DEMINERALIZATION OF AQUEOUS-SOLUTIONS ON CHARGED NANOFILTRATION AND ULTRAFILTRATION MEMBRANES

The selectivity of synthesized, charged membranes is experimentally st udied within a wide range of concentrations of a model NaCl solution. Theoretical analysis of the selectivity as a function of the concentra tion of the model solution is performed using the model of a homogeneo us charged membrane, with the assumption that the state of water insid e the membrane differs from the bulk state. The adopted model of ion t ransport offers a satisfactory qualitative description but fails to al ways provide an adequate interpretation of experimental data. By using a special mathematical treatment of the experimental data, each membr ane is characterized by the density of fixed charge and the total chan ge of the Gibbs energy of sodium and chlorine ions transferred from so lution to membrane.