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.

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 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.

Extraction of Tin (Sn) from Solder Dross by Using Hydrochloric Acid Leaching Treatment

2015 ◽  
Vol 754-755 ◽  
pp. 567-570
Author(s):  
Syarifah Aminah Ismail ◽  
Noorina Hidayu Jamil ◽  
Kamarudin Hussin ◽  
Mohd Arif Anuar Mohd Salleh
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Hydrochloric Acid ◽  
Acid Concentration ◽  
Acid Leaching ◽  
Experimental Results ◽  
Solution Temperature ◽  
Hydrochloric Acid Leaching ◽  
Stirring Time ◽  
Acid Aqueous Solution

This project deals with the experimental results of leaching of Sn from solder dross by means of leaching using different concentration of hydrochloric acid (HCl). Solder dross was sieved to obtain a mean particle size of 75 μm. The solder dross powder obtained was leached by using HCl acid aqueous solution. To optimize the parameter required for recovery of Sn from solder dross, initially the bench scale studies were carried out using varying acid concentration, stirring time and temperature. The experimental indicate that 98.7% of Sn was leached out from solder dross using 0.1M of HCl, 24 hours of stirring time at60°C solution temperature.

Electrochemical dechlorination of 2,4-dichlorophenol in aqueous solution on palladium-loaded meshed titanium electrode

2011 ◽  
Vol 63 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Z. R. Sun ◽  
M. Gao ◽  
Y. Z. Peng ◽  
X. Hu
Keyword(s):  
Aqueous Solution ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Ambient Temperature ◽  
Current Efficiency ◽  
Removal Efficiency ◽  
Experimental Results ◽  
Titanium Electrode ◽  
Scanning Electron ◽  
Supporting Electrode

Electrochemical dechlorination of 2,4-dichlorophenol (2,4-DCP) in aqueous solution was investigated on palladium-loaded meshed titanium (Pd/Ti) electrode at ambient temperature. Pd/Ti electrode was prepared with an electrodepositing method. Scanning Electron Microscope (SEM) micrographs show that Pd microparticles uniformly disperse on the meshed Ti supporting electrode with spheroidal structure. Dechlorination experimental results indicate that, in aqueous solution, with the current efficiency of 24.3%, the removal efficiency of 100 mg/L 2,4-DCP on Pd/Ti electrode was 93.2% under the conditions of the dechlorination current of 5 mA and dechlorination time of 90 min. The effect of initial 2,4-DCP concentration was also investigated.

scholarly journals DISSOLUTION OF STAINLESS STEEL IN SODIUM CHLORIDE SOLUTION AT POLARIZATION BY NON-STATIONARY CURRENT

2021 ◽  
Vol 447 (3) ◽  
pp. 75-81
Author(s):  
R.N. Nurdillayeva ◽  
Zh.G. Sauirbay ◽  
A.B. Bayeshov
Keyword(s):  
Stainless Steel ◽  
Current Efficiency ◽  
Alternating Current ◽  
Dissolution Behavior ◽  
Stainless Steel Electrode ◽  
Half Cycle ◽  
Electrochemical Dissolution ◽  
Steel Electrode ◽  
Current Frequency ◽  
Steel Electrodes

Stainless steel is in great demand due to its mechanical strength, heat resistance, and resistance to corrosive environments. This article presents the result of a study of the electrochemical dissolution behavior of a stainless steel electrode (12X18H10T) at polarization by 50 Hz alternating current in a neutral medium (NaCl). Preliminary experiments have shown that the main processes do not take place when two stainless steel electrodes are polarized with an alternating current. It was observed that by the polarization of the “stainless steel – titanium” pair electrodes with alternating current, the alloy is intensively dissolved with the formation of iron (II) and chromium (III) ions. This is due to the "valve" properties of the oxide layer formed on the surface of the titanium electrode. A change in the value of the current density of the titanium and steel electrodes significantly affects the process of electrochemical dissolution of the alloy. At high current densities, the dissolution rate of the alloy decreases due to the deterioration of the current correcting properties of titanium. With an increase in the electrolyte concentration, the current efficiency is reduced as salt passivation occurs. A maximum value of the current efficiency of dissolution of stainless steel was observed at a current frequency of 50 Hz. High frequencies of the alternating current do not provide an adjustable duration of the anodic half-cycle for the oxidation reaction due to the frequent change of halfcycles of the alternating current. It was observed that increasing the temperature of the electrolyte reduces the current efficiency of the electrochemical dissolution of stainless steel electrodes. The effects of main electrochemical parameters on the electrolysis process have been investigated, and the optimal conditions of the alloy dissolution were established (іТі = 60 kA/m2 , іSS = 800 A/m2 , [NaCl] = 2.0 M, t = 30, ν = 50 Hz.).

scholarly journals Electrochemical Degradation of Reactive Red 195 from its Aqueous Solution using RuO2/IrO2/TaO2 Coated Titanium Electrodes

2021 ◽  
Vol 33 (8) ◽  
pp. 1919-1922
Author(s):  
M. Umadevi ◽  
R. Rathinam ◽  
S. Poornima ◽  
T. Santhi ◽  
S. Pattabhi
Keyword(s):  
Aqueous Solution ◽  
Current Density ◽  
Operating Conditions ◽  
Optimum Operating ◽  
M Current ◽  
Titanium Electrode ◽  
Treatment Techniques ◽  
Nacl Concentration ◽  
Cell Reactor ◽  
Reactive Red 195

The electrochemical oxidation of reactive red 195 from aqueous solution was carried out using titanium electrode in an electrochemical cell reactor. The effect of different operating parameters such as dye concentration, current density, electrolyte concentration, pH and stirring speed were investigated. The UV-visible spectroscopy confirmed the removal and degradation of reactive red 195. Three different supporting electrolytes such as NaCl, NaNO3 and Na2SO4 were used for electrolysis and NaCl were found to be effective for the removal of reactive red 195 dye from its aqueous solution. The maximum percentage of colour removal was 94%, under the optimum operating conditions with electrolyte (NaCl) concentration 0.075 M, current density 25 mA/cm2, pH 5 and stirring speed of 250 rpm. This method was found to be relatively more effective to the conventional treatment techniques.

Studying dispersed and rheological properties of hydrocarbon-containing acid emulsions and their efficiency in removing asphalt-resin-paraffin deposits

2020 ◽  
pp. 128-139
Author(s):  
M. Yu. Shumakher ◽  
V. V. Konovalov ◽  
A. P. Melnikov
Keyword(s):  
Aqueous Solution ◽  
Hydrochloric Acid ◽  
Rheological Properties ◽  
Reaction Rate ◽  
Experimental Studies ◽  
Efficient Removal ◽  
Reservoir Properties ◽  
Hydrocarbon Solvents ◽  
Formation Zone ◽  
Effect Of The Composition

Currently, the treatment of the bottomhole formation zone with acidic compositions is one of the most common methods to intensify the oil inflow. The use of various modified acid compositions increases the efficiency of acid treatments on the bottomhole formation zone. Acid compositions, including those containing hydrocarbon solvents, which contribute to more efficient removal of organic colmatants, affect the reaction rate of the reagent with the rock and processing equipment, change the reservoir properties, etc.The article presents the results of experimental studies, which are aimed at establishing the effect of the composition of hydrocarbon-containing acidic emulsions consisting of an aqueous solution of hydrochloric acid, toluene and Neonol AF 9-10 on their dispersed and rheological properties, as well as their efficiency in removing paraffin deposits.

Formation of Barrier Oxide Film on Lead in Borate Solutions

1994 ◽  
Vol 59 (6) ◽  
pp. 1305-1310 ◽  
Author(s):  
Emad E. Abdel Aal ◽  
Mohamed M. Hefny
Keyword(s):  
Oxide Film ◽  
Current Density ◽  
High Field ◽  
Empirical Relation ◽  
Field Approximation ◽  
Ion Concentration ◽  
Solution Temperature ◽  
Oxide Growth ◽  
Rate Of Growth ◽  
Barrier Type

Galvanostatic anodization of lead in borate solutions reveals that lead can form a barrier type oxide film. The rate of growth, R, fulfils the empirical relation, R = aib within the current density i range from 1.16 .10-4 to 3.19 .10-4 A cm-2. The magnitudes of the parameters a and b are 6.9 . 103 and 1.6, respectively, it has been found that the high field approximation is applicable for the oxide growth on lead. The coefficients of the dependence of R on solution temperature, T, pH and borate ion concentration, c, viz. (∂R/∂T), (∂R/∂pH) and (∂R/∂log c) are -18 . 10-4, -0.13 and 0.41, respectively.

scholarly journals Thermo-Responsive Behavior of Mixed Aqueous Solution of Hydrophilic Polymer with Pendant Phosphorylcholine Group and Poly(Acrylic Acid)

Polymers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 148
Author(s):  
Hirokazu Fukumoto ◽  
Kazuhiko Ishihara ◽  
Shin-Ichi Yusa
Keyword(s):  
Aqueous Solution ◽  
Acrylic Acid ◽  
Solution Temperature ◽  
Interpolymer Complex ◽  
Mixed Aqueous Solution ◽  
Upper Critical Solution Temperature ◽  
Acidic Conditions ◽  
Decreasing Ph ◽  
Increasing Temperature ◽  
Poly Acrylic Acid

A mixed aqueous solution of hydrophilic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and poly(acrylic acid) (PAAc) becomes cloudy under acidic conditions at room temperature. The pendant carboxylic acid groups in PAAc form hydrogen bonds with the ester and phosphate groups in PMPC. While the polymers aggregate under acidic conditions, neither one associate under basic conditions because of the deprotonation of the pendant carboxy groups in PAAc. We observed that the interpolymer complex formed from PMPC, and PAAc was dissociated in aqueous solutions with increasing temperature, which is an upper critical solution temperature behavior. With increasing temperature, the molecular motion increased to dissociate the interpolymer complex. The phase transition temperature increased with increasing polymer and salt concentrations, and with decreasing pH.

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