用于吸附贵重金属、有色金属、有毒金属及稀有金属的有机硅吸附剂

概述了有机硅吸附剂的结构、类型及其官能团的种类与被吸附元素的关系,详细介绍了用于吸附贵重金属、有色金属和有毒金属、稀土元素及放射性元素的有机硅吸附剂的官能团种类及其吸附特性,以及在化工废水、冶金污水、腐蚀性废水的无害化处理中的应用。     

Metal and metal oxide nanoparticle synthesis from metal organic frameworks (MOFs): finding the border of metal and metal oxides

Herein, for the first time, we report a generalized strategy for the successful synthesis of highly crystalline metal and metal oxide nanoparticles embedded in a carbon matrix by the controlled thermolysis of metal organic frameworks (MOFs). The rationalized synthesis strategy of a broad range of metal and metal oxides nanoparticles, such as Cu/CuO, Co/Co(3)O(4), ZnO, Mn(2)O(3), MgO and CdS/CdO, by thermolysis of MOFs demonstrates for the first time that metal ions with a reduction potential of -0.27 volts or higher present in MOFs always form pure metal nanoparticles during thermolysis in N(2), whereas metal ions with a reduction potential lower than -0.27 volts form metal oxide nanoparticles during thermolysis in N(2). Another point of interest is the fact that we have found a unique relationship between the nanoparticle size and the distance between the secondary building units inside the MOF precursors. Interestingly, the crystallinity of the carbon matrix was also found to be greatly influenced by the environment (N(2) and air) during thermolysis. Moreover, these nanoparticles dispersed in a carbon matrix showed promising H(2) and CO(2) adsorption properties depending on the environment used for the thermolysis of MOFs.     

金属预合金粉末与单质粉末在应用中的配伍特点研究

针对金属结合剂超硬材料工具常用单质Fe、Cu及预合金粉末的性能特点,结合生产实践,总结分析了其在生产实际中的应用特点及二者在配合应用过程中的配伍特性,从粉末的氧含量、粒度、形貌、松比的配合要求等方面开展了一些基本研究,阐述了二者协同作用时所应控制的一些基本要素,为单质及预合金粉末在生产实践中的应用提供了指导帮助。     

负载型金属催化剂表面金属分散度的测定

简要介绍了几种催化剂表面金属分散度的测定方法,包括静态化学吸附法、动态化学吸附法、X射线光电子能谱法(XPS)、X射线衍射宽化法(XRD)和透射电子显微镜法(TEM)。同时,对这几种方法的适用范围、局限性和测定结果的一致性进行了讨论和总结。     

Stability of supported metal and supported metal oxide combustion catalysts

Catalysts used for high-temperature combustion of light hydrocarbons must maintain high activity over long time intervals by avoiding excessive sintering and deactivation in the hot and corrosive combustion environment. The sintering resistance and chemical stability of catalytically active phases is a key technical problem that must be solved for the development of commercially viable combustion catalysts. All noble metals and transition metal oxides that are catalytically active rapidly sinter at temperatures required for high combustion rates. Advanced materials used in the development of stable catalysts include highly sintering-resistant hexaaluminate supports for dispersion of noble metals, chemically and thermally stable supporting oxides for active transition metal oxides, and single-phase, substitutionally activated, sintering-resistant complex metal oxides. This paper will review deactivating phenomena, such as sintering and vapor transport and assess recent progress in the development of durable combustion catalysts.     

Shaping RNA structures with metal ions and metal ion complexes

The research in our laboratory focuses on the role of metal ions and their complexes in structure formation and folding of nucleic acids. Large catalytic RNAs, like group II introns and some riboswitches, as well as shorter RNAs and DNAs containing modified nucleotides for the assembly of nanodevices are examined. Abundant metal ions like Mg2+ or natural metabolites like coenzyme B12 are in the center of interest, but also other metal ions, complexes thereof and B12 derivatives are applied with the aim to understand the largely unknown and manifold non-covalent interactions with nucleic acids. We apply a multitude of techniques, including potentiometric pH titrations, NMR spectroscopy, X-ray crystallography, gel electrophoresis and single molecule FRET experiments. Here we briefly summarize each of our research topics emphasizing the interaction of coenzyme B12 and its derivatives with the btuB riboswitch of E. coli. This highly conserved sequence, found in the 5'-untranslated region (5'-UTR) of the btuB mRNA, is involved in the regulation of the btuB protein expression. After a summary on the historical discovery of such riboswitches and their mechanism of action, we shortly focus on our own contributions to understand the structural equilibrium, high affinity and selectivity of the interaction between this specific RNA sequence and the largest and most complex cellular metabolite, coenzyme B12.     

Faradaic rectification study of the metal/metal ion reactions

The kinetic parameters for Ag⁺/Ag and Cu²⁺/Cu reactions at the equilibrium potential and in the absence of dc polarisation have been obtained using the faradaic rectification method at audio frequencies. The values of transfer coefficients, ion exchange current densities and apparent rate constants, obtained for the two reactions at 27°C using 1·0mM of each of the Ag⁺ and Cu²⁺ in 1·0M KNO₃, are respectively 0·22; 7·3mA/cm²; 3·6·10^?3 cm/s and 0·45; 10·7 mA/cm²; 1·1×10^?4cm/s. These data are comparable to those reported in the literature. For obtaining reliable and reproducible results for the studies with metal/metal ion reactions suitable experimental conditions have been described.     

Antiviral metal complexes

The initial events (virus adsorption and fusion with the cells) in the replicative cycle of human immunodeficiency virus (HIV) can serve as targets for the antiviral action of metal-binding compounds such as polyanionic compounds (polysulfates, polysulfonates, polycarboxylates, polyoxometalates, and sulfonated or carboxylated metalloporphyrins), bicyclams and G-octet-forming oligonucleotides. The adsorption and fusion of HIV with its target cells depends on the interaction of the viral envelope glycoproteins (gp 120) with the receptors (CD4, CXCR4) at the outer cell membrane. We are currently investigating how the aforementioned compounds interfere with these viral glycoproteins and/or cell receptor.     

In-situ TEM observation of internal metal inside metal filled carbon fiber

There has been a considerable amount of research on MFCNTs and MFCNFs; however, research on the behavior of the internal metal used in MFCNF under heating has been limited. Therefore, in this study, an MFCNF was heated and the behavior of the internal metal was investigated using in-situ TEM observations. The internal metal used in the MFCNF did not melt. It was supposed that the non-melting was because of the high pressure of the internal metal resulting from a difference in the coefficients of linear thermal expansion of the graphite wall of the MFCNF and the internal metal. The pressure of the internal metal was calculated; it was approximately 12 GPa when the MFCNF was heated at 1500 °C.     

Fracture of metal/polymer/metal assemblies: Viscoelastic effects

The purpose of this work is to link the polymer viscoelastic properties (especially its relaxation time) and the adhesive behaviour of steel/polymer/steel assemblies. A wedge test device developed in the laboratory allows one to introduce the wedge into the assembly at a controlled speed and to follow the crack propagation with a camera-equipped microscope. The adherence energy (calculated from the equilibrium crack length) and the crack propagation rate are measured for different wedge introduction rates. Polymer equivalent relaxation time is determined for each introduction rate according to the time-temperature superposition principle. Relations between adherence energy, crack propagation rate, and calculated equivalent relaxation time values are proposed. These quantitative relations confirm the major influence of polymer viscoelastic properties on the rate sensitivity of adhesive behaviour.     

Effects of metal source in metal substitution of lithium manganese oxide spinel

Usefulness of W substitution for improvement of battery performance of LiMn₂O₄ cathode was investigated. Small amounts of tungsten were incorporated into LiMn₂O₄ spinel instead of available Mn. For this purpose, two sources of tungsten (metallic W or WO₃) were examined. W concentration and source have significant influence on both morphology and electrochemical behavior of W-substituted LiMn₂O₄ spinels. W substitution of LiMn₂O₄ spinel can lead to the formation of uniform spinel particles and improved battery performance. Cyclic voltammetric behaviors of the samples were examined in an aqueous solution, and Li diffusion process was investigated for different cases. The best case was the LiW_0.01Mn_1.99O₄ spinel prepared from metallic W powder, as exhibits excellent rate capability, but better cycleability was observed for the LiW_0.01Mn_1.99O₄ spinel prepared from WO₃. This means that because of significant influence of the dopant source, this parameter should be chosen in respect with the desire improvement.     

Role of transition metal oxides in metal dusting: Density functional study

Density function theory was applied to study the mechanisms and energetics of two major metal dusting processes represented by Boudouard and steam-carbon reactions on the FeO(100) surface. Cluster models were utilized to represent the surface. The chosen cluster model was validated by examining CO adsorption binding energies on clusters of various sizes. We show that the lattice relaxation has a relatively small effect on the adsorption. The reaction process involving direct abstraction of O from the surface by CO was excluded from consideration of the overall dusting processes due to unfavorable energetics. Minimum energy path calculations were carried out to investigate the reaction mechanisms. It was found that both the Boudouard and steam-carbon reactions are thermochemically and kinetically unfavorable on transition metal oxide surfaces. Detailed insight into the reaction mechanisms was obtained by following the reaction trajectories and analyzing the electron population distribution along the reaction paths. This study elucidates the empirical observation that metal oxide can often minimize metal dusting.     

Structural effects on dynamic features of sandwich metal/polymer/metal

A theoretical approach to the mechanical coupling between phases in metal/polymer/metal sandwich composites is developed assuming perfect interfaces. Comparisons between experimental dynamic mechanical spectroscopy and theoretical results are made with special attention to the geometrical characteristics. Unexpected results concerning the dependence on the width of the specimen are explained using the strain energy method. The polymer thickness influence is explained only by structural effects instead of the interface effects often found in the literature. The temperature of the sandwich loss factor peak is revealed to greatly depend on the specimen dimensions. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2493–2505, 1997     

有色金属矿山重金属废水深度处理技术研究

为满足某有色金属矿山重金属废水深度处理要求,采用树脂材料吸附法进行深度处理技术研究,结果表明:D402型树脂对Pb(Ⅱ)、Cd(Ⅱ)有很强的吸附能力,原水Pb(Ⅱ)为1 180 μg/L、Cd(Ⅱ)为670 μg/L时,在温度298 K、pH=6.0、流速16.8 m/h的条件下,单周期Pb(Ⅱ)、Cd(Ⅱ)分别达标可通过水样为6 800 BV和2 100BV,混合水样达标通过量为1 900 BV,出水满足《地表水环境质量标准》(GB 3838-2002)Ⅲ类水标准的要求.     

Epoxidized natural rubber as a dry adhesive for metal to metal bonding

Epoxidized natural rubber with an epoxide content of 50 mol% was found to be a novel adhesive for bonding aluminium to aluminium. The conditions for obtaining maximum joint strength were optimized by varying the mastication time and moulding conditions such as time, temperature, and pressure.     

Polymer-supported transition metal clusters

Summary The synthesis of appropriate monomers bearing alkylidyne tricobaltnonacarbonyl cluster or sulfido tricobalt heptacarbonyl cluster is described. Organometallic copolymers are obtained by free-radical copolymerisation with other vinyl monomers. Direct metallation of macromolecules containing the dithioester or the thioamide functional groups was also studied. We show that the copolymerisation method is more convenient for the synthesis of pure materials containing a variable amount of definite cluster units. The potentiality of these new organometallic polymers with regard to homogeneous catalysis and for the modification of electrode surfaces is also discussed.