Single point electrodeposition of nickel for the dissymmetric decoration of carbon tubes

Dissymmetric micro- and nanoobjects are of enormous interest in many areas ranging from molecular electronics to targeted drug delivery. So far it has been quite difficult to synthesize dissymmetric objects at these scales and most approaches are based on using interfaces to break the symmetry. Only a few bulk procedures are known so far to produce the so-called Janus-type objects. We report here a simple approach for the bulk generation of dissymmetric micro- and nanoobjects, especially carbon tubes (CTs), based on a known, but so far underestimated electrochemical principle, namely bipolar electrodeposition. A suspension of CTs is introduced in a capillary containing an aqueous nickel salt solution and a high electric field is applied to orientate and polarize the individual tubes. During their transport through the capillary under sufficient polarization, each tube is the site of water oxidation at one end, and of Ni²⁺ reduction at the other one. The resulting nickel deposit at one end of the tube allows manipulation of the objects with the help of a magnetic field.     

Bipolar Electrochemistry,a Focal Point of Future Research

Bipolar electrochemistry is a conventional method based on the polarization of an isolated substrate under an applied electric field. This technique has been applied to electrolysis, corrosion, and other areas of chemical engineering since the twentieth century. However, it has been recognized as a powerful tool in many modern domains after water splitting has been demonstrated to be possible using micrometer-sized bipolar electrodes. Modifying inorganic objects in novel ways, such as creating electrical contacts between metal particles using directed electrochemical growth or shaping and exploring the micro- and nanoworld are some of the new applications in this field. Fabrication of electronic devices, electroanalytical purposes, generation of molecular and material gradients, functionalization of single micro- and nanopores, synthesis of Janus particles, design of swimmers, and asymmetric modification of nanoparticles will be discussed in this article as a focal point of future research in bipolar electrochemistry.     

α-蒎烯电化学法合成桃金娘烯醛

以α-蒎烯为原料,采用电化学方法,将α-蒎烯阳极氧化生成桃金娘烯醛,阳极材料为C—Cr2O3,乙醇为溶剂,NaBF4为支持电解质．用正交法得出合成的最佳工艺条件．产物的收率达61％。     

电化学技术降解有机废水研究进展

综述了电催化氧化、光电催化、超声电化学、三维电极电化学技术降解有机废水的研究与应用进展,重点介绍了电化学技术协同降解有机废水的发展现状,对各种电化学方法进行了阐述,探讨了电化学技术降解有机废水的发展趋势,展望了降解有机废水今后的重点研究方向。     

Non-spherical Janus microgels driven by thiolated DNA interactions

Janus poly (N-isopropylacrylamide)-co-acrylic acid/Au microgels that resemble a “snowman”, “dumbbell”, and an “abalone” were prepared by thermally evaporating a layer of Au on half of the microgel surface, followed by exposure to thiolated single-stranded DNA with complementary sequences. We hypothesize that when the complementary single-stranded DNA attached to the Au forms the more stable double strand, the Au reorganizes on the microgel surface, yielding the observed unique Janus particle structures.     

复极性三维电极处理硝基苯废水中各影响因子分析

以不锈钢片为阳极,石墨为阴极,经吸附饱和的活性炭粒子为填充材料,研究了复极性三维电极法的处理硝基苯废水的时各影响因子的相互作用。通过正交实验确定了复极性三维电极处理硝基苯废水的最佳操作条件为:电解电压10 V,活性炭投加量25 g,反应时间50 min,初始pH值为5。此条件下废水COD的去除率普遍大于75%。     

Self-assembly of particles—The regulatory role of particle flexibility

Aspects of the self-assembly of particles, which uses nanometer or micrometer sized building blocks to bridge the gap between microscopic and macroscopic scales, are reviewed. Particle self-assembly has been the focus of considerable research in recent years because it can lead to superstructures with a complexity inaccessible by molecular self-assembly, and functionalities entirely different from or superior to those of the primary particles. Examples in molecular self-assembly suggests that anisotropic interactions could be useful in promoting particle self-assembly, with the exception of colloidal crystallization, which requires particles of uniform size and shape. Anisotropic particles prepared by surface modification of precursor particles are often rigid and submicron or micron sized, and thus relatively strong isotropic van der Waals interactions tend to resist self-assembly into regular superstructures. In addition, the relatively large contact area between particles needed for a sufficient binding enthalpy to stabilize a superstructure is difficult for rigid spherical particles. In contrast, flexible anisotropic polymeric particles dispersed in solvents have been shown to self-assemble into various superstructures. The flexibility of primary anisotropic particles enables them to fuse and stabilize into a superstructure. Some flexible and multi-component particles that are isotropic in common solvents can undergo deformation and sufficient material redistribution to anisotropically self-assemble into regular superstructures in selective solvents. The self-assembly is also driven by anisotropic interactions, which is induced during self-assembly rather than in the particles as synthesized. This review focuses on recent achievements in soft particle self-assembly and describes briefly the advancements in rigid particle self-assembly. The presentation is divided into discussion of self-assembly by the colloidal crystallization of isotropic rigid particles, anisotropic rigid particles, anisotropic soft particles and isotropic soft particles, in that order.     

煤的电化学脱硫及其进展

综述了煤炭电化学脱硫的原理 ,借助煤在电解槽阳极发生的电化学氧化反应将煤中的无机硫或有机硫氧化成可溶于水的硫化物 ,介绍了电解脱硫设备及工艺流程、电化学脱硫技术发展方向及趋势 ,认为该方法的显著特点是常温常压下操作 ,工艺简便 ,能量回收率高 ,并可联产大量高纯氢气 ;同时也指出了煤炭电化学脱硫技术中存在的问题     

Synthesis and electrochemistry of acetylacetonatolanthanide(III)- phthalocyaninates

The synthesis and electrochemistry of acetylacetonatolanthanide(III)phthalocyaninates are reported. Two new kinds of lanthanide complexes Li[Pc]Ln(acac)₂] and (Pc)Ln(acac) were obtained where Ln is the trivalent ions of Eu, Gd, Dy, Tb, Ho, Er, Tm, Lu, and Pc is the dianion of phthalocyanine and acac is the acetylacetonate anion. These complexes were characterized by infrared and electronic absorption spectroscopy. An overall oxidation reduction mechanism at a platinum electrode in dimethyl sulfoxide is presented.     

Differences in physico-mechanical behaviors of resol(e) and novolac type phenolic resin based composite bipolar plate for proton exchange membrane (PEM) fuel cell

Composite bipolar plates for Proton Exchange Membrane Fuel Cell (PEMFC) are prepared by compression molding technique using polymer as binder and graphite as electric filler material with some other reinforcements. Study on the effect of resole and novolac type phenolic resin on the properties of composite bipolar plate, such as bulk density, porosity, bulk conductivity, hardness, flexural strength, etc. shows that both of the resin shows different physico-mechanical properties. Moreover, single cell performance analysis also shows variation for resole and novolac based composites. A novel concept of triple continuous structure to provide graphite polymer blends with high electrical conductivity, high shore hardness, high flexural strength, less porosity and low density has been proposed and study on the effect of different types of phenolic resin on the properties and performance of bipolar plate reveals that novolac type powdered phenolic resin gives better mechanical properties than resole type phenolic resin. However, resole type phenolic resin compound has slightly higher electrical conductivity due to more number of polar -OH group presents on its cured form. But due to the less porosity and higher mechanical strength, bipolar plates with novolac type phenolic resin gives better performance in I-V analysis than bipolar plates with resole type phenolic resin.     

Evaluation of treatment and recovery of leachate by bipolar membrane electrodialysis process

Recovery studies are frequently carried out for electrodialysis (ED) processes. In this study, beyond examining the recovery of leachate components in an electrodialysis process, the use of that process to treat leachate-containing wastewater was simultaneously tested. Leachates were initially pre-treated (ultra filtration + cation exchange) to prevent clogging and harmful effect to the bipolar electrodialysis membranes. Optimum operating conditions were determined at the end of the experimental studies. Online observations during the electrodialysis process included the temperature-dependent reaction time, conductivity and changes of molar concentrations of H⁺ and OH⁻ ions in both the anolyte and catholyte compartments in which removed ions were collected. The most important contaminants in leachates are organic substances and nitrogen compounds. For this reason, representations of organic substances, such as the chemical oxygen demand (COD), and nitrogenous compounds, such as total Kheldahl nitrogen (TKN) and ammonia-nitrogen (NH₃-N), were also monitored in the electrodialysis effluent. Under the optimum operating conditions, removal of NH₃-N, TKN and COD were determined in the effluent at 96.2%, 92.8% and 86.7%, respectively. The conductivity value was determined to be 1.97 mS/cm at the end of the study.     

电化学法清除金属表面垢层的实验研究

介绍采用电化学法清除附着在金属表面附着物的实验情况，论述了电化学法清洗附着在金属表面附着物的原理和方法。实验发现：更换电极极性并突然增大电流密度能获得比较满意的效果，从而为清除金属表面上的结垢、附生物、海藻、海生物等物质提出一个简便易行的方法。     

The characterization and bioelectrocatalytic properties of hemoglobin by direct electrochemistry of DDAB film modified electrodes

Direct electrochemistry of hemoglobin can be performed in acidic and basic aqueous solutions in the pH range 1-13, using stable, electrochemically active films deposited on a didodecyldimethylammonium bromide (DDAB) modified glassy carbon electrode. Films can also be produced on gold, platinum, and transparent semiconductor tin oxide electrodes. Hemoglobin/DDAB films exhibit one, two, and three redox couples when transferred to strong acidic, weak acidic and weak basic, and strong basic aqueous solutions, respectively. These redox couples, and their formal potentials, were found to be pH dependent. An electrochemical quartz crystal microbalance and cyclic voltammetry were used to study the in situ deposition of DDAB on gold disc electrodes and hemoglobin deposition on DDAB film modified electrodes. A hemoglobin/DDAB/GC modified electrode is electrocatalytically reduction active for oxygen and H₂O₂, and electrocatalytically oxidation active for S₂O₄²⁻ through the Fe(III)/Fe(II) redox couple. In the electrocatalytic reduction of S₄O₆²⁻, S₂O₄²⁻, and SO₃²⁻, and the dithio compounds of 2,2′-dithiosalicylic acid and 1,2-dithiolane-3-pentanoic acid, the electrocatalytic current develops from the cathodic peak of the redox couple at a potential of about −0.9 V (from the Fe(II)/Fe(I) redox couple) in neutral and weakly basic aqueous solutions. Hemoglobin/DDAB/GC modified electrodes are electrocatalytically reduction active for trichloroacetic acid in strong acidic buffered aqueous solutions through the Fe(III)/Fe(II) redox couple. However, the electrocatalytic current developed from the cathodic peak of the redox couple at a potential of about −0.9 V (from the Fe(II)/Fe(I) redox couple) in weak acidic and basic aqueous solutions. The electrocatalytic properties were investigated using the rotating ring-disk electrode method.     

Electrochemical generation of narrow conduction electron spin resonance signals in carbon blacks

Electrochemical reduction of either of two different carbon blacks dispersed in methylene chloride gave rise to a temperature independent narrow ESR signal superimposed upon the characteristic broad signal. The observation of this conduction ESR (CESR) signal implies that there are two distinct environments available for charge carriers within the carbon black particles. With the oxidized black, an additional ESR spectrum (g = 2.0034) revealing hyperfine interaction was observed. This was associated with surface oxidized molecules which had been electrochemically reduced and reside in solution as radical anions.     

离子液体在蛋白质电化学中的应用研究

综述了离子液体作为黏合剂、支持电解质和修饰材料这三种功用在氧化还原蛋白质直接电化学中的研究现状,并提出了目前研究存在的问题及此种生物传感器应用前景的展望。     

碳纳米管修饰及在电化学领域的应用

凭借出色的力学、电学性能和化学稳定性,碳纳米管在电化学、纳米器件、能源、催化等领域具有广泛的应用前景。但是,分散性差、化学活性低等缺点极大地限制了碳纳米管的应用。本文主要介绍了了碳纳米管的共价修饰和非共价修饰,分析了各方法的差异和优缺点;并简要介绍了碳纳米管在环境分析、电化学生物传感器等电化学领域的主要应用。     

Direct electrochemistry and electrocatalysis of hemoglobin in lactobionic acid film

Hemoglobin (Hb) embedded in lactobionic acid (LA) film can give a pair of stable, well‐defined, and quasi‐reversible cyclic voltammetric peaks, located at the potential characteristic of the heme Fe(III)/Fe(II) redox couple. The formal potential of the protein in LA film was ?209 mV. The apparent heterogeneous electron transfer rate constant and the number of protons concomitant per electron during the electron transfer process have been calculated. Hydrogen peroxide could also be catalytically reduced by the protein in LA film. Copyright © 2005 Society of Chemical Industry     

电化学方法在常温磷化中的应用研究

对新型磷化方法——电化学磷化进行了探究,采用对工件外加电压的方法对磷化过程进行加速,并获得了优良的磷化效果,证明电化学方法确实有利于磷化过程。通过磷化膜外观评分、磷化膜膜重、硫酸铜点滴时间、3%NaCl浸渍时间4种参数对磷化效果进行评定,初步确定了电化学磷化最佳参数值为:在20℃下,电流密度为7.80~9.00 A/dm2,平均磷化时间为3.8 min,磷化综合评价M值为16.0~17.1。     

电化学预氧化技术在史南站污水处理中的应用

分析了史南站污水热力学稳定性差的原因,并对症采用电化学预氧化技术进行处理,以提高其热力学稳定性,使处理后污水中悬浮固体含量不再随时间的延长而增加,处理后污水的腐蚀速率低(≤0.076 mm/a),污水成分基本不发生变化,与地层水的配伍性好,满足低渗油藏对注入水的要求.该技术的适应性广,可在很宽的pH范围内使用多种絮凝剂将污水处理达标.     

双面粒子的制备及应用研究进展

从聚合物、无机物、聚合物／无机物三方面综述了近年来双面粒子的制备及应用研究进展。