Nanofiltration of 0.02 to 1.0 M sodium chloride solutions at 313 K with a dynamically formed Zr(IV) hydrous oxide-PAA membrane has been investigated. Linear and nonlinear relationships of the thermodynamics of irreversible processes have been used to obtain the practical transport coefficients, L p , σ and ω for this system. The results have been compared with other systems and the electrochemically active permselectivity demonstrated in terms of these coefficients for the charged membrane at low electrolyte concentrations.