Electrosorption of vinyltriphenyl and propargyltriphenylphosphonium cations from methanolic solutions at the dropping and hanging mercury drop electrodes

1986 ◽  
Vol 64 (12) ◽  
pp. 2279-2283
Author(s):  
Anastasia Christodoulou ◽  
Anastos Anastopoulos ◽  
Demetrios Jannakoudakis
Keyword(s):  
Adsorption Isotherms ◽  
Mercury Electrode ◽  
Adsorption Parameters ◽  
Methanolic Solution ◽  
Solution Interface ◽  
Ionic Adsorption ◽  
Interfacial Behaviour

The interfacial behaviour of vinyltriphenyl and propargyltriphenylphosphonium cations at the mercury electrode – methanolic solution interface is studied by phase selective ac polarography using dropping Hg electrodes of short (≤5 s) and long [Formula: see text] drop times and the hanging Hg drop electrode.The various adsorption parameters are determined on the basis of non-ionic adsorption isotherms involving capacitance data independent as well dependent on time.

Surface behaviour of tetrapropylammonium cation at the mercury/solution interface measured by use of controlled convective adsorptive accumulation

1985 ◽  
Vol 50 (11) ◽  
pp. 2525-2534 ◽  
Author(s):  
Ladislav Novotný ◽  
Ivan Smoler
Keyword(s):  
Surface Tension ◽  
Adsorption Isotherms ◽  
Adsorption Energy ◽  
Surface Coverage ◽  
Adsorption Parameters ◽  
Surface Tension Data ◽  
Solution Interface ◽  
Constant Potential ◽  
Drop Time ◽  
Constant Charge

Using drop time technique with long drop times and a controlled convection of the solution the surface tension data of Hg with tetrapropylammonium perchlorate in 0.1 mol l-1 NaClO4 in the concentration range 4 . 10-6 - 3 . 10-3 mol l-1 have been obtained. The corresponding adsorption parameters have been evaluated from the Frumkin isotherm both at constant potential E and at constant charge q. Both E and q could be chosen as an independent electrical variable. The maximum free adsorption energy amounts to approx. -36.5 kJ mol-1. The congruence of adsorption isotherms with respect to E and with respect to q was very well fulfilled for the surface coverage Θ ⪬ 0.6-0.7.

Time dependent interfacial behaviour of tributylphosphine oxide at the mercury-solution interface

1985 ◽  
Vol 50 (12) ◽  
pp. 2804-2813 ◽  
Author(s):  
Anastos Anastopoulos ◽  
Panaghiotis Nikitas ◽  
Demetrios Jannakoudakis
Keyword(s):  
Mercury Electrode ◽  
Quantitative Description ◽  
Differential Capacitance ◽  
Time Dependent ◽  
Large Drop ◽  
Adsorption Parameters ◽  
Capacitance Measurements ◽  
Dropping Mercury Electrode ◽  
Interfacial Behaviour ◽  
Drop Time

A series of methods are used for the quantitative description of the time dependent interfacial behaviour of tributylphosphine oxide (TBPO). These methods include measurements of the interfacial tension by a capillary electrometer as well as differential capacitance measurements with a dropping mercury electrode (D.M.E.) of short drop times (⪬5 s), a D.M.E. of large drop times (~20 s) and a hanging mercury drop electrode (H.M.D.E.). The capacitance measurements with large drop times reveal the existence of peculiarities during the development of the adsorption film. The adsorption equilibrium of TBPO, at the vicinity of the adsorption maximum, is generally established within times shorter than 10 s. At the region of the adsorption pseudocapacity, time intervals ranging from 200 to 400 seconds are required for the equilibrium. The adsorption parameters derived with the large drop time D.M.E., are in reasonable agreement with those obtained by electrocapillary measurements.

The Interfacial Behaviour of Mono-, Di-, and Triphosphate of Inosine at the Charged Interface

1996 ◽  
Vol 61 (11) ◽  
pp. 1600-1608
Author(s):  
Mohamed E. Ahmed
Keyword(s):  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Adsorption Parameters ◽  
Buffer Solutions ◽  
Ph Values ◽  
Adsorption Equilibria ◽  
Charged Interface ◽  
Interfacial Behaviour ◽  
Phase Sensitive ◽  
Adsorption Stage

The interfacial behaviour and adsorption equilibria of mono-, di-, and triphosphate of inosine (IMP, IDP, and ITP) were carried out in different buffer solutions by phase-sensitive ac voltammetry at HMDE. The characteristic properties and adsorption parameters of dilute and compact layers were evaluated from the obtained Frumkin isotherm at different pH values. The effect of some divalent metal ions on the adsorption stage and association of the investigated compounds has been studied.

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.

Hydroxyproline adsorption on a mercury electrode in neutral solution

1991 ◽  
Vol 69 (10) ◽  
pp. 1528-1534 ◽  
Author(s):  
M. M. Gómez
Keyword(s):  
Dipole Moment ◽  
Adsorption Process ◽  
Normal Component ◽  
Mercury Electrode ◽  
Hydroxyl Group ◽  
Neutral Solution ◽  
Pyrrolidine Ring ◽  
Adsorption Parameters ◽  
Gibbs Energies ◽  
Comparison Of The Results

The adsorption of hydroxyproline (HPRO) on mercury in aqueous solutions of 10−2 M KClO4 has been determined from electrocapillary and capacity measurements. Comparison of the results obtained for HPRO with those reported for proline (PRO) shows that the presence of a hydroxyl group in the molecule has a small effect on the adsorption process. The respective values for adsorption parameters are −7 and −5 μC cm−2 for the charges of maximum adsorption, −13.0 and −10.4 kj mol−1 for the standard Gibbs energies of adsorption at zero charge, and −1.28 and +0.6 for the α parameter in the Frumkin isotherms. According to the analysis carried out for the normal component of the dipole moment of HPRO, −0.8 D, the more probable orientation of this aminoacid adsorbed on mercury is with the pyrrolidine ring parallel to the electrode surface resting the OH group away from the surface. Key words: adsorption, double layer, aminoacids, hydroxyproline.

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