磁性壳聚糖复合微球的制备及其Cu~(2+)吸附性能

以球磨后的粉煤灰磁珠(MS)颗粒为磁核,通过溶胶凝胶法和反相微乳液法依次包覆SiO_2和壳聚糖(CS),制备了MS@SiO_2@CS磁性微球。利用扫描电镜及能量色散谱仪、热重分析仪、红外光谱仪、X射线衍射仪、振动样品磁强计对所得样品的结构和磁性进行了系统表征。结果表明,磁珠颗粒表面实现了逐层包覆,较均匀的分散于壳聚糖基体中,MS@SiO_2@CS微球的比饱和磁化强度可达7.04 emu·g~(-1)。Cu~(2+)离子吸附实验表明,所得磁性壳聚糖微球对Cu~(2+)具有良好的吸附能力,最大吸附量可达11.08 mg·g~(-1);而且可通过磁选法高效固液分离。吸附动力学研究表明,MS@SiO_2@CS微球对Cu~(2+)离子的吸附符合准二级动力学模型,以化学吸附为主。     

氨基化修饰介孔Fe3O4@SiO2@mSiO2磁性核壳复合微球的可控制备及吸附性能

以水热法制备的高磁饱和强度Fe₃O₄纳米颗粒为核,正硅酸乙酯（TEOS）为前驱体,采用改进的Stöber法,制备介孔SiO₂包覆Fe₃O₄磁性核壳复合微球。利用XRD、SEM、TEM、N₂吸-脱附、FTIR和VSM对制备样品的物相结构、形貌和磁性能进行了测试表征。研究结果表明,制备的复合材料呈球形,粒径分布均一,材料的比表面积和磁饱和强度分别为413 m²·g^-1和68.93 emu·g^-1。研究了TEOS的添加量对复合微球形貌的影响,随着TEOS添加量的增加,SiO₂壳层增厚,复合粒子形貌均匀,饱和磁化强度有所下降,仍具有良好的超顺磁性。在此基础上,通过接枝法在复合微球的表面接枝-NH₂,制备了一种新型磁性纳米吸附剂（Fe₃O₄@SiO₂@mSiO₂-NH₂）,进而研究了其对水中重金属离子Cr（Ⅳ）的吸附性能。通过动力学拟合,Fe₃O₄@SiO₂@mSiO₂-NH₂对Cr（Ⅳ）的吸附过程是准二级动力学模型占主导地位。探究了该材料对Cr（Ⅳ）的吸附过程和吸附机理。结果表明,其吸附机理及吸附容量与Cr（Ⅳ）的离子形态及-NH₂有关,并通过吸附剂与吸附质之间的电子共用或静电吸附实现。     

双功能化磁性纳米修复剂对多重金属的快速、高效钝化行为

采用“一锅法”制备了四氧化三铁/半胱氨酸（Fe₃O₄/Cys）磁性纳米微球,随后对Fe₃O₄/Cys进行亚氨基二乙酸（IDA）修饰得到Fe₃O₄/Cys/IDA磁性双功能化纳米微球。研究发现Fe₃O₄/Cys中的L-Cys是通过—SH基团接枝到Fe₃O₄表面的,随后IDA分子中的羧基与Fe₃O₄/Cys中的—NH₂形成酰胺键,最终形成多支链多羧基的Fe₃O₄/Cys/IDA磁性纳米修复剂。基于修复剂表面短支链-长支链交替的多羧基结构,实现了羧基基团的高密度接枝。同时,Fe₃O₄/Cys/IDA磁性纳米微球对Pb²⁺、Cd²⁺、Cu²⁺、Co²⁺、Ni²⁺、Zn²⁺为专性吸附,而对Hg²⁺属于非专性吸附,且吸附重金属后得到的钝化产物均表现了良好的稳定性。另外,Fe₃O₄/Cys/IDA对重金属离子的吸附符合Langmuir模型,属于单层均相吸附,其吸附过程符合准二级动力学模型,最大吸附量为49.05 mg·g^-1。     

用于检测重金属离子的磁性荧光复合微球

采用静电逐层自组装的方法,首先将PSS和PAH聚电解质交替沉积在CaCO₃中空微球表面,然后将Fe₃O₄磁性纳米粒子与CdSe量子点负载在中空微球表面不同的聚电解质层中,制备出具有磁性和荧光双重功能的复合微球,并将其作为荧光离子探针,研究了其对Cu²⁺和Pb²⁺离子检测的灵敏度、选择性及可行性。结果表明,复合微球显示出良好的磁性和荧光性能,对Cu²⁺和Pb²⁺离子的检测具有较高的灵敏度和选择性。尤为重要的是,可通过磁分离的方法将微球快速地从待测液中回收,从而能够避免量子点对环境造成的二次污染。     

锌镍铝水滑石微球的制备及吸附性能

以Zn（NO₃）₂·6H₂O、Ni（NO₃）₂·6H₂O、Al（NO₃）₃·9H₂O和尿素为原料,采用一步水热法制备分散性良好的三元锌镍铝水滑石（ZnNiAl-LDHs）微球。通过X射线衍射（XRD）、傅里叶转换红外光谱（FTIR）、场发射扫描电镜（FESEM）、透射电镜（TEM）和氮气吸附-脱附等测试手段对样品的结构和形貌进行表征,并比较ZnNiAl-LDHs和ZnAl-LDHs对甲基橙（MO）的吸附性能。结果表明,ZnNiAl-LDHs是由纳米片组成、具有3D结构的微球,粒径为1~2.5 μm,比表面积为156 m²·g^-1,远大于ZnAl-LDHs的比表面积38 m²·g^-1;ZnNiAl-LDHs和ZnAl-LDHs对甲基橙的饱和吸附量分别为329.60和143.47 mg·g^-1,ZnNiAl-LDHs表现出更强的吸附能力,其吸附等温线和吸附动力学分别符合Langmuir等温线模型和准二级动力学模型。     

pH值调节方式对LAB辅助合成纳米Cu2O微球的影响与组装机理

以Cu(Ac)₂为原料,两性表面活性剂月桂酰胺丙基甜菜碱(LAB)为模板,采用两种不同的调节pH值方式制备了Cu₂O纳米材料.表征结果表明两种调节pH值方式均可获得Cu₂O纳米微球,并都呈立方晶相,而且样品的红外吸收峰、固体紫外吸收峰都不同程度的发生了蓝移;第一种Cu₂O纳米微球由针状纳米粒子积聚而成,针状纳米粒子间空隙孔径主要分布在25~50 nm之间,比表面积为22 m²·g^-1,禁带宽度为2.15 eV;第二种Cu₂O纳米微球由小的纳米球状体堆积而成,球状体间孔道直径集中在25~50 nm和50~125 nm两个区域,比表面积为9 m²·g^-1,禁带宽度为2.46 eV.两种不同的调节pH值方式获得的Cu₂O纳米微球,其反应历程和自组装机理存在不同.     

ZrO2包覆的层状富锂正极材料0.6Li[Li1/3Mn2/3]O2·0.4LiNi5/12Mn5/12Co1/6O2的电化学性能

采用喷雾干燥法合成了富锂层状氧化物正极材料0.6Li[Li_1/3Mn_2/3]O₂·0.4LiNi_5/12Mn_5/12Co_1/6O₂(简称LNMCO),并使用Zr (CH₃COO)₄进行ZrO₂的包覆改性。TEM测试结果显示纳米级的ZrO₂颗粒附着在LNMCO的表面。包覆质量分数为1.5%的ZrO₂包覆样品的首圈库伦效率和放电比容量有着显著提升,在室温下其首圈库伦效率和放电比容量(电流密度：20 mA·g^-1,电压：2.0~4.8 V)分别为87.2%,279.3 mAh·g^-1,而原样则为75.1%,224.1 mAh·g^-1,循环100圈之后,1.5% ZrO₂包覆样品的放电比容量为248.3 mAh·g^-1,容量保持率为88.9%,高于原样的195.9 mAh·g^-1和87.4%。     

锂离子电池负极Si@LiAlO2纳米复合材料的简易制备

采用溶剂热法和煅烧法制备了LiAlO₂包覆Si纳米颗粒（Si@LiAlO₂）的复合材料。Si@LiAlO₂纳米颗粒具有开口和通道的树枝状结构。电化学性能测试表明,其在100 mA·g^-1电流密度下循环100次后可逆容量为364.1 mAh·g^-1。纳米复合材料的树枝状结构使其具有优越的循环性能。在树枝状结构中,纳米尺度的硅颗粒缩短了锂离子的传输路径,LiAlO₂包覆层、孔隙和开口缓冲了硅在充放电过程中的体积变化。     

银纳米颗粒掺杂的活性微孔炭球：一种高效吸附/催化去除刚果红的双功能材料

以载银纳米颗粒壳聚糖溶液为前驱体,联合喷雾干燥法、高温碳化法和KOH活化法制备出银纳米颗粒掺杂的活性微孔炭球(Ag/AMCSs)。基于一系列表征和性能研究发现,银纳米颗粒均匀分布于Ag/AMCSs结构中,Ag/AMCSs不仅表现出优异的染料吸附性能,而且可以有效催化NaBH₄还原刚果红(CR)的反应。此外,通过研究pH值、接触时间和染料初始浓度对Ag/AMCSs吸附性能的影响,发现Ag/AMCSs对CR的吸附过程符合准二级动力学模型和Langmuir模型,最大吸附量(q_e)可达445mg·g^-1。Ag/AMCSs催化NaBH₄还原CR,反应速率常数k可达0.311min^-1,5次循环利用后,染料催化转化率仍可高达95%。     

双层SiO2包覆Fe3O4复合材料的制备及其染料吸附性能

采用改进的Stober法合成了多孔结构的双层SiO₂包覆Fe₃O₄复合材料,利用TEM、XRD、VSM和氮吸附-脱附实验对其结构与性能进行分析,进而研究其对染料的吸附性能。研究结果表明,双层SiO₂包覆Fe₃O₄复合材料的比表面积和磁饱和强度分别为308 m²·g^-1和45.5 emu·g^-1;当罗丹明B的初始浓度从25 mg·L^-1提高到250 mg·L^-1时,复合材料对其饱和吸附量从24.0 mg·g^-1增大到112.4 mg·g^-1,而亚甲基蓝的初始浓度从25 mg·L^-1提高到500 mg·L^-1时,对其饱和吸附量从22.0 mg·g^-1增大到235.1 mg·g^-1;随着溶液pH值增大,复合材料对罗丹明B的饱和吸附量增加,而对亚甲基蓝的饱和吸附量变化不明显;温度在20~40 ℃范围内复合材料的吸附量较大。     

磁性壳聚糖/Fe3O4/氧化石墨烯吸附剂的制备及其多染料吸附性能

为了提高壳聚糖的多染料吸附性能并使其便于固液分离,采用共沉淀法制备了壳聚糖、磁铁矿纳米颗粒、氧化石墨烯复合磁性吸附剂(CS/Fe₃O₄/GO)。系统的结构表征显示,CS包覆的Fe₃O₄磁性纳米颗粒均匀地分布在GO的表面。CS/Fe₃O₄/GO具有高达42.5 emu·g^-1的室温铁磁性,因此可在外加磁场中实现高效固液分离。研究表明,CS/Fe₃O₄/GO对亚甲基蓝(MB)、甲基橙(MO)和刚果红(CR)等多种染料具有良好的吸附性能,溶液的pH、初始浓度和吸附时间对其多染料吸附性能具有显著影响。在最佳条件下,CS/Fe₃O₄/GO对MB、MO和CR的吸附量分别达到210.6、258.6和308.9 mg·g^-1。CS/Fe₃O₄/GO具有优异的循环利用性能,经5次循环后仍能保留90%以上的原始吸附量。采用吸附等温线和吸附动力学对CS/Fe₃O₄/GO的多染料吸附性能进行了拟合分析,并详细讨论了其吸附机理。     

磁性壳聚糖/Fe3O4/氧化石墨烯吸附剂的制备及其多染料吸附性能

为了提高壳聚糖的多染料吸附性能并使其便于固液分离,采用共沉淀法制备了壳聚糖、磁铁矿纳米颗粒、氧化石墨烯复合磁性吸附剂(CS/Fe₃O₄/GO)。系统的结构表征显示,CS包覆的Fe₃O₄磁性纳米颗粒均匀地分布在GO的表面。CS/Fe₃O₄/GO具有高达42.5 emu·g-1的室温铁磁性,因此可在外加磁场中实现高效固液分离。研究表明,CS/Fe₃O₄/GO对亚甲基蓝(MB)、甲基橙(MO)和刚果红(CR)等多种染料具有良好的吸附性能,溶液的pH、初始浓度和吸附时间对其多染料吸附性能具有显著影响。在最佳条件下,CS/Fe₃O₄/GO对MB、MO和CR的吸附量分别达到210.6、258.6和308.9 mg·g-1。CS/Fe₃O₄/GO具有优异的循环利用性能,经5次循环后仍能保留90%以上的原始吸附量。采用吸附等温线和吸附动力学对...     

Magnetic Silica‐Coated Sub‐Microspheres with Immobilized Metal Ions for the Selective Removal of Bovine Hemoglobin from Bovine Blood

Magnetic silica‐coated magnetite (Fe₃O₄) sub‐microspheres with immobilized metal‐affinity ligands are prepared for protein adsorption. First, magnetite sub‐microspheres were synthesized by a hydrothermal method. Then silica was coated on the surface of Fe₃O₄ particles using a sol–gel method to obtain magnetic silica sub‐microspheres with core‐shell morphology. Next, the trichloro(4‐chloromethylphenyl) silane was immobilized on them, reacted with iminodiacetic acid (IDA), and charged with Cu²⁺. The obtained magnetic silica sub‐microspheres with immobilized Cu²⁺ were applied for the absorption of bovine hemoglobin (BHb) and the removal of BHb from bovine blood. The size, morphology, and magnetic properties of the resulting magnetic micro(nano) spheres were investigated by using scanning microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), and a vibrating sample magnetometer (VSM). The measurements showed that the magnetic sub‐microspheres are spherical in shape, very uniform in size with a core‐shell, and are almost superparamagnetic. The saturation magnetization of silica‐coated magnetite (Fe₃O₄) sub‐microspheres reached about 33 emu g^?1. Protein adsorption results showed that the sub‐microspheres had a high adsorption capacity for BHb (418.6 mg g^?1), low nonspecific adsorption, and good removal of BHb from bovine blood. This opens a novel route for future applications in removing abundant proteins in proteomic analysis.     

Layers of <Emphasis Type="Italic">x</Emphasis>CuS-SiO<Subscript>2</Subscript>·<Emphasis Type="Italic">n</Emphasis>H<Subscript>2</Subscript>O nanocomposite,synthesized by the layer-by-layer technique

For the first time conditions were determined for the synthesis of Cu _x SiO_2+x ·nH₂O nanostructured layers by consecutive adsorption of copper ammine cations and adagulation of colloidal SiO₂ particles and also for the synthesis of xCuS-SiO₂·nH₂O nanocomposite layers by consecutive surface adsorption of copper cations and HS^? anions. These layers were studied by means of UV and visible transmission spectroscopy, X-ray spectral microanalysis, and scanning electron microscopy. Schemes of the surface reactions were constructed on the basis of this experimental material.     

Preparation and adsorption properties of crosslinked polystyrene-supported low-generation diethanolamine-typed dendrimer for metal ions

Two novel chelating resins, polystyrene supported G1.0 diethanolamine-typed dendrimer (PS-DEA) and G2.0 diethanolamine-typed dendrimer (PS-(DEA)₂), were prepared by anchoring low-generations diethanolamine-typed dendrimer into crosslinked polystyrene in this paper. Fourier transform-infrared spectra (FTIR), scanning electron microscopy (SEM) and elemental analysis were employed to character their structures. The results of adsorption for metal ions showed that the resins had good adsorption capacities for Cu²⁺, Ag⁺ and Hg²⁺, especially PS-DEA for Cu²⁺. The adsorption kinetics and adsorption isotherms of PS-DEA for Cu²⁺ and PS-(DEA)₂ for Hg²⁺ were studied. The results showed that the adsorption kinetics of the two resins can be modeled by pseudo second-order rate equation wonderfully and Langmuir and Freundlich equations could well interpret the adsorption of PS-(DEA)₂ for Hg²⁺ and PS-DEA for Cu²⁺, respectively. The adsorption mechanism of the resins for Cu²⁺ was confirmed by X-ray photoelectron spectroscopy (XPS).     

Magnetically recyclable nano copper/chitosan in O‐arylation of phenols with aryl halides

Interaction of chitosan (CS) with Fe₃O₄, followed by embedding Cu nanoparticles (NPs) on the magnetic surface through adsorption of Cu²⁺, and its reduction to Cu^o via NaBH₄, offers a reusable efficient catalyst (Fe₃O₄/CS‐Cu NPs) that is employed in cross‐coupling reactions of aryl halides with phenols, which affords the corresponding diaryl ethers, with good to excellent yields. The catalyst is completely recoverable from the reaction mixture by using an external magnet. It can be reused four times, without significant loss in its catalytic activity.     

粉煤灰磁性吸附剂的制备及磷吸附机理

通过化学沉淀法制备了CMS@La_2O_3磁性磷吸附剂。结构及磁性表征显示,氧化镧较均匀的包覆在粉煤灰磁珠表面;样品的比磁化强度达20.35 emu·g~(-1),可实现高效磁分离。利用钼酸铵分光光度法对所得磁性吸附剂的磷吸附性能进行了试验研究。研究表明,其最高磷比饱和吸附量可达19.50 mg·g~(-1),吸附时间、pH值、共存阴离子等因素对磷吸附效果均具有显著影响。吸附动力学拟合表明,CMS@La_2O_3对含磷离子的吸附符合准二级动力学方程,以化学吸附为主,磁性吸附剂对含磷离子的吸附反应过程可由La_2O_3表面羟基化-离子交换模型解释。吸附磷后的CMS@La_2O_3吸附剂经处理后可多次循环使用。     

Preparation of core–shell structure Fe3O4@SiO2 superparamagnetic microspheres immoblized with iminodiacetic acid as immobilized metal ion affinity adsorbents for His‐tag protein purification

The core–shell structure Fe₃O₄/SiO₂ magnetic microspheres were prepared by a sol–gel method, and immobiled with iminodiacetic acid (IDA) as metal ion affinity ligands for protein adsorption. The size, morphology, magnetic properties and surface modification of magnetic silica nanospheres were characterized by various modern analytical instruments. It was shown that the magnetic silica nanospheres exhibited superparamagnetism with saturation magnetization values of up to 58.1 emu/g. Three divalent metal ions, Cu²⁺, Ni²⁺ and Zn²⁺, were chelated on the Fe₃O₄@SiO₂–IDA magnetic microspheres to adsorb lysozyme. The results indicated that Ni²⁺‐chelating magnetic microspheres had the maximum adsorption capacity for lysozyme of 51.0 mg/g, adsorption equilibrium could be achieved within 60 min and the adsorbed protein could be easily eluted. Furthermore, the synthesized Fe₃O₄@SiO₂–IDA–Ni²⁺ magnetic microspheres were successfully applied for selective enrichment lysozyme from egg white and His‐tag recombinant Homer 1a from the inclusion extraction expressed in Escherichia coli. The result indicated that the magnetic microspheres showed unique characteristics of high selective separation behavior of protein mixture, low nonspecific adsorption, and easy handling. This demonstrates that the magnetic silica microspheres can be used efficiently in protein separation or purification and show great potential in the pretreatment of the biological sample. Copyright © 2015 John Wiley & Sons, Ltd.