RSC Advances
·
2014
·Vol. 4
·期 84
·44575-44582
·
IF 3.708
Peng Jing,Qin Wang,Baocang Liu,Guangran Xu,Yanbing Zhang,Jun Zhang,Gejihu De
We develop a facile layer-by-layer deposition process to create bi-functional Fe3O4@SiO2@Gd2O3:Yb,Er nanostructures composed of magnetic Fe3O4 cores, variable SiO2 mid-layers, and up-converting Gd2O3 shells. The synthetic process is well-controlled and the obtained Fe3O4@SiO2@Gd2O3:Yb,Er nanoparticles show relative monodispersity and exhibit tunable magnetic and up-conversion luminescence depending on the thickness of SiO2 mid-layers. The influences of SiO2 mid-buffer-layers on morphology, magnetism, and up-conversion luminescence are well addressed. The obtained bi-functional Fe3O4@SiO2@Gd2O3:Yb,Er nanoparticles may be potentially applicable in magnetic, fluorescent, and biological applications. The synthetic route may be employed for fabricating other multifunctional nanostructures.
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ANALYTICA CHIMICA ACTA
·
2015
·
IF 4.513
Zihong Sun,Weihua Wang,Haibin Wen,Cuifen Gan,Hongtao Lei,Yingju Liu
A highly sensitive electrochemical immunoassay of chlorpyrifos (CPF) was developed by using a biocompatible quinone-rich polydopamine nanospheres modified glass carbon electrode as the sensor platform and multi-horseradish peroxidase-flake like Fe 3 O 4 coated carbon nanotube nanocomposites as the signal label. Due to the quinone-rich polydopamine nanospheres, the platform exhibited excellent fixing capacity by simple coating of sticky polydopamine nanospheres and subsequent oxidization. By coprecipitation of Fe 3+ and Fe 2+ on polydopamine modified carbon nanotubes (CNTs) with the aid of ethylene glycol (EG), the flake-like Fe 3 O 4 coated CNTs (CNTs@f-Fe 3 O 4 ) were synthesized and chosen as the carrier of multi-enzyme label due to the high loading of secondary antibody (Ab 2 ) and horseradish peroxidase (HRP) and also the peroxidase-mimic activity of Fe 3 O 4 . Under the optimum conditions, the immunosensor can detect CPF over a wide range with a detection limit of 6.3 pg/mL. Besides, the high specificity, reproducibility and stability of the proposed immunosensor were also proved. The preliminary application in real sample showed good recoveries, indicating it holds promise for fast analysis of CPF in aquatic environment.
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Journal of the Taiwan Institute of Chemical Engineers
·
2015
·
IF 3
Zhongwei
Jiang,Yuanfang Li
Integration of other functional materials onto the surface or into the matrixes of metal-organic frameworks (MOFs) is an attractive and effective approach to fabricate multifunctional MOFs. Herein, we report a facile and novel strategy for in situ synthesis of magnetic hybrid Fe 3 O 4 /MIL-101 via heterogeneous coprecipitation assembly. Characterizations showed that the Fe 3 O 4 nanoparticles were uniformly coated on the outer-surface of MIL-101. The as-synthesized Fe 3 O 4 /MIL-101 composite holds larger BET surfaces area, pore volume and higher positive charge than MIL-101. These preferable properties make it to be an excellent candidate for adsorption and removal of anionic dye from aqueous solution. The present work provides a new insight for in situ synthesis of Fe 3 O 4 -functionalized MOFs, offering an alternative way to prepare magnetic hybrid materials for a wide range of applications.
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RSC Advances
·
2015
·Vol. 5
·期 29
·23039-23045
·
IF 3.84
Weiwei Zhu,Yijing Li,Fang Zeng,Hang Yin,Liyuan Wang,Hao Zhu
Superparamagnetic Fe3O4 nanoparticles with diameter about 18 nm were prepared by a solvothermal method. A simple and green method was used to prepare amino-rich magnetic nanoparticles. The magnetic nanoparticles were modified by polyethylenimine (PEI) which is a polycationic polymer when pH < 10. The resulted magnetic nanoparticles were activated by glutaraldehyde to obtain nanoscale support for Candida rugosa Lipase (CRL) immobilization. The CRL was immobilized on the magnetic nanoparticles covalently, as well as via ionic exchange. The structure and magnetic behavior of the magnetic nanoparticles were confirmed by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM). Then the properties of the immobilized CRL were investigated, and the results showed that the obtained immobilized lipase displayed good reusability and applicability. The immobilized Candida rugosa Lipase (ICRL) presented wider pH tolerance (residual activity > 80% in a pH range from 5.5 to 8.0) than free Candida rugosa Lipase (residual activity decreased rapidly when the pH values were away from 7.0). ICRL showed excellent thermal stability (the relative of ICRL > 90%) after keeping in the water bath at 50 °C for 150 min while free Candida rugosa Lipase (FCRL) was absolutely deactivated. After being reused 10 times, ICRL maintained 60% relative activity.
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Advanced Materials Interfaces
·
2015
·Vol. 3
·期 1
·1500418
·
IF 0
Jun-Wei Zha,Wei Huang,Si-Jiao Wang,Dong-Li Zhang,Robert K. Y. Li,Zhi-Min Dang
Functional materials with excellent electrical and magnetic properties have a potential application in most high-tech fields. Here, superparamagnetic graphene–Fe 3 O 4 (G–F) nanosheet hybrids are prepared by a facile one-step hydrothermal process, which will beneficial to well combine with various polymer matrix to get binary functional composites. Polydimethylsiloxane (PDMS) nanocomposites filled with G–F nanosheets are prepared by a three rolling method. The microstructures of G–F nanosheets as well as the electrical, piezoresistive, and magnetic properties of the G–F/PDMS nanocomposites are investigated. Slightly above the percolation threshold ( f c = 3.4 wt%), the G–F/PDMS nanocomposites with 3.65 wt% of G–F nanosheets show a high conductivity, which is about 10 orders of magnitudes higher than that of pure PDMS, showing an obvious insulator–semiconductor transition. Moreover, the resistance of the nanocomposites with G–F filler near the percolation threshold exponentially increases with the uniaxial pressure. The normalized resistance ( R / R 0 ) can reach up to 870 at 0.88 MPa with 3.65 wt% G–F nanosheets loading. The G–F/PDMS nanocomposites also show superparamagnetism with saturation magnetization values of 0.21 emu g −1 . These results suggest that the G–F/PDMS nanocomposites in this work provide a new route to fabricate difunctional polymer-based nanocomposites with a potential application as flexible touch sensors.
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Analytical Methods
·
2015
·Vol. 7
·期 22
·9587-9595
·
IF 1.821
Shaojun Zhang,Wanqing Wu,Qinggong Zheng
In order to investigate the contamination caused by polycyclic aromatic hydrocarbons (PAHs) in seawater, Fe3O4 magnetic nanoparticle graphene (Fe3O4 MNG) was prepared and modified by micelles to act as an adsorbent for solid-phase microextraction. The method showed satisfactory precision, reproducibility and linear response (R2 > 0.9981) over the concentration range of 0.02–2.0 μg L−1. Limits of detection of 16 PAHs ranged from 0.009 to 0.018 μg L−1 (S/N = 3). The recovery of the established method (79.01–99.67%) was higher than that of the conventional solid-phase extraction method (29.27–88.04%). The enrichment factors of the PAHs were in the range of 53.85–103.64. The proposed method was successfully applied for the determination of PAHs in seawater samples collected from 56 different sites along the Bohai Sea in North China. The total concentrations of PAHs in seawater ranged between 54.90 and 8137.44 ng L−1.
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RSC Advances
·
2015
·Vol. 5
·期 117
·96911-96917
·
IF 3.84
Zhenliang Feng,Wenrui Wei,Litong Wang,Ruoyu Hong
Cross-linked PS-DVB/Fe3O4 microspheres (PFM-3) have been successfully synthesized by a new magnetic colloid swelling polymerization method and further functioned by alternatively using methylamine and 1,4-butanediol diglycidyl as monomers to build a branching polymer with quaternary ammonium groups. The characterization of PFM has been performed by XRD, FT-IR, SEM, TEM and BET surface area analyses. The results showed that PFM-3 possessed a high ion adsorption capacity (149.25 mg g−1) and could adsorb nitrate ions from water efficiently. The material also showed excellent reusability (after washing with sodium chloride, the absorption capacity was little reduced). More importantly, the magnetic microspheres could be removed from waste water easily via introducing an external magnetic field, which made the discoveries in this study provide an effective and environmentally friendly approach for fast removal of nitrate from waste water.
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MICROCHEMICAL JOURNAL
·
2015
·
IF 2.746
Zhirong Zou,Shanling Wang,Jia Jia,Fujian Xu,Zhou Long,Xiandeng Hou
In this work, magnetic Fe 3 O 4 @ZIF-8 core-shell nanoparticles (MNPs) were employed for effective adsorption of inorganic arsenic for preconcentration , with adsorption mechanism thoroughly discussed. The adsorbed inorganic arsenic was easily separated by a magnet along with the MNPs from the sample matrix, with possible matrix interference eliminated. The MNPs were then completely dissolved in hydrochloric acid prior to the determination of inorganic arsenic by hydride generation-atomic fluorescence spectrometry. The Fe 3 O 4 @ZIF-8 MNPs were prepared with a facile step-by-step assembly method in aqueous solution at room temperature . Under the optimized conditions, the sensitivity for inorganic arsenic determination was significantly increased through preconcentration, with satisfactory analytical merits obtained.
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JOURNAL OF SEPARATION SCIENCE
·
2013
·
IF 2.591
Xiaoji Cao,Jiaoyu Chen,Xuemin Ye,Feifei Zhang,Lingxiao Shen,Weimin Mo
An ultrasound-assisted magnetic SPE procedure with an Fe 3 O 4 -grafted graphene nanocomposite as the magnetic adsorbent has been developed to determine seven polychlorinated biphenyls (PCBs; PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, and PCB180) simultaneously in 200 mL environmental water samples, in combination with GC–MS/MS. Several factors related to magnetic SPE efficiencies, such as the superparamagnetic intensity and amount of adsorbent, extraction time, sample pH, and desorption conditions were investigated. With the assistance of ultrasound, the extraction achieved the maximum within only 20 s, attributed to the powerful adsorptive ability of the magnetic adsorbent toward the PCBs. Under the optimized conditions, an excellent linearity was observed in the range of 0.1–100 ng/L for PCB28, 0.2–100 ng/L for PCB52, and 0.5–100 ng/L for the other five PCBs with the correlation coefficients ranging from 0.9988 to 0.9996. The mean recoveries at spiked levels of 5.0 and 10.0 ng/L were 84.9–108.5%, the coefficients of variations were <6.5%. With convenient magnetic separation, the synthesized magnetic adsorbent could be recycled more than ten times. The proposed method was demonstrated to be feasible, simple, rapid, and easy to operate for the trace analysis of the PCBs in environmental water samples.
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高影响因子
DALTON TRANSACTIONS
·
2016
·Vol. 45
·期 13
·5484-5491
·
IF 4.177
Bo Li,Xudong Wang,Yali Guo,Anam Iqbal,Yaping Dong,Wu Li,Weisheng Liu,Wenwu Qin,Shizhen Chen,Xin Zhou,Yunhuang Yang
A one-step hydrothermal method was developed to fabricate Fe3O4–carbon dots (Fe3O4–CDs) magnetic–fluorescent hybrid nanoparticles (NPs). Ferric ammonium citrate (FAC) was used as a cheap and nontoxic iron precursor and as the carbon source. Moreover, triethylenetetramine (TETA) was used to improve the adhesive strength of CDs on Fe3O4 and the fluorescence intensity of CDs. The prepared water-soluble hybrid NPs not only exhibit excellent superparamagnetic properties (Ms = 56.8 emu g−1), but also demonstrate excitation-independent photoluminescence for down-conversion and up-conversion at 445 nm. Moreover, the prepared water-soluble Fe3O4–CDs hybrid NPs have a dual modal imaging ability for both magnetic resonance imaging (MRI) and fluorescence imaging.
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RSC Advances
·
2015
·Vol. 5
·期 130
·107670-107679
·
IF 3.84
Shoulian Wei,Jianwen Li,Yong Liu
Magnetic mesoporous nanoparticles of Fe3O4@mSiO2 were prepared through co-precipitation and tetraethoxysilane hydrolysis at 60 °C and pH 10 with hexadecyl trimethyl ammonium bromide as the template. Hydroxypropyl β-cyclodextrin was modified onto Fe3O4@mSiO2 under sodium citrate and N2 protection via an ultrasound process to increase the catalytic efficiency. The prepared nanoparticles were characterized by Fourier transform infrared spectrometry, X-ray diffraction, scanning electron microscopy and a peroxidase-like activity assay. The results showed that the prepared nanoparticles have magnetic properties, peroxidase-like activity and a loose spherical cluster structure. Compared with Fe3O4@mSiO2 nanoparticles, Fe3O4@mSiO2@HP-β-CD nanoparticles exhibit higher catalytic ability toward both H2O2 and 3,3′,5,5′-tetramethylbenzidine. Fe3O4@mSiO2@HP-β-CD nanoparticles can catalyse β-estradiol (β-E2) oxidation in the presence of H2O2 and be used as a colourimetric sensor for indirect detection of β-E2. A good linear relationship was obtained from 0.8 μM to 16 μM. The limit of detection of the proposed method was 0.2 μM. The visual method was successfully used in the analysis of β-E2 in commercial tablets and animal feeds, with recovery ranging from 92.6% to 110%.
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ChemCatChem
·
2017
·Vol. 9
·期 16
·3144-3152
·
IF 4.803
Yong Yuan,Shouying Huang,Hongyu Wang,Yifan Wang,Jian Wang,Jing Lv,Zhenhua Li,Xinbin Ma
Graphical Engineered catalysts : A monodisperse nano-Fe 3 O 4 on α-Al 2 O 3 catalyst synthesized by a novel two-step method of thermal decomposition and impregnation shows enhanced activity and stability for the Fischer–Tropsch synthesis to lower olefins. The effects of promoters (K and S) and size are investigated as well. The Fischer–Tropsch synthesis to lower olefins (FTO) is a desirable nonpetroleum-based route to produce basic chemicals. A novel two-step method was applied to synthesize iron-based supported catalysts, which is to prepare nano-Fe 3 O 4 first by thermal decomposition method and sequentially load them on α-Al 2 O 3 by impregnation. TEM and XRD results manifested that the controllable, uniform Fe 3 O 4 nanoparticles are monodispersed on the surface of α-Al 2 O 3 . H 2 -TPR demonstrated that the reduction of Fe species was facilitated because of the weak interaction between Fe species and the support. These superior properties contribute to an enhanced catalytic activity and stability compared with the catalyst prepared by directly impregnating ammonium iron citrate on α-Al 2 O 3 . Then, the effect of promoters was investigated at the same Fe loading and nanoparticle size. The appropriate addition of K could enhance the catalytic activity and suppress the secondary hydrogenation. On the contrary, S has a negative impact on CO conversion and strongly decreases C 5+ selectivity. Particularly, the combination of K and S could obtain more pronounced CO conversion and higher lower olefins selectivity (≈40 %). Furthermore, size effects were explored by precisely tailoring the iron oxide particle size with the Fe loading kept constant. It was found that 12.0 nm nano-Fe 3 O 4 on α-Al 2 O 3 with or without K plus S promoters showed the best catalytic activity among the catalysts with different particle size.
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