Adsorption of Butyl Acetate on Mercury Electrode and Its Effect on Electroreduction of Zn Cations

2001 ◽  
Vol 66 (3) ◽  
pp. 411-422 ◽  
Author(s):  
Dorota Gugała ◽  
Dorota Sieńko ◽  
Jadwiga Saba
Keyword(s):  
Butyl Acetate ◽  
Mercury Electrode ◽  
Ester Group ◽  
Interaction Constant ◽  
Base Electrolyte ◽  
Capacity Curves ◽  
Charge Potential ◽  
Strong Adsorption ◽  
Kinetics Of ◽  
Zero Charge Potential

Adsorption of butyl acetate on the mercury electrode in 1 M, 0.5 M or 0.1 M NaClO4 is described. Differential capacity curves obtained in these solutions for various butyl acetate concentrations point to the strongest decrease in capacity in 0.1 M NaClO4 for the smallest concentration of the ester tested. At the same time the heights of desorption peaks in the solutions tested decrease in the following order: 1 M > 0.5 M > 0.1 M NaClO4. The obtained results show dynamic competitive adsorption in the ClO4--H2O-ester system. In all the systems studied the zero charge potential values determined with a streaming electrode are shifted towards positive potential with increasing ester concentration. These results suggest that the polar molecule of the ester adsorbs on the mercury electrode with its hydrophobic end while hydrophilic ester group is directed towards the solution. The values of the relative surface excess obtained in the range of potentials where the strong adsorption occurs, virtually do not depend on the base electrolyte concentration. The values of the Gibbs energy of adsorption ∆G0 determined from the Frumkin isotherm have also similar values at base concentrations of the electrolyte tested. The values of interaction constant A are radically different: the adsorbed molecules undergo repulsive force in 1 M NaClO4, whereas in 0.5 M and 0.1 M NaClO4 they are under weak attraction. In the range of more negative potentials, the adsorption layer was investigated following the kinetics of the reduction of Zn++ as a pilot ion. It was stated that the concentration of the base electrolyte fundamentally affects the process: the inhibition of butyl acetate decreases in the order 1 M > 0.5 M > 0.1 M NaClO4.

Adsorption of Iodide Ion from Aqueous NaI-NaClO4- Butan-1-ol at the Mercury-Electrolyte Interface

1999 ◽  
Vol 64 (12) ◽  
pp. 1925-1936 ◽  
Author(s):  
Jadwiga Saba ◽  
Kazimierz Sykut ◽  
Jolanta Nieszporek ◽  
Jan Szaran
Keyword(s):  
Surface Tension ◽  
Gibbs Energy ◽  
Adsorption Equilibrium ◽  
Standard Gibbs Energy ◽  
Mercury Electrode ◽  
Differential Capacity ◽  
Capacity Zero ◽  
Charge Potential ◽  
Adsorption Layers ◽  
Zero Charge Potential

Properties of the adsorption layers I--ClO4--H2O and I--ClO4--H2O-butan-1-ol on the mercury electrode were described using adsorption and kinetic parameters for the Zn(II) ion reduction. The systems were characterized by the measurements of differential capacity, zero charge potential and surface tension at this potential. The data were analysed to obtain the surface pressure and the charge due to specific adsorption of I- ions as a function of charge and concentration of I- ions. The standard Gibbs energy of adsorption ∆G0ad and parameter B obtained from the virial isotherm were compared. The rate constants of Zn(II) ion reduction as an ion affecting the adsorption equilibrium were determined.

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.

Measurements and Theoretical Interpretation of Points of Zero Charge/Potential of BSA Protein

Langmuir ◽  
2011 ◽  
Vol 27 (18) ◽  
pp. 11597-11604 ◽  
Author(s):  
Andrea Salis ◽  
Mathias Boström ◽  
Luca Medda ◽  
Francesca Cugia ◽  
Brajesh Barse ◽  
...  
Keyword(s):  
Theoretical Interpretation ◽  
Zero Charge ◽  
Charge Potential ◽  
Zero Charge Potential

scholarly journals Synthesis and degradation kinetics of TiO2/GO composites with highly efficient activity for adsorption and photocatalytic degradation of MB

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ruifen Wang ◽  
Kaixuan Shi ◽  
Dong Huang ◽  
Jing Zhang ◽  
Shengli An
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Adsorption Capacity ◽  
Degradation Kinetics ◽  
Removal Rate ◽  
Strong Adsorption ◽  
Degradation Activity ◽  
Kinetics Of ◽  
Stacking Structure ◽  
Synthesis And Degradation

AbstractPoriferous TiO2/GO (denoted as TGO-x%) photocatalysts with ultrathin grapheme oxide (GO) layer were prepared by a hydrothermal method, the adsorption and photocatalytic degradation and its kinetics about Methylene blue(MB) were studied systematically. All the TGO-x% showed improved adsorption and photodegradation performance. TGO-25% had excellent adsorptivity while TGO-20% exhibit the highest visible light photocatalytic degradation activity. The adsorption capacity for TGO-25% was 20.25 mg/gcatalyst along with the k1 was about 0.03393 min·gcatalyst/mg, this enhancement was mainly owing to the strong adsorption capacity of GO and the stacking structure of sheets and nanoparticles. GO sheets prevented the agglomeration of TiO2 particles and TiO2 nanoparticles also prevented the agglomeration of GO sheets, which could provides greater surface area. Besides, the remarkably superior photodegradation activity of TiO2/GO composites is mainly attribute to the strong absorption of visible light and the effective charge separation revealed by the photoluminescence, the total removal rate of MB is 97.5% after 35 min adsorption and 140 min degradation, which is 3.5 times higher than that of TiO2.

Analysis of the Electrode Kinetics of Ni(II) Reduction in Thiocyanate Media on the Dropping Mercury Electrode

2000 ◽  
Vol 65 (3) ◽  
pp. 326-342
Author(s):  
María S. Crespo-Pinilla ◽  
Fernando Mata-Pérez ◽  
Rosa M. Villamañán
Keyword(s):  
Ionic Strength ◽  
Compensation Effect ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Electrode Kinetics ◽  
Surface Process ◽  
Experimental Conditions ◽  
Dropping Mercury Electrode ◽  
Kinetics Of

A study of two prewaves of the Ni(II)-SCN- system was carried out under the experimental conditions when the influence of electroreduction of SCN- is negligible. Kinetics of Ni(II) reduction in thiocyanate media on the dropping mercury electrode was studied by DC Tast Polarography (DCTP) via determination of Koutecký's parameter χ; the influence of different variables was analyzed. The study of prewaves was performed using various polarographic techniques. Values of χ depend on the SCN- concentration, pH, ionic strength (Ψ-effect) and on the nature of the supporting electrolyte. The number of electrons n, the transfer coefficient α, the stoichiometric number ν, ∆H≠, and ∆S≠ were determined (compensation effect). The first prewave has character of a reaction in the solution, the second prewave is a surface process. Main features of both mechanisms are common: catalytic nature, one-electron step discharge and the rate-determining process between species of opposite charges.

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