超顺磁性纳米Fe_3O_4的制备、表面改性方法与应用研究

对超顺磁性Fe3O4纳米粒子的制备方法及表面改性方法进行了总结,目前常用的方法有微乳液法、水热法、共沉淀法、溶胶-凝胶法及水解法,讨论了这些方法的优缺点,并对超顺磁性Fe3O4纳米粒子的应用作简单的介绍,对其进一步的研究进行了展望。     

超顺磁性纳米Fe3 O4的制备、表面改性方法与应用研究

对超顺磁性Fe<,3>O<,4>纳米粒子的制备方法及表面改性方法进行了总结,目前常用的方法有微乳液法、水热法、共沉淀法、溶胶.凝胶法及水解法,讨论了这些方法的优缺点,并对超顺磁性Fe<,3>O<,4>纳米粒子的应用作简单的介绍,对其进一步的研究进行了展望.     

产品开发

正发展磁性纳米材料前景广阔磁性纳米材料根据磁化率的大小分为抗磁性与顺磁性、铁磁性与反铁磁性等不同的磁性材料。比较成熟的磁性纳米材料制备技术是氧化铁纳米粒子的合成制备,主要有水溶液共沉淀、微乳液、水热和热分解等化学合成法,蒸发冷凝和机械球磨等物理合成法,以及生物合成法。磁性纳米材料已     

微乳液法制备Fe3O4/TiO2磁性纳米粒子

采用多元醇还原法制备出平均粒径为6.0 nm的Fe3O4磁性纳米粒子,以此磁性纳米粒子为核,在OP-10/正丁醇/环己烷/浓氨水反向微乳体系中制备出Fe3O4/TiO2磁性纳米复合粒子,通过XRD,TEM,VSM对复合粒子进行性能表征。结果表明,采用微乳液法能够制备出Fe3O4/TiO2磁性纳米复合粒子,并且包覆后比饱和磁化强度有所下降,但矫顽力仍趋近于0,显示超顺磁性。     

微乳液法制备Fe3O4/TiO2磁性纳米粒子

采用多元醇还原法制备出平均粒径为6.0 nm的Fe3O4磁性纳米粒子,以此磁性纳米粒子为核,在OP-10/正丁醇/环己烷/浓氨水反向微乳体系中制备出Fe3O4/TiO2磁性纳米复合粒子,通过XRD,TEM,VSM对复合粒子进行性能表征。结果表明,采用微乳液法能够制备出Fe3O4/TiO2磁性纳米复合粒子,并且包覆后比饱和磁化强度有所下降,但矫顽力仍趋近于0,显示超顺磁性。     

W／O微乳液制备纳米粒子的研究

介绍了微乳液的制备方法、微观结构模型和形成理论;介绍了W／O型微乳液在制备纳米粒子方面的应用,并对微乳液法制备纳米粒子的方法、原理、影响因素以及纳米粒子的表征方法进行了重点介绍。     

聚合物/纳米无机粒子复合材料的制备方法

概述了直接分散法、溶液共混法、溶胶-凝胶法等制备聚合物/纳米无机粒子复合材料的原理和主要工艺,重点介绍用超重力法和微乳液法制备纳米无机粒子。多种制备方法结合使用将非常有效。     

磁性纳米四氧化三铁制备研究进展

磁性纳米四氧化三铁是一种特殊功能的纳米材料,具有超顺磁性、小尺寸效应、量子隧道效应等特性。综述了磁性纳米四氧化三铁的制备方法,如共沉淀法、热分解法、水热法、溶剂热法、微乳液法、空气氧化法、静电纺丝法、微波法及其研究进展。对磁性纳米四氧化三铁的制备研究进展进行了展望。     

微乳液法制备纳米材料的研究进展

微乳液法制备纳米材料可以控制纳米粒子的大小和形状。本文综述了影响纳米粒子的主要因素和微乳液法制备纳米材料的最新研究进展。     

磁响应性ZnO/碳纳米管纳米复合材料的合成和光催化性能测试

用催化剂负载化制备了一种磁响应性光催化纳米复合材料.采用湿化学法制备纳米级超细活性氧化锌,用水热法制备出磁性Fe3 O4纳米粒子,将其超生分散在溶有碳纳米管的无水乙醇中,形成碳纳米管包裹Fe3 O4纳米粒子的微乳液.将该微乳液插于纳米氧化锌中,形成一种稳定体系,通过控制水解,使氧化锌纳米粒子于磁性Fe3 O4纳米粒子共...     

纳米磁性材料的制备及应用的新进展

介绍了纳米磁流体、纳米磁性颗粒、纳米磁性微晶及纳米磁性复合材料的制备方法并比较了各种方法的优缺点。并对纳米磁性材料的应用进行了概述,对其研究前景进行了展望。     

微乳液的结构及应用进展

系统阐述了微乳液的微观结构、相态、制备方法，并就微乳液在3次采油、纳米材料制备、有机化学反应、聚合反应、催化、分离过程等领域中的应用现状进行了详细探讨，并对微乳液的应用进行了展望。     

Water condensation-based nanoparticle charging system: Physical and chemical characterization

Abstract

A water condensation-based ion charging system has been developed to enhance both the charging efficiency and the concentration of sub-20?nm particles. This NanoCharger consists of a bipolar ion source followed by a parallel plate water-based condensation system, an embedded ion scavenger, and an aerodynamic focusing stage. Sufficient numbers of ions are transported through the system to attach to the formed droplets. An ion scavenger removes the ions immediately after the droplet formation to minimize multiple charging. A subsequent cold-walled condensation stage removes most of the water vapor, lowering the dew point to below 16?°C, while a set of focusing nozzles concentrates the droplets into ～10% of the flow. The flow is then slightly heated to evaporate the droplets. The physical enhancement of electrical charging was evaluated in the laboratory using mobility-selected particles, and found to provide ～40-fold enhancement over bipolar charging for 6–15?nm particles. Chemical artifacts were evaluated through thermal desorption chemical ionization mass spectrometry. Data comparing ion spectra for flow that passed through the NanoCharger to that obtained without it showed nearly equivalent ion spectra, indicating that no significant artifacts were introduced from the condensation–evaporation process.

Copyright © 2018 American Association for Aerosol Research     

Investigation of Surface Properties of Ultrafine Particles by Application of a Multistep Condensation Nucleus Counter

The fate of atmospheric ultrafine particles is determined by their size, chemical composition, and especially by their physical and chemical surface properties. To characterize the surface of ultrafine particles, their behavior as condensation nuclei can be used. Monodisperse ultra-fine particles with different surface structures were investigated by observing the onset of droplet formation at a fixed electrical mobility diameter. Droplet growth was detected by application of a multistep condensation nucleus counter (CNC). The particles were generated under well-controlled conditions and monodisperse fractions were obtained using an electrostatic classifier. For studying the influence of changes in the surface structure, ultrafine sulfuric acid droplets were coated with different organic materials. Different surface films required different supersaturations for droplet growth depending on the molecular structure and layer thickness of the material used for coating. Therefore it was concluded that certain compounds, enriched on the particle surface, affect condensation of water vapor in such a way that higher supersaturations are required in comparison to the particle core material. Additionally, it was observed that remarkably high supersaturations of water vapor were required for condensation on particles consisting of the following materials: metals, carbon, and Aerosil (spherical silica particles).     

惰性气体对高真空蒸发与冷凝过程的影响

采用Bhatnagar Gross Krood(BGK)模型方程,建立了计算多组分稀薄气体流动的数学模型和求解方法。应用该模型对邻苯二甲酸二丁酯(DBP)和癸二酸二丁酯(DBS)物系在有惰性气体存在条件下的一维蒸发和冷凝过程进行了数值模拟,考察了各操作工艺参数对该过程的影响。研究结果表明惰性气体分压远大于蒸发液体的饱和蒸气压时,蒸发效率趋近于零;升高蒸发温度、冷凝温度以及增大蒸发面和冷凝面之间的距离都将使得蒸发效率降低,其中冷凝温度的升高将使蒸发效率显著减小。     

反胶束微乳法制备无机功能纳米材料

介绍了微乳法制备无机纳米粒子的一般实验室方法 ,讨论了影响粒径及其分布的有关因素。比较了微乳液法与传统的制备方法的优劣 ,探讨了无机功能纳米材料研究进展并提出了今后研究工作的展望。     

Fe_3O_4/PANI抗氧化水基磁流体的制备与表征

在无氮气保护条件下,用化学共沉淀法制备了四氧化三铁(Fe3O4)纳米颗粒,并通过表面原位合成法将颗粒用聚苯胺(PANI)包裹,由此获得兼具磁性和导电性能的纳米四氧化三铁/聚苯胺(Fe3O4/PANI)材料。作者称其为Fe3O4/PANI抗氧化水基磁流体。透射电子显微镜(TEM)分析表明,该法制备的Fe3O4/PANI复合粒子的粒径在30~50 nm,其分散性能比包裹前的Fe3O4粒子明显改善。红外光谱(FTIR)和X射线衍射(XRD)测试结果发现,Fe3O4粒子及Fe3O4/PANI复合粒子具有不同的物态和晶相结构。对纳米复合粒子的抗氧化性能和磁性能的检测证实,原位合成的Fe3O4/PANI复合粒子不仅能有效防止在空气中被氧化,还可在磁场环境中实现快速富集、定位,为Fe3O4/PANI纳米复合粒子在生物医学领域的应用提供了可能。     

复杂逆流多效蒸发系统常规设计的模型与算法

建立了有冷凝水闪蒸和额外蒸汽引出的复杂逆流多效蒸发系统的数学模型 ,常规逆流多效蒸发模型只是该模型的一个特例。提出一种新算法———迭代法结合矩阵法求解模型并给出算法框图。迭代法结合矩阵法与目前较先进的Broyden法相比 ,具有对初值要求不高、收敛稳定性好、收敛速度快等优点 ,是求解多效蒸发问题的一种新的有效方法。算例表明 :模型可用于复杂逆流多效蒸发系统的快速求解 ;对三效逆流蒸发NaOH溶液系统 ,采用冷凝水闪蒸可节省加热生蒸汽 10 %左右 ,节能效果显著 ;逆流多效蒸发采用生蒸汽或引出额外蒸汽预热原料液不仅不会节能 ,反而造成热能损失     

Vacuum Separation Behavior of Pb from Copper-Rich Particles of Crushed E-Wastes

Due to lack of proper treatment methods, Pb pollution caused by improper treatment of electronic wastes (e-waste) has been attracting increasing attention. This paper investigates the separation behavior of Pb in the presence of Cu and other metallic particles (Cd, Bi, and Zn), in order to separate and recover various metals effectively from the copper-rich particles of crushed e-wastes. Vacuum metallurgy separation method is adopted to separate and recover Pb from the copper-rich particles of crushed e-wastes. Due to the variety and complexity of metals in copper-rich particles, this paper studies the effects of Cu, Cd, Bi, and Zn on vacuum separating and recycling of Pb. It is found that Cu particles have both a positive dispersing and a negative blocking effect on Pb evaporation. Cd can be evaporated preferentially, and then Pb can be subsequently separated for their huge vapor pressure gap. The formation of Pb-Bi alloy with a low vapor pressure makes the separation of Pb more difficult. As a result of different condensation characteristics, Pb and Zn can be evaporated together from Cu particles, and then be respectively condensed on different positions as pure Pb and Zn.     

纳米四氧化三铁化学法制备及其应用

纳米磁性材料作为一种新兴功能材料,由于其独特的物理化学性质,使其在物理、化学等方面表现出与常规磁性材料不同的特殊用途。纳米四氧化三铁就是其中一种多功能磁性材料,在磁记录材料、磁流体、催化、医药、颜料等方面具有广泛的应用。综述了近年来纳米磁性四氧化三铁的液相化学制备方法：共沉淀法、微乳液法、溶胶-凝胶法、溶剂热法等的研究现状以及最新的研究成果,对上述各种制备方法的优缺点进行了分析和比较。介绍了磁性纳米四氧化三铁在磁性液体、磁记录材料、催化、生物医药、微波吸收材料等方面的具体应用以及发展趋势,并提出其今后发展方向。