1. The equation for ion flux through liquid membrane interposed between two aqueous electrolyte solutions was derived on the basis of nonequilibrium thermodynamics. The flux equation was the same in form as that previously derived for the solid membrane. This indicates that the theoretical expressions for the electrical properties of membrane are identical with those for the solid membrane.
2. It was shown that the liquid membranes prepared by cetylpyridinium chloride CPC and di-n-dodecyl phosphate DDP behaved as an ideal membrane electrode for anion and cation, respectively.
3. The membrane potentials were measured with the systems, NaClCPCNaClO
4, NaClCPCNa
2SO
4 and CaCl
2|DDPMgCl
2. The results were treated by the theoretical equation
VO X, Y =2
RT/
ZX+
ZY F ln
ZYPYaY/
ZXPXaXwhere X and Y refer to counter ions, X and Y, respectively and
Z,
a and
P, valency, activity and permeability coefficient, respectively. The bi-ionic potential B. I. P.
VO X, Y, was found to be linear against the logarithm of
aY/
aX with a constant slope of 4.6
RT/
ZX+
ZY F. This implies that
ZYPY/
ZXPX=
Kpot.X, Y is constant.
4. The orders of
KpotX, Y in various bi-ionic systems were ClO
4SCN NO
3Cl-, Mg
2+Ca
2+Sr
2+Ba
2+, Ca
2Cs
+Na
+K
+. These orders were consistent with lyotropic series except for that of alkali metal ions.
5. The additivity rule
Vo (X, Y)=
Vo (X, Z) +
Vo Z, Y, was confirmed with any set of the hi-ionic systems. This could be reasonably explained by assuming that permeability coefficient,
P, is proportional to partition coefficient.
6. The effect of the compositions of membrane as well as the concentration of external solution on the membrane potential was studied with the system, 10
-2 M NaCl CPC+CPX=5×10
-4 M10
-1-10
-3M NaX X=ClO
4-, SCN-, and Br-. When the composition of membrane was unaltered, the B. I. P. vs. concentration of external solution relationship was expressed with a constant value of
Kpot.X, Y. On the other hand,
Kpot.X, Y. showed strong dependence upon the composition of membrane mole fraction of CPC when it was altered.
7. It was pointed out that further studies on membrane permeability are necessary in order to elucidate the nature of
Kpot.XY.
抄録全体を表示