单质直接合成CuS及其催化分解高氯酸铵

室温下通过单质直接合成法,在氯化胆碱与乙二醇以物质的量比1∶2混合制得的低共熔溶剂中合成 了微米级的花状CuS球体。利用XRD、EDS、SEM 等表征手段对CuS进行了分析,并对花状CuS微球的形成机理作 了深入的讨论。同时,利用差热分析(DTA)技术考察了CuS微球对高氯酸铵(AP)热分解的催化效果。结果表明, 花状CuS微球对热分解高氯酸铵具有很好的催化效果。添加质量分数2%CuS的高氯酸铵的开始和结束分解温度 分别降低了30℃和132℃。     

Fabrication of Ni-, Co- and NiCo-coated graphite microspheres by heterogeneous precipitation

The precursors with NiCO₃·2Ni(OH)₂·2H₂O, Co₂(OH)₂CO₃, or both NiCO₃·2Ni(OH)₂·2H₂O and Co₂(OH)₂CO₃ coated graphite microspheres were prepared respectively by the aqueous heterogeneous precipitation using nickel sulfate, cobalt nitrate, sodium carbonate, ammonium bicarbonate and graphite microspheres as the main starting materials. Subsequently, Ni-, Co- and NiCo-coated graphite microspheres were successfully obtained by thermal reduction of the as-prepared precursors at 500 °C for 2 h, respectively. These metal-coated graphite microspheres were characterized with a smooth, cohesive surface consisting of fine metallic particles. Optimized precipitation processing parameters of the concentration of graphite microspheres (10 g/L), the rate of adding reactants (3 mL/min) and pH value (8.0) were determined by a trial and error method. The thermal analysis of the precursors was investigated by TG. Powders of the precursors and the resultant metal-(Ni, Co and NiCo alloy) coated graphite microspheres were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Funded by the Post-graduate Innovation foundation of Jiangsu Province of China (No. CX07B_085z)     

Two-step synthesis of TiC<Subscript>0.7</Subscript>N<Subscript>0.3</Subscript>@WC-MoC<Subscript>2</Subscript> core-shell microspheres and fabrication of TiC<Subscript>0.7</Subscript>N<Subscript>0.3</Subscript>@WC-MoC<Subscript>2</Subscript>-based cermets by SPS

The precursor with TiC0.7N0.3@WO3-MO3 microspheres were prepared by a novel method from the WO3-MoO3 sol dipping. Subsequently, TiC0.7N0.3@WC-MoC2 core-shell structural microspheres were successfully obtained by carburizing the precursor at 900 °C in a flowing mixture of CH4 (20 ml·min-1) and H2 (200 ml·min-1) for 2 h. Then TiC0.7N0.3@WC-MoC2-15Co cermets were prepared utilizing the core-shell powders by spark plasma sintering (SPS). Powders of the precursors with TiC0.7N0.3@WO3-MO3 microspheres, TiC0.7N0.3@WC-MoC2 microspheres and TiC0.7N0.3@WC-MoC2-15Co cermets were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The obtained TiC0.7N0.3@WC-MoC2 microspheres have a dense WC-MoC2 coatings shell. The thickness of the shell could be easily controlled by adjusting the number of sol dipping cycles. It was found that the TiC0.7N0.3@WC-MoC2 microspheres were more beneficial to fabricate the "core-rim" structures by SPS.     

Adsorption of BSA on carbon-coated Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> microspheres activated with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride

Carbon-coated Fe₃O₄ (Fe₃O₄/C) microspheres activated with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) were prepared, characterized and applied to adsorb bovine serum albumin (BSA). The prepared magnetic microspheres had spherical core-shell structure with a uniform and continuous carbon coating coupled with activation by EDC, and possessed superparamagnetic characteristics. The experimental results showed that the adsorption amount of BSA on the EDC-activated Fe₃O₄/C (Fe₃O₄/C-EDC) microspheres was higher than that on the Fe₃O₄/C microspheres. The maximum adsorption of BSA on Fe₃O₄/C-EDC microspheres occurred at pH 4.7, which was the isoelectric point of BSA. At low concentrations (below 1.0 M), salt had no noticeable effect on BSA adsorption. The BSA adsorption of Fe₃O₄/C-EDC microspheres had a better fit to the Langmuir model than the Freundlich isotherm and Temkin isotherm model, and the kinetic data were well described by the pseudo-second-order model. The adsorption equilibrium could be reached within 20 min. High desorption efficiency (97.6%) of BSA from Fe₃O₄/C-EDC microspheres was obtained with 0.5 M Na₂HPO₄ (pH 9.4) as the desorbent.     

Design and fabrication of superparamaganitic hybrid microspheres for protein immobilization

Superparamagnetic poly(styrene)-co-poly(2-acrylanmido-2-methyl propanesulfonic acid) (PSt-co-PAMPS) and poly(methylmethacrylate)-co-poly(glycidyl methacrylate) (PMMA-co-PGMA) microspheres with mean size of 170 nm were prepared by emulsion polymerization in the presence of oleic acid-coated Fe3O4 nanoparticles. The structures, morphologies, diameter and diameter distribution of the as-prepared microspheres were identified by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The saturation magnetizations of PSt-co-PAMPS and PMMA-co-PGMA microspheres are 21.94 and 25.07 emu/g, respectively. The as-synthesized magnetic microspheres were used for immobilization of Bovine serum albumin (BSA) by physical interaction and covalent interaction respectively. The equilibrium amount of BSA immobilized onto PMMA-co-PGMA microspheres was 86.48 mg/g microspheres in 90 min, while on PSt-co-PAMPS microspheres was 59.62 mg/g microspheres in 120 min.     

Controllable preparation and superior rate performance of spinel LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript> hollow microspheres as cathode material for lithium-ion batteries

Spinel LiMn₂O₄ microspheres and hollow microspheres with adjustable wall thickness have been prepared using controllable oxidation of MnCO₃ microspheres precursors and following solid reactions with lithium salts. Scanning electron microscopy (SEM) investigations demonstrate that the microsphere morphology and hollow structure of precursors are inherited. The effect of hollow structure properties of as-prepared LiMn₂O₄ on their performance as cathode materials for lithium-ion batteries has been studied. Electrochemical performance tests show that LiMn₂O₄ hollow microspheres with small wall thickness exhibit both superior rate capability and better cycle performance than LiMn₂O₄ solid microspheres and LiMn₂O₄ hollow microspheres with thick wall. The LiMn₂O₄ hollow microspheres with thin wall have discharge capacity of 132.7 mA·h·g^-1 at C/10 (14.8 mA·g^-1) in the first cycle, 94.1% capacity retention at C/10 after 40 cycles and discharge capacity of 116.5 mAh·g^-1 at a high rate of 5C. The apparent lithium-ion diffusion coefficient (D _app) of as-prepared LiMn₂O₄ determined by capacity intermittent titration technique (CITT) varies from 10^-11 to 10^-8.5 cm²·s^-1 showing a regular “W” shape curve plotted with test voltages. The Dapp of LiMn₂O₄ hollow microspheres with thin wall has the largest value among all the prepared samples. Both the superior rate capability and cycle stability of LiMn₂O₄ hollow microspheres with thin wall can be ascribed to the facile ion diffusion in the hollow structures and the robust of hollow structures during repeated cycling.     

多壁碳纳米管/氧化亚铜的制备及其对N-甲酰吗啉的光催化性能

采用液相还原法制备多壁碳纳米管/氧化亚铜（MWCNTs/Cu₂O）复合微球。利用傅立叶变换红外光谱仪（IR）、扫描电子显微镜（SEM）、X射线衍射仪（XRD）等对样品进行官能团分析、物相分析和形貌观察,结果表明：多壁碳纳米管以纵横穿插方式与氧化亚铜形成复合微球。对比氧化亚铜和多壁碳纳米管/氧化亚铜对目标有机物N-甲酰吗啉的光催化活性,结果表明：多壁碳纳米管/氧化亚铜复合催化剂的催化效果明显优于氧化亚铜。     

Magnetically Recoverable PEI/Titanate@Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> Photocatalysts: Fabrication and Photocatalytic Properties

The magnetically separable ternary polyetherimide/titanate@Fe₃O₄ (PTF) photocatalysts of special heterostructure between magnetite (Fe₃O₄) microspheres and titanates nanosheets modified by polyetherimide (PEI) were successfully fabricated via a simple facile hydrothermal deposition method. The as-prepared photocatalysts were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Transmission electron microscopy and UV-vis diffuse reflectance spectroscopy etc. The results showed that the as-fabricated material had a structure of Fe₃O₄ microspheres coated with titanates nanosheets modified by PEI. The special interfacial contact between 3D microsphere and 2D nanosheets in the nanoarchitectures was formed via electrostatic attraction. Furthermore, the resulted photocatalysts were tested by degradation reaction of methylene blue under visible light irradiation and demonstrated an enhanced performance than the pure Fe₃O₄ microspheres, and the photocatalytic activity enhanced with the molar ratio of Fe₃O₄ microspheres and modified titanate gradually, which was attributed to the expansion of the surface area and the different electrostatic contact between the Fe₃O₄ microspheres and titanate nanosheets. Moreover, the obtained results revealed the high yield magnetic separation and efficient reusability of PTF-5 (96.7%) over 3 times reuse.     

Preparation of Hollow Porous HAP Microspheres as Drug Delivery Vehicles

Hollow HAP microspheres in sub-millimeter size were prepared and investigated as a drug delivery vehicle. The LCB （lithium-calcium borate） glass microspheres, which were made through flame spray process, were chosen as precursor for hollow HAP microspheres. The LCB glass microspheres reacted with phosphate buffer （K2HPO4） solution for 5 days at 37 ℃. During the reaction the Ca-P-OH compound precipitated on the surface of LCB glass microspheres and formed porous shells. Then the microspheres turned to be hollow ones with the same diameter as the glass microspheres after LCB glass run out in the chemical reaction. After heat-treated at 600 ℃ for 4 h, the Ca-P-OH compound became HAP, thus the hollow HAP microspheres were produced. The mechanism of forming hollow HAP microspheres through the chemical reaction between phosphate buffer and LCB glass was confirmed by the XRD analysis. The microstructure characteristics of the hollow, porous microspheres were observed by SEM.     

Coating of Fe, Ni on α-alumina microspheres by heterogeneous precipitation

1INTRODUCTION Themagneticmetal coatedceramicoxides,core shellstructuralcompositematerials,inwhichthinmetallicfilmsarecoatedonaceramicoxide matrixwithmicrometerparticlesizes,areattrac tiveduetothecombinationofthefunctionalchar acteristicsofmetalsandmechanicalpropertiesoftheceramicmatrix.Theceramic basedtransition metal coated,core shellcompositessuchasNi coatedAl2O3[1],Fe coatedAl2O3[2],FeNi coated Al2O3[3]orCoFe coatedSiO2[4],havebeenfoundtoexhibitinterestingfunctionalperformancesdue…     

Preparation of Bauxite Ceramic Microsphere

Ceramic microspheres were prepared by using Chinese bauxite as raw materials through the centrifugal spray drying method. The control technology of microsphere size, degree of sphericity was researched. The ceramic microspheres were sintered by a double sintering process. The microstructure and composition of ceramic microsphere were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and X-ray energy spectroscopy. The results show that the degree of sphericity of the ceramic microsphere was good and the particle size was 10-100 μm. The XRD analysis reveals that the main crystalline phase of the ceramic microsphere was a-Al2O3 and mullite （3Al2O3·2SiO2）. The product can be used as reinforced material for composite material, especially for antiskid and hard wearing aluminum alloy coating.     

Electrochemical Sensing of Heavy Metal Ions based on Monodisperse Single-crystal Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> Microspheres

Single-crystal Fe₃O₄ with monodisperse microspheres structure has been used for individual electrochemical detection of heavy metal ions. Morphology and structure of the as-prepared Fe₃O₄ microspheres were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Meanwhile the electrochemical properties of the Fe₃O₄ microspheres modified glass carbon electrodes (GCE) were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and the enhanced electrochemical response in stripping voltammetry for individual detection of Pb(II), Hg(II), Cu(II), and Cd(II) was evaluated using square wave anodic stripping voltammetry (SWASV). With high specific surface area and excellent catalytic activity toward heavy metal ions, the as-prepared monodisperse and single-crystal Fe₃O₄ microspheres show a preferable sensing sensitivity (22.2 μA/μM) and limit of detection (0.0699 μM) toward Pb(II). Furthermore, the electrochemical sensor of Fe₃O₄ microspheres exhibits excellent stability and it also offers potential practical applicability for the determination of heavy metal ions in real water samples. This study provides a potential simple and low cost iron oxide for the construction of sensitive electrochemical sensors applied to monitor and control the pollution of toxic metal ions.     

Role of ammonium sulfate in sulfurization flotation of azurite: Inhibiting the formation of copper sulfide colloid and its mechanismOA

In this study, the role of(NH₄)₂SO₄ during the sulfurization of azurite and its response to flotation were investigated. The flotation results showed that adding(NH₄)₂SO₄ prior to sulfurization decreased the formation of colloid in flotation pulp, and the floatability of the suppressed azurite caused by excess sodium sulfide was restored. After adding(NH₄)₂SO₄ prior to sulfurization, the formation ...     

Hollow calcium carbonate microspheres prepared in the presence of polyoxyethylene （20） sorbitan monolaurate and sodium dodecyl sulfate

Hollow calcium carbonate(CaCO3) microspheres were prepared in aqueous solution with the presence of polyoxyethylene(20) sorbitan monolaurate(Tween20) and sodium dodecyl sulfate(SDS).The microspheres were characterized with X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscope(TEM).The X-ray diffraction data showed that the hollow CaCO3 microsphere consisted of calcite crystals.The influence of Tween20 and SDS concentrations on the morphology of CaCO3 crystals was investigated.The results suggested that the"core-shell model"of Tween20/SDS micelle aggregated as templates,which could control the growth of hollow CaCO3 microspheres.The interaction between mixed surfactants and calcium ions played a critical role in organizing calcium carbonate in microscopic level.     

Preparation and in vitro release properties of mercaptopurine drug-loaded magnetic microspheres

Magnetic Fe304 nanoparticles were synthesized by co-precipitation method and the mercaptopurine （MER） drug-loaded magnetic microspheres were obtained through emulsion cross-linking methods. The efficiency of this approach was evaluated in terms of drug loading content （DLC）, encapsulation efficiency （EE） and delivery properties in vitro, determined by high performance liquid chromatograph （HPLC）. The microspheres showed good DLC values of 11.8%, as well as good EE values of 79.4%. The in vitro drug release study was carried out in phosphate buffer solution （PBS） simulated body fluid, at 37 ~C with pH=7.4. The release profiles showed an initial fast release rate, which decreased as time progressed and about 84 % had been released after 48 h. The experimental results indicated that the prepared magnetic microspheres may be useful for potential applications of MER for magnetically targeted chemotherapy.     

The Synthesis and Eleetrorheologieal Properties of BaTiO3-coated PMMA Mierospheres

Coated-PMMA microspheres consisting of poly （methyl methacrylate）（PMMA） core and barium titanate （BaTiO3） shell were synthesized by the modified sol-gel processing and then adopted as an electrorheological （ER） materials. The structure and morphology of coated powders were chyfecterized by SEM and FT-IR; the shear stress of the suspensions of coated-PMMA particles and pure PMMA particles in silicone oil with a 20 vol% were investigated. The results show that the BaTiO3 coated PMMA microspheres based suspension in silicone oil exhibited typical ER behavior and stronger ER effects.     

Novel MoS<Subscript>2</Subscript> microspheres formed by solid-state assembly of ultrathin nanosheets

The MoS₂ microspheres with high specific surface area assembled by ultrathin nanosheets have been successfully synthesized by a facile and environmentally friendly reaction in a closed reactor at moderate temperatures. The solid-state assembly was realized by a simple calcination process, and the annealing temperature played a key role in the formation of the final microspheres. The influences of reaction temperature were carefully investigated. A possible formation mechanism about the solid-state assembly was proposed based on the experimental results.     

Electrocatalytic activity of tungsten trioxide microspheres, tungsten carbide microspheres and multi-walled carbon nanotube-tungsten carbide composites

Tungsten trioxide micropheres were prepared by spray pyrolysis, and tungsten carbide microspheres were produced by spray pyrolysis-low temperature reduction and carbonization technology. Multi-walled carbon nanotube-tungsten carbide composites were prepared by the continuous reduction and carbonization process using multi-walled carbon nanotubes (MWCNTs) and WO₃ precursor by molecular level mixing and calcination. The morphology and structure of the samples were characterized by scanning electron microscope and transmission electron microscope. Furthermore, the crystal phase was identified by X-ray diffraction. The electrocatalytic activity of the sample was analyzed by means of methanol oxidation. Tungsten carbide microspheres were catalytic active for methanol oxidation reaction. Nevertheless tungsten trioxide microspheres and multi-walled carbon nanotube-tungsten carbide composites were not catalytic active for methanol oxidation reaction. These results indicate that tungsten carbide micropheres are promising catalyst for methanol oxidation.     

Preparation and self-assembly of chitosan/carbon microsphere composite

Carbon-based films were synthesized by self-assembly of chitosan-encapsulated carbon microsphere (CMS@CS) composite. First, carbon microspheres (CMSs) prepared by chemical vapor deposition were modified by HNO3 and H2O2. Second, oxidized CMSs were modified by chitosan (CS). Finally, CMS@CS was self-assembled by vertical deposition, in which suspension concentration and deposition temperature on the quality of self-assembling film were investigated. Field emission scanning electron microscopy, atomic force microscopy, X-ray diffraction, thermogravimetry, and Fourier transformation infrared spectrometry were employed to characterize the morphology and structure of the samples. The results show that CMSs modified by CS had uniform particle size and good dispersion, CMS@CS was self-assembled into a dense film, the film thickened with increasing suspension concentration at fixed temperature, and more ordered film was obtained at 1 wt% of suspension concentration and 50 ℃. The ultraviolet-visible absorption spectra show that the absorbance of CMS@CS film grew steadily with increasing suspension concentration and that the CMSs with oxygen-containing groups have a good assembling performance to form composite films with CS.     

Effects of Heat Treatment Temperature and Time on Structure and Static Magnetic Property of W-type Ferrite Hollow Microspheres

Hollow spheres of hexagonal ferrite BaCo2Fe16O27 were fabricated through a spray pyrolysis technique using co-precipitation ferrite powder precursor as materials, followed by calcinations in an air atmosphere. The phase composition, micro-morphology, and static magnetic property of the particles were measured by XRD, SEM, and VSM. The results indicate that the method for preparation of ferrite hollow microspheres (FHM) results in a broad particles size distribution. The density of FHM decreased from 5.31 g/ cm3 to 2.31 g/cm3. When the heating rate was 5 ℃/min, and temperature was 1 200 ℃ for 4 hours, pure W-type ferrites were formed. With the heat treatment temperature and time increasing, the crystal structure becomes perfect, the saturation magnetization is increased and the coercive force is decreased.