INFLUENCE OF AMMONIUM ON NAFION _ 117 MEMBRANES

摘要

The ion exchange equilibrium of ammonium between an aqueous phase and Na .on _ 117 were measured at 10.0,25.0,40.0,and 60.0℃ by equilibrating the membrane in 0.1000 M chloride electrolytes of known cation composition. The water content in the membrane phase was found to decrease linearly with the cation fraction of ammonium in the membrane phase (y NH_(+4)) from ee H_2 O =21. 2 (moles of water per mole sufonic acid groups) in proton form Na .on _ in pure water to ee H_2 O=13.2 in ammonium form Na .on _ in a 0.1 M chloride solution. The conductivity was measured by impedance in a two-electrode set- up using a stack of membranes. The conductivity was also found to decrease linearly with y NH_(+4) from 97 mS/cm to 25 mS/cm at 25.0℃. The temperature dependence of the conductivity was measured, and the .tted activation energy in an Arrhenius-type equation was found to depend on membrane composition,E_a=10 .3+4 .2 • y NH_(+4)[kJ/mole].