Adsorption of tetramethylthiourea in concentrated NaClO4 solutions

2009 ◽  
Vol 74 (9) ◽  
pp. 1309-1321 ◽  
Author(s):  
Dorota Sieńko ◽  
Dorota Gugała-Fekner ◽  
Jolanta Nieszporek ◽  
Zygmunt Fekner ◽  
Jadwiga Saba
Keyword(s):  
Double Layer ◽  
Interaction Parameter ◽  
Mercury Electrode ◽  
Differential Capacity ◽  
Surface Excess

Tetramethylthiourea electrosorption behaviour on the mercury electrode in 2, 3 and 4 mol l–1 NaClO4 was determined by means of double-layer differential capacity measurements. The relative surface excess Γ′ of the adsorbate calculated from the surface pressures depended on the NaClO4 concentration. A clear influence of NaClO4 concentration appeared in the changes of interaction parameter A obtained from the Flory–Huggins isotherm and in the permittivity parameter of the inner layer.

Differential capacity of the mercury electrode in dilute 1,1-valent electrolytes

1982 ◽  
Vol 47 (1) ◽  
pp. 190-195
Author(s):  
Valerii Kozlov ◽  
Valentina Vilinskaya ◽  
Gurami Tedoradze
Keyword(s):  
Double Layer ◽  
Mercury Electrode ◽  
Electrolyte Solutions ◽  
Differential Capacity ◽  
Double Layer Capacity

The double layer capacity has been measured in dilute 1,1-valent electrolyte solutions (HCl, KCl, NaF) at infrasonic frequencies. The results obtained confirm the validity of the Gouy-Chapman theory for electrolyte solutions in the concentration range 10-3 - 10-5 mol/dm3.

Adsorption of tert-butyl alcohol at the Hg|aqueous perchlorate interface in the presence of tetramethylthiourea

2009 ◽  
Vol 74 (10) ◽  
pp. 1517-1530
Author(s):  
Dorota Gugała-Fekner ◽  
Zygmunt Fekner ◽  
Jolanta Nieszporek ◽  
Dorota Sieńko ◽  
Jadwiga Saba
Keyword(s):  
Double Layer ◽  
Butyl Alcohol ◽  
Repulsive Interaction ◽  
Differential Capacity ◽  
Surface Excess ◽  
Capacity Measurement ◽  
Tert Butyl ◽  
Tert Butyl Alcohol

The electrosorption behavior of tert-butyl alcohol at the mercury|aqueous NaClO4– tetramethylthiourea was determined by a double layer differential capacity measurement. Adsorption of tert-butyl alcohol was analyzed using the constants obtained from the modified Flory–Huggins and virial isotherm. An increase in the relative surface excess for tert- butyl alcohol with increasing NaClO4 concentration in the range from 0.1 to 1.0 M was confirmed. The observed effect may be the result of the weakest repulsive interaction between adsorbed tert-butyl alcohol molecules in 1.0 M NaClO4 with 0.05 M tetramethylthiourea.

scholarly journals Adsorption of tert-butanol at the electrode from concentrated NaClO4 solutions

2013 ◽  
Vol 11 (1) ◽  
pp. 86-93 ◽  
Author(s):  
Jolanta Nieszporek
Keyword(s):  
Double Layer ◽  
Physical Process ◽  
Organic Substance ◽  
Electrode Surface ◽  
Mercury Electrode ◽  
Surface Excess ◽  
Major Drawback ◽  
Tert Butanol ◽  
Zero Charge

AbstractThe parameters of the double layer for tert-butanol adsorption determined in the supporting electrolytes: 2 mol dm−3, 3 mol dm−3 and 4 mol dm−3 NaClO4, show an increase of tert-butanol adsorption on the mercury electrode together with the increase of NaClO4 concentration. The adsorption of tert-butanol on the electrode takes place via the −CH3 group which is shown by the changes in the values of zero charge potentials, E z. On the basis of the analysis of the changes of relative surface excess values, Γ′, and the parameters determining the maximum adsorption, the process of adsorption in the discussed systems can be recognized as a physical process. Besides, it can be said that a major drawback in the process of adsorption of the organic substance on the electrode is to remove water from the electrode surface.

Studies of a Mixed Adsorption Layer of Butan-1-ol and o-Toluidine on Mercury Electrode

2002 ◽  
Vol 67 (11) ◽  
pp. 1579-1588 ◽  
Author(s):  
Dorota Sieńko ◽  
Dorota Gugała ◽  
Jolanta Nieszporek ◽  
Joanna Jankowska ◽  
Jadwiga Saba
Keyword(s):  
Thermodynamic Analysis ◽  
Adsorption Layer ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Interaction Constant ◽  
Repulsive Interaction ◽  
Surface Excess ◽  
Adsorption Parameters ◽  
Frumkin Isotherm ◽  
Adsorption Layers

The results of thermodynamic analysis of o-toluidine adsorption on a mercury electrode in the presence of various butan-1-ol amounts complete our previous studies on properties of mixed adsorption layers of toluidine isomers-butan-1-ol. The values of the relative surface excess Γ'°T obtained for o-toluidine show that adsorption of this compound decreases with increasing of butan-1-ol concentration. Analysis of adsorption parameters derived from the Frumkin isotherm indicates that in the presence of 0.33 M BuOH in 1 M NaClO4 with adjusted pH 3 as supporting electrolyte, ∆G0 values for o-toluidine are the highest and, at the same time, the strongest repulsive interaction occurs. In the presence of 0.11 M butan-1-ol, smaller values of ∆G0 for o-toluidine correspond to weaker repulsive interaction. Therefore the change of the Γ'°T value for o-toluidine as a function of butan-1-ol concentration is the result of mutual changes of ∆G0 and interaction constant A between adsorbate molecules.

The diffuse double layer in ionic liquids

2009 ◽  
Vol 74 (11-12) ◽  
pp. 1665-1674 ◽  
Author(s):  
W. Ronald Fawcett ◽  
Peter J. Ryan
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Double Layer ◽  
Room Temperature ◽  
Potential Drop ◽  
Diffuse Double Layer ◽  
Differential Capacity ◽  
Monte Carlo Data ◽  
Monovalent Ions ◽  
Salt Systems

The equations used to describe the diffuse double layer in the Eigen–Wicke model of ionic liquids are presented. They are then used to estimate the potential drop across the diffuse layer and its differential capacity for two representative systems which contain monovalent ions of equal diameter. The first one is molten RbCl at 750 °C. The second system is a room temperature ionic liquid with typical parameters to describe its properties. The results of the calculations are compared with the available experimental data. It is concluded that the Eigen–Wicke model does not consider the change in local potential experienced by a given ion in the ionic liquid. The need for Monte Carlo data for the diffuse double layer in molten salt systems is emphasized.

Differential Capacity of the Double-Layer Formed at a Solid Electrode (Pt, Au)/Ionic Liquid Interface

2007 ◽  
Vol 62 (3-4) ◽  
pp. 187-190 ◽  
Author(s):  
Andrzej Lewandowski ◽  
Maciej Galiński ◽  
Sebastian R. Krajewski
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Double Layer ◽  
Electrode System ◽  
Liquid Interface ◽  
Potential Range ◽  
Differential Capacity ◽  
Impedance Measurements ◽  
Solid Electrode ◽  
Double Layer Capacity

The differential capacity at the electrode (Pt, Au)/ionic liquid interface of 18 ionic liquids (ILs), was measured applying chronoamperometry. The measurements were done by a two electrode system. The double layer capacity at the Pt/IL and Au/IL interface was 1 - 8 μF/cm2. The capacity, estimated from the impedance measurements, was approximately constant within a potential range of ca. 3 V.

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