Current efficiency of a disk-shaped ion-exchange membrane
Journal
Journal of the Chinese Institute of Chemical Engineers
Journal Volume
32
Journal Issue
5
Pages
437-444
Date Issued
2001
Author(s)
Jiang J.-M.
Abstract
The effect of the fixed charge distribution on the performance of a disk-shaped membrane is discussed theoretically. The present analysis generalizes the problem studied in the literature to a two-dimensional case. A parameter M characterizing the distribution of the fixed charge in the membrane is proposed to predict its current efficiency, £b. Four types of fixed charge distribution, including linear, exponential, trigonometric, and piecewise continuous distributions, are examined. If M < 0, the fixed charges are more concentrated on the left-hand side of the membrane, and the reverse is true if it is positive. If M = 0, the fixed charges are uniformly distributed. We find that £b increases monotonically with M regardless of the level of the electrical potential applied across the membrane. This is different from the result for a one-dimensional case, where £b has a local maximum as M varies. If M > 0, £b increases with the applied potential across the membrane, and the reverse is true if M < 0. If M¡÷0, £b is insensitive to the applied potential.
Subjects
Current efficiency
Electrodialysis
Fixed charge distribution
Ion exchange membrane
Nernst-Planck equation
Poisson equation
Type
journal article