Soluble Anode Research Articles

Electrochemical copper deposition from an ethaline-CuCl2·2H2O DES

Cu electroplating was carried out using a pure ethaline melt, a 1:2 ratio of choline chloride and ethylene glycol, at room temperature by potentiostatic and galvanostatic methods. Hydrated cupric chloride was added to the pure ethaline melt. Polarisation data for cupric ion reduction to copper was collected using an RDE to determine where metal deposition was feasible. Smooth Cu deposits were obtained at −4.7×10−3A/cm2 using 0.2M CuCl2·2H2O at 25°C at a current efficiency of (95±5)% at a rotation speed of 700rpm. XRD analysis of the deposit showed a polycrystalline face centred cubic structure with (111) texture. The crystalline size was 66±10nm with some internal strain. EDX analysis showed the presence of carbon and chlorine with copper in the deposit, which was due to the break-down of the DES. Several deposition processes were carried out from a single bath to examine bath stability. The bath was found to be stable when a soluble anode was employed, and became unstable when an insoluble anode was used due to other reactions proceeding at the cathode.

Synthesis of layered metal dichalcogenides with organic cations by electrochemical reduction in suspensions

Intercalated group IVB-VIB metal disulfides and diselenides MX2 (M = Ti, Zr, Nb, Mo) can be obtained by electrochemical reduction of the corresponding MX2 in the presence of tetraalkylammonium salt. An original approach was used, which allowed effective reduction of these insoluble substances in the form of powders suspended in an organic solvent using the standard electrolysis technique in solutions in a one-space electrolyzer with a soluble anode. Using electron transfer mediators in the process afforded intercalated compounds with yields of 60–100%.

Galvanic Production Waste Water Treatment with Electro/coagulation Sludge in Terms of Nickel and Copper Ions

A possibility of nickel ions and copper ions recovery from galvanic waste waters with electro-coagulation sludge that is formed in the process of electro/chemical cleaning of galvanic drainage pipes with the use of soluble aluminum anodes has been demonstrated. Nickel ions recovery from the galvanic waste water in case of the optimal proportion of the sludge has reached at least 55 %.

Through-Hole Filling in a Cu Plating Bath with Functional Insoluble Anodes and Acetic Acid as a Supporting Electrolyte

Through-hole (TH) filling of a printed circuit board (PCB) was conducted with a copper electroplating solution. Tetranitroblue tetrazolium chloride (TNBT) was used as an inhibitor and acetic acid electrolyte instead of a traditional H2SO4 electrolyte was used for the copper electroplating. Moreover, functional insoluble anodes (DT) that were activated with iridium-based mixed metal oxides on Ti meshes were used instead of conventional soluble anodes (i.e., P-doped Cu). The TH filling performance of the copper electroplating solution was significantly enhanced when acetic acid electrolyte and DT anodes were used simultaneously in the copper electroplating bath.

Behavior of Soluble and Insoluble Anodes in Cu Electroplating

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Improved corrosion resistance of brush plated nanocrystalline Ni–Fe alloy coatings in 3·5 wt‐%NaCl solution

Nanocrystalline Ni and Ni–Fe alloy coatings were synthesised by brush plating using soluble anode, and the corrosion characteristics of nanocrystalline Ni, Ni–5·84%Fe and Ni–13·49%Fe were investigated by soak method and electrochemical polarisation method respectively. The nanocrystalline Ni–Fe alloy coatings showed higher hardness and smaller grain size than that of Ni coating. Ni–13·49%Fe alloy coating exhibited better corrosion resistance in 3·5 wt‐% NaCl solution than the nanocrystalline Ni coating and the Ni–5·84%Fe coating, which indicats that the corrosion resistant of nanocrystalline Ni coating can be improved by adding appropriate amount of Fe.

Electrocoagulation–electroflotation as a surface water treatment for industrial uses

Water is a natural product that is needed in many industrial uses, but some processes like washing or cooling do not require drinking water. In this work we investigated the efficiency of an electrolytic treatment of surface waters in order to increase their quality. The waters were taken from a river and in a pond and they were treated by electrocoagulation–electroflotation with an aluminum soluble anode. Vital nutriments for the bacteria development were consumed during the electrolysis. This treatment led to great decreases of molecular oxygen, phosphate and nitrate anions and dissolved organic compounds. Each of these decreases may explain the disinfection effect that was observed for the total flora. Moreover, the X-ray diffraction of the electro-generated solid showed the presence of nanocrystallites that could be involved in a bactericidal effect. After the electrocoagulation–electroflotation treatment, the investigated waters exhibited an increased quality for a cooling use.

전기응집/부상 공정을 이용한 TiO2폐수의 탁도 제거

The separation of wastewater carried out by an electrocoagulation/flotation process, which had various operating parameters. The effect of electrode material (aluminum and four dimensionally stable electrode), applied current (0.07~0.5 A), electrolyte concentration (0~1 g/L), solution pH (3~11), initial turbidity (1000~20000 NTU) and suspended solid concentration (5000~25000 mg/L) were evaluated. Turbidity removal efficiency of the soluble anode (aluminum), which could produce metal ions, was higher than that of the dimensionally stable electrode. Considering operation time, turbidity removal and electric power, optimum current was 0.19 A. The more NaCl dosage was high, the less electric power was required. However, optimum NaCl concentration was 0.125 g/L considered removal efficiency, operation time and cost. Initial concentration did not affected turbidity removal on the electrocoagulation/flotation operation. The electrocoagulation/flotation process was proved to be a very effective separation method in the removal of from wastewater.

Treatment of dairy effluents by electrocoagulation using aluminium electrodes

This work sets out to examine the efficiency of an electrolytic treatment: electrocoagulation, applied to dairy effluents. The experiments were carried out using a soluble aluminium anode on artificial wastewater derived from solutions of milk powder. The flocks generated during this treatment were separated by filtration. The analysis of the filtrates showed that the chemical oxygen demand (COD) was reduced by up to 61% while the removal of phosphorus, nitrogen contents, and turbidity were 89, 81 and 100%, respectively. An analogous treatment applied to phosphate and lactose solutions revealed that lactose was not eliminated, a fact that could account for the rather poor lowering of the COD. Compared to the chemical coagulation treatment with aluminium sulphate, the efficiency of the electrocoagulation technique was almost identical. However the wastewaters treated by electrocoagulation differed by the fact that they exhibited a lower conductivity and a neutral pH value (by contrast to the acid nature of the solution treated by the chemical coagulation). This result (low conductivity, neutral pH) tends to show that it may be possible to recycle the treated water for some industrial uses. Moreover, the electrocoagulation process uses fewer reagents: the mass of the aluminium anode dissolved during the treatment is lower compared to the quantity of the aluminium salt used in chemical coagulation. These two observations clearly show that the electrocoagulation technique is more performing.

Rational use of soluble anodes

The use of soluble copper anodes in the brass plating of wire is optimized. The selection of material for insoluble anodes is considered.

Treatment of textile wastewater by a hybrid electrocoagulation/nanofiltration process

Untreated effluents from textile industries are usually highly coloured and contain a considerable amount of contaminants and pollutants. Stringent environmental regulation for the control of textile effluents is enforced in several countries. Previous studies showed that many techniques have been used for the treatment of textile wastewater, such as adsorption, biological treatment, oxidation, coagulation and/or flocculation, among them coagulation is one of the most commonly used techniques. Electrocoagulation is a process consisting in creating metallic hydroxide flocks within the wastewater by the electrodissolution of soluble anodes, usually made of iron or aluminium. This method has been practiced for most of the 20th century with limited success. In recent years, however, it started to regain importance with the progress of the electrochemical processes and the increase in environmental restrictions in effluent wastewater. This paper examines the use of electrocoagulation treatment process followed by nanofiltration process of a textile effluent sample. The electrocoagulation process was studied under several conditions such as various current densities and effect of experimental tense. Efficiencies of COD and turbidity reductions and colour removal were studied for each experiment. The electrochemical treatment was indented primarily to remove colour and COD of wastewater while nanofiltration was used to further improve the removal efficiency of the colour, COD, conductivity, alkalinity and total dissolved solids (TDS). The experimental results, throughout the present study, have indicated that electrocoagulation treatment followed by nanofiltration processes were very effective and were capable of elevating quality of the treated textile wastewater effluent.

Electroreduction of alkylphenones in diaphragmless cell with soluble anode

Electroreduction of alkylphenones Ph-CO-(CH2)2R, where R = CH3-, C2H5-, C4H9-, allows the corresponding diols of the general composition [R(CH2)2-PhC(OH)-PhC(OH)-(CH2)2R] to be synthesized. This process was carried out in 0.2 M Et4NBr solution in dimethylformamide under the conditions of diaphragmless galvanostatic electrolysis with a Pt cathode and a Mg (Zn) anode at a current of 0.2 A and a temperature of 30°C. Optimization of this process makes it possible to synthesize a mixture of meso/dl isomers of target products (the meso/dl ratio depends on the R size and varies from 1/0.30 to 1/0.08) with the overall yields of 31–62% per the loaded ketone for its conversion by 52–86%.

On-line Electrogeneration of Copper–Peptide Complexes in Microspray Mass Spectrometry

The interaction of copper ions with peptides was investigated by electrospray mass spectrometry. Two electrospray micro-emitters were compared, the first one with a platinum electrode using a copper(II) electrolyte solution containing a peptide sample, and the second one with a sacrificial copper anode in a water/methanol solution containing only a peptide (i.e., angiotensin III, bradykinin, or Leu-enkephalin). The former yielded mainly Cu(2+) complexes either with histidine residues or with the peptide backbone (Cu(+) complexes can be also formed due to gas-phase reactions), whereas the latter can generate a mixture of both Cu(+) and Cu(2+) aqueous complexes that yield different complexation patterns. This study shows that electrospray emitters with soluble copper anodes enable the study of Cu(I)-peptide complexes in solution.

Electrochemical synthesis of Cu-containing polyheteroarylenes and study of their catalytic properties

Method of electrochemical synthesis of new Cu-containing polyheteroarylenes that have biquinolyl units in their main chain is developed on the base of the soluble anode technique. The study of electrochemical properties of thus obtained Cu-containing polymer and the corresponding monomer complex revealed existence of two types of coordination environment: (1) copper Cu(I) in the tetrahedral surrounding of two biquinolyl ligands and (2) copper Cu(I) bound with only one biquinolyl fragment. The complexes with one biquinolyl polymer ligand showed high activity as catalysts for O2 reduction in the presence of hydroquinone that is converted to quinone in the course of the reaction.

Morphology of a dispersed tellurium electrochemical deposition in aprotic solvents

The electrolysis of TeCl4 solutions in dimethylsulfoxide, dimethylformamide and acetonitrile using soluble tellurium anodes has been investigated. At 313 K in 0.05 M TeCl4 over graphic undercoat the formation of compact tellurium deposit took place at cathode potentials less than 1.0 V and formation of dispersed deposit – at values more than 1.25-1.5 V. Using results of SEM researches it was established that dispersed tellurium formed

Anode materials and processes occurring in palladium–nickel electrolyte

The behaviour of various inert and soluble anode materials has been studied in a weakly acidic chloride electrolyte for deposition of Pd–Ni alloys. Inert anodes studied were graphite, and platinum, while the soluble ones were palladium and nickel. The possible preparation of a combined Pd–Ni anode is examined. The processes occurring on the anode are identified. The evolution of chlorine and oxygen is considered to be undesirable. The effects of the anode material, pH and temperature on the rate of chlorine and oxygen evolution have been studied by recording the polarisation curves under potentio-dynamic regime as a function of potential scan rate. The most suitable anode materials prove to be platinum and ruthenium oxide (OPTA). The use of combined Pd–Ni anodes is not recommended, since a third undesirable reaction also occurs on these, that of oxidation of ethylenediamine. Methods for elimination of the undesirable, side anode processes are proposed with a view to improving stable operation of the electrolyte.

Influence of the Anode on the Degradation of the Additives in the Damascene Process for Copper Deposition

The influence of both soluble and insoluble anodes on the kinetics and morphology of the copper deposit in the damascene process was investigated by voltammetry and impedance techniques. A plating bath known to provide conformal superfilling of trenches and vias in the microelectronic industry was used. It was shown that the use of a glassy carbon anode leads to faster degradation of the plating bath which is detrimental to the copper deposit. A copper anode decreases the aging rate by limiting the anodic potential compared to the glassy carbon anode where high anodic potentials prevail during the copper deposition process.

An alternative method for the removal of surfactants from water: Electrochemical coagulation

Feasibility of the removal of surfactants from model solution and the polluted water sample by electrochemical coagulation utilizing Fe 2+ ions from a soluble anode as an alternative method was investigated in this study. As a result of the studies the removal of surfactant having a concentration of 10 mg L −1 has been achieved with an efficiency of 100%. Experiments were conducted to examine the effects of applied current density, initial concentration, supporting electrolyte concentration, coagulant dosage and pH on the removal efficiency. Energy consumption was calculated for each experiment and optimum conditions have been determined. Addition of ferrous sulphate and hydrogen peroxide was seen to enhance the efficiency of the process. The polarity of the reactor played an important role in the treatment of surfactants. Electrochemical coagulation of the water sample from a local stream has also been conducted in high efficiencies. The results suggest that electrochemical coagulation is a promising method for the treatment of water polluted by detergents.

Electrocarboxylation of Carbon Tetrachloride in Dimethylformamide with Use of a Soluble Zinc Anode

Regularities of electrochemical carboxylation of carbon tetrachloride in conditions of galvanostatic diaphragmless electrolysis with a soluble zinc anode are studied. It is established that the generation of the CCl 3 − anion at the cathode is accompanied by the discharge of salts of Zn2+, with the deposition of Zn0 at the surface. The interaction between and CCl 3 − and CO2 in experimental conditions leads to the formation of zinc trichloromethylacetate, which proves to be very unstable in the dimethylformamide environment and undergoes fragmentation with the CO2 evolution. It is found that this process competes with currentless reduction of trichloromethylacetate under the action of Zn0 deposited on the cathode surface. As a result, corresponding dichloromethylacetate with a small yield of ≤5.5% forms as the sole product of electrolysis.

Electroplating of zirconium and aluminum hydroxide thin films following anodic dissolution of corresponding metal anodes in organic medium

Zirconium (IV) hydroxide or hydrate oxide films, which are typically difficult to prepare by electrochemical methods using aqueous solutions, are easily fabricated in an acetone bath using Zr anodes as the metal sources and a metal-free solvent containing halide ions as the supporting electrolyte. This method is also confirmed to be applicable to aluminum anodes. In the early stage of electrolysis, anodic oxidation of the metal anode proceeds in the presence of water as an impurity in the solvent. Subsequently, pitting corrosion of the oxide film on the metal anode occurs as a result of the action of halide ions. The corrosiveness of the halogen additive appears to be an important factor determining the dissolution or deposition of metal species in this stage. That is, Br− is more active for electrochemical dissolution of a passive oxide film on the anode compared to I−. Finally, Zr species are deposited on the cathode surface via reactions with cathodically generated hydroxide ions. In these processes, the metal plate acts as a soluble anode and as a metal source for electrodeposition. The coating of Zr (IV) hydroxide film on a stainless steel substrate is shown to act as an effective barrier against electrolytic corrosion.