$J_v$	volume flux (m s−1)
Jl, Jm, Jh	solute fluxes; (mol m−2s−1)
Il, Is, Im, Ih	ionic currents (A)
$L_p$	hydraulic conductivity coefficient (m−3N−1s−1)
$\sigma$	reflection coefficient
$P_E$	electroosmotic permeability coefficient (NA−1)
$\omega$	solute permeability coefficient (mol N−1s−1)
γ	van’t Hoff coefficient
R	gas constant (J mol−1K−1)
T	absolute temperature (K)
$\kappa$	electrical conductivity (Ω−1m−2)
${\tau }_j$	transfer number
$z_j$	valence
${\varkappa }_j$	ion number
$\overline{C}$	average concentration of the solution (mol m−3)
$\Delta {\psi }_m$	potential difference measured with two reversible electrodes (V)
${\tau }_a$, ${\tau }_c$	transfer number of anions (a) and cations (c) in the membrane
$t$	time (s)
$l_h$ and $l_l$	concentration boundary layers
δl, δh	thickness of the concentration boundary layers (m)
δm	membrane thickness (m)
$\Delta P$	mechanical pressure difference (Pa)
CBLs	concentration boundary layers
g	acceleration due to the fact of gravity (m s−2)
$D_l$, $D_h$	diffusion coefficients (m2s−1)
${\nu }_l$, ${\nu }_h$	the kinematic viscosity coefficients (m2s−1)
$C_e$, $C_i$	solution concentrations at the boundaries of M/$l_l$ and M/$l_h$ (mol m−3)
${\rho }_e$, ${\rho }_i$	solution densities at the boundaries of M/$l_l$ and M/$l_h$ (kg m−3)
$C_l$, $C_h$	solution concentrations beyond $l_l$ and $l_h$ (mol m−3)
${\rho }_l$, ${\rho }_h$	solution densities beyond $l_l$ and $l_h$ (kg m−3)