Bi2Fe4O9纳米粉体:水热法制备及表征

Bi₂Fe₄O₉ nanoparticles were prepared at low temperature via a facile, one-step hydrothermal synthesis process using iron(Ⅲ) nitrate nonahydrate(Fe(NO₃)₃·9H₂O) and bismuth nitrate pentahydrate (Bi(NO₃)₃·5H₂O) as starting materials and sodium hydroxide (NaOH) as the precipitant and mineralizer. XRD results indicate that the as-prepared nanoparticles are pure Bi₂Fe₄O₉. SEM images reveal that the as-prepared Bi₂Fe₄O₉ nanoparticles have a sheet-like morphology. The Bi₂Fe₄O₉ nanoparticles thus obtained are paramagnetic at room temperature as shown by magnetic measurements.     

纳米Fe3O4及Ni2+掺杂Fe3O4的制备、表征及吸附Pb(Ⅱ)的特性

采用一种改进的共沉淀法制备了纳米磁铁矿(Fe₃O₄)及Ni²⁺掺杂磁铁矿(Ni_xFe_3-xO₄,x=0.1,0.3,0.6),用X-射线衍射(XRD)、扫描电镜(SEM)、氮气物理性吸附、酸碱滴定等手段对产物进行了表征,用平衡吸附法研究了4种样品对Pb(Ⅱ)离子的吸附容量及吸附模型。结果表明,Fe₃O₄和3种Ni_xFe_3-xO₄均为近似球形的单相晶质纳米颗粒;与Fe₃O₄比较,Ni_xFe_3-xO₄的颗粒尺寸变小、表面电荷零点和pH＝5.0时的表面正电荷量降低;样品的孔体积、比表面积和表面分形度以及表面羟基含量都随产物中Ni²⁺掺杂量的增加而升高。4种样品对Pb(Ⅱ)的等温吸附数据均适合用Langmuir模型拟合(R₂=0.9942~0.9858),其相关系数的大小表现为:Fe₃O₄>Ni_0.1Fe_2.9O₄>Ni_0.3Fe_2.7O₄=Ni_0.6Fe_2.4O₄;Freundlich模型对样品等温吸附Pb(Ⅱ)的实验数据拟合度较低(R²=0.9813~0.9477),4种样品的Freundlich相关系数的大小关系与Langmuir相关系数相反。初始pH=5.0时,Fe₃O₄,Ni_0.1Fe_2.9O₄,Ni_0.3Fe_2.7O₄和Ni_0.6Fe_2.4O₄对Pb(Ⅱ)的最大吸附容量分别为6.02,6.68,7.29和8.34mg·g^-1。可见,Ni_xFe_3-xO₄(尤其是Ni²⁺掺杂量较高的产物)对水环境中重金属Pb(Ⅱ)的去除能力明显高于Fe₃O₄。     

Fe3O4磁性纳米粒子的超声包金及其表征

超声条件下, 在乙醇分散的3-氨丙基三乙氧基硅烷(APTES)功能化的磁性Fe₃O₄纳米粒子和四氯合金酸的混合溶液中滴加柠檬酸钠, 成功地制备了磁性Fe₃O₄/Au复合纳米粒子. 采用X射线粉末衍射仪(XRD)、紫外吸收可见光谱(UV-Vis)、带有电子能谱仪(EDS)的扫描电子显微镜(SEM)、透射电子显微镜(TEM)、光电子能谱(XPS)、超导量子干涉仪(SQUID)等方法, 对复合粒子的形态、结构、组成以及磁学性质进行了表征. 结果表明: 在此条件下制得的复合粒子粒径在30 nm左右, 室温下磁化强度可达63 emu/g.     

不同形貌Fe3O4纳米粒子的氧化沉淀法制备与表征

用一种方法成功合成出了球体、四方体、八面体、不规则多面体、三角形和不规则颗粒等六种具有不同形貌的Fe₃O₄纳米粒子，通过扫描电子显微镜(SEM)表征了粒子形貌。试样经过X-射线衍射(XRD)表征具有尖晶石结构，且结晶良好。经震动样品磁强计(VSM)测定，各种形貌的Fe₃O₄纳米粒子都具有良好的磁性，其中八面体形貌的Fe₃O₄纳米粒子的饱和磁化强度达到86.56 emu·g^-1，剩磁为10.64 emu·g^-1，矫顽力为138 Oe。讨论了不同形貌的Fe₃O₄纳米粒子的形成机制，得出了晶核的生长环境对纳米粒子的形貌有重要影响的结论。     

纳米Fe3O4及Ni2 掺杂Fe3O4的制备、表征及吸附Pb(Ⅱ)的特性

采用一种改进的共沉淀法制备了纳米磁铁矿(Fe₃O₄)及Ni²⁺掺杂磁铁矿(Ni_xFe_3-xO₄,x=0.1,0.3,0.6),用X-射线衍射(XRD)、扫描电镜(SEM)、氮气物理性吸附、酸碱滴定等手段对产物进行了表征,用平衡吸附法研究了4种样品对Pb(Ⅱ)离子的吸附容量及吸附模型。结果表明,Fe₃O₄和3种Ni_xFe_3-xO₄均为近似球形的单相晶质纳米颗粒;与Fe₃O₄比较,Ni_xFe_3-xO₄的颗粒尺寸变小、表面电荷零点和pH＝5.0时的表面正电荷量降低;样品的孔体积、比表面积和表面分形度以及表面羟基含量都随产物中Ni²⁺掺杂量的增加而升高。4种样品对Pb(Ⅱ)的等温吸附数据均适合用Langmuir模型拟合(R²=0.9942~0.9858),其相关系数的大小表现为：Fe₃O₄>Ni_0.1Fe_2.9O₄>Ni_0.3Fe_2.7O₄=Ni_0.6Fe_2.4O₄;Freundlich模型对样品等温吸附Pb(Ⅱ)的实验数据拟合度较低(R²=0.981 3~0.947 7),4种样品的Freundlich相关系数的大小关系与Langmuir相关系数相反。初始pH=5.0时,Fe₃O₄,Ni_0.1Fe_2.9O₄,Ni_0.3Fe_2.7O₄和Ni_0.6Fe_2.4O₄对Pb(Ⅱ)的最大吸附容量分别为6.02,6.68,7.29和8.34 mg·g^-1。可见,Ni_xFe_3-xO₄(尤其是Ni²⁺掺杂量较高的产物)对水环境中重金属Pb(Ⅱ)的去除能力明显高于Fe₃O₄。     

用于高效去除水中孔雀石绿的三层结构磁性复合材料Fe3O4@聚丙烯酸@ZiF-8的制备

设计并合成了一种以磁性纳米粒子为核，聚合物为中间层，金属有机骨架材料为外层的三层结构磁性复合材料(Fe₃O₄@PAA@ZIF 8)。首先利用溶剂热法制备Fe₃O₄纳米粒子，然后通过蒸馏沉淀聚合法在Fe₃O₄纳米粒子表面包覆聚丙烯酸(PAA)层，最后通过原位沉积法在PAA外部包覆ZIF 8。在对Fe₃O₄@PAA@ZIF 8的组成和结构进行表征的基础上，深入研究其对孔雀石绿(MG)的吸附性能。透射电子显微镜(TEM)显示 Fe₃O₄@PAA@ZIF 8 具有明显的三层结构，Fe₃O₄的平均粒径为 117nm，PAA 层厚度约为 17 nm，ZIF 8层的厚度约为 14 nm。Fe₃O₄@PAA@ZIF 8对 MG 的吸附量随着 pH 的升高而增大，吸附过程符合准二阶动力学模型和 Langmuir等温吸附模型。此外，Fe₃O₄@PAA@ZIF 8还表现出良好的重复利用性能，8次循环利用后对MG(500 mg·L^-1)的最大吸附量仍可达982 mg·g^-1。     

水溶性纳米Fe3O4-阿魏酸抗凝血材料的合成及性能

为提高具抗凝血性能的阿魏酸分子在水中的溶解性进而提高其药效,利用DBI(3,4-二羟基苯甲醛)、PEG(聚乙二醇4000)和纳米Fe₃O₄,采用接枝的方法制备了水溶性纳米Fe₃O₄-DBI-PEG-阿魏酸抗凝血杂化材料,用IR、¹H NMR、TG、SEM、TEM、VSM和粒度测试方法表征了产物。结果表明阿魏酸(FA)接枝在了经过DBI-PEG活化后的纳米Fe₃O₄氧化物表面。杂化材料具有良好的水溶性(溶解度大于10 mg·mL^-1)和顺磁性。抗凝血试验表明相同条件下杂化材料的抗凝血时间和复钙时间比阿魏酸要长,杂化材料的活化部分凝血活酶时间(APTT)和凝血酶原时间(PT)比空白组要长,杂化材料的抗凝血时间随浓度的增大而延长。     

水溶性纳米Fe3O4-阿魏酸抗凝血材料的合成及性能

为提高具抗凝血性能的阿魏酸分子在水中的溶解性进而提高其药效,利用DBI(3,4-二羟基苯甲醛)、PEG(聚乙二醇4000)和纳米Fe₃O₄,采用接枝的方法制备了水溶性纳米Fe₃O₄-DBI-PEG-阿魏酸抗凝血杂化材料,用IR、¹H NMR、TG、SEM、TEM、VSM和粒度测试方法表征了产物。结果表明阿魏酸(FA)接枝在了经过DBI-PEG活化后的纳米Fe₃O₄氧化物表面。杂化材料具有良好的水溶性(溶解度大于10 mg·mL^-1)和顺磁性。抗凝血试验表明相同条件下杂化材料的抗凝血时间和复钙时间比阿魏酸要长,杂化材料的活化部分凝血活酶时间(APTT)和凝血酶原时间(PT)比空白组要长,杂化材料的抗凝血时间随浓度的增大而延长。     

球形纳米Fe3O4的制备及超级电容性能研究

采用双氧水氧化水热法制备Fe₃O₄,通过IR、XRD和SEM对样品的结构和性能进行表征。结果表明,产物为形貌规整的球形,平均粒径为25 nm。通过恒流充放电、循环伏安和交流阻抗等方法研究Fe₃O₄电极的电容性能。电化学测试表明,在1 mol·L^-1 Na₂SO₃溶液中,-1.2～0.2 V(vs SCE)电位范围内,Fe₃O相似文献   

磁性Fe3O4 /壳聚糖的化学修饰及包覆机理研究

Nano-sized Fe₃O₄ powder was prepared through an Oxygenation-Hydrothermal method. The chitosan magnetic complex was prepared by coating chitosan on the surface of Fe₃O₄ powders through Microlatex-Crosslinking Method. The product was characterized by IR， XRD， TEM， Vibrating Sample Magnetometer (VSM)， TG methods. Results show that the as-prepared powder is 25 nm in size and shows supermagnetism. The content of magnetite in microspheres is 37.8%. The mechanism for the coating reaction of chitosan to Fe₃O₄ nanoparticles is also suggested.     

Microwave-assisted synthesis and characterization of hexagonal Fe3O4 nanoplates

Hexagonal magnetite (Fe₃O₄) nanoplates with an average edge length of 80 nm were successfully prepared in large quantities by a facile microwave-assisted route. The influences of experiment parameters such as reaction time, microwave power, and concentration of NaOH and other additive agents on the morphology and size of final products were investigated in detail. Phase structure, morphology and magnetic properties of products were carefully studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), high-resolution transmission electron microscope (HRTEM), and vibrating sample magnetometer (VSM). Magnetic studies revealed that hexagonal Fe₃O₄ nanoplates have low saturation magnetization of 36.4 emu/g and the possible reason has been proposed.     

High-yield synthesis and characterization of monodisperse sub-microsized CoFe2O4 octahedra

In this study, sub-microsized CoFe₂O₄ octahedra with a high yield are synthesized via a simple hydrothermal route under mild conditions. The as-prepared products are characterized by conventional techniques of XRD, SEM, TEM, ED and HR-TEM. The results show that the as-synthesized sample exhibits octahedral morphology with a narrow size distribution. The edge size of CoFe₂O₄ octahedra is estimated to be about 0.10-0.14 μm. The growth process is also monitored by time and temperature-dependent observation. It is found that the reaction temperature has no obvious influence on the product morphology but a significant effect on the size of CoFe₂O₄ octahedra, while the reaction time determines the final morphology of the product. Moreover, it is displayed that the citrate ions play a key role in the formation of CoFe₂O₄ octahedra. Furthermore, the possible growth mechanism of the sub-microsized CoFe₂O₄ octahedra is discussed on the basis of a series of experiments. Magnetic measurements show that sub-micro-sized CoFe₂O₄ octahedra exhibit obvious ferromagnetic behaviors. The saturation magnetization (M_s), remanent magnetization (M_r), and coercivity (H_c) are determined to be 85.8, 29.2 emu/g and 892 Oe, respectively.     

Template free solvothermal synthesis of single crystal magnetic Fe3O4 hollow spheres,their interaction with bovine serum albumin and antibacterial activities

Uniform sized single crystal magnetic Fe₃O₄ hollow spheres (MFHS) have been synthesized through simple solvothermal method using ferric chloride hexahydrate and 1,3-propanediamine. The reaction time and the amount of 1,3-propanediamine play major roles in the formation of magnetic Fe₃O₄ hollow spheres. The synthesized products are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometry techniques. The crystalline Fe₃O₄ materials are composed of well-aligned hollow sphere magnetite nanoparticles and exhibit high saturation magnetization of 57.9?emu/g and a remnant magnetization of 17.6?emu/g at room temperature. MFHS interact strongly with bovine serum albumin (BSA) and brings out considerable conformational changes in BSA as evident from the UV–vis absorption, fluorescence and circular dichroism (CD) spectroscopic studies pertaining to the interaction of synthesized MFHS and BSA. The prepared MFHS effectively inhibit the growth of Pseudomonas aeruginosa and Staphylococcus aureus.     

Self-assembly of Fe3O4 nanocrystal-clusters into cauliflower-like architectures: Synthesis and characterization

Large-scale cauliflower-like Fe₃O₄ architectures consist of well-assembled magnetite nanocrystal clusters have been synthesized by a simple solvothermal process. The as-synthesized Fe₃O₄ samples were characterized by XRD, XPS, FT-IR, SEM, TEM, etc. The results show that the samples exhibit cauliflower-like hierarchical microstructures. The influences of synthesis parameters on the morphology of the samples were experimentally investigated. Magnetic properties of the Fe₃O₄ cauliflower-like hierarchical microstructures have been detected by VSM at room temperature, showing a relatively low saturation magnetization of 65 emu/g and an enhanced coercive force of 247 Oe.     

Synthesis and characterization of novel magnetic Fe3O4/polyphosphazene nanofibers

Novel magnetic Fe₃O₄/polyphosphazene nanofibers were successfully prepared via a facile approach by ultrasonic irradiation. The structure and morphology were characterized by SEM, TEM, EDX, IR and XRD. The characterization results show that the magnetic Fe₃O₄/polyphosphazene nanofibers are several microns in length and 50–100 nm in diameter with Fe₃O₄ nanoparticles of 5–10 nm attached on the surface. The interaction between Fe₃O₄ nanoparticles and polyphosphazene nanofibers was thought as coordination behavior. TG curves show that the magnetic Fe₃O₄/polyphosphazene nanofibers have good thermostability and high magnetism content of about 44%. Magnetic studies show that the magnetic nanofibers exhibit good superparamagnetic properties with high magnetization saturation value of about 36 emu/g.     

Synthesis and properties of magnetite Fe3O4 via a simple hydrothermal route

Magnetic Fe₃O₄ crystals were synthesized by a simple hydrothermal method using K₄Fe(CN)₆ as single precursor. The chemical compositions and morphologies of the as-prepared samples were characterized in detail by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and scanning electron microscopy (SEM). The experimental results show that the magnetic Fe₃O₄ particles are facilely prepared by the hydrothermal reaction of K₄Fe(CN)₆ and NaOH at 200 °C. Regular octahedral Fe₃O₄ crystals are obtained when Na₂S₂O₃ is added to the reaction system. The possible mechanism was discussed to elucidate the formation of the magnetic Fe₃O₄ crystals. Besides, the magnetic investigations show that the values of saturation magnetization and coercivity of octahedral Fe₃O₄ are about 87 emu/g and 184 Oe, respectively. Octahedral Fe₃O₄ also exhibits relatively good catalytic performance in the oxidation of styrene.     

Synthesis of superparamagnetic and thermoresponsive hybrid nanoparticles via surface‐mediated RAFT polymerization of di(ethylene glycol) ethyl ether acrylate and (oligoethylene glycol) methyl ether acrylate

A reversible addition‐fragmentation chain transfer (RAFT) agent was directly anchored onto superparamagnetic Fe₃O₄ nanoparticles (SPNPs) in a simple procedure using a ligand exchange reaction of 2‐[(dodecylsulfanylcarbonylthiolsulfanyl) propionic acid] (DCPA) with oleic acid initially present on the surface of Fe₃O₄ nanoparticles. The DCPA‐modified SPNPs were then used for the surface‐mediated RAFT polymerization of di(ethylene glycol) ethyl ether acrylate and (oligoethylene glycol) methyl ether acrylate to fabricate structurally well‐defined hybrid SPNPs with temperature‐responsive poly[di(ethylene glycol) ethyl ether acrylate‐co‐(oligoethylene glycol) methyl ether acrylate] shell and magnetic Fe₃O₄ core. Evidence of a well‐controlled surface‐mediated RAFT polymerization was gained from a linear increase of number‐average molecular weight with overall monomer conversions and relatively narrow polydispersity indices of the copolymers grown from the SPNPs. The resultant hybrid nanoparticles exhibited superparamagnetic property with a saturation magnetization of 55.1–19.4 emu/g and showed a temperature‐responsive phenomenon as the temperature changed between 25 and 40 ^°C. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3420–3428     

单分散Fe3O4纳米颗粒的控制合成和表征

以十八烯为溶剂、乙酰丙酮铁为铁源,并在油酸、油胺的辅助作用下,通过热分解法成功合成了单分散Fe3O4纳米颗粒。讨论了实验参数如反应温度、表面活性剂的量和种类、溶剂、油酸、油胺对单分散Fe3O4纳米颗粒的尺寸及形貌的影响。利用X射线衍射（XRD）、透射电子显微镜（TEM）、选区电子衍射（SAED）和高分辨透射电子显微镜（HRTEM）对所得产物的物相、结构、尺寸和形貌进行了表征分析。通过振动样品磁强计（VSM）表征产物磁性能,表明在室温下,Fe3O4纳米颗粒的饱和磁化强度（Ms）和矫顽力（Hc）分别为74.0 emu/g,72.6 Oe。     

Magnetic and Thermal Properties of Novel Poly(ether-amide)/Fe3O4 Nanocomposite Containing Phosphine Oxide Group

New poly(ether-amide) nanocomposite containing phosphine oxide was prepared via solution polymerization process from synthesized poly(ether-amide) and Fe₃O₄ nanoparticles in a solution of N,N-dimethylformamide. Uniform monodisperse Fe₃O₄ nanoparticles were synthesized at room temperature via a facile sonochemical reaction. Poly(ether-amide) (PEA) as the polymer matrix was synthesized from reaction of 1,4-(4-carboxy phenoxy)butane (1) and bis(3-amino phenyl)phenyl phosphine oxide (2) via a direct polycondensation reaction. Nanoparticle and nanocomposite were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared. The effect of the presence of Fe₃O₄ nanoparticles on the thermal properties of PEA was studied using thermogravimetric analysis in nitrogen atmospheres. The magnetic properties of the sample were also investigated using an alternating gradient force magnetometer. We found that the Fe₃O₄ nanoparticles exhibit a ferromagnetic behaviour with a saturation magnetization of 59 emu/g and a coercivity of 104 Oe at room temperature. The coercivity of PEA/Fe₃O₄ nanocomposites is found to be 126 Oe, higher than 104 Oe which is obtained for Fe₃O₄.     

Preparation of MnxNi0.5-xZn0.5Fe2O4 Nanorods by the Co-precipitation Method

Mn_xNi_0:5-xZn_0:5Fe₂O₄ nanorods were successfully synthesized by the thermal treatment of rod-like precursors that were fabricated by the co-precipitation of Mn²⁺, Ni²⁺, and Fe²⁺ in the lye. The phase, morphology, and particle diameter were examined by the X-ray diffrac-tion and transmission electron microscopy. The magnetic properties of the samples were stud-ied using a vibrating sample magnetometer. The results indicated that pure Ni_0:5Zn_0:5Fe₂O₄ nanorods with a diameter of 35 nm and an aspect ratio of 15 were prepared. It was found that the diameter of the Mn_xNi_0:5-xZn_0:5Fe₂O₄ (0≤x≤0.5) samples increased, the length and the aspect ratio decreased, with an increase in x value. When x=0.5, the diameter and the aspect ratio of the sample reached up to 50 nm and 7～8, respectively. The coercivity of the samples first increased and then decreased with the increase in the x value. The coer-civity of the samples again increased when the x value was higher than 0.4. When x=0.5,the coercivity of the Mn_xNi_0:5-xZn_0:5Fe₂O₄ sample reached the maximal value (134.3 Oe)at the calcination temperature of 600 oC. The saturation magnetization of the samples first increased and then decreased with the increase in the x value. When x=0.2, the satura-tion magnetization of the sample reached the maximal value (68.5 emu/g) at the calcination temperature of 800 oC.