Magnetically induced agitation in liquid‐liquid‐magnetic nanoparticle emulsions: Potential for process intensification

Microscopic mixing using magnetic nanoparticles (MNP) unveils exciting ramifications for process intensification in chemical engineering. This study explores the use of oil‐in‐water MNP emulsions to achieve mixing in a nonmagnetic continuous phase tantamount to that occurring in equivalent dilute ferrofluid suspensions. To assess the technique, measurements of the torque exerted by ferrofluid emulsions and suspensions of equal magnetic content were performed in rotating, oscillating, and static magnetic fields. Results show that momentum transfer is fairly alike in amplitude and proportionality for the two types of systems of equal magnetic content under the three types of magnetic fields. This implies that momentum of spinning nanoparticles in the emulsions is transferable to the oil droplets containing them which, in return is then transferred to surrounding nonmagnetic liquid. The magnitude of the resulting mixing allows for the foresight of a versatile MNP mixing technology completely separated from the target phase being mixed. © 2013 American Institute of Chemical Engineers AIChE J, 60: 1176–1181, 2014     

Exploiting Size-Dependent Drag and Magnetic Forces for Size-Specific Separation of Magnetic Nanoparticles

Realizing the full potential of magnetic nanoparticles (MNPs) in nanomedicine requires the optimization of their physical and chemical properties. Elucidation of the effects of these properties on clinical diagnostic or therapeutic properties, however, requires the synthesis or purification of homogenous samples, which has proved to be difficult. While initial simulations indicated that size-selective separation could be achieved by flowing magnetic nanoparticles through a magnetic field, subsequent in vitro experiments were unable to reproduce the predicted results. Magnetic field-flow fractionation, however, was found to be an effective method for the separation of polydisperse suspensions of iron oxide nanoparticles with diameters greater than 20 nm. While similar methods have been used to separate magnetic nanoparticles before, no previous work has been done with magnetic nanoparticles between 20 and 200 nm. Both transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis were used to confirm the size of the MNPs. Further development of this work could lead to MNPs with the narrow size distributions necessary for their in vitro and in vivo optimization.     

Synthesis of Ni nanoparticles with controllable magnetic properties by atmospheric pressure microplasma assisted process

An atmospheric pressure microplasma technique is demonstrated for the gas phase synthesis of Ni nanoparticles by plasma‐assisted nickelocene dissociation at different conditions. The dissociation process and the products are characterized by complementary analytical methods to establish the relationship between operational conditions and product properties. The innovation is to show proof‐of‐principle of a new synthesis route which offers access to less costly and less poisonous reactant, a higher quality product, and a simple, continuous and pre/post treatment‐free manner with chance for fine‐tuning “in‐flight.” Results show that Ni nanoparticles with controllable magnetic properties are obtained, in which flexible adjustment of product properties can be achieved by tuning operational parameters. At the optimized condition only fcc Ni nanoparticles are formed, with saturation magnetization value of 44.4 mAm²/g. The upper limit of production rate for Ni nanoparticles is calculated as 4.65 × 10^?3 g/h using a single plasma jet, but the process can be scaled‐up through a microplasma array design. In addition, possible mechanisms for plasma‐assisted nickelocene dissociation process are discussed. © 2017 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 64: 1540–1549, 2018     

Classification of Magnetic Nanoparticle Systems—Synthesis,Standardization and Analysis Methods in the NanoMag Project

This study presents classification of different magnetic single- and multi-core particle systems using their measured dynamic magnetic properties together with their nanocrystal and particle sizes. The dynamic magnetic properties are measured with AC (dynamical) susceptometry and magnetorelaxometry and the size parameters are determined from electron microscopy and dynamic light scattering. Using these methods, we also show that the nanocrystal size and particle morphology determines the dynamic magnetic properties for both single- and multi-core particles. The presented results are obtained from the four year EU NMP FP7 project, NanoMag, which is focused on standardization of analysis methods for magnetic nanoparticles.     

模拟移动床技术在中药有效成分分离中的应用

模拟移动床色谱(simulatedmovingbedchromatography)或简称模拟移动床(SMB)是连续色谱的一种,是模拟移动床技术和色谱技术的结合,是以模拟移动床的运转方式来实现色谱的连续分离。该文主要从模拟移动床的发展、结构、原理及其特点、难点和该项技术在中药有效成分分离中的应用等几个方面做一介绍。引用文献20篇。     

磁场对氨水吸收烟气中CO2的促进作用

开发了一种新型磁场辅助氨法烟气脱碳技术。含碳烟气通入混有磁性颗粒的氨水溶液,在外加磁场的作用下发生脱碳反应。对该技术的运行特性开展了实验研究。结果表明,外加8 mT恒稳磁场,2 g·L^-1纳米级Fe₃O₄颗粒,氨水的CO₂脱除效率比不添加磁场和颗粒时最多可提高8.8%。外加磁场可以有效提高低浓度氨水的CO₂脱除效率。在模拟烟气流量增加时,外加磁场能有效减缓CO₂脱除效率下降的趋势。同时,外加磁场使得CO₂脱除效率曲线向低温方向移动5℃,有助于提高低温条件下的CO₂脱除效率。磁场可提高气液接触效率、降低相间传质阻力、增强氨水反应活性,从而提高氨水吸收CO₂性能。     

Molecular characterization of statistical copolymers: 1. Potential and limitations of full adsorption–desorption procedure in separation of statistical copolymers

Dynamic integral desorption isotherms for a series of poly(methyl methacrylate) homopolymers and poly(methyl methacrylate)–polystyrene statistical copolymers were measured. Nonporous silica was the full adsorption–desorption (FAD) column packing and various adsorption‐promoting and desorption‐promoting liquids were used. The aim of this study was to evaluate the applicability of the FAD approach for separation of statistical copolymers. The effects of the adsorbing liquid and desorbing liquid nature were demonstrated on the positions and shapes of desorption isotherms. The desorption isotherms also strongly depended on both (co)polymer molar mass and copolymer chemical composition. This indicates large fractionation potential of the FAD procedure. Simultaneously, the interference of both above parameters prevents the direct use of FAD for fractionation of the copolymers. It is anticipated that the fractionation and/or reconcentration potential of the FAD procedure can be very effectively utilized in combination of FAD with size‐exclusion chromatography and/or with gradient elution liquid adsorption chromatography. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 857–864, 2000     

PET基磁性膜材料的制备与性能表征

用共沉淀法制备出具有磁性的Fe3O4纳米粒子水溶液。红外光谱和XRD表明,纳米粒子是Fe3O4且其粒径在15 nm左右。通过磁滞回线得到纳米粒子比饱和磁化强度σr=56.58 emu/g。对PET薄膜进行预处理和阴离子化后,在PET表面交替吸附聚电解质聚二甲基二烯丙基氯化铵(PDDA)和纳米粒子水溶液,由于PDDA的存在,Fe3O4纳米粒子能均匀地被吸附在PET表面,形成PET基磁性膜材料,且吸附的强度较强。该材料的矫顽力为41.11 Oe,剩余磁化强度为0.66 emu,与Fe3O4纳米粒子一样,具有超顺磁性。     

甲醇甲苯烷基化流化床反应器的数值模拟

利用甲醇甲苯烷基化工艺生产对二甲苯具有良好的应用前景。甲醇甲苯烷基化催化剂较易积炭失活，且反应存在明显热效应。流化床因传热传质性能好、易实现催化剂连续再生，适合用作甲醇甲苯烷基化反应器。本文采用离散颗粒模型，对甲醇甲苯烷基化流化床反应器进行了数值模拟研究，重点考察了进料比、反应压力、分段进料对反应特性的影响。结果表明，当甲苯进料量给定时：降低反应物中甲苯甲醇比可有效提升对二甲苯产率和选择性，但产物中对二甲苯和烯烃摩尔比值较低；提高反应压力可显著提升甲醇和甲苯转化率，但会降低对二甲苯选择性；在低苯醇比基础上采用甲醇分段进料方式不仅可有效提高甲苯利用率，还可灵活调节产物中对二甲苯和烯烃比率；流化床反应器气体返混不利于获得高对二甲苯选择性，且操作条件变化会造成流化床反应器内气固流动改变，导致气固接触效率或反应物局部分压发生改变，这亦将对反应转化特性造成显著影响。这些结果对于流化床反应器优化和放大具有一定的指导意义。     

Solvothermal synthesis and characterization of ytterbium/iron mixed oxide nanoparticles with potential functionalities for applications as multiplatform contrast agent in medical image techniques

A solvothermal route to prepare Glutathione capped hybrid ytterbium/iron oxide nanoparticles with potential applications as multiplatform contrast agent in medical image techniques has been developed. The influence of ytterbium/iron molar ratio used as precursor, as well as the degree of the autoclave filling on the structural and morphological characteristics of the obtained nanoparticles has been extensively studied. Although all nanoparticles present similar composition, with YbFeO₃ being the majority phase, size and morphology of the as synthetized nanoparticles are highly influenced by the critical temperature and by the over -saturation reached during the solvothermal process. We have demonstrated that glutathione properly functionalizes the hybrid nanoparticles, increasing their colloidal stability and decreasing their cytotoxicity. Additionally, they show good imaging in magnetic resonance and X-ray computerized tomography, thereby indicating promising potential as a dual contrast agent. This work presents, for the first time, glutathione functionalized ytterbium/iron oxide nanoparticles with potential applications in Biomedicine.     

Magnetic properties and self-heat behaviors of core@shell structured MnFe2O4@Fe3O4 magnetic nanoparticles

In this work, a facile solvothermal synthesis of MnFe₂O₄ nanoparticles is followed by an easy and reproducible process to envelop the synthesized MnFe₂O₄ nanoparticles with iron oxide nanoparticles using ethanol and ethylene glycol as solvents. All prepared MnFe₂O₄ nanoparticles show a homogenous distribution of spherical particles with an average particle size between 12 and 16 nm. The encapsulation process of MnFe₂O₄ nanoparticles does not affect their homogenous distribution with a very thin layer of Fe₃O₄ on the shell structure. The magnetic properties showed a superparamagnetic character with enhanced magnetic properties of MnFe₂O₄@Fe₃O₄ compared to pure MnFe₂O₄, which has been verified by magnetization and electron spin resonance. The heating efficiency of the prepared samples was evaluated in terms of the specific loss power using the calorimetric method. The synthesized MnFe₂O₄ nanoparticles show a significantly high value of about 72 W/g, which got doubled in the core@shell structure and reached 140 W/g at 189 kHz and 10kA/m of the magnetic field.     

Large‐scale isolation and purification of C‐phycocyanin from the cyanobacteria Anabaena marina using expanded bed adsorption chromatography

BACKGROUND: Phycobiliproteins are water soluble proteins useful as fluorescent markers of cells and macromolecules, and as natural colorants, and are anticarcinogenic. Although phycobiliproteins have many applications, their use is limited by the high cost of the purified macromolecules, mainly related with the cost of extraction and purification. In this study a fast and scalable method for preparative extraction and purification of C‐phycocyanin (C‐PC) from Anabaena marina is developed. RESULTS: The method developed consists in the extraction of phycobiliproteins using repeated single contact strategy, separation being performed by expanded bed adsorption (EBA) chromatography using Streamline‐DEAE. Optimal conditions for EBA were obtained at small scale, using a 15 mm internal diameter column, these being a sample load of 0.9 mg C‐PC mL^?1 adsorbent, an expanded bed volume twice the settled bed volume and a sample viscosity of 1.109 mP. The process was then scaled up 36 times, the success of the scale‐up process being verified. Finally, to obtain pure C‐PC conventional ion‐exchange chromatography was utilized. CONCLUSION: Small diameter columns was shown to be useful to simulate the behavior of larger diameter columns for use in scaled up systems. Expanded bed adsorption was demonstrated to be a scalable technology allowing large quantities of C‐PC to be obtained, maintaining high protein recovery while reducing both processing cost and time. The proposed methodology allows recovery of more than 62% of the C‐PC contained in the biomass in the form of pure C‐PC concentrates. Copyright © 2010 Society of Chemical Industry     

Preparation and evaluation of chitosan/β‐cyclodextrin magnetic nanoparticles as a photodegradable and hydrophobic drug delivery carrier

In this study, novel tumor targeting nanocarriers comprised of chitosan (CS)/β‐cyclodextrin (β‐CD) magnetic nanoparticles were prepared to improve the photodegradable stability and bioavailability of hydrophobic drug. Resveratrol (Res) with photodegradable and hydrophobic properties was selected as a model drug. The photodegradation rate of Res in Fe₃O₄ nanoparticles solution was 7.8 times lower than that in the ethanol solution_. In addition, the value of the saturation magnetization of CS/β‐CD nanoparticles was found to be 19.56 emu/g with characteristic of superparamagnetism. Approximately 90% Res was entrapped into the CS/β‐CD magnetic nanoparticles with the size distribution ranging from 200 to 359 nm, and the nanoparticles were spherical in shape with high zeta potentials. Furthermore, the formation of CS/β‐CD nanoparticles showed a sustained release in vitro. These results indicated that the obtained CS/β‐CD magnetic nanoparticles were a promising magnetic targeting carrier for photodegradable and hydrophobic drugs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45076.     

Magnetic resonance of the NiFe2O4 nanoparticles in the gigahertz range

We report an adjustable magnetic resonance frequency from 1.45 to 2.54 GHz for NiFe₂O₄ nanoparticles which were prepared by a sol–gel process. X-ray diffraction and scanning electron microscopy results indicate that the samples are polycrystalline nanoparticles, and the size of the particles increases obviously with the thermal treatment temperature. The consequence of the surface composition suggests that the oxygen defects are present in the nanoparticle surface, and this surface magnetic state can show a strong surface anisotropy. With decreasing size of the particle, the surface magnetic effect is predominant, resulting in an increase of resonance frequency for NiFe₂O₄ nanoparticles. This finding provides a new route for NiFe₂O₄ materials that can be used in the gigahertz range.     

填料粒径对制备色谱生产的影响

随着绿色精细化工工业的发展,对制备色谱和模拟移动床色谱(SMBC)的需求越来越大。填料粒径的选择是制备色谱和模拟移动床色谱分离中的关键问题。填料粒径主要从柱效和压力两方面影响着制备色谱的应用。压力影响着运行成本,柱效影响着分离效果,但两者又互相制约。该文利用板高曲线和压力变化曲线斜率积对填料性能进行了比较。斜率积消除了填料粒径的影响,却又联系着其他与柱压力和柱效相关的因素。利用斜率积来评价填料性能对问题的分析更加深入。该文通过对不同粒径填料所填充柱的孔隙率、柱压和柱效的比较发现,随填料粒径减小,柱压力的上升幅度小于随填料粒径平方反比例增大的幅度,理论塔板高度减小。从银杏黄酮的模拟移动床色谱分离结果可以看出,使用粒径为20~25μm的填料,其产品纯度低于使用粒径为30~40μm的填料。     

磁性纳米颗粒-微波辐射对稠油O/W乳状液的协同破乳

首先分析了微波辐射功率和辐射时间对磁性纳米粒子协同破乳的影响规律,在此基础上,利用生物显微镜、接触角测量仪、zeta电位分析仪等分别测量了微波作用前后油滴的分布以及磁性纳米粒子的润湿性和带电性,从而揭示了微波和磁性纳米粒子的协同破乳机理。实验结果表明：磁性纳米粒子作用下,微波辐射参数过高或者过低都会对磁性纳米粒子破乳产生抑制作用,只有在最优辐射参数范围内,微波才会促进磁性纳米粒子的破乳,且当纳米Ni浓度为150mg/L,微波辐射参数为400W、30s时,乳状液的分水率达到最高值102.56%,而在相同微波辐射参数下,Co₃O₄浓度为125mg/L,乳状液的分水率达到最大值106.06%。该工作为磁性纳米颗粒-微波辐射协同破乳技术的发展提供试验和理论依据。     

Materials Characterization of Feraheme/Ferumoxytol and Preliminary Evaluation of Its Potential for Magnetic Fluid Hyperthermia

Feraheme, is a recently FDA-cleared superparamagnetic iron oxide nanoparticle (SPION)-based MRI contrast agent that is also employed in the treatment of iron deficiency anemia. Feraheme nanoparticles have a hydrodynamic diameter of 30 nm and consist of iron oxide crystallites complexed with a low molecular weight, semi-synthetic carbohydrate. These features are attractive for other potential biomedical applications such as magnetic fluid hyperthermia (MFH), since the carboxylated polymer coating affords functionalization of the particle surface and the size allows for accumulation in highly vascularized tumors via the enhanced permeability and retention effect. This work presents morphological and magnetic characterization of Feraheme by transmission electron microscopy (TEM), Energy dispersive X-ray spectroscopy (EDX), and superconducting quantum interference device (SQUID) magnetometry. Additionally, the results of an initial evaluation of the suitability of Feraheme for MFH applications are described, and the data indicate the particles possess promising properties for this application.     

新型多组分连续制备色谱系统--阵列式柱色谱

本文介绍了一种新型多组分连续制备色谱系统———阵列式柱色谱。该系统是在综合了模拟移动床色谱和旋转环状色谱的工作原理的基础上开发出来的 ,主要由控制部分、流体输送部分、分离部分、检测部分和收集部分所组成。在分离部分中 ,本系统用色谱柱阵列代替了旋转环状色谱的环形填料层 ,即避免了溶质横向扩散和动密封问题 ,又可以根据实际生产需要增减色谱柱数目 ;在收集部分中 ,使用了专门为本系统设计的收集器实现了所有色谱柱流出液的集中收集 ;本系统采用将试验和生产一体化的设计 ,通过将单柱模式下的使用在线检测得出的优化分离条件应用到多柱模式中 ,实现了系统的柔性设计 ,降低了设备成本 ;用户可以通过使用装有系统控制软件的上位机与系统进行实时交互 ,大大提高了系统运行自动化程度 ,简化了操作。具有上述优点的本系统必将有着广泛的应用前景     

纳米水基磁性液体在肿瘤治疗领域的研究进展

结合作者在纳米磁性液体方面的研究经历,介绍了生物医学应用领域纳米磁性粒子的组成结构及特点,指出高分子改性纳米磁性粒子具有生物相容性好、稳定性强、载药量高的优点,并对目前高分子改性纳米四氧化三铁颗粒的制备方法及特点进行了对比分析。指出进一步研制磁响应性强、载药量高、粒度分布均匀的纳米磁性粒子,使之对癌细胞具有亲和作用,尽量避免对毛细血管网状内皮系统的清除,是未来肿瘤治疗领域纳米磁性粒子的研发目标,并对目前制备方法中存在的不足提出了改进的建议。     

离子液体修饰超顺磁性纳米颗粒用于青霉素G酰化酶固定化(英文)

Functionalized ionic liquids containing ethyoxyl groups were synthesized and immobilized on magnetic silica nanoparticles(MSNP) prepared by two steps,i.e.,Fe3O4 synthesis and silica shell growth on the surface.This magnetic nanoparticle supported ionic liquid(MNP-IL) were applied in the immobilization of penicillin G acylase(PGA).The MSNPs and MNP-ILs were characterized by the means of Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and vibrating sample magnetometer(VSM).The results showed that the average size of magnetic Fe3O4 nanoparticles and MSNPs were ~10 and ~90 nm,respectively.The saturation magnetizations of magnetic Fe3O4 nanoparticles and MNP-ILs were 63.7 and 26.9 A?m2?kg?1,respectively.The MNP-IL was successfully applied in the immobilization of PGA.The maximum amount of loaded enzyme was about 209 mg?g?1(based on carrier),and the highest enzyme activity of immobilized PGA(based on ImPGA) was 261 U?g?1.Both the amount of loaded enzyme and the activity of ImPGA are at the same level of or higher than that in previous reports.After 10 consecutive operations,ImPGA still main-tained 62% of its initial activity,indicating the good recovery property of ImPGA activity.The ionic liquid modified magnetic particles integrate the magnetic properties of Fe3O4 and the structure-tunable properties of ionic liquids,and have extensive potential uses in protein immobilization and magnetic bioseparation.This work may open up a novel strategy to immobilize proteins by ionic liquids.