Parameter	Description	Dimension
PEEK	polyester ether ketone
SPEEK	sulfonated polyester ether ketone
DMFA	dimethylformamide
$\delta$	diffusion boundary layer thickness	m
${\kappa }_s^{AC}$	electrical conductivity of membrane on alternating current	S/m
Θj	molar fraction of ion j
c0	electrolyte concentration in the bulk of the solution	mol/L
Tj	transport number of ion j
l	membrane thickness	m
P1.2	membrane selective permeability coefficient
F	Faraday’s constant	C/mol
h	solution compartment thickness	m
I	current	A/m2
R	resistance of the membrane	Ohm
S	membrane area	m2
V	volume of the solution	m3
zi	charge of ion i