SITE CONCENTRATION DETERMINATION IN LIQUID ION-EXCHANGE MEMBRANES .3. EXPERIMENTAL

Potentiometric responses of Aliquat-nitrate liquid ion exchanger membranes in nitrobenzene, at various loadings, have been measured for bathing solutions of tetraethyl through tetrapentyl ammonium nitrates. Deviations from Nernstian nitrate responses, at high activities have been used to compute average site concentrations assuming onset of Donnan Exclusion Breakdown by cation penetration. Confirmation of theory includes agreement of observed with known site concentrations, and agreement of observed with calculated response slopes after Donnan Breakdown. The essential dependence of failure on salt extraction coefficients, ignored in classical theory, is clear from systematic dependence of results on extraction coefficient data. © 1979 Elsevier Sequoia S.A.