scholarly journals Deactivation of poly(o-aminophenol) film electrodes by storage without use in the supporting electrolyte solution and its comparison with other deactivation processes

2015 ◽  
Vol 739 ◽  
pp. 58-65 ◽  
Author(s):  
R. Tucceri
Keyword(s):  
Electrolyte Solution ◽  
Supporting Electrolyte ◽  
Supporting Electrolyte Solution

scholarly journals Cyclic Voltammetry of Auranofin

1999 ◽  
Vol 6 (4-5) ◽  
pp. 233-238 ◽  
Author(s):  
Ahmed A. Mohamed ◽  
Alice E. Bruce ◽  
Mitchell R. M. Bruce
Keyword(s):  
Cyclic Voltammetry ◽  
Electrolyte Solution ◽  
Supporting Electrolyte ◽  
Oxidation Processes ◽  
Irreversible Oxidation ◽  
Thiolate Complexes ◽  
Gold Thiolate ◽  
Oxidative Behavior ◽  
Supporting Electrolyte Solution ◽  
Repeated Cycling

The oxidative behavior of Auranofin, 2,3,4,6-tetra-O-acetyl-1-thio-β -D-glucopyranosato- S(triethylphosphine)gold(I), was investigated by using cyclic voltammetry (CV) in 0.1 M Bu4NPF6/CH2Cl2 and 0.1 M Bu4NPF4/CH2Cl2 solutions using Pt working and auxiliary electrodes and a Ag/AgCI reference. CV studies at scan rates from 50-2,000 mV/s and Auranofin concentrations between 1 and 4 mM, show two irreversible oxidation processes occurring at +1.1 V and +1.6 V vs. Ag/AgCl. Ph3PAu (p-thiocresolate) was also investigated as a reference for comparison of the oxidation processes in Auranofin to that of other phosphine gold thiolate complexes previously reported. The electrochemical response appears to be sensitive to adsorption at the electrode as well as to the nature of the supporting electrolyte solution. Repeated cycling shows a build up of products at the electrode.

The reaction between monosilicic acid and aluminium hydroxide. I. Kinetics of adsorption of silicic acid by aluminium hydroxide

Soil Research ◽  
1967 ◽  
Vol 5 (2) ◽  
pp. 295 ◽  
Author(s):  
FJ Hingston ◽  
M Raupach
Keyword(s):  
Ionic Strength ◽  
Silicic Acid ◽  
Electrolyte Solution ◽  
Aluminium Hydroxide ◽  
Solid Phase ◽  
Supporting Electrolyte ◽  
Kcal Mole ◽  
Monosilicic Acid ◽  
Kinetics Of ◽  
Supporting Electrolyte Solution

Studies of the reaction between monosilicic acid and crystalline aluminium hydroxide showed that a number of layers of silicic acid could be formed on the surface of the hydroxide. Silicate is considered to be adsorbed as silicic acid rather than as silicate ions. The first layer was produced by rapid reaction of silicic acid with the surface of aluminium hydroxide. The isotherm for this initial reaction was not affected by varying the temperature from 10 to 35�C or by increasing the ionic strength of the supporting electrolyte solution. Adsorption of silicic acid resulted in increased KOH uptake by (or H2SO4 displacement from) the solid phase, which corresponded to a decrease in pH of the suspension. Subsequent layer formation was slower; the rate increased both with increasing temperature and with the ionic strength of the supporting electrolyte solution. Study of the kinetics of the reaction showed that these layers could have formed by polymerization of silicic acid on the hydroxide surface. The activation energy for the reaction increased with increasing surface coverage from 15 to 24 kcal/mole for the second layer and was about 24 kcal/mole for the third layer.

scholarly journals Colloidal stability and aggregation of lignocellulosic materials in aqueous suspension: A review

BioResources ◽  
2008 ◽  
Vol 3 (4) ◽  
pp. 1419-1491 ◽  
Keyword(s):  
Colloidal Stability ◽  
Aqueous Suspension ◽  
Supporting Electrolyte ◽  
Double Layers ◽  
Lignocellulosic Materials ◽  
Wood Extractive ◽  
Charged Surfaces ◽  
Salt Ions ◽  
Aqueous Conditions ◽  
Supporting Electrolyte Solution

Aqueous dispersions of lignocellulosic materials are used in such fields as papermaking, pharmaceuticals, and preparation of cellulose-based composites. The present review article considers published literature dealing with the ability of cellulosic particle dispersions (fiber, fines, nanorods, etc.) to either remain well dispersed or to agglomerate in response to changes in the composition of the supporting electrolyte solution. In many respects, the colloidal stability and coagulation of lignocellulosics can be understood in terms of well-known concepts, including effects due to osmotic pressure arising from overlapping electrostatic double layers at the charged surfaces. Details of the morphology and surface properties of lignocellulosic materials give rise to a variety of colloidal behaviors that make them unique. Adjustments in aqueous conditions, including the pH, salt ions (type and valence), polymers (charged or uncharged), and surfactants can be used to control the dispersion stability of cellulose, lignin, or wood-extractive materials to serve a variety of applications.

Adsorption and Oxidation of Thiosulfate on a Platinum Electrode in Acid Solution

1998 ◽  
Vol 63 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Tomáš Loučka
Keyword(s):  
Open Circuit Potential ◽  
Platinum Electrode ◽  
Supporting Electrolyte ◽  
Open Circuit ◽  
Adsorbed Layers ◽  
Adsorbed Substance ◽  
Adsorbed Sulfur ◽  
Adsorption Desorption ◽  
Supporting Electrolyte Solution ◽  
Thiosulfate Concentration

The adsorption of thiosulfate on a platinum electrode was measured at the open circuit potential. A monolayer of the adsorption products covers the electrode at lower thiosulfate concentrations. The charge used up during the reduction of the monolayer roughly corresponds to 0.5 electron per surface site (e.p.s.), the charge used up during the oxidation of the monolayer after reduction corresponds approximately to 4 e.p.s. Multiple adsorbed layers, which are presumably constituted mainly by adsorbed sulfur, build up at higher thiosulfate concentrations. The amount of the adsorbed substance increases with increasing thiosulfate concentration and time of adsorption. Desorption from the surface coated by multiple layers can take place in supporting electrolyte solution. The build-up of multiple adsorbed sulfur layers also takes place during adsorption from solutions of colloidal sulfur.

scholarly journals Influence of supporting electrolyte on electrochemical formation of copper nanoparticles and their electrocatalytic properties

2021 ◽  
Author(s):  
Silvana García ◽  
Noelia Zurita
Keyword(s):  
Copper Nanoparticles ◽  
Electrolyte Solution ◽  
Particle Density ◽  
Supporting Electrolyte ◽  
Pyrolytic Graphite ◽  
Electrolyte Solutions ◽  
Reduction Reaction ◽  
Three Solutions ◽  
Sem Images ◽  
Size Dispersion

Comparative analysis of copper nanoparticles (CuNPs) obtained by electrodeposition on highly oriented pyrolytic graphite (HOPG) substrates from different supporting electrolytes containing sulphate anions, was performed. Voltammetric results indicated that Cu electrodeposition follows a diffusion-controlled nucleation and crystal growth model for three solutions studied (Na2SO4, H2SO4 and Na2SO4+H2SO4). Na2SO4 solution was found to be most effective because the copper reduction occurs at most positive potential value, reaching the highest current density. Analysis of potentiostatic current transients revealed that the process can be described predominantly by a model involving 3D-progressive nucleation mechanism, which was corroborated by scanning electron microscopy (SEM) analysis. SEM images showed high density of hemispherical shaped Cu particles of different sizes (mostly between 80-150 nm), randomly distributed on the HOPG surface for Na2SO4 electrolyte solution. In the presence of H2SO4, the size dispersion decreased, resulting in particles with greater diameters (up to 339 nm). The use of electrolyte solution with Na2SO4+H2SO4 revealed lower particle density with a considerable crystal size dispersion, where very small crystallites are prevailing. Cyclic voltammetry was used to evaluate qualitatively the catalytic activity of CuNPs deposited from three electrolyte solutions towards the nitrate reduction reaction. An enhanced catalytic effect was obtained when copper particles were prepared from either Na2SO4 or H2SO4 supporting electrolytes.

scholarly journals Electrochemical oxidation and electroanalysis of paracetamol on a boron-doped diamond anode material in aqueous electrolytes

2021 ◽  
Author(s):  
Kouakou Etienne Kouadio ◽  
Ollo Kambiré ◽  
Konan Sylvestre Koffi ◽  
Lassine Ouattara
Keyword(s):  
Electrolyte Solution ◽  
Current Density ◽  
Supporting Electrolyte ◽  
Current Intensity ◽  
Applied Current ◽  
Boron Doped Diamond ◽  
Preparative Electrolysis ◽  
Applied Current Density ◽  
Bdd Electrode ◽  
Boron Doped

Electrochemical oxidation of paracetamol on boron-doped diamond (BDD) anode has been studied by cyclic voltammetry and preparative electrolysis. Quantification of paracetamol during electrolysis has been mainly realized by differential pulse voltammetry technique in the Britton-Robinson buffer solutions used as the supporting electrolyte. Various parameters such as current intensity, nature of the supporting electrolyte, temperature, and initial concentration of paracetamol have been investigated. The electrochemical characterization by the outer sphere Fe(III)/Fe(II) redox couple has also been performed, showing the metallic character of BDD electrode. The obtained linear dependency of the oxidation peak current intensity and paracetamol concentration indicates that BDD electrode can be used as an electrochemical sensor for the detection and quantification of paracetamol. The investi­gation of paracetamol degradation during preparative electrolysis showed that: (i) the degradation rate of paracetamol increases with increase of current intensity applied; (ii) for the initial concentrations of 10, 6 and 1 mM of paracetamol, its oxidation rate reaches 60, 78 and 99 % respectively, after 1 h of electrolysis in 0.3 M H2SO4 (pH 0.6) at applied current density of 70 mA cm-2; (iii) at temperatures of electrolyte solution of 28, 55 and 75 °C, paracetamol oxidation rate reached 85, 92 and 97 % respectively, after 2 h at applied current density of 70 mA cm2. From the investigation of the effect of pH value of electrolyte solution, it appears that oxidation of paracetamol is more favorable in acidic solution at pH 3 than solutions of higher pH values.

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