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1.
In this work, a simple and green method is used to fabricate magnet nanocomposite microspheres (cellulose/chitosan/Fe3O4) based on cellulose/chitosan microsphere via the interaction between metal ions with chitosan. The results of Fourier transform infrared spectra and X-ray diffraction indicated that the Fe3O4 nanoparticles were well-fixed in the network of cellulose/chitosan microsphere as a result of the chelation role between chitosan and metal ions. Moreover, the morphology of Fe3O4 nanoparticle can be adjusted by changing the chitosan concentration of cellulose/chitosan microsphere. Most important, the catalytic performance of the nanocomposite magnet microsphere was studied, and the magnet nanocomposite microspheres with face-centered cubic structure and less size of Fe3O4 nanoparticles have shown excellent catalytic performance. Based on their excellent catalytic properties, these magnet cellulose/chitosan/Fe3O4 microspheres have prospect applications in the field of biotechnology and environmental, and so on.  相似文献   

2.
In this work, magnetically separable Fe3O4 nanoparticles were synthesized in the presence of natural κ-carrageenan (KCAR) biopolymer to provide Fe3O4@KCAR. FT-IR analysis, scanning electron microscopy (SEM), X-ray diffraction, VSM analysis, and SEM-EDAX were incorporated for the characterization of Fe3O4@KCAR nanocomposite. And then, the first catalytic report of Fe3O4@KCAR with no post-modification was achieved by studying its catalytic activity in the multicomponent reaction of rhodanine synthesis. Based on this study, Fe3O4@KCAR was an efficient, magnetically separable and recyclable, water-dispersible and green catalyst with natural source. This catalyst also showed 9-run recyclability with no significant yield decrease.  相似文献   

3.
In this research, novel ternary Ag/αFe2O3-rGO nanocomposites with various contents of GO were synthesized via a facile one-pot hydrothermal method. Ag/αFe2O3-rGO nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrometer (EDX), photoluminescence (PL) spectroscopy, and Fourier transform infrared (FTIR). The results showed that hematite nanoparticles and Ag nanoparticles were well decorated on the graphene surface. Photocatalytic activity of Ag/αFe2O3-rGO ternary nanocomposites and pure Ag/αFe2O3 was investigated for photodegradation of Congo red dye solution as a model pollutant under UV light irradiation. The ternary nanocomposite with 1.8?mg/ml GO aqueous solution concentration shows higher degradation efficiency under UV light irradiation than the pure Ag/αFe2O3 and the nanocomposites with other GO aqueous solution concentrations. It was observed that the adsorption of the dyes on the nanocomposites surface is dependent on the graphene content due to a decrease in the recombination rate, particles size, and increase charge carrier transfer. The results show that the Ag/αFe2O3-rGO nanocomposite can be used as an excellent photocatalytic material for degradation of Congo red dye in wastewater. A possible photocatalytic mechanism was proposed for degradation of Congo red dye.  相似文献   

4.
Ultrasonically initiated miniemulsion polymerization of styrene was conducted in the presence of Fe3O4 nanoparticles. Stable polystyrene (PS)/Fe3O4 nanocomposite emulsions were prepared and magnetic PS/Fe3O4 composite particles were obtained through magnetic separation. The whole procedure comprised two steps. First, Fe3O4 nanoparticles were dispersed in the monomer phase with the aid of stabilizer Span‐80. Second, miniemulsion polymerization of styrene in the presence of Fe3O4 nanoparticles was carried out under an ultrasonic field in the absence of a chemical initiator. The affecting factors, including stabilizer concentration, surfactant concentration, hexadecane concentration and the amount of Fe3O4, were systematically studied. Stabilizer concentration, surfactant concentration and hexadecane concentration strongly affected the formation of the coagulation. The least amount of coagulation was formed at 2.5 wt% Span‐80 concentration. The addition of Fe3O4 nanoparticles drastically increased the polymerization rate owing to the fact that Fe3O4 nanoparticles increased the acoustic intensity and Fe2+ reacted with H2O2 to produce hydroxyl radicals and increase the number of radicals. The increase in cosurfactant concentration and power output also increased the polymerization rate. Copyright © 2005 Society of Chemical Industry  相似文献   

5.
Silver nanoparticles supported on superparamagnetic iron oxide (SPION)-Tween20 nanocomposite were prepared by a combined polyol and chemical reduction routes. The morphology, composition and structure of Fe3O4@Tween20@Ag nanocatalyst were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy, energy dispersive X-ray spectroscopy, thermal gravimetric analyzer, and X-ray powder diffraction. In addition the magnetic properties were evaluated with vibrating sample magnetometry. It was found that Fe3O4@Tween20@Ag nanocatalyst could catalyze the degradation of various organic azo dyes and could easily be recovered from the reaction medium with external magnet. Also, the magnetic catalyst can be succesfully recycled and reused for at least five successive degradation cycles of methyl orange, methylene blue and Rhodamine B, confirming a high recycling efficiency. The cost effective and recyclable Fe3O4@Tween20@Ag nanocatalyst provide an novel nanomaterials architecture for environmental remediation applications.  相似文献   

6.
Hollow polyaniline/Fe3O4 microsphere composites with electromagnetic properties were successfully prepared by decorating the surface of hollow polyaniline/sulfonated polystyrene microspheres with various amounts of Fe3O4 magnetic nanoparticles using sulfonated polystyrene (SPS) as hard templates and then removing the templates with tetrahydrofuran (THF). The synthesized hollow microsphere composites were characterized by FT-IR, UV/Vis spectrophotometry, SEM, XRD, elemental analysis, TGA, and measurement of their magnetic parameters. Experimental results indicated that the microspheres were well-defined in size (1.50–1.80 μm) and shape, and that they were superparamagnetic with maximum saturation magnetization values of 3.88 emu/g with a 12.37 wt% content of Fe3O4 magnetic nanoparticles. Measurements of the electromagnetic parameters of the samples showed that the maximum bandwidth was 8.0 GHz over ?10 dB of reflection loss in the 2–18 GHz range when the Fe3O4 content in the hollow polyaniline/Fe3O4 microsphere composites was 7.33 wt%.  相似文献   

7.
《Ceramics International》2016,42(9):10682-10689
A ternary nanocomposite of Fe3O4@SnO2/reduced graphene oxide (RGO) with different contents of SnO2 nanoparticles was synthesized by a simple and efficient three-step method. The transmission electron microscopy and field emission scanning electron microscopy characterization display that plenty of Fe3O4@SnO2 core–shell structure nanoparticles are well distributed on the surface of RGO sheets. The X-ray diffractograms show that the products consist of highly crystallized cubic Fe3O4, tetragonal SnO2 and disorderedly stacked RGO sheets. The magnetic hysteresis measurement reveals the ferromagnetic behavior of the products at room temperature. The microwave absorption properties of paraffin containing 50 wt% products were investigated at room temperature in the frequency range of 2–18 GHz by a vector network analyzer. The electromagnetic data show that the maximum reflection loss is −45.5 dB and −29.5 dB for Fe3O4@SnO2/RGO-1 and Fe3O4@SnO2/RGO-2 nanocomposite, respectively. Meanwhile, the reflection loss less than −10 dB is up to 14.4 GHz and 13.8 GHz for Fe3O4@SnO2/RGO-1 and Fe3O4@SnO2/RGO-2 nanocomposite, respectively. It is believed that such nanocomposite could be used as promising microwave absorbers.  相似文献   

8.
Fe3O4-graphene nanocomposite was prepared by a gas/liquid interface reaction. The structure and morphology of the Fe3O4-graphene nanocomposite were characterized by X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy. The electrochemical performances were evaluated in coin-type cells. Electrochemical tests show that the Fe3O4-22.7 wt.% graphene nanocomposite exhibits much higher capacity retention with a large reversible specific capacity of 1048 mAh g−1 (99% of the initial reversible specific capacity) at the 90th cycle in comparison with that of the bare Fe3O4 nanoparticles (only 226 mAh g−1 at the 34th cycle). The enhanced cycling performance can be attributed to the facts that the graphene sheets distributed between the Fe3O4 nanoparticles can prevent the aggregation of the Fe3O4 nanoparticles, and the Fe3O4-graphene nanocomposite can provide buffering spaces against the volume changes of Fe3O4 nanoparticles during electrochemical cycling.  相似文献   

9.
Much attention has been increasingly focused on the applications of noble metal nanoparticles (NPs) for the catalytic degradation of various dyes and pigments in industrial wastewater. We have demonstrated that Pd NPs/Fe3O4-PEI-RGO nanohybrids exhibit high catalytic activity and excellent durability in reductive degradation of MO, R6G, RB. Specific surface area was successfully prepared by simultaneous reduction of Pd(OAc)2 chelating to PEI grafted graphene oxide nanosheets modified with Fe3O4. The as-prepared Pd NPs/Fe3O4-PEI-RGO nanohybrids were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, high-resolution TEM and energy dispersive X-ray spectroscopy, and UV-lambda 800 spectrophotometer, respectively. The catalytic activity of Pd NPs/Fe3O4-PEI-RGO nanohybrids to the degradation of MO, R6G, RB with NaBH4 was tracked by UV-visible spectroscopy. It was clearly demonstrated that Pd NPs/Fe3O4-PEI-RGO nanohybrids exhibited high catalytic activity toward the degradation of dyes and pigments, which could be relevant to the high surface areas of Pd NPs and synergistic effect on transfer of electrons between reduced graphene oxide (RGO), PEI and Pd NPs. Notably, Pd NPs/Fe3O4-PEI-RGO nanohybrids were easily separated and recycled thirteen times without obvious decrease in system. Convincingly, Pd NPs/Fe3O4-PEI-RGO nanohybrids would be a promising catalyst for treating industrial wastewater.  相似文献   

10.
Magnetite decorated carboxylic acid functionalized multi-walled carbon nanotube (MWCNT-Fe3O4) was successfully inserted in polyvinylpyrrolidone (PVP) matrix in the aqueous media, as a result of which magnetic polymer nanocomposite (PVP/MWCNT-Fe3O4) was formed. With application of SEM, the surface morphology of the produced PVP/MWCNT-Fe3O4 nanocomposite was compared with that of pure PVP. The diameter distribution of Fe3O4 decorated carboxylic acid functionalized multi-walled carbon nanotube was determined by image analysis of the SEM micrographs. In addition, the structural and thermal characterizations of PVP/MWCNT-Fe3O4 nanocomposite were performed by FT-IR, XRD, TGA, and DSC techniques. Moreover, magnetic characterization of the prepared nanocomposite was determined by VSM. The obtained results indicated that addition of MWCNT-Fe3O4 (5% w/w) to PVP improved the thermal properties of pure polyvinylpyrrolidone. According to the results of DSC analysis, the glass transition temperature of 160?°C was observed for the PVP/MWCNT-Fe3O4 (5% w/w) nanocomposite. The FT-IR spectra showed that an interaction was taking place between MWCNT-Fe3O4 and PVP. The strong interaction with ~31 cm?1 red shift along with good complexation of carbonyl functional group of PVP with MWCNT-Fe3O4 was observed for PVP/MWCNT-Fe3O4 (5% w/w) nanocomposite as a result of a better distribution of carbon nanotubes in the PVP matrix.  相似文献   

11.
A simple, cost-effective, efficient, and green approach to synthesize iron oxide/graphene (Fe3O4/rGO) nanocomposite using in situ deposition of Fe3O4 nanoparticles on reduced graphene oxide (rGO) sheets is reported. In the redox reaction, the oxidation state of iron(II) is increased to iron(III) while the graphene oxide (GO) is reduced to rGO. The GO peak is not observed in the X-ray diffraction (XRD) pattern of the nanocomposite, thus providing evidence for the reduction of the GO. The XRD spectra do have peaks that can be attributed to cubic Fe3O4. The field emission scanning electron microscopy (FESEM) images show Fe3O4 nanoparticles uniformly decorating rGO sheets. At a low concentration of Fe2+, there is a significant increase in the intensity of the FESEM images of the resulting rGO sheets. Elemental mapping using energy dispersive X-ray (EDX) analysis shows that these areas have a significant Fe concentration, but no morphological structure could be identified in the image. When the concentration of Fe2+ is increased, the Fe3O4 nanoparticles are formed on the rGO sheets. Separation of the Fe3O4/rGO nanocomposite from the solution could be achieved by applying an external magnetic field, thus demonstrating the magnetic properties of the nanocomposite. The Fe3O4 particle size, magnetic properties, and dispersibility of the nanocomposite could be altered by adjusting the weight ratio of GO to Fe2+ in the starting material.  相似文献   

12.
《Ceramics International》2020,46(11):18768-18777
A novel highly efficient photocatalyst composite BiFeO3/Fe3O4 has been synthesized by mechanosynthesis and applied to the degradation of Methylene Blue under visible light. Structural, optical and photocatalytic properties of the proposed photocatalyst composites are carefully investigated. The nanointerfaces, associated to ferrous Fe2+ ions of the Fe3O4 nanoparticles, improve the photocatalytic efficiency when compared with pure BiFeO3 or Fe3O4. The time required to the complete degradation of Methylene Blue solution is 40 min for the sample with 20% of Fe3O4 which is more than 7 times faster than the time required using BiFeO3 alone. Moreover, with the addition of H2O2 a complete degradation is achieved just after 10 min, which is faster than any other photocatalytic reaction reported for BiFeO3-based materials. This enhancement is assumed to be related to an electron drain process due to the difference between energy levels of the conduction bands of BiFeO3 and Fe3O4 combined with the direct Fenton-like process associated with the Fe2+ ions of the composites.  相似文献   

13.
Dark- and photo-Fenton type processes, Fe2+/H2O2, Fe3+/H2O2, Fe0/H2O2, UV/Fe2+/H2O2, UV/Fe3+/H2O2 and UV/Fe0/H2O2, were applied for the treatment of model colored wastewater containing two reactive dyes, C.I. Reactive Blue 49 and C.I. Reactive Blue 137, and degradation kinetics were compared. Dye degradation was monitored by the means of UV/VIS, adsorbable organic halides (AOX) and total organic carbon (TOC) analysis, thus determining decolorization and dechlorination of triazine structure, as well as mineralization of model colored wastewater. Both dark- and photo-Fenton type processes were proven to be very efficient for color removal; ≥98% was achieved in all cases. Significant improvements in the mineralization of studied dyes were achieved by the assistance of UV light, as it was expected. It was demonstrated that the degradation kinetic of applied dyes depended on the presence of UV light, as well as type of iron catalyst and dye structure. On bases of the obtained experimental results, the mathematical models were developed describing dye degradation kinetics in all studied systems. Since UV light was used in order to enhance the efficiency of dark-Fenton type processes, mathematical model describing dye degradation by UV photolysis providing the values of quantum yields for each of the dye was developed and incorporated in model for photo-Fenton type processes. A sensitivity analysis for the evaluation of importance of each reaction used in mathematical models was also performed.  相似文献   

14.
Graphene oxide–Fe2O3 (GO–Fe2O3) hybrid material was synthesized as a heterogeneous catalyst for photo-Fenton degradation of organic contaminants by an easy and scalable impregnation. X-ray diffraction analysis and high-resolution transmission electron microscope analysis confirm the existence of the Fe2O3 nanoparticles in the GO–Fe2O3 catalyst. Fourier transform infrared spectroscopy analysis proves that the combination of Fe2O3 and GO sheet is due to the metal–carbonyl coordination. The catalytic activities of the GO–Fe2O3 catalyst were evaluated by the degradation of Rhodamine B and 4-nitrophenol under visible light irradiation (>420 nm) in the presence of hydrogen peroxide. The results show that the catalyst exhibited excellent catalytic property at a wide pH range of 2.09–10.09 and stable catalytic activity after seven recycles, which could be attributed to the synergetic effects of the adsorptive power of GO and the hydroxyl radicals produced by heterogeneous photo-Fenton reactions. The present results suggest that the GO–Fe2O3 hybrid material can act as an efficient heterogeneous catalyst for degradation of organic contaminants, which may provide insight into the design and development of high-efficiency visible-light photocatalyst for water treatment.  相似文献   

15.
《Ceramics International》2022,48(13):18316-18323
Heterocyclic compounds such as spirooxindole, with five rings containing nitrogen, have an important role in the realm of medicine. This study aims to synthesize the spirooxindole derivative compounds using Fe3O4/graphene oxide (GO) nanocomposite as the catalyst. The GO sample was synthesized by Hummers' method, followed by the insertion of Fe3O4 into the graphene oxide layers by the co-precipitation method. Both XRD and FTIR analyses reveal that GO and Fe3O4/GO samples have been successfully formed. SEM-EDX micrograph supported by TEM image indicates that the Fe3O4 nanoparticles in the composite have excellent dispersibility, attributable to the existence of the GO sheets. The evaluation of the ability of Fe3O4/GO as a catalyst in the synthesis of spirooxindole derivatives was carried out by the one-pot three-component method. The reaction yield shows that Fe3O4/GO was a suitable and reusable catalyst in this reaction.  相似文献   

16.
A high surface, magnetic Fe3O4@mesoporouspolyaniline core‐shell nanocomposite was synthesized from magnetic iron oxide (Fe3O4) nanoparticles and mesoporouspolyaniline (mPANI). The novel porous magnetic Fe3O4 was obtained by solvothermal method under sealed pressure reactor at high temperature to achieve high surface area. The mesoporouspolyaniline shell was synthesized by in situ surface polymerization onto porous magnetic Fe3O4 in the presence of polyvinylpyrrolidone (PVP) and sodium dodecylbenzenesulfonate (SDBS), as a linker and structure‐directing agent, through ‘blackberry nanostructures’ assembly. The material composition, stoichiometric ratio and reaction conditions play vital roles in the synthesis of these nanostructures as confirmed by variety of characterization techniques. The role of the mesoporouspolyaniline shell is to stabilize the porous magnetic Fe3O4 nanoparticles, and provide direct access to the core Fe3O4 nanoparticles. The catalytic activity of magnetic Fe3O4@mesoporousPANI nanocomposite was evaluated in the cross‐coupling of aryl chlorides and phenols.  相似文献   

17.
Cellulose nanocomposites containing high contents of Fe3O4 nanoparticles were successfully prepared with regenerated cellulose films as a matrix and mixture solutions of Fe2+/Fe3+ as precursors. The structure and properties of the magnetic nanocomposite films were investigated with X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and vibrating sample magnetometry. Fe3O4 nanoparticles as prepared were irregular spheres and were homogeneously dispersed in the cellulose matrix. With an increase in the concentration of precursors from 0.2 to 1.0 mol/L, the content of Fe3O4 nanoparticles in the dried nanocomposites increased from 12 to 39 wt %, and the particle diameter increased from 32 to 64 nm. The cellulose nanocomposite films demonstrated superparamagnetic behavior, and their saturation magnetizations were in the range 4.2–21.2 emu/g, which were related to the increase in Fe3O4 nanoparticle content. With increasing nanophase content, the nanocomposite films displayed significantly anisotropic magnetic properties in the parallel and perpendicular directions. This study provided a green and facile method for the preparation of biobased nanocomposite films with high nanophase content and excellent magnetic properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

18.
We have synthesized Fe3O4 nanoparticles on mesoporous SBA-15 by an “in situ” approach. The synthesized nanocomposite material was well characterized using wide and low angle XRD, N2 adsorption–desorption isotherm, TEM, FTIR, XPS, and VSM analysis. The Fe3O4@SBA-15 nanocomposite material was used as a magnetically recoverable catalyst (MRC) for three component coupling reaction of aldehyde, amine and alkyne. The reported catalyst was recycled up to five times without significant loss in its catalytic activity.  相似文献   

19.
《Ceramics International》2017,43(12):9226-9234
Transition metal nitrides (TMNs) hold great promises as electrode materials in energy devices like supercapacitors, lithium ion batteries and solar cells. However, the poor electrochemical stability severely limits their real-life applications. In this study, we prepared electrochemically stable Fe2N-TiN nanocomposite with varied TiN contents by the nitridation of oxide precursors by ammonia. The formation mechanism consists of the solid reaction between TiO2 and Fe2O3. A protective sintering (PS) technique has been developed for the first time to fabricate pure Fe2N-TiN nanocomposite ceramics after comparing different sintering methods including spark plasma sintering (SPS). Porous microstructures formed by homogenous distribution of ultrafine TiN nanoparticles within large Fe2N micro-grains skeleton were obtained after sintering. The electrochemical performances of the Fe2N-TiN nanocomposites by PS have been investigated in different electrolytes. The mechanism of charge storage is mainly due to the double layer capacitance. The composites with 15 wt% TiN loading show the highest specific capacitance of 58.4 F g−1 in 7.5 M KOH. Furthermore, excellent cycling stability with zero degradation after 1000 cycles was proved for such nanocomposite electrodes, confirming their potential for energy storage.  相似文献   

20.
《Ceramics International》2023,49(16):26683-26693
In this work, zero-dimensional (0D) high crystalline PrFeO3 worm nanocrystals were loaded over a three-dimensional (3D) rectangular WO3 to construct a 0D/3D PFO/W Z-scheme heterojunction by an in situ ultrasonic synthetic process. This heterojunction exhibited excellent photocatalytic activities towards the degradation of organic pollutants such as rhodamine B (RhB), Methylene blue (MB), and tetracycline hydrochloride (TC) in the presence of small amounts of H2O2 under visible-light irradiation. For example, the k value of PFO/W + H2O2 was about 67, 107, 45, 27, 11 and 14 times higher than pure H2O2, PrFeO3, WO3, PFO/W nanocomposite, PrFeO3+ H2O2 and WO3+H2O2 respectively during the degradation of MB. The trapping experiments and ESR measurements identified that the generated ·OH, ·O2, and h+ were the active species involved in the catalysis. Further, the ·OH radical could be continuously generated by Fe3+/Fe2+ and W6+/W5+ conversion and played the dominant role in the degradation of organic pollutants. The superior photocatalytic performance of the PFO/W + H2O2 system was derived from the synergistic effect of the Z-scheme heterostructure and dual photo-Fenton-like oxidation (Fe3+/Fe2+ and W6+/W5+). A possible mechanism was postulated based on the results obtained. In summary, this study provided new insights into synthesizing an effectively heterogeneous 0D/3D Z-scheme dual photo-Fenton-like catalyst for water clarification.  相似文献   

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