Real time observation of the anodic dissolution of copper in NaCl solution with the digital holography

There are three possible cases of the initial electro-dissolution reactions of bare copper in acid/neutral chloride media. Two of them involve the direct formation of a cuprous chloride species from the metal, while the other, the dissolution of copper as cuprous ion. In the present work, the digital holography has been employed with an attempt to identify the actual mechanism through observing the dynamic changes of the diffusion layer at the electrode/electrolyte interface during the anodic processes of copper in 0.5 mol dm^?3 NaCl solution. On the basis of the phase distribution reconstructed from the holograms, the dynamic changes of concentration field within the diffusion layer of the process can be obtained. The results confirm that, at the initial stage, the cuprous ion is formed first, which then reacts to produce the cuprous chloride and/or cuprous chloride complexes.     

Macromolecule-Metal Complexes for Gas Separation

Macromolecule-copper(I) chloride complexes have been prepared for the separation of carbon monoxide and ethylene from gas mixtures with hydrogen, nitrogen, carbon dioxide, methane, and water. A toluene solution of a polystyrene-aluminum copper(I) chloride complex can separate carbon monoxide selectively and retains this function even on contact with gas containing water. Strong charge-transfer absorption bands have been found in the 380-500 nm region for the toluene solution of polystyrene-aluminum copper(I) chloride complex. A solution of 1, 3-diphenylpropane-aluminum copper(I) chloride complex also exhibits similar absorption bands. A continuous variation plot using the chemical shift change in ¹³C-NMR shows a 1:1 interaction between 1,3-diphenylpropane and aluminum copper(I) chloride. These results suggest a two-way interaction between the adjacent phenyl groups of polystyrene and aluminum copper(I) chloride. A resin bead of crosslinked polystyrene-aluminum copper(I) chloride complex has been prepared as a solid adsorbent. The water resistance of the solid macromolecular complex depends on the nature of the solvent used in the preparation of the solid adsorbent. Carbon disulfide is a suitable solvent. A selective adsorbent of ethylene has been prepared from a macroreticular polystyrene resin with primary and secondary amino groups and copper(I) chloride. The selectivity of ethylene against ethane and that of carbon monoxide against carbon dioxide increase with an increasing amount of supported copper(I) chloride.     

Effect of anion adsorption on early stages of copper electrocrystallization at Au(111) surface

The monolayer and submonolayer deposition of copper on Au(111) electrode surface in the presence of chloride and sulfate ions was studied by in situ X-ray absorption and electrochemical techniques. The anions coadsorb with the deposited copper adatoms and have a strong influence on the structure of these mixed overlayers. Copper deposited in the presence of chloride forms a bilayer in which copper atoms are sandwiched between the gold substrate and the top layer of chloride ions. The bilayer is well ordered and has a (5×5) long range structure. The copper atoms are packed in registry with the top layer of chloride ions. In contrast, copper adatoms deposited in the presence of sulfate ions are packed in registry with respect to the Au(111) substrate. The coadsorbed copper and sulfate form a highly corrugated overlayer. The copper adatoms assume a honeycomb (√3×√3) structure with the center of the honeycomb occupied by sulfate. The sulfate ion adsorbs with three of its four oxygens directed towards the hexagon of copper adatoms. The bond angle between the copper adatom and the oxygen of the sulfate ion is approximately equal to 45 °. Our data indicate that, in contrary to the literature reports, the (√3×√3) structure observed on STM and AFM images corresponds to the corrugation of adsorbed sulfate ions rather than copper adatoms.     

Traveling fronts of copper deposition

We report the experimental observation of traveling fronts during the electroless deposition of copper on passive steel substrates. The low-carbon steel samples are passivated in nitric acid prior to the plating experiment, thus creating a thin, protective oxide layer on the steel surface. The deposition experiments are carried out from slightly acidic (pH 3.2) copper sulfate solution and copper nitrate solution with the latter showing front propagation only in the presence of chloride ions. For up to 30 s, fronts propagate with constant velocities in the range from 0.5 to 5 mm/s depending on the experimental conditions. This phase of constant-speed propagation gives way to accelerating fronts and very rapid, spatially unstructured deposition. Front-mediated plating is observed over a wide range of cupric ion concentration and constitutes a striking and unexpected example for pattern formation in electrochemical systems.     

Continuous biotreatment of copper-concentrated solutions by biosorption with Sargassum sp.

Seaweed Sargassum sp. biomass proved to be useful for the recovery of ionic copper from highly concentrated solutions simulating effluents from semiconductor production. In the case of solutions containing copper in the form of chloride, sulfate, and nitrate salts, the best pH for the recovery of copper was 4.5. It was observed that copper biosorption from copper nitrate solutions was higher than the recovery of copper from copper chloride or copper sulfate solutions. The continuous system used was constituted of four column reactors filled with the biomass of Sargassum sp. and showed high operational stability. The biomass of Sargassum sp. in the reactors was gradually saturated from the bottom to the top of each column reactor. The biomass of Sargassum sp. in the first column saturated first, followed by a gradual saturation of the remaining columns owing to preconcentration performed by the biomass in the first column. The biomass of Sargassum in the bioreactors completely biosorbed the ionic copper contained in 63 L of copper sulfate solution, 72 L of copper chloride solution, and 72 L of copper nitrate solution, all the solutions containing copper at 500 mg/L. Effluents produced after biosorption presented copper concentrations < 0.5 mg/L.     

1-甲基-3丁基咪唑氯离子液体中片状硫化铜纳米结构研究

以1-甲基-3丁基咪唑氯离子液体为溶剂直接溶解氯化铜,硫化钠水溶液作为沉淀剂快速制得片状硫化铜纳米颗粒.对比实验揭示,离子液体对于片状硫化铜纳米结构的形成具有决定性的影响.UV-Vis光谱检测显示其在240到600 nm处有较宽的吸收峰.     

Chlorination of copper-containing raw material by ammonium chloride

A new method of processing the copper-containing raw material to copper(II) oxide was suggested and examined based on the chlorination of copper-containing raw material with ammonium chloride followed by dissolution of copper chloride, precipitation of copper hydroxide from a solution and its calcining to copper(II) oxide. Thermogravimetric analysis of the process was conducted. Kinetics of chlorination of copper(II) oxide by ammonium chloride was experimentally investigated. Technological scheme of the copper-containing raw material processing with ammonium chloride was suggested.     

Zeolite ZSM-5 containing copper ions: The effect of the copper salt anion and NH<Subscript>4</Subscript>OH/Cu<Superscript>2+</Superscript> ratio on the state of the copper ions and on the reactivity of the zeolite in DeNO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>

Isotherms of copper cation sorption by H-ZSM-5 zeolite from aqueous and aqueous ammonia solutions of copper acetate, chloride, nitrate, and sulfate are considered in terms of Langmuir’s monomolecular adsorption model. Using UV-Vis diffuse reflectance spectroscopy, IR spectroscopy, and temperatureprogrammed reduction with hydrogen and carbon monoxide, it has been demonstrated that the electronic state of the copper ions is determined by the ion exchange and heat treatment conditions. The state of the copper ions has an effect on the redox properties and reactivity of the Cu-ZSM-5 catalysts in the selective catalytic reduction (SCR) of NO with propane and in N₂O decomposition. The amount of Cu²⁺ that is sorbed by zeolite H-ZSM-5 from aqueous solution and is stabilized as isolated Cu²⁺ cations in cationexchange sites of the zeolite depends largely on the copper salt anion. The quantity of Cu(II) cations sorbed from aqueous solutions of copper salts of strong acids is smaller than the quantity of the same cations sorbed from the copper acetate solution. When copper chloride or sulfate is used, the zeolite is modified by the chloride or sulfate anion. Because of the presence of these anions, the redox properties and nitrogen oxides removal (DeNO _x ) efficiency of the Cu-ZSM-5 catalysts prepared using the copper salts of strong acids are worse than the same characteristics of the sample prepared using the copper acetate solution. The addition of ammonia to the aqueous solutions of copper salts diminishes the copper salt anion effect on the amount of Cu(II) sorbed from these solutions and hampers the nonspecific sorption of anions on the zeolite surface. As a consequence, the redox and DeNO _x properties of Cu-ZSM-5 depend considerably on the NH₄OH/Cu²⁺ ratio in the solution used in ion exchange. The aqueous ammonia solutions of the copper salts with NH₄OH/Cu²⁺ = 6–10 stabilize, in the Cu-ZSM-5 structure, Cu²⁺ ions bonded with extraframework oxygen, which are more active in DeNO _x than isolated Cu²⁺ ions (which form at NH4OH/Cu2+ = 30) or nanosized CuO particles (which form at NH₄OH/Cu²⁺ = 3).     

Identification of Different Copper Green Pigments in Renaissance Paintings by Cluster-TOF-SIMS Imaging Analysis

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging using cluster primary ion beams is used for the identification of a green painting layer on the scene The Angels Concert from the Issenheim Altarpiece (painted in 1516) from a German Renaissance painter, Matthias Grünewald. Copper carboxylate clusters inside a basic copper chloride (atacamite) layer have been identified and located in the copper green layer. The mechanisms of transformation of atacamite into copper carboxylates may be initiated by an aging of the paint layers. The combination of the high mass resolution of the technique together with a micrometer spatial resolution and the possibility to simultaneously identify both minerals and organics, has proven to be the method of choice for the study of the stratigraphy of a paint cross-section.     

Regeneration by Membrane Electrolysis of an Etching Solution Based on Copper Chloride

Regeneration of an acid solution for copper etching, based on copper(II) chloride, hydrochloric acid, and ammonium chloride, by membrane electrolysis was studied. The concentrations of copper(I, II) ions in the cathode and anode spaces, current efficiency, degree of copper recovery, and specific consumption of electric power at different quantities of electricity passed through the electrolyzer were measured. The influence exerted by the current density on the electric power expenditure for recovery of metallic copper was examined. The anode current efficiency by chlorine was determined with a spent etching solution and an H₂SO₄ solution used as anolyte.     

Electrocatalysis of copper deposition from acid sulphate solutions by sulphite and selenite ions

The effects of traces of chloride, sulphur, selenium and tellurium dioxide and the selenate and tellurate ions on the electrodeposition of copper from acid copper sulphate have been studied. Low concentrations of chloride have little effect on deposition kinetics but concentrations up to 20 ppm significantly affect nodule formation. Sulphur dioxide and selenium dioxide are true electrocatalysts for deposition, with SeO₂ the more effective. Molecules in solution immediately adjacent to the electrode appear to be the active catalyst. The catalytic mechanism may be a reduction oxidation cycle involving the elements in unstable forms. The chloride ion is adsorbed according to a Langmuir type isotherm. Adsorbed chloride inhibits catalysis by SO₂ and SeO₂. The electrocatalysts have been used to demonstrate the effect of overpotential on the structure of copper deposited at constant current density.     

Copper Corrosion in Acid Chloride Solutions: A Quartz Microgravimetry Study

Making use of the quartz microgravimetry method allows one to in situ obtain the m vs. t curves simultaneously with the E _cor vs. t curves (m is the weight of a dissolved or deposited substance, t a time period, E _cor a corrosion potential), which gives one a chance to determine the corrosion rate and its dependence on the concentration of copper ions and chloride ions in solution to within a good accuracy. The corrosion rate increases with increasing concentration of ions of divalent copper in solution, while an increase in the concentration of chloride ions does not lead to its change. The formation of a salt film of an intermediate compound of univalent copper during the copper dissolution process in solutions diluted with respect to chloride ions (0.1 M NaCl, 0.03 M CuCl₂) is discovered experimentally. In the m vs. t curves, the formation of the film manifests itself in the form of an increase in the electrode weight, while the corrosion potential transients reflect but weakly the occurring complex surface conversions. Techniques for the identification of intermediate solid species are proposed. The coefficients of mass transfer with respect to ions of divalent copper are determined. Explanations for variations in the system's behavior following a decrease in the concentration of chloride ions in solution are offered.     

Application of FT-Raman spectroscopy to the study of the benzotriazole inhibition of acid copper corrosion

The initial stages of the corrosion protection of copper surfaces by benzotriazole in sulfuric acid solution are investigated using FT-Raman SERS and X-ray photoelectron spectroscopy. Spectra are measured in the presence of ppm levels of inhibitor on a copper surface in situ. The dependence of the adsorbate spectra on the electrode potential, solution pH, oxidation/reduction cycles and time is observed. Good spectra are obtained from copper electrodes prepared using in situ oxidation/reduction cycling in low pH sulfate solutions free from chloride at negative potentials.     

基于氯化胆碱离子液体的铜电沉积研究（英文）

采用恒电流和恒电位方法,基于含有氯化铜溶液的乙二醇-氯化胆碱或硫脲-氯化胆碱离子液体,室温下在钢阴极上进行了铜的电沉积. 利用扫描电子显微镜和X-射线衍射技术研究了各种实验条件对电沉积的影响以及沉积层的形貌. 结果表明,室温下施加不超过-0.45 V的沉积电位和不超过-4.0 A·m^-2的沉积电流密度,可以同时从氯化胆碱基乙二醇和硫脲离子液体中沉积得到非常光滑、有光泽、致密且具有良好结合力、色泽鲜艳的铜金属涂层. 铜的电沉积阴极电流效率约为97%.     

Copper ion-selective chalcogenide glass electrodes: Analytical characteristics and sensing mechanism

New copper ion-selective electrodes based on chalcogenide glasses, Cu_xAg_25?xAs_37.5Se_37.5, display high copper(II) ion sensitivity with Nernstian response in the range pCu 1–6, short response time, high selectivity, potential stability and reproducibility. These electrodes are 10–30 times more sensitive in strongly acidic media than crystalline copper ion-selective sensors and are superior to the copper(I) selenide electrode in selectivity and resistance to acids and oxidation. A model is proposed to explain the ion sensitivity of these chalcogenide glass sensors. The sensitivity depends on direct exchange of copper(II) ions between solution and the modified surface layer of the glass. The modified surface layer is formed as a result of partial destruction of the glass network on soaking in solution; its atomic density is 2.0–2.5 times less than that of the original glass. The structural defects and hollows make fast copper(II) ion migration within the modified surface layer possible. Exchange sites in this layer can be formed by both disproportionation and oxidation of copper(I) in the glass network, as well as by diffusion of copper(II) ion from solution in the case of glasses with low copper content. Experimental confirmation of this model is provided by x-ray, photo-electron and scanning Auger electron spectroscopy.     

Polymerization of vinylcarbazole on copper(II)-13X molecular sieves: Role of copper(II) salts

Copper(II)-exchanged-13X molecular sieves, prepared from four copper(II) salts, namely, sulfate, nitrate, chloride, and acetate, and their activities in the polymerization of N-vinylcarbazole at a fixed copper ion exchange level were studied. From the kinetic characteristics of polymerization it was established that the variation in activities of the Cu-exchanged sieves is due primarily to the difference in the pH of the original salt solution, which is responsible for the varying degree of proton exchange with the zeolite during copper ion exchange. A first-order dependence of the rate of polymerization was observed with respect to H⁺ ion concentration of the original copper-salt solution. It was further established that the rate of polymerization of exchanged copper ion, at a hypothetical zero proton concentration, is low. A mechanism of polymerization of NVC on copper-exchanged-13X zeolite was suggested on the basis of the results obtained.     

Low-potential amperometric determination of purine derivatives through surface oxide regeneration method

This article described a novel amperometry which can be used for determination of purine derivatives including uric acid, xanthine, hypoxanthine, guanine, and adenine without surface contamination. By applying a constant potential of −0.125 V (vs. Ag/AgCl) in a flow injection system, the chelating capability of these purine derivatives converts the cuprous oxide layer into a soluble complex. This behavior would dissolve the passive oxide layer and expose the bottom copper layer to the solution, subsequently; an oxidation current which attributed to the regeneration of the original cuprous oxide layer is used to reflect the concentration of these purine derivatives. In a 50 mM phosphate buffer, pH 7.0, this approach provides a high sensitivity with LOQ of sub-micro molar level of five purines and high stability with a RSD of 2.5% for 10 μM xanthine (N = 12). This method does not suffer from most biological species including ascorbic acid, acetaminophen, creatine, dopamine, sarcosine, ammonium ion, chloride ion, and urea at equal or higher than its physiological concentration.     

Scanning Tunnelling Microscopy Study of Chloride Adsorbed on Cu(110) Surfaces in Hydrochloric Acid Solution

Fundamental studies of the interaction of chloride with copper is of great interest from both scientific and technological view points since it is related to the copper electroplating and also the halogen etching processes^[1]. In this paper, in-situ scanning tunneling microscopy (STM) has been employed to study chloride adsorption on Cu(110) electrode in hydrochloride acid aqueous solution. The atomic resolution images of chloride adsorbed on Cu(111) surface have been obtained over the potential range from -400 mV to -100 mV (vs. SCE). A (l×l) structure for Cu(110) substrate was observed at the potential negative than -450 mV in which the chloride anions are desorbed. Our results indicate that the chloride anions are very strongly adsorbed on the Cu(110) surface at the potential positive than -400 mV. The images taken over a large region show parallel rows on the terraces and monolayer straight steps, which run along the[001] direction of the substrate lattice. The parallel row structures observed here are suggested to attribute from the chloride adlayers. The different corrugation height and periodical modulation in the height along[110] direction observed indicates that chloride anions are located at physically non-equivalent binding sites. Models are proposed to interpret the structures with three-fold periodicity and four-fold periodicity along[110] direction with a (4×1) structure containing three chloride anions and a (5×1) structure containing four chloride anions, respectively.     

Über die Kupferelektrolyse

Irregularities during the electrolytic deposition of copper are caused by varying concentrations of traces of chloride ions. Bromide develops a cathodic adsorption layer, which facilitates the copper deposition. Addition of urea is without any effect.     

氯离子对铜在玻碳电极上电结晶的影响

采用线性扫描伏安法和计时安培法研究了硫酸铜溶液中铜在玻碳电极上电结晶 的初期行为。在含与不含氯离子的0.05mol·L~(-1) cUso_4-0.5 mol·L~(-1) H_2SO_4电解液中,循环伏安实验结果表明铜在玻碳基体上的沉积没有经过UPD过 程;氯离子明显使Cu的沉积和氧化峰变得尖锐,促进Cu的沉积速度。计时安培实验 结果表明,Cu的电结晶按瞬时成核和三维生长方式进行。氯离子不改变Cu的结晶机 理,但在I～t曲线中,导致电流达最大(I_m)所需的时间t_m减小、晶核数密度和生 长速度增大,从而明显改变Cu沉积层的质量。当Cl~-浓度在10～20mg·L~(-1)范围 内,成核的晶核数密度达较大,即氯离子的最适宜添加量。