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.

Comparative investigation on the removal of methyl orange from aqueous solution using three different advanced oxidation processes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zahia Benredjem ◽  
Karima Barbari ◽  
Imene Chaabna ◽  
Samia Saaidia ◽  
Abdelhak Djemel ◽  
...  
Keyword(s):  
Methyl Orange ◽  
Current Density ◽  
Advanced Oxidation Processes ◽  
Degradation Rate ◽  
Supporting Electrolyte ◽  
Advanced Oxidation ◽  
Comparative Investigation ◽  
Oxidation Processes ◽  
The Comparative Study ◽  
Kinetics Of

Abstract The Advanced Oxidation Processes (AOPs) are promising environmentally friendly technologies for the treatment of wastewater containing organic pollutants in general and particularly dyes. The aim of this work is to determine which of the AOP processes based on the Fenton reaction is more effective in degrading the methyl orange (MO) dye. The comparative study of the Fenton, photo-Fenton (PF) and electro-Fenton (EF) processes has shown that electro-Fenton is the most efficient method for oxidizing Methyl Orange. The evolution of organic matter degradation was followed by absorbance (discoloration) and COD (mineralization) measurements. The kinetics of the MO degradation by the electro-Fenton process is very rapid and the OM degradation rate reached 90.87% after 5 min. The influence of some parameters such as the concentration of the catalyst (Fe (II)), the concentration of MO, the current density, the nature and the concentration of supporting electrolyte was investigated. The results showed that the degradation rate increases with the increase in the applied current density and the concentration of the supporting electrolyte. The study of the concentration effect on the rate degradation revealed optimal values for the concentrations 2.10−5 M and 75 mg L−1 of Fe (II) and MO respectively.

scholarly journals Nucleation/Growth and Optical Proprieties of Co-doped ZnO Electrodeposited on ITO Substrate

2021 ◽  
Vol 12 (5) ◽  
pp. 6776-6787
Keyword(s):  
Cyclic Voltammetry ◽  
Growth Mechanism ◽  
Supporting Electrolyte ◽  
Saturated Calomel Electrode ◽  
Nucleation And Growth ◽  
Visible Range ◽  
Zno Films ◽  
Doped Zno ◽  
Nucleation And Growth Mechanism ◽  
Co Doped

A Co-doped ZnO layer was prepared by electrodeposition method on indium doped tin oxide (ITO) substrate using a cathodic reduction from nitrate medium with different doping percentages of cobalt. The bath temperature was controlled at 70 °C. The films were cathodically electrodeposited in a bath containing 5 mM Zn(NO3)2. 6H2O, while the source of Co is Co(NO3)2.6H2O where 0.1M KNO3 was used as supporting electrolyte. The nucleation and growth mechanism of Co-doped ZnO nuclei have been studied by cyclic voltammetry and chronoamperometry. The cyclic voltammetry shows that the electrodeposition of ZnO and Co-doped ZnO at a negative potential around -1.0 V versus saturated calomel electrode (SCE) is a quasi-reversible reaction controlled by the diffusion process. Comparing current transients curves obtained by the chronoamperometric method with the theoretical curves of current density j versus t ½ allows us to say that the nucleation is 3D instantaneous, as shown in SEM analysis. The presence of Co does not modify the nucleation and growth mechanism. The XRD patterns show that the substitution of zinc by cobalt does not change the würtzite crystal structure, but the crystallite size decreases with the cobalt percentage. The transmittance spectra indicate that the Co-doped ZnO films are transparent in the visible range. The optical gap increases with the doping percentage of cobalt.

scholarly journals Effects of State of Charge on the Physical Characteristics of V(IV)/V(V) Electrolytes and Membrane for the All Vanadium Flow Battery

Batteries ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 49
Author(s):  
Wyndom S. Chace ◽  
Sophia M. Tiano ◽  
Thomas M. Arruda ◽  
Jamie S. Lawton
Keyword(s):  
Cyclic Voltammetry ◽  
Rotational Diffusion ◽  
Supporting Electrolyte ◽  
State Of Charge ◽  
Vanadium Redox Flow Battery ◽  
Bulk Solution ◽  
Flow Battery ◽  
Vanadium Concentration ◽  
H2so4 Concentration ◽  
Order Of Magnitude

The VO2+/VO2+ redox couple commonly employed on the positive terminal of the all-vanadium redox flow battery was investigated at various states of charge (SOC) and H2SO4 supporting electrolyte concentrations. Electron paramagnetic resonance was used to investigate the VO2+ concentration and translational and rotational diffusion coefficient (DT, DR) in both bulk solution and Nafion membranes. Values of DT and DR were relatively unaffected by SOC and on the order of 10−10 m2s−1. Cyclic voltammetry measurements revealed that no significant changes to the redox mechanism were observed as the state of charge increased; however, the mechanism does appear to be affected by H2SO4 concentration. Electron transfer rate (k0) increased by an order of magnitude (10−6 ms−1 to 10−8 ms−1) for each H2SO4 concentrations investigated (1, 3 and 5 M). Analysis of cyclic voltammetry switching currents suggests that the technique might be suitable for fast determination of state of charge if the system is well calibrated. Membrane uptake and permeability measurements show that vanadium absorption and crossover is more dependent on both acid and vanadium concentration than state of charge. Vanadium diffusion in the membrane is about an order of magnitude slower (~10−11 m2s−1) than in solution (~10−10 m2s−1).

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