STUDIES OF INORGANIC PRECIPITATE MEMBRANE - EVALUATION OF MEMBRANE SELECTIVITY FROM BI-IONIC POTENTIAL AND CONDUCTIVITY MEASUREMENTS

Bi-ionic and multi-ionic potential across parchment supported mercuric sulphide membrane with various combinations of 1 : 1 electrolytes at different concentrations have been measured. Membrane conductivity in contact with a single electrolyte has been experimentally determined to evaluate the selectivity of the membrane with the predetermined values of the intra-membrane mobility ratio. The selectivity sequence of the membrane has been found as K+ > Na+ > Li+ which on the basis of the Eisenman-Sherry model of membrane selectivity, points towards the weak field strength of the charge groups attached to the membrane matrix.