Removal of 1-naphthylamine from aqueous solution by multiwall carbon nanotubes/iron oxides/cyclodextrin composite

The adsorption of 1-naphthylamine on multiwall carbon nanotubes/iron oxides/β-cyclodextrin composite (denoted by MWCNTs/iron oxides/CD) prepared by using plasma-induced grafting technique was investigated by batch technique under ambient conditions. The effect of contact time, pH, adsorbent content, temperature and initial 1-naphthylamine concentration, on 1-naphthylamine adsorption to MWCNTs/iron oxides/CD was examined. The adsorption of 1-naphthylamine on MWCNTs/iron oxides/CD was dependent on pH, adsorbent content, and temperature. The 1-napthylamien was adsorbed rapidly at the first 50h, and thereafter attained the adsorption saturation at 80h. The adsorption kinetic data were well described by the pseuso-second-order rate model. The adsorption isotherms were fitted by the Langmuir model better than by the Freundlich model. The maximum adsorption capacity of 1-naphthylamine was 200.0mg/g. The adsorption thermodynamic parameters of standard enthalpy (ΔH(0)), standard entropy changes (ΔS(0)), and standard free energy (ΔG(0)) were calculated from temperature dependent adsorption isotherms. The values of ΔH(0) and ΔG(0) suggested that the adsorption of 1-naphthylamine on MWCNTs/iron oxides/CD was endothermic and spontaneous. The electron-donor-acceptor interaction, Hydrophobic interaction, and Lewis acid-base interaction may play an important role in 1-naphthylamine adsorption. The results show that MWCNTs/iron oxides/CD is a promising magnetic nanomaterial for the preconcentration and separation of organic pollutants from aqueous solutions in environmental pollution cleanup.     

Formation of ordered metal nanowire-inorganic salt composites

A new phenomenon accompanying the electrolysis of salts has been observed, whereby an ordered composite is formed under certain conditions (electrolyte composition, current density). The composite comprises an inorganic salt crystal penetrated by metal nano- and microwires. This phenomenon can serve as a basis for the technology of oriented and ordered nanowire array synthesis.     

Periodically ordered nanoscale islands and mesoporous films composed of nanocrystalline multimetallic oxides

Innovative strategies to produce well-defined nanoparticles and other nanostructures such as nanofibres, quantum wells and mesoporous materials have revitalized materials science for the potential benefit to society. Here, we report a controlled process, involving soft-chemistry-based deposition, template-assisted mesostructured growth, and tuned annealing conditions that allows the preparation of ordered mesoporous crystalline networks and mesostructured nano-island single layers, composed of multicationic metal oxides having perovskite, tetragonal or ilmenite structures. This strategy to obtain meso-organized multi-metal-oxide nanocrystalline films (M(3)NF) bridges the gap between conventional mesoporous materials and the remarkable properties of crystalline ternary or quaternary metallic oxides. Nanocrystalline mesoporous films with controlled wall thickness (10-20 nm) of dielectric SrTiO(3), photoactive MgTa(2)O(6) or ferromagnetic semi-conducting Co(x)Ti(1-x)O(2-x) were prepared by evaporation-induced self-assembly (EISA) using a specially designed non-ionic block-copolymer template. A tuned thermal treatment of the mesoporous films permits the transfer of the wall structure into nanocrystallites, with all tectonic units being tightly incorporated into mechanically stable ordered tri- or bidimensional nanocrystalline networks. This methodology should allow multifunctionalization, miniaturization and integration during development of devices such as smart sensors and actuators, better-performing photocatalysts, and fast electrochromic devices. On the other hand, organized arrays of dispersed ferromagnetic or ferroelectric nanoparticles are promising materials for spintronics and for cheap, non-volatile 'flash' memories.     

Synthesis of Inorganic Nanotubes

Nanotubes constitute an exciting class of one‐dimensional nanomaterials of which carbon nanotubes are recognized widely as materials of importance. The possibility of having inorganic nanotubes was recognized early in the 1990s, accompanied by the report of nanotubes of MoS₂ and WS₂. Since then, nanotubes of several inorganic materials have been prepared and characterized. While nanotubes of metal chalcogenides and oxides form a high proportion of the inorganic nanotubes investigated hither to, nanotubes of many other materials have also been prepared and characterized. Several synthetic strategies including both physical and chemical methods have been employed, of which the use of templates, precursors, and hydro‐ or solvothermal methods are prominent. In this article, we shall present a brief account of the present status of the synthesis of nanotubes of elemental materials as well as binary and complex metal oxides, chalcogenides, pnictides and carbides.     

Preparation of a Cation Exchanger from Cork Waste：Thermodynamic Study of the Ion Exchange Processes

An ion exchanger was prepared by sulfonation of cork-waste chars. The exchange properties of the resultant material were characterized using Na+, Ca2+ or Fe3+ aqueous solutions. The content of metal ions in the solutions were determined by atomic absorption spectrometry. On the basis of the results obtained, the chemical equilibrium and its thermodynamic aspects related to the ion exchange process were studied. It was found that equilibrium constant K varies by the order: Na+0 and △5°>0, with -△G° following the sequence: Ca2+>Na+>Fe3+.     

Recent Advances in Inorganic Heterogeneous Electrocatalysts for Reduction of Carbon Dioxide

In view of the climate changes caused by the continuously rising levels of atmospheric CO₂, advanced technologies associated with CO₂ conversion are highly desirable. In recent decades, electrochemical reduction of CO₂ has been extensively studied since it can reduce CO₂ to value‐added chemicals and fuels. Considering the sluggish reaction kinetics of the CO₂ molecule, efficient and robust electrocatalysts are required to promote this conversion reaction. Here, recent progress and opportunities in inorganic heterogeneous electrocatalysts for CO₂ reduction are discussed, from the viewpoint of both experimental and computational aspects. Based on elemental composition, the inorganic catalysts presented here are classified into four groups: metals, transition‐metal oxides, transition‐metal chalcogenides, and carbon‐based materials. However, despite encouraging accomplishments made in this area, substantial advances in CO₂ electrolysis are still needed to meet the criteria for practical applications. Therefore, in the last part, several promising strategies, including surface engineering, chemical modification, nanostructured catalysts, and composite materials, are proposed to facilitate the future development of CO₂ electroreduction.     

识别Cu2+的中氮茚衍生物荧光探针分子的设计与合成

合成了荧光性能良好的中氮茚化合物5,用IR、1 H NMR等手段表征其结构;研究各种金属离子对其荧光性能的影响,结果表明Cu2+能显著地猝灭其荧光,而余者则几无影响;其紫外吸收峰值随着Cu2+浓度的增加而增加,表明二者存在着化学反应。此化合物有望作为重金属离子Cu2+的荧光探针。     

Inside Front Cover: Topological Transformation of Vesicular Mesostructured Silica (Adv. Mater. 5/2005)

The micrometer‐scale self‐assembly behavior of MCM‐41‐type mesostructured silica is shown by Tang and co‐workers on p. 578 through study of a family of vesicular mesostructured silica with topology genera from 1 to 0. The inside cover shows a series of typical vesicular structures with different topologies on the micrometer scale. A better understanding of the micrometer‐scale self‐assembly behavior provides a guide for the rational design of new hierarchical organic–inorganic composite materials, and may also shed new light on the natural biosilicification process.     

Recent Advances in 2D Inorganic Nanomaterials for SERS Sensing

Surface‐enhanced Raman spectroscopy is a powerful and sensitive analytical tool that has found application in chemical and biomolecule analysis and environmental monitoring. Since its discovery in the early 1970s, a variety of materials ranging from noble metals to nanostructured materials have been employed as surface enhanced Raman scattering (SERS) substrates. In recent years, 2D inorganic materials have found wide use in the development of SERS‐based chemical sensors owing to their unique thickness dependent physico‐chemical properties with enhanced chemical‐based charge‐transfer processes. Here, recent advances in the application of various 2D inorganic nanomaterials, including graphene, boron nitride, semiconducting metal oxides, and transition metal chalcogenides, in chemical detection via SERS are presented. The background of the SERS concept, including its basic theory and sensing mechanism, along with the salient features of different nanomaterials used as substrates in SERS, extending from monometallic nanoparticles to nanometal oxides, is comprehensively discussed. The importance of 2D inorganic nanomaterials in SERS enhancement, along with their application toward chemical detection, is explained in detail with suitable examples and illustrations. In conclusion, some guidelines are presented for the development of this promising field in the future.     

One pot synthesis of mesostructured non-silica oxides nanocrystallites

Some typical worm-like mesoporous non-silica oxides, titania, zirconia, and dopants-incorporated zirconia oxides, with homogeneous nanocrystalline framework and narrow pore-size distribution have been synthesized via a facile process templated from composite surfactant of a long chain poly block copolymer combined with non-ionic alkyl-PEO surfactant (Brij56) under the hydrothermal condition. Bi- or even multi-component zirconia-based composites with further addition of other oxide compositions can also be obtained with well-defined mesoporous structure and nanocrystalline framework. These mesostructured oxides/composite oxides show high surface area, well-crystallization framework, and high thermal stability. XRD, nitrogen adsorption analysis, TEM, and EDX were used for the structural characterizations. The use of non-ionic block-copolymer surfactant is believed to be responsible for the crystallization of mesoporous framework and high thermal stability at high temperature without structural collapse.     

QCM-D analysis of binding mechanism of phage particles displaying a constrained heptapeptide with specific affinity to SiO2 and TiO2

A growing number of peptides capable of specifically recognizing inorganic materials have been reported, incrementally increasing the potential to harness peptides as a biological linker to bridge biomolecules and inorganic materials at nanometer scale. In this study, we identified disulfide bond constrained heptapeptides with specific binding affinity to SiO2 and TiO2 using a phage display technique. Interestingly, two of the phage surface displayed peptides enriched with basic amino acid residues, STB1 (HKKPSKS) and STB2 (TKRNNKR), showed a cross binding affinity to both metal oxides. To understand the underlying binding mechanism, binding behaviors of phage particles harboring the STB1 (a high-frequency heptapeptide exhibiting dual binding affinity to both metal oxides) were investigated in a wide pH range using quartz crystal microbalance with energy dissipation measurement (QCM-D). It was found that the binding of STB1-harboring phages to the two metal oxides was clearly mediated by the peptide moiety displayed on the phage surface in a pH-dependent manner, indicating that the binding is largely governed by electrostatic interaction. Furthermore, the interpretation of QCM-D signals (i.e., frequency shift and dissipation shift), with the aid of AFM image analysis of the phage particles bound on the surface of the two metal oxides, elucidated whether the nature of phage (or the displayed peptide) binding to the metal oxides is largely specific or nonspecific.     

Layer by layer deposition of hydroxyapatite onto the collagen matrix

Layer by layer (LbL) deposition is a useful method for deposition of many inorganic (including metals, oxides and phosphates) and organic (including polymers and proteins) components on a large range of substrates. The LbL deposition of hydroxyapatite (HA) onto a collagen matrix involves HA synthesis on the collagen matrix starting from electrically charged precursors such as Ca²⁺ and PO₄³⁻ at a proper pH to precipitate the desired calcium phosphate.The LbL deposition process was continuously monitored in order to study the amount of HA deposited in each layer. The deposition of the first layers of HA was concluded to be highly influenced by the collagen matrix. When the collagen matrix is crosslinked with glutaraldehyde, the matrix structure is not modified during the deposition, and the porosity will decrease with the number of layers until saturation is reached. Following pore saturation, HA will be only deposited onto the mineralized collagen matrix surface. The obtained composite materials were characterized by XRD, SEM, DTA-TG and FTIR.     

Comparative study of synthesis, characterization and electric properties of polypyrrole and polythiophene composites with tellurium oxide

The study involves the synthesis of polypyrrole (PPY) and polythiophene (PTP) composites of TeO₂ via in situ oxidative polymerization procedure. These composites were characterized by FTIR, XRD and SEM, which proves the successful chemical synthesis of PPY, PTP and their composites. FTIR absorption peaks confirms the insertion of TeO₂ in the backbone of PPY and PTP and also justifies the strong interaction of TeO₂ with PTP than PPY, which is responsible for a significant increase in the conductivity value in case of PTP composite than PPY composite, which ensures its better capability in future electronics. Thermal analysis shows no change in thermal stability unlike composites of PPY and PTP with other metal oxides, hence rules out the application of these composites for higher temperature purposes, however, the PTP composite material has shown the stability up to 200 °C which ensures its use in low temperature applications. The compactness, ordered morphology, better conjugation or chain length and orientation of TeO₂ with PTP backbone are responsible for more conductivity of PTP composite than PPY.     

新型两亲性嵌段共聚物导向合成有序大孔径介孔材料的研究进展

自从1992年首次报道介孔氧化硅分子筛M41S系列以来, 人们采用各种商业化表面活性剂为模板, 合成了多种骨架组成、丰富的有序介观结构、不同孔径尺寸的介孔材料, 并将其应用在能源、环境、催化等诸多领域。然而, 由于常规商业化模板剂的分子量大小有限, 合成的介孔材料具有较小的孔径(< 8.0 nm), 从而极大地限制了其面对大尺寸客体分子的相关应用。此外, 利用常规模板剂难以合成出具有晶化墙壁的介孔金属氧化物材料。近年来, 大分子量两亲性嵌段共聚物相继被报道用来合成新型介孔材料, 本文将综述基于这种嵌段共聚物为模板剂合成各种具有大孔径和晶化墙壁介孔材料的研究进展。     

石墨烯基有序介孔金属氧化物复合材料的制备及研究进展

综述了以石墨烯作为载体,利用有序介孔金属氧化物特殊的3D结构,以及两者共存产生的协同效应,开发系列新型石墨烯基有序介孔金属氧化物复合材料的最新研究进展。介绍了本课题组在有序介孔金属氧化物的可控合成、与石墨烯的有效复合以及复合材料的光电性能等方面的探索性研究。着重对石墨烯基有序介孔金属氧化物复合材料的制备方法、形成机理及其在催化、电化学、传感和能量储存等领域的最新应用进行概述,并展望了其未来的发展趋势。     

The oxidative degradation of 2-mercaptobenzothiazole at the interface of beta-MnO2 and water

To investigate the oxidative degradation of organic pollutants at the interface of manganese oxides and water, beta-MnO2 was prepared and its crystal structure and the specific surface area were examined by X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) methods, respectively. 2-Mercaptobenzothiazole (MBT) as a model chemical was used to study its oxidative degradation reaction in beta-MnO2 suspension. The experimental results showed that MBT was effectively degraded and mineralized into SO4(2-) and NO3- by beta-MnO2. In the meantime, it was found that beta-MnO2 could be reductively dissolved, and aqueous and adsorbed Mn2+ was generated. The kinetics of MBT degradation by beta-MnO2 is a function of initial MBT concentration, beta-MnO2 dosage and pH value. At pH 4.6, apparent reaction orders with respect to initial MBT concentration and beta-MnO2 dosage were determined to be 0.88 and 0.27, respectively. The initial reaction rate (rinit) is of pH dependence with a reaction order of -0.36. The thermodynamics of MBT degradation by beta-MnO2 was also investigated, and the apparent activation energy was calculated to be 5.62 kJ/mol. The inhibited effect of carboxylic acids (oxalic, citric, tartaric, and malic acids) or metal ions (Ni2+, Ca2+, Mn2+ and Cr3+) on the oxidative degradation of MBT by beta-MnO2 was also investigated. This investigation will give some new insights for understanding the interaction of organic pollutants with manganese oxides in natural soils and sediments.     

原位相转化反应制备的金属/金属氧化物用于析氧反应

金属/金属氧化物复合材料凭借其独特的界面和电子结构已被广泛设计合成,并应用于碱性溶液中电催化析氧反应的电催化剂.然而,如何设计并获得丰富的金属/金属氧化物界面和均匀分散的金属相仍是一个挑战.此外,金属和金属氧化物在增强电催化活性方面的协同机理依然不清晰.本文以金属氧化物为基体,通过锂诱导的转化反应,制备了具有丰富界面和...     

Shaping Colloidal Rutile into Thermally Stable and Porous Mesoscopic Titania Balls

High crystallinity and controlled porosity are advantageous for many applications such as energy conversion and power generation. Despite many efforts in the last decades, the direct synthesis of organic–inorganic composite materials with crystalline transition metal oxides is still a major challenge. In general, molecules serve as inorganic precursors and heat treatment is required to convert as‐synthesized amorphous composites to stable crystalline materials. Herein, an alternative approach to the direct synthesis of crystalline polymer–metal oxide composites by using a spherical polyelectrolyte brush as the template system is presented. Pre‐synthesized electrostatically stabilized rutile nanocrystals that carry a positive surface charge are used as inorganic precursors. In this approach, the strong Coulomb interactions between anionic polyelectrolyte brush chains and cationic crystalline rutile colloids, whose surfaces are not capped and therefore reactive, are the key factors for the organic–inorganic crystalline composite formation. Stepwise calcination first under argon and followed with a second calcination in air lead to the complete removal of the polymer template without collapse and porous rutile balls are obtained. The results suggest that any colloids that carry a surface charge might serve as inorganic precursors when charged templates are used. It is expected that this hierarchical route for structuring oxides at the mesoscale is generally applicable.     

High-surface area inorganic compounds prepared by nanocasting techniques

This paper is a survey of the nanocasting methods used for the synthesis of nanosized and nanostructured inorganic compounds. Special attention is paid to the use of porous materials such as mesostructured silica, silica gel, and carbonaceous materials as hard templates for the preparation of metallic oxides. General aspects concerning the applications of materials obtained by hard-templating procedures are also reviewed.     

Mass spectrometric determination of the coordination geometry of potential copper(II) surrogates for the mammalian prion protein octarepeat region

The N-terminal domain of mammalian prion proteins contains several tandem repeats of the octapeptide PHGGGWGQ, each one capable of selectively binding up to 1 equiv of Cu2+. Under saturating conditions Cu2+ is known to coordinate the HGG portion of the repeat sequence via the histidine imidazole side chain, two deprotonated amide N-atoms, and a backbone carbonyl O-atom. Using appropriate selection criteria, we have generated a short list of candidate metal ions (Co3+, Ni2+, Pd2+, Pt2+) that can serve as potential surrogates for Cu2+. The selected metal ions were screened for binding interactions with the OR-derived peptide fragment AcHGGGWNH2 (Ac = acetyl, amino acid residues in italics) using electrospray ionization mass spectrometry. The coordination geometries of these metal ions with the synthetic OR peptide were subsequently determined from fragment analysis using collision-induced dissociation tandem mass spectrometry. Our results indicate that, although Co3+, Pd2+, and Pt2+ all bind to the OR fragment via the peptide backbone to varying extents, each of these metal ions appears to associate with the peptide in a unique manner, which is distinct from the way in which Cu2+ is coordinated. This work illustrates the extremely strong selectivity for Cu2+ of this highly conserved region of the mammalian prion protein.