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1

Study of Permanganate Ion Transfer Across an Electrified Water/Nitrobenzene Interface

Heli H., Shamsipur M., Mousavi M.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 2

313-323

EN

The transfer of permanganate anion across a water/nitrobenzene interface has been studied by cyclic voltammetry and chronopotentiometry techniques. The diffusion coefficient of the species in aqueous phase was obtained by means of both cyclic voltammetry (DW = 2.75x10-5cm2 s-1) and chronopotentiometry (DW = 2.79x10-5cm2 s-1). The standard potential of transfer was obtained as deltaE0' = -198 mVand the transfer coefficient has also been calculated from the Tafel slope as alfa = 0.4. The effect of temperature on the ion transfer process was studied over a wide range (10-70 graduate C). The Gibbs activation energy of the ion transfer across the interface (deltaG = 12.09 kJ mol-1) and the Gibbs activation energy of ion transport in the bulk of aqueous solution (deltaG = 12.58 kJ mol-1) have been obtained from the temperature dependence of transfer rate data.

2

AC-impedance studies on ion transfer across ionophore-based ion-selective membranes

Mikhelson K. N.

Chemia Analityczna

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2006

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Vol. 51, No. 6

853-867

EN

Fundamental complexities related to the studies on inter facial charge transfer at ionophore--based ion-selective electrode (ISE) membranes have been briefly discussed. The presented data obtained from ac-impedance studies on ISEs selective to K+, Na\ Li+, and Ca2+ ions have shown fast interfacial transfer of primary ions, and also of interfering ions, supporting the concept of fast establishment of interfacial electrochemical equilibrium towards all competing ions in the solution.

PL

Pokrótce omówiono podstawową trudność /wiązaną z badaniami nad między fazowy m przeniesieniem ładunku w zawierających jonofor membranach elektrod jonoselektywnych. Przedstawione dane uzyskane w badaniach ac-impedancyjnych ISE selektywnych najony K+. Na+, Li+, i Ca2+ sugerują szybkie między fazowe przeniesienie jonów głównych, jak również jonów przeszkadzających. potwierdzając koncepcje szybkiego ustalenia międzyfa-zowej równowagi elektrochemicznej wobec wszystkich konkurencyjnych jonów w roztworze.

3

Ceramic Carbon Electrode Modified with Redox Probe and Salt Solution in Hydrophobic Polar Solvent

Shul G., Opallo M.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 9

1449-1456

EN

Ceramic carbon electrode modified with redox probe and salt solution in hydrophobic polar solvent was prepared and studied. The electrode consisting of graphite powder, homogeneously dispersed in hydrophobic silicate matrix, was prepared from the mixture of methyltrimethoxysilane based sol and graphite powder by sol-gel method. Then it was immersed in t-butylferrocene and tetrabutylammonium perchlorate solution in nitrobenzene. The electrode properties were investigated by cyclic voltammetry and chronoamperometry in KNO3 solutions of different concentration. Linear polarization of the electrode towards positive potentials results in peak shaped symmetric voltammogram originating from electrooxidation of t-butylferrocene. The peak current is few times larger than that obtained when organic phase does not contain salt. It is also proportional to the concentration of the redox probe in organic phase and salt in aqueous phase, whereas the midpeak potential is almost not affected by these factors. The reasons of these effects are discussed.

4

Silicate solvated by an organic solvent as electrolyte or electrode material

Opallo M.

Materials Science

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2003

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Vol. 21, No. 4

453-460

EN

Preparation and properties of silicate gels solvated by organic solvents as electrolytes or electrode materials were summarised. A silicate matrix based on tetraalkoxysilane, trialkoxysilane modified with organic groups or a mixture of these two, modified by organic solvents or solutions is the principal komponent of all the systems studied. The material used as the electrolyte is filled with a salt solution in an organic polar solvent or in the case of hybrid organic-inorganic silicate matrix it is functionalised with tetraalkylammonium groups with a pure solvent. The electrodes are made of a composite material consisting of graphite particles, silicate matrix functionalised with methyl groups and filled with a pure or diluted redox liquid.