Fabrication and characterization of copper nanoparticles using thermal reduction: The effect of nonionic surfactants on size and yield of nanoparticles

Thermal reduction has been applied to the preparation of copper nanoparticles (Cu-NPs) using three kinds of nonionic surfactants (Triton X-100, Tween-80, and dodecylamine). The Cu-NPs were formed by decomposition of copper(II) oxalate in presence of triphenylphosphine. The effect of the surfactants on the formation of the Cu-NPs was studied via X-ray diffraction, scanning electron microscopy, energy dispersive analysis of X-rays, transmission electron microscopy, thermogravimetric differential thermal analyses, and Fourier transform infra-red spectroscopy. It is shown that the Cu-NPs have an fcc crystal structure. Depending on the surfactant used, Cu-NPs with diameters between 8 and 20 nm can be prepared. The smallest Cu-NPs (8 nm) were formed in the presence of micelles of dodecylamine (yield 49%), while the largest particles (20 nm) were obtained with Triton X-100 (yield 99%). The use of Triton X-100 results in the highest yield and most uniform Cu-NPs.     

水热法合成纳米氧化铜粉体及其性能表征

氧化铜粉体广泛用于电极材料[1 ] 、玻璃、催化剂 (载体 )等领域。粒子的超细化 ,可以显著的改善氧化铜的应用性能。制备纳米氧化铜的方法有固相合成法[2 ] 、沉淀转化法[3] 和络合沉淀法[4] 。本文采用水热法一步合成了纳米氧化铜粉体 ,所得粉体粒度均匀 ,操作简便 ,易于工业化生产。1　实验部分1 1　样品制备将硝酸铜 (分析纯 ,北京化工二厂 )配成浓度为 1 .0ｍｏｌ·Ｌ- 1 的溶液 ,按物质的量比为 2∶1加入浓度为 1 .0ｍｏｌ·Ｌ- 1 的尿素 (分析纯 ,上海试剂一厂 )溶液 ,然后在 95℃～ 1 2 5℃下加热溶液进行反应。由于水溶液在 1 0 0…     

壳聚糖-海藻酸盐纳米粒子的制备及其对BSA的载药与释放特性

带相反电荷的聚电解质在水溶液中能通过静电相互作用自组装形成壳聚糖-海藻酸盐纳米粒。利用动态光散射纳米粒度分析仪考察了钙离子及壳聚糖对粒子粒径的影响。结果表明：钙离子的存在可使粒子粒径从268．5nm降为203．4nm,但随着钙离子含量的继续升高,粒径迅速增大,当钙离子浓度大于0．45g／L时形成凝胶。壳聚糖含量的增加和蛋白的包裹均会使粒径增大。所制备的纳米粒对BSA具有较高的包栽能力,并有一定的缓释作用。当壳聚糖投料量增加时,可使BSA在pH=7．4的PBS中的释放减慢。     

不同结构形态的NdOHCO3中Nd3+的增强电子拉曼光谱研究

利用X射线粉末衍射、场发射电子扫描显微术和透射电子显微术TEM,对不同方法制备的形态、颗粒大小不同的MdOHCO3进行钕离子的增强电子拉曼光谱和FT-IR光谱研究,发现结构形态不同的NdOHCO3由于配位环境变化,导致钕离子的电子拉曼光谱在2600～1600cm-1附近拉曼谱带的峰形、峰位和峰的数目产生显著变化.     

Synthesis and Characterizations of Copper Oxide Nanoparticles Within Zeolite Y

Copper oxide nanoparticles within zeolite Y have been synthesized by a procedure comprising (i) ion-exchange of copper ions into the zeolite, (ii) precipitation of copper ions with sodium hydroxide within the supercages of the zeolite, and (iii) calcination. The products were characterized by X-ray diffraction, scanning electron microscope, energy-dispersive X-ray spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The particle size of CuO products are 20?nm.     

Efficient alternative of antimicrobial nanocomposites based on cellulose acetate/Cu-NPs

The current research presents an efficient, cheap, and safe antimicrobial material for widespread use based on copper nanoparticles (Cu-NPs) loaded on cellulose acetate (CA) matrix. A reduction process of CuSO₄·5H₂O has been performed to prepare Cu-NPs. The nanosized copper particles included oxidized Cu (15–20 nm). Two different loads of Cu-NPs were used in this study, 2% and 6% mol.%. The presence of Cu-NPs incorporated with CA films slightly affected the tensile index of the films, where low and high-loaded Cu-NPs enhanced the tensile index by small values ranged from 0.640 to 0.650 and 0.667, respectively. A study on the antibacterial activity of these nanocomposites was carried out for Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. It has been found that CA containing Cu-NPs (2%) exhibited the highest antimicrobial activity against all test microbes including S. aeureus (21 mm), P. aeruginosa (18 mm), C. albicans (19 mm), and Aspergillus niger (15 mm). Results also revealed that CA film with 6% exhibited lower activity than film with 2% Cu-NPs. The morphological properties of CA/Cu-NPs films were characterized by scanning electron microscopy and transmission electron microscope in addition to X-ray diffraction. Low-loaded Cu-NPs showed homogenous distribution through CA matrix while, the high-loaded Cu-NPs were agglomerated through CA matrix. Thermal properties illustrated the enhancement of thermal stability of the film with increasing the loaded Cu-NPs.     

Flow field-flow fractionation with off-line electrothermal atomic absorption spectrometry for size characterization of silver nanoparticles

Flow field-flow fractionation (Fl-FFF) with off-line electrothermal atomic absorption spectrometry (ETAAS) detection was developed and employed for particle size characterization of Ag NPs stabilized by citrate, pectin, and alginate. Citrate stabilized-Ag NPs were prepared from sodium borohydride reduction of silver nitrate. Sodium citrate was used as the capping agent to stabilize Ag NPs and prevent the aggregation process. Pectin stabilized- and alginate stabilized-Ag NPs were prepared from ascorbic acid reduction of silver nitrate. Pectin and alginate were used as the capping agent for pectin stabilized- and alginate stabilized-Ag NPs, respectively. Three types of Ag NPs were characterized by using FlFFF, zeta potentiometer, and TEM technique. The mean particle sizes of Ag NPs as characterized by FlFFF were 9 nm, 19 nm, and 45 nm for citrate stabilized-, pectin stabilized-, and alginate stabilized-Ag NPs, respectively, in deionized water. Further, FlFFF with ETAAS detection was employed to observe the aggregation of Ag NPs of various types in environmental water in the absence and presence of humic acid. Citrate stabilized-Ag NPs underwent aggregation more rapid than the pectin stabilized- and alginate stabilized-Ag NPs as the latter two types were sterically stabilized. Further, humic acid could prolong the stability of Ag NPs in the environment.     

The immobilization of antineoplastic drug cyclophosphamide in calcium alginate

IR spectroscopy and scanning electron microscopy were used for the study of formation of calcium alginate particles. The synthesis was carried out in an aqueous medium via reaction between sodium alginate and calcium chloride. It was found that calcium alginate particles with a homogeneous and dense structure were formed at concentrations 2 wt % and 0.1 M of sodium alginate and calcium chloride, respectively. Formation of calcium alginate particles in the systems containing chitosan was accompanied by the emergence of an adsorption layer of chitosan on the particle surface. The thickness of this layer increased with the enhancement of chitosan concentration. The release kinetics of cyclophosphamide from calcium alginate particles in physiological solution in vitro was investigated. The results showed that such factors as elevated temperature at the drying of calcium alginate particles, the increase in the amount of guluronate in the initial sodium alginate, and thickening of the chitosan adsorbed layer led to a significant decrease in the release rate.     

NaOH浓度对Cu_2O结构及甲醛乙炔化性能的影响

以CuCl_2·2H_2O为铜源,NaOH为沉淀剂,L-抗坏血酸钠为还原剂,采用液相还原法制备了Cu_2O,并将其应用于甲醛乙炔化反应制1,4-丁炔二醇.借助傅里叶变换红外光谱(FT-IR)、拉曼光谱(Raman)、X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和H_2程序升温还原(H2-TPR)等手段研究了NaOH浓度对Cu_2O结构、性质及催化性能的影响.结果表明,调变NaOH浓度改变了Cu2O的结晶度与粒径,从而使Cu_2O表现出不同的炔化性能.低NaOH浓度时,Cu_2O结晶度低,粒径小,易被还原为非活性的金属Cu;高浓度时,Cu_2O结晶度过高,粒径大,难以转化为活性物种炔化亚铜,两者均造成催化剂活性较低.而中等浓度的NaOH使Cu_2O具有了适宜的结晶度与粒径大小,Cu_2O可高效转化为炔化亚铜活性物种,表现出最优的炔化性能.     

Leaching of Celestite in Sodium Hydroxide Solutions and Kinetic Modelling

In this study, the dissolution kinetics of celestite in solutions of sodium hydroxide was investigated by batch process. The results showed that the parameters which had the greatest effect on the dissolution of celestite in sodium hydroxide solutions were reaction temperature, the concentration of sodium hydroxide and stirring speed. It was determined that the dissolution rate increased with increased stirring speed, sodium hydroxide concentration, reaction time and temperature and decreased with increasing particle size and solid-liquid ratio. The leaching process fitted the shrinking core model with diffusion through the product layer model as the rate-determining step. The activation energy of the dissolution of celestite was calculated as 62.24?kJ/mol. A semi-empirical kinetic model was obtained for dissolution of celestite in sodium hydroxide solution.     

海藻酸酮膜表面的配位结构及催化MMA聚合的性能

将海藻酸钠(SA)与CuCl2.2H2反应得到一种配位聚合物海藻酸酮(Cu-An)。以ESR、电导率、IR和SPS方法对此配位聚合物进行表征,确定了组成与结构：同时研究了甲基丙烯酸甲酯(MMA)在该配位聚合物膜、HSO3^-和水体系催化引发作用下的聚合反应历程。结果表明,配位聚合物的中心离子Cu^2^+与两个海藻酸(An)链节单元上的两个羧羟基氧原子和两个离解氢原子的羧羟基氧原子以共价型配位,配位数为4.MMA在上述的催化引发体系中是按照自由基加聚反应历程进行聚合的,PMMA呈无规结构。Cu-An在催化引发体系中起着催化剂的配位催化作用。     

Biodistribution of colloidal gold nanoparticles after intravenous administration: effect of particle size

Purpose of the present research work was to evaluate the biological distribution of differently size gold nanoparticles (NP) up on intravenous administration in mice. Another objective was to study effect of particle size on biological distribution of gold NP to enable their diverse applications in nanotechnology. Gold NP of different particle sizes, mainly 15, 50, 100 and 200nm, were synthesized by modifying citrate ion concentration. Synthesized gold nanoparticles were characterized by SEM and their size distribution was studied by particle size analyzer. Gold NP was suspended in sodium alginate solution (0.5%, w/v) and administered to mice (1g/kg, intravenously) [n=3]. After 24h of administration of gold NP, blood was collected under light ether anesthesia, mice were sacrificed by cervical dislocation and various tissues/organs were removed. The tissues were then washed with saline, homogenized and lysed with aqua regia. The determination of gold in samples was carried out quantitatively by inductively coupled plasma mass spectrometry (ICP-MS). SEM study revealed spherical morphology of gold NP with narrow particle size distribution. Biodistribution study revealed gold NPs of all sizes were mainly accumulated in organs like liver, lung and spleen. The accumulation of gold NP in various tissues was found to be depending on particle size. 15nm gold NP revealed higher amount of gold and number of particles in all the tissues including blood, liver, lung, spleen, kidney, brain, heart, stomach. Interestingly, 15 and 50nm gold NP were able to pass blood-brain barrier as evident from gold concentration in brain. Two-hundred nanometers gold NP showed very minute presence in organs including blood, brain, stomach and pancreas. The results revealed that tissue distribution of gold nanoparticles is size-dependent with the smallest 15nm nanoparticles showing the most widespread organ distribution.     

胶体铜催化丙烯腈水合的高选择性及其活性中心结构的研究

研究了胶体铜催化丙烯腈水合制丙烯酰胺的高选择性与活性中心结构的关系. 在聚乙烯吡咯烷酮(PVP)保护下, 用肼和氢氧化钠混合液还原CuCl2制得胶体铜, 用其催化丙烯腈水合反应, 选择性达到100％, 产生高选择性的原因如下: (1) 胶体铜的活性中心不是胶粒表面的点缺陷, 而是胶体铜颗粒表面的位错端点. (2) 由于胶体铜具有高硬度和高强度的力学特性, 保证了活性中心结构的稳定性; 胶体铜颗粒的平均粒径(45 nm)超过晶粒的特征长度, 进一步保证了活性中心的稳定性.     

Study of the drying behavior of model latex blends during film formation: influence of carboxyl groups

Latex blending is a strategy used to eliminate volatile organic compounds from latex coatings formulations. This paper focuses on the study of the drying kinetics of model hard/soft latex blends and the influence of the presence of carboxyl groups on these particles as well as the extent of neutralization of the carboxyl groups with different bases. The model latex blend was comprised of clean, well‐defined polystyrene hard and poly(n‐butyl methacrylate‐co‐n‐butyl acrylate) soft latex particles with monodisperse particle sizes, homogeneous copolymer composition, and independent control of particle size and carboxyl group content. Drying models are discussed. It was found that the presence of carboxyl groups in the latex particles retarded the drying rate of the model latex blends. When the carboxyl groups present in the latex blends with low carboxyl group coverage on polystyrene particles were neutralized by using ammonium hydroxide or sodium hydroxide, the drying rate increased. When the carboxyl groups present in the latex blends with a high carboxyl group coverage on polystyrene particles were neutralized by sodium hydroxide, potassium hydroxide, or cesium hydroxide, the drying rate first decreased and then increased as the extent of the neutralization increased. However, the neutralization of these carboxyl groups with ammonium hydroxide increased the drying rate of the latex blends within a broad range of neutralization conditions (from 0 to 100%). A cluster model was proposed to explain these phenomena.     

CuPc(COOH)8-SA/CuTAPc-CS双极膜的制备及表征

分别用八羧基铜酞菁[CuPc(COOH)₈]和四氨基铜酞菁(CuTAPc)改性海藻酸钠(SA)阳膜层和壳聚糖(CS)阴膜层, 制备了CuPc(COOH)₈-SA/CuTAPc-CS双极膜. 实验结果表明, 经八羧基铜酞菁和四氨基铜酞菁改性后, 促进了双极膜中间层水的解离, 增大了阳离子交换膜层和阴离子交换膜层的离子交换容量及H⁺和OH^-的透过率. 与Fe³⁺改性的Fe-SA/mCS双极膜相比, CuPc(COOH)₈-SA/CuTAPc-CS双极膜的阻抗、电阻压降(即IR降)和溶胀度降低. 当电流密度高达120 mA/cm²时, CuPc(COOH)₈-SA/CuTAPc-CS双极膜的IR降仅为0.9 V.     

7种生物碱在不同粒径卷烟主流烟气气溶胶中的分布研究

建立了烟气气溶胶中7种生物碱的气相色谱-质谱(GC-MS)测定方法,并采用电子低压撞击器(ELPI)分12级捕集烟气气溶胶粒相物,研究了卷烟主流烟气气溶胶中7种生物碱含量和浓度的粒径分布。捕集的气溶胶样品加入氢氧化钠溶液和二氯甲烷进行碱法提取,提取液经DB-5MS弹性毛细管柱分离,选择离子监测模式测定,内标法定量。结果表明:该法检测主流烟气气溶胶中7种生物碱的相对标准偏差(RSD)为2.1%~6.4%,检出限为0.39~14.84 ng/cig,加标回收率为85.5%~124.8%。7种生物碱主要分布于0.144~0.722μm的中等粒径气溶胶粒相物中,在粒径0.431μm的粒相物中含量最高,与捕集的粒相物质量分布一致。7种生物碱在不同粒径气溶胶粒相物中的浓度基本趋于一致,其浓度随气溶胶粒径的分布无特异性。     

The effect of particle size and metal contents on arsenic distribution in coal-fired fly ash

Fly ash samples were collected from a Chinese power station and divided according to particle size. The solid fly ash samples were digested according to ASTM methods. The arsenic contents of samples with different particle sizes were analyzed using atomic fluorescence spectroscopy after digestion. Other metals were analyzed using inductively coupled plasma-atomic emission spectrometer after digestion, and the carbon content was analyzed by a CHN elemental analyzer. The results show that the arsenic components are enriched in smaller fly ash particles. The arsenic contents have a positive relationship with calcium, magnesium, and iron contents, which indicate that stable compounds are formed between these components. Thermogravimetric experiments of fly ash samples with different particle sizes were conducted, and the results indicate the combination of calcium hydroxide with arsenic form stable compounds.     

纳米氧化锌粒子分散性对其吸收光谱的影响

在异丙醇中用氢氧化钠分别与醋酸锌及溴化锌反应制备了纳米氧化锌粒子. 分别用高分辨率电子显微镜及原位紫外吸收光谱测定了粒子大小及分布. 实验结果表明, 粒子的增大服从LSW (Lifshitz-Slyozov-Wagner)模型, 即粒子体积随老化时间线性增大；但粒子的分布不符合LSW模型, 这与他人的研究结果不一致. 用计算机数值模拟确定了纳米氧化锌分布函数对其紫外吸收光谱的影响, 发现在紫外吸收边附近光谱发生弯曲, 且随粒子分布标准方差(SD)的增大, 弯曲更显著, 引起紫外吸收光谱红移, 这将导致用吸收边计算氧化锌粒子大小时产生正误差. 就单分散(SD/γ<5%, γ是粒子的平均半径)纳米氧化锌而言, 这种正误差仅为2%, 但当粒子分布的SD/γ达到15%时, 所产生的正误差可高达15.1%.     

海藻酸-磷脂微囊复合水凝胶的制备、表征及毒理学分析

采用薄膜分散法合成磷脂微囊,根据胶粒的双电层理论,通过在微囊中加入氯化锰、氯化钙和氯化镁电解质溶液,使微囊处于相对稳定的状态.研究发现加入氯化锰和氯化钙溶液,微囊胶体的粒径没有明显的变化,但加入一定浓度氯化镁溶液,其粒径明显变大.为了进一步增加磷脂微囊稳定性,将氯化锰、氯化钙、氯化镁磷脂微囊胶体分别与海藻酸钠(SA)溶液混合.结果表明,氯化镁与SA几乎不能形成水凝胶,氯化钙与SA形成水凝胶能力强于氯化锰.微囊胶体溶液中的磷脂酰丝氨酸(PS)可以与Ca~(2+)和Mg~(2+)键合形成PS-Ca~(2+)和PS-Mg~(2+),但不能与Mn~(2+)键合形成PS-Mn~(2+).对氯化钙磷脂微囊与海藻酸钠合成的复合水凝胶的形貌、溶胀率及细胞毒性进行了表征,结果表明,氯化钙与SA形成的水凝胶可以捕获胶体中磷脂微囊,且形貌规整,结构稳定,无细胞毒性.     

Solvothermal syntheses of nano- and micro-sized ZnO powders with a controllable morphology

Zinc oxide powders with different morphologies and grain sizes were synthesized using solvothermal methods from ethanolic zinc acetate solutions in the presence of lithium hydroxide. The influence of the temperature and the time of the reaction, as well as the pH value of the starting solution, on the ZnO particle size and morphology were examined. It was found that an increase in the pH value from 8 to 12 results in a significant decrease in the mean particle size. Also, the particles?? morphology can be changed from hexagonal plates and prisms to rods by controlling the reaction time and the temperature. The crystallization mechanism is discussed, based on established correlations such as the particle size/shape versus the reaction parameters. Dissolution/recrystallisation is the most probable growth mechanism responsible for the ZnO particles?? morphology obtained in the solvothermal (hydrothermal) reactions with a basic solution. The planar structure of the zinc-hydroxy-acetate molecule plays the main role in growing the structures during the sovothermal reactions with a slightly acid solution.