Nonequilibrium hysteresis and Wien effect water dissociation at a bipolar membrane.
Phys Rev E Stat Nonlin Soft Matter Phys
; 86(5 Pt 2): 056104, 2012 Nov.
Article
in En
| MEDLINE
| ID: mdl-23214840
ABSTRACT
As in electrochemical cyclic voltammetry, time-periodic reverse voltage bias across a bipolar membrane is shown to exhibit hysteresis due to transient effects. This is due to the incomplete depletion of mobile ions, at the junction between the membranes, within two adjoining polarized layers; the layer thickness depends on the applied voltage and the surface charge densities. Experiments show that the hysteresis consists of an Ohmic linear rise in the total current with respect to the voltage, followed by a decay of the current. A limiting current is established for a long period when all the mobile ions are depleted from the polarized layer. If the resulting high field within the two polarized layers is sufficiently large, water dissociation occurs to produce proton and hydroxyl traveling wave fronts which contribute to another large jump in the current. We use numerical simulation and asymptotic analysis to interpret the experimental results and to estimate the amplitude of the transient hysteresis and the water-dissociation current.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Water
/
Membranes, Artificial
/
Models, Chemical
Language:
En
Journal:
Phys Rev E Stat Nonlin Soft Matter Phys
Journal subject:
BIOFISICA
/
FISIOLOGIA
Year:
2012
Document type:
Article
Affiliation country:
United kingdom