-induced droplet coalescence for in situ dispersion of surface-modified Fe3O4 nanoparticles to prepare Fe3O4/polystyrene (Fe3O4/PS) composite particles. A plate-type microchannel was constructed to initiate droplet coalescence for reducing the water-oil interfacial area and for dispersing Fe3O4 nanoparticles into the precursor suspensions. Under optimized conditions, the precursor suspensions could be composed of monodispersed Fe3O4 nanoparticles with an average size of approximately 12 nm. In this case, the saturation magnetization of the prepared superparamagnetic composites was as high as 4.012 emu g(-1) at a magnetite content of 5 wt%. The method is simple and has great potential to be tailored for the preparation of non-aqueous suspensions with uniform and monodispersed nanoparticles. PMID:27191775

  6. Fe3O4/PANI/P(MAA-co-NVP) multilayer composite microspheres with electric and magnetic features: assembly and characterization.

    PubMed

    Luo, Yan-Ling; Fan, Li-Hua; Gao, Gai-Ling; Chen, Ya-Shao; Shao, Xiao-Hua

    2009-11-01

    A core-shell multilayered composite microsphere with electric and magnetic features was designed and prepared on the basis of mutilayered fabrication. This kind of microspheres was obtained by introducing a rod-like conductive polyanilline (PANI) or its derivatives onto the surface of magnetic Fe3O4 nanoparticles with 4,4'-diphenylmethane diisocyanate as a anchor molecule. Subsequently, the Fe3O4/PANI or Fe3O4/aniline oligomers microspheres, as a secondary core, were covered with a cross-linked shell layer which was constructed by a dispersion polymerization process of methacrylic acid and vinyl pyrrolidone. The structure and morphologies were characterized by using a FTIR, XRD, UV-vis, SEM, TEM and TGA. The average diameter of Fe3O4 nanoparticles prepared is about 10.7 nm, and the PANI nanobars hold the size in the range of about 20.4-25.6 nm. The PANI nanobars are covalently assembled on the surface of Fe3O4 nanoparticles mainly in a mode of extended or horizontal arrangements through XRD and TEM results. The electromagnetic properties were examined based on different polymerization degrees and component ratios of PANI or its derivatives, showing characteristics of soft magnetic materials and controllable conductivity. The multilayer microspheres can be readily used to perform separation and magnetism guide, even electric and pH-modulated drug release in the light of swelling determination and a laser diffraction particle size analyzer, and are potentially of interest for drug targeting purpose. PMID:19908547

  7. Fe3O4/CuO/ZnO/Nano graphene platelets (Fe3O4/CuO/ZnO/NGP) composites prepared by sol-gel method with enhanced sonocatalytic activity for the removal of dye

    NASA Astrophysics Data System (ADS)

    Hendry, Tju; Taufik, Ardiansyah; Saleh, Rosari

    2016-04-01

    In this study, an attempt has been made to synthesize nanographene platelets coupled with Fe3O4/CuO/ZnO (Fe3O4/CuO/ZnO/NGP) with various ZnO loadings using a two step methods, sol-gel followed by hydrothermal method. Characterization was carried out by X-ray diffraction, energy-dispersive X-ray spectroscopy and vibrating sample magnetometer. The sonocatalytic performance was evaluated by degradation of methylene blue under ultrasonic irradiation.The Fe3O4/CuO/ZnO/NGP showed superior sonocatalytic activity than the Fe3O4/CuO/ZnO materials. They also showed high stability and can be easily separated from the reaction system for recycling process.

  8. Fabrication of Fe3O4@mSiO2 Core-Shell Composite Nanoparticles for Drug Delivery Applications

    NASA Astrophysics Data System (ADS)

    Uribe Madrid, Sergio I.; Pal, Umapada; Kang, Young Soo; Kim, Junghoon; Kwon, Hyungjin; Kim, Jungho

    2015-05-01

    We report the synthesis of Fe3O4@mSiO2 nanostructures of different meso-silica (mSiO2) shell thickness, their biocompatibility and behaviors for loading and release of a model drug ibuprofen. The composite nanostructures have superparamagnetic magnetite cores of 208 nm average size and meso-silica shells of 15 to 40 nm thickness. A modified Stöber method was used to grow the meso-silica shells over the hydrothermally grown monodispersed magnetite particles. The composite nanoparticles show very promising drug holding and releasing behaviors, which depend on the thickness of meso-silica shell. The biocompatibility of the meso-silica-coated and uncoated magnetite nanoparticles was tested through cytotoxicity assay on breast cancer (MCF-7), ovarian cancer (SKOV3), normal human lung fibroblasts MRC-5, and IMR-90 cells. The high drug holding capacity and reasonable biocompatibility of the nanostructures make them ideal agents for targeted drug delivery applications in human body.

  9. Synthesis, characterization, and application of Fe3O4/Ag magnetic composites for mercury removal from water

    NASA Astrophysics Data System (ADS)

    Elhouderi, Z. A.; Beesley, D. P.; Nguyen, T. T.; Lai, P.; Sheehan, K.; Trudel, S.; Prenner, E.; Cramb, D. T.; Anikovskiy, M.

    2016-04-01

    Engineered nanocomposites (NCs) have recently emerged as materials of great scientific and technological interest. In these materials, different components are combined to yield a nanoentity with desired properties not afforded by the constituent materials. Designing novel NCs and synthetic routes that enable controlling the size and functionalities remains an active area of research. Here, we present a two-step method of synthesizing Ag–Fe3O4 NCs with tunable sizes. Unlike previously reported structures, the prepared NCs do not have a familiar core–shell architecture. Instead, small Fe3O4 nanoparticles (NPs) are embedded in a larger silver matrix. The superparamagnetic Fe3O4 NPs endow the NC with magnetic properties, enabling easy separation from solution. The degree of the NC response to an external magnetic field can be controlled by varying the concentration of Fe3O4 NPs during the synthesis. The Ag matrix serves to protect the embedded Fe3O4 NPs from degradation and can be used for further functionalization of the NCs with different sulfhydryl containing linkers. To demonstrate utility, we show how decorating the outer layer of the Ag NC with diphenyl-4,4‧-dithiol transforms the NCs into a water purifying system capable of sequestering highly toxic Hg2+ ions from solution magnetically.

  10. A multifunctional mesoporous Fe3O4/SiO2/CdTe magnetic-fluorescent composite nanoprobe

    NASA Astrophysics Data System (ADS)

    Yin, Naiqiang; Wu, Ping; Liang, Guo; Cheng, Wenjing

    2016-03-01

    A multifunctional mesoporous, magnetic and fluorescent Fe3O4/SiO2/CdTe nanoprobe with well-defined core-shell nanostructures was prepared. This multifunctional nanoprobe was synthesized through a novel method mainly including two steps. The first step involved the controlled growth of mesoporous silica layer onto the surface of Fe3O4 nanoparticle using tetraethyl orthosilicate as silica source, cationic surfactant cetyltrimethylammonium bromide as template, and 1,3,5-triisopropylbenzene as pore swelling agents. The second step involved the layer-by-layer assembly of 3-aminopropyltrimethoxysilane and fluorescent CdTe quantum dots with the mesoporous Fe3O4/SiO2 nanoparticles. The well-designed nanoprobe exhibits strong excitonic photoluminescence and superparamagnetism at room temperature. In attention, the mesoporous silica layer of the nanoprobe with great loading capacity makes it a promising candidate as targeted drug delivery platform.

  11. Bio-Inspired Hierarchical Nanofibrous Fe3O4-TiO2-Carbon Composite as a High-Performance Anode Material for Lithium-Ion Batteries.

    PubMed

    Li, Shun; Wang, Mengya; Luo, Yan; Huang, Jianguo

    2016-07-13

    A bioinspired hierarchical nanofibrous Fe3O4-TiO2-carbon composite was fabricated by employing natural cellulose substance (e.g., filter paper) as both the scaffold and the carbon source and showed improved electrochemical performances when it is employed as an anode material for lithium-ion batteries. FeOOH nanoparticles were first grown uniformly onto the surface of the titania thin-layer precoated cellulose nanofibers, and thereafter, the as-prepared FeOOH-TiO2-cellulose composite was calcined and carbonized in argon atmosphere at 500 °C for 6 h to produce the Fe3O4-TiO2-carbon composite. The resultant composite possesses a hierarchical structure that was faithfully inherited from the initial cellulose substance, which was composed of titania-coated carbon fibers with corncob-like shaped Fe3O4 nanoparticles immobilized on the surfaces. The diameter of the composite nanofiber is ca. 100-200 nm, and the diameter of the Fe3O4 nanoparticle is about 30 nm, which is coated with an ultrathin carbon layer with a thickness about 3 nm. This composite displayed superior lithium-ion storage performance. It showed a first-cycle discharge capacity of 1340 mAh/g, delivering a stable reversible capacity of ca. 525 mAh/g after 100 charge-discharge cycles at a current density of 100 mA/g, and the efficiency is as high as ca. 95% of the theoretical value. This is much higher than those of the commercial Fe3O4 powder (160 mAh/g) and the Fe3O4-carbon counter material (310 mAh/g). It was demonstrated that the thin titania precoating layer (thickness ca. 3-5 nm) is necessary for the high content loading of the Fe3O4 nanoparticles onto the carbon nanofibers. Owing to the unique three-dimensional porous network structure of the carbon-fiber scaffold, together with the ultrathin outer carbon-coating layer, the composite showed significantly improved cycling stability and rate capability. PMID:27328774

  12. Monodisperse magnetite (Fe3O4) nanoparticles modified with water soluble polymers for the diagnosis of breast cancer by MRI method

    NASA Astrophysics Data System (ADS)

    Rezayan, Ali Hossein; Mosavi, Majid; Kheirjou, Somayyeh; Amoabediny, Ghasem; Ardestani, Mehdi Shafiee; Mohammadnejad, Javad

    2016-12-01

    In this study, magnetic nanoparticles (MNPs) were synthesized via co-precipitation method. To enhance the biocompatibility and colloidal stability of the synthesized nanoparticles, they were modified with carboxyl functionalized PEG via dopamine (DPA) linker. Both modified and unmodified Fe3O4 nanoparticles exhibited super paramagnetic behavior (particle size below 20 nm). The saturation magnetization (Ms) of PEGdiacid-modified Fe3O4 was 45 emu/g, which was less than the unmodified Fe3O4 nanoparticles (70 emu/g). This difference indicated that PEGdiacid polymer was immobilized on the surface of Fe3O4 nanoparticles successfully. To evaluate the efficiency of the resulting nanoparticles as contrast agents for magnetic resonance imaging (MRI), different concentration of MNPs and different value of echo time TE were investigated. The results showed that by increasing the concentration of the nanoparticles, transverse relaxation time (T2) decreased, which subsequently resulted in MR signal enhancement. T2-weighted MR images of the different concentration of MNPs in different value of echo time TE indicated that MR signal intensity increased with increase in TE value up to 66 and then remained constant. The cytotoxicity effect of the modified and unmodified nanoparticles was evaluated in three different concentrations (12, 60 and 312 mg l-1) on MDA-MB-231 cancer cells for 24 and 48 h. In both tested time (24 and 48 h) for all three samples, the modified nanoparticles had long life time than unmodified nanoparticles. Cellular uptake of modified MNPs was 80% and reduced to 9% by the unmodified MNPs.

  13. Thermal decomposition assisted synthesis and upconversion property of Fe3O4@YPO4:Tm/Yb hybrid nano-composite phosphor

    NASA Astrophysics Data System (ADS)

    Tiwari, S. P.; Kumar, K.; Rai, V. K.

    2015-06-01

    Hybrid nano-composite phosphor has been successfully synthesized through thermal decomposition method. The dual phase of samples assigned by XRD analysis shows the formation of nano-composite with crystallite size 20 nm and 12 nm for YPO4: Tm/Yb and Fe3O4@YPO4:Tm/Yb respectively. The FESEM images show the spherical shape and non agglomerated formation of nanoparticles. Three bands in upconversion emission mode were found in intense blue at 472 nm, red at 662 nm and NIR at 798 nm regions corresponding to1G4 → 3H6, 1G4 → 3F4 and 3H4 → 3H6 transition states respectively. The lifetime for1G4 → 3H6 level is found 1150 microsecond and 1400 microsecond for YPO4: Tm/Yb and Fe3O4@YPO4:Tm/Yb samples respectively.

  14. Facile One-pot Transformation of Iron Oxides from Fe2O3 Nanoparticles to Nanostructured Fe3O4@C Core-Shell Composites via Combustion Waves

    PubMed Central

    Shin, Jungho; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2016-01-01

    The development of a low-cost, fast, and large-scale process for the synthesis and manipulation of nanostructured metal oxides is essential for incorporating materials with diverse practical applications. Herein, we present a facile one-pot synthesis method using combustion waves that simultaneously achieves fast reduction and direct formation of carbon coating layers on metal oxide nanostructures. Hybrid composites of Fe2O3 nanoparticles and nitrocellulose on the cm scale were fabricated by a wet impregnation process. We demonstrated that self-propagating combustion waves along interfacial boundaries between the surface of the metal oxide and the chemical fuels enabled the release of oxygen from Fe2O3. This accelerated reaction directly transformed Fe2O3 into Fe3O4 nanostructures. The distinctive color change from reddish-brown Fe2O3 to dark-gray Fe3O4 confirmed the transition of oxidation states and the change in the fundamental properties of the material. Furthermore, it simultaneously formed carbon layers of 5–20 nm thickness coating the surfaces of the resulting Fe3O4 nanoparticles, which may aid in maintaining the nanostructures and improving the conductivity of the composites. This newly developed use of combustion waves in hybridized nanostructures may permit the precise manipulation of the chemical compositions of other metal oxide nanostructures, as well as the formation of organic/inorganic hybrid nanostructures. PMID:26902260

  15. Facile One-pot Transformation of Iron Oxides from Fe2O3 Nanoparticles to Nanostructured Fe3O4@C Core-Shell Composites via Combustion Waves.

    PubMed

    Shin, Jungho; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2016-01-01

    The development of a low-cost, fast, and large-scale process for the synthesis and manipulation of nanostructured metal oxides is essential for incorporating materials with diverse practical applications. Herein, we present a facile one-pot synthesis method using combustion waves that simultaneously achieves fast reduction and direct formation of carbon coating layers on metal oxide nanostructures. Hybrid composites of Fe2O3 nanoparticles and nitrocellulose on the cm scale were fabricated by a wet impregnation process. We demonstrated that self-propagating combustion waves along interfacial boundaries between the surface of the metal oxide and the chemical fuels enabled the release of oxygen from Fe2O3. This accelerated reaction directly transformed Fe2O3 into Fe3O4 nanostructures. The distinctive color change from reddish-brown Fe2O3 to dark-gray Fe3O4 confirmed the transition of oxidation states and the change in the fundamental properties of the material. Furthermore, it simultaneously formed carbon layers of 5-20 nm thickness coating the surfaces of the resulting Fe3O4 nanoparticles, which may aid in maintaining the nanostructures and improving the conductivity of the composites. This newly developed use of combustion waves in hybridized nanostructures may permit the precise manipulation of the chemical compositions of other metal oxide nanostructures, as well as the formation of organic/inorganic hybrid nanostructures. PMID:26902260

  16. Facile One-pot Transformation of Iron Oxides from Fe2O3 Nanoparticles to Nanostructured Fe3O4@C Core-Shell Composites via Combustion Waves

    NASA Astrophysics Data System (ADS)

    Shin, Jungho; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2016-02-01

    The development of a low-cost, fast, and large-scale process for the synthesis and manipulation of nanostructured metal oxides is essential for incorporating materials with diverse practical applications. Herein, we present a facile one-pot synthesis method using combustion waves that simultaneously achieves fast reduction and direct formation of carbon coating layers on metal oxide nanostructures. Hybrid composites of Fe2O3 nanoparticles and nitrocellulose on the cm scale were fabricated by a wet impregnation process. We demonstrated that self-propagating combustion waves along interfacial boundaries between the surface of the metal oxide and the chemical fuels enabled the release of oxygen from Fe2O3. This accelerated reaction directly transformed Fe2O3 into Fe3O4 nanostructures. The distinctive color change from reddish-brown Fe2O3 to dark-gray Fe3O4 confirmed the transition of oxidation states and the change in the fundamental properties of the material. Furthermore, it simultaneously formed carbon layers of 5-20 nm thickness coating the surfaces of the resulting Fe3O4 nanoparticles, which may aid in maintaining the nanostructures and improving the conductivity of the composites. This newly developed use of combustion waves in hybridized nanostructures may permit the precise manipulation of the chemical compositions of other metal oxide nanostructures, as well as the formation of organic/inorganic hybrid nanostructures.

  17. Magnetic Fe3O4-graphene composites as targeted drug nanocarriers for pH-activated release

    NASA Astrophysics Data System (ADS)

    Fan, Xiujuan; Jiao, Guozheng; Zhao, Wei; Jin, Pengfei; Li, Xin

    2013-01-01

    A novel nanocarrier of magnetic Fe3O4-graphene nanocomposites (MGNs) was proposed as an effective drug delivery system for cancer treatment. The nanocarrier was synthesized by covalently attaching modified Fe3O4 nanoparticles onto water-soluble graphene sheets via the formation of an amide bond with the aid of 1-ethyl-3-(3-dimethyaminopropyl) carbodiimide. The obtained MGNs exhibited excellent dispersibility and stability in aqueous solution and they also exhibited superparamagnetic properties with a saturation magnetization of 23.096 emu g-1. An efficient loading of 5-fluorouracil (5-FU) on MGNs as high as 0.35 mg mg-1 was obtained. Furthermore, the in vitro drug release of 5-FU was examined in pH 6.9 and pH 4.0 buffers at 37 °C, and showed strong pH dependence. Transmission electron microscope observations revealed that MGNs can be internalized efficiently by HepG2 cells. More importantly, the cytotoxicity evaluation shows that the resulting MGNs exhibit excellent biocompatibility. The as-prepared nanocarrier system combined the advantages of the superparamagnetic iron oxide nanoparticles and water-soluble graphene sheets, which will find many potential applications in biomedicine and biomaterials.

  18. Preparation and characterization of EDTAD-modified magnetic-Fe3O4 chitosan composite: application of comparative adsorption of dye wastewater with magnetic chitosan.

    PubMed

    Yang, Hongyu; Li, Yunchun; Ho, Steven Sai Hang; Tian, Xiumei; Xia, Yunxue; Shen, Yaou; Zhao, Maojun; Pan, Guangtang

    2013-01-01

    Ethylenediaminetetraacetic dianhydride (EDTAD)-modified magnetic-Fe3O4 chitosan (EMC), prepared using the cross-link agent glutaraldehyde and chemicals Fe3O4, chitosan, and EDTAD, was used to compare the adsorption of methylene blue (MB) with magnetic chitosan (MC). The composite structure was confirmed by multiple characterization techniques, including scanning electron microscopy (SEM), X-ray powder diffraction, Fourier transform infrared spectroscopy (FTIR), and potentiometric titration methods. The characterization results suggest that Fe3O4 particles successfully bound on the surface of chitosan, and the EDTAD thoroughly modified the MC. Furthermore, EMC had more amino, carboxyl, and hydroxy groups than typical MC. Adsorption conditions, such as pH values, initial concentrations of MB, reaction temperature, and contact time were systematically examined. In comparison, the maximum adsorption capacity of EMC was approximately twice as much as that of MC. The recovery efficiency for EMC was >80% using 0.1 M HCl as an eluent solution. Therefore, the results reported herein indicate that EMC is very attractive and imply a practical application for dye wastewater treatment. PMID:23823557

  19. Magnetic field dependant backscattering of light in water based ferrofluid containing polymer covered Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Brojabasi, Surajit; Philip, John

    2013-02-01

    We probe the effect of applied magnetic field on the backscattering light intensity from a magnetic nanofluid consisting of poly-acrylic acid coated Fe3O4 nanoparticles of diameter, ˜15 nm dispersed in water. We observe a continuous evolution of backscattered speckle pattern as a function of magnetic field strength. The speckle contrast is found to increase linearly with external magnetic field possibly due to the evolution from highly dynamic to static scatterers in the dispersion. The backscattered light intensity is found to diminish with external magnetic field, which is attributed to the delay of light propagation for the formation of standing waves within the scatterer due to the resonances in backscattered efficiency and forward-backward anisotropy factor. Interestingly, the backscattered light intensity completely recovers when magnetic field is switched off. We discuss the possible reasons for the angular variation of backscattered light intensity. Our results suggest that the field dependent light propagation through the magnetic nanofluid may find interesting applications in tunable light controlling devices.

  20. Studies on Properties of Rice Straw/Polymer Nanocomposites Based on Polycaprolactone and Fe3O4 Nanoparticles and Evaluation of Antibacterial Activity

    PubMed Central

    Khandanlou, Roshanak; Ahmad, Mansor B.; Shameli, Kamyar; Saki, Elnaz; Kalantari, Katayoon

    2014-01-01

    Modified rice straw/Fe3O4/polycaprolactone nanocomposites (ORS/Fe3O4/PCL-NCs) have been prepared for the first time using a solution casting method. The RS/Fe3O4-NCs were modified with octadecylamine (ODA) as an organic modifier. The prepared NCs were characterized by using X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The XRD results showed that as the intensity of the peaks decreased with the increase of ORS/Fe3O4-NCs content in comparison with PCL peaks, the Fe3O4-NPs peaks increased from 1.0 to 60.0 wt. %. The TEM and SEM results showed a good dispersion of ORS/Fe3O4-NCs in the PCL matrix and the spherical shape of the NPs. The TGA analysis indicated thermal stability of ORS/Fe3O4-NCs increased after incorporation with PCL but the thermal stability of ORS/Fe3O4/PCL-NCs decreased with the increase of ORS/Fe3O4-NCs content. Tensile strength was improved with the addition of 5.0 wt. % of ORS/Fe3O4-NCs. The antibacterial activities of the ORS/Fe3O4/PCL-NC films were examined against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) by diffusion method using nutrient agar. The results indicated that ORS/Fe3O4/PCL-NC films possessed a strong antibacterial activity with the increase in the percentage of ORS/Fe3O4-NCs in the PCL. PMID:25318051

  1. High Energy Density Asymmetric Supercapacitor Based on NiOOH/Ni3S2/3D Graphene and Fe3O4/Graphene Composite Electrodes

    PubMed Central

    Lin, Tsung-Wu; Dai, Chao-Shuan; Hung, Kuan-Chung

    2014-01-01

    The application of the composite of Ni3S2 nanoparticles and 3D graphene as a novel cathode material for supercapacitors is systematically investigated in this study. It is found that the electrode capacitance increases by up to 111% after the composite electrode is activated by the consecutive cyclic voltammetry scanning in 1 M KOH. Due to the synergistic effect, the capacitance and the diffusion coefficient of electrolyte ions of the activated composite electrode are ca. 3.7 and 6.5 times higher than those of the Ni3S2 electrode, respectively. Furthermore, the activated composite electrode exhibits an ultrahigh specific capacitance of 3296 F/g and great cycling stability at a current density of 16 A/g. To obtain the reasonable matching of cathode/anode electrodes, the composite of Fe3O4 nanoparticles and chemically reduced graphene oxide (Fe3O4/rGO) is synthesized as the anode material. The Fe3O4/rGO electrode exhibits the specific capacitance of 661 F/g at 1 A/g and excellent rate capability. More importantly, an asymmetric supercapacitor fabricated by two different composite electrodes can be operated reversibly between 0 and 1.6 V and obtain a high specific capacitance of 233 F/g at 5 mV/s, which delivers a maximum energy density of 82.5 Wh/kg at a power density of 930 W/kg. PMID:25449978

  2. Electrochemical detection of arsenic(III) completely free from noble metal: Fe3O4 microspheres-room temperature ionic liquid composite showing better performance than gold.

    PubMed

    Gao, Chao; Yu, Xin-Yao; Xiong, Shi-Quan; Liu, Jin-Huai; Huang, Xing-Jiu

    2013-03-01

    In recent decades, electrochemical detection of arsenic(III) has been undergoing revolutionary developments with higher sensitivity and lower detection limit. Despite great success, electrochemical detection of As(III) still depends heavily on noble metals (predominantly Au) in a strong acid condition, thus increasing the cost and hampering the widespread application. Here, we report a disposable platform completely free from noble metals for electrochemical detection of As(III) in drinking water under nearly neutral condition by square wave anodic stripping voltammetry. By combining the high adsorptivity of Fe3O4 microspheres toward As(III) and the advantages of room temperature ionic liquid (RTIL), the Fe3O4-RTIL composite modified screen-printed carbon electrode (SPCE) showed even better electrochemical performance than commonly used noble metals. Several ionic liquids with different viscosities and surface tensions were found to have a different effect on the voltammetric behavior toward As(III). Under the optimized conditions, the Fe3O4-RTIL composites offered direct detection of As(III) within the desirable range (10 ppb) in drinking water as specified by the World Health Organization (WHO), with a detection limit (3σ method) of 8 × 10(-4) ppb. The obtained sensitivity was 4.91 μA ppb(-1), which is the highest as far as we know. In addition, a possible mechanism for As(III) preconcentration based on adsorption has been proposed and supported by designed experiments. Finally, this platform was successfully applied to analyzing a real sample collected from Inner Mongolia, China. PMID:23374085

  3. Enhanced performance of polymer solar cells using PEDOT:PSS doped with Fe3O4 magnetic nanoparticles aligned by an external magnetostatic field as an anode buffer layer.

    PubMed

    Wang, Kai; Yi, Chao; Hu, Xiaowen; Liu, Chang; Sun, Yan; Hou, Jianhui; Li, Yongfang; Zheng, Jie; Chuang, Steven; Karim, Alamgir; Gong, Xiong

    2014-08-13

    Low efficiency and poor stability are two major obstacles limiting the manufacturing of renewable and cost-effective polymer solar cell (PSCs). To address these problems, solution-processed poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) doped with Fe3O4 magnetic nanoparticles ((PEDOT:PSS):Fe3O4), and above (PEDOT:PSS):Fe3O4 thin film aligned by an external magnetostatic field ([(PEDOT:PSS):Fe3O4] W/H) were used as the anode buffer layer for PSCs, respectively. As compared with PSCs with PEDOT:PSS as an anode buffer layer, 38.5% enhanced efficiency and twice improved stability are observed from PSCs incorporated with [(PEDOT:PSS):Fe3O4] W/H anode buffer layer. It was found that enhanced efficiency and improved stability resulted from a combination of reduced acidity of PEDOT:PSS and enhanced electrical conductivity that originated from generated counterions and the paramagnetism of Fe3O4 magnetic nanoparticles by an external magnetostatic field. PMID:24980462

  4. Adsorption of drinking water fluoride on a micron-sized magnetic Fe3O4@Fe-Ti composite adsorbent

    NASA Astrophysics Data System (ADS)

    Zhang, Chang; Li, Yingzhen; Wang, Ting-Jie; Jiang, Yanping; Wang, Haifeng

    2016-02-01

    A micron-sized magnetic adsorbent (MMA) for fluoride removal from drinking water was prepared by spray drying and subsequent calcination of a magnetic Fe3O4@Fe-Ti core-shell nanoparticle slurry. The MMA granules had high mechanical strength and stability against water scouring, can be easily separated from the water by a magnet, and had a high selectivity for fluoride versus common co-existing ions and high fluoride removal efficiency in a wide range of initial pH of 3-11. Abundant hydroxyl groups on the MMA surface acted as the active sites for fluoride adsorption, which resulted in a high affinity of the MMA for fluoride. The pH in the adsorption process affected the adsorption significantly. At neutral initial pH, the adsorption isotherm was well fitted with the Langmuir model, and the maximum adsorption capacity reached a high value of 41.8 mg/g. At a constant pH of 3, multilayer adsorption of fluoride occurred due to the abundant positive surface charges on the MMA, and the adsorption isotherm was well fitted with the Freundlich model. The MMA had a fast adsorption rate, and adsorption equilibrium was achieved within 2 min. The adsorption kinetics followed a quasi-second order model. The regeneration of the MMA was easy and fast, and can be completed within 2 min. After 10 recycles, the fluoride removal efficiency of the MMA still remained high. These properties showed that the MMA is a promising adsorbent for fluoride removal.

  5. Enzymatic interesterification of soybean oil and methyl stearate blends using lipase immobilized on magnetic Fe3O4/SBA-15 composites as a biocatalyst.

    PubMed

    Zang, Xuezhen; Xie, Wenlei

    2014-01-01

    The magnetic Fe3O4/SBA-15 composites were prepared, and treated with 3-aminopropyltriethoxysilane as a carrier material for enzyme immobilization. The immobilization of Candida rugosa lipase onto the amino-functionalized Fe3O4/SBA-15 composite was investigated by using glutaraldehyde as a coupling reagent. The immobilized lipase was then employed as a biocatalyst for the interesterification of soybean oil and methyl stearate in a laboratory-scale operation at 45°C. Various techniques, such as Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), and vibrating sample magnetometry (VSM), were used for the characterization of the immobilized lipase composite. The immobilized lipase behaved superparamagnetic and showed excellent response at applied magnetic field. The obtained results showed that the immobilized lipase could efficiently catalyze the interesterification reaction. Moreover, the interesterification reaction parameters, such as reaction temperature, substrate ratio and reaction time were investigated regarding the stearoyl incorporation into the triacylglycerols. Further, the immobilized lipase proved to be easily separated from the reaction mixture by applying an external magnetic field and to be stable in the repeated use for four cycles. PMID:25213444

  6. Magnetically separable mesoporous Fe3O4/silica catalysts with very low Fe3O4 content

    NASA Astrophysics Data System (ADS)

    Grau-Atienza, A.; Serrano, E.; Linares, N.; Svedlindh, P.; Seisenbaeva, G.; García-Martínez, J.

    2016-05-01

    Two magnetically separable Fe3O4/SiO2 (aerogel and MSU-X) composites with very low Fe3O4 content (<1 wt%) have been successfully prepared at room temperature by co-condensation of MPTES-functionalized Fe3O4 nanoparticles (NPs) with a silicon alkoxide. This procedure yields a homogeneous incorporation of the Fe3O4 NPs on silica supports, leading to magnetic composites that can be easily recovered using an external magnetic field, despite their very low Fe3O4 NPs content (ca. 1 wt%). These novel hybrid Fe3O4/SiO2 materials have been tested for the oxidation reaction of 3,3‧,5,5‧-tetramethylbenzidine (TMB) with hydrogen peroxide showing an enhancement of the stability of the NPs in the Fe3O4/silica aerogel as compared to the Fe3O4 NPs alone, even after five catalytic cycles, no leaching or agglomeration of the Fe3O4/SiO2 systems.

  7. Synergistic Ternary Composite (Carbon/Fe3 O4 @Graphene) with Hollow Microspherical and Robust Structure for Li-Ion Storage.

    PubMed

    Li, Xingxing; Zheng, Xueying; Shao, Jie; Gao, Tian; Shi, Qiang; Qu, Qunting

    2016-01-01

    The electrode materials with hollow structure and/or graphene coating are expected to exhibit outstanding electrochemical performances in energy-storage systems. 2D graphene-wrapped hollow C/Fe3 O4 microspheres are rationally designed and fabricated by a novel facile and scalable strategy. The core@double-shell structure SPS@FeOOH@GO (SPS: sulfonated polystyrene, GO: graphene oxide) microspheres are first prepared through a simple one-pot approach and then transformed into C/Fe3 O4 @G (G: graphene) after calcination at 500 °C in Ar. During calcination, the Kirkendall effect resulting from the diffusion/reaction of SPS-derived carbon and FeOOH leads to the formation of hollow structure carbon with Fe3 O4 nanoparticles embedded in it. In the rationally constructed architecture of C/Fe3 O4 @G, the strongly coupled C/Fe3 O4 hollow microspheres are further anchored onto 2D graphene networks, achieving a strong synergetic effect between carbon, Fe3 O4 , and graphene. As an anode material of Li-ion batteries (LIBs), C/Fe3 O4 @G manifests a high reversible capacity, excellent rate behavior, and outstanding long-term cycling performance (1208 mAh g(-1) after 200 cycles at 100 mA g(-1) ). PMID:26616668

  8. Manufacturing of Aluminum Matrix Composites Reinforced with Iron Oxide (Fe3O4) Nanoparticles: Microstructural and Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Bayraktar, Emin; Ayari, Fayza; Tan, Ming Jen; Tosun-Bayraktar, Ayse; Katundi, Dhurata

    2014-04-01

    The purpose of this paper is to demonstrate the low-cost manufacturing of aluminum matrix composites reinforced with nano iron oxide as light and efficient materials for engineering applications. It is very desirable to use reinforced aluminum matrix composites in structural applications (automotive, aeronautical, etc.) because of their outstanding stiffness-to-weight and strength-to-weight ratios. In modern industry, it is increasingly important to develop new composites as alternative materials to fabricate multifunctional pieces. Detailed information is presented on the manufacturing process of this composite, and a preliminary study was performed on the cryogenic-cycling behavior to evaluate the interface between the matrix and the reinforcement. Microindentation tests were carried out to evaluate the micromechanical properties of these materials; a simple and practical finite element model is proposed to predict certain parameters related to the composition of the composite.

  9. A Study of Fe3O4 Magnetic Nanoparticle RF Heating in Gellan Gum Polymer Under Various Experimental Conditions for Potential Application in Drug Delivery

    NASA Astrophysics Data System (ADS)

    Marcus, Gabriel E.

    Magnetic nanoparticles (MNPs) have found use in a wide variety of biomedical applications including hyperthermia, imaging and drug delivery. Certain physical properties, such as the ability to generate heat in response to an alternating magnetic field, make these structures ideal for such purposes. This study's objective was to elucidate the mechanisms primarily responsible for RF MNP heating and determine how such processes affect polymer solutions that might be useful in drug delivery. 15-20 nm magnetite (Fe3O4) nanoparticles at 0.2% and 0.5% concentrations were heated with RF fields of different strengths (200 Oe, 400 Oe and 600 Oe) in water and in 0.5% gellan gum solution. Mixing and fan cooling were used in an attempt to improve accuracy of data collection. Specific absorption rate (SAR) values were determined experimentally for each combination of solvent, concentration and field strength. Theoretical calculation of SAR was performed using a model based on linear response theory. Mixing yielded greater precision in experimental determination of SAR while the effects of cooling on this parameter were negligible. Solutions with gellan gum displayed smoother heating over time but no significant changes in SAR values. This was attributed to low polymer concentration and lack of structural phase transition. The LRT model was found to be adequate for calculating SAR at low polymer concentration and was useful in identifying Neel relaxation as the dominant heating process. Heating trials with MNPs in 2% agar confirmed Neel relaxation to be primarily responsible for heat generation in the particles studied.

  10. Superparamagnetic Fe3 O4 @SiO2 core-shell composite nanoparticles for the mixed hemimicelle solid-phase extraction of benzodiazepines from hair and wastewater samples before high-performance liquid chromatography analysis.

    PubMed

    Esmaeili-Shahri, Effat; Es'haghi, Zarrin

    2015-12-01

    Magnetic Fe3 O4 /SiO2 composite core-shell nanoparticles were synthesized, characterized, and applied for the surfactant-assisted solid-phase extraction of five benzodiazepines diazepam, oxazepam, clonazepam, alprazolam, and midazolam, from human hair and wastewater samples before high-performance liquid chromatography with diode array detection. The nanocomposite was synthesized in two steps. First, Fe3 O4 nanoparticles were prepared by the chemical co-precipitation method of Fe(III) and Fe(II) as reaction substrates and NH3 /H2 O as precipitant. Second, the surface of Fe3 O4 nanoparticles was modified with shell silica by Stober method using tetraethylorthosilicate. The Fe3 O4 /SiO2 composite were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. To enhance their adsorptive tendency toward benzodiazepines, cetyltrimethylammonium bromide was added, which was adsorbed on the surface of the Fe3 O4 /SiO2 nanoparticles and formed mixed hemimicelles. The main parameters affecting the efficiency of the method were thoroughly investigated. Under optimum conditions, the calibration curves were linear in the range of 0.10-15 μgmL(-1) . The relative standard deviations ranged from 2.73 to 7.07%. The correlation coefficients varied from 0.9930 to 0.9996. PMID:26412451

  11. A Fe/Fe3O4/N-carbon composite with hierarchical porous structure and in situ formed N-doped graphene-like layers for high-performance lithium ion batteries.

    PubMed

    Li, Yao; Meng, Qing; Zhu, Shen-min; Sun, Zeng-hui; Yang, Hao; Chen, Zhi-xin; Zhu, Cheng-ling; Guo, Zai-ping; Zhang, Di

    2015-03-14

    A Fe/Fe3O4/N-carbon composite consisting of a porous carbon matrix containing a highly conductive N-doped graphene-like network and Fe/Fe3O4 nanoparticles was prepared. The porous carbon has a hierarchical structure which is inherited from rice husk and the N-doped graphene-like network formed in situ. When used as an anode material for lithium batteries, the composite delivered a reversible capacity of approximately 610 mA h g(-1) at a current density of 200 mA g(-1) even after 100 cycles, due to the synergism between the unique hierarchical porous structures, highly electrically conductive N-doped graphene-like networks and nanosized particles of Fe/Fe3O4. This work provides a simple approach to prepare N-doped porous carbon activated nanoparticle composites which could be used to improve the electrochemical performance of lithium ion batteries. PMID:25655996

  12. Variable blocking temperature of a porous silicon/Fe3O4 composite due to different interactions of the magnetic nanoparticles.

    PubMed

    Rumpf, Klemens; Granitzer, Petra; Morales, Puerto M; Poelt, Peter; Reissner, Michael

    2012-01-01

    In the frame of this work, the aim was to create a superparamagnetic nanocomposite system with a maximized magnetic moment when magnetized by an external field and a blocking temperature far below room temperature. For this purpose, iron oxide nanoparticles of 3.8-, 5- and 8-nm size have been infiltrated into the pores of porous silicon. To fabricate tailored magnetic properties of the system, the particle size and the magnetic interactions among the particles play a crucial role. Different concentrations of the particles dispersed in hexane have been used for the infiltration to vary the blocking temperature TB, which indicates the transition between the superparamagnetic behavior and blocked state. TB is not only dependent on the particle size but also on the magnetic interactions between them, which can be varied by the particle-particle distance. Thus, a modification of the pore loading on the one hand and of the porous silicon morphology on the other hand results in a composite material with a desired blocking temperature. Because both materials, the mesoporous silicon matrices as well as the Fe3O4 nanoparticles, offer low toxicity, the system is a promising candidate for biomedical applications. PMID:22873748

  13. Immobilization of a novel cold active esterase onto Fe3O4∼cellulose nano-composite enhances catalytic properties.

    PubMed

    Rahman, Mohammad Asadur; Culsum, Umma; Kumar, Ashok; Gao, Haofeng; Hu, Nan

    2016-06-01

    A novel esterase, EstH was cloned, purified and characterized from the marine bacterium Zunongwangia sp. The purified EstH showed optimum activity at 30°C and pH 8.5 with ∼50% of original activity at 0°C. EstH was stable in high salt conditions (0-4.5M NaCl). To improve the characteristics and explore the possibilities for application, a new immobilization matrix, Fe3O4∼cellulose nano-composite, was prepared and was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Interestingly the optimal temperature of immobilized EstH elevated to 35°C. Compared to its free form, immobilized EstH showed better temperature stability (48.5% compared to 22.40% at 50°C after 30min), prolonged half-life (32h compared to 18h), higher storage stability (∼71% activity compared to ∼40% after 50days of storage), improved pH tolerance (∼73% activity at pH 4 and 10), and, more importantly, reusability (∼50% activity after 8 repetitive cycles of usage). Enzyme kinetics showed an increase in the Vmax (from 35.76 to 51.14μM/min) and Kcat (from 365s(-1) to 520s(-1)) after immobilization. The superior catalytic properties of immobilized EstH suggest its great potential in biotechnology and industrial processes. PMID:26976070

  14. Synthesis and electromagnetic, microwave absorbing properties of core-shell Fe3O4-poly(3, 4-ethylenedioxythiophene) microspheres.

    PubMed

    Zhou, Wencai; Hu, Xiujie; Bai, Xiaoxia; Zhou, Shuyun; Sun, Chenghua; Yan, Jun; Chen, Ping

    2011-10-01

    Highly regulated core-shell Fe(3)O(4)-poly(3, 4-ethylenedioxythiophene) (PEDOT) microspheres were successfully synthesized by a two-step method in the presence of polyvinyl alcohol (PVA) and p-toluenesulfonic acid (p-TSA). And their morphology, microstructure, electromagnetic and microwave absorbing properties were subsequently characterized. By simply adjusting the molar ratio of 3, 4-ethylenedioxythiophene (EDOT) to Fe(3)O(4) (represented by (EDOT)/(Fe(3)O(4))), the thickness of the polymer shell can be tuned from tens to hundreds of nanometers. Moreover, it was found that the composite exhibited excellent microwave absorbing property with a minimum reflection loss (RL) of about -30 dB at 9.5 GHz with a (EDOT)/(Fe(3)O(4)) ratio of 20. PMID:21913665

  15. Poly(acrylic acid)-modified Fe3O4 microspheres for magnetic-targeted and pH-triggered anticancer drug delivery.

    PubMed

    Kang, Xiao-Jiao; Dai, Yun-Lu; Ma, Ping-An; Yang, Dong-Mei; Li, Chun-Xia; Hou, Zhi-Yao; Cheng, Zi-Yong; Lin, Jun

    2012-12-01

    Monodisperse poly(acrylic acid)-modified Fe(3)O(4) (PAA@Fe(3)O(4)) hybrid microspheres with dual responses (magnetic field and pH) were successfully fabricated. The PAA polymer was encapsulated into the inner cavity of Fe(3)O(4) hollow spheres by a vacuum-casting route and photo-initiated polymerization. TEM images show that the samples consist of monodisperse porous spheres with a diameter around 200 nm. The Fe(3)O(4) spheres, after modification with the PAA polymer, still possess enough space to hold guest molecules. We selected doxorubicin (DOX) as a model drug to investigate the drug loading and release behavior of as-prepared composites. The release of DOX molecules was strongly dependent on the pH value due to the unique property of PAA. The HeLa cell-uptake process of DOX-loaded PAA@Fe(3)O(4) was observed by confocal laser scanning microscopy (CLSM). After being incubated with HeLa cells under magnet magnetically guided conditions, the cytotoxtic effects of DOX-loaded PAA@Fe(3)O(4) increased. These results indicate that pH-responsive magnetic PAA@Fe(3)O(4) spheres have the potential to be used as anticancer drug carriers. PMID:23080514

  16. Biocompatible polyurethane/thiacalix[4]arenes functionalized Fe3O4 magnetic nanocomposites: Synthesis and properties.

    PubMed

    Mohammadi, Abbas; Barikani, Mehdi; Lakouraj, Moslem Mansour

    2016-09-01

    In this study, a series of magnetic polyurethane/Fe3O4 elastomer nanocomposites were prepared by covalently embedding novel thiacalix[4]arenes (TC4As) functionalized Fe3O4 nanoparticles (TC4As-Fe3O4) which contain macrocycles with reactive hydroxyl groups. Surface functionalization of Fe3O4 nanoparticles with TC4As macrocycles as unique reactive surface modifier not only gives specific characteristics to Fe3O4 nanoparticles but also improves the interphase interaction between nanoparticles and the polyurethane matrices through covalent attachment of polymer chains to nanoparticle surfaces. The novel synthesized TC4As-Fe3O4 nanoparticles were characterized by FTIR, XRD, TGA, VSM and SEM analysis. Furthermore, the effect of functionalization of Fe3O4 nanoparticles on the various properties of resulting nanocomposites was studied by XRD, TGA, DMTA, SEM, and a universal tensile tester. It was found that the functionalization of nanoparticles with TC4As affords better mechanical and thermal properties to polyurethane nanocomposites in comparison with unmodified nanoparticles. The SEM analysis showed finer dispersion of TC4As-Fe3O4 nanoparticles than unmodified Fe3O4 nanoparticles within the polyurethane matrices, which arising from formation of covalent bonding between TC4As functionalized Fe3O4 nanoparticles and polyurethane matrices. Moreover, the investigation of in vitro biocompatibility of novel nanocomposites showed that these samples are excellent candidate for biomedical use. PMID:27207044

  17. Use of hydroxypropyl-β-cyclodextrin/polyethylene glycol 400, modified Fe3O4 nanoparticles for congo red removal.

    PubMed

    Yu, Lan; Xue, Weihua; Cui, Lei; Xing, Wen; Cao, Xinli; Li, Hongyu

    2014-03-01

    Fe3O4 nanoparticles were modified with Hydroxypropyl-β-cyclodextrin (HP-β-CD) and Polyethylene glycol 400 (PEG400) by a facile one-pot homogeneous precipitation method, and were used as a novel nano-adsorbent for the removal of congo red (CR) from aqueous solutions. The polymer-modified composites were characterized by FTIR, TEM, TGA, XRD and VSM, and showed excellent adsorption efficiency for CR. The value of the maximum adsorption capacity calculated according to the Langmuir isotherm model were 1.895g/g, which are much high and about 19 times that of Fe3O4 nanoparticles. Desorption study further indicates the good regeneration ability of the nanocomposites. The results suggest that the HP-β-CD/PEG400-modified Fe3O4 nanoparticles is a promising adsorbent for CR removal from aqueous solutions, and it is easily recycled owing to its large specific surface area and unique magnetic responsiveness. PMID:24333392

  18. Combined tween 20-stabilized gold nanoparticles and reduced graphite oxide-Fe3O4 nanoparticle composites for rapid and efficient removal of mercury species from a complex matrix.

    PubMed

    Shih, Ya-Chen; Ke, Chen-Yi; Yu, Cheng-Ju; Lu, Chi-Yu; Tseng, Wei-Lung

    2014-10-22

    This study describes a simple method for removing mercuric ions (Hg(2+)) from a high-salt matrix based on the use of Tween-20-stabilized gold nanoparticles (Tween 20-Au NPs) as Hg(2+) adsorbents and composites of reduced graphite oxide and Fe3O4 NPs as NP collectors. Citrate ions adsorbed on the surface of the Tween 20-Au NPs reduced Hg(2+) to Hg(0), resulting in the deposition of Hg(0) on the surface of the NPs. To circumvent time-consuming centrifugation and transfer steps, the Hg(0)-containing gold NPs were collected using reduced graphite oxide-Fe3O4 NP composites. Compared with the reported NP-based methods for removing Hg(2+), Tween 20-Au NPs offered the rapid (within 30 min), efficient (>99% elimination efficiency), durable (>10 cycles), and selective removal of Hg(2+), CH3Hg(+), and C2H5Hg(+) in a high-salt matrix without the interference of other metal ions. This was attributed to the fact that the dispersed Tween 20-Au NPs exhibited large surface-area-to-volume ratio to bind Hg(2+) through Hg(2+)-Au(+) metallophilic interactions in a high-salt matrix. The formation of graphite oxide sheets and reduced graphite oxide-Fe3O4 NP composites was demonstrated using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectrometry, and transmission electron microscopy. The mechanism of interaction between Tween 20-Au NPs and Hg(2+) was studied using visible spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. PMID:25238563

  19. A Fe3O4/FeAl2O4 composite coating via plasma electrolytic oxidation on Q235 carbon steel for Fenton-like degradation of phenol.

    PubMed

    Wang, Jiankang; Yao, Zhongping; Yang, Min; Wang, Yajing; Xia, Qixing; Jiang, Zhaohua

    2016-08-01

    The Fe3O4/FeAl2O4 composite coatings were successfully fabricated on Q235 carbon steel by plasma electrolytic oxidation technique and used to degrade phenol by Fenton-like system. XRD, SEM, and XPS indicated that Fe3O4 and FeAl2O4 composite coating had a hierarchical porous structure. The effects of various parameters such as pH, phenol concentration, and H2O2 dosage on catalytic activity were investigated. The results indicated that with increasing of pH and phenol content, the phenol degradation efficiency was reduced significantly. However, the degradation rate was improved with the addition of H2O2, but dropped with further increasing of H2O2. Moreover, 100 % removal efficiency with 35 mg/L phenol was obtained within 60 min at 303 K and pH 4.0 with 6.0 mmol/L H2O2 on 6-cm(2) iron oxide coating. The degradation process consisted of induction period and rapid degradation period; both of them followed pseudo-first-order reaction. Hydroxyl radicals were the mainly oxidizing species during phenol degradation by using n-butanol as hydroxyl radical scavenger. Based on Fe leaching and the reaction kinetics, a possible phenol degradation mechanism was proposed. The catalyst exhibited excellent stability. PMID:27074928

  20. Magnetite Fe3O4 nanoparticles synthesis by wet chemical reduction and their characterization

    NASA Astrophysics Data System (ADS)

    Chaki, S. H.; Malek, Tasmira J.; Chaudhary, M. D.; Tailor, J. P.; Deshpande, M. P.

    2015-09-01

    The authors report the synthesis of Fe3O4 nanoparticles by wet chemical reduction technique at ambient temperature and its characterization. Ferric chloride hexa-hydrate (FeCl3 · 6H2O) and sodium boro-hydrate (NaBH4) were used for synthesis of Fe3O4 nanoparticles at ambient temperature. The elemental composition of the synthesized Fe3O4 nanoparticles was determined by energy dispersive analysis of x-rays technique. The x-ray diffraction (XRD) technique was used for structural characterization of the nanoparticles. The crystallite size of the nanoparticles was determined using XRD data employing Scherrer’s formula and Hall-Williamson’s plot. Surface morphology of as-synthesized Fe3O4 nanoparticles was studied by scanning electron microscopy. High resolution transmission electron microscopy analysis of the as-synthesized Fe3O4 nanoparticles showed narrow range of particles size distribution. The optical absorption of the synthesized Fe3O4 nanoparticles was studied by UV-vis-NIR spectroscopy. The as-synthesized nanoparticles were analyzed by Fourier transform infrared spectroscopy technique for absorption band study in the infrared region. The magnetic properties of the as-synthesized Fe3O4 nanoparticles were evaluated by vibrating sample magnetometer technique. The thermal stability of the as-synthesized Fe3O4 nanoparticles was studied by thermogravimetric technique. The obtained results are elaborated and discussed in details in this paper.

  1. Dielectric and conductivity characteristics of CuCl2 doped poly(N-vinyl carbazole) and its hybrid nanocomposite with Fe3O4.

    PubMed

    Haldar, Ipsita; Biswas, Mukul; Nayak, Arabinda

    2014-08-01

    Copper(II) chloride (CuCl2) doped poly(N-vinyl carbazole) (PNVC)-ferric oxide (Fe3O4) hybrid composites have been prepared and characterized by Fourier transform infrared spectroscopic studies, UV-Vis spectroscopy, high resolution transmission electron microscopy (HRTEM) and X-ray diffraction analyses and evaluated in regard to dielectric response and ac/dc conductivity characteristics. HRTEM images for CuCl2-(PNVC-Fe3O4) composite indicate the co-existence of both the CuCl2 and Fe3O4 nanoparticles in the composite and characteristic lattice fringes are clearly observed which endorse the formation of thin layer interfaces between Fe3O4 and CuCl2 nanoparticles. The dielectric constants of the CuCl2 doped PNVC and PNVC-Fe3O4 composites increase substantially relative to the corresponding values of the polymer and the polymer composite respectively. Likewise, the conductivities (ac and dc) are also improved substantially after doping with CuCl2. The dependence of these functional properties on the extent of metal salt loading has been evaluated and a quantitative estimation of the contribution of the grain boundary and resistance parameters has been attempted in terms of Maxwell-Wagner two-layered model. PMID:25936001

  2. Synthesis, characterization and properties of ethylenediamine-functionalized Fe3O4 magnetic polymers for removal of Cr(VI) in wastewater.

    PubMed

    Zhao, Yong-Gang; Shen, Hao-Yu; Pan, Sheng-Dong; Hu, Mei-Qin

    2010-10-15

    A series of ethylenediamine (EDA)-functionalized magnetic polymers (EDA-MPs) have been prepared via suspension polymerization with the usage amount of the functional monomer glycidylmethacrylate (GMA) varied during the suspension polymerization procedure. The EDA-MPs were characterized by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), X-ray diffractometer (XRD), thermogravimetry and differential thermogravimetry analysis (TG-DTA), Fourier-transformed infrared spectroscopy (FTIR) and elementary analyzer (EA). The adsorption properties of the EDA-MPs for the removal of Cr(VI) in wastewater were deeply studied. The results showed the adsorption efficiency was highly pH dependent and decreased with the increasing of initial concentration of Cr(VI). The adsorption data taken at the optimized condition, i.e., 35 degrees C and pH of 2.5 were well fitted with the Langmuir isotherm. The maximum adsorption capacities (q(m)) of EDA-MPs to Cr(VI) were highly related to the contents of EDA-MPs, i.e., the q(m) of EDA-MPs to Cr(VI) calculated from the Langmuir isotherm increased from 32.15 to 61.35 mg g(-1) with the increasing of the usage amount of GMA. The adsorption kinetic data were modeled by the pseudo-second-order rate equation, and the adsorption of Cr(VI) by all the present EDA-MPs reached equilibrium in 60 min. PMID:20621418

  3. Oxidase-functionalized Fe(3)O(4) nanoparticles for fluorescence sensing of specific substrate.

    PubMed

    Liu, Cheng-Hao; Tseng, Wei-Lung

    2011-10-01

    This study reports the development of a reusable, single-step system for the detection of specific substrates using oxidase-functionalized Fe(3)O(4) nanoparticles (NPs) as a bienzyme system and using amplex ultrared (AU) as a fluorogenic substrate. In the presence of H(2)O(2), the reaction pH between Fe(3)O(4) NPs and AU was similar to the reaction of oxidase and the substrate. The catalytic activity of Fe(3)O(4) NPs with AU was nearly unchanged following modification with poly(diallyldimethylammonium chloride) (PDDA). Based on these features, we prepared a composite of PDDA-modified Fe(3)O(4) NPs and oxidase for the quantification of specific substrates through the H(2)O(2)-mediated oxidation of AU. By monitoring fluorescence intensity at 587 nm of oxidized AU, the minimum detectable concentrations of glucose, galactose, and choline were found to be 3, 2, and 20 μM using glucose oxidase-Fe(3)O(4), galactose oxidase-Fe(3)O(4), and choline oxidase-Fe(3)O(4) composites, respectively. The identification of glucose in blood was selected as the model to validate the applicability of this proposed method. PMID:21843679

  4. Enhanced UV Photocatalytic Performance of Magnetic Fe3O4/CuO/ZnO/NGP Nanocomposites

    NASA Astrophysics Data System (ADS)

    Tju, Hendry; Taufik, Ardiansyah; Saleh, Rosari

    2016-04-01

    Fe3O4/CuO/ZnO/nanographene platelets (Fe3O4/CuO/ZnO/NGP) with varied ZnO loadings have been synthesized using a sol-gel method followed by hydrothermal method. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) confirmed the formation of the Fe3O4/CuO/ZnO/NGP composites. All of the samples showed the presence of graphene nanoplatelets incorporating Fe3O4, CuO and ZnO structures and exhibited ferromagnetic behavior at room temperature. The composites showed photocatalytic activity under UV irradiation, which was used to affect the degradation of methylene blue. The Fe3O4/CuO/ZnO/NGP composites showed superior photocatalytic activity than the Fe3O4/CuO/ZnO materials.

  5. Preparation and electrochemical property of Fe3O4/MWCNT nanocomposite

    NASA Astrophysics Data System (ADS)

    Zhao, Tingkai; Ji, Xianglin; Guo, Xinai; Jin, Wenbo; Dang, Alei; Li, Hao; Li, Tiehu

    2016-06-01

    Ferroferric oxide (Fe3O4)/functionalized multi-walled carbon nanotube (f-MWCNT) nanomaterials were synthesized by chemical deposition & hydrothermal method. Fe3O4/f-MWCNT composites possess the same ferrimagnetism as pure Fe3O4, and the composites will present certain orientation in magnetism. The saturation magnetization (Ms) is about 48.84 emu g-1 and the coercivity (Hc) is 19.19 Oe. The electrochemical analysis displays that the glassy carbon electrode coated with Fe3O4/f-MWCNT composite has a favorable promotion for the electrochemical response of H2O2. This process not only widely improved the redox current of H2O2, but also reduced the overpotential of redox process.

  6. Synergistic removal of Pb(II), Cd(II) and humic acid by Fe3O4@mesoporous silica-graphene oxide composites.

    PubMed

    Wang, Yilong; Liang, Song; Chen, Bingdi; Guo, Fangfang; Yu, Shuili; Tang, Yulin

    2013-01-01

    The synergistic adsorption of heavy metal ions and humic acid can be very challenging. This is largely because of their competitive adsorption onto most adsorbent materials. Hierarchically structured composites containing polyethylenimine-modified magnetic mesoporous silica and graphene oxide (MMSP-GO) were here prepared to address this. Magnetic mesoporous silica microspheres were synthesized and functionalized with PEI molecules, providing many amine groups for chemical conjugation with the carboxyl groups on GO sheets and enhanced the affinity between the pollutants and the mesoporous silica. The features of the composites were characterized using TEM, SEM, TGA, DLS, and VSM measurements. Series adsorption results proved that this system was suitable for simultaneous and efficient removal of heavy metal ions and humic acid using MMSP-GO composites as adsorbents. The maximum adsorption capacities of MMSP-GO for Pb(II) and Cd (II) were 333 and 167 mg g(-1) caculated by Langmuir model, respectively. HA enhances adsorption of heavy metals by MMSP-GO composites due to their interactions in aqueous solutions. The underlying mechanism of synergistic adsorption of heavy metal ions and humic acid were discussed. MMSP-GO composites have shown promise for use as adsorbents in the simultaneous removal of heavy metals and humic acid in wastewater treatment processes. PMID:23776514

  7. Synergistic Removal of Pb(II), Cd(II) and Humic Acid by Fe3O4@Mesoporous Silica-Graphene Oxide Composites

    PubMed Central

    Wang, Yilong; Liang, Song; Chen, Bingdi; Guo, Fangfang; Yu, Shuili; Tang, Yulin

    2013-01-01

    The synergistic adsorption of heavy metal ions and humic acid can be very challenging. This is largely because of their competitive adsorption onto most adsorbent materials. Hierarchically structured composites containing polyethylenimine-modified magnetic mesoporous silica and graphene oxide (MMSP-GO) were here prepared to address this. Magnetic mesoporous silica microspheres were synthesized and functionalized with PEI molecules, providing many amine groups for chemical conjugation with the carboxyl groups on GO sheets and enhanced the affinity between the pollutants and the mesoporous silica. The features of the composites were characterized using TEM, SEM, TGA, DLS, and VSM measurements. Series adsorption results proved that this system was suitable for simultaneous and efficient removal of heavy metal ions and humic acid using MMSP-GO composites as adsorbents. The maximum adsorption capacities of MMSP-GO for Pb(II) and Cd (II) were 333 and 167 mg g−1 caculated by Langmuir model, respectively. HA enhances adsorption of heavy metals by MMSP-GO composites due to their interactions in aqueous solutions. The underlying mechanism of synergistic adsorption of heavy metal ions and humic acid were discussed. MMSP-GO composites have shown promise for use as adsorbents in the simultaneous removal of heavy metals and humic acid in wastewater treatment processes. PMID:23776514

  8. One-pot synthesis of a rose-like Pd-Fe3O4 nanocatalyst for Sonogashira coupling reactions

    NASA Astrophysics Data System (ADS)

    Woo, Hyunje; Lee, Kyoungho; Park, Ji Chan; Park, Kang Hyun

    2016-03-01

    A one-pot synthesis of rose-like Pd-Fe3O4 nanocomposites via the controlled thermal decomposition of Fe(CO)5 and reduction of Pd(OAc)2 is reported. This rose-like Pd-Fe3O4 composite structure has a high surface area owing to the individual Pd-Fe3O4 nanosheets, which imparted a high catalytic activity for Sonogashira coupling reactions. Moreover, the catalyst also demonstrated magnetic recyclability.

  9. Dopamine as the coating agent and carbon precursor for the fabrication of N-doped carbon coated Fe3O4 composites as superior lithium ion anodes

    NASA Astrophysics Data System (ADS)

    Lei, Cheng; Han, Fei; Li, Duo; Li, Wen-Cui; Sun, Qiang; Zhang, Xiang-Qian; Lu, An-Hui

    2013-01-01

    Dopamine is an excellent and flexible agent for surface coating of inorganic nanoparticles and contains unusually high concentrations of amine groups. In this study, we demonstrate that through a controlled coating of a thin layer of polydopamine on the surface of α-Fe2O3 in the dopamine aqueous solution, followed by subsequent carbonization, N-doped carbon-encapsulated magnetite has been synthesized and shows excellent electrochemical performance as anode material for lithium-ion batteries. Due to the strong binding affinity to iron oxide and excellent coating capability of this new carbon precursor, the conformal polydopamine derived carbon is continuous and uniform, and its thickness can be tailored. Moreover, due to the high percentage of nitrogen content in the precursor, the resulting carbon layer contains a moderate amount of N species, which can substantially improve the electrochemical performance. The composites synthesized by this facile method exhibit superior electrochemical performance, including remarkably high specific capacity (>800 mA h g-1 at a current of 500 mA g-1), high rate capability (595 and 396 mA h g-1 at a current of 1000 and 2000 mA g-1, respectively) and excellent cycle performance (200 cycles with 99% capacity retention), which adds to the potential as promising anodes for the application in lithium-ion batteries.Dopamine is an excellent and flexible agent for surface coating of inorganic nanoparticles and contains unusually high concentrations of amine groups. In this study, we demonstrate that through a controlled coating of a thin layer of polydopamine on the surface of α-Fe2O3 in the dopamine aqueous solution, followed by subsequent carbonization, N-doped carbon-encapsulated magnetite has been synthesized and shows excellent electrochemical performance as anode material for lithium-ion batteries. Due to the strong binding affinity to iron oxide and excellent coating capability of this new carbon precursor, the conformal

  10. Fabrication of mesoporous SiO(2)-C-Fe(3)O(4)/gamma-Fe(2)O(3) and SiO(2)-C-Fe magnetic composites.

    PubMed

    Sevilla, Marta; Valdés-Solís, Teresa; Tartaj, Pedro; Fuertes, Antonio B

    2009-12-15

    A synthetic method for the fabrication of silica-based mesoporous magnetic (Fe or iron oxide spinel) nanocomposites with enhanced adsorption and magnetic capabilities is presented. The successful in situ synthesis of magnetic nanoparticles is a consequence of the incorporation of a small amount of carbon into the pores of the silica, this step being essential for the generation of relatively large iron oxide magnetic nanocrystals ( approximately 10+/-3nm) and for the formation of iron nanoparticles. These composites combine good magnetic properties (superparamagnetic behaviour in the case of SiO(2)-C-Fe(3)O(4)/gamma-Fe(2)O(3) samples) with a large and accessible porosity made up of wide mesopores (>9nm). In the present work, we have demonstrated the usefulness of this kind of composite for the adsorption of a globular protein (hemoglobin). The results obtained show that a significant amount of hemoglobin can be immobilized within the pores of these materials (up to 180mgg(-1) for some of the samples). Moreover, we have proved that the composite loaded with hemoglobin can be easily manipulated by means of an external magnetic field. PMID:19781711

  11. Intercalating graphene with clusters of Fe3O4 nanocrystals for electrochemical supercapacitors

    NASA Astrophysics Data System (ADS)

    Ke, Qingqing; Tang, Chunhua; Liu, Yanqiong; Liu, Huajun; Wang, John

    2014-04-01

    A hierarchical nanostructure consisting of graphene sheets intercalated by clusters of Fe3O4 nanocystals is developed for high-performance supercapacitor electrode. Here we show that the negatively charged graphene oxide (GO) and positively charged Fe3O4 clusters enable a strong electrostatic interaction, generating a hierarchical 3D nanostructure, which gives rise to the intercalated composites through a rational hydrothermal process. The electrocapacitive behavior of the resultant composites is systematically investigated by cyclic voltammeter and galvanostatic charge-discharge techniques, where a positive synergistic effect between graphene and Fe3O4 clusters is identified. A maximum specific capacitance of 169 F g-1 is achieved in the Fe3O4 clusters decorated with effectively reduced graphene oxide (Fe3O4-rGO-12h), which is much higher than those of rGO (101 F g-1) and Fe3O4 (68 F g-1) at the current density of 1 Ag-1. Moreover, this intercalated hierarchical nanostructure demonstrates a good capacitance retention, retaining over 88% of the initial capacity after 1000 cycles.

  12. Ni doped Fe3O4 magnetic nanoparticles.

    PubMed

    Larumbe, S; Gómez-Polo, C; Pérez-Landazábal, J I; García-Prieto, A; Alonso, J; Fdez-Gubieda, M L; Cordero, D; Gómez, J

    2012-03-01

    In this work, the effect of nickel doping on the structural and magnetic properties of Fe3O4 nanoparticles is analysed. Ni(x)Fe(3-x)O4 nanoparticles (x = 0, 0.04, 0.06 and 0.11) were obtained by chemical co-precipitation method, starting from a mixture of FeCl2 x 4H2O and Ni(AcO)2 x 4H2O salts. The analysis of the structure and composition of the synthesized nanoparticles confirms their nanometer size (main sizes around 10 nm) and the inclusion of the Ni atoms in the characteristic spinel structure of the magnetite Fe3O4 phase. In order to characterize in detail the structure of the samples, X-ray absorption (XANES) measurements were performed on the Ni and Fe K-edges. The results indicate the oxidation of the Ni atoms to the 2+ state and the location of the Ni2+ cations in the Fe2+ octahedral sites. With respect to the magnetic properties, the samples display the characteristic superparamagnetic behaviour, with anhysteretic magnetic response at room temperature. The estimated magnetic moment confirms the partial substitution of the Fe2+ cations by Ni2+ atoms in the octahedral sites of the spinel structure. PMID:22755104

  13. Size-Controllable Synthesis of Fe3O4 Nanospheres for Electromagnetic Wave Absorber

    NASA Astrophysics Data System (ADS)

    Wang, Yanping; Sun, Danping; Liu, Gongzong; Wang, Yujiao; Jiang, Wei

    2015-07-01

    We present a hydrothermal method to control the size of Fe3O4 nanospheres by adjusting the concentration of FeCl3·6H2O in ethylene glycol/diethylene glycol binary solvent mixtures. The electromagnetic wave absorption properties of Fe3O4 nanospheres of different diameters have been investigated using a vector network analyzer. The reflection loss of Fe3O4 nanospheres/paraffin wax composite can reach as high as -30.00 dB at 17.50 GHz and -37.95 dB at 7.67 GHz for Fe3O4 nanospheres with diameter of about 120 nm and 170 nm, respectively. The absorption bandwidth with reflection loss below -10 dB is up to 7.01 GHz when the Fe3O4 diameter is about 220 nm. In contrast, the bandwidth decreased to 4.28 GHz when the size shrank to 70 nm. Therefore, our method can be utilized to precisely control the size of Fe3O4 nanospheres in order to manipulate their electromagnetic wave absorption properties.

  14. Determination of trace/ultratrace rare earth elements in environmental samples by ICP-MS after magnetic solid phase extraction with Fe3O4@SiO2@polyaniline-graphene oxide composite.

    PubMed

    Su, Shaowei; Chen, Beibei; He, Man; Hu, Bin; Xiao, Zuowei

    2014-02-01

    A novel Fe3O4@SiO2@polyaniline-graphene oxide composite (MPANI-GO) was prepared through a simple noncovalent method and applied to magnetic solid phase extraction (MSPE) of trace rare earth elements (REEs) in tea leaves and environmental water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. The prepared MPANI-GO was characterized by transmission electron microscopy and vibrating sample magnetometer. Various parameters affecting MPANI-GO MSPE of REEs have been investigated. Under the optimized conditions, the limits of detection (LODs, 3σ) for REEs were in the range of 0.04-1.49 ng L(-1) and the relative standard deviations (RSDs, c=20 ng L(-1), n=7) were 1.7-6.5%. The accuracy of the proposed method was validated by analyzing a Certified Reference Material of GBW 07605 tea leaves. The method was also successfully applied for the determination of trace REEs in tea leaves and environmental water samples. The developed MPANI-GO MSPE-ICP-MS method has the advantages of simplicity, rapidity, high sensitivity, high enrichment factor and is suitable for the analysis of trace REEs in samples with complex matrix. PMID:24401441

  15. Spin-dependent transport properties of Fe3O4/MoS2/Fe3O4 junctions

    NASA Astrophysics Data System (ADS)

    Wu, Han-Chun; Coileáin, Cormac Ó.; Abid, Mourad; Mauit, Ozhet; Syrlybekov, Askar; Khalid, Abbas; Xu, Hongjun; Gatensby, Riley; Jing Wang, Jing; Liu, Huajun; Yang, Li; Duesberg, Georg S.; Zhang, Hong-Zhou; Abid, Mohamed; Shvets, Igor V.

    2015-11-01

    Magnetite is a half-metal with a high Curie temperature of 858 K, making it a promising candidate for magnetic tunnel junctions (MTJs). Yet, initial efforts to exploit its half metallic nature in Fe3O4/MgO/Fe3O4 MTJ structures have been far from promising. Finding suitable barrier layer materials, which keep the half metallic nature of Fe3O4 at the interface between Fe3O4 layers and barrier layer, is one of main challenges in this field. Two-dimensional (2D) materials may be good candidates for this purpose. Molybdenum disulfide (MoS2) is a transition metal dichalcogenide (TMD) semiconductor with distinctive electronic, optical, and catalytic properties. Here, we show based on the first principle calculations that Fe3O4 keeps a nearly fully spin polarized electron band at the interface between MoS2 and Fe3O4. We also present the first attempt to fabricate the Fe3O4/MoS2/Fe3O4 MTJs. A clear tunneling magnetoresistance (TMR) signal was observed below 200 K. Thus, our experimental and theoretical studies indicate that MoS2 can be a good barrier material for Fe3O4 based MTJs. Our calculations also indicate that junctions incorporating monolayer or bilayer MoS2 are metallic.

  16. Spin-dependent transport properties of Fe3O4/MoS2/Fe3O4 junctions

    PubMed Central

    Wu, Han-Chun; Coileáin, Cormac Ó; Abid, Mourad; Mauit, Ozhet; Syrlybekov, Askar; Khalid, Abbas; Xu, Hongjun; Gatensby, Riley; Jing Wang, Jing; Liu, Huajun; Yang, Li; Duesberg, Georg S.; Zhang, Hong-Zhou; Abid, Mohamed; Shvets, Igor V.

    2015-01-01

    Magnetite is a half-metal with a high Curie temperature of 858 K, making it a promising candidate for magnetic tunnel junctions (MTJs). Yet, initial efforts to exploit its half metallic nature in Fe3O4/MgO/Fe3O4 MTJ structures have been far from promising. Finding suitable barrier layer materials, which keep the half metallic nature of Fe3O4 at the interface between Fe3O4 layers and barrier layer, is one of main challenges in this field. Two-dimensional (2D) materials may be good candidates for this purpose. Molybdenum disulfide (MoS2) is a transition metal dichalcogenide (TMD) semiconductor with distinctive electronic, optical, and catalytic properties. Here, we show based on the first principle calculations that Fe3O4 keeps a nearly fully spin polarized electron band at the interface between MoS2 and Fe3O4. We also present the first attempt to fabricate the Fe3O4/MoS2/Fe3O4 MTJs. A clear tunneling magnetoresistance (TMR) signal was observed below 200 K. Thus, our experimental and theoretical studies indicate that MoS2 can be a good barrier material for Fe3O4 based MTJs. Our calculations also indicate that junctions incorporating monolayer or bilayer MoS2 are metallic. PMID:26522127

  17. Synthesis and characterizations of Fe3O4-acid fuchsin tagged poly(ɛ-caprolactone) nanocomposites

    NASA Astrophysics Data System (ADS)

    Meenarathi, Balakrishnan; Kannammal, Lingasamy; Palanikumar, Shanmugavel; Anbarasan, Ramasamy

    2014-04-01

    Ring opening polymerization (ROP) of caprolactone (CL) was carried out at different experimental conditions such as variation in [M], [M/I] and temperature under N2 atmosphere at 160 °C for 2 h with mild stirring condition by using acid fuchsin (AF) decorated Fe3O4 as a novel chemical initiator with the aid of stannous octoate as an effective catalyst. Thus, prepared polymer nano composite samples were characterised by various analytical techniques such as Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, UV-visible spectroscopy, fluorescence spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), vibrating sample measurement (VSM), scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM). Presence of Fe2p and Fe3p was confirmed by x-ray photoelectron spectroscopy (XPS) analysis. It was found that while increasing the [M/I] the melt transition values were increased. The surface catalytic effect of Fe3O4/AF hybrid system towards the ROP of CL was also studied.

  18. Polylactide-based polyurethane shape memory nanocomposites (Fe3O4/PLAUs) with fast magnetic responsiveness

    NASA Astrophysics Data System (ADS)

    Gu, Shu-Ying; Jin, Sheng-Peng; Gao, Xie-Feng; Mu, Jian

    2016-05-01

    Polylactide-based polyurethane shape memory nanocomposites (Fe3O4/PLAUs) with fast magnetic responsiveness are presented. For the purpose of fast response and homogeneous dispersion of magnetic nanoparticles, oleic acid was used to improve the dispersibility of Fe3O4 nanoparticles in a polymer matrix. A homogeneous distribution of Fe3O4 nanoparticles in the polymer matrix was obtained for nanocomposites with low Fe3O4 loading content. A small agglomeration was observed for nanocomposites with 6 wt% and 9 wt% loading content, leading to a small decline in the mechanical properties. PLAU and its nanocomposites have glass transition around 52 °C, which can be used as the triggering temperature. PLAU and its nanocomposites have shape fixity ratios above 99%, shape recovery ratios above 82% for the first cycle and shape recovery ratios above 91% for the second cycle. PLAU and its nanocomposites also exhibit a fast water bath or magnetic responsiveness. The magnetic recovery time decreases with an increase in the loading content of Fe3O4 nanoparticles due to an improvement in heating performance for increased weight percentage of fillers. The nanocomposites have fast responses in an alternating magnetic field and have potential application in biomedical areas such as intravascular stent.

  19. Biocompatibility of magnetic Fe3O4 nanoparticles and their cytotoxic effect on MCF-7 cells

    PubMed Central

    Chen, Daozhen; Tang, Qiusha; Li, Xiangdong; Zhou, Xiaojin; Zang, Jia; Xue, Wen-qun; Xiang, Jing-ying; Guo, Cai-qin

    2012-01-01

    Background The objective of this study was to evaluate the synthesis and biocompatibility of Fe3O4 nanoparticles and investigate their therapeutic effects when combined with magnetic fluid hyperthermia on cultured MCF-7 cancer cells. Methods Magnetic Fe3O4 nanoparticles were prepared using a coprecipitation method. The appearance, structure, phase composition, functional groups, surface charge, magnetic susceptibility, and release in vitro were characterized by transmission electron microscopy, x-ray diffraction, scanning electron microscopy-energy dispersive x-ray spectroscopy, and a vibrating sample magnetometer. Blood toxicity, in vitro toxicity, and genotoxicity were investigated. Therapeutic effects were evaluated by MTT [3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide] and flow cytometry assays. Results Transmission electron microscopy revealed that the shapes of the Fe3O4 nanoparticles were approximately spherical, with diameters of about 26.1 ± 5.2 nm. Only the spinel phase was indicated in a comparison of the x-ray diffraction data with Joint Corporation of Powder Diffraction Standards (JCPDS) X-ray powder diffraction files. The O-to-Fe ratio of the Fe3O4 was determined by scanning electron microscopy-energy dispersive x-ray spectroscopy elemental analysis, and approximated pure Fe3O4. The vibrating sample magnetometer hysteresis loop suggested that the Fe3O4 nanoparticles were superparamagnetic at room temperature. MTT experiments showed that the toxicity of the material in mouse fibroblast (L-929) cell lines was between Grade 0 to Grade 1, and that the material lacked hemolysis activity. The acute toxicity (LD50) was 8.39 g/kg. Micronucleus testing showed no genotoxic effects. Pathomorphology and blood biochemistry testing demonstrated that the Fe3O4 nanoparticles had no effect on the main organs and blood biochemistry in a rabbit model. MTT and flow cytometry assays revealed that Fe3O4 nano magnetofluid thermotherapy inhibited MCF-7

  20. Fe3O4@Carbon Nanosheets for All-Solid-State Supercapacitor Electrodes.

    PubMed

    Fan, Huailin; Niu, Ruiting; Duan, Jiaqi; Liu, Wei; Shen, Wenzhong

    2016-08-01

    Fe3O4@carbon nanosheet composites were synthesized using ammonium ferric citrate as the Fe3O4/carbon precursor and graphene oxide as the structure-directing agent under a hydrothermal process. The surface chemical compositions, pore structures, and morphology of the composite were analyzed and characterized by nitrogen adsorption isotherms, TG analysis, FT-IR, X-ray photoelectron energy spectrum, transmission electron microscopy, and scanning electron microscopy. The composites showed excellent specific capacitance of 586 F/g, 340 F/g at 0.5 A/g and 10 A/g. The all-solid-state asymmetric supercapacitor device assembled using carbon nanosheets in situ embedded Fe3O4 composite and porous carbon showed a largest energy density of 18.3 Wh/kg at power density of 351 W/kg in KOH/PVA gel electrolyte. The synergism of high special surface to volume ratio, mesoporous structure, graphene-based conduction paths, and Fe3O4 nanoparticles provided a high surface area of ion-accessibility, high electric conductivity, and the utmost utilization of Fe3O4 and resulted in excellent specific capacitance, outstanding rate capability and cycling life as all-solid-state supercapacitor electrodes. PMID:27406686

  1. Electrostatic Force Microscopy of Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Mottaghizadeh, A.; Lang, P. L.; Cui, L.; Lesueur, J.; Zimmers, A.; Aubin, H.; Li, J.; Zheng, D. N.; Rebuttini, V.; Pinna, N.

    2012-02-01

    The electronic compressibility is a fundamental property that characterizes the electronic properties of materials submitted to an external electric field. In metals (insulators), the electronic compressibility is large (small) and leads to a small (large) screening length. Variations of the screening length can be observed through measurements of the ``quantum'' capacitance between one material and a metallic counter-electrode. Using an Electrostatic Force Microscope (EFM), we measured maps of the local capacitance of 8 nm magnetite nanoparticles synthesized following the ``benzyl alcohol route'' deposited on a metallic substrate. Magnetite, an inverse spinel structure of composition Fe3O4, is a material with strongly correlated electronic properties and presents a metal-insulator transition at 120 K, the so-called Verwey transition. We present EFM measurements of these nanoparticles as a function of tip-sample distance and temperature.

  2. Low-temperature hydrothermal synthesis of α-Fe/Fe3O4 nanocomposite for fast Congo red removal.

    PubMed

    Wang, Lixia; Li, Jianchen; Wang, Zhitao; Zhao, Lijun; Jiang, Qing

    2013-02-21

    A facile low-temperature hydrothermal process to synthesize α-Fe/Fe(3)O(4) nanocomposite is reported. TEM and HRTEM revealed that the α-Fe/Fe(3)O(4) nanocomposite was composed of catenulate α-Fe and lamellar structured Fe(3)O(4). The weight ratio of α-Fe in the α-Fe/Fe(3)O(4) nanocomposite is 35.6%. The α-Fe/Fe(3)O(4) nanocomposite demonstrates an extremely high Congo red (CR) removal efficiency from waste water showing almost complete removal within 3 min. For 100 mg L(-1) of CR aqueous solution, the maximum CR removal can reach 1297.06 mg g(-1). The large saturation magnetization (80.5 emu g(-1)) of the nanocomposite allows fast separation of α-Fe/Fe(3)O(4) nanoparticles loaded with CR from the liquid suspension. The synergistic effect of the nanocomposite may contribute to the enhanced CR removal ability, because the CR can be removed by reduction reaction and adsorption at the same time. Based on the degradation products identified by UV-Vis spectra, XRD and FTIR spectra, a possible degradation mechanism of CR on the α-Fe/Fe(3)O(4) composite was proposed. The significantly reduced treatment time required to remove the CR and the simple, low-cost and pollution-free preparation method make α-Fe/Fe(3)O(4) nanocomposite promising for highly efficient removal of dyes from waste water. PMID:23223415

  3. Hybrid nanostructured C-dot decorated Fe3O4 electrode materials for superior electrochemical energy storage performance.

    PubMed

    Bhattacharya, K; Deb, P

    2015-05-21

    Research on energy storage devices has created a niche owing to the ever increasing demand for alternative energy production and its efficient utilisation. Here, a novel composite of Fe3O4 nanospheres and carbon quantum dots (C-dots) have been synthesized by a two step chemical route. Hybrids of C-dots with metal oxides can contribute to charge storage capacity through the combined effect of Faradaic pseudocapacitance from the Fe3O4 and the excellent electrical properties of the C-dots, which are a promising new member of the carbon family. The structural and morphological properties of the obtained Fe3O4-C hybrid nanocomposite were extensively studied. Detailed electrochemical studies show that the high performance of the magnetically responsive Fe3O4-C hybrid nanocomposite makes it an efficient supercapacitor electrode material. The remarkable improvement in the electrochemical performance of the Fe3O4-C hybrid nanocomposite is attributed to the Faradaic pseudocapacitance of Fe3O4 coupled with the high electrical conductivity of the C-dot which aided in fast transport and ionic motion during the charge-discharge cycles. Cyclic voltammetry and galvanostatic charge-discharge studies of Fe3O4-C hybrid nanocomposite show that the nanosystem delivers a maximum specific capacitance of ∼208 F g(-1). These results demonstrate that the novel Fe3O4-C hybrid nanocomposite has great potential as a high performance electrode material for supercapacitors. PMID:25909760

  4. Studies on the synthesis and microwave absorption properties of Fe3 O4/polyaniline FGM

    NASA Astrophysics Data System (ADS)

    Han, Xiao; Wang, Yuan-Sheng

    2007-12-01

    Electrically conducting polyaniline (PANI)-magnetic oxide (Fe3 O4) composites were synthesized by emulsion polymerization in the presence of dodecyl benzene sulfonic acid (DBSA) as the surfactant and dopant and ammonium persulfate (APS) as the oxidant. Transmission electron microscopy (TEM) indicates that the composite has a magnetic core and an electric shell and the modification has prevented the aggregation of Fe3 O4 nanoparticles effectively. The electromagnetic parameter measurements (ɛ'', ɛ', μ'' and μ') in the range of 2-18 GHz prove that Fe3 O4 in the Fe3 O4/PANI/DBSA is responsible for the electric and ferromagnetic behavior of the composites. As a result, the electromagnetic parameters can be designed by adjusting the content of the Fe3 O4. The microwave absorption of functionally graded material (FGM) was simulated by the computer according to the principle of impedance match and the calculated results agreed quite well with the experimentally measured data (R<-20 dB, Δf>4 GHz).

  5. Thermal decomposition study of Mn doped Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Malek, Tasmira J.; Chaki, S. H.; Tailor, J. P.; Deshpande, M. P.

    2016-05-01

    Fe3O4 is an excellent magnetic material among iron oxides. It has a cubic inverse spinel structure exhibiting distinguished electric and magnetic properties. In this paper the authors report the synthesis of Mn doped Fe3O4 nanoparticles by wet chemical reduction technique at ambient temperature and its thermal characterization. Ferric chloride hexa-hydrate (FeCl3•6H2O), manganese chloride tetra-hydrate (MnCl2•4H2O) and sodium boro-hydrate (NaBH4) were used for synthesis of Fe3O4 nanoparticles at ambient temperature. The elemental composition of the as-synthesized Mn doped Fe3O4 nanoparticles were determined by energy dispersive analysis of X-rays (EDAX) technique. Thermogravimetric (TG) and differential thermal analysis (DTA) were carried out on the Mn doped Fe3O4 nanoparticles in the temperature range of ambient to 1124 K. The thermo-curves revealed that the particles decompose by four steps. The kinetic parameters were evaluated using non-mechanistic equations for the thermal decomposition.

  6. A plasma protein corona enhances the biocompatibility of Au@Fe3O4 Janus particles.

    PubMed

    Landgraf, Lisa; Christner, Carolin; Storck, Wiebke; Schick, Isabel; Krumbein, Ines; Dähring, Heidi; Haedicke, Katja; Heinz-Herrmann, Karl; Teichgräber, Ulf; Reichenbach, Jürgen R; Tremel, Wolfgang; Tenzer, Stefan; Hilger, Ingrid

    2015-11-01

    Au@Fe3O4 Janus particles (JPs) are heteroparticles with discrete domains defined by different materials. Their tunable composition and morphology confer multimodal and versatile capabilities for use as contrast agents and drug carriers in future medicine. Au@Fe3O4 JPs have colloidal properties and surface characteristics leading to interactions with proteins in biological fluids. The resulting protein adsorption layer ("protein corona") critically affects their interaction with living matter. Although Au@Fe3O4 JPs displayed good biocompatibility in a standardized in vitro situation, an in-depth characterization of the protein corona is of prime importance to unravel underlying mechanisms affecting their pathophysiology and biodistribution in vitro and in vivo. Here, we comparatively analyzed the human plasma corona of Au-thiol@Fe3O4-SiO2-PEG JPs (NH2-functionalized and non-functionalized) and spherical magnetite (Fe3O4-SiO2-PEG) particles and investigated its effects on colloidal stability, biocompatibility and cellular uptake. Label-free quantitative proteomic analyses revealed that complex coronas including almost 180 different proteins were formed within only one minute. Remarkably, in contrast to spherical magnetite particles with surface NH2 groups, the Janus structure prevented aggregation and the adhesion of opsonins. This resulted in an enhanced biocompatibility of corona sheathed JPs compared to spherical magnetite particles and corona-free JPs. PMID:26276693

  7. Synthesis and properties of hybrid hydroxyapatite-ferrite (Fe3O4) particles for hyperthermia applications

    NASA Astrophysics Data System (ADS)

    Tkachenko, M. V.; Kamzin, A. S.

    2016-04-01

    Hybrid ceramics consisting of hydroxyapatite Ca10(PO4)6(OH)2 and ferrite Fe3O4 were synthesized using a two-stage procedure. The first stage included the synthesis of Fe3O4 ferrite particles by co-precipitation and the synthesis of hydroxyapatite. In the second stage, the magnetic hybrid hydroxyapatite-ferrite bioceramics were synthesized by a thorough mixing of the obtained powders of carbonated hydroxyapatite and Fe3O4 ferrite taken in a certain proportion, pressing into tablets, and annealing in a carbon dioxide atmosphere for 30 min at a temperature of 1200°C. The properties of the components and hybrid particles were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Mössbauer spectroscopy. The saturation magnetization of the hybrid ceramic composite containing 20 wt % Fe3O4 was found to be 12 emu/g. The hybrid hydroxyapatite (Ca10(PO4)6(OH)2)-ferrite Fe3O4 ceramics, which are promising for the use in magnetotransport and hyperthermia treatment, were synthesized and investigated for the first time.

  8. Magnetically Recyclable Fe3O4@His@Cu Nanocatalyst for Degradation of Azo Dyes.

    PubMed

    Kurtan, U; Amir, Md; Baykal, A; Sözeri, H; Toprak, M S

    2016-03-01

    Fe3O4@His@Cu magnetic recyclable nanocatalyst (MRCs) was synthesized by reflux method using L-histidine as linker. The composition, structure and magnetic property of the product were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM). Powder XRD, FT-IR and EDAX results confirmed that the as-synthesized products has Fe3O4 with spinel structure and Cu nanoparticles with moderate crystallinity without any other impurities. The surface of the Fe3O4@His nanocomposite was covered by tiny Cu nanoparticles. We examine the catalytic activity of Fe3O4@His@Cu MRCs for the degradation of two azo dyes, methyl orange (MO) and methylene blue (MB) as well as their mixture. The reusability of the nanocatalyst was good and sustained even after 3 cycles. Therefore this innovated Fe3O4@His@Cu MRCs has a potential to be used for purification of waste water. PMID:27455668

  9. Nanoparticle size matters in the formation of plasma protein coronas on Fe3O4 nanoparticles.

    PubMed

    Hu, Zhengyan; Zhang, Hongyan; Zhang, Yi; Wu, Ren'an; Zou, Hanfa

    2014-09-01

    When nanoparticles (NPs) enter into biological systems, proteins would interact with NPs to form the protein corona that can critically impact the biological identity of the nanomaterial. Owing to their fundamental scientific interest and potential applications, Fe3O4 NPs of different sizes have been developed for applications in cell separation and protein separation and as contrast agents in magnetic resonance imaging (MRI), etc. Here, we investigated whether nanoparticle size affects the formation of protein coronas around Fe3O4 NPs. Both the identification and quantification results demonstrated that particle size does play an important role in the formation of plasma protein coronas on Fe3O4 NPs; it not only influenced the protein composition of the formed plasma protein corona but also affected the abundances of the plasma proteins within the coronas. Understanding the different binding profiles of human plasma proteins on Fe3O4 NPs of different sizes would facilitate the exploration of the bio-distributions and biological fates of Fe3O4 NPs in biological systems. PMID:24974013

  10. Magnetic Fe3O4@chitosan nanoparticle: synthesis, characterization and application as catalyst carrier.

    PubMed

    He, Linghao; Yao, Lu; Liu, Fujun; Qin, Bing; Song, Rul; Huang, Wei

    2010-10-01

    A novel method was developed to prepare Fe3O4@CS beads with core-shell structure using a double-crosslinking process. Before the coating process, an unique crosslinking agent, glutaraldehyde (GA), was adsorbed onto the surface of Fe3O4 in advance, so the subsequent CS can uniformly coat around the magnetic core processed from the strong interaction between GA and CS, forming a perfect core-shell structure. The obtained Fe3O4@CS beads were followed by the Pd deposition through in-situ reduction method, and the prepared composite catalyst was applied exemplarily in synthesizing nabumetone to check its reusing property. The nanoparticles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and the magnetic hysteresis loop determination method. This novel composite catalyst showed admirable potential in reusable catalysis. PMID:21137729

  11. Fabrication highly dispersed Fe3O4 nanoparticles on carbon nanotubes and its application as a mimetic enzyme to degrade Orange II.

    PubMed

    Deng, Jingheng; Wen, Xianghua; Li, Jiaxi

    2016-09-01

    Fe3O4 nanoparticles were grown in situ on carbon nanotubes (CNTs) by a solvothermal method. The Fe3O4/CNTs composites were characterised by the Brunauer-Emmett-Teller method and transmission electron microscopy. The results indicated that the Fe3O4 nanoparticles were uniformly deposited on CNTs, and the average diameter was approximately 7.0 nm. The Fe3O4/CNTs were applied as an enzyme mimetic to decompose Orange II, and the decomposing conditions were optimised. At 500 mg L(-1) of Fe3O4/CNTs in the presence of 15.0 mmol L(-1) of H2O2, at 30°C, it degraded 94.0% of Orange II (0.25 mmol L(-1), pH = 3.5), showing higher catalytic activity than pure Fe3O4 nanoparticles. The high activity was attributed to the uniform Fe3O4 nanoparticles growing on the side walls of the CNTs and the synergetic effect between Fe3O4 and CNTs. The Fe3O4/CNTs maintained their activity at temperatures as high as 65°C. The Fe3O4/CNTs presented high reusability and stability even after eight uses. These data proved that the Fe3O4/CNTs-catalysed degradation is a promising technique for wastewater treatment. Fe3O4 nanoparticles were grown in situ on carbon nanotubes (CNTs) by a solvothermal method. The Fe3O4/CNTs was applied as a mimetic enzyme to decompose Orange II. The Fe3O4/CNTs were collected after the reaction by applying an external magnetic field and can use repeatedly. PMID:26828855

  12. In situ anchor of magnetic Fe3O4 nanoparticles onto natural maifanite as efficient heterogeneous Fenton-like catalyst

    NASA Astrophysics Data System (ADS)

    Zhao, Hang; Weng, Ling; Cui, Wei-Wei; Zhang, Xiao-Rui; Xu, Huan-Yan; Liu, Li-Zhu

    2016-06-01

    In situ anchor of magnetic Fe3O4 nanoparticles (NPs) onto the surface of natural maifanite was realized by chemical oxidation coprecipitation in hot alkaline solution. The Fe3O4/maifanite composites were characterized by XRD, FTIR, SEM, and TEM. These results indicated that polycrystalline Fe3O4 NPs with inverse spinel structure were formed and tightly dispersed on maifanite surface. Based on the measurement of surface Zeta potential of maifanite at different medium pHs, the possible combination mechanism between natural maifanite and Fe3O4 NPs was proposed. Then, the asobtained composites were developed as highly efficient heterogeneous Fenton-like catalyst for the discoloration of an azo dye, Methyl Orange (MO). The comparative tests on MO discoloration in different systems revealed that Fe3O4/maifanite composite exhibited much higher Fenton-like catalytic activity than Fe3O4 NPs and the heterogeneous Fentonlike reaction governed the discoloration of MO. Kinetic results clearly showed that MO discoloration process followed the second-order kinetic model. Fe3O4/maifanite composites exhibited the typical ferromagnetic property detected by VSM and could be easily separated from solution by an external magnetic field.

  13. In situ anchor of magnetic Fe3O4 nanoparticles onto natural maifanite as efficient heterogeneous Fenton-like catalyst

    NASA Astrophysics Data System (ADS)

    Zhao, Hang; Weng, Ling; Cui, Wei-Wei; Zhang, Xiao-Rui; Xu, Huan-Yan; Liu, Li-Zhu

    2016-09-01

    In situ anchor of magnetic Fe3O4 nanoparticles (NPs) onto the surface of natural maifanite was realized by chemical oxidation coprecipitation in hot alkaline solution. The Fe3O4/maifanite composites were characterized by XRD, FTIR, SEM, and TEM. These results indicated that polycrystalline Fe3O4 NPs with inverse spinel structure were formed and tightly dispersed on maifanite surface. Based on the measurement of surface Zeta potential of maifanite at different medium pHs, the possible combination mechanism between natural maifanite and Fe3O4 NPs was proposed. Then, the asobtained composites were developed as highly efficient heterogeneous Fenton-like catalyst for the discoloration of an azo dye, Methyl Orange (MO). The comparative tests on MO discoloration in different systems revealed that Fe3O4/maifanite composite exhibited much higher Fenton-like catalytic activity than Fe3O4 NPs and the heterogeneous Fentonlike reaction governed the discoloration of MO. Kinetic results clearly showed that MO discoloration process followed the second-order kinetic model. Fe3O4/maifanite composites exhibited the typical ferromagnetic property detected by VSM and could be easily separated from solution by an external magnetic field.

  14. Green synthesis and surface properties of Fe3O4@SA core-shell nanocomposites

    NASA Astrophysics Data System (ADS)

    Cao, Huimin; Li, Juchuan; Shen, Yuhua; Li, Shikuo; Huang, Fangzhi; Xie, Anjian

    2014-05-01

    In this paper, a one-step, economic and green approach was explored to prepare Fe3O4 nanoparticles by using L-cysteine as reducer and disperser without any inert gas protection. The Fe3O4 nanoparticles were then modified with stearic acid (SA) to form Fe3O4@SA core-shell nanocomposites. The experiment results indicate that the core-shell nanocomposites prepared could form monolayer on the water surface or films by means of Langmuir-Blodgett (LB) technology due to their hydrophobic and lipophilic properties. Also the composites exhibit paramagnetism, which make product dispersed stably in the oil medium to form magnetic fluid. Moreover, they are developed as sorbents to remove oil from water surface.

  15. Magnetically separable and recyclable Fe3O4-polydopamine hybrid hollow microsphere for highly efficient peroxidase mimetic catalysts.

    PubMed

    Liu, Shujun; Fu, Jianwei; Wang, Minghuan; Yan, Ya; Xin, Qianqian; Cai, Lu; Xu, Qun

    2016-05-01

    Magnetic Fe3O4-polydopamine (PDA) hybrid hollow microspheres, in which Fe3O4 nanoparticles were firmly incorporated in the cross-linked PDA shell, have been prepared through the formation of core/shell PS/Fe3O4-PDA composites based on template-induced covalent assembly method, followed by core removal in a tetrahydrofuran solution. The morphology, composition, thermal property and magnetic property of the magnetic hybrid hollow microspheres were characterized by SEM, TEM, FT-IR, XRD, TGA, and vibrating sample magnetometer, respectively. Results revealed that the magnetic hybrid hollow microspheres had about 380 nm of inner diameter and about 30 nm of shell thickness, and 13.6 emu g(-1) of magnetization saturation. More importantly, the Fe3O4-PDA hybrid hollow microspheres exhibited intrinsic peroxidase-like activity, as they could quickly catalyze the oxidation of typical substrates 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide. Compared with PDA/Fe3O4 composites where Fe3O4 nanoparticles were loaded on the surface of PDA microspheres, the stability of Fe3O4-PDA hybrid hollow microspheres was greatly improved. As-prepared magnetic hollow microspheres might open up a new application field in biodetection, biocatalysis, and environmental monitoring. PMID:26871276

  16. Controlled assembly of Fe3O4 magnetic nanoparticles on graphene oxide

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Chen, Biao; Zhang, Liming; Huang, Jie; Chen, Fenghua; Yang, Zupei; Yao, Jianlin; Zhang, Zhijun

    2011-04-01

    We describe a facile approach to controllable assembly of monodisperse Fe3O4nanoparticles (NPs) on chemically reduced graphene oxide (rGO). First, reduction and functionalization of GO by polyetheylenimine (PEI) were achieved simultaneously by simply heating the PEI and GO mixture at 60 °C for 12 h. The process is environmentally friendly and convenient compared with previously reported methods. Meso-2,3-dimercaptosuccinnic acid (DMSA)-modified Fe3O4 NPs were then conjugated to the PEI moiety which is located on the periphery of the GO sheets via formation of amide bonds between COOH groups of DMSA molecules bound on the surface of the Fe3O4 NPs and aminegroups of PEI. The magnetic GO composites were characterized by means of TEM, AFM, UV-vis, FTIR, Raman, TGA, and VSM measurements. Finally, preliminary results of using the Fe3O4-rGO composites for efficient removal of tetracycline, an antibiotic that is often found as a contaminant in the environment, are reported.We describe a facile approach to controllable assembly of monodisperse Fe3O4nanoparticles (NPs) on chemically reduced graphene oxide (rGO). First, reduction and functionalization of GO by polyetheylenimine (PEI) were achieved simultaneously by simply heating the PEI and GO mixture at 60 °C for 12 h. The process is environmentally friendly and convenient compared with previously reported methods. Meso-2,3-dimercaptosuccinnic acid (DMSA)-modified Fe3O4 NPs were then conjugated to the PEI moiety which is located on the periphery of the GO sheets via formation of amide bonds between COOH groups of DMSA molecules bound on the surface of the Fe3O4 NPs and aminegroups of PEI. The magnetic GO composites were characterized by means of TEM, AFM, UV-vis, FTIR, Raman, TGA, and VSM measurements. Finally, preliminary results of using the Fe3O4-rGO composites for efficient removal of tetracycline, an antibiotic that is often found as a contaminant in the environment, are reported. Electronic supplementary information

  17. Graphene-encapsulated Fe3O4 nanoparticles with 3D laminated structure as superior anode in lithium ion batteries.

    PubMed

    Wang, Jia-Zhao; Zhong, Chao; Wexler, David; Idris, Nurul Hayati; Wang, Zhao-Xiang; Chen, Li-Quan; Liu, Hua-Kun

    2011-01-10

    Fe(3)O(4)-graphene composites with three-dimensional laminated structures have been synthesised by a simple in situ hydrothermal method. From field-emission and transmission electron microscopy results, the Fe(3)O(4) nanoparticles, around 3-15 nm in size, are highly encapsulated in a graphene nanosheet matrix. The reversible Li-cycling properties of Fe(3)O(4)-graphene have been evaluated by galvanostatic discharge-charge cycling, cyclic voltammetry and impedance spectroscopy. Results show that the Fe(3)O(4)-graphene nanocomposite with a graphene content of 38.0 wt % exhibits a stable capacity of about 650 mAh  g(-1) with no noticeable fading for up to 100 cycles in the voltage range of 0.0-3.0 V. The superior performance of Fe(3)O(4)-graphene is clearly established by comparison of the results with those from bare Fe(3)O(4). The graphene nanosheets in the composite materials could act not only as lithium storage active materials, but also as an electronically conductive matrix to improve the electrochemical performance of Fe(3)O(4). PMID:21207587

  18. Facile synthesis of FeCo/Fe3O4 nanocomposite with high wave-absorbing properties.

    PubMed

    Gu, Yu; Cao, Yang; Chi, Huijuan; Liang, Qing; Zhang, Yongji; Sun, Youyi

    2013-01-01

    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. PMID:23839091

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

    PubMed Central

    Gu, Yu; Cao, Yang; Chi, Huijuan; Liang, Qing; Zhang, Yongji; Sun, Youyi

    2013-01-01

    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. PMID:23839091

  20. Synthesis and microwave absorption enhancement of graphene@Fe3O4@SiO2@NiO nanosheet hierarchical structures

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Huang, Ying; Sun, Xu; Huang, Haijian; Liu, Panbo; Zong, Meng; Wang, Yan

    2014-02-01

    Hierarchical structures of graphene@Fe3O4@SiO2@NiO nanosheets were prepared by combining the versatile sol-gel process with a hydrothermal reaction. Graphene@Fe3O4 composites were first synthesized by the reduction reaction between FeCl3 and diethylene glycol (DEG) in the presence of GO. Then, graphene@Fe3O4 was coated with SiO2 to obtain graphene@Fe3O4@SiO2. Finally, NiO nanosheets were grown perpendicularly on the surface of graphene@Fe3O4@SiO2 and graphene@Fe3O4@SiO2@NiO nanosheet hierarchical structures were formed. Moreover, the microwave absorption properties of both graphene@Fe3O4 and graphene@Fe3O4@SiO2@NiO nanosheets were investigated between 2 and 18 GHz microwave frequency bands. The electromagnetic data demonstrate that graphene@Fe3O4@SiO2@NiO nanosheet hierarchical structures exhibit significantly enhanced microwave absorption properties compared with graphene@Fe3O4, which probably originate from the unique hierarchical structure with a large surface area and high porosity.

  1. Thermodynamics of Fe3O4-Co3O4 and Fe3O4-Mn3O4 spinel solid solutions at the bulk and nanoscale.

    PubMed

    Sahu, Sulata K; Huang, Baiyu; Lilova, Kristina; Woodfield, Brian F; Navrotsky, Alexandra

    2015-09-14

    High temperature oxide melt solution calorimetry has been performed to investigate the enthalpies of mixing (ΔmixH) of bulk and nanophase (1 -x)Fe3O4-xM3O4 (M = Co, Mn) spinel solid solutions. The entropies of mixing (ΔmixS) were calculated from the configurational entropies based on cation distributions, and the Gibbs free energies of mixing (ΔmixG) were obtained. The ΔmixH and ΔmixG for the (1 -x)Fe3O4-xCo3O4 system are negative over the complete solid solution range, for both macroscopic and nanoparticulate materials. In (1 -x)Fe3O4-xMn3O4, the formation enthalpies of cubic Fe3O4 (magnetite) and tetragonal Mn3O4 (hausmannite) are negative for Mn3O4 mole fractions less than 0.67 and slightly positive for higher manganese content. Relative to cubic Fe3O4 and cubic Mn3O4 (stable at high temperature), the enthalpies and Gibbs energies of mixing are negative over the entire composition range. A combination of measured mixing enthalpies and reported Gibbs energies in the literature provides experimental entropies of mixing. The experimental entropies of mixing are consistent with those calculated from cation distributions for x > 0.3 but are smaller than those predicted for x < 0.3. This discrepancy may be related to the calculations, having treated Fe(2+) and Fe(3+) as distinguishable species. The measured surface energies of the (1 -x)Fe3O4-xM3O4 solid solutions are in the range of 0.6-0.9 J m(-2), similar to those of many other spinels. Because the surface energies are relatively constant, the thermodynamics of mixing at a given particle size throughout the solid solution can be considered independent of the particular particle size, thus confirming and extending the conclusions of a recent study on iron spinels. PMID:26245233

  2. Controlled assembly of Fe3O4 magnetic nanoparticles on graphene oxide.

    PubMed

    Zhang, Yi; Chen, Biao; Zhang, Liming; Huang, Jie; Chen, Fenghua; Yang, Zupei; Yao, Jianlin; Zhang, Zhijun

    2011-04-01

    We describe a facile approach to controllable assembly of monodisperse Fe(3)O(4) nanoparticles (NPs) on chemically reduced graphene oxide (rGO). First, reduction and functionalization of GO by polyetheylenimine (PEI) were achieved simultaneously by simply heating the PEI and GO mixture at 60 °C for 12 h. The process is environmentally friendly and convenient compared with previously reported methods. Meso-2,3-dimercaptosuccinnic acid (DMSA)-modified Fe(3)O(4) NPs were then conjugated to the PEI moiety which is located on the periphery of the GO sheets via formation of amide bonds between COOH groups of DMSA molecules bound on the surface of the Fe(3)O(4) NPs and amine groups of PEI. The magnetic GO composites were characterized by means of TEM, AFM, UV-vis, FTIR, Raman, TGA, and VSM measurements. Finally, preliminary results of using the Fe(3)O(4)-rGO composites for efficient removal of tetracycline, an antibiotic that is often found as a contaminant in the environment, are reported. PMID:21301708

  3. Surface controlled magnetic properties of Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Mohapatra, Jeotikanta; Mitra, Arijit; Bahadur, D.; Aslam, M.

    2013-02-01

    To understand the influence of surface organic-inorganic interactions on the magnetic properties of magnetic nanoparticles, magnetite (Fe3O4) of mean size 4-16 nm (standard deviation σ ≤ 15 %) are synthesized by three different thermolysis techniques. The surface functionality is controlled through either amine or amine-acid both taking as surfactant for Fe3O4 nanoparticles synthesis. Magnetic investigations revealed that samples prepared using amine as a multifunctional agent (only one surfactant) shows superior magnetic properties than the nanoparticles produced by the approach utilizing oleic acid and oleylamine.

  4. Photoluminescent Fe3O4/carbon nanocomposite with magnetic property.

    PubMed

    He, Xiaodie; Liu, Yang; Li, Haitao; Huang, Hui; Liu, Jinglin; Kang, Zhenhui; Lee, Shuit-Tong

    2011-04-01

    Fe(3)O(4)/carbon nanocomposite has been prepared by a facile chemical method, and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, fourier transform infrared spectroscopy and scanning electron microscopy. The fluorescent and magnetic properties of the sample were investigated by fluorescence spectroscopy and vibrating-sample magnetometer, respectively. The results indicate that the Fe(3)O(4)/carbon nanocomposite exhibit good photoluminescent (emission ranging from 425 to 550 nm) and strong magnetic (saturation magnetization of 44.2 emu/g) properties. PMID:21269640

  5. Bio and nanomaterials based on Fe3O4.

    PubMed

    Xu, Jia-Kun; Zhang, Fang-Fang; Sun, Jing-Jing; Sheng, Jun; Wang, Fang; Sun, Mi

    2014-01-01

    During the past few years, nanoparticles have been used for various applications including, but not limited to, protein immobilization, bioseparation, environmental treatment, biomedical and bioengineering usage, and food analysis. Among all types of nanoparticles, superparamagnetic iron oxide nanoparticles, especially Fe3O4, have attracted a great deal of attention due to their unique magnetic properties and the ability of being easily chemical modified for improved biocompatibility, dispersibility. This review covers recent advances in the fabrication of functional materials based on Fe3O4 nanoparticles together with their possibilities and limitations for application in different fields. PMID:25532846

  6. Au doping effect on the electrical and magnetic properties of Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Mahmood, Asif; Ramay, Shahid Mahmood; Al-Zaghayer, Yousef S.; Alhazaa, A. N.; Al Masary, Waheed A.; Atiq, Shahid

    2015-12-01

    Impurities free ferromagnetic Fe3O4 was prepared via sol-gel auto-combustion method and then gold was doped with various concentrations 1, 3 and 5 wt.% using conventional deposition-precipitation method. All samples of Fe3O4 with/without Au doping were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The room temperature magnetic hysteresis loops of all the samples were measured using a physical property measuring system (PPMS), and the results showed a ferromagnetic behavior at room temperature. The results obtained confirmed the fabrication of magnetite-gold composite nanoparticles. The results showed that the resistance and the magnetic behavior of the samples decrease sharply with the increase of Au concentration indicating semiconducting behavior. The saturation magnetization (Ms) of the bare Fe3O4 sample (94.72 emu/g) is much higher than that (66.78 emu/g) of the 5 wt.% Au-doped Fe3O4 sample.

  7. Effect of a SiO2 coating on the magnetic properties of Fe3O4 nanoparticles.

    PubMed

    Larumbe, S; Gómez-Polo, C; Pérez-Landazábal, J I; Pastor, J M

    2012-07-01

    In this work the effect of a SiO2 coating on the magnetic properties of Fe3O4 nanoparticles obtained by the sol-gel method is analyzed. Two sets of samples were prepared: Fe3O4 nanoparticles and Fe3O4@SiO2 core-shell composites. The samples display the characteristic spinel structure associated with the magnetite Fe3O4 phase, with the majority of grain sizes around 5-10 nm. At room temperature the nanoparticles show the characteristic superparamagnetic behavior with mean blocking temperatures around 160 and 120 K for Fe3O4 and Fe3O4@SiO2, respectively. The main effect of the SiO2 coating is reflected in the temperature dependence of the high field magnetization (μ(0)H = 6 T), i.e. deviations from the Bloch law at low temperatures (T < 20 K). Such deviations, enhanced by the introduction of the SiO2 coating, are associated with the occurrence of surface spin disordered effects. The induction heating effects (magnetic hyperthermia) are analyzed under the application of an AC magnetic field. Maximum specific absorption rate (SAR) values around 1.5 W g(-1) were achieved for the Fe3O4 nanoparticles. A significant decrease (around 26%) is found in the SAR values of the SiO2 coated nanocomposite. The different heating response is analyzed in terms of the decrease of the effective nanoparticle magnetization in the Fe3O4@SiO2 core-shell composites at room temperature. PMID:22700683

  8. Competing reactions of selected atmospheric gases on Fe3O4 nanoparticles surfaces.

    PubMed

    Eltouny, N; Ariya, Parisa A

    2014-11-14

    Heterogeneous reactions on atmospheric aerosol surfaces are increasingly considered important in understanding aerosol-cloud nucleation and climate change. To understand potential reactions in polluted atmospheres, the co-adsorption of NO2 and toluene to magnetite (Fe3O4i.e. FeO·Fe2O3) nanoparticles at ambient conditions was investigated for the first time. The surface area, size distribution, and morphology of Fe3O4 nanoparticles were characterized by BET method and high-resolution transmission electron microscopy. Adsorption isotherms, collected by gas chromatography with flame ionization detection, showed that the presence of NO2 decreased the adsorption of toluene. The analyses of the surface chemical composition of Fe3O4 by X-ray photoelectron spectroscopy (XPS) reveal that, upon the addition of NO2, the surface is oxidized and a contribution at 532.5 ± 0.4 eV in the O1s spectrum appears, showing that NO2 likely competes with toluene by dissociating on Fe(2+) sites and forming NO3(-). Different competing effects were observed for oxidized Fe3O4; oxidation occurred when exposed solely to NO2, whereas, the mixture of toluene and NO2 resulted in a reduction of the surface i.e. increased Fe(2+)/Fe(3+). Analyses by time of flight secondary ion mass spectrometry further suggest toluene reacts with Fe(3+) sites forming oxygenated organics. Our results indicate that on reduced magnetite, NO2 is more reactive and competes with toluene; in contrast, on oxidized Fe3O4, toluene is more reactive. Because magnetite can assume a range of oxidation ratios in the environment, different competing interactions between pollutants like NO2 and toluene could influence atmospheric processes, namely, the formation of Fe(2+) and the formation of atmospheric oxidants. PMID:25247461

  9. One-step thermolysis synthesis of two-dimensional ultrafine Fe3O4 particles/carbon nanonetworks for high-performance lithium-ion batteries.

    PubMed

    Zhang, Wanqun; Li, Xiaona; Liang, Jianwen; Tang, Kaibin; Zhu, Yongchun; Qian, Yitai

    2016-02-18

    To tackle the issue of inferior cycle stability and rate capability for Fe3O4 anode materials in lithium ion batteries, ultrafine Fe3O4 nanocrystals uniformly encapsulated in two-dimensional (2D) carbon nanonetworks have been fabricated through thermolysis of a simple, low-cost iron(iii) acetylacetonate without any extra processes. Moreover, compared to the reported Fe3O4/carbon composites, the particle size of Fe3O4 is controllable and held down to ∼3 nm. Benefitting from the synergistic effects of the excellent electroconductive carbon nanonetworks and uniform distribution of ultrafine Fe3O4 particles, the prepared 2D Fe3O4/carbon nanonetwork anode exhibits high reversible capacity, excellent rate capability and superior cyclability. A high capacity of 1534 mA h g(-1) is achieved at a 1 C rate and is maintained without decay up to 500 cycles (1 C = 1 A g(-1)). Even at the high current density of 5 C and 10 C, the 2D Fe3O4/carbon nanonetworks maintain a reversible capacity of 845 and 647 mA h g(-1) after 500 discharge/charge cycles, respectively. In comparison with other reported Fe3O4-based anodes, the 2D Fe3O4/carbon nanonetwork electrode is one of the most attractive of those in energy storage applications. PMID:26859122

  10. Luminescent and magnetic Fe3O4/Py/PAM nanocomposites for the chromium(VI) determination.

    PubMed

    Hong, Shi; Chen, Hongqi; Wang, Leyu; Wang, Lun

    2008-07-01

    A novel luminescent and magnetic Fe(3)O(4)/pyrene/polyacrylamide (Fe(3)O(4)/Py/PAM) nanocomposite has been prepared under ultrasonic radiation. This magnetic nanocomposite combined with pyrene would lead to a special functional magnetic luminescent composite that enjoys both the advantages of magnetic nanoparticles of Fe(3)O(4) and fluorescence nanoparticles of pyrene. Taking advantage of the magnetic property of Fe(3)O(4) nanocomposites, we can separate Fe(3)O(4)/Py/PAM nanocomposites from solution easily just by using a permanent magnet. Based on the fluorescence quenching of Fe(3)O(4)/Py/PAM nanocomposites by Cr(VI), a method for the selective determination of Cr(VI), without separation of Cr(III) in water, was developed. Under optimal experimental conditions, a limit of detection of 0.01 microg mL(-1) was achieved. The calibration curve was linear over the concentration range of 0.1-14.0 microg mL(-1) with a correlation coefficient of 0.9975. The proposed method has been applied to the selective quantification of Cr(VI) in synthetic samples and wastewater samples with the satisfactory results. PMID:18321770

  11. Synthesis and characterization of Fe3O4: Porous carbon nanocomposites for biosensor application

    NASA Astrophysics Data System (ADS)

    Arora, Manju; Zargar, R. A.

    2015-08-01

    Fe3O4:Porous carbon (Fe3O4:PC) nano-magnetic composites were prepared by using different weight fractions of acid treated PC by the chemical co-precipitation route and annealed at 573 K, 773 K and 973 K temperatures in inert N2 gas atmosphere for 2 hrs to obtain desired stoichiometry of nanocomposites. The structural, morphological and magnetic properties of these composites were characterized by powder XRD, TEM, EPR and VSM analytical techniques. The crystallinity of the composites, g-value and spin concentration increases with increasing annealing temperature. TEM images confirmed the formation of nanosized ferrite nanoprticles whose size increases from 23 nm to 54 nm on increasing annealing temperature. Porous carbon increases porosity, coercivity and reduces saturation magnetization of these prepared nanocomposites.

  12. Development of novel magnetic solid phase extraction materials based on Fe3O4/SiO2/poly(acrylamide-N,N'-methylene bisacrylamide)-Pluronic L64 composite microspheres and their application to the enrichment of natamycin.

    PubMed

    Tian, Miaomiao; Zou, Yongcun; Zhou, Shaoyan; Wang, Tianpeng; Lv, Xueju; Jia, Qiong

    2015-12-15

    Novel magnetic adsorbents based on Fe3O4/SiO2/poly(acrylamide-N,N'-methylene bisacrylamide) magnetic microspheres modified with non-ionic triblock copolymer surfactant were successfully prepared as a magnetic solid phase extraction adsorbent for the determination of trace natamycin in jam samples. The adsorbent was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transformed infrared spectroscopy, vibrating sample magnetometer, and X-ray diffractometer analysis, confirming that Pluronic L64 was effectively functionalized on the magnetic materials. Various experimental parameters affecting the extraction capacity were investigated including adsorbent amount, extraction time, desorption time, sample pH, and ionic strength. For recovery evaluations, the jam samples were spiked at two concentration levels of 100 and 200μgkg(-1) of natamycin and the recovery values were in the range of 78.8-93.4%. The relative standard deviations (RSD) for the recoveries were less than 3.5%. The novel magnetic solid phase extraction method provided several advantages, such as simplicity, low environmental impact, convenient extraction procedure, and short analysis time when used for natamycin analysis. PMID:26554702

  13. Synthesis and photocatalytic properties of Fe3O4@TiO2 core-shell for degradation of Rhodamine B

    NASA Astrophysics Data System (ADS)

    Mufti, Nandang; Munfarriha, Ulfatien; Fuad, Abdulloh; Diantoro, Markus

    2016-02-01

    The aim of this research is to synthesis Fe3O4@TiO2 core-shell and used it as photocatalytic for degradation of Rhodamine B. The Fe3O4 nanoparticle core was synthesized by coprecipitation method from the iron sand. The TiO2 shell synthesized using coprecipitation method to capsulated Fe3O4 nanoparticle with vary of Fe3O4 mass. The Fe3O4@TiO2 core-shells were characterized using SEM-EDX, XRD. Photocatalytic activity of Rhodamine B degradation was performed under UV irradiation with variation of time exposure. The efficiency of photodegradation is measured by UV-Vis spectrophotometer. The XRD result showed that Fe3O4 nanoparticle is single phase with crystal size of 15.5 nm. The existence of Fe3O4 and anatase of TiO2 phases in the XRD pattern shows that The Fe3O4@TiO2 core-shells are successfully synthesized. While, the TiO2 shell is confirmed by thermal test up to 550 OC for two hours to the samples. Based on SEM characterization, The Fe3O4@TiO2 core-shells are agglomerated with averages diameter sizes of particles between 38.5 nm to 72.8 nm. The concentration of TiO2 decrease with increasing Fe3O4 mass with atomic composition of Fe/Ti elements in Fe3O4@TiO2 core-shells are 0.083, 1.12, and 1.48. Based on photo degradation test of Rhodamine B under UV irradiation, we conclude that the degradation of Rhodamin B is caused by absorbsion and photocatalytic mechanism. For photocatalytic mechanism the efficiency of photodegradation of Rhodamin B increases by increasing TiO2 concentration.

  14. Formation and characterization of β-cyclodextrin (β-CD) - polyethyleneglycol (PEG) - polyethyleneimine (PEI) coated Fe3O4 nanoparticles for loading and releasing 5-Fluorouracil drug.

    PubMed

    Prabha, G; Raj, V

    2016-05-01

    In this work, β-cyclodextrin (β-CD) - polyethyleneglycol (PEG) - polyethyleneimine (PEI) coated iron oxide nanoparticles (Fe3O4-β-CD-PEG-PEI) were developed as drug carriers for drug delivery applications. The 5- Fluorouracil (5-FU) was chosen as model drug molecule. The developed nanoparticles (Fe3O4-β-CD-PEG-PEI) were characterized by various techniques such as Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The average particles size range of 5-FU loaded Fe3O4-β-CD, Fe3O4-β-CD-PEG and Fe3O4-β-CD-PEG-PEI nanoparticles were from 151 to 300nm and zeta potential value of nanoparticles were from -43mV to -20mV as measured using Malvern Zetasizer. Finally, encapsulation efficiency (EE), loading capacity (LC) and in-vitro drug release performance of 5-FU drug loaded Fe3O4-β-CD, Fe3O4-β-CD-PEG and Fe3O4-β-CD-PEG-PEI nanoparticles was evaluated by UV-vis spectroscopy. In-vitro cytotoxicity tests investigated by MTT assay indicate that 5-FU loaded Fe3O4-β-CD-PEG-PEI nanoparticles were toxic to cancer cells and non-toxic to normal cells. The in-vitro release behavior of 5-FU from drug (5-FU) loaded Fe3O4-β-CD-PEG-PEI composite at different pH values and temperature was studied. It was found that 5-FU was released faster in pH 6.8 than in the acidic mediums (pH 1.2), and the released quantity was higher. Therefore, the newly prepared Fe3O4-β-CD-PEG-PEI carrier exhibits a promising potential capability for anticancer drug delivery in tumor therapy. PMID:27133054

  15. Fe3O4-nanoparticles within porous silicon: Magnetic and cytotoxicity characterization

    NASA Astrophysics Data System (ADS)

    Granitzer, P.; Rumpf, K.; Tian, Y.; Akkaraju, G.; Coffer, J.; Poelt, P.; Reissner, M.

    2013-05-01

    The magnetic properties of porous silicon/Fe3O4 composites are investigated with respect to the adjustability of the blocking temperature along with an evaluation of any size-dependent changes in cytocompatibility. Fe3O4-nanoparticles have been infiltrated within mesoporous silicon, resulting in a system with tunable magnetic properties due to the matrix-morphology, the loading of the nanoparticles, and their size. In order to provide basic information regarding its suitability as a therapeutic platform, the cytotoxicity of these composites have been investigated by a trypan blue exclusion assay with respect to human embryonic kidney 293 cells, and the results compared with cell-only and known cytotoxic controls.

  16. One-step thermolysis synthesis of two-dimensional ultrafine Fe3O4 particles/carbon nanonetworks for high-performance lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Wanqun; Li, Xiaona; Liang, Jianwen; Tang, Kaibin; Zhu, Yongchun; Qian, Yitai

    2016-02-01

    To tackle the issue of inferior cycle stability and rate capability for Fe3O4 anode materials in lithium ion batteries, ultrafine Fe3O4 nanocrystals uniformly encapsulated in two-dimensional (2D) carbon nanonetworks have been fabricated through thermolysis of a simple, low-cost iron(iii) acetylacetonate without any extra processes. Moreover, compared to the reported Fe3O4/carbon composites, the particle size of Fe3O4 is controllable and held down to ~3 nm. Benefitting from the synergistic effects of the excellent electroconductive carbon nanonetworks and uniform distribution of ultrafine Fe3O4 particles, the prepared 2D Fe3O4/carbon nanonetwork anode exhibits high reversible capacity, excellent rate capability and superior cyclability. A high capacity of 1534 mA h g-1 is achieved at a 1 C rate and is maintained without decay up to 500 cycles (1 C = 1 A g-1). Even at the high current density of 5 C and 10 C, the 2D Fe3O4/carbon nanonetworks maintain a reversible capacity of 845 and 647 mA h g-1 after 500 discharge/charge cycles, respectively. In comparison with other reported Fe3O4-based anodes, the 2D Fe3O4/carbon nanonetwork electrode is one of the most attractive of those in energy storage applications.To tackle the issue of inferior cycle stability and rate capability for Fe3O4 anode materials in lithium ion batteries, ultrafine Fe3O4 nanocrystals uniformly encapsulated in two-dimensional (2D) carbon nanonetworks have been fabricated through thermolysis of a simple, low-cost iron(iii) acetylacetonate without any extra processes. Moreover, compared to the reported Fe3O4/carbon composites, the particle size of Fe3O4 is controllable and held down to ~3 nm. Benefitting from the synergistic effects of the excellent electroconductive carbon nanonetworks and uniform distribution of ultrafine Fe3O4 particles, the prepared 2D Fe3O4/carbon nanonetwork anode exhibits high reversible capacity, excellent rate capability and superior cyclability. A high capacity of 1534 mA h

  17. Synthesis of hierarchical Mg-doped Fe3O4 micro/nano materials for the decomposition of hexachlorobenzene.

    PubMed

    Su, Guijin; Liu, Yexuan; Huang, Linyan; Lu, Huijie; Liu, Sha; Li, Liewu; Zheng, Minghui

    2014-03-01

    An ethylene-glycol (EG) mediated self-assembly process was firstly developed to synthesize micrometer-sized nanostructured Mg-doped Fe3O4 composite oxides to decompose hexachlorobenzene (HCB) at 300°C. The synthesized samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy and inductively coupled plasma optical emission spectrometer. The morphology and composition of the composite oxide precursor were regulated by the molar ratio of the magnesium acetate and ferric nitrate as the reactants. Calcination of the precursor particles, prepared with different molar ratio of the metal salts, under a reducing nitrogen atmosphere, generated three kinds of Mg doped Fe3O4 composite oxide micro/nano materials. Their reactivity toward HCB decomposition was likely influenced by the material morphology and content of Mg dopants. Ball-like MgFe2O4-Fe3O4 composite oxide micro/nano material showed superior HCB dechlorination efficiencies when compared with pure Fe3O4 micro/nano material, prepared under similar experimental conditions, thus highlighting the benefits of doping Mg into Fe3O4 matrices. PMID:24290299

  18. A facile one-pot solvothermal method to produce superparamagnetic graphene-Fe3O4 nanocomposite and its application in the removal of dye from aqueous solution.

    PubMed

    Wu, Qiuhua; Feng, Cheng; Wang, Chun; Wang, Zhi

    2013-01-01

    A superparamagnetic graphene-Fe(3)O(4) nanocomposite (G/Fe(3)O(4)) was synthesized by a facile one-pot solvothermal method. The nanocomposite G/Fe(3)O(4) prepared by the new method was firstly used as an adsorbent to remove dye for water pollution remediation. In comparison with G/Fe(3)O(4) prepared by the in situ chemical coprecipitation, the newly prepared G/Fe(3)O(4) had a higher adsorption efficiency for the dye. The adsorption characteristics of the nanocomposite adsorbent were examined using the organic dye pararosaniline as the adsorbate. The adsorption kinetics, adsorption capacity of the adsorbent, and the effect of the adsorbent dosage and solution pH on the removal efficiency of pararosaniline were investigated. The adsorption capacity of G/Fe(3)O(4) for pararosaniline was evaluated using the Freundlich and Langmuir adsorption isotherm models. The G/Fe(3)O(4) hybrid composite can be easily manipulated in magnetic field for desired separation, leading to an easy removal of the dye from polluted water. The G/Fe(3)O(4) hybrid composite would have a great potential in removing organic dyes from polluted water. PMID:23010021

  19. Synthesis and characterization of Ag/Fe3O4 electromagnetic shielding particles

    NASA Astrophysics Data System (ADS)

    Li, Shichuan; Zhou, Zunning; Zhang, Tonglai; Jiang, Guotao; Su, Ruyi

    2014-05-01

    Ag/Fe3O4 nano-composites are synthesized by electroless silver plating technique and characterized by X-ray diffraction, scanning/transmission electron microscope, magnetic measurement equipment and vector network analyzer. They show the silver layer coated on the surface of the particles successfully, and which can enhance the dielectricity and permeability properties of the ferromagnetic particles. The dielectric loss values of the composites are more than 1.0 in the almost whole test frequency range and the imaginary part of permeability of Ag/Fe3O4 is higher than real part in 2-5 GHz. The value of Hc is increased to 165.2 Oe due to the extended relaxation time of magnetic domain deflection of the magnetic powders which covered by silver layer. And the calculated microwave loss is more than 20 dB in the whole frequency range. As a result, the Ag/Fe3O4 nano-composites are expected to be used as electromagnetic shielding particle material in multiband smoke agent.

  20. Enhanced high-frequency absorption of anisotropic Fe3O4/graphene nanocomposites.

    PubMed

    Yin, Yichao; Zeng, Min; Liu, Jue; Tang, Wukui; Dong, Hangrong; Xia, Ruozhou; Yu, Ronghai

    2016-01-01

    Anisotropic Fe3O4 nanoparticle and a series of its graphene composites have been successfully prepared as high-frequency absorbers. The crystal structure, morphology and magnetic property of the samples were detailed characterized through X-ray diffractometer (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The high-frequency absorbing performance of the composites is evaluated within 2.0-18.0 GHz. Combining reduced graphene oxide (RGO) to Fe3O4 helps to adjust the permittivity and permeability of the composite, balance the dielectric loss and magnetic loss, consequently improve the absorbing performance in view of the impedance matching characteristic. The optimal reflection loss of the pure Fe3O4 sample reaches -38.1 dB with a thickness of 1.7 mm, and it increases to -65.1 dB for the sample grafted with 3 wt.% RGO. The addition of proper content of RGO both improves the reflection loss and expands the absorbing bandwidth. This work not only opens a new method and an idea for tuning the electromagnetic properties and enhancing the capacity of high-efficient absorbers, but also broadens the application of such kinds of lightweight absorbing materials frameworks. PMID:27142260

  1. Enhanced high-frequency absorption of anisotropic Fe3O4/graphene nanocomposites

    NASA Astrophysics Data System (ADS)

    Yin, Yichao; Zeng, Min; Liu, Jue; Tang, Wukui; Dong, Hangrong; Xia, Ruozhou; Yu, Ronghai

    2016-05-01

    Anisotropic Fe3O4 nanoparticle and a series of its graphene composites have been successfully prepared as high-frequency absorbers. The crystal structure, morphology and magnetic property of the samples were detailed characterized through X-ray diffractometer (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The high-frequency absorbing performance of the composites is evaluated within 2.0–18.0 GHz. Combining reduced graphene oxide (RGO) to Fe3O4 helps to adjust the permittivity and permeability of the composite, balance the dielectric loss and magnetic loss, consequently improve the absorbing performance in view of the impedance matching characteristic. The optimal reflection loss of the pure Fe3O4 sample reaches ‑38.1 dB with a thickness of 1.7 mm, and it increases to ‑65.1 dB for the sample grafted with 3 wt.% RGO. The addition of proper content of RGO both improves the reflection loss and expands the absorbing bandwidth. This work not only opens a new method and an idea for tuning the electromagnetic properties and enhancing the capacity of high-efficient absorbers, but also broadens the application of such kinds of lightweight absorbing materials frameworks.

  2. Enhanced high-frequency absorption of anisotropic Fe3O4/graphene nanocomposites

    PubMed Central

    Yin, Yichao; Zeng, Min; Liu, Jue; Tang, Wukui; Dong, Hangrong; Xia, Ruozhou; Yu, Ronghai

    2016-01-01

    Anisotropic Fe3O4 nanoparticle and a series of its graphene composites have been successfully prepared as high-frequency absorbers. The crystal structure, morphology and magnetic property of the samples were detailed characterized through X-ray diffractometer (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The high-frequency absorbing performance of the composites is evaluated within 2.0–18.0 GHz. Combining reduced graphene oxide (RGO) to Fe3O4 helps to adjust the permittivity and permeability of the composite, balance the dielectric loss and magnetic loss, consequently improve the absorbing performance in view of the impedance matching characteristic. The optimal reflection loss of the pure Fe3O4 sample reaches −38.1 dB with a thickness of 1.7 mm, and it increases to −65.1 dB for the sample grafted with 3 wt.% RGO. The addition of proper content of RGO both improves the reflection loss and expands the absorbing bandwidth. This work not only opens a new method and an idea for tuning the electromagnetic properties and enhancing the capacity of high-efficient absorbers, but also broadens the application of such kinds of lightweight absorbing materials frameworks. PMID:27142260

  3. Electrostatic self-assembly of Fe 3O 4 nanoparticles on carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Liu, Yong; Jiang, Wei; Li, Song; Li, Fengsheng

    2009-06-01

    Carbon nanotubes (CNTs)-based magnetic nanocomposites can find numerous applications in nanotechnology, integrated functional system, and in medicine owing to their great potentialities. Herein, densely distributed magnetic Fe 3O 4 nanoparticles were successfully attached onto the convex surfaces of carbon nanotubes (CNTs) by an in situ polyol-medium solvothermal method via non-covalent functionalization of CNTs with cationic surfactant, cetyltrimethylammonium bromide (CTAB), and anionic polyelectrolyte, poly(sodium 4-styrenesulfonate) (PSS), through the polymer-wrapping technique, in which the negatively charged PSS-grafted CNTs can be used as primer for efficiently adsorption of positively metal ions on the basis of electrostatic attraction. X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis have been used to study the formation of Fe 3O 4/CNTs. The Fe 3O 4/CNTs nanocomposites were proved to be superparamagnetic with saturation magnetization of 43.5 emu g -1. A mechanism scheme was proposed to illustrate the formation process of the magnetic nanocomposites.

  4. Tailoring mechanical and antibacterial properties of chitosan/gelatin nanofiber membranes with Fe3O4 nanoparticles for potential wound dressing application

    NASA Astrophysics Data System (ADS)

    Cai, Ning; Li, Chao; Han, Chao; Luo, Xiaogang; Shen, Liang; Xue, Yanan; Yu, Faquan

    2016-04-01

    In this work, magnetic Fe3O4 nanoparticles (NPs) were utilized to improve the mechanical and antibacterial properties of chitosan (CS)/gelatin (GE) composite nanofiber membranes. Homogeneous Fe3O4/CS/GE nanofibers were electrospun successfully. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images confirmed the presence of well-dispersed Fe3O4 NPs in the composite nanofibers. Fourier transform infrared spectroscopy (FTIR) spectra revealed the effective interactions of Fe3O4 NPs to the composite matrix through hydrogen bonding. The improvement on the thermal stability of the Fe3O4/CS/GE was observed by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA), which is tightly correlated to strong filler-matrix adhesion. The incorporation of Fe3O4 NPs resulted in a substantial enhancement of mechanical properties. The optimum mechanical performance was demonstrated on 1 wt% Fe3O4/CS/GE nanofiber membranes, achieving 155% augment of Young's modulus, 128% increase of tensile strength, and 100% boost of toughness from CS/GE. The excellent mechanical enhancement can be explained by the effective dispersion of fillers and the filler-matrix interactions, which ensures the efficient load transfer from CS/GE matrix to Fe3O4 nanofillers. Moreover, zones of inhibition for Escherichia coli and Staphylococcus aureus expanded markedly with the supplement of Fe3O4 NPs. In all, nanofiber membranes made of Fe3O4/CS/GE composite with tailored mechanical and antibacterial properties appear a promising wound dressing material.

  5. Fe3 O4 Anisotropic Nanostructures in Hydrogels: Efficient Catalysts for the Rapid Removal of Organic Dyes from Wastewater.

    PubMed

    Gao, Yang; Hu, Chen; Zheng, Wen Jiang; Yang, Sen; Li, Fei; Sun, Shao Dong; Zrínyi, Miklós; Osada, Yoshihito; Yang, Zhi Mao; Chen, Yong Mei

    2016-07-01

    Fe3 O4 anisotropic nanostructures that exhibit excellent catalytic performance are rarely used to catalyze Fenton-like reactions because of the inevitable drawbacks resulting from traditional preparation methods. In this study, a facile, nontoxic, water-based approach is developed for directly regulating a series of anisotropic morphologies of Fe3 O4 nanostructures in a hydrogel matrix. In having the advantages of both the catalytic activity of Fe3 O4 and the adsorptive capacity of an anionic polymer network, the hybrid nanocomposites have the capability to effect the rapid removal of cationic dyes, such as methylene blue, from water samples. Perhaps more interestingly, hybrid nanocomposites loaded with Fe3 O4 nanorods exhibit the highest catalytic activity compared to those composed of nanoneedles and nanooctahedra, revealing the important role of nanostructure morphology. By means of scanning electrochemical microscopy, it is revealed that Fe3 O4 nanorods can efficiently catalyze H2 O2 decomposition and thus generate more free radicals ((.) OH, (.) HO2 ) for methylene blue degradation, which might account for their high catalytic activity. PMID:26955896

  6. The application of Fe3O4 nanoparticles in cancer research: a new strategy to inhibit drug resistance.

    PubMed

    Wang, Xuemei; Zhang, Renyun; Wu, Chunhui; Dai, Yongyuan; Song, Min; Gutmann, Sebastian; Gao, Feng; Lv, Gang; Li, Jingyuan; Li, Xiaomao; Guan, Zhiqun; Fu, Degang; Chen, Baoan

    2007-03-15

    Although much effort has been extended to the efficient cancer therapies, the drug resistance is still a major obstacle in cancer chemotherapeutic treatments. Almost 90% of the cancer therapy failure is caused by the relative problems. Recently, the application of drug coated polymer nanospheres and nanoparticles to inhibit the related drug resistance has attracted much attention. In this report, we have explored a novel strategy to inhibit the multidrug resistance of the targeted tumor cells by combining the unique properties of tetraheptylammonium capped Fe(3)O(4) magnetic nanoparticles with the drug accumulation of anticancer drug daunorubicin. Our results of confocal fluorescence and atomic force microscopy (AFM) as well as electrochemical studies demonstrate the remarkable synergistic effect of Fe(3)O(4) nanoparticles on drug uptake of daunorubicin in leukemia K562 cells. These observations indicate that the interaction between the magnetic nanoparticles Fe(3)O(4) and biologically active molecules on the membrane of leukemia cell lines may contribute to their beneficial effect on cellular uptake so that the synergistic enhanced effect of magnetic nanoparticles Fe(3)O(4) on drug uptake of drug resistance leukemia K562 cells could be observed upon application of the Fe(3)O(4) nanoparticles. PMID:17072850

  7. A facile synthesis of superparamagnetic Fe3O4 supraparticles@MIL-100(Fe) core-shell nanostructures: Preparation, characterization and biocompatibility.

    PubMed

    Yu, Shoushan; Wan, Jiaqi; Chen, Kezheng

    2016-01-01

    Superparamagnetic Fe3O4 supraparticles@MIL-100(Fe) core-shell nanostructure microspheres were successfully constructed by a facile step-by-step method. The polyacrylate formed in situ during the process of the preparation of Fe3O4 supraparticles not only acted as a stabilizer on the Fe3O4 nanoparticles surface, but also played a crucial role as a "bridge" in the initial stage of the framework components selectively assembly on the Fe3O4 supraparticle surfaces. The structure and composition of the obtained microspheres were characterized by SEM, TEM, DLS, XRD, FTIR, and TG analysis. The MPMS results revealed that the introduction of the MOF shells can inhibit the interplay among the neighboring Fe3O4 supraparticles while an external magnetic field applied. The well-dispersed microspheres are biocompatible, which endow the microspheres great potential in drug targeting applications with enhanced efficiency. PMID:26397925

  8. Preparation of a new Fe3O4/starch-g-polyester nanocomposite hydrogel and a study on swelling and drug delivery properties.

    PubMed

    Hamidian, Hooshang; Tavakoli, Tayebeh

    2016-06-25

    A new Fe3O4/starch-g-poly(ethylene phthalate) hydrogel nanocomposite was prepared using poly(ethylene phthalate) grafted onto starch as a biopolymer. The nanocomposite was characterized by FT-IR, XRD, DLS and SEM. FT-IR spectra proved that polyester had been grafted onto starch in a copolymerization reaction. XRD spectra confirmed the synthesis of the nanocomposite and the average size of the particles. SEM observations showed that Fe3O4 nanoparticles have been uniformly dispersed in a polymeric matrix. Swelling and drug delivery properties of Fe3O4/starch-g-poly(ethylene phthalate) nanocomposite were studied. It was confirmed that Fe3O4/starch-g-polyester nanocomposite with 0.01M concentrations of FeCl2 and 0.005M of FeCl3 is the most appropriate for swelling and the composite without Fe3O4 nanoparticles is optimum for drug delivery. PMID:27083803

  9. Schottky barrier effect on the electrical properties of Fe3O4/ZnO and Fe3O4/Nb : SrTiO3 heterostructures

    NASA Astrophysics Data System (ADS)

    Yang, Kiwon; Kim, D. H.; Dho, Joonghoe

    2011-09-01

    The current-voltage (I-V) characteristics of Fe3O4/Nb-doped SrTiO3(Nb : STO) and Fe3O4/ZnO junctions prepared by pulsed laser deposition were investigated as a function of temperature. The rectifying behaviour was more distinctive in Fe3O4/Nb : STO than in the Fe3O4/ZnO. Contrary to Fe3O4/Nb : STO, remarkably, the current flow in Fe3O4/ZnO was slightly larger for negative bias voltages than for positive bias voltages. The threshold voltage in Fe3O4/Nb : STO dramatically shifted to a higher voltage by decreasing the temperature, and hysteresis behaviour with a cyclic voltage sweep appeared below 120 K. Upon cooling, the rectifying behaviour in Fe3O4/ZnO gradually disappeared within the measurement range. The observed difference between Fe3O4/Nb : STO and Fe3O4/ZnO could be explained by the shape and height of the Schottky barrier which was determined by the relative magnitude of the work functions of the two contact materials. The formation of the Schottky barrier presumably resulted from an upward shift of the interface band in Fe3O4/Nb : STO, while a little downward shift of the interface band occurred in Fe3O4/ZnO. In addition, Al-doping into ZnO induced a complete disappearance of the Schottky barrier in the Fe3O4/Al-doped ZnO junction.

  10. Coupling Hollow Fe3O4-Fe Nanoparticles with Graphene Sheets for High-Performance Electromagnetic Wave Absorbing Material.

    PubMed

    Qu, Bin; Zhu, Chunling; Li, Chunyan; Zhang, Xitian; Chen, Yujin

    2016-02-17

    We developed a strategy for coupling hollow Fe3O4-Fe nanoparticles with graphene sheets for high-performance electromagnetic wave absorbing material. The hollow Fe3O4-Fe nanoparticles with average diameter and shell thickness of 20 and 8 nm, respectively, were uniformly anchored on the graphene sheets without obvious aggregation. The minimal reflection loss RL values of the composite could reach -30 dB at the absorber thickness ranging from 2.0 to 5.0 mm, greatly superior to the solid Fe3O4-Fe/G composite and most magnetic EM wave absorbing materials recently reported. Moreover, the addition amount of the composite into paraffin matrix was only 18 wt %. PMID:26829291

  11. Synthesis and characterization of Fe3O4-TiO2 core-shell nanoparticles

    NASA Astrophysics Data System (ADS)

    Stefan, M.; Pana, O.; Leostean, C.; Bele, C.; Silipas, D.; Senila, M.; Gautron, E.

    2014-09-01

    Composite core-shell nanoparticles may have morpho-structural, magnetic, and optical (photoluminescence (PL)) properties different from each of the components considered separately. The properties of Fe3O4-TiO2 nanoparticles can be controlled by adjusting the titania amount (shell thinness). Core-shell nanoparticles were prepared by seed mediated growth of semiconductor (TiO2) through a modified sol-gel process onto preformed magnetite (Fe3O4) cores resulted from the co-precipitation method. The structure and morphology of samples were characterized by X-ray diffraction, transmission electron microscopy (TEM), and high resolution-TEM respectively. X-ray photoelectron spectroscopy was correlated with ICP-AES. Magnetic measurements, optical absorption spectra, as well as PL spectroscopy indicate the presence of a charge/spin transfer from the conduction band of magnetite into the band gap of titania nanocrystals. The process modifies both Fe3O4 and TiO2 magnetic and optical properties, respectively.

  12. Magnetic nanoparticle of Fe3O4 and 5-bromotetrandrin interact synergistically to induce apoptosis by daunorubicin in leukemia cells

    PubMed Central

    Chen, Baoan; Cheng, Jian; Shen, Mingfang; Gao, Feng; Xu, Wenlin; Shen, Huilin; Ding, Jiahua; Gao, Chong; Sun, Qian; Sun, Xinchen; Cheng, Hongyan; Li, Guohong; Chen, Wenji; Chen, Ningna; Liu, Lijie; Li, Xiaomao; Wang, Xuemei

    2009-01-01

    Apoptosis is a common pathway that finally mediated the killing functions of anticancer drugs, which is an important cause of multidrug resistance (MDR). The aim of this study was to investigate the potential benefit of combination therapy with magnetic nanoparticle of Fe3O4 (MNP(Fe3O4)) and 5-bromotetrandrin (BrTet). Analysis of the apoptosis percentage showed that combination of daunorubicin (DNR) with either MNP(Fe3O4) or BrTet exerted a potent cytotoxic effect on K562/A02 cells, while MNP(Fe3O4) and BrTet cotreatment can synergistically enhance DNR-induced apoptosis. Importantly, we confirmed that the distinct synergism effect of that composite on reverse multidrug resistance may owe to the regulation of various proliferative and antiapoptotic gene products, including P53 and caspase-3. Thus our in vitro data strongly suggests a potential clinical application of MNP(Fe3O4) and BrTet combination on CML. PMID:19421371

  13. Synthesis and characterization of Fe3O4 and ZnO nanocomposites by the sol-gelmethod

    NASA Astrophysics Data System (ADS)

    Hasanpour, A.; Niyaifar, M.; Asan, M.; Amighian, J.

    2013-05-01

    In this work, magnetite (Fe3O4) nanoparticles were first prepared from ferric nitrate (Fe(NO3)3 9H2O) and ethylene glycol (C2H6O2) in inert atmosphere using the sol-gel method. In the next stage, composite nanopowders of Fe3O4-ZnO were obtained from zinc acetate and diethanolamine via the sol-gel method. The precursor was first dried and then annealed in vacuum furnace at different temperatures. The X-ray diffraction results confirm the formation of Fe3O4-ZnO nanocomposites. Transmission Electron Microscopy showed that the prepared powders are made of the spherical shape particles with an average size of about 40 nm. Fourier transform infrared spectra for the characteristic absorption of Zn-O bond is at 453.1 cm-1and of Fe-O bond is 540.2 cm-1. Results of vibrating sample magnetometer reveal that the Fe3O4 nanoparticles are superparamagnetic, whereas in the form of Fe3O4-ZnO nanocomposites arenot.

  14. Large tunneling magnetoresistance in octahedral Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Mitra, Arijit; Barick, Barun; Mohapatra, Jeotikanta; Sharma, H.; Meena, S. S.; Aslam, M.

    2016-05-01

    We have observed large tunneling Magnetoresistance (TMR) in amine functionalized octahedral nanoparticle assemblies. Amine monolayer on the surface of nanoparticles acts as an insulating barrier between the semimetal Fe3O4 nanoparticles and provides multiple tunnel junctions where inter-granular tunneling is plausible. The tunneling magnetoresistance recorded at room temperature is 38% which increases to 69% at 180 K. When the temperature drops below 150 K, coulomb staircase is observed in the current versus voltage characteristics as the charging energy exceeds the thermal energy. A similar study is also carried out with spherical nanoparticles. A 24% TMR is recorded at room temperature which increases to 41% at 180 K for spherical particles. Mössbauer spectra reveal better stoichiometry for octahedral particles which is attainable due to lesser surface disorder and strong amine coupling at the <111> facets of octahedral Fe3O4 nanoparticles. Less stoichiometric defect in octahedral nanoparticles leads to a higher value of spin polarization and therefore larger TMR in octahedral nanoparticles.

  15. Antifungal activity of multifunctional Fe 3O 4-Ag nanocolloids

    NASA Astrophysics Data System (ADS)

    Chudasama, Bhupendra; Vala, Anjana K.; Andhariya, Nidhi; Upadhyay, R. V.; Mehta, R. V.

    2011-05-01

    In recent years, rapid increase has been observed in the population of microbes that are resistant to conventionally used antibiotics. Antifungal drug therapy is no exception and now resistance to many of the antifungal agents in use has emerged. Therefore, there is an inevitable and urgent medical need for antibiotics with novel antimicrobial mechanisms. Aspergillus glaucus is the potential cause of fatal brain infections and hypersensitivity pneumonitis in immunocompromised patients and leads to death despite aggressive multidrug antifungal therapy. In the present article, we describe the antifungal activity of multifunctional core-shell Fe 3O 4-Ag nanocolloids against A. glaucus isolates. Controlled experiments are also carried out with Ag nanocolloids in order to understand the role of core (Fe 3O 4) in the antifungal action. The minimum inhibitory concentration (MIC) of nanocolloids is determined by the micro-dilution method. MIC of A. glaucus is 2000 μg/mL. The result is quite promising and requires further investigations in order to develop a treatment methodology against this death causing fungus in immunocompromised patients.

  16. Microbial synthesis of Pd/Fe3O4, Au/Fe3O4 and PdAu/Fe3O4 nanocomposites for catalytic reduction of nitroaromatic compounds

    PubMed Central

    Tuo, Ya; Liu, Guangfei; Dong, Bin; Zhou, Jiti; Wang, Aijie; Wang, Jing; Jin, Ruofei; Lv, Hong; Dou, Zeou; Huang, Wenyu

    2015-01-01

    Magnetically recoverable noble metal nanoparticles are promising catalysts for chemical reactions. However, the chemical synthesis of these nanocatalysts generally causes environmental concern due to usage of toxic chemicals under extreme conditions. Here, Pd/Fe3O4, Au/Fe3O4 and PdAu/Fe3O4 nanocomposites are biosynthesized under ambient and physiological conditions by Shewanella oneidensis MR-1. Microbial cells firstly transform akaganeite into magnetite, which then serves as support for the further synthesis of Pd, Au and PdAu nanoparticles from respective precursor salts. Surface-bound cellular components and exopolysaccharides not only function as shape-directing agent to convert some Fe3O4 nanoparticles to nanorods, but also participate in the formation of PdAu alloy nanoparticles on magnetite. All these three kinds of magnetic nanocomposites can catalyze the reduction of 4-nitrophenol and some other nitroaromatic compounds by NaBH4. PdAu/Fe3O4 demonstrates higher catalytic activity than Pd/Fe3O4 and Au/Fe3O4. Moreover, the magnetic nanocomposites can be easily recovered through magnetic decantation after catalysis reaction. PdAu/Fe3O4 can be reused in at least eight successive cycles of 4-nitrophenol reduction. The biosynthesis approach presented here does not require harmful agents or rigorous conditions and thus provides facile and environmentally benign choice for the preparation of magnetic noble metal nanocatalysts. PMID:26310728

  17. Fe3O4@B-MCM-41: A new magnetically recoverable nanostructured catalyst for the synthesis of polyhydroquinolines

    NASA Astrophysics Data System (ADS)

    Abdollahi-Alibeik, Mohammad; Rezaeipoor-Anari, Ali

    2016-01-01

    Boron modified MCM-41 with magnetite core (Fe3O4@B-MCM-41) as a new magnetically recoverable heterogeneous catalyst was prepared and characterized by SEM, TEM, BET, XRD, VSM and FT-IR techniques. The catalytic activity of Fe3O4@B-MCM-41 was investigated in the four-component reaction of aldehyde, dimedone, active methylene compounds and ammonium acetate for the synthesis of polyhydroquinolines. According to optimization and characterization results the catalyst with Si:B:Fe3O4 mole composition of 40:4:1 has the best activity. The catalyst could be recovered easily by external magnet and has excellent reusability many times without significant decrease of activity.

  18. Uniform Fe3O4 coating on flower-like ZnO nanostructures by atomic layer deposition for electromagnetic wave absorption.

    PubMed

    Wan, Gengping; Wang, Guizhen; Huang, Xianqin; Zhao, Haonan; Li, Xinyue; Wang, Kan; Yu, Lei; Peng, Xiange; Qin, Yong

    2015-11-21

    An elegant atomic layer deposition (ALD) method has been employed for controllable preparation of a uniform Fe3O4-coated ZnO (ZnO@Fe3O4) core-shell flower-like nanostructure. The Fe3O4 coating thickness of the ZnO@Fe3O4 nanostructure can be tuned by varying the cycle number of ALD Fe2O3. When serving as additives for microwave absorption, the ZnO@Fe3O4-paraffin composites exhibit a higher absorption capacity than the ZnO-paraffin composites. For ZnO@500-Fe3O4, the effective absorption bandwidth below -10 dB can reach 5.2 GHz and the RL values below -20 dB also cover a wide frequency range of 11.6-14.2 GHz when the coating thickness is 2.3 mm, suggesting its potential application in the treatment of the electromagnetic pollution problem. On the basis of experimental observations, a mechanism has been proposed to understand the enhanced microwave absorption properties of the ZnO@Fe3O4 composites. PMID:26458422

  19. Preparation of the chitosan grafted poly (quaternary ammonium)/Fe3O4 nanoparticles and its adsorption performance for food yellow 3.

    PubMed

    Yu, Chen; Geng, Jianqiang; Zhuang, Yunxia; Zhao, Jian; Chu, Liqiu; Luo, Xiaoxuan; Zhao, Ying; Guo, Yanwen

    2016-11-01

    Chitosan and its derivatives can be used to modify magnetic materials to promote the adsorption properties of the magnetic materials and avoid the weakness of chitosan and its derivatives. In the present study, chitosan grafted poly(trimethyl allyl ammonium chloride) (CTS-g-PTMAAC) was prepared by graft copolymerization; then it was coated on the surfaces of the sodium citrate coated Fe3O4 nanoparticles (SC-Fe3O4) to prepare a novel composite CTS-g-PTMAAC/SC-Fe3O4 magnetic nanoparticles, with which possesses abundant surface positive charges. The structure and properties of the CTS-g-PTMAAC/SC-Fe3O4 composite magnetic nanoparticles were characterized by FTIR, TEM, VSM, and zeta potential. The dye adsorption characteristics of the CTS-g-PTMAAC/SC-Fe3O4 nanoparticles were determined using the food yellow 3 aqueous solutions as a model food effluent. Effect of pH of the dye solution on the adsorption of food yellow 3 was determined and compared with N-2-hydroxylpropyl trimethyl ammonium chloride chitosan coated sodium citrate-Fe3O4 (CTS-g-HTCC/SC-Fe3O4) composite magnetic nanoparticles. The adsorption kinetics, adsorption isotherms, adsorption thermodynamics, and desorption and reusability of the magnetic nanoparticles were investigated. PMID:27516279

  20. The Influence of Active Carbon Supports Toward the Electrocatalytic Behavior of Fe3O4 Nanoparticles for the Extended Energy Generation of Mediatorless Microbial Fuel Cells.

    PubMed

    Park, In Ho; Kim, Pil; Gnana Kumar, G; Nahm, Kee Suk

    2016-08-01

    Magnetite (Fe3O4) nanoparticles anchored over the different active carbon supports were developed by a simple wet solution method. The developed nanostructures were magnetically self-assembled over the electrode surface and exploited as anode catalysts in mediatorless microbial fuel cells (MFC). The morphological characterizations revealed that 3∼8-nm-sized Fe3O4 nanoparticles were homogeneously anchored over the different carbon matrices and the obtained diffraction patterns ensured the cubic inverse spinel structure of prepared Fe3O4 nanoparticles. The morphology, size, and structure of Fe3O4 nanoparticles anchored over the different active carbon supports were maintained identical, and the influence of active carbon support toward the effectual MFC performances was evaluated under various electrochemical regimes and conditions by using Escherichia coli as a catalytic microorganism. The electrochemical characterizations revealed that carbon nanotube (CNT)-supported Fe3O4 nanoparticles exhibited lower charge transfer resistance and high coulombic efficiency in comparison with the graphene and graphite nanofiber-supported composites. Among the studied anode catalysts, Fe3O4/CNT composite exhibited the maximum MFC power density of 865 mW m(-2) associated with excellent durability performances, owing to the specific interaction exerted between the microorganisms and the Fe3O4/CNT composite. Thus, the binder-free electrode modification process, mediatorless environment, rapid electron transfer kinetics, high power generation, and long durability performances achieved for the developed system paved futuristic dimensions for the high performance MFCs. PMID:27038051

  1. One-pot green synthesis of reduced graphene oxide (RGO)/Fe3O4 nanocomposites and its catalytic activity toward methylene blue dye degradation.

    PubMed

    Vinothkannan, M; Karthikeyan, C; Gnana kumar, G; Kim, Ae Rhan; Yoo, Dong Jin

    2015-02-01

    The reduced graphene oxide (RGO)/Fe3O4 nanocomposites were synthesized through a facile one-pot green synthesis by using solanum trilobatum extract as a reducing agent. Spherical shaped Fe3O4 nanoparticles with the diameter of 18 nm were uniformly anchored over the RGO matrix and the existence of fcc structured Fe3O4 nanoparticles over the RGO matrix was ensured from X-ray diffraction patterns. The amide functional groups exist in the solanum trilobatum extract is directly responsible for the reduction of Fe(3+) ions and GO. The thermal stability of GO was increased by the removal of hydrophilic functional groups via solanum trilobatum extract and was further promoted by the ceramic Fe3O4 nanoparticles. The ID/IG ratio of RGO/Fe3O4 was increased over GO, indicating the extended number of structural defects and disorders in the RGO/Fe3O4 composite. The catalytic efficiency of prepared nanostructures toward methylene blue (MB) dye degradation mediated through the electron transfer process of BH4(-) ions was studied in detail. The π-π stacking, hydrogen bonding and electrostatic interaction exerted between the RGO/Fe3O4 composite and methylene blue, increased the adsorption efficiency of dye molecules and the large surface area and extended number of active sites completely degraded the MB dye within 12 min. PMID:25311523

  2. One-pot green synthesis of reduced graphene oxide (RGO)/Fe3O4 nanocomposites and its catalytic activity toward methylene blue dye degradation

    NASA Astrophysics Data System (ADS)

    Vinothkannan, M.; Karthikeyan, C.; Gnana kumar, G.; Kim, Ae Rhan; Yoo, Dong Jin

    2015-02-01

    The reduced graphene oxide (RGO)/Fe3O4 nanocomposites were synthesized through a facile one-pot green synthesis by using solanum trilobatum extract as a reducing agent. Spherical shaped Fe3O4 nanoparticles with the diameter of 18 nm were uniformly anchored over the RGO matrix and the existence of fcc structured Fe3O4 nanoparticles over the RGO matrix was ensured from X-ray diffraction patterns. The amide functional groups exist in the solanum trilobatum extract is directly responsible for the reduction of Fe3+ ions and GO. The thermal stability of GO was increased by the removal of hydrophilic functional groups via solanum trilobatum extract and was further promoted by the ceramic Fe3O4 nanoparticles. The ID/IG ratio of RGO/Fe3O4 was increased over GO, indicating the extended number of structural defects and disorders in the RGO/Fe3O4 composite. The catalytic efficiency of prepared nanostructures toward methylene blue (MB) dye degradation mediated through the electron transfer process of BH4- ions was studied in detail. The π-π stacking, hydrogen bonding and electrostatic interaction exerted between the RGO/Fe3O4 composite and methylene blue, increased the adsorption efficiency of dye molecules and the large surface area and extended number of active sites completely degraded the MB dye within 12 min.

  3. Synthesis of Fe3O4 and Pt nanoparticles on reduced graphene oxide and their use as a recyclable catalyst.

    PubMed

    Wu, Shixin; He, Qiyuan; Zhou, Chunmei; Qi, Xiaoying; Huang, Xiao; Yin, Zongyou; Yang, Yanhui; Zhang, Hua

    2012-04-01

    A bifunctional Fe(3)O(4)-Pt/reduced graphene oxide (rGO) composite, i.e. Fe(3)O(4) nanoparticles (~4.8 nm in size) and Pt nanoparticles (~5 nm in size) loaded on a rGO surface, has been synthesized. It shows great catalytic performance for the reduction of methylene blue. Recycling of the composite can be achieved by simply applying an external magnetic field. In addition, the Fe(3)O(4)-Pt/rGO composite exhibits a higher catalytic activity and selectivity for aqueous-phase aerobic oxidation of benzyl alcohol than does the FeO(x)-Pt on carbon nanotubes (i.e. FeO(x)-Pt/CNT composite). Moreover, the approach for the synthesis of Fe(3)O(4)-Pt/rGO composite is simple, and can be widely employed to produce other rGO-based composites with special properties. Our work indicates that the rGO-based bifunctional composite has great potential for practical applications in various fields, such as catalytic reaction, electrochemical sensing, clean energy, etc. PMID:22388949

  4. Core-shell SiO2 -coated Fe3 O4 with a surface molecularly imprinted polymer coating of folic acid and its applicable magnetic solid-phase extraction prior to determination of folates in tomatoes.

    PubMed

    Areerob, Yonrapach; Sricharoen, Phitchan; Limchoowong, Nunticha; Chanthai, Saksit

    2016-08-01

    A novel core-shell magnetic surface molecularly imprinted polymer with folic acid as a template was successfully synthesized by the sol-gel method. To generate Lewis acid sites in the silica matrix for the interaction of the metal coordinate with the template, 3-aminopropyltriethoxysilane was used as a functional monomer, tetraethyl orthosilicate as a cross-linker, and aluminum ions as a dopant. The magnetite encapsulated by the silica shell plays an important role as a magnetic-coated polymer. The synthesized product was characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and FTIR and UV/Vis spectroscopy. The powder X-ray diffraction patterns, FTIR and UV/Vis spectra confirmed the characteristics of the as-prepared silica coated magnetite and folic acid molecularly imprinted polymer. It was successfully applied for magnetic solid-phase extraction prior to the determination of folates in tomato samples using high-performance liquid chromatography with photodiode array detection. The detection limit of the proposed method was 1.67 μg/L, and results were satisfactory, with a relative standard deviation of < 3.94%. PMID:27296679

  5. Electrochemical sensing behaviour of Ni doped Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Suresh, R.; Giribabu, K.; Manigandan, R.; Vijayalakshmi, L.; Stephen, A.; Narayanan, V.

    2014-01-01

    Ni doped Fe3O4 nanoparticles were synthesized by simple hydrothermal method. The prepared nanomaterials were characterized by X-ray diffraction analysis, DRS-UV-Visible spectroscopy and field emission scanning electron microscopy. The XRD confirms the phase purity of the synthesized Ni doped Fe3O4 nanoparticles. The optical property of Ni doped Fe3O4 nanoparticles were studied by DRS UV-Visible analysis. The electrochemical sensing property of pure and Ni doped Fe3O4 nanoparticles were examined using uric acid as an analyte. The obtained results indicated that the Ni doped Fe3O4 nanoparticles exhibited higher electrocatalytic activity towards uric acid.

  6. In situ preparation of monodispersed Ag/polyaniline/Fe3O4 nanoparticles via heterogeneous nucleation

    PubMed Central

    2013-01-01

    Acrylic acid and styrene were polymerized onto monodispersed Fe3O4 nanoparticles using a grafting copolymerization method. Aniline molecules were then bonded onto the Fe3O4 nanoparticles by electrostatic self-assembly and further polymerized to obtain uniform polyaniline/Fe3O4 (PANI/Fe3O4) nanoparticles (approximately 35 nm). Finally, monodispersed Ag/PANI/Fe3O4 nanoparticles were prepared by an in situ reduction reaction between emeraldine PANI and silver nitrate. Fourier transform infrared and UV-visible spectrometers and a transmission electron microscope were used to characterize both the chemical structure and the morphology of the resulting nanoparticles. PMID:23819820

  7. Rapid degradation of methylene blue in a novel heterogeneous Fe3O4 @rGO@TiO2-catalyzed photo-Fenton system

    PubMed Central

    Yang, Xiaoling; Chen, Wei; Huang, Jianfei; Zhou, Ying; Zhu, Yihua; Li, Chunzhong

    2015-01-01

    Herein, a ternary nanocomposite with TiO2 nanoparticles anchored on reduced graphene oxide (rGO)-encapsulated Fe3O4 spheres (Fe3O4@rGO@TiO2) is presented as a high efficient heterogeneous catalyst for photo-Fenton degradation of recalcitrant pollutants under neutral pH. Fe3O4@rGO@TiO2 was synthesized by depositing TiO2 nanoparticles on the surface of the Fe3O4 spheres wrapped by graphene oxide (GO) which was obtained by an electrostatic layer-by-layer method. This as-prepared catalyst reflected good ferromagnetism and superior stability which makes it convenient to be separated and recycled. Due to the synergic effects between the different components composed the catalyst, swift reduction of Fe3+ can be achieved to regenerate Fe2+. Fe3O4@rGO@TiO2 exhibited enhancing catalytic activity for the degradation of azo-dyes compared with Fe3O4, Fe3O4@SiO2@TiO2 or SiO2@rGO@TiO2, further conforming the rapid redox reaction between Fe2+ and Fe3+. All these merits indicate that the composite catalyst possesses great potential for visible-light driven destruction of organic compounds. PMID:26000975

  8. Rapid degradation of methylene blue in a novel heterogeneous Fe3O4 @rGO@TiO2-catalyzed photo-Fenton system

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoling; Chen, Wei; Huang, Jianfei; Zhou, Ying; Zhu, Yihua; Li, Chunzhong

    2015-05-01

    Herein, a ternary nanocomposite with TiO2 nanoparticles anchored on reduced graphene oxide (rGO)-encapsulated Fe3O4 spheres (Fe3O4@rGO@TiO2) is presented as a high efficient heterogeneous catalyst for photo-Fenton degradation of recalcitrant pollutants under neutral pH. Fe3O4@rGO@TiO2 was synthesized by depositing TiO2 nanoparticles on the surface of the Fe3O4 spheres wrapped by graphene oxide (GO) which was obtained by an electrostatic layer-by-layer method. This as-prepared catalyst reflected good ferromagnetism and superior stability which makes it convenient to be separated and recycled. Due to the synergic effects between the different components composed the catalyst, swift reduction of Fe3+ can be achieved to regenerate Fe2+. Fe3O4@rGO@TiO2 exhibited enhancing catalytic activity for the degradation of azo-dyes compared with Fe3O4, Fe3O4@SiO2@TiO2 or SiO2@rGO@TiO2, further conforming the rapid redox reaction between Fe2+ and Fe3+. All these merits indicate that the composite catalyst possesses great potential for visible-light driven destruction of organic compounds.

  9. One-step synthesis of novel PANI-Fe3O4@ZnO core-shell microspheres: An efficient photocatalyst under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyuan; Wu, Jianning; Meng, Guihua; Guo, Xuhong; Liu, Chang; Liu, Zhiyong

    2016-03-01

    For the first time, novel multifunctional superparamagnetic PANI-Fe3O4@ZnO core-shell composite photocatalysts with different PANI: ZnO ratios were synthesized by Pickering emulsion route in one step in the presence of ZnO nanoparticles. PANI-Fe3O4@ZnO core-shell microspheres consist of PANI core which embedded with Fe3O4-OA (oleic acid modified Fe3O4) nanoparticles and tunable ZnO shell thickness. The resulting samples were thoroughly studied by using X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). The catalytic activity of the as-prepared PANI-Fe3O4@ZnO core-shell microspheres is investigated by the degradation of MB under visible light irradiation. As expected, the as prepared PANI-Fe3O4@ZnO photocatalysts exhibit highly enhanced photocatalytic activities in the degradation of MB under visible light irradiation owing to fast separation of photo-generated electron-hole pairs. Significantly, the PANI-Fe3O4@ZnO catalysts can be separated from the reaction media by applying an external magnet, and can be reused for seven cycles without change in stability and degradation efficiency.

  10. Rapid degradation of methylene blue in a novel heterogeneous Fe3O4 @rGO@TiO2-catalyzed photo-Fenton system.

    PubMed

    Yang, Xiaoling; Chen, Wei; Huang, Jianfei; Zhou, Ying; Zhu, Yihua; Li, Chunzhong

    2015-01-01

    Herein, a ternary nanocomposite with TiO2 nanoparticles anchored on reduced graphene oxide (rGO)-encapsulated Fe3O4 spheres (Fe3O4@rGO@TiO2) is presented as a high efficient heterogeneous catalyst for photo-Fenton degradation of recalcitrant pollutants under neutral pH. Fe3O4@rGO@TiO2 was synthesized by depositing TiO2 nanoparticles on the surface of the Fe3O4 spheres wrapped by graphene oxide (GO) which was obtained by an electrostatic layer-by-layer method. This as-prepared catalyst reflected good ferromagnetism and superior stability which makes it convenient to be separated and recycled. Due to the synergic effects between the different components composed the catalyst, swift reduction of Fe(3+) can be achieved to regenerate Fe(2+). Fe3O4@rGO@TiO2 exhibited enhancing catalytic activity for the degradation of azo-dyes compared with Fe3O4, Fe3O4@SiO2@TiO2 or SiO2@rGO@TiO2, further conforming the rapid redox reaction between Fe(2+) and Fe(3+). All these merits indicate that the composite catalyst possesses great potential for visible-light driven destruction of organic compounds. PMID:26000975

  11. Investigation of electric field effect on the third order nonlinear optical properties of Fe3O4 nanoparticles-doped nematic liquid crystal

    NASA Astrophysics Data System (ADS)

    Dehghani, Z.; Saievar Iranizad, E.; Nadafan, M.

    2015-01-01

    Third order nonlinearity of Fe3O4 nanoparticles (NPs) doped in nematic liquid crystals (NLCs) was evaluated due to laser induced self-phase modulation. The influence of electric field on the nonlinear optical responses of the NLCs doped with Fe3O4 NPs was considered in different voltages. The measurements were performed for two commonly initial alignments (homogeneous and homeotropic) with different small compositional percentages of magnetic NPs. The experimental results show that the homogenous- aligned cell was considerably affected on the applied electric field while the nonlinearity of homeotropic-aligned NLCs with the Fe3O4 NPs did not approximately change in the presence of electric field.

  12. Chitosan and O-carboxymethyl chitosan modified Fe3O4 for hyperthermic treatment

    NASA Astrophysics Data System (ADS)

    Thu Trang Mai, Thi; Thu Ha, Phuong; Pham, Hong Nam; Thu Huong Le, Thi; Linh Pham, Hoai; Bich Hoa Phan, Thi; Tran, Dai Lam; Phuc Nguyen, Xuan

    2012-03-01

    In this study magnetic fluids were manufactured by the adsorption of chitosan (CS) and O-carboxymethyl chitosan (OCMCS) on Fe3O4 nanoparticles to be used as hyperthermic thermoseeds. Fe3O4 particles were characterized by physico-chemical methods such as: thermogravimetry analysis (TGA), x-ray diffraction (XRD), Raman spectrum, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). The SEM images and XRD patterns showed that the synthesized Fe3O4 nanoparticles were of single phase and spherical shape with 10–15 nm in diameter. The VSM measurements showed that Fe3O4 particles were superparamagnetic with saturation magnetization of 70 emu g‑1. The adsorbed layers of CS and OCMCS on the magnetite surface (Fe3O4/CS) and (Fe3O4/OCMCS) were confirmed by FTIR, Raman spectra and SEM. In the ac magnetic field of 80 Oe and 236 kHz, the saturation heating temperatures of the sample Fe3O4/CS and Fe3O4/OCMCS were 100 and 98 °C, respectively. At the same concentration of Fe3O4 nanoparticles in suspension, the two magnetic fluids exhibited quite high heating capacity, with different behaviors of concentration dependence. The Fe3O4/CS and Fe3O4/OCMCS nanoparticles would serve as good thermoseeds for localized hyperthermia treatment of cancers.

  13. Exchange spring magnetic behavior in BaFe12O19/Fe3O4 nanocomposites

    NASA Astrophysics Data System (ADS)

    Remya, K. P.; Prabhu, D.; Amirthapandian, S.; Viswanathan, C.; Ponpandian, N.

    2016-05-01

    We report the investigation on exchange spring coupling behavior of BaFe12O19/Fe3O4 nanocomposite synthesized by simple mixing followed by heat treatment of individual ferrites. Morphologically tuned, well crystalline hard and soft ferrites were synthesized by simple chemical method and the phase composition, crystallinity, surface morphology and magnetic properties of the as prepared ferrites as well as the nanocomposites were studied by using XRD, FESEM and VSM respectively. Exchange coupling behavior is observed in the nanocomposite samples heated at 600 °C with simultaneous enhancements of (BH)max and remanence.

  14. Recent advances in the synthesis of Fe3O4@AU core/shell nanoparticles

    NASA Astrophysics Data System (ADS)

    Salihov, Sergei V.; Ivanenkov, Yan A.; Krechetov, Sergei P.; Veselov, Mark S.; Sviridenkova, Natalia V.; Savchenko, Alexander G.; Klyachko, Natalya L.; Golovin, Yury I.; Chufarova, Nina V.; Beloglazkina, Elena K.; Majouga, Alexander G.

    2015-11-01

    Fe3O4@Au core/shell nanoparticles have unique magnetic and optical properties. These nanoparticles are used for biomedical applications, such as magnetic resonance imaging, photothermal therapy, controlled drug delivery, protein separation, biosensors, DNA detection, and immunosensors. In this review, recent methods for the synthesis of core/shell nanoparticles are discussed. We divided all of the synthetic methods in two groups: methods of synthesis of bi-layer structures and methods of synthesis of multilayer composite structures. The latter methods have a layer of "glue" material between the core and the shell.

  15. Fe3O4@Bi2WO6 Core-Shell Structured Microspheres: Facile Construction and Magnetically Recyclable Photocatalytic Activity Under Visible-Light.

    PubMed

    Zhou, Yu-Xue; Tong, Ling; Zeng, Xiang-Hua; Chen, Xiao-Bing

    2015-12-01

    Core-shell structured Fe3O4@Bi2WO6 composite microspheres (Fe3O4 microspheres as core and Bi2WO6 nanoplates as shell) have been fabricated in a facile and cost effective reflux way. Such fabricated Fe3O4@Bi2WO6 composites show good visible-light driven photocatalytic performance on degradation of rhodamine B (RhB) from solution in presence of H2O2. More importantly, they can be easily harvested from aqueous system for recycle with small loss of their photocatalytic activity upon applying an external magnet. However, this combination of Bi2WO6 photocatalytic activity and Fe3O4 magnetic property endows such composite with a bright perspective in low cost waste water treatment by taking full advantage of solar energy. PMID:26682426

  16. Preparation of Fe 3O 4/poly(styrene-butyl acrylate-[2-(methacryloxy)ethyl]trimethylammonium chloride) by emulsifier-free emulsion polymerization and its interaction with DNA

    NASA Astrophysics Data System (ADS)

    Li, Xiaolong; Liu, Guoqiang; Yan, Wei; Chu, Paul K.; Yeung, Kelvin W. K.; Wu, Shuilin; Yi, Changfeng; Xu, Zushun

    2012-04-01

    Cationic magnetic polymer particles Fe3O4/poly(styrene-butyl acrylate-[2-(methacryloxy)ethyl]trimethylammonium chloride), a type of potential gene carrier, were prepared by emulsifier-free emulsion polymerization with oleic acid modified magnetite Fe3O4, styrene, butyl acrylate and [2-(methacryloxy)ethyl]trimethylammonium chloride) (METAC). The morphology of the particles was characterized by transmission electron microscopy and the composites of particles were characterized by FT-IR spectroscopy, X-ray diffraction. These results showed that magnetic particles were well dispersed in polymers with the content of about 15%(wt/wt). The composites exhibited superparamagnetism and possessed a certain level of magnetic response. The interactions between the particles with calf-thymus DNA (ct DNA) were confirmed by zeta potential measurement, UV-vis spectroscopy and fluorescence spectroscopy. The DNA-binding capacity determined by the agarose gel electrophoresis showed good binding capacity of the emulsion to DNA. These results suggested the potential of the cationic magnetic polymer emulsion as gene target delivery carrier.

  17. Encapsulation of Fe3O4 Nanoparticles into N, S co-Doped Graphene Sheets with Greatly Enhanced Electrochemical Performance.

    PubMed

    Yang, Zunxian; Qian, Kun; Lv, Jun; Yan, Wenhuan; Liu, Jiahui; Ai, Jingwei; Zhang, Yuxiang; Guo, Tailiang; Zhou, Xiongtu; Xu, Sheng; Guo, Zaiping

    2016-01-01

    Particular N, S co-doped graphene/Fe3O4 hybrids have been successfully synthesized by the combination of a simple hydrothermal process and a subsequent carbonization heat treatment. The nanostructures exhibit a unique composite architecture, with uniformly dispersed Fe3O4 nanoparticles and N, S co-doped graphene encapsulant. The particular porous characteristics with many meso/micro holes/pores, the highly conductive N, S co-doped graphene, as well as the encapsulating N, S co-doped graphene with the high-level nitrogen and sulfur doping, lead to excellent electrochemical performance of the electrode. The N-S-G/Fe3O4 composite electrode exhibits a high initial reversible capacity of 1362.2 mAhg(-1), a high reversible specific capacity of 1055.20 mAhg(-1) after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 556.69 mAhg(-1) when cycled at the current density of 1000 mAg(-1), indicating that the N-S-G/Fe3O4 composite is a promising anode candidate for Li-ion batteries. PMID:27296103

  18. Encapsulation of Fe3O4 Nanoparticles into N, S co-Doped Graphene Sheets with Greatly Enhanced Electrochemical Performance

    PubMed Central

    Yang, Zunxian; Qian, Kun; Lv, Jun; Yan, Wenhuan; Liu, Jiahui; Ai, Jingwei; Zhang, Yuxiang; Guo, Tailiang; Zhou, Xiongtu; Xu, Sheng; Guo, Zaiping

    2016-01-01

    Particular N, S co-doped graphene/Fe3O4 hybrids have been successfully synthesized by the combination of a simple hydrothermal process and a subsequent carbonization heat treatment. The nanostructures exhibit a unique composite architecture, with uniformly dispersed Fe3O4 nanoparticles and N, S co-doped graphene encapsulant. The particular porous characteristics with many meso/micro holes/pores, the highly conductive N, S co-doped graphene, as well as the encapsulating N, S co-doped graphene with the high-level nitrogen and sulfur doping, lead to excellent electrochemical performance of the electrode. The N-S-G/Fe3O4 composite electrode exhibits a high initial reversible capacity of 1362.2 mAhg−1, a high reversible specific capacity of 1055.20 mAhg−1 after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 556.69 mAhg−1 when cycled at the current density of 1000 mAg−1, indicating that the N-S-G/Fe3O4 composite is a promising anode candidate for Li-ion batteries. PMID:27296103

  19. Anisotropic magnetoresistance and piezoresistivity in structured Fe3O4-silver particles in PDMS elastomers at room temperature.

    PubMed

    Mietta, José L; Ruiz, Mariano M; Antonel, P Soledad; Perez, Oscar E; Butera, Alejandro; Jorge, Guillermo; Negri, R Martín

    2012-05-01

    Magnetorheological elastomers, MREs, based on elastic organic matrices displaying anisotropic magnetoresistance and piezoresistivity at room temperature were prepared and characterized. These materials are dispersions of superparamagnetic magnetite forming cores of aggregated nanoparticles inside silver microparticles that are dispersed in an elastomeric polymer (poly(dimethylsiloxane), PDMS), curing the polymer in the presence of a uniform magnetic field. In this way, the elastic material becomes structured as the application of the field induces the formation of filaments of silver-covered inorganic material agglomerates (needles) aligned in the direction of the field (parallel to the field). Because the magnetic particles are covered with silver, the MREs are not only magnetic but also electrical conductors. The structuration induces elastic, magnetic, and electrical anisotropic properties. For example, with a low concentration of particles in the elastic matrix (5% w/w) it is possible to obtain resistances of a few ohms when measured parallel to the needles or several megaohms in the perpendicular direction. Magnetite nanoparticles (Fe(3)O(4) NP) were synthesized by the coprecipitation method, and then agglomerations of these NPs were covered with Ag. The average size of the obtained magnetite NPs was about 13 nm, and the magnetite-silver particles, referred to as Fe(3)O(4)@Ag, form micrometric aggregates (1.3 μm). Nanoparticles, microparticles, and the MREs were characterized by XRD, TEM, SEM, EDS, diffuse reflectance, voltammetry, VSM, and SQUID. At room temperature, the synthesized magnetite and Fe(3)O(4)@Ag particles are in a superparamagnetic state (T(B) = 205 and 179 K at 0.01 T as determined by SQUID). The elastic properties and Young's modulus of the MREs were measured as a function of the orientation using a texture analysis device. The magnetic anisotropy in the MRE composite was investigated by FMR. The electrical conductivity of the MRE (

  20. Preparation of multi-functionalized Fe3O4/Au nanoparticles for medical purposes.

    PubMed

    del Mar Ramos-Tejada, María; Viota, Julian L; Rudzka, Katarzyna; Delgado, Angel V

    2015-04-01

    In this work, we investigate a route towards the synthesis of multi-functionalized nanoparticles for medical purposes. The aim is to produce magnetite/gold (Fe3O4/Au) nanoparticles combining several complementary properties, specifically, being able to carry simultaneously an antitumor drug and a selected antibody chosen so as to improve specificity of the drug vehicle. The procedure included, firstly, the preparation of Fe3O4 cores coated with Au nanoparticles: this was achieved by using initially the layer-by-layer technique in order to coat the magnetite particles with a three polyelectrolyte (cationic-anionic-cationic) layer. With this, the particles became a good substrate for the growth of the gold layer in a well-defined core-shell structure. The resulting nanoparticles benefit from the magnetic properties of the magnetite and the robust chemistry and the biostability of gold surfaces. Subsequently, the Fe3O4/Au nanoparticles were functionalized with a humanized monoclonal antibody, bevacizumab, and a chemotherapy drug, doxorubicin. Taken together, bevacizumab enhances the therapeutic effect of chemotherapy agents on some kinds of tumors. In this work we first discuss the morphology of the particles and the electrical characteristics of their surface in the successive synthesis stages. Special attention is paid to the chemical stability of the final coating, and the physical stability of the suspensions of the nanoparticles in aqueous solutions and phosphate buffer. We describe how optical absorbance and electrokinetic data provide a follow up of the progress of the nanostructure formation. Additionally, the same techniques are employed to demonstrate that the composite nanoparticles are capable of loading/releasing doxorubicin and/or bevacizumab. PMID:25710633

  1. Effect of Fe3O4 Nanoparticles on Skin Tumor Cells and Dermal Fibroblasts

    PubMed Central

    Alili, Lirija; Chapiro, Swetlana; Marten, Gernot U.; Schmidt, Annette M.; Zanger, Klaus; Brenneisen, Peter

    2015-01-01

    Iron oxide (Fe3O4) nanoparticles have been used in many biomedical approaches. The toxicity of Fe3O4 nanoparticles on mammalian cells was published recently. Though, little is known about the viability of human cells after treatment with Fe3O4 nanoparticles. Herein, we examined the toxicity, production of reactive oxygen species, and invasive capacity after treatment of human dermal fibroblasts (HDF) and cells of the squamous tumor cell line (SCL-1) with Fe3O4 nanoparticles. These nanoparticles had an average size of 65 nm. Fe3O4 nanoparticles induced oxidative stress via generation of reactive oxygen species (ROS) and subsequent initiation of lipid peroxidation. Furthermore, the question was addressed of whether Fe3O4 nanoparticles affect myofibroblast formation, known to be involved in tumor invasion. Herein, Fe3O4 nanoparticles prevent the expression alpha-smooth muscle actin and therefore decrease the number of myofibroblastic cells. Moreover, our data show in vitro that concentrations of Fe3O4 nanoparticles, which are nontoxic for normal cells, partially reveal a ROS-triggered cytotoxic but also a pro-invasive effect on the fraction of squamous cancer cells surviving the treatment with Fe3O4 nanoparticles. The data herein show that the Fe3O4 nanoparticles appear not to be adequate for use in therapeutic approaches against cancer cells, in contrast to recently published data with cerium oxide nanoparticles. PMID:26090418

  2. Supercritical carbon dioxide assisted deposition of Fe(3)O(4) nanoparticles on hierarchical porous carbon and their lithium-storage performance.

    PubMed

    Wang, Lingyan; Zhuo, Linhai; Zhang, Chao; Zhao, Fengyu

    2014-04-01

    A composite of highly dispersed Fe3 O4 nanoparticles (NPs) anchored in three-dimensional hierarchical porous carbon networks (Fe3 O4 /3DHPC) as an anode material for lithium-ion batteries (LIBs) was prepared by means of a deposition technique assisted by a supercritical carbon dioxide (scCO2 )-expanded ethanol solution. The as-synthesized Fe3 O4 /3DHPC composite exhibits a bimodal porous 3D architecture with mutually connected 3.7 nm mesopores defined in the macroporous wall on which a layer of small and uniform Fe3 O4 NPs was closely coated. As an anode material for LIBs, the Fe3 O4 /3DHPC composite with 79 wt % Fe3 O4 (Fe3 O4 /3DHPC-79) delivered a high reversible capacity of 1462 mA h g(-1) after 100 cycles at a current density of 100 mA g(-1) , and maintained good high-rate performance (728, 507, and 239 mA h g(-1) at 1, 2, and 5 C, respectively). Moreover, it showed excellent long-term cycling performance at high current densities, 1 and 2 A g(-1) . The enhanced lithium-storage behavior can be attributed to the synergistic effect of the porous support and the homogeneous Fe3 O4 NPs. More importantly, this straightforward, highly efficient, and green synthetic route will definitely enrich the methodologies for the fabrication of carbon-based transition-metal oxide composites, and provide great potential materials for additional applications in supercapacitors, sensors, and catalyses. PMID:24590487

  3. Spin-resolved photoelectron spectroscopy of Fe3O4

    SciTech Connect

    Morton, Simon; Waddill, Dan; Kim, S H.; Schuller, I K.; Chambers, Scott A.; Tobin, James G.

    2002-08-01

    The existence of a new class of magnetic materials displaying metallic character for one electron spin population and insulating character for the other was first populated by DeGroot et al. in 1983 based on theoretical band structure calculations of the ferromagnetic Heusler alloy NiMnSb. Since then such half metallic materials, which by definition possess 100% electron polarization at the Fermi energy, have attracted considerable theoretical, experimental, and technological interest as potential pure spin sources for use in spintronic devices. In addition to Heusler alloys (e.g. NiMnSb, PtMnSb), half metallic character has also been predicted to occur in a wide range of manganites (e.g. La1-xCaxMnO3, La1-x-SrxMnO3), metallic oxides (e.g. Fe3O4, CrO2) and CMR systems. However, such predictions have proven to be extremely difficult to confirm experimentally. Possible reasons for this include the theoretical limitations arising from the complex crystallographic structure of many such materials and limitations in applying the single electron picture to materials where strong electron correlation may be present; this is compounded by experimental difficulties posed by their structural complexity and issues such as surface contamination, segregation, and reconstruction.

  4. Optimization of Fe3 O4 Nanoparticle Synthesis

    NASA Astrophysics Data System (ADS)

    Vila, E.; Stojak Repa, K.; Srikanth, H.; Phan, Mh

    Magnetic nanoparticles have been of great interest for the past several decades due to the increasing demands of technology as a direct result of device miniaturization. Additionally, they are interesting for biomedical applications, such as magnetic hyperthermia, because of their controllable size and shape, which can make them compatible with biological entities such as cells or viruses. In this study, iron oxide nanoparticles were synthesized through a thermal decomposition process. The original recipe was altered by changing the type and amounts of reagents used; the reaction time was also changed. Specifically, the amount of surfactants and solvent were altered, and the typical co-surfactant, 1,2-hexadecanediol was substituted by 1,2-tetradecanediol. Finally, a systematic reflux time study was conducted to determine the importance of reaction time to the synthetic process. Each sample was analyzed structurally via XRD to confirm the Fe3O4 phase and TEM to confirm their size. Several samples were also measured in a standard magnetometer to observe changes in their magnetic properties. Results from the systematic study will be presented here.

  5. Discovery of hard-magnetic domains in two-dimensional arrays of soft-magnetic Fe3O4 nanocubes

    NASA Astrophysics Data System (ADS)

    Ma, Ji; Sun, Shuangshuang; Wang, Tiantian; Chen, Kezheng

    2015-08-01

    In this study, abnormal hard-magnetic domains were discovered in Fe3O4@C composite material, in which well-ordered 16-nm-sized Fe3O4 cubes were tightly embedded into carbon sheets of tens of nanometers thick. It was found that ca. 40 columns of Fe3O4 nanocubes magnetically self-assembled into a single strip-type domain with perpendicular magnetic anisotropy. More strikingly, remarkable domain misalignments, which were very similar to common edge dislocations among atomic planes in crystal lattices, were clearly observed and termed as "domain dislocation" in this work. The hard-magnetic properties of Fe3O4@C material, including large coercivity of 2150 Oe, high MR/MS value of 0.9, and strong anisotropy energy of 3.772 × 105 erg/cm3, were further ascertained by carefully designed electromagnetic absorption contrast experiments. It is anticipated that the discovery of hard-magnetic domains and domain dislocations within 2-D arrays of soft-magnetic nanomaterials will shed new light on the development of high-density perpendicular magnetic recording industry.

  6. Electrocatalytic oxidation behavior of NADH at Pt/Fe3O4/reduced-graphene oxide nanohybrids modified glassy carbon electrode and its determination.

    PubMed

    Roushani, Mahmoud; Hoseini, S Jafar; Azadpour, Mitra; Heidari, Vahid; Bahrami, Mehrangiz; Maddahfar, Mahnaz

    2016-10-01

    We have developed Pt/Fe3O4/reduced-graphene oxide nanohybrids modified glassy carbon (Pt/Fe3O4/RGO/GC) electrode as a novel system for the preparation of electrochemical sensing platform. Characterization of as-made composite was determined using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM) and energy-dispersive analysis of X-ray (EDAX) where the Pt, Fe, Si, O and C elements were observed. The Pt/Fe3O4/RGO/GC electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Due to the synergistic effect between Pt, Fe3O4 and RGO, the nanohybrid exhibited excellent performance toward dihydronicotinamide adenine dinucleotide (NADH) oxidation in 0.1M phosphate buffer solution, pH7.0, with a low detection limit of 5nM. PMID:27287119

  7. Facile synthesis and excellent recyclable photocatalytic activity of pine cone-like Fe3O4@Cu2O/Cu porous nanocomposites.

    PubMed

    Wang, Haisheng; Hu, Yongan; Jiang, Yang; Qiu, Lingguang; Wu, Haibin; Guo, Ben; Shen, Yuhua; Wang, Yang; Zhu, Ling; Xie, Anjian

    2013-04-14

    L-Cys-modified Fe3O4 was first prepared by a one-step partially-reduced method under mild conditions. Then, novel pine cone-like Fe3O4@Cu2O/Cu nanocomposites (NCs) with photomagnetic difunction were successfully synthesized via a one-pot solvothermal method on Fe3O4 without any additional linker or reducer. The average diameter of the as-synthesized products was about 4 μm, and the products were orderly assembled into many sheets with an average thickness of ~100 nm, possessing a porous structure. A possible formation mechanism of Fe3O4@Cu2O/Cu NCs involving interfacial recognization of ions, nucleation, aggregation, in situ transformation from Cu2O to Cu and Ostwald ripening process is proposed. The pine cone-like porous composites show excellent photocatalytic activity such that MO degradation efficiency is about 96% at an irradiation time of 20 min under visible light. Also, the composites present higher stability than Fe3O4@Cu2O and do not exhibit any significant loss after five recycles for the photodegradation of MO. The above results demonstrate that Cu could improve the photocatalytic activity of NCs and also inhibit the photocorrosion behavior of NCs. These novel Fe3O4@Cu2O/Cu composite materials are ideal candidates in water treatment and environmental cleaning as well as in magnetic applications, etc. PMID:23380894

  8. One-Pot Synthesis of Pomegranate-Structured Fe3 O4 /Carbon Nanospheres-Doped Graphene Aerogel for High-Rate Lithium Ion Batteries.

    PubMed

    He, Dafang; Li, Lixian; Bai, Fengjuan; Zha, Chenyang; Shen, Liming; Kung, Harold H; Bao, Ningzhong

    2016-03-18

    A unique hierarchically nanostructured composite of iron oxide/carbon (Fe3O4/C) nanospheres-doped three-dimensional (3D) graphene aerogel has been fabricated by a one-pot hydrothermal strategy. In this novel nanostructured composite aerogel, uniform Fe3O4 nanocrystals (5-10 nm) are individually embedded in carbon nanospheres (ca. 50 nm) forming a pomegranate-like structure. The carbon matrix suppresses the aggregation of Fe3O4 nanocrystals, avoids direct exposure of the encapsulated Fe3O4 to the electrolyte, and buffers the volume expansion. Meanwhile, the interconnected 3D graphene aerogel further serves to reinforce the structure of the Fe3O4/C nanospheres and enhances the electrical conductivity of the overall electrode. Therefore, the carbon matrix and the interconnected graphene network entrap the Fe3O4 nanocrystals such that their electrochemical function is retained even after fracture. This novel hierarchical aerogel structure delivers a long-term stability of 634 mA h g(-1) over 1000 cycles at a high current density of 6 A g(-1) (7 C), and an excellent rate capability of 413 mA h g(-1) at 10 A g(-1) (11 C), thus exhibiting great potential as an anode composite structure for durable high-rate lithium-ion batteries. PMID:26879124

  9. Sol-gel derived silica/chitosan/Fe3O4 nanocomposite for direct electrochemistry and hydrogen peroxide biosensing

    NASA Astrophysics Data System (ADS)

    Satvekar, R. K.; Rohiwal, S. S.; Tiwari, A. P.; Raut, A. V.; Tiwale, B. M.; Pawar, S. H.

    2015-01-01

    A novel strategy to fabricate hydrogen peroxide third generation biosensor has been developed from sol-gel of silica/chitosan (SC) organic-inorganic hybrid material assimilated with iron oxide magnetic nanoparticles (Fe3O4). The large surface area of Fe3O4 and porous morphology of the SC composite facilitates a high loading of horseradish peroxidase (HRP). Moreover, the entrapped enzyme preserves its conformation and biofunctionality. The fabrication of hydrogen peroxide biosensor has been carried out by drop casting of the SC/F/HRP nanocomposite on glassy carbon electrode (GCE) for study of direct electrochemistry. The x-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) confirms the phase purity and particle size of as-synthesized Fe3O4 nanoparticles, respectively. The nanocomposite was characterized by UV-vis spectroscopy, fluorescence spectroscopy and Fourier transform infrared (FTIR) for the characteristic structure and conformation of enzyme. The surface topographies of the nanocomposite thin films were investigated by scanning electron microscopy (SEM). Dynamic light scattering (DLS) was used to determine the particle size distribution. The electrostatic interactions of the SC composite with Fe3O4 nanoparticles were studied by the zeta potential measurement. Electrochemical impedance spectroscopy (EIS) of the SC/F/HRP/GCE electrode displays Fe3O4 nanoparticles as an excellent candidate for electron transfer. The SC/F/HRP/GCE exhibited a pair of well-defined quasi reversible cyclic voltammetry peaks due to the redox couple of HRP-heme Fe (III)/Fe (II) in pH 7.0 potassium phosphate buffer. The biosensor was employed to detect H2O2 with linear range of 5 μM to 40 μM and detection limit of 5 μM. The sensor displays excellent selectivity, sensitivity, good reproducibility and long term stability.

  10. Superparamagnetic Fe3O4 particles formed by oxidation of pyrite heated in an anoxic atmosphere

    USGS Publications Warehouse

    Thorpe, A.N.; Senftle, F.E.; Talley, R.; Hetherington, S.; Dulong, F.

    1990-01-01

    As a follow-up to previous gas analysis experiments in which pyrite was heated to 681 K in an anoxic (oxygen starved) atmosphere, the first oxidation product, FeSO4, was studied as a bulk material. No decomposition of FeSO4 to Fe3O4 was observed in the temperature range studied. The lack of decomposition of bulk FeSO4 to Fe3O4 suggests that FeS2 oxidizes directly to Fe3O4, or that FeSO4, FeS2 and O2 react together to form Fe3O4. Magnetic susceptibility and magnetization measurements, along with magnetic hysteresis curves, show that small particles of Fe3O4 form on the pyrite surface, rather than a continuous layer of bulk Fe3O4. A working model describing the oxidation steps is presented. ?? 1990.

  11. Ultrasonic synthesis of polyaniline nanotubes containing Fe 3O 4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Lu, Xiaofeng; Mao, Hui; Chao, Danming; Zhang, Wanjin; Wei, Yen

    2006-08-01

    Polyaniline (PANI) nanotubes containing Fe 3O 4 nanoparticles were synthesized under ultrasonic irradiation of the aqueous solutions of aniline, ammonium peroxydisulfate (APS), phosphoric acid (H 3PO 4), and the quantitative amount of Fe 3O 4. It was found that the obtained samples had the morphologies of nanotubes. TEM images and selected area electronic diffractions showed that Fe 3O 4 nanoparticles were embedded in PANI nanotubes. We thought that the mechanism of the formation of PANI/Fe 3O 4 nanotubes could be attributed to the ultrasonic irradiation and the H 3PO 4-aniline salt template. The molecular structure of PANI/Fe 3O 4 nanotubes were characterized by Fourier transform infrared spectroscopy (FTIR), UV-vis absorption spectra and X-ray diffraction (XRD). The conductivity and magnetic properties of the PANI nanotubes containing Fe 3O 4 nanoparticles were also investigated.

  12. Electrochemical sensing property of Mn doped Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Suresh, R.; Giribabu, K.; Manigandan, R.; Vijayalakshmi, L.; Stephen, A.; Narayanan, V.

    2013-02-01

    The Mn doped Fe3O4 nanoparticles were synthesized by hydrothermal method. The prepared nanoparticles were characterized by X-ray diffraction (XRD) analysis, UV-Visible spectroscopy (UV-Vis) and field emission scanning electron microscopy (FE-SEM). The electrochemical sensing property of pure and Mn doped Fe3O4 nanoparticles were examined using uric acid (UA) as an analyte. The obtained results indicated that the Mn doped Fe3O4 nanoparticles exhibited higher electrocatalytic activity towards UA.

  13. Facile synthesis of superparamagnetic Fe3O4@Au nanoparticles for photothermal destruction of cancer cells.

    PubMed

    Ren, Jinfeng; Shen, Shun; Pang, Zhiqing; Lu, Xiaohui; Deng, Chunhui; Jiang, Xinguo

    2011-11-14

    Superparamagnetic Fe(3)O(4) nanoparticles with positive surface ξ-potential were synthesized via a solvothermal route. After Fe(3)O(4) was mixed with HAuCl(4) and NaBH(4), the reduced Au nanoparticles could be directly adsorbed onto the surface of Fe(3)O(4) nanoparticles. The as-synthesized nanocomposites were successfully applied to photothermal destruction of cancer cells. PMID:21952492

  14. Synthesis, characterization and magnetorheological study of 3-aminopropyltriethoxysilane-modified Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Wang, Guangshuo; Ma, Yingying; Tong, Yu; Dong, Xufeng

    2016-03-01

    In this study, monodisperse Fe3O4 nanoparticles were synthesized successfully using a sonochemical method in the presence of 3-aminopropyltriethoxysilane (APTES). The morphology, microstructure and magnetic properties of the bare Fe3O4 and APTES-coated Fe3O4 were investigated in detail by TEM, XRD, FTIR and SQUID. It was found that APTES-coated Fe3O4 showed relatively good dispersion with a narrow size distribution of 8.4 ± 2.1 nm diameter. The functionalization of Fe3O4 was proved to be covalent linking between Fe3O4 and APTES. The field-dependent magnetization curve indicated superparamagnetic behavior of Fe3O4-APTES with a saturation magnetization (M s) of 70.5 emu g-1 at room temperature. A magnetorheological (MR) fluid was prepared using the obtained Fe3O4-APTES nanoparticles with 25 wt% particles, and its MR properties were tested using a Physica MCR301 rheometer fitted with an MRmodule. The results showed that the as-prepared APTES-coated Fe3O4 nanoparticle-based MR fluid exhibited typical MR effects, with increasing viscosity, shear stress and yield stress depending on the applied magnetic field strength.

  15. Efficient synthesis of core@shell Fe3O4@Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Alonso-Cristobal, Paulino; Laurenti, Marco; Lopez-Cabarcos, Enrique; Rubio-Retama, Jorge

    2015-07-01

    The synthesis of Fe3O4@Au nanoparticles has received much attention due to promising applications in the biomedical field. In this work, we produced Fe3O4@Au nanoparticles by using a two-step solvothermal route that employed Fe3O4 nanoparticles as seeds for the Au deposition. Although this protocol leads to highly monodisperse and reproducible Fe3O4@Au nanoparticles it was necessary to perform a systematic study to have a better understanding, improve the yield and allow us to obtain a tunable result. We demonstrated that the Au:Fe3O4 ratio is a key parameter that, contrary to what could be expected, does not influence the Au shell thickness. However, this parameter should be optimized because it strongly influences the yield. When the Au:Fe3O4 ratio was low there were plenty of uncoated Fe3O4 nanoparticles, whereas when the Au:Fe3O4 ratio was high there could be some pure Au nanoparticles together with the desired Fe3O4@Au nanoparticles. Furthermore we demonstrated that the Au shell thickness can be tuned by varying the reaction temperature. This paper describes the influence of both parameters and proposes a mechanism of the synthetic process by studying parametrically the morphological and structural evolution of the nanoparticles by TEM, DLS, SQUID and UV-vis spectroscopy.

  16. Core-shell-corona doxorubicin-loaded superparamagnetic Fe3O4 nanoparticles for cancer theranostics.

    PubMed

    Semkina, A; Abakumov, M; Grinenko, N; Abakumov, A; Skorikov, A; Mironova, E; Davydova, G; Majouga, A G; Nukolova, N; Kabanov, A; Chekhonin, V

    2015-12-01

    Superparamagnetic iron oxide magnetic nanoparticles (MNPs) are successfully used as contrast agents in magnetic-resonance imaging. They can be easily functionalized for drug delivery functions, demonstrating great potential for both imaging and therapeutic applications. Here we developed new pH-responsive theranostic core-shell-corona nanoparticles consisting of superparamagentic Fe3O4 core that displays high T2 relaxivity, bovine serum albumin (BSA) shell that binds anticancer drug, doxorubicin (Dox) and poly(ethylene glycol) (PEG) corona that increases stability and biocompatibility. The nanoparticles were produced by adsorption of the BSA shell onto the Fe3O4 core followed by crosslinking of the protein layer and subsequent grafting of the PEG corona using monoamino-terminated PEG via carbodiimide chemistry. The hydrodynamic diameter, zeta-potential, composition and T2 relaxivity of the resulting nanoparticles were characterized using transmission electron microscopy, dynamic light scattering, thermogravimetric analysis and T2-relaxometry. Nanoparticles were shown to absorb Dox molecules, possibly through a combination of electrostatic and hydrophobic interactions. The loading capacity (LC) of the nanoparticles was 8 wt.%. The Dox loaded nanoparticles release the drug at a higher rate at pH 5.5 compared to pH 7.4 and display similar cytotoxicity against C6 and HEK293 cells as the free Dox. PMID:26595387

  17. Thermodynamic Properties of α-Fe2O3 and Fe3O4 Nanoparticles

    DOE PAGESBeta

    Spencer, Elinor C.; Ross, Nancy L.; Olsen, Rebecca E.; Huang, Baiyu; Kolesnikov, Alexander I.; Woodfield, Brian F.

    2015-04-21

    Here we comprehansively assessed the thermodynamic properties of hydrated α-Fe2O3 (hematite) and Fe3O4 (magnetite) nanoparticles. In addition to 9 nm Fe3O4, three α-e2O3nanoparticles samples of different sizes (11, 14, and 25 nm) and bulk α-e2O3 have been evaluated by inelastic neutron scattering methods. The contribution of the two-level magnetic spin flip transition to the heat capacity of the α-e2O3 particles has been determined. The isochoric heat capacity of the water confined on the surface of these two types of iron oxide particles have been calculated from their INS spectra, and is affected by the chemical composition of the underlying particle.more » Furthermore, the heat capacity and dynamics of the particle hydration layers appear to be influenced by a complex array of factors including particle size, water coverage, and possibly the magnetic state of the particle itself.« less

  18. Magnetic properties in oriented platelet Fe3O4 particles prepared by the polyol method using α-FeOOH as precursors

    NASA Astrophysics Data System (ADS)

    Kishimoto, Mikio; Isaka, Daiki; Horiuchi, Akari; Yanagihara, Hideto; Kita, Eiji

    2014-02-01

    Magnetic properties of platelet Fe3O4 particles were studied to apply them to magnetic hyperthermia or thermoablation using hysteresis-loss heating. As precursor materials, platelet α-FeOOH particles were synthesized by a hydrothermal treatment of the precipitated Fe3+ ions in an alkaline solution of ethanolamine. Spinel-structured iron oxide particles were obtained from the platelet α-FeOOH particles by a liquid-phase reduction process using tetra-ethylene glycol as the reducing agent and were recognized as platelet particles with size 30-100 nm by transmission electron microscopy. Their chemical composition and crystal structure were confirmed to be that of Fe3O4 by X-ray diffraction and Mössbauer analyses. The coercive force and saturation magnetization of the Fe3O4 particles were 11.9 kA/m and 77.9 Am2/kg, respectively. A tape was prepared by orientating the platelet Fe3O4 particles in such a way that the particle planes were parallel to the tape plane. The calculated magnetic anisotropy field of the Fe3O4 particles was about two times larger than the in-plane coercive force of 12.6 kA/m of the oriented tape. The saturation field in direction perpendicular to the oriented tape was 390 kA/m, which is close to the demagnetizing field in the platelet Fe3O4 particles.

  19. Synthesis, characterisation of polyaniline-Fe3O4 magnetic nanocomposite and its application for removal of an acid violet 19 dye

    NASA Astrophysics Data System (ADS)

    Patil, Manohar R.; Khairnar, Subhash D.; Shrivastava, V. S.

    2016-04-01

    The present work deals with the development of a new method for the removal of dyes from an aqueous solution using polyaniline (PANI)-Fe3O4 magnetic nanocomposite. It is synthesised in situ through self-polymerisation of monomer aniline. Photocatalytic degradation studies were carried out for cationic acid violet 19 (acid fuchsine) dye using PANI-Fe3O4 nanocomposite in aqueous solution. Different parameters like catalyst dose, contact time and pH have been studied to optimise reaction condition. The optimum conditions for the removal of the dye are initial concentration 20 mg/l, adsorbent dose 6 gm/l, pH 7. The EDS technique gives elemental composition of synthesised PANI-Fe3O4. The SEM and XRD studies were carried for morphological feature characteristics of PANI-Fe3O4 nanocomposite. The VSM (vibrating sample magnetometer) gives magnetic property of PANI-Fe3O4 nanocomposite; also FT-IR analysis gives characteristics frequency of synthesised PANI-Fe3O4. Besides the above studies kinetic study has also been carried out.

  20. 99mTc radiolabelling of Fe3O4-Au core-shell and Au-Fe3O4 dumbbell-like nanoparticles

    NASA Astrophysics Data System (ADS)

    Felber, M.; Alberto, R.

    2015-04-01

    The development of nanoparticle-based dual-modality probes for magnetic resonance imaging (MRI) and positron emission tomography (PET) or single photon emission computed tomography (SPECT) is increasingly growing in importance. One of the most commonly used radionuclides for clinical SPECT imaging is 99mTc and the labelling of Fe3O4 nanoparticles with 99mTc was shown to be a successful strategy to obtain dual-modality imaging agents. In this work, we focus on gold containing magnetic nanomaterials. The radiolabelling of magnetic Fe3O4-Au core-shell and Fe3O4-Au dumbbell-like nanoparticles with the [99mTc(CO)3]+ fragment is described. The key elements for this 99mTc labelling approach are novel coating ligands, consisting of an anchor for the Au surface, a polyethylene glycol linker and a strong chelator for the [99mTc(CO)3]+ moiety.The development of nanoparticle-based dual-modality probes for magnetic resonance imaging (MRI) and positron emission tomography (PET) or single photon emission computed tomography (SPECT) is increasingly growing in importance. One of the most commonly used radionuclides for clinical SPECT imaging is 99mTc and the labelling of Fe3O4 nanoparticles with 99mTc was shown to be a successful strategy to obtain dual-modality imaging agents. In this work, we focus on gold containing magnetic nanomaterials. The radiolabelling of magnetic Fe3O4-Au core-shell and Fe3O4-Au dumbbell-like nanoparticles with the [99mTc(CO)3]+ fragment is described. The key elements for this 99mTc labelling approach are novel coating ligands, consisting of an anchor for the Au surface, a polyethylene glycol linker and a strong chelator for the [99mTc(CO)3]+ moiety. Electronic supplementary information (ESI) available: Analyses of Fe3O4-Au core-shell nanoparticles; analyses of Au-Fe3O4 dumbbell-like nanoparticles; 99mTc labelling of Fe3O4-Au core-shell nanoparticles; 99mTc complexes; 99mTc labelling of Au-Fe3O4 dumbbell-like nanoparticles; syntheses coating ligands. See

  1. Preparation and characterization of magnetic Fe3O4-chitosan nanoparticles loaded with isoniazid

    NASA Astrophysics Data System (ADS)

    Qin, H.; Wang, C. M.; Dong, Q. Q.; Zhang, L.; Zhang, X.; Ma, Z. Y.; Han, Q. R.

    2015-05-01

    A novel and simple method has been proposed to prepare magnetic Fe3O4-chitosan nanoparticles loaded with isoniazid (Fe3O4/CS/INH nanocomposites). Efforts have been made to develop isoniazid (INH) loaded chitosan (CS) nanoparticles by ionic gelation of chitosan with tripolyphosphate (TPP). The factors that influence the preparation of chitosan nanoparticles, including the TPP concentration, the chitosan/TPP weight ratio and the chitosan concentration on loading capacity and encapsulation efficiency of chitosan nanoparticles were studied. The magnetic Fe3O4 nanoparticles were prepared by co-precipitation method of Fe2+ and Fe3+. Then the magnetic Fe3O4/CS/INH nanocomposites were prepared by ionic gelation method. The magnetic Fe3O4 nanoparticles and magnetic Fe3O4/CS/INH nanocomposites were characterized by XRD, TEM, FTIR and SQUID magnetometry. The in vitro release of Fe3O4/CS/INH nanocomposites showed an initial burst release in the first 10 h, followed by a more gradual and sustained release for 48 h. It is suggested that the magnetic Fe3O4/CS/INH nanocomposites may be exploited as potential drug carriers for controlled-release applications in magnetic targeted drugs delivery system.

  2. An effective way to increase the high-frequency permeability of Fe3O4 nanorods.

    PubMed

    Ren, Xiao; Yang, Haitao; Tang, Jin; Li, Zi-An; Su, Yi Kun; Geng, Sai; Zhou, Jun; Zhang, Xiangqun; Cheng, Zhaohua

    2016-07-14

    Uniform Fe3O4 magnetic nanorods (NRs) were successfully synthesized and oriented in epoxy resin under a rotating magnetic field. Magnetic induction fields within and around a single Fe3O4 nanorod in the remanence state were obtained by off-axis electron holography. The induction fields indicated a single domain state of the highly anisotropic Fe3O4 nanorod due to its strong magnetic shape anisotropy. Quantitative magnetic moment analysis of the obtained phase image yielded an average magnetization of 0.53 T of a single Fe3O4 nanorod. Moreover, the real part of the permeability (μ') of magnetic-oriented Fe3O4 NRs is obviously higher than that of random Fe3O4 NRs in the GHz range. The oriented Fe3O4 NRs exhibit a higher resonance peak at 4.75 GHz compared to the bulk counterpart (1.2 GHz) in the frequency dependence of μ in the range of 1-10 GHz. Moreover, the calculated μ value of the oriented Fe3O4 NRs could be improved to 4.22 with the increased dipolar interaction strength using the OOMMF software. These results could play a guiding significance in the development of an effective method to improve the permeability of magnetic nanomaterials at GHz working frequency. PMID:27305587

  3. Sea-urchin-like Fe3O4@C@Ag particles: an efficient SERS substrate for detection of organic pollutants

    NASA Astrophysics Data System (ADS)

    Ye, Yingjie; Chen, Jin; Ding, Qianqian; Lin, Dongyue; Dong, Ronglu; Yang, Liangbao; Liu, Jinhuai

    2013-06-01

    Ag-coated sea-urchin-like Fe3O4@C core-shell particles can be synthesized by a facile one-step solvothermal method, followed by deposition of high-density Ag nanoparticles onto the carbon surface through an in situ growth process, respectively. The as-synthesized Ag-coated Fe3O4@C particles can be used as a surface-enhanced Raman scattering (SERS) substrate holding reproducible properties under an external magnetic force. The magnetic function of the particles allows concentrating the composite particles into small spatial regions, which can be exploited to decrease the amount of material per analysis while improving its SERS detection limit. In contrast to the traditional SERS substrates, the present Fe3O4@C@Ag particles hold the advantages of enrichment of organic pollutants for improving SERS detection limit and recycled utilization.Ag-coated sea-urchin-like Fe3O4@C core-shell particles can be synthesized by a facile one-step solvothermal method, followed by deposition of high-density Ag nanoparticles onto the carbon surface through an in situ growth process, respectively. The as-synthesized Ag-coated Fe3O4@C particles can be used as a surface-enhanced Raman scattering (SERS) substrate holding reproducible properties under an external magnetic force. The magnetic function of the particles allows concentrating the composite particles into small spatial regions, which can be exploited to decrease the amount of material per analysis while improving its SERS detection limit. In contrast to the traditional SERS substrates, the present Fe3O4@C@Ag particles hold the advantages of enrichment of organic pollutants for improving SERS detection limit and recycled utilization. Electronic supplementary information (ESI) available: Additional XRD patterns and SEM images of Fe3O4@C particles, SERS spectra of 4-ATP and 4-MPY using Fe3O4@C@Ag particles as the active substrates, magnetic behaviour of Fe3O4@C and Fe3O4@C@Ag particles. See DOI: 10.1039/c3nr01273e

  4. Spectroscopic characterization of magnetic Fe3O4@Au core shell nanoparticles.

    PubMed

    Fouad, Dina M; El-Said, Waleed A; Mohamed, Mona B

    2015-04-01

    The magnetic nanoparticles iron oxide (Fe3O4) nanoparticles and iron oxide/gold core-shell (Fe3O4/Au) nanoparticles were synthesized and their catalytic photo-degradation activity towards malathion as example of organophosphorus pesticides were reported. Iron oxide (Fe3O4) magnetic nanoparticle was successfully prepared through co-precipitation method by the reduction of ferric chloride (FeCl3) using ascorbic acid. The morphology of the prepared nanoparticles was characterized by the TEM and XRD (X-ray diffraction) techniques. Degradation of 10 ppm of malathion in the presence of these nanoparticles under UV radiation was monitored using (HPLC) and UV-visible spectra. Fe3O4/Au nanoparticles showed higher efficiency in photo-degradation of malathion than Fe3O4 ones. PMID:25617979

  5. Inversion of spin dependent photocurrent at Fe3O4/modulation doped GaAs heterointerfaces

    NASA Astrophysics Data System (ADS)

    Shirahata, Y.; Wada, E.; Itoh, M.; Taniyama, T.

    2011-04-01

    We demonstrate inversion of the spin dependent photocurrent across an Fe3O4/modulation doped GaAs interface under optical spin orientation condition. The spin dependent photocurrent for fully epitaxial Fe3O4/GaAs and Fe/GaAs interfaces clearly show the opposite magnetic field dependence, where the spin filtering efficiency for the Fe3O4/GaAs decreases with increasing magnetic field. The results clearly indicate that the spin polarization of the Fe3O4 layer has the opposite sign to that of Fe at the Fermi energy, consistent with theoretical predictions, and the result is a consequence of the atomically flat Fe3O4/GaAs interface we obtained.

  6. Magnetic Properties of CoFe_2O4 and Fe_3O_4

    NASA Astrophysics Data System (ADS)

    Rodriguez, Robert; Chan, T.; Kenning, G. G.; Huang, L.; Yan, Y.

    2002-03-01

    In order to optimize the magnetization of magnetic nanoparticles for use as Magnetic Resonance Imaging contrast agents and other in vivo biological applications, we have synthesized CoFe_2O_4(Liu, C.; Bingsuo, Z.; Rondinone, A.J.; Zhang, Z.J. J. Am. Chem. Soc.) 122, 6263 (2000). and Fe_3O_4(Shen, T.; Weissleder, R.; Papisov, M.; Bogdanov, A.; Brady, T. MRM) 29, 599 (1993). magnetic nanoparticles of sizes 5, 8, and 11nm using water-in-oil reverse micelles. Size was determined using Dynamic Light Scattering (DLS), X-Ray Diffraction (XRD), and High Pressure Liquid Chromatography (HPLC). Magnetic properties were measure from 10K-340K using SQUID magnetometry. Magnetization as a function of magnetic field has been performed at approximately body temperature ( ~310K) in order to help us determine the optimal size and composition for in vivo application.

  7. Fe3O4/PS magnetic nanoparticles: Synthesis, characterization and their application as sorbents of oil from waste water

    NASA Astrophysics Data System (ADS)

    Yu, Liuhua; Hao, Gazi; Gu, Junjun; Zhou, Shuai; Zhang, Ning; Jiang, Wei

    2015-11-01

    In this work, Fe3O4/PS composites with a rough surface and different coating rates were successfully designed and synthesized by emulsion polymerization. We carried out some comparative experiments to compare magnetic properties and oil absorption properties of the nano-magnetic materials. It had been found that several prepared groups of magnetic nanocomposites have a core-shell structure and good coating rates. These nanoparticles combined with unsinked, highly hydrophobic and superoleophilic properties. The absorption capacity of Fe3O4/PS composites for organic solvents and the composites could absorb diesel oil up to 2.492 times of its own weight. It is more important that the oil could be readily removed from the surfaces of nanoparticles by a simple ultrasonic treatment whereas the nanocomposites particles still kept highly hydrophobic and superoleophilic characteristics. With a combination of simple synthesis process, low density, magnetic responsibility and excellent hydrophobicity, Fe3O4/PS nanocomposites as a promising absorbent have great potential in the application of spilled oil recovery and environmental protection.

  8. Combined use of lightweight magnetic Fe3O4-coated hollow glass spheres and electrically conductive reduced graphene oxide in an epoxy matrix for microwave absorption

    NASA Astrophysics Data System (ADS)

    Wang, Junpeng; Wang, Jun; Zhang, Bin; Sun, Yu; Chen, Wei; Wang, Tao

    2016-03-01

    Epoxy resin based lightweight composites comprising Fe3O4-coated hollow glass spheres (HGS@Fe3O4) and reduced graphene oxide (RGO) were prepared. Impedance matching condition and electromagnetic wave attenuation characteristic are used for analysis of the reflection loss (RL) performance of the composites. Compared with pure HGS@Fe3O4 and RGO composite, the -10 dB absorption bandwidth and the minimum RL of the hybrid composites are enhanced. RL values less than -10 dB are obtained in a wide frequency range and the corresponding bandwidth can reach up to 3.6 GHz when an appropriate absorber thickness is chosen. The density of the hybrid composite is in the range of 0.57-0.72 g/cm3, which is attractive candidate for a new type of lightweight microwave absorber.

  9. Facile synthesis of multifunctional attapulgite/Fe3O4/polyaniline nanocomposites for magnetic dispersive solid phase extraction of benzoylurea insecticides in environmental water samples.

    PubMed

    Yang, Xiaoling; Qiao, Kexin; Ye, Yiren; Yang, Miyi; Li, Jing; Gao, Haixiang; Zhang, Sanbing; Zhou, Wenfeng; Lu, Runhua

    2016-08-31

    In this study, the superparamagnetic attapulgite/Fe3O4/polyaniline (ATP/Fe3O4/PANI) nanocomposites were successfully synthesized by a one-pot method. Fe (III) was applied as both the oxidant for the oxidative polymerization of aniline and the single iron source of Fe3O4 formed by the redox reaction between aniline and Fe (III). The ATP/Fe3O4/PANI was used as sorbent for magnetic dispersive solid phase extraction (MDSPE) of benzoylurea insecticides (BUs) in environmental water samples. The as-prepared nanocomposite sorbents were characterized by Fourier transform infrared spectra (FT-IR), X Ray diffraction (XRD), scanning electron microscopy(SEM), transmission electron microscopy (TEM), and vibrating sample magnetometry. Various experimental parameters affecting the ATP/Fe3O4/PANI-based MDSPE procedure, including the composition of the nanocomposite sorbents, amount of ATP/Fe3O4/PANI nanocomposites, vortex time, pH, and desorption conditions were investigated. Under the optimal conditions, a good linearity was observed for all target analytes, with correlation coefficients (r(2)) ranging from 0.9985 to 0.9997; the limits of detection (LOD) were in the range of 0.02-0.43 μg L(-1), and the recoveries of analytes using the proposed method ranged between 77.37% and 103.69%. The sorbents exhibited an excellent reproducibility in the range of 1.52-5.27% in extracting the five target analytes. In addition, the intra-day and inter-day precision values were found to be in the range of 0.78-6.86% and 1.66-8.41%, respectively. Finally, the proposed ATP/Fe3O4/PANI-based MDSPE method was successfully applied to analyze river water samples by rapid preconcentration of BUs. PMID:27506351

  10. Fates of Fe3O4 and Fe3O4@SiO2 nanoparticles in human mesenchymal stem cells assessed by synchrotron radiation-based techniques.

    PubMed

    Tian, Fei; Chen, Guangcun; Yi, Peiwei; Zhang, Jichao; Li, Aiguo; Zhang, Jing; Zheng, Lirong; Deng, Zongwu; Shi, Qin; Peng, Rui; Wang, Qiangbin

    2014-08-01

    Superparamagnetic iron oxide nanoparticles (SPIOs) have been widely used as the magnetic resonance imaging (MRI) contrast agent in biomedical studies and clinical applications, with special interest recently in in vivo stem cell tracking. However, a full understanding of the fate of SPIOs in cells has not been achieved yet, which is particularly important for stem cells since any change of the microenvironment may disturb their propagation and differentiation behaviors. Herein, synchrotron radiation-based X-ray fluorescence (XRF) in combination with X-ray absorption spectroscopy (XAS) were used to in situ reveal the fate of Fe3O4 and Fe3O4@SiO2 NPs in human mesenchymal stem cells (hMSCs), in which the dynamic changes of their distribution and chemical speciation were precisely determined. The XAS analysis evidences that Fe3O4 NPs cultured with hMSCs are quite stable and almost keep their initial chemical form up to 14 days, which is contradictory to the previous report that Fe3O4 NPs were unstable in cell labeling assessed by using a simplified lysosomal model system. Coating with a SiO2 shell, Fe3O4@SiO2 NPs present higher stability in hMSCs without detectable changes of their chemical form. In addition, XRF analysis demonstrates that Fe3O4@SiO2 NPs can label hMSCs in a high efficiency manner and are solely distributed in cytoplasm during cell proliferation, making it an ideal probe for in vivo stem cell tracking. These findings with the help of synchrotron radiation-based XAS and XRF improve our understanding of the fate of SPIOs administered to hMSCs and will help the future design of SPIOs for safe and efficient stem cells tracking. PMID:24814428

  11. Click chemistry: a new facile and efficient strategy for the preparation of Fe3O4 nanoparticles covalently functionalized with IDA-Cu and their application in the depletion of abundant protein in blood samples

    NASA Astrophysics Data System (ADS)

    Jian, Guiqin; Liu, Yuxing; He, Xiwen; Chen, Langxing; Zhang, Yukui

    2012-09-01

    In this study, we report a novel method to synthesize core-shell structured Fe3O4 nanoparticles (NPs) covalently functionalized with iminodiacetic acid (IDA) via click chemistry between the azide and alkyne groups and charged with Cu2+. Firstly, the Fe3O4@SiO2 NPs were obtained using tetraethoxysilane (TEOS) to form a silica shell on the surface of the Fe3O4 core. The azide group-modified Fe3O4@SiO2 NPs were obtained by a sol-gel process using 3-azidopropyltriethoxysilane (AzPTES) as the silane agent. Fe3O4@SiO2-N3 was directly reacted with N-propargyl iminodiacetic via click chemistry, in the presence of a Cu(I) catalyst, to acquire the IDA-modified Fe3O4 NPs. Finally, through the addition of Cu2+, the Fe3O4@SiO2-IDA-Cu NP product was obtained. The morphology, structure and composition of the NPs were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The resulting NPs showed a strong magnetic response to an externally applied magnetic field, a high adsorption capacity and excellent specificity towards hemoglobin (Hb). In addition, the Fe3O4@SiO2-IDA-Cu NPs can be used for the selective removal of abundant Hb protein in bovine and human blood samples.

  12. Magnetic and rheological properties of monodisperse Fe 3O 4 nanoparticle/organic hybrid

    NASA Astrophysics Data System (ADS)

    Hayashi, Koichiro; Sakamoto, Wataru; Yogo, Toshinobu

    2009-03-01

    Fe 3O 4 nanoparticle/organic hybrids were synthesized via hydrolysis using iron (III) acetylacetonate at ˜80 °C. The synthesis of Fe 3O 4 was confirmed by X-ray diffraction, selected-area diffraction, and X-ray photoelectron spectroscopy. Fe 3O 4 nanoparticles in the organic matrix had diameters ranging from 7 to 13 nm depending on the conditions of hydrolysis. The saturation magnetization of the hybrid increased with an increase in the particle size. When the hybrid contained Fe 3O 4 particles with a size of less than 10 nm, it exhibited superparamagnetic behavior. The blocking temperature of the hybrid containing Fe 3O 4 particles with a size of 7.3 nm was 200 K, and it increased to 310 K as the particle size increased to 9.1 nm. A hybrid containing Fe 3O 4 particles of size greater than 10 nm was ferrimagnetic, and underwent Verwey transition at 130 K. Under a magnetic field, a suspension of the hybrid in silicone oil revealed the magnetorheological effect. The yield stress of the fluid was dependent on the saturation magnetization of Fe 3O 4 nanoparticles in the hybrid, the strength of the magnetic field, and the amount of the hybrid.

  13. Synthesis of Fe3O4@phenol formaldehyde resin core-shell nanospheres loaded with Au nanoparticles as magnetic FRET nanoprobes for detection of thiols in living cells.

    PubMed

    Yang, Ping; Xu, Qi-Zhi; Jin, Sheng-Yu; Zhao, Yang; Lu, Yang; Xu, Xue-Wei; Yu, Shu-Hong

    2012-01-23

    A magnetic, sensitive, and selective fluorescence resonance energy transfer (FRET) probe for detection of thiols in living cells was designed and prepared. The FRET probe consists of an Fe(3)O(4) core, a green-luminescent phenol formaldehyde resin (PFR) shell, and Au nanoparticles (NPs) as FRET quenching agent on the surface of the PFR shell. The Fe(3)O(4) NPs were used as the core and coated with green-luminescent PFR nanoshells by a simple hydrothermal approach. Au NPs were then loaded onto the surface of the PFR shell by electric charge absorption between Fe(3)O(4)@PFR and Au NPs after modifying the Fe(3)O(4)@PFR nanocomposites with polymers to alter the charge of the PFR shell. Thus, a FRET probe can be designed on the basis of the quenching effect of Au NPs on the fluorescence of Fe(3)O(4)@PFR nanocomposites. This magnetic and sensitive FRET probe was used to detect three kinds of primary biological thiols (glutathione, homocysteine, and cysteine) in cells. Such a multifunctional fluorescent probe shows advantages of strong magnetism for sample separation, sensitive response for sample detection, and low toxicity without injury to cellular components. PMID:22190410

  14. A Facile Solvothermal Synthesis of Octahedral Fe3O4 Nanoparticles

    SciTech Connect

    Ooi, Frances; DuChene, Joseph S.; Qiu, Jianqing; Graham, Jeremy O.; Engelhard, Mark H.; Cao, Guixin; Gai, Zheng; Wei, Wei

    2015-06-01

    Magnetic nanoparticles are of great technological interest because they promise numerous potential opportunities in biomedicine and data storage. Although intriguing, these applications require exquisite control over nanostructure morphology in order to appropriately harness their magnetic properties. Most synthesis strategies reported to date are unable to routinely produce anisotropic Fe3O4 nanostructures with appropriate sizes to enable integration into biological systems. Here, we report a simple solvothermal synthesis for obtaining octahedral Fe3O4 nanoparticles with suitable sizes for cellular internalization. Furthermore, these ferromagnetic Fe3O4 octahedrons exhibit substantial saturation magnetization with minimal remanence, suggesting their potential applicability for a host of biomedical applications.

  15. ortho-Phenylenediamine: an effective spacer to build highly magnetic Fe3O4/Au nanocomposites.

    PubMed

    Zhao, Xinmei; Hosmane, Narayan S; Wu, Aiguo

    2012-12-21

    1,2-Diaminobenzene, popularly known as ortho-phenylenediamine (PDA), is found to be a prototype spacer for the deposition of gold nanoparticles on the surfaces of Fe(3)O(4) microspheres. Upon carbonization with PDA, the morphology of the product changes significantly, and the resulting nanocomposites exhibit enhanced magnetism beyond the saturation value of Fe(3)O(4). The Fe(3)O(4)/Au nanocomposites show good surface-enhanced Raman spectroscopy activity with a detection limit of 10(-15)  M. PMID:23143847

  16. The post-spinel transition in Fe3O4-Fe2SiO4 and Fe3O4- FeCr2O4 solid solutions

    NASA Astrophysics Data System (ADS)

    Woodland, Alan; Schollenbruch, Klaus; Frost, Daniel; Langenhorst, Falko

    2010-05-01

    Minerals with spinel structure are important phases in the Earth's mantle. Both magnetite (mt, Fe3O4) and chromite (chr, FeCr2O4) are known to transform to denser orthorhombic post-spinel phases at pressures≥10 GPa and ≥12.5 GPa, respectively (Schollenbruch et al. 2009a; Chen et al. 2003). On the other hand, Fe2SiO4 decomposes to its constituent oxides, FeO and SiO2 at high P and no post-spinel polymorph appears to be stable (e.g. Ito & Takahashi 1989). An important question is how spinel solid solutions behave at high pressures and temperatures since such compositions are arguably more petrologically relevant. In addition, since h-Fe3O4 is apparently not quenchable, it is difficult to investigate its structure. In contrast, two high-P polymorphs of FeCr2O4-rich compositions have been found in a meteorite (Chen et al. 2003), suggesting that the addition of Cr might allow us to recover the post-spinel phase of Fe3O4-bearing compositions from experiments. Building on recent results for the Fe3O4 end member (Schollenbruch et al. 2009a, 2009b), we have begun a study of the high-pressure behaviour of solid solutions along the Fe3O4 -Fe2SiO4 and Fe3O4- FeCr2O4 joins. Multianvil experiments were performed at 10 and 13 GPa and 1200-1300°C on pre-synthesised spinels with compositions 85mt-15 Fe2SiO4, 50mt-50chr and 80mt-20chr. For the Si-bearing experiments, stishovite was present in the run products. This occurrence, along with observed twinning in the Fe-oxide phase (Schollenbruch et al. 2009a) allows us to conclude that the original spinel had transformed to a high-P polymorph at a pressure and that Si is essentially excluded from this new structure. However, the powder XRD data from the run products could not be indexed either to magnetite (spinel structure) or to any other expected phase, including the known post-spinel structures. Interestingly, these are the same reflections reported by Koch et al. (2004) for an unidentified phase in their high-P (> 9 GPa

  17. Nanostructured graphene/Fe3O4 incorporated polyaniline as a high performance shield against electromagnetic pollution

    NASA Astrophysics Data System (ADS)

    Singh, Kuldeep; Ohlan, Anil; Pham, Viet Hung; Balasubramaniyan, R.; Varshney, Swati; Jang, Jinhee; Hur, Seung Hyun; Choi, Won Mook; Kumar, Mukesh; Dhawan, S. K.; Kong, Byung-Seon; Chung, Jin Suk

    2013-02-01

    The development of high-performance shielding materials against electromagnetic pollution requires mobile charge carriers and magnetic dipoles. Herein, we meet the challenge by building a three-dimensional (3D) nanostructure consisting of chemically modified graphene/Fe3O4(GF) incorporated polyaniline. Intercalated GF was synthesized by the in situ generation of Fe3O4 nanoparticles in a graphene oxide suspension followed by hydrazine reduction, and further in situ polymerization with aniline to form a polyaniline composite. Spectroscopic analysis demonstrates that the presence of GF hybrid structures facilitates strong polarization due to the formation of a solid-state charge-transfer complex between graphene and polyaniline. This provides proper impedance matching and higher dipole interaction, which leads to the high microwave absorption properties. The higher dielectric loss (ε'' = 30) and magnetic loss (μ'' = 0.2) contribute to the microwave absorption value of 26 dB (>99.7% attenuation), which was found to depend on the concentration of GF in the polyaniline matrix. Moreover, the interactions between Fe3O4, graphene and polyaniline are responsible for superior material characteristics, such as excellent environmental (chemical and thermal) degradation stability and good electric conductivity (as high as 260 S m-1).

  18. Extraction of organophosphorus pesticides by carbon-coated Fe3 O4 nanoparticles through response surface experimental design.

    PubMed

    Maddah, Bozorgmehr; Alidadi, Sattar; Hasanzadeh, Mahdi

    2016-01-01

    In this paper, carbon-coated Fe3 O4 nanoparticles were successfully synthesized and used as a magnetic solid-phase extraction absorbent for the preconcentration and extraction of organophosphorus pesticides in environmental water samples. The carbon-coated Fe3 O4 nanoparticles were characterized by transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. The determination of organophosphorus pesticides in water samples with carbon-coated Fe3 O4 nanoparticles was investigated by high-performance liquid chromatography with a diode array detector. Furthermore, the response surface model based on the central composite design was applied to quantitatively investigate the effect of some important variables influencing the extraction efficiency, such as pH, treatment time, amount of nanoparticle sorbents, and amount of salt and to find the optimized conditions providing the highest extraction efficiency. Under optimized conditions, the calibration curve was linear in the range of 0.5-15.0 ng/mL with a regression coefficient of 0.9948, 0.9958, and 0.9931 for fenitrothion, diazinon, and ethion, respectively. The obtained results showed that this analytical method would be useful for the analysis of fenitrothion, diazinon, and ethion in tap water with high precision and accuracy. PMID:26519201

  19. Comparative Study of Biosafety, DNA, and Chromosome Damage of Different-Materials-Modified Fe3O4 in Rats.

    PubMed

    Xia, Dong-Lin; Chen, Yan-Pei; Chen, Chao; Wang, Yu-Fei; Li, Xiao-dong; He, Hong; Gu, Hai-Ying

    2015-11-01

    The increasing use of modified Fe3O4 magnetic microparticles has raised safety concerns regarding their use and effect on human health. This study assessed the in vivo biosafety, DNA, and chromosome damage of modified Fe3O4 microparticles such as Au@Fe3O4, Ag@Fe3O4, Cs@Fe3O4, Pt@Fe3O4, and CdS@Fe3O4, using spleen-deficient rats. Spleen-deficient rats treated with naked and modified (Au, Cs, Pt) Fe3O4 microparticles (5000 mg/kg) displayed low toxicity. Only treatment with Cds@Fe3O4 resulted in elevated toxicity and death in rats. Au-, Ag-, and Pt-modified Fe3O4 increased the rate of hemolysis in rats relative to treatment with naked Fe3O4. Despite this, Au- and Pt-modified Fe3O4 increased the biocompatibility and reduced DNA and chromosome damage in rats relative to naked Fe3O4. While Cs@Fe3O4 microparticles displayed a higher biocompatibility than naked Fe3O4, they displayed no significant reduction in DNA and chromosome damage. In summary, Au and Pt surface-modified Fe3O4 microparticles display elevated in vivo biosafety compared to unmodified particles. The precious metal material, with good biological compatibility, surface modification of Fe3O4 is an effective strategy to improve the overall safety and potential therapeutic utility of these magnetic materials. PMID:26329888

  20. Aptamer-conjugated bio-bar-code Au-Fe3O4 nanoparticles as amplification station for electrochemiluminescence detection of tumor cells.

    PubMed

    Chen, Min; Bi, Sai; Jia, Xiaoqiang; He, Peng

    2014-07-21

    An electrochemiluminescence (ECL) assay has been developed for highly sensitive and selective detection of tumor cells based on cell-SELEX aptamer-target cell interactions through a cascaded amplification process by using bio-bar-code Au-Fe3O4 as amplification station. Firstly, bio-bar-code toehold-aptamer/DNA primer/Au-Fe3O4 (TA/DP/Au-Fe3O4) nanoconjugates are fabricated with a ratio of 1:10 to efficiently avoid cross-linking reaction and recognize target cells, which are immobilized on the substrate by hybridizing aptamer to capture probe with 18-mer. Through strand displacement reaction (SDR), the TA/DP/Au-Fe3O4 composites further act as the amplification station to initiate rolling circle amplification (RCA). As a result, on the surface of TA/DP/Au-Fe3O4, a large number of Ru(bpy)2(dcbpy)NHS-labeled probes hybridize to RCA products, which are easily trapped by magnetic electrode to perform the magnetic particle-based ECL platform. Under isothermal conditions, this powerful amplification strategy permits detection of Ramos cells as low as 16 cells with an excellent selectivity. Moreover, analysis of Ramos cells in complex samples and whole blood samples further show the great potential of this ultrasensitive approach in clinical application involving cancer cells-related biological processes. PMID:25000857

  1. Au nanoparticles grafted on Fe3O4 as effective SERS substrates for label-free detection of the 16 EPA priority polycyclic aromatic hydrocarbons.

    PubMed

    Du, Jingjing; Xu, Jianwei; Sun, Zhenli; Jing, Chuanyong

    2016-04-01

    Several methods and materials have been explored for the sensitive and practicable detection of polycyclic aromatic hydrocarbons (PAHs). However, it is still a challenge to develop simple and cost-effective sensing techniques for PAHs. Herein we report the synthesis and construction of Fe3O4@Au SERS substrate. This magnetic substrate was composed by Fe3O4 microspheres and Au NPs. The size, morphology, and surface composition of Fe3O4@Au were characterized by multiple complimentary techniques including scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray powder diffraction. The spatial distributions of electro-magnetic field enhancement around Fe3O4@Au was calculated using finite difference time domain (FDTD) simulations. As a result of its remarkable sensitivity, the Fe3O4@Au-based SERS assay has been applied to detect the 16 EPA priority PAHs. The LODs achieved by our method (100-5 nM, 16.6-1.01 μg L(-1)) make it promising for the rapid screening of highly contaminated cases. As a proof-of-concept study, the substrate was applied in SERS sensing of PAHs in river matrix. The 16 PAHs could be differentiated based upon their characteristic SERS peaks. Most importantly, the detection was successfully conducted using a portable Raman spectrometer, which could be used for on-site monitoring of PAHs. PMID:26995643

  2. Multifunctional Fe3O4 @ Au core/shell nanostars: a unique platform for multimode imaging and photothermal therapy of tumors.

    PubMed

    Hu, Yong; Wang, Ruizhi; Wang, Shige; Ding, Ling; Li, Jingchao; Luo, Yu; Wang, Xiaolin; Shen, Mingwu; Shi, Xiangyang

    2016-01-01

    We herein report the development of multifunctional folic acid (FA)-targeted Fe3O4 @ Au nanostars (NSs) for targeted multi-mode magnetic resonance (MR)/computed tomography (CT)/photoacoustic (PA) imaging and photothermal therapy (PTT) of tumors. In this present work, citric acid-stabilized Fe3O4/Ag composite nanoparticles prepared by a mild reduction route were utilized as seeds and exposed to the Au growth solution to induce the formation of Fe3O4 @ Au core/shell NSs. Followed by successive decoration of thiolated polyethyleneimine (PEI-SH), FA via a polyethylene glycol spacer, and acetylation of the residual PEI amines, multifunctional Fe3O4 @ Au NSs were formed. The designed multifunctional NSs possess excellent colloidal stability, good cytocompatibility in a given concentration range, and specific recognition to cancer cells overexpressing FA receptors. Due to co-existence of Fe3O4 core and star-shaped Au shell, the NSs can be used for MR and CT imaging of tumors, respectively. Likewise, the near infrared plasmonic absorption feature also enables the NSs to be used for PA imaging and PTT of tumors. Our study clearly demonstrates a unique theranostic nanoplatform that can be used for high performance multi-mode imaging-guided PTT of tumors, which may be extendable for theranostics of different diseases in translational medicine. PMID:27325015

  3. 1D Magnetic Materials of Fe3O4 and Fe with High Performance of Microwave Absorption Fabricated by Electrospinning Method

    PubMed Central

    Han, Rui; Li, Wei; Pan, Weiwei; Zhu, Minggang; Zhou, Dong; Li, Fa-shen

    2014-01-01

    Fe3O4 and Fe nanowires are successfully fabricated by electrospinning method and reduction process. Wiry microstructures were achieved with the phase transformation from α-Fe2O3 to Fe3O4 and Fe by partial and full reduction, while still preserving the wire morphology. The diameters of the Fe3O4 and Fe nanowires are approximately 50–60 nm and 30–40 nm, respectively. The investigation of microwave absorption reveals that the Fe3O4 nanowires exhibit excellent microwave absorbing properties. For paraffin-based composite containing 50% weight concentration of Fe3O4 nanowires, the minimum reflection loss reaches −17.2 dB at 6.2 GHz with the matching thickness of 5.5 mm. Furthermore, the calculation shows that the modulus of the ratio between the complex permittivity and permeability |ε/μ| is far away from unity at the minimum reflection loss point, which is quite different from the traditional opinions. PMID:25510415

  4. Multifunctional Fe3O4 @ Au core/shell nanostars: a unique platform for multimode imaging and photothermal therapy of tumors

    PubMed Central

    Hu, Yong; Wang, Ruizhi; Wang, Shige; Ding, Ling; Li, Jingchao; Luo, Yu; Wang, Xiaolin; Shen, Mingwu; Shi, Xiangyang

    2016-01-01

    We herein report the development of multifunctional folic acid (FA)-targeted Fe3O4 @ Au nanostars (NSs) for targeted multi-mode magnetic resonance (MR)/computed tomography (CT)/photoacoustic (PA) imaging and photothermal therapy (PTT) of tumors. In this present work, citric acid-stabilized Fe3O4/Ag composite nanoparticles prepared by a mild reduction route were utilized as seeds and exposed to the Au growth solution to induce the formation of Fe3O4 @ Au core/shell NSs. Followed by successive decoration of thiolated polyethyleneimine (PEI-SH), FA via a polyethylene glycol spacer, and acetylation of the residual PEI amines, multifunctional Fe3O4 @ Au NSs were formed. The designed multifunctional NSs possess excellent colloidal stability, good cytocompatibility in a given concentration range, and specific recognition to cancer cells overexpressing FA receptors. Due to co-existence of Fe3O4 core and star-shaped Au shell, the NSs can be used for MR and CT imaging of tumors, respectively. Likewise, the near infrared plasmonic absorption feature also enables the NSs to be used for PA imaging and PTT of tumors. Our study clearly demonstrates a unique theranostic nanoplatform that can be used for high performance multi-mode imaging-guided PTT of tumors, which may be extendable for theranostics of different diseases in translational medicine. PMID:27325015

  5. Multifunctional Fe3O4 @ Au core/shell nanostars: a unique platform for multimode imaging and photothermal therapy of tumors

    NASA Astrophysics Data System (ADS)

    Hu, Yong; Wang, Ruizhi; Wang, Shige; Ding, Ling; Li, Jingchao; Luo, Yu; Wang, Xiaolin; Shen, Mingwu; Shi, Xiangyang

    2016-06-01

    We herein report the development of multifunctional folic acid (FA)-targeted Fe3O4 @ Au nanostars (NSs) for targeted multi-mode magnetic resonance (MR)/computed tomography (CT)/photoacoustic (PA) imaging and photothermal therapy (PTT) of tumors. In this present work, citric acid-stabilized Fe3O4/Ag composite nanoparticles prepared by a mild reduction route were utilized as seeds and exposed to the Au growth solution to induce the formation of Fe3O4 @ Au core/shell NSs. Followed by successive decoration of thiolated polyethyleneimine (PEI-SH), FA via a polyethylene glycol spacer, and acetylation of the residual PEI amines, multifunctional Fe3O4 @ Au NSs were formed. The designed multifunctional NSs possess excellent colloidal stability, good cytocompatibility in a given concentration range, and specific recognition to cancer cells overexpressing FA receptors. Due to co-existence of Fe3O4 core and star-shaped Au shell, the NSs can be used for MR and CT imaging of tumors, respectively. Likewise, the near infrared plasmonic absorption feature also enables the NSs to be used for PA imaging and PTT of tumors. Our study clearly demonstrates a unique theranostic nanoplatform that can be used for high performance multi-mode imaging-guided PTT of tumors, which may be extendable for theranostics of different diseases in translational medicine.

  6. Multifunctional nanocomposites of Fe3O4-graphene-Au for repeated use in simultaneous adsorption, in situ SERS detection and catalytic reduction of 4-nitrophenol in water

    NASA Astrophysics Data System (ADS)

    Chen, Fenghua; Wang, Yongwei; Chen, Qingtao; Han, Lifeng; Chen, Zhijun; Fang, Shaoming

    2014-12-01

    This work is directed towards the synthesis of a ternary nanocomposite of Fe3O4-graphene-Au, i.e. Fe3O4 nanoparticles (˜300 nm in size) and Au nanoparticles (˜50 nm in size) loaded on the carbon basal planes of reduced graphene oxide, aimed for repeated use in simultaneous adsorption, in situ SERS detection and catalytic reduction of 4-nitrophenol (4-NP) in water, and also for recovering the useful reduction product of 4-aminophenol (4-AP). The results indicate that the amount of 4-NP and 4-AP absorbed to the prepared Fe3O4-graphene-Au nanocomposite can reach 170 mg g-1 and 447 mg g-1, respectively. The reduction reaction of 4-NP to 4-AP by NaBH4 with the Fe3O4-graphene-Au nanocomposite as a catalyst follows first-order kinetics with a rate constant (k) of about 0.4964 min-1, remarkably superior to the 0.1199 min-1 for the reduction reaction with the bare Au nanoparticles under the same conditions. In addition, in situ SERS can also be carried out to detect 4-NP and to monitor the reduction reaction with Fe3O4-graphene-Au as the substrate. Recycling of the composite can be achieved by simply applying an external magnetic field and the results demonstrate that it can be reused at least eight times with almost unaffected catalytic efficiency.

  7. The synthesis and characterization of monodispersed chitosan-coated Fe3O4 nanoparticles via a facile one-step solvothermal process for adsorption of bovine serum albumin.

    PubMed

    Shen, Mao; Yu, Yujing; Fan, Guodong; Chen, Guang; Jin, Ying Min; Tang, Wenyuan; Jia, Wenping

    2014-01-01

    Preparation of magnetic nanoparticles coated with chitosan (CS-coated Fe3O4 NPs) in one step by the solvothermal method in the presence of different amounts of added chitosan is reported here. The magnetic property of the obtained magnetic composite nanoparticles was confirmed by X-ray diffraction (XRD) and magnetic measurements (VSM). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) allowed the identification of spherical nanoparticles with about 150 nm in average diameter. Characterization of the products by Fourier transform infrared spectroscopy (FTIR) demonstrated that CS-coated Fe3O4 NPs were obtained. Chitosan content in the obtained nanocomposites was estimated by thermogravimetric analysis (TGA). The adsorption properties of the CS-coated Fe3O4 NPs for bovine serum albumin (BSA) were investigated under different concentrations of BSA. Compared with naked Fe3O4 nanoparticles, the CS-coated Fe3O4 NPs showed a higher BSA adsorption capacity (96.5 mg/g) and a fast adsorption rate (45 min) in aqueous solutions. This work demonstrates that the prepared magnetic nanoparticles have promising applications in enzyme and protein immobilization. PMID:24994954

  8. Tailor-made magnetic Fe3O4@mTiO2 microspheres with a tunable mesoporous anatase shell for highly selective and effective enrichment of phosphopeptides.

    PubMed

    Ma, Wan-Fu; Zhang, Ying; Li, Lu-Lu; You, Li-Jun; Zhang, Peng; Zhang, Yu-Ting; Li, Ju-Mei; Yu, Meng; Guo, Jia; Lu, Hao-Jie; Wang, Chang-Chun

    2012-04-24

    Selective enrichment of phosphoproteins or phosphopeptides from complex mixtures is essential for MS-based phosphoproteomics, but still remains a challenge. In this article, we described an unprecedented approach to synthesize magnetic mesoporous Fe(3)O(4)@mTiO(2) microspheres with a well-defined core/shell structure, a pure and highly crystalline TiO(2) layer, high specific surface area (167.1 m(2)/g), large pore volume (0.45 cm(3)/g), appropriate and tunable pore size (8.6-16.4 nm), and high magnetic susceptibility. We investigated the applicability of Fe(3)O(4)@mTiO(2) microspheres in a study of the selective enrichment of phosphopeptides. The experiment results demonstrated that the Fe(3)O(4)@mTiO(2) possessed remarkable selectivity for phosphopeptides even at a very low molar ratio of phosphopeptides/non-phosphopeptides (1:1000), large enrichment capacity (as high as 225 mg/g, over 10 times as that of the Fe(3)O(4)@TiO(2) microspheres), extreme sensitivity (the detection limit was at the fmol level), excellent speed (the enrichment can be completed in less than 5 min), and high recovery of phosphopeptides (as high as 93%). In addition, the high magnetic susceptibility allowed convenient separation of the target peptides by magnetic separation. These outstanding features give the Fe(3)O(4)@mTiO(2) composite microspheres high benefit for mass spectrometric analysis of phosphopeptides. PMID:22452444

  9. Crystal structures and magnetic properties of magnetite (Fe3O4)/Polyvinyl alcohol (PVA) ribbon

    NASA Astrophysics Data System (ADS)

    Ardiyanti, Harlina; Suharyadi, Edi; Kato, Takeshi; Iwata, Satoshi

    2016-04-01

    Ribbon of magnetite (Fe3O4)/Polyvinyl Alcohol (PVA) nanoparticles have been successfully fabricated with various concentration of PVA synthesized by co-precipitation method. Particle size of nanoparticles Fe3O4 sample and ribbon Fe3O4/PVA 25% sample is about 9.34 nm and 11.29 nm, respectively. The result of Vibrating Sample Magnetometer (VSM) showed that saturation magnetization value decreased from 76.99 emu/g to 15.01 emu/g and coercivity increased from 49.30 Oe to 158.35 Oe as increasing concentration of PVA. Atomic Force Microscopy (AFM) analysis showed that encapsulated PVA given decreasing agglomeration, controlled shape of nanoparticles Fe3O4 more spherical and dispersed. Surface roughness decreased with increasing concentration of PVA.

  10. Magnetically Separable Fe3O4@DOPA-Pd: A Heterogeneous Catalyst for Aqueous Heck Reaction

    EPA Science Inventory

    Magnetically separable Fe3O4@DOPA-Pd catalyst has been synthesized via anchoring of palladium over dopamine-coated magnetite via non-covalent interaction and the catalyst is utilized for expeditious Heck coupling in aqueous media.