scholarly journals INDIRECT METHOD OF MATHEMATICAL MODELING OF MASS TRANSFER IN THE DIFFUSION LAYER AT ION-EXCHANGE MEMBRANE FOR THE GALVANODYNAMIC MODE

2017 ◽  
Vol 1 (№9 2017) ◽  
pp. 105-111
Author(s):  
A.M. Uzdenova ◽  
M.Kh. Urtenov
Keyword(s):  
Mathematical Modeling ◽  
Mass Transfer ◽  
Ion Exchange ◽  
Diffusion Layer ◽  
Indirect Method ◽  
Ion Exchange Membrane ◽  
Exchange Membrane

Mass transfer analysis of pervaporation through an ion exchange membrane

Desalination ◽  
1993 ◽  
Vol 90 (1-3) ◽  
pp. 259-276 ◽  
Author(s):  
P. Schaetzel ◽  
E. Favre ◽  
Q.T. Nguyen ◽  
J. Neel
Keyword(s):  
Mass Transfer ◽  
Ion Exchange ◽  
Ion Exchange Membrane ◽  
Exchange Membrane

Mass transfer through a weak acid ion-exchange membrane

1993 ◽  
Vol 38 (2-3) ◽  
pp. 329-340 ◽  
Author(s):  
P. Schaetzel ◽  
B. Auclair
Keyword(s):  
Mass Transfer ◽  
Ion Exchange ◽  
Weak Acid ◽  
Ion Exchange Membrane ◽  
Exchange Membrane

scholarly journals 1D Mathematical Modelling of Non-Stationary Ion Transfer in the Diffusion Layer Adjacent to an Ion-Exchange Membrane in Galvanostatic Mode

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 84 ◽  
Author(s):  
Aminat Uzdenova ◽  
Anna Kovalenko ◽  
Makhamet Urtenov ◽  
Victor Nikonenko
Keyword(s):  
Ion Exchange ◽  
Charge Density ◽  
Space Charge ◽  
Diffusion Layer ◽  
Current Density ◽  
Space Charge Density ◽  
Ion Exchange Membrane ◽  
Quasi Equilibrium ◽  
Ion Transfer ◽  
Exchange Membrane

The use of the Nernst–Planck and Poisson (NPP) equations allows computation of the space charge density near solution/electrode or solution/ion-exchange membrane interface. This is important in modelling ion transfer, especially when taking into account electroconvective transport. The most solutions in literature use the condition setting a potential difference in the system (potentiostatic or potentiodynamic mode). However, very often in practice and experiment (such as chronopotentiometry and voltammetry), the galvanostatic/galvanodynamic mode is applied. In this study, a depleted stagnant diffusion layer adjacent to an ion-exchange membrane is considered. In this article, a new boundary condition is proposed, which sets a total current density, i, via an equation expressing the potential gradient as an explicit function of i. The numerical solution of the problem is compared with an approximate solution, which is obtained by a combination of numerical solution in one part of the diffusion layer (including the electroneutral region and the extended space charge region, zone (I) with an analytical solution in the other part (the quasi-equilibrium electric double layer (EDL), zone (II). It is shown that this approach (called the “zonal” model) allows reducing the computational complexity of the problem tens of times without significant loss of accuracy. An additional simplification is introduced by neglecting the thickness of the quasi-equilibrium EDL in comparison to the diffusion layer thickness (the “simplified” model). For the first time, the distributions of concentrations, space charge density and current density along the distance to an ion-exchange membrane surface are computed as functions of time in galvanostatic mode. The calculation of the transition time, τ, for an ion-exchange membrane agree with an experiment from literature. It is suggested that rapid changes of space charge density, and current density with time and distance, could lead to lateral electroosmotic flows delaying depletion of near-surface solution and increasing τ.

Effect of the ion-exchange-membrane/solution interfacial characteristics on the mass transfer at severe current regimes

2012 ◽  
Vol 48 (6) ◽  
pp. 610-628 ◽  
Author(s):  
N. D. Pis’menskaya ◽  
V. V. Nikonenko ◽  
N. A. Mel’nik ◽  
G. Pourcelli ◽  
G. Larchet
Keyword(s):  
Mass Transfer ◽  
Ion Exchange ◽  
Ion Exchange Membrane ◽  
Exchange Membrane ◽  
Interfacial Characteristics
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