A luminescent and mesoporous core-shell structured Gd2O3 : Eu(3+)@nSiO2@mSiO2 nanocomposite as a drug carrier

In this paper, Gd(2)O(3) : Eu(3+) nanospheres have been encapsulated with nonporous silica and further layer of ordered mesoporous silica through a simple sol-gel process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N(2) adsorption/desorption, photoluminescence (PL) spectra, and kinetic decay were used to characterize the sample. The results indicate that the nanocomposite with general 50 nm shell thickness and 270 nm core size shows typical ordered mesoporous characteristics (2.4 nm) and has spherical morphology with a smooth surface and narrow size distribution. Additionally, the obtained inorganic nanocomposite shows the characteristic emission of Eu(3+) ((5)D(0)→(7)F(1-4)) even after the loading of drug molecules. The biocompatibility test on L929 fibroblast cells using MTT assay reveals low cytotoxicity of the system. Most importantly, the nanocomposite can be used as an effective drug delivery carrier. A typical anticancer drug, doxorubicin hydrochloride (DOX), was used for drug loading, and the DOX release, cytotoxicity, uptake behavior and therapeutic effects were examined. It was found that DOX is shuttled into the cell by the nanocomposite and released inside cells after endocytosis and that the DOX-loaded nanocomposite exhibited greater cytotoxicity than free DOX. These results indicate that core-shell structured Gd(2)O(3) : Eu(3+)@nSiO(2)@mSiO(2) nanocomposite has potential for drug loading and delivery into cancer cells to induce cell death.     

Synthesis of a multinanoparticle-embedded core/mesoporous silica shell structure as a durable heterogeneous catalyst

A multi-nanoparticle-embedded amorphous aluminum/magnesium oxides (AAMO) core/mesoporous silica (mSiO(2)) shell structure has been successfully synthesized by calcining the presynthesized catalyst precursor-containing layered double hydroxide (LDH) core/mesoporous silica shell composite. The well-dispersed catalytic nanoparticles were fixed at the interface between AAMO core and mesoporous SiO(2) shell, i.e., at the inner pore mouths of the mesoporous SiO(2) shell, which could effectively prevent nanoparticles from growth and/or aggregation with each other and in the meantime allow efficient access of reactants to the catalytic NPs. The final core/shell composite was found to be an efficient and highly recyclable heterogeneous catalyst.     

Preparation of magnetic core mesoporous shell microspheres with C18-modified interior pore-walls for fast extraction and analysis of phthalates in water samples

In this study, core-shell magnetic mesoporous microspheres with C18-functionalized interior pore-walls were synthesized through coating Fe(3)O(4) microspheres with a mesoporous inorganic-organic hybrid layer with a n-octadecyltriethoxysilane (C18TES) and tetraethyl orthosilicate (TEOS) as the silica source and cetyltrimethylammonia bromide (CTAB) as a template. The obtained C18-functionalized Fe(3)O(4)@mSiO(2) microspheres possess numerous C18 groups anchored in the interior pore-walls, large surface area (274.7 m(2)/g, high magnetization (40.8 emu/g) and superparamagnetism, uniform mesopores (4.1 nm), which makes them ideal absorbents for simple, fast, and efficient extraction and enrichment of hydrophobic organic compounds in water samples. Several kinds of phthalates were used as the model hydrophobic organic compounds to systematically evaluate the performance of the C18-functionalized Fe(3)O(4)@mSiO(2) microspheres in extracting hydrophobic molecules by using a gas chromatography-mass spectrometry. Various parameters, including eluting solvent, the amounts of absorbents, extraction time and elution time were optimized. Hydrophobic extraction was performed in the interior pore of magnetic mesoporous microspheres, and the materials had the anti-interference ability to macromolecular proteins, which was also investigated in the work. Under the optimized conditions, C18-functionalized Fe(3)O(4)@mSiO(2) microspheres were successfully used to analyze the real water samples. The results indicated that this novel method was fast, convenient and efficient for the target compounds and could avoid being interfered by macromolecules.     

Photochemistry catalyzed by copolymer-templated mesoporous SiO2: Decomposition of methanol and formic acid

Photochemical reactions of methanol and formic acid on L64 copolymer-templated mesoporous SiO2 have been investigated by Fourier transform infrared spectroscopy. Although SiO2 has been generally recognized to be photochemically inert, the reaction pathways HCOOH(a), HCOO(a)/SiO2 --> CO(2(g)) and CH3OH(a), CH3O(a)/SiO2 --> CH2O(a) --> HCOO(a) --> CO(2(g)) are demonstrated. The photons used in this study are unable to promote the SiO2 valance band electrons to the conduction band. Therefore photoholes take no part in these reactions. Mechanisms involving charge transfer and the surface species possible to initiate the photooxidation on mesoporous SiO2 under irradiation are discussed. For comparison purposes, parallel studies are also conducted for nonporous SiO2 to show the effect of porosity of SiO2 on the reactivity.     

Regenerable Fe-Mn-ZnO/SiO2 sorbents for room temperature removal of H2S from fuel reformates: performance, active sites, Operando studies

Fe- and Mn-promoted H(2)S sorbents Fe(x)-Mn(y)-Zn(1-x-y)O/SiO(2) (x, y = 0, 0.025) for desulfurization of model fuel reformates at room temperature were prepared, tested and characterized. Sulfur uptake capacity at 25 °C significantly exceeds that of both commercial unsupported ZnO sorbents and un-promoted supported ZnO/SiO(2) sorbents. Sulfur capacity and breakthrough characteristics remain satisfactory after multiple (～10) cycles of adsorption/regeneration, with regeneration performed by a simple and robust heating in air. XRD shows that both "calcined" and "spent" sorbents contain nano-dispersed ZnO, and XPS confirms conversion of ZnO to ZnS. "Calcined" sorbent contains Fe(3+) and Mn(3+) that are reduced to Mn(2+) upon reaction with H(2)S, but not with H(2). Operando ESR is used for the first time to study dynamics of reduction of Mn(3+) promoter sites simultaneously with measuring sulfidation dynamics of the Fe(x)-Mn(y)-Zn(1-x-y)O/SiO(2) sorbent. Fe cations are believed to occupy the surface of supported ZnO nanocrystallites, while Mn cations are distributed within ZnO.     

Sorption of the antibiotic ofloxacin to mesoporous and nonporous alumina and silica

Mesoporous and nonporous SiO(2) and Al(2)O(3) adsorbents were reacted with the fluoroquinolone carboxylic acid ofloxacin over a range of pH values (2-10) and initial concentrations (0.03-8 mM) to investigate the effects of adsorbent type and intraparticle mesopores on adsorption/desorption. Maximum ofloxacin adsorption to SiO(2) surfaces occurs slightly below the pK(a2) (pH 8.28) of the antibiotic and sorption diminishes rapidly at pH>pK(a2). For Al(2)O(3), maximum sorption is observed at pH values slightly higher than the adsorbent's point of zero net charge (p.z.n.c.) and less than midway between the pK(a) values of ofloxacin. The effects of pH on adsorption and ATR-FTIR spectra suggest that the zwitterionic compound adsorbs to SiO(2) solids through the protonated N(4) in the piperazinyl group and, possibly, a cation bridge; whereas the antibiotic sorbs to Al(2)O(3) solids through the ketone and carboxylate functional groups via a ligand exchange mechanism. Sorption edge and isotherm experiments show that ofloxacin exhibits a higher affinity for mesoporous SiO(2) and nonporous Al(2)O(3), relative to their counterparts. It is hypothesized that decreased ofloxacin sorption to mesoporous Al(2)O(3) occurs due to electrostatic repulsion within pore confines. In contrast, it appears that the environment within SiO(2) mesopores promotes sorption by inducing formation of ofloxacin-Ca complexes, thus increasing electrostatic attraction to SiO(2) surfaces.     

Templated carbon nanofiber with mesoporosity and semiconductivity

We have newly fabricated a long one-dimensional (1D) mesoporous carbon nanofiber by using a mesoporous silica nanofiber template. The resulting mesoporous carbon nanofiber shows the unique mesoporous structure of circularly wound nanochannel alignment perpendicular to the long fiber axis and the high gas sorption property, which interestingly presents the p-type semiconducting behavior.     

更低温度下和重复再生时NiO/SiO2催化剂上甲苯完全氧化反应

采用原子层沉积法将NiO沉积到粒径约为100 mm、平均孔径为14 nm的中孔SiO2颗粒的壳层(壳层厚度11 nm)区域,并分别在450和600°C进行热处理。将制得的这两种Ni/SiO2样品用于催化甲苯分子吸附及其氧化为CO2的反应中。结果发现,在450°C热处理的样品在甲苯吸附及其随后氧化为CO2的反应中表现出更高的活性;当将该样品暴露在160°C甲苯蒸气中,然后加热到450°C时,排放出CO2,而几乎没有甲苯脱附出来。这表明该催化剂可用于在200°C以下操作的、用于消除建筑物内有味气体的设备中,且该催化剂可以在450°C下经过热处理得到再生。     

The effect of interfacial microstructure on the lipid oxidation stability of oil-in-water emulsions

Novel rattle-type magnetic mesoporous carbon spheres are successfully prepared using composite spheres with Fe(3)O(4) as core and mesoporous SiO(2) as shell plus solid SiO(2) as a middle layer as templates. These rattle-type spheres possess the magnetization strength of as high as 37.5 emu/g, high and tunable specific surface areas (382-512.6 m(2)/g) due to mesoporous carbon shells. This magnetic rattle-type structure and the readily accessible mesoporous shell are very favoring for the fast adsorption and release of guest objects triggered by external stimulus, for example, the spheres showed very good adsorptive property to dye.     

新型SiO2/SiO2核壳型固定相的制备与评价

采用层层自组装的方法,以微米多孔硅胶小球为核,将硅胶纳米粒子多层包覆,制备了核壳型SiO2/SiO2硅胶小球.透射电子显微镜表明这种硅胶小球具有明显的核壳结构,氮气吸附实验证明该硅胶小球是典型的介孔材料,具有良好的介孔结构和窄的孔径分布.将其作为基质制备碳十八键合核壳型SiO2/SiO2色谱固定相,该固定相的碳含量与未...     

Superparamagnetic high-magnetization microspheres with an Fe3O4@SiO2 core and perpendicularly aligned mesoporous SiO2 shell for removal of microcystins

Superparamagnetic microspheres with an Fe3O4@SiO2 core and a perpendicularly aligned mesoporous SiO2 shell were synthesized through a surfactant-templating sol-gel approach. The microspheres possess high magnetization (53.3 emu/g), high surface area (365 m2/g), large pore volume (0.29 cm3/g), and uniform mesopore (2.3 nm). By using the unique core-shell microspheres with accessible large pores and excellent magnetic property, a fast removal of microcystins with high efficiency (>95%) can be achieved.     

Silica-coated nanocomposites of magnetic nanoparticles and quantum dots

Quantum dots (QDs) and magnetic nanoparticles (MPs) are of interest for biological imaging, drug targeting, and bioconjugation because of their unique optoelectronic and magnetic properties, respectively. To provide for water solubility and biocompatibility, QDs and MPs were encapsulated within a silica shell using a reverse microemulsion synthesis. The resulting SiO2/MP-QD nanocomposite particles present a unique combination of magnetic and optical properties. Their nonporous silica shell allows them to be surface modified for bioconjugation in various biomedical applications.     

Hollow titania spheres with movable silica spheres inside

We demonstrate a flexible method for preparing hollow TiO2 nanospheres with movable silica nanoparticles inside (HTNMSNs). In this method, we used monodisperse silica--polystyrene core--shell nanospheres (SiO2-PS-CSNs) sulfonated as templates and prepared the composite shell consisting of TiO2 and sulfonated polystyrene (SPS) through adsorbing or depositing tetrabutyl titanate gel into the SPS shell. Finally the HTNMSNs were obtained after removal of all polymers in the composite nanospheres by dissolution or calcinations. We investigated the dependence of the morphologies of HTNMSNs on the thickness of PS shells and the size of SiO2 cores and prepared rare earth doped HTNMSNs by a sol-gel process.     

Preparation of SiO2@polystyrene@polypyrrole sandwich composites and hollow polypyrrole capsules with movable SiO2 spheres inside

In this paper, we describe a flexible method for preparing conducting building blocks: SiO2@polystyrene@polypyrrole sandwich multilayer composites and hollow polypyrrole (PPy) capsules with movable SiO2 spheres inside. First, SiO2@polystyrene (PS) core/shell composites were synthesized, and then SiO2@PS@PPy sandwich multilayer composites were prepared by chemical polymerization of pyrrole monomer on the surface of SiO2@PS composites. Furthermore, hollow polypyrrole capsules with movable SiO2 spheres inside were obtained after removal of the middle PS layer. The diameter of sandwich multilayer composites could easily be controlled by adjusting the dosage of pyrrole monomer. The conductivities of composites increased with the increase of PPy content. After the insulating PS layer was selectively etched, the conductivities of hollow capsules with movable SiO2 spheres inside were much higher than those of the corresponding sandwich multilayer composites.     

Multifunctional magnetic mesoporous silica nanocomposites with improved sensing performance and effective removal ability toward Hg(II)

In the present work, a multifunctional inorganic-organic hybrid nanomaterial (MMS-Py) was prepared by the immobilization of a pyrene-based receptor (Py) within the channels of magnetic mesoporous silica nanocomposites (MMS), and characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N(2) adsorption/desorption, superconducting quantum interference device, and photoluminescence spectra. This multifunctional nanomaterial exhibits superparamagnetic behavior, ordered mesoporous characteristics, and significantly improved fluorescence sensing properties that allow for highly sensitive and reproducible Hg(2+) detection. The fluorogenical responses of MMS-Py are stable over a broad pH range. A detection limit of 1.72 ppb is obtained, which is 2 orders of magnitude lower than that based on bulk mesoporous materials. Additionally, this nanomaterial shows high performance in convenient magnetic separability and efficient removal of Hg(2+). These results indicate that these multifunctional nanocomposites may find potential applications for simple detection and easy removal of Hg(2+) in biological, toxicological, and environmental areas.     

自下而上法制备金-介孔二氧化硅复合纳米管用作还原4-硝基苯酚的催化剂

采用自下而上方法制备了金-介孔二氧化硅复合纳米管,其中金纳米粒子作为催化剂嵌在介孔二氧化硅纳米管管壁内侧。金纳米颗粒的团聚、脱落和晶粒尺寸生长都可以被有效限制,而且催化剂负载量和尺寸大小均可实现简单控制。管壁中的介孔孔道、纳米管末端开口以及一维中空管道可以协同促进反应物扩散,从而提高4-硝基苯酚还原反应活性。循环实验证明这种复合纳米管催化剂具有良好的可重复使用性,而且在反应过程中未出现金纳米粒子脱落或团聚现象。     

Fabrication and chemical crosslinking of electrospun <Emphasis Type="Italic">trans</Emphasis>-polyisoprene nanofiber nonwoven

In this work, the optimal electrospinning conditions of trans-polyisoprene (TPI) solutions were evaluated nevertheless its lower glass transition temperature than the room temperature. Subsequently, chemical crosslinking of TPI nonwovens was firstly investigated by vulcanizing at high temperatures in the case of the persistence of nanofiber structure. For this purpose, curing agents of TPI were embedded in TPI nanofibers by co-electrospinning, and then a protect layer was coated on TPI nanofibers by filtering gelatin solution going through TPI nonwoven before the vulcanization at 140?160 °C. The results showed that the vulcanization of TPI fibrous nonwoven at high temperatures did not destroy the fiber morphology. Interestingly, TPI fibrous nonwovens after vulcanization showed excellent mechanical properties (~17 MPa of tensile strength) that could be comparable to or even higher than that of some bulk rubber materials.     

氧化铜/二氧化硅多孔复合材料的制备及其对亚甲基蓝的吸附性能

采用聚乙二醇（PEG）为模板,通过溶胶凝胶法-水热法制备出CuO/SiO2多孔复合材料,使用FTIR、HRTEM、XRD和BET等技术手段对目标产物进行了表征;研究添加CuO质量及反应温度等反应条件对复合材料的孔结构特征的影响。 用目标产物作为吸附材料,研究了其对有机染料亚甲基蓝的吸附性能,结果表明,CuO/SiO2多孔复合材料对亚甲基蓝具有良好的吸附效果,尤其是含CuO质量分数为15%的样品在用量0.015 g、体系pH=9、搅拌时间为2 h的条件下,对10 mL亚甲基蓝（4 mg/L）的去除率最高可达97.17％。 对吸附的过程和机理进行了初步探讨。     

Removal of reactive dye brilliant red HE-3B from aqueous solutions by hydrolyzed polyacrylonitrile fibres: equilibrium and kinetics modelling

A cheap and efficient fibrous hydrolyzed polyacrylonitrile (HPAN) sorbent was obtained by alkaline hydrolysis of Romanian polyacrylonitrile fibres. Scanning electronic microscopy and infrared spectroscopy were used to characterize the hydrolyzed product and to confirm its functionalization. The adsorptive potential of the proposed sorbent for reactive dye Brilliant Red HE-3B removal from aqueous solutions of pH=2 was examined by the batch technique as a function of dye concentration, temperature solution and contact time. The Freundlich, Langmuir and Dubinin-Radushkevich adsorption models were applied to describe equilibrium sorption data and to determine the corresponding isotherm constants. The thermodynamic parameters ΔG, ΔH and ΔS were also determined; the values obtained show that sorption of reactive dye on HPAN fibres is a spontaneous, endothermic and entropy-driven process. The kinetics of sorption of the reactive dye were analyzed using pseudo-first order and pseudo-second order kinetic models. The kinetic data fitted well to pseudo-second order kinetics, indicating the chemisorption of reactive dye onto the fibrous sorbent. The sorption mechanism of the dye onto hydrolyzed fibres was confirmed by FTIR spectroscopy. The dye-loaded HPAN sorbent can be regenerated by treatment with 0.1M NaOH and the regenerated sorbent may be reused in several adsorption-desorption cycles. The results of this study provided evidence that the HPAN fibres are effective for removing reactive dye Brilliant Red HE-3B from aqueous effluents.      

A core-shell magnetic mesoporous silica sorbent for organic targets with high extraction performance and anti-interference ability

C(18)-functionalized mesoporous silica shell was successfully fabricated on the surface of an Fe(3)O(4)/SiO(2) core to obtain an Fe(3)O(4)/SiO(2)/SiO(2)-C(18) magnetic microsphere. The microsphere exhibited high extraction efficiency to organic targets and strong anti-interference ability to natural organic matter. It could be easily isolated from water solution after extraction.