$J$	Ions molar flux
$D$	Apparent diffusion coefficiente
$C$	Mole concentration per unit volumen
$\Delta x$	Cation exchange membrane thickness
$z$	Number of electrons per ion
$\phi$	Electric potential
$R$	Ideal gas constant
$T$	Temperature
$i$	Electric current density
$F$	Faraday Constant
$N$	Number of compartments
$t$	time
$A$	Effective membrane area
$\lambda$	Molar conductivity
$K$	Kohlraush constant
$k$	Specific conductivity
$R^s$	Electric resistance of solution
$d$	Distance between membranes
$de$	Electrode compartment thickness
$E$	Cell potential
$\eta$	overpotential
$U$	Voltage
$mp$	mass produced
$SEC$	Specific electrical energy consumption
$\varphi$	Current efficiency
$m$	molality
$M$	Molar mass
$V$	Solution volume
$\rho$	density
Subscripts and Superscripts
$cm$	Cation membrane
$cms$	Cation membrane surface
$fix$	Fixed, associated with fixed charges of the cation exchange membrane or bipolar membrane
$i$	Ionic or molecular species
$s$	solution
$0$	Initial time zero
$cou$	counterion
$co$	Co-ion
$prod$	Production
$lim$	Related to limiting current density
$bpl$	Bipolar membrane layer
$a$	Anionic
$c$	Cationic
$m$	molar
°	standar
$mem$	Membrane
$bpm$	Bipolar membrane
$e$	equilibrum
$cell$	cell
$elec sol$	Electrolyte solution