Study of structural and magnetic properties of superparamagnetic Fe3O4/SiO2 core–shell nanocomposites synthesized with hydrophilic citrate-modified Fe3O4 seeds via a sol–gel approach

Farimani, Mitra Helmi Rashid; Shahtahmasebi, N.; Roknabadi, Mahmood Rezaee; Ghows, Narjes; Kazemi, A.

doi:10.1016/j.physe.2013.04.032

Cited by 70 publications

(34 citation statements)

References 30 publications

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“…NPs was found to be 6.8 which is compatible with literature values [8,27,28]. The Fe 3 O 4 @SiO 2 NPs showed an iep of 2.2 close to that of amorphous silica [29] and the iep of Fe 3 O 4 @SiO 2 @L NPs was measured to be 8.4.…”

Section: Adsorption Experimentssupporting

confidence: 89%

“…These results indicate that the magnetite NPs was successfully coated by silica. The wide bands around 3440 cm −1 wavelength are attributed to O-H stretching vibrations of free water molecules, hydroxyl groups (OH) on the surface, or water molecules absorbed by the material [8,9]. TEM images of the NPs were shown in Fig.…”

Section: Adsorption Experimentsmentioning

confidence: 99%

“…Figure 4 shows the XRD pattern of NPs. Large peaks show nanocrystalline and sharp peaks show the high degree of crystalline structure [8,25] Fig. 4b indicate the presence of magnetite crystals.…”

Section: Adsorption Experimentsmentioning

confidence: 99%

“…Furthermore, Fe 3 O 4 NPs are also used for some specific applications, such as drug delivery, magnetic field-assisted cancer therapy, cell labelling and sorting, magnetic resonance imaging and sensing. Like this there are various applications of Fe 3 O 4 NPs, but they are not very stable under different environmental conditions, can turn into maghemite by oxidation and soluble in strongly acidic media [6][7][8][9]. In order to overcome these problems, the surface of Fe 3 O 4 NPs can be layered with a protective material.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, Characterization and Cr(VI) Adsorption Properties of Modified Magnetite Nanoparticles

2017

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In this study, magnetite (Fe3O4) nanoparticles were synthesized by chemical co-precipitation method, coated with silica, and then the surface of silica coated magnetite (Fe3O4@SiO2) nanoparticles was modified with (3-aminopropyl)triethoxysilane (APTES) at first. Secondly, attained nanoparticles were characterized by the Fourier transform infrared, X-ray diffraction, transmission electron microscopy, the Brunauer-Emmett-Teller, vibrating sample magnetometer, and zeta-sizer devices/methods. Finally, detailed adsorption experiments were performed to remove hexavalent chromium (Cr(VI)) from aqueous media by synthesized nanoparticles. Mean size and specific surface area of synthesized nanoparticles were about 15 nm and 89.5 m 2 /g, respectively. The highest adsorption capacity among used adsorbents (Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@L) was attained by Fe3O4 nanoparticles and it was determined that adsorption capacity of the other two adsorbents was too low when compared to the Fe3O4 nanoparticles. Optimum conditions for Cr(VI) adsorption by Fe3O4 nanoparticles were: pH, 3; temperature, 55• C; contact time, 90 min; adsorbent concentration, 0.5 g/l and initial Cr(VI) concentration 10 mg/l. Under these conditions, adsorption capacity and removal percentage of Cr(VI) were found to be 33.45 mg/g and 88%, respectively.

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Section: Adsorption Experimentssupporting

confidence: 89%

Section: Adsorption Experimentsmentioning

confidence: 99%

Section: Adsorption Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis, Characterization and Cr(VI) Adsorption Properties of Modified Magnetite Nanoparticles

2017

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“…The broad peaks indicate that nano-crystalline nature of TiO 2 NPs has formed successfully. The average crystalline size of the NPs in the polymer matrix was calculated using Scherrer's equation [25,26]. Crystalline sizes were calculated for major peaks, i.e.…”

Section: Characterizationmentioning

confidence: 99%

Fabrication and study of UV-shielding and photocatalytic performance of uniform TiO2/SiO2 core-shell nanofibers via single-nozzle co-electrospinning and interface sol–gel reaction

Nakhaei¹,

Shahtahmassebi²,

Roknabadi³

et al. 2016

Scientia Iranica

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Abstract. One-dimensional TiO2/SiO2 core-shell nano bers were fabricated using a single-nozzle co-electrospinning process with phase-separated, mixed polymer composite solution. The core and shell were composed of Polyvinylpyrrolidone (PVP) and Polyacrylonitrile (PAN) polymers with uniform distribution of TiO 2 and SiO 2 nanoparticles (NPs), respectively. The NPs were synthesized via sol-gel reaction, simultaneously, in the respective polymer solutions. The morphologies and structures of the fabricated TiO2/SiO2 core-shell nano bers were investigated by XRD, FTIR, SEM, EDS, and TEM images. The in uences of di erent amounts of TiO2 and SiO2 precursors on the photocatalytic and UVshielding performance of TiO 2 /SiO 2 core-shell nano bers were studied. Photocatalytic activity of the nano bers was evaluated by observing photo-degradation of Methyl Orange (MO) aqueous solution under irradiation of ultraviolet (UV) light. Our results for the TiO 2 /SiO 2 core-shell nano bers indicate good potential for superior applications in photocatalytic and UV shielding devices.

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Preparation of a novel magnetically recoverable copper complex catalyst and its application in the Henry reaction

et al. 2018

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A novel magnetically recoverable copper complex catalyst based on Fe3O4 nanoparticles as a magnetic carrier was successfully synthesized. The catalyst was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, and alternating gradient magnetometry (AGM). The Henry reaction catalyzed by this prepared magnetically recoverable copper complex catalyst proceeded in high yield (97 %) and with high conversion (94 %). The prepared catalyst possesses superparamagnetic properties and can be recycled very conveniently using an external magnetic field. The self‐prepared catalyst has excellent catalytic selectivity and good reusability, making this method a clean and energy‐efficient process.

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Study of structural and magnetic properties of superparamagnetic Fe3O4/SiO2 core–shell nanocomposites synthesized with hydrophilic citrate-modified Fe3O4 seeds via a sol–gel approach

Cited by 70 publications

References 30 publications

Synthesis, Characterization and Cr(VI) Adsorption Properties of Modified Magnetite Nanoparticles

Synthesis, Characterization and Cr(VI) Adsorption Properties of Modified Magnetite Nanoparticles

Fabrication and study of UV-shielding and photocatalytic performance of uniform TiO2/SiO2 core-shell nanofibers via single-nozzle co-electrospinning and interface sol–gel reaction

Preparation of a novel magnetically recoverable copper complex catalyst and its application in the Henry reaction

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