ELECTROCHEMICAL CHARACTERIZATION OF POROUS MEMBRANES WITH ADSORBED CHARGES FROM CONVECTIVE DIFFUSION AND COUNTERCURRENT ELECTROLYSIS EXPERIMENTS

Experimental methods for the electrochemical characterization of porou s membranes with adsorbed charges are described. Convective diffusion and counter-current electrolysis experiments permit the determination of the membrane constant (effective membrane area/membrane thickness) and the ion transport numbers, respectively. The first one is a key pa rameter in electrokinetic experiments, while the latter provides infor mation on the membrane selectivity. A simple, theoretical model based on the Nernst-Planck equation and the Langmuir isotherm can be used to describe the coupling between ion adsorption and transport.