The ideal Donnan potential of an ionized polyelectrolyte medium is shown to be an approximate solution to a system of Poisson-Boltzmann (PB) equations for a periodic array of charged plates in an electrolyte bath. This result, derived using homogenization and scaling methods, demonstrates that the macrocontinuum, thermodynamic Donnan, and statistical mechanical PB models describe the same pheno...

Membrane potentials of polysulfonated cation exchange membranes (unsupported polysulfone, SA3S and polyester supported polysulfone, SA3T) for KCl, NaCl and LiCl solutions using Ag/AgCl electrodes were measured. The measurements were carried out for, KCl SA3S or SA3T MCL, (M: K, Na and Li) systems. The concentration of salt (KCl) was kept constant in one side of the cell, C1, at 1.10 M was chang...

Fouling of membrane surfaces by particulate matter and large organic molecules is relatively common for pressure-driven membrane processes, namely, reverse osmosis (RO), nanofiltration (NF), and ultrafiltration (UF). Donnan membrane process (DMP) or Donnan Dialysis is driven by electrochemical potential gradient across a semipermeable ion exchange membrane. Theoretically, DMP is not susceptible...

1. A comparative study has been made of the diffusibility of calcium in solutions of crystalline egg albumin, serum globulin, and human blood serum. 2. In all three of these solutions, at pH 7.4, molal Ca concentrations within the membrane are greater than the calcium concentrations in the outside solutions, quite in accordance with the Donnan theory. 3. At pH 7.4, the ratio of See PDF for Stru...

Knowledge of location and magnitude of charge density, together with the pore morphology allows one to calculate the Donnan potential, characterizing ion exclusion in charged porous materials. Use of the electro-chemical potential together with Gauss’ electrostatic theorem allows the computation of the ion and voltage distribution at the microscale. On the other hand, commonly used macroscopic ...

It has been suggested that potentials measured with conventional microelectrodes in chemically or mechanically skinned muscle fibers arise from a Donnan equilibrium due to myofilament fixed charges. This hypothesis was tested in mechanically skinned frog (Rana pipiens) semitendinosus fibers by measuring the distribution potential (Ed) between fiber and bath with 3 M KCl-filled microelectrodes a...

reference electrode (3). The ionized calcium concentration of sequential retentates prepared by ultrafiltration of a human control serum increased with increasing protein concentration in a way consistent with Donnan theory (4, 5) when the analyzers’ standard reference-electrode liquid junctionswere used; however, the ionized calcium in the same retentates declined slightly with increasing prot...

The streaming potentials of two different nanofiltration membranes were studied with several electrolyte solutions to investigate the influence of salt type and concentration on the zeta potential and kinetic surface charge density of the membranes. The zeta potentials decreased with increasing salt concentration, whereas the kinetic surface charge densities increased. The kinetic surface charg...