Bi-ionic potentials across liquid anion exchanger membranes

The bi-ionic potentials, B. I. P.'s, arising in cells of the type: A⁺L⁻c₁| liquid anion exchanger membrane of extreme anionic selectivity| A⁺M⁻c₁, are surveyed briefly but systematically. The membranes consisted of trioctyl-propyl ammonium salts dissolved ino-dichlorobenzene. As anticipated on the basis of previous theoretical and experimental work on porous membranes, the following regularities were observed. The B.I.P. arising with any pair of critical ions is essentially independent of the activity of the aqueous electrolytic solutions used, and is essentially independent of the degree of loading of the membrane with ion-exchanger compound. The B.I.P.'s are higher the farther apart the two critical anions under consideration, L⁻ and M⁻, are in the Hofmeister The B.I.P.'s, as shown in a series of 21 cells with seven different univalent critical ions are algebraically additive, in the sense that within the limits of the experimental error $$B.I.P._{L^ - /M^ - } + B.I.P._{M^ - /N^ - } = B.I.P._{L^ - /N^ - } ,$$ where L⁻, M⁻, and N⁻ represent any arbitrary combination of the anions used.