Chronopotentiometry of pure electrolytes with anion-exchange donnan exclusion membranes

Crespo Paravano, Gaston Adrian; Ghahraman Afshar, Majid; Bakker, Eric

doi:10.1016/j.jelechem.2014.08.007

Scientific article

English

Chronopotentiometry of pure electrolytes with anion-exchange donnan exclusion membranes

Contributors

Crespo Paravano, Gaston Adrian; Ghahraman Afshar, Majid; Bakker, Eric

Published in

Journal of Electroanalytical Chemistry, vol. 731, p. 100-106

Publication date

2014

Abstract

We explore here the chronopotentiometric responses of pure electrolytes with anion-exchange Donnan exclusion membranes (IEDEM). As these electrolytes are locally depleted at the membrane surface in the absence of background electrolyte, electrical migration cannot be neglected. Yet, a linear relationship between the signal readout (square root of the transition time, τ0.5) and the electrolyte concentration is observed, albeit with much larger apparent diffusion coefficients than expected. We develop here a simplified migration–diffusion model based on the Nernst–Planck equation to explain the experimental data. As the flux of the counterion at the membrane surface must be zero for a permselective membrane, electrical migration is understood to precisely counteract the contribution of diffusional mass transport. This results in a simplified understanding of the mass transport processes at such membranes. Numerical simulations are performed to compare the predicted and experimental data. Based on these mechanistic and practical insights, permselective anion-exchange membranes are shown to respond to a range of ions in a similar fashion in the concentration range of 0.1–10 mM. The membranes are able to sustain significantly high current densities of 0.4 mA mm−2 and may become useful as ion detectors or counter electrode separation materials.

Keywords

Chronopotentiometry
Perm-selective membranes
Ion-selective membranes
Electrical migration

UNIGE affiliation entities

Faculté des sciences / Section de chimie et biochimie / Département de chimie minérale, analytique et appliquée

Citation (ISO format)

CRESPO PARAVANO, Gaston Adrian, GHAHRAMAN AFSHAR, Majid, BAKKER, Eric. Chronopotentiometry of pure electrolytes with anion-exchange donnan exclusion membranes. In: Journal of Electroanalytical Chemistry, 2014, vol. 731, p. 100–106. doi: 10.1016/j.jelechem.2014.08.007

Article (Published version)

Identifiers

PID : unige:144149
DOI : 10.1016/j.jelechem.2014.08.007

Additional URL for this publication

https://linkinghub.elsevier.com/retrieve/pii/S1572665714003397

Journal ISSN

0022-0728

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Chronopotentiometry of pure electrolytes with anion-exchange donnan exclusion membranes

Contributors

Published in

Publication date

Abstract

Keywords

UNIGE affiliation entities

Citation (ISO format)

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Additional URL for this publication

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Technical informations

Creation

First validation

Update

Status update

Last indexation