EFFECT OF UNSTIRRED SOLUTION LAYERS ON THE THERMAL MEMBRANE-POTENTIALTHROUGH CATION-EXCHANGE MEMBRANES

The thermal membrane potential through a cation-exchange membrane has been determined under different experimental situations. In all cases, a good linear dependence between the thermal membrane potential, Delt a psi, and the temperature difference, Delta T, established between bo th external electrolyte solutions has been observed. The value of Delt a psi decreases notably when the concentration of the electrolyte solu tion used is increased and it also depends on the type of the cation i nvolved, so that Delta psi decreases when the corresponding atomic num ber increases. The value of the temperature coefficient, Delta psi/Del ta T, is notably affected by the unstirred solution layers adjoining t he membrane surfaces. A theoretical model is presented to determine th e influence of the temperature polarization effect on the thermal memb rane potential value.