0000000000186060

AUTHOR

H. Holdik

showing 3 related works from this author

Electric field enhanced water dissociation at the bipolar membrane junction from ac impedance spectra measurements

1998

Abstract Preliminary experimental results of the ac impedance spectra of a bipolar ion-exchange membrane are reported and interpreted on the basis of a previous theoretical model based on the Nernst–Planck/Poisson equations. It is shown that the experiments can provide valuable electrochemical information about the bipolar junction structure and the electric-field enhanced water dissociation phenomenon that occurs at this junction, although the high number of unknown parameters involved makes it difficult to obtain accurate values for the parameters characteristic of this phenomenon.

Chemical dissociationChemistryGeneral Chemical EngineeringAnalytical chemistryElectrochemistryMolecular physicsDissociation (chemistry)Analytical Chemistrysymbols.namesakeMembraneElectric fieldAc impedance spectraElectrochemistrysymbolsNernst equationElectrical impedanceJournal of Electroanalytical Chemistry
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A Simple Model for Ac Impedance Spectra in Bipolar Membranes

1996

A new model accounting for the ac impedance spectra of synthetic ion-exchange bipolar membranes is presented. The theoretical approach is based on the Nernst−Planck and Poisson equations and applies some of the concepts used in the semiconductor pn junctions to the case of a bipolar membrane. The results presented are the current−voltage curves and the impedance spectra at electric currents above the limiting current. It is shown that the model is able to identify the main contributions to the bipolar membrane impedance and gives valuable information about the bipolar junction structure and its influence on the characteristic parameters involved in the field-enhanced water dissociation phen…

Mathematical modelChemistrybusiness.industryGeneral EngineeringLimiting currentAnalytical chemistryMolecular physicsDissociation (chemistry)MembraneSemiconductorMembrane impedanceAc impedance spectraPhysical and Theoretical ChemistryElectric currentbusinessAstrophysics::Galaxy AstrophysicsThe Journal of Physical Chemistry
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Ion selectivity and water dissociation in polymer bipolar membranes studied by membrane potential and current–voltage measurements

2000

Abstract A polymer bipolar ion-exchange membrane consists of a layered structure involving one cation and one anion ion-exchange layer joined together in series. In this study, the ionic selectivity and water dissociation rate of six commercial bipolar membranes was evaluated from the measurements of the membrane potential in a concentration cell and the current–voltage curve in a four-point measuring cell. Bipolar membrane technology requires polymer membranes presenting high ion selectivities and water dissociation rates, and in this paper we have addressed the basic physico-chemical phenomena involved, both theoretically and experimentally. We have shown that the effects of the bipolar j…

Membrane potentialPolymers and PlasticsChemistryOrganic ChemistrySynthetic membraneAnalytical chemistryDissociation (chemistry)Concentration cellIonMembraneChemical engineeringMaterials ChemistrySemipermeable membraneIon transporterPolymer
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