TRANSPORT OF IONS AND SOLVENT IN CONFINED MEDIA

A new theoretical approach is used to model the transport properties o f a cation-exchange membrane. By using the Navier-Stokes equation rela ted to the Poisson-Boltzmann relation, it is thus possible to determin e the solvent velocity in a membrane pore, and the influence of electr oosmosis on the transport properties of the polymer. The variation of the transport coefficients with salt concentration in the membrane por e was modeled as for simple electrolytes: taking electrophoretic inter actions and relaxation effect into account, we used MSA analytical exp ressions. We have investigated membrane conductivity and electrophoret ic sodium mobility measurements when the membrane was equilibrated wit h NaCl solution. Good agreement was found between the experimental res ults and our theoretical model.