La dissolution de l'anode de cuivre dans les solutions faiblement chlorurées

1983 ◽  
Vol 61 (9) ◽  
pp. 2022-2028 ◽  
Author(s):  
Robert-Louis Brossard
Keyword(s):  
Aqueous Solution ◽  
Chloride Ion ◽  
The Other ◽  
Copper Anode ◽  
Linear Sweep ◽  
Limiting Step ◽  
Dissolution Zone ◽  
Sweep Voltage ◽  
Two Peaks ◽  
Second Wave

The dissolution of a copper anode has been studied in aqueous solution at pH 4 and in which the dissolved LiCl was varied between 0.005 M and 0.1 M. In the dissolution zone, the dissolution valence is unity between 0.03 M and 0.1 M and the step controlling the speed of dissolution is almost entirely attributable to the diffusion of CuCl2− ion in solution for the weakest voltage. The order of reaction with respect to the chloride ion (Cl−) is close to unity for voltage close to the reversible voltage (ECu/CuCl) of the reaction Cu + Cl− = CuCl + 1e, suggesting that diffusion of Cl− ions in solution tends also to become a controlling step when the voltage is close to ECu/CuCl.CuCl appears when the voltage reaches ECu/CuCl, that is when the linear sweep voltage curves show two peaks. These two peaks have the diffusion of ions in the solution as their limiting step. The height of these two peaks is explicable by the diffusion of Cl− ions in solution as the slowest step. On the other hand, the ratio between the peak of the second wave and that of the first is 2.14. This behaviour is in agreement with the fact that the valence of dissolution of copper increases from the first peak to the second. [Journal translation]

Hydrogen Degradation Property of Electrochemically Charged Aluminum

2007 ◽  
Vol 1042 ◽  
Author(s):  
Hiroshi Suzuki ◽  
Daisuke Kobayashi ◽  
Kenichi Takai ◽  
Yukito Hagihara
Keyword(s):  
Aqueous Solution ◽  
Thermal Desorption ◽  
Hydrogen Molecule ◽  
Thermal Desorption Spectroscopy ◽  
Hydrogen Desorption ◽  
The Other ◽  
Hydrogen Degradation ◽  
Hydrogen Recombination ◽  
Free Hydrogen ◽  
Two Peaks

AbstractDegradation property of aluminum due to hydrogen is studied. Hydrogen is introduced by electrolysis charge in aqueous solution with addition of 0.1 mass % NH4SCN as a hydrogen recombination poison. The amount of hydrogen and its existing state in the material is analyzed by hydrogen desorption curves measured by the thermal desorption spectroscopy. The hydrogen desorption curves of charged aluminum showed two peaks, one at less than 100 °C and the other around 400 °C. The existing state of hydrogen relate to each peaks are identified as weakly trapped solute hydrogen to vacancy and free hydrogen molecule located in cavities that exists in the bulk of the material. Tensile properties are obtained to determine degradation property of the material due to hydrogen. The effect of hydrogen on degradation of charged aluminum is analyzed in terms of interaction between hydrogen and vacancy or dislocation. Solute hydrogen and cavities are found to affect ductility of aluminum, whereas hydrogen molecule in cavities has no effect.

Uptake of chloride ion from aqueous solution by calcined layered double hydroxides: Equilibrium and kinetic studies

2006 ◽  
Vol 40 (4) ◽  
pp. 735-743 ◽  
Author(s):  
Liang Lv ◽  
Jing He ◽  
Min Wei ◽  
D.G. Evans ◽  
Xue Duan
Keyword(s):  
Aqueous Solution ◽  
Layered Double Hydroxides ◽  
Chloride Ion ◽  
Kinetic Studies ◽  
Double Hydroxides

The cathodic reduction of PbO in the passive layer on lead in aqueous sulphuric acid

1984 ◽  
Vol 62 (3) ◽  
pp. 596-600 ◽  
Author(s):  
R. G. Barradas ◽  
D. S. Nadezhdin
Keyword(s):  
Experimental Data ◽  
Three Dimensional ◽  
Reference Electrode ◽  
Linear Sweep Voltammetry ◽  
Passive Layer ◽  
Cathodic Reduction ◽  
Linear Sweep ◽  
Current Time ◽  
Lead Monoxide ◽  
Two Peaks

The cathodic reduction of the lead monoxide layer formed on lead in 30% aqueous H2SO4 under anodic oxidation at 0.6 V (vs. Hg/HgSO4 reference electrode) was investigated by linear sweep voltammetry, potential step and admittance measurements. The experimental data were analyzed respectively in terms of thin-layer electrochemistry, electrocrystallisation, and changes of resistance of the PbO layer under reduction. The results seem to be best interpreted from the theory of three-dimensional electrocrystallisation as PbO is reduced to Pb. At sub-zero temperatures the PbO peak observed on our voltammograms and potentiostatic current time transients reveals the splitting of the curves into two peaks, which may be a result of reduction of the same material but of different phases, namely, orthorhombic and tetragonal PbO.

A new three-dimensional anionic cadmium(II) dicyanamide network

2014 ◽  
Vol 70 (11) ◽  
pp. 1054-1056 ◽  
Author(s):  
Qiang Li ◽  
Hui-Ting Wang
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Unit Cell Volume ◽  
Three Dimensional ◽  
Building Blocks ◽  
The Other ◽  
Dimensional Structure ◽  
Cadmium Nitrate ◽  
Nitrate Tetrahydrate ◽  
Anionic Framework

A new cadmium dicyanamide complex, poly[tetramethylphosphonium [μ-chlorido-di-μ-dicyanamido-κ4N1:N5-cadmium(II)]], [(CH3)4P][Cd(NCNCN)2Cl], was synthesized by the reaction of tetramethylphosphonium chloride, cadmium nitrate tetrahydrate and sodium dicyanamide in aqueous solution. In the crystal structure, each CdIIatom is octahedrally coordinated by four terminal N atoms from four anionic dicyanamide (dca) ligands and by two chloride ligands. The dicyanamide ligands play two different roles in the building up of the structure; one role results in the formation of [Cd(dca)Cl]2building blocks, while the other links the building blocks into a three-dimensional structure. The anionic framework exhibits a solvent-accessible void of 673.8 Å3, amounting to 47.44% of the total unit-cell volume. The cavities in the network are occupied by pairs of tetramethylphosphonium cations.

scholarly journals Removal of Chromium from Aqueous Solution Using Modified Pomegranate Peel:Mechanistic and Thermodynamic Studies

2009 ◽  
Vol 6 (s1) ◽  
pp. S153-S158 ◽  
Author(s):  
Tariq S. Najim ◽  
Suhad A. Yassin
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Aqueous Solution ◽  
Adsorption Process ◽  
Batch Process ◽  
The Other ◽  
Water Molecules ◽  
Pomegranate Peel ◽  
Solution Interface ◽  
Adsorbent Surface

Modified pomegranate peel (MPGP) and formaldehyde modified pomegranate peel (FMPGP) were prepared and used as adsorbent for removal of Cr(VI) ions from aqueous solution using batch process. The temperature variation study of adsorption on both adsorbents revealed that the adsorption process is endothermic, from the positive values of ∆H˚. These values lie in the range of physisorption. The negative values of ∆G˚ show the adsorption is favorable and spontaneous. On the other hand, these negative values increases with increase in temperature on both adsorbents, which indicate that the adsorption is preferable at higher temperatures. ∆S˚ values showed that the process is accompanied by increase in disorder and randomness at the solid solution interface due to the reorientation of water molecules and Cr(VI) ions around the adsorbent surface. The endothermic nature of the adsorption was also confirmed from the positive values of activation energy, Ea, the low values of Ea confirm the physisorption mechanism of adsorption. The sticking probability, S*, of Cr(VI) ion on surface of both adsorbents showed that the adsorption is preferable due to low values of S*(0< S*< 1 ), but S*values are lower for FMPGP indicating that the adsorption on FMPGP is more preferable .

Evaluation of dialysis treatment in uremic patients by gel filtration of serum

1990 ◽  
Vol 36 (11) ◽  
pp. 1906-1910 ◽  
Author(s):  
J Osada ◽  
T Gea ◽  
C Sanz ◽  
I Millan ◽  
J Botella
Keyword(s):  
Ion Exchange ◽  
Gel Filtration ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
The Other ◽  
Control Group ◽  
Dialysis Treatment ◽  
Additional Information ◽  
Molecular Masses ◽  
Two Peaks

Abstract A group of substances of molecular masses between 300 and 1500 Da have been found to be toxic metabolites in patients with uremia. We determined the concentration in serum of these molecules in the following groups of patients: two hemodialyzed groups (one with cuprophane and the other with polyacrylonitrile dialyzers), one group treated with continuous ambulatory peritoneal dialysis, one group of nondialyzed azotemic patients, and one control group of healthy persons. Ultrafiltrates of the subjects' sera were fractionated on Sephadex G-15 followed by ion-exchange chromatography. Eluates were monitored by absorbance at 254 and 206 nm. Partially characterized peaks P1 and P2, obtained by gel filtration, correlated with the concentration of creatinine in serum; their concentrations were significantly (P less than 0.01) larger in hemodialyzed groups than in peritoneal dialyzed or in nondialyzed azotemic patients. After ion-exchange chromatography, two peaks (P'5 and P'6) correlated with serum creatinine and also were larger in hemodialyzed patients than in the other groups. Apparently, adequate discrimination is obtained by gel-filtration analysis and further analysis by ion-exchange chromatography does not provide additional information in most of the affected patients.

Dihydropyrimidones based chloride ion chemosensor functional in aqueous solution under environmentally relevant conditions

2017 ◽  
Vol 29 (7) ◽  
pp. 506-517 ◽  
Author(s):  
Amanpreet Kaur ◽  
Ravneet Kaur ◽  
Anil Kuwar ◽  
Narinder Singh ◽  
Navneet Kaur
Keyword(s):  
Aqueous Solution ◽  
Chloride Ion

scholarly journals Linear sweep polarographic determination of nucleic acids using acridine orange as a bioprobe

2007 ◽  
Vol 72 (11) ◽  
pp. 1085-1094 ◽  
Author(s):  
Wei Sun ◽  
Na Zhao ◽  
Xianlong Yuan ◽  
Kui Jiao
Keyword(s):  
Aqueous Solution ◽  
Acridine Orange ◽  
Electrochemical Method ◽  
Electrochemical Determination ◽  
Determination Method ◽  
Linear Regression Equation ◽  
Peak Potential ◽  
Linear Sweep ◽  
Buffer Solution

The interaction of acridine orange (AO) with double-stranded (ds) DNA in aqueous solution was investigated by linear sweep polarography (LSP) on a dropping mercury working electrode (DME). In pH 2.5 Britton-Robinson (B-R) buffer solution, AO had a sensitive linear sweep polarographic reductive peak at -0.89 V (vs. SCE), which could be greatly inhibited by the addition of dsDNA, with a positive shift of the peak potential. Based on the decrease of the reductive peak current, a new quantitative electrochemical determination method for dsDNA was developed with a linear range of 2.0?20.0 mg l-1 and the linear regression equation: ?Ip" (nA) = 111.90 C (mg l-1)+125.32 (n = 9, ? = 0.997). The influences of commonly co-existing substances, such as metal ions, amino acid, etc., on the determination were also investigated. The method is sensitive, rapid and simple with good selectivity. The new proposed method was further applied to the detection of RNA and three synthetic samples containing dsDNA with satisfactory results. The binding number and the equilibrium constant between dsDNA and AO were calculated by an electrochemical method.

scholarly journals Impact of COVID-19 Variants on the Second Wave in India and Subsequent Discretion of Possibilities of the Third Wave

2021 ◽  
pp. 115-126
Author(s):  
Sudarshan Ramaswamy ◽  
Meera Dhuria ◽  
Sumedha M. Joshi ◽  
Deepa H Velankar
Keyword(s):  
Herd Immunity ◽  
Sir Model ◽  
The Other ◽  
Third Wave ◽  
Focal Points ◽  
Current Analysis ◽  
The Third ◽  
The Impact ◽  
Second Wave ◽  
Insight Into

Introduction: Epidemiological comprehension of the COVID-19 situation in India can be of great help in early prediction of any such indications in other countries and possibilities of the third wave in India as well. It is essential to understand the impact of variant strains in the perspective of the rise in daily cases during the second wave – Whether the rise in cases witnessed is due to the reinfections or the surge is dominated by emergence of mutants/variants and reasons for the same. Overall objective of this study is to predict early epidemiological indicators which can potentially lead to COVID-19 third wave in India. Methodology: We analyzed both the first and second waves of COVID-19 in India and using the data of India’s SARS-CoV-2 genomic sequencing, we segregated the impact of the Older Variant (OV) and the other major variants (VOI / VOC).  Applying Kermack–McKendrick SIR model to the segregated data progression of the epidemic in India was plotted in the form of proportion of people infected. An equation to explain herd immunity thresholds was generated and further analyzed to predict the possibilities of the third wave. Results: Considerable difference in ate of progression of the first and second wave was seen. The study also ascertains that the rate of infection spread is higher in Delta variant and is expected to have a higher threshold (>2 times) for herd immunity as compared to the OV. Conclusion: Likelihood of the occurrence of the third wave seems unlikely based on the current analysis of the situation, however the possibilities cannot be ruled out. Understanding the epidemiological details of the first and second wave helped in understanding the focal points responsible for the surge in cases during the second wave and has given further insight into the future.

scholarly journals Decachlorocyclopentasilanes coordinated by pairs of chloride anions, with different cations, but the same solvent molecules

2017 ◽  
Vol 73 (12) ◽  
pp. 1903-1907 ◽  
Author(s):  
Maximilian Moxter ◽  
Julian Teichmann ◽  
Hans-Wolfram Lerner ◽  
Michael Bolte ◽  
Matthias Wagner
Keyword(s):  
Crystal Structures ◽  
General Position ◽  
Rotation Axis ◽  
Chloride Ion ◽  
The Other ◽  
Structural Motif ◽  
Solvent Molecules

We have determined the crystal structures of two decachlorocyclopentasilanes, namely bis(tetra-n-butylammonium) dichloride decachlorocyclopentasilane dichloromethane disolvate, 2C16H36N+·2Cl−·Si5Cl10·2CH2Cl2, (I), and bis(tetraethylammonium) dichloride decachlorocyclopentasilane dichloromethane disolvate, 2C8H20N+·2Cl−·Si5Cl10·2CH2Cl2, (II), both of which crystallize with discrete cations, anions, and solvent molecules. In (I), the complete decachlorocyclopentasilane ring is generated by a crystallographic twofold rotation axis. In (II), one cation is located on a general position and the other two are disordered about centres of inversion. These are the first structures featuring the structural motif of a five-membered cyclopentasilane ring coordinated from both sides by a chloride ion. The extended structures of (I) and (II) feature numerous C—H...Cl interactions. In (II), the N atoms are located on centres of inversion and as a result, the ethylene chains are disordered over equally occupied orientations.

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