IONIC TRANSPORT IN A CONTINUOUS DONNAN DIALYZER WITH A PARALLEL PLATE CHANNEL AND AN AGITATED TANK

Ionic transport in a continuous Donnan dialyzer with a parallel-plate channel and an agitated tank was studied for a bi-ionic exchange system. A theoretical model of the system was formulated on the basis of diffusion equations in terms of diffusion, migration and convection of each ion. Theoretical solutions were obtained by numerical calculations using a finite-difference technique. Simultaneously, continuous Donnan dialytic experiments were conducted for the K + -H+ exchange system with a cation-exchange membrane. The validity of this model was confirmed by comparison with experimental results for mean dialytic rates. The numerical calculation also provided distributions of ionic concentrations and the electric potential in the parallel-plate channel. An effectiveness factor was introduced to discuss the proportion of the mass transfer resistance in the membrane phase to the overall mass transfer resistance. The influence of Reynolds number and channel height on the mean dialytic rates and the effectiveness factor was also examined.