Electrochemical Behaviour of Zink Electrode in an Neutral Environment at Polarization with Industrial Alternating Current

2013 ◽  
Vol 781-784 ◽  
pp. 367-371
Author(s):  
S.S. Bitursyn ◽  
A.B. Bayeshov ◽  
M. Sarbaeva
Keyword(s):  
Current Efficiency ◽  
Current Density ◽  
Electrolyte Concentration ◽  
Electrochemical Behaviour ◽  
Alternating Current ◽  
Sodium Sulphate ◽  
Zinc Compounds ◽  
Titanium Electrode ◽  
Electrochemical Technology ◽  
Zinc Dissolution

The article deals with the process of electrochemical dissolution of zinc polarization by alternating current of 50 Hz frequency in a solution of sodium sulfate. The influence of various parameters on the current efficiency of zinc dissolution was considered: the current density on the titanium and zinc electrodes, electrolyte concentration, duration of electrolysis and temperature of electrolyte. It was shown that at change of current density on the titanium electrode from 10 kA/m2 up to 70 kA/m2 current efficiency of zinc dissolution increases (55%), and further down. At change of current density of zinc electrode from 200 A/m2 to 800 A/m2, electrolysis time from 0.25 to 2.0 hours and increase of temperature from 20°C to 80°C the current efficiency of dissolution decreases and with increasing concentrations of sodium sulphate increases to 90%. Based on the results shown it is possible to create a waste-free synthesis of zinc compounds from environmental harmful residues of zinc metal by electrochemical technology.

scholarly journals ELECTROCHEMICAL BEHAVIOR OF CUPRONICKEL ELECTRODE IN ACIDIC MEDIA

2021 ◽  
pp. 38-46
Author(s):  
R. N. Nurdillayeva ◽  
N. Sh. Abdilda ◽  
A. B. Bayeshov
Keyword(s):  
Aqueous Solution ◽  
Hydrochloric Acid ◽  
Current Efficiency ◽  
Current Density ◽  
Kinetic Method ◽  
Alternating Current ◽  
Solution Temperature ◽  
Cycle Duration ◽  
Half Cycle ◽  
Titanium Electrode

The electrochemical properties of the cupronickel electrode polarized by an alternating current in an aqueous solution of hydrochloric acid were studied for the first time. The electrochemical dissolution of cupronickel was carried out in a polarization mode with a frequency of 50 Hz in pairs with a titanium electrode. The current efficiency of dissolution of Cu-Ni alloys dependence on the current density at the titanium (20-120 kA/m2) and cupronickel (200-1200 A/m2) electrodes, the concentration of a hydrochloric acid solution (0.5-5.0 M), the electrolysis duration (0.5-1.75 h) and the alternating current effect (50-300 Hz) were considered. It was observed that the current efficiency of the alloy dissolution decreases linearly with increasing current density at the cupronickel electrode, while the current density at the titanium electrode passes through a maximum value at 60 kA/m2. The dependence of the alloy dissolution on the acid concentration was studied, and the reaction order was calculated. The reaction orders for the formation of copper (I) and nickel (II) ions accounted for 0.95 and 0.85, respectively. As the frequency of the alternating current increased, the current efficiency of the cupronickel electrode dissolution changed significantly. It has been shown that high current frequencies do not provide the required anodic half-cycle duration for the oxidation reaction of the metals, as the periods change very rapidly. It was found that electrolysis is effective at a frequency of 50 Hz AC. It was observed that the dissolution rate of the copper-nickel alloy increases with increasing solution temperature. It was found that the dissolution of cupronickel in an aqueous solution of hydrochloric acid by the temperature-kinetic method takes place in the diffusion-kinetic mode. Ideally, the current efficiency values were 59% for Cu (I) ions and 15% for Ni (II) ions.

scholarly journals Study on the effect of electrocatalytic oxidation treatment of 2,4,6-Trinitrophenol wastewater

2018 ◽  
Vol 238 ◽  
pp. 03003
Author(s):  
Yaling Li ◽  
Wenqiang Jiang ◽  
Ruyu Li
Keyword(s):  
Current Density ◽  
Electrocatalytic Oxidation ◽  
Electrolyte Concentration ◽  
Removal Rate ◽  
Pharmaceutical Chemical ◽  
Oxidation Treatment ◽  
Titanium Electrode ◽  
First Order Kinetics ◽  
Oxidation Technology ◽  
Aromatic Nitro

2,4,6-Trinitrophenol is a toxic aromatic nitro-compounds that widely used in pharmaceutical, chemical and pesticide production. Due to its stable structure and poor biodegradability, advanced electrocatalytic oxidation technology was selected to treat simulated wastewater. The goal of the present work is to optimize the electrolysis conditions such as current density, electrolysis pH, and electrolyte concentration. A Pt modified TiO2 electrode was chosen as the anode accompanied with a titanium electrode of the same size as the cathode The results showed that the removal efficiency of 2,4,6-Trinitrophenol was the highest when the current density was 20mA/cm2, electrolyte pH=5, electrolyte concentration was 2 g/L. Under the optimal condition, the removal rate of 2,4,6-Trinitrophenol reached 99.76% after 120 minutes electrolysis. The decay of TNP could also be described by the pseudo-first-order kinetics formula with respect to TNP concentration. Therefore, electrocatalytic oxidation technology might provide an effective method for the degradation of nitroaromatic organic compounds.

scholarly journals ELECTROCHEMICAL BEHAVIOR OF SILVER IN A SULPHURIC ACID SOLUTION

2020 ◽  
Vol 6 (444) ◽  
pp. 30-37
Author(s):  
A. B. Baeshov ◽  
◽  
E. Zh. Tuleshova ◽  
A. K. Baeshova ◽  
M. A. Ozler ◽  
...  
Keyword(s):  
Alternating Current ◽  
Sulphuric Acid Solution ◽  
Electrochemical Process ◽  
Silver Electrode ◽  
Half Period ◽  
Distinctive Features ◽  
Titanium Electrode ◽  
Electrochemical Processes ◽  
Electrochemical Technology ◽  
Rate Of Dissolution

In recent years, alternating current has been widely used in various fields of chemical and electrochemical technology. When a symmetric alternating current passes through an electrochemical cell, in principle there should be no visible changes, since the product restored to the cathode half-period should be oxidized back to the anodic half-period. However, depending on the conditions of electrolysis, electrode material, etc. a purposeful course of the electrochemical process is possible. The paper shows the distinctive features of electrochemical processes occurring on a silver electrode during electrolysis by industrial alternating current in a solution of sulfuric acid by the method of rational mathematical planning. The optimal conditions for the dissolution of silver are determined by studying the effect of current density at the electrodes, the concentration and temperature of the electrolyte, the duration of the electrolysis and the frequency of the alternating current. It is shown that when polarized with an alternating current of silver in a pair with a titanium electrode, the process of passivation of the silver electrode is eliminated, and the rate of dissolution of the metal increases.

Study on Special Morphology Hydroxyapatite Bioactive Coating by Electrochemical Deposition

2013 ◽  
Vol 537 ◽  
pp. 256-260
Author(s):  
Cai Ge Gu ◽  
Qian Gang Fu ◽  
He Jun Li ◽  
Jin Hua Lu ◽  
Lei Lei Zhang
Keyword(s):  
Electrochemical Deposition ◽  
Current Density ◽  
Electrolyte Concentration ◽  
Spherical Particles ◽  
Constant Current ◽  
Constant Current Density ◽  
Depth Direction ◽  
Special Morphology ◽  
Calcium Phosphate Coatings ◽  
Coating Weight

Bioactive calcium phosphate coatings were deposited on carbon/carbon（C/C） composites using electrochemical deposition technique. The effects of electrolyte concentration and constant current density on morphology, structure and composition of the coating were systematically investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. The results show that, the coating weight elevated gradually with the increase of electrolyte concentration, and the morphology of coatings changed from spherical particles to nanolamellar crystals with interlocking structure initially. Then the coating transformed into seaweed-like and nano/micro-sized crystals along the depth direction of the coating. The coatings showed seaweed-like morphology as the deposition current density was less than 20mA. With the less current density, the coating became more homogenous. However, the coating was fiakiness crysal, with needlike crystal stacked upside as the current density reached to 20mA/cm2. The coating weight was improved gradually when the current density increased from 2.5mA/cm2 to 10mA/cm2, then reduced with the increasing current density in the range of 10 to 20mA/cm2.

Optimization for white organic light-emitting diode based on DCJTB as color conversion layer

2018 ◽  
Vol 32 (27) ◽  
pp. 1850299
Author(s):  
Pei Wang ◽  
Zhen Wang ◽  
Ai Chen ◽  
Jia-Feng Xie ◽  
Xin Zheng
Keyword(s):  
Current Efficiency ◽  
Current Density ◽  
White Light ◽  
Power Efficiency ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
High Efficient ◽  
Color Conversion

In this paper, combining phosphorescence and fluorescence to form white light was realized based on DCJTB:PMMA/ITO/NPB/TCTA/FIrpic:TCTA/TPBi/Ir(ppy)3:TPBi/TPBi/Cs2CO3/Al. The effects of red fluorescence on this white light device was studied by adjusting the concentration of DCJTB. The study shows that the device with a DCJTB concentration of 0.7% in the color conversion layer (CCL) generates a peak current efficiency and power efficiency of 23.4 cd ⋅ A[Formula: see text] and 7.5 lm ⋅ W[Formula: see text], respectively. And it is closest to the equal-energy white point of (0.33, 0.33) which shows a CIE (Commission Internationale de L’Eclairage) coordinate of (0.35, 0.43) and a color rendering index (CRI) of 70 at current density of 10 mA ⋅ cm[Formula: see text]. In order to improve the efficiency, we design and fabricate both high efficient and pure white organic light-emitting diode (WOLED) by replacing the single blue emission layer (EML) with double EMLs of FIrpic:TCTA and FIrpic:TPBi. The further study shows that, when the layers of EML is three and the concentration of DCJTB at 0.7%, the device exhibits good performance specifically, at current density of 10 mA ⋅ cm[Formula: see text], the current efficiency of 28.2 cd ⋅ A[Formula: see text] (power efficiency of 10.3 lm ⋅ W[Formula: see text]), and the CIE coordinate of (0.33, 0.31) (CRI of 80.38).

scholarly journals Investigation of NiFe-Based Catalysts for Oxygen Evolution in Anion-Exchange Membrane Electrolysis

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1720
Author(s):  
Sabrina Campagna Zignani ◽  
Massimiliano Lo Faro ◽  
Stefano Trocino ◽  
Antonino Salvatore Aricò
Keyword(s):  
Single Cell ◽  
Anion Exchange ◽  
Oxygen Evolution ◽  
Current Density ◽  
Electrochemical Behaviour ◽  
Stress Test ◽  
Supporting Electrolyte ◽  
Anion Exchange Membrane ◽  
Operating Conditions ◽  
Exchange Membrane

NiFe electrodes are developed for the oxygen evolution reaction (OER) in an alkaline electrolyser based on an anion exchange membrane (AEM) separator and fed with diluted KOH solution as supporting electrolyte. This study reports on the electrochemical behaviour of two different NiFe-oxide compositions (i.e., Ni1Fe1-oxide and Ni1Fe2-oxide) prepared by the oxalate method. These catalysts are assessed for single-cell operation in an MEA including a Sustainion™ anion-exchange membrane. The electrochemical polarization shows a current density of 650 mA cm−2 at 2 V and 50 °C for the Ni1Fe1 anode composition. A durability test of 500 h is carried out using potential cycling as an accelerated stress-test. This shows a decrease in current density of 150 mA cm−2 mainly during the first 400 h. The performance achieved for the anion-exchange membrane electrolyser single-cell based on the NiFeOx catalyst appears promising. However, further improvements are required to enhance the stability under these operating conditions.

scholarly journals The study of Zn–Co alloy coatings electrochemically deposited by pulse current

2012 ◽  
Vol 66 (5) ◽  
pp. 749-757 ◽  
Author(s):  
Jelena Bajat ◽  
Miodrag Maksimovic ◽  
Milorad Tomic ◽  
Miomir Pavlovic
Keyword(s):  
Surface Roughness ◽  
Current Efficiency ◽  
Direct Current ◽  
Current Density ◽  
Pulse Current ◽  
Pulse Plating ◽  
Cathodic Current ◽  
Average Current Density ◽  
Corrosion Stability ◽  
Average Current

The electrochemical deposition by pulse current of Zn-Co alloy coatings on steel was examined, with the aim to find out whether pulse plating could produce alloys that could offer a better corrosion protection. The influence of on-time and the average current density on the cathodic current efficiency, coating morphology, surface roughness and corrosion stability in 3% NaCl was examined. At the same Ton/Toff ratio the current efficiency was insignificantly smaller for deposition at higher average current density. It was shown that, depending on the on-time, pulse plating could produce more homogenous alloy coatings with finer morphology, as compared to deposits obtained by direct current. The surface roughness was the greatest for Zn-Co alloy coatings deposited with direct current, as compared with alloy coatings deposited with pulse current, for both examined average current densities. It was also shown that Zn-Co alloy coatings deposited by pulse current could increase the corrosion stability of Zn-Co alloy coatings on steel. Namely, alloy coatings deposited with pulse current showed higher corrosion stability, as compared with alloy coatings deposited with direct current, for almost all examined cathodic times, Ton. Alloy coatings deposited at higher average current density showed greater corrosion stability as compared with coatings deposited by pulse current at smaller average current density. It was shown that deposits obtained with pulse current and cathodic time of 10 ms had the poorest corrosion stability, for both investigated average deposition current density. Among all investigated alloy coatings the highest corrosion stability was obtained for Zn-Co alloy coatings deposited with pulsed current at higher average current density (jav = 4 A dm-2).

scholarly journals Dissolution of iron in sodium chloride solution during alternating current polarization

2021 ◽  
Vol 318 (3) ◽  
pp. 51-62
Author(s):  
A. Bayeshova ◽  
◽  
A. Bayeshov ◽  
A. Kadirbayeva ◽  
F. Zhumabay ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Iron Hydroxide ◽  
Alternating Current ◽  
Iron Electrode ◽  
Half Cycle ◽  
Iron Compounds ◽  
Titanium Electrode ◽  
Sodium Chloride Solutions ◽  
Multi Stage ◽  
First Time

Iron compounds are widely used in many industries and engineering, and even in medicine. The existing methods of obtaining iron compounds are multi-stage and complex. The purpose of this work is to obtain iron (II) hydroxide and oxide from metal waste under alternating current action using one and two half-cycles. For the first time, the electrochemical behavior of iron electrode was studied by electrolysis method during alternating current polarization of industrial frequency in sodium chloride solutions. The iron polarization was carried out in pair with titanium, while the current density on the iron electrode varied in the range of 200-1200 A/m2, and on the titanium is in the range of 20-100 kA/m2. It is established that in the anode half-cycle of alternating current, iron is oxidized to form divalent ions. At this moment, the titanium electrode is in the cathode half-cycle, hydrogen is released on it, hydroxyl ions are formed in the cathode space. In the solution, ions interact with iron (II) ions to produce iron hydroxide. At temperatures above 600C, iron (II) hydroxide is dehydrated with the production of iron (II) oxide. The electrolysis was carried out in two electrolyzers connected to each other in parallel with the immersion of pair of “titanium-iron” electrodes into each electrolyzer. The iron dissolution occurs simultaneously in two half-cycles of alternating current and this approach is proposed for the first time. The process productivity increases by more than 1.5 times.

The Application and Research of Electrochemical Method Treating Acid Red 3R Simulation Wastewater by Response Surface Method

2013 ◽  
Vol 295-298 ◽  
pp. 1258-1262
Author(s):  
Jun Sheng Hu ◽  
Lei Guan ◽  
Jia Li Dong ◽  
Ying Wang ◽  
Ying Yong Duan
Keyword(s):  
Response Surface ◽  
Electrochemical Oxidation ◽  
Current Density ◽  
Electrochemical Method ◽  
Electrolyte Concentration ◽  
Ph Value ◽  
Removal Rate ◽  
Oxidation Method ◽  
Surface Method ◽  
Optimal Value

Using electrochemical oxidation method treats the acid red 3R simulation wastewater, investigates the influence of current density, electrolyte concentration, pH-value and aeration and their interaction on the removal rate of chroma. Through the design of Box-Benhnken Design(BBD) and the response surface analysis, the influence sequence of all variables is current density > aeration > electrolyte concentration > pH-value, the influence sequence of all interaction is electrolyte concentration-aeration > current density-aeration ,electrolyte concentration-pH value > current density-pH value > pH value-aeration > current density-electrolyte concentration. Ultimately, the optimal value is 98.4915% under the condition of current density of 6.51mA/cm2,electrolyte concentration of 0.04mol/L,pH-value of 4.17 and aeration of 0.24m3/h.

Sign in / Sign up

Export Citation Format

Share Document