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1.
In the present study, we report new water-soluble cell fluorescence imaging and contrast agents that are based on DTPA-AMC(7-amino-4-methyl coumarin)-Eu(3+) and DTPA-AMC(7-amino-4-methyl coumarin)-Gd(3+) compounds conjugated to Fe(3)O(4) NPs via a PEG-NH(2) linker. The novel Fe(3)O(4) NP-conjugates present two main advantages for cell fluorescence labelling: water solubility and targeting ability. The in vitro experiments demonstrate that water-soluble Fe(3)O(4) NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Eu(3+) has excellent cell permeating activity. Moreover, the relaxation rate test of Fe(3)O(4) NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Gd(3+) shows a higher T1 relaxation effect than traditional DTPA-Gd(3+) MRI agents. According to in vivo liver MRI experiments, better contrast of the liver was achieved after addition of Fe(3)O(4) NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Gd(3+). The results will provide a significant guide for researchers exploring the biomedical applications of superparamagnetic Fe(3)O(4) NPs.  相似文献   

2.
Multiwalled boron nitride nanotubes (BNNTs) functionalized with Fe(3)O(4) nanoparticles (NPs) were used for arsenic removal from water solutions. Sonication followed by a heating process was developed to in situ functionalize Fe(3)O(4) NPs onto a tube surface. A batch of adsorption experiments conducted at neutral pH (6.9) and room temperature (25 °C) and using the developed nanocomposites revealed effective arsenic (V) removal. The Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms were measured for a range of As(V) initial concentrations from 1 to 40 mg/L under the same conditions. The equilibrium data well fitted all isotherms, indicating that the mechanism for As(V) adsorption was a combination of chemical complexation and physical electrostatic attraction with a slight preference for chemisorption. The magnetite NPs functionalized on BNNTs led to a simple and rapid separation of magnetic metal-loaded adsorbents from the treated water under an external magnetic field.  相似文献   

3.
In this work, we report the synthesis of magnetic sulfur-doped Fe3O4 nanoparticles (Fe3O4:S NPs) with a novel simple strategy, which includes low temperature multicomponent mixing and high temperature sintering. The prepared Fe3O4:S NPs exhibit a much better adsorption performance towards Pb(II) than bare Fe3O4 nanoparticles. FTIR, XPS, and XRD analyses suggested that the removal mechanisms of Pb(II) by Fe3O4:S NPs were associated with the process of precipitation (formation of PbS), hydrolysis, and surface adsorption. The kinetic studies showed that the adsorption data were described well by a pseudo second-order kinetic model, and the adsorption isotherms could be presented by Freundlich isotherm model. Moreover, the adsorption was not significantly affected by the coexisting ions, and the adsorbent could be easily separated from water by an external magnetic field after Pb(II) adsorption. Thus, Fe3O4:S NPs are supposed to be a good adsorbents for Pb(II) ions in environmental remediation.  相似文献   

4.
Porous Fe(3)O(4)@C nanocapsules with a diameter of about 120 nm (about 50 nm cavity) were synthesized by combining a sacrificial template method with solvothermal treatment. The N(2) adsorption-desorption isotherms reveals their mesoporous structure and large BET surface area (159.8 m(2) g(-1)). The magnetic investigation indicates their superparamagnetic nature and high saturation magnetization (55.93 emu g(-1)). The nanocapsules also exhibit negative zeta potential (-27.59 mV) and possess carboxyl groups on the outer carbon layer, which keeps them highly dispersive in aqueous solution and provides a chelating function for metal ions. The heavy metals removal test demonstrates the excellent affinity of nanocapsules, the high efficiency for different metals (>90%), 79 mg g(-1) adsorption capacity for Pb(2+) and ultrafast removal process (Pb(2+), 99.57% within 1 minute). Protected by a porous carbon layer, the nanocapsules display excellent acidic resistance and adsorption properties even in an acidic solution (pH = 3). Moreover, the metal ions can be easily adsorbed and desorbed through manipulating the pH value for adsorbent regeneration and heavy metal recycling.  相似文献   

5.
Mesoporous magnetic Fe3O4@C nanoparticles have been synthesized by a one-pot approach and used as adsorbents for removal of Cr (Ⅳ) from aqueous solution. Magnetic iron oxide nanostructured materials encapsulated by carbon were characterized by scanning electron microscope (SEM), nitrogen adsorption and desorption, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The adsorption performance of the nanomaterial adsorbents is tested with the removal of Cr (Ⅳ) from aqueous solution. The results reveal that the mesoporous magnetic Fe3O4@C nanospheres exhibit excellent adsorption efficiency and be easily isolated by an external magnetic field. In comparison with magnetic Fe3O4 nanospheres, the mesoporous magnetic Fe3O4@C exhibited 1.8 times higher removal rate of Cr Ⅵ. Themesoporous structure and an abundance of hydroxy groups on the carbon surfacemay be responsible for high absorbent capability.  相似文献   

6.
通过水溶液法将Fe3O4@SiO2负载到丙烯酸(AA)-丙烯酰胺(AM)-对苯乙烯磺酸钠(SSS)三元共聚水凝胶上,制备了具有高吸附能力的磁性水凝胶P(AA/AM/SSS)/Fe3O4@SiO2。通过傅里叶变换红外光谱,X射线衍射光谱,拉曼光谱和比表面孔径分析表征了磁性水凝胶的微观结构。该磁性水凝胶平均孔径3.1 nm,属于介孔材料,且具有较好的热稳定性。吸附性能研究发现其对重金属离子Pb2+,Cu2+,Co2+,Cd2+和Ni2+均显示出较高的去除率,其中对Pb2+表现出优异的选择性,最大吸附量为497 mg/g。吸附动力学研究表明,吸附过程遵循拟二级动力学模型。再生实验发现该水凝胶经过7次吸附-解吸循环后,磁性水凝胶饱和吸附容量仍保持在265 mg/g。  相似文献   

7.
Journal of Radioanalytical and Nuclear Chemistry - In this study, the UiO-66/Fe3O4/GO composite was prepared by one step method for removal of cesium ions (Cs+) in water and exhibited excellent...  相似文献   

8.
开发了一种磁性Fe3O4纳米粒子和2-(3,4-二羟苯基)苯并噻唑(DPB)修饰的磁性棒碳糊电极(MBCPE)用于电化学检测肼.首先将DPB自组装在Fe3O4纳米粒子上,然后将此复合物吸附于设计的MBCPE上. MBCPE电极将磁性纳米粒子吸引到电极表面.所得新型电极具有高的导电性和大的有效比表面积,因而对肼的电催化氧化反应有非常大的电流响应.采用伏安法、扫描电镜、电化学阻抗谱、红外光谱和紫外-可见光谱对修饰电极进行了表征.采用伏安法研究了在磷酸盐缓冲溶液(pH=7.0)中MBCPE/Fe3O4NPs/DPB电极上肼的电化学行为.作为电化学传感器, MBCPE/Fe3O4NPs/DPB电极对肼氧化反应表现出极高的电催化活性.在DPB存在下,肼的氧化电势下降,但其催化电流增加.电催化电流与肼浓度在0.1–0.4和0.7–12.0μmol/L二个区间内表现出线性关系,检测限为18.0 nmol/L.另外,研究了MBCPE/Fe3O4NPs/DPB电极同时检测肼和苯酚的性能.伏安实验结果显示,苯酚的线性区域为100–470μmol/L,检测限为24.3μmol/L.采用此电极检测了水样品中的肼和苯酚.  相似文献   

9.
Monodisperse chitosan-bound Fe(3)O(4) nanoparticles were developed as a novel magnetic nano-adsorbent for the removal of heavy metal ions. Chitosan was first carboxymethylated and then covalently bound on the surface of Fe(3)O(4) nanoparticles via carbodiimide activation. Transmission electron microscopy micrographs showed that the chitosan-bound Fe(3)O(4) nanoparticles were monodisperse and had a mean diameter of 13.5 nm. X-ray diffraction patterns indicated that the magnetic nanoparticles were pure Fe(3)O(4) with a spinel structure, and the binding of chitosan did not result in a phase change. The binding of chitosan was also demonstrated by the measurement of zeta potential, and the weight percentage of chitosan bound to Fe(3)O(4) nanoparticles was estimated to be about 4.92 wt%. The chitosan-bound Fe(3)O(4) nanoparticles were shown to be quite efficient for the removal of Cu(II) ions at pH>2. In particular, the adsorption rate was so fast that the equilibrium was achieved within 1 min due to the absence of internal diffusion resistance. The adsorption data obeyed the Langmuir equation with a maximum adsorption capacity of 21.5 mg g(-1) and a Langmuir adsorption equilibrium constant of 0.0165 L mg(-1). The pH and temperature effects revealed that the adsorption capacity increased significantly with increasing pH at pH 2-5, and the adsorption process was exothermic in nature with an enthalpy change of -6.14 kJ mol(-1) at 300-330 K.  相似文献   

10.
A low-cost adsorbent and environmentally friendly adsorbent from Carpobrotus edulis plant was used for the removal of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions from single, binary and multi-component systems. The efficiency of the adsorbent was studied using batch adsorption technique under different experimental conditions by varying parameters such as pH, initial concentration and contact time. In single component systems, the dried C. edulis has the highest affinity for Pb(2+), followed by NO(3)(-), Cd(2+) and H(2)PO(4)(-), with adsorption capacities of 175mg/g, 125mg/g, 28mg/g and 26mg/g, respectively. These results showed that the adsorption of NO(3)(-) and H(2)PO(4)(-) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. Freundlich adsorption model, showed the best fit to the single and binary experimental adsorption data. These results also indicated that the adsorption yield of Pb(2+) ion was reduced by the presence of Cd(2+) ion in binary metal mixture. The competitive adsorption of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions on dried C. edulis plant shows that NO(3)(-) and H(2)PO(4)(-) anions are able to adsorb on different free binding sites and Pb(2+) and Cd(2+) cations are able to adsorb on the same active sites of C. edulis particles. The dried C. edulis was found to be efficient in removing nitrate, phosphate, cadmium and lead from aqueous solution as compared to other adsorbents already used for the removal of these ions.  相似文献   

11.
In this paper, we report the preparation of γ-Fe(2)O(3) and Fe(3)O(4) magnetic hierarchically nanostructured hollow microspheres by a solvothermal combined with precursor thermal conversion method. These γ-Fe(2)O(3) and Fe(3)O(4) magnetic hierarchically nanostructured hollow microspheres were constructed by three-dimensional self-assembly of nanosheets, forming porous nanostructures. The effects of experimental parameters including molar ratio of reactants and reaction temperature on the precursors were studied. The time-dependent experiments indicated that the Ostwald ripening was responsible for the formation of the hierarchically nanostructured hollow microspheres of the precursors. γ-Fe(2)O(3) and Fe(3)O(4) magnetic hierarchically nanostructured hollow microspheres were obtained by the thermal transformation of the precursor hollow microspheres. Both γ-Fe(2)O(3) and Fe(3)O(4) hierarchically nanostructured hollow microspheres exhibited a superparamagnetic property at room temperature and had the saturation magnetization of 44.2 and 55.4emu/g, respectively, in the applied magnetic field of 20 KOe. Several kinds of organic pollutants including salicylic acid (SA), methylene blue (MB), and basic fuchsin (BF) were chosen as the model water pollutants to evaluate the removal abilities of γ-Fe(2)O(3) and Fe(3)O(4) magnetic hierarchically nanostructured hollow microspheres. It was found that γ-Fe(2)O(3) hierarchically nanostructured hollow microspheres showed a better adsorption ability over SA than MB and BF. However, Fe(3)O(4) hierarchically nanostructured hollow microspheres had the best performance for adsorbing MB.  相似文献   

12.
Wu SP  Chen YP  Sung YM 《The Analyst》2011,136(9):1887-1891
A sensitive, selective colorimetric Fe(3+) detection method has been developed by using pyrophosphate functionalized gold nanoparticles (P(2)O(7)(4-)-AuNPs). Gold nanoparticles were prepared by reducing HAuCl(4) with sodium borohydride, in the presence of Na(4)P(2)O(7). IR spectra suggested that pyrophosphates were capped on the surface of the gold nanoparticles. Aggregation of P(2)O(7)(4-)-AuNPs was induced immediately in the presence of Fe(3+) ions, yielding a color change from pink to violet. This Fe(3+)-induced aggregation of P(2)O(7)(4-)-AuNPs was monitored using first the naked eye and then UV-vis spectroscopy with a detection limit of 5.6 μM. The P(2)O(7)(4-)-AuNPs bound by Fe(3+) showed excellent selectivity compared to other metal ions (Ca(2+), Cd(2+), Co(2+), Fe(2+), Hg(2+), K(+), Mg(2+), Mn(2+), Na(+), Ni(2+), Pb(2+), and Zn(2+)). The best detection of Fe(3+) was achieved in a pH range from 3 to 9. In addition, the P(2)O(7)(4-)-AuNPs were also used to detect Fe(3+) in lake water samples, with low interference.  相似文献   

13.
A novel type of superparamagnetic silica-coated (Fe3O4/SiO2 core/shell) magnetite nanoparticle modified by surfactants has been successfully synthesized and was applied as an effective sorbent material for the pre-concentration of several typical phenolic compounds (bisphenol A (BPA), 4-tert-octylphenol (4-OP) and 4-n-nonylphenol (4-NP)) from environmental water samples. Compared with pure magnetic particles, a thin and dense silica layer would protect the iron oxide core from leaching out in acidic conditions. In order to enhance their adsorptive tendency towards organic compounds, cetylpyridinium chloride (CPC) or cetyltrimethylammonium bromide (CTAB) were added, which adsorbed on the surface of the Fe3O4/SiO2 nanoparticles (Fe3O4/SiO2 NPs) and formed mixed hemimicelles. Main factors affecting the adsolubilization of analytes were optimized and comparative study on the use of CPC and CTAB-coated Fe3O4/SiO2 NPs mixed hemimicelles-based SPE was also carried out. CPC-coated Fe3O4/SiO2 NPs system was selected due to lower elution volume required and more effective adsorption of the target compounds. Under selected conditions, concentration factor of 1600 was achieved by using this method to extract 800 mL of different environmental water samples. The detection limits obtained for BPA, 4-OP and 4-NP with HPLC-FLD were 7, 14, and 20 ng/L, respectively.  相似文献   

14.
Lee YF  Deng TW  Chiu WJ  Wei TY  Roy P  Huang CC 《The Analyst》2012,137(8):1800-1806
We have developed a simple, low-cost, paper-based probe for the selective colorimetric detection of copper ions (Cu(2+)) in aqueous solutions. The bovine serum albumin (BSA)-modified 13.3-nm Au nanoparticle (BSA-Au NP) probe was designed to detect Cu(2+) ions using lead ions (Pb(2+)) and 2-mercaptoethanol (2-ME) as leaching agents in a glycine-NaOH (pH 12.0) solution. In addition, a nitrocellulose membrane (NCM) was used to trap the BSA-Au NPs, leading to the preparation of a nanocomposite film consisting of a BSA-Au NP-decorated membrane (BSA-Au NPs/NCM). The BSA-Au NPs probe operates on the principle that Cu deposition on the surface of the BSA-Au NPs inhibits their leaching ability, which is accelerated by Pb(2+) ions in the presence of 2-ME. Under optimal solution conditions (5 mM glycine-NaOH (pH 12.0), Pb(2+) (50 μM), and 2-ME (1.0 M)), the Pb(2+)/2-ME-BSA-Au NPs/NCM enabled the detection of Cu(2+) at nanomolar concentrations in aqueous solutions by the naked eye with high selectivity (at least 100-fold over other metal ions). In addition, this cost-effective probe allowed for the rapid and simple determination of Cu(2+) ions in not only natural water samples but also in a complex biological sample (in this case, blood sample).  相似文献   

15.
Porous spinel ferrites Mn(1-x)Zn(x)Fe(2)O(4) (0 ≤ x ≤ 0.8) are synthesized by a simple sol-gel method with egg white. All samples exhibit porous morphologies and large BET surface area (S(BET)). The substitution of Zn(2+) affects the magnetic properties of ferrites and the adsorption properties of methylene blue (MB) on ferrites, obviously. The saturation magnetization (Ms) of Mn(1-x)Zn(x)Fe(2)O(4) increases before x=0.4, and decreases with further increase of Zn(2+) substitution. This can be ascribed to the changes of the cationic distribution and the variation of spin arrangement in A-site and B-site of spinel structure. All samples show high adsorption capacity and the removal efficiencies of MB reach up to >90% within 3 h. The Zn(2+) substitution accelerates the adsorption rate and capacity of MB on Mn(1-x)Zn(x)Fe(2)O(4). The quickest adsorption occurred at x=0.2 and the largest adsorption capacity occurred at x=0.8.  相似文献   

16.
Mixed hemimicelles solid-phase extraction (SPE) based on cetyltrimethylammonium bromide (CTAB)-coated nano-magnets Fe3O4 was investigated for the preconcentration of four chlorophenols (CPs) in environmental water samples prior to HPLC-spectrophotometry determination in this paper. By the rapid isolating (about 5 min) of Fe3O4 nanoparticles (NPs) through placing a Nd-Fe-B strong magnet on the bottom of beaker, the time-consuming preconcentration process of loading large volume sample in conversional SPE method with a column can be avoided. The unique properties of Fe3O4 NPs such as high surface area and strong magnetism were utilized adequately in the SPE process. This novel separation method produced a high preconcentration rate and factor. A comprehensive study of the adsorption conditions such as the Fe3O4 NPs zeta-potential, CTAB added amounts, pH value, standing time and maximal extraction volume was also presented. Under optimized conditions, four analytes of 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (TCP) and pentachlorophenol (PCP) were quantitatively extracted. The method was then used to determine four CPs in five real environmental water samples. High concentration factors (700) were achieved for each of the analytes, with observed detection limits ranging between 0.11 and 0.15 microg L(-1). The accuracy of method was evaluated by recovery measurements on spiked samples. Good recovery results (83-98%) with satisfactory relative standard deviation (RSD) were achieved. It is important to note that satisfactory preconcentration factors and extraction recoveries for the four CPs were obtained with only a little amount of Fe3O4 NPs (0.1g) and CTAB (60 mg). To the best of our knowledge, this was the first time a mixed hemimicelles SPE method based on Fe3O4 NPs magnetic separation had been used for the pretreatment of environmental water samples.  相似文献   

17.
Magnetic manganese oxide nanostructures are fabricated at room temperature by mixing a KMnO(4) solution and oleic acid capped Fe(3)O(4) particles. Oleic acid molecules capped Fe(3)O(4) particles are oxidized by potassium permanganate (KMnO(4)) in an aqueous solution to produce porous magnetic manganese oxide nanostructures. The synthesis technique can be extended to other MnO(x) structures with composition of different nanocrystals, such as quantum dots, noble metal crystals which may have important applications as catalysts, adsorbents, electrodes and advanced materials in many scientific disciplines. Transmission electron microscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and nitrogen adsorption-desorption measurements are employed to characterize the structures. As an adsorbent in water treatment, the nanostructures possess a large adsorption capability and high organic pollutant removal rates due to the large surface area and pore volume. The nanostructures are recyclable as their adsorption capability can be recovered by combustion. Furthermore, the strong magnetism exhibited by the structures provides an easy and efficient separation means in wastewater treatment under an external magnetic field.  相似文献   

18.
Hybrid materials formed by the combination of a sodium rich Montmorillonite (MMT), with magnetite nanoparticles (40nm, Fe(3)O(4) NPs) coated with Polyethylenimine polymer (PEI 800g/mol or PEI 25000g/mol) were prepared. The intercalation of the magnetite nanoparticles coated with PEI among MMT platelets was achieved by cationic exchange. The resulting materials presented a high degree of exfoliation of the MMT sheets and a good dispersion of Fe(3)O(4) NPs on both the surface and among the layers of MMT. The presence of amine groups in the PEI structure not only aids the exfoliation of the MMT layers, but also gives to the hybrid material the necessary functionality to interact with heavy metals. These hybrid materials were used as magnetic sorbent for the removal of hexavalent chromium from water. The effect that pH, Cr(VI) concentration, and adsorbent material composition have on the Cr(VI) removal efficiency was studied. A complete characterization of the materials was performed. The hybrid materials showed a slight dependence of the removal efficiency with the pH in a wide range (1-9). A maximum amount of adsorption capacity of 8.8mg/g was determined by the Langmuir isotherm. Results show that these hybrid materials can be considered as potential magnetic adsorbent for the Cr(VI) removal from water in a wide range of pH.  相似文献   

19.
A chelating resin based on modified poly (styrene‐alt‐maleic anhydride) with 3‐aminobenzoic acid was synthesized. This modified resin was further reacted by 1,2‐diaminoethane or 1,3‐diaminopropane in the presence of ultrasonic irradiation to prepare tridimensional chelating resin for the removal of heavy metal ions from aqueous solutions. The adsorption behavior of Fe(II), Cu(II), Zn(II) and Pb(II) ions was investigated by synthesized chelating resins in various pH. Among the synthesized resins, CSMA‐AB1 and CSMA‐AB2 demonstrated a high affinity for the selected metal ions compared to SMA‐AB, and the order of removal percentage changes as follow: Fe(II) > Cu(II) > Zn(II) > Pb(II). The adsorption of all metal ions in acidic medium was moderate, and it was favored at the pH value of 6 and 7. Also, the prepared resins were examined for removal of metal ions from industrial wastewater and were shown to have a very efficient adsorption in the case of Cu(II), Fe(II) and Pb(II); however, the adsorption of Zn(II) was lower than others. The resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction analysis and thermogravimetric analysis/derivative thermogravimetry. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

20.
LIANG  Xuefeng  HOU  Wanguo  XU  Jie 《中国化学》2009,27(10):1981-1988
Mg‐Fe layered double hydroxide (LDH) with a Mg/Fe molar ratio of 3:1 was synthesized by using a coprecipitation method and the sorption removal of Pb(II) by the LDH sample from Pb(NO3)2 solution was investigated. It was found that Mg‐Fe LDH showed a good sorption ability for Pb(II) from Pb(NO3)2 solution, indicating that the use of LDH as a promising inorganic sorbent for the removal of heavy metal ions is possible. The sorption kinetics and the sorption isotherm of Pb(II) on the LDH sample obeyed the pseudo‐second order kinetic model and Aranovich‐Donohue equation, respectively. The sorption mechanism of Pb(II) on the LDH may be attributed to the surface‐induced precipitation and the chemical binding adsorption, and the removal ability arising from the surface‐induced precipitation is much higher than that from the chemical binding adsorption.  相似文献   

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