Donnan equilibrium revisited: Coupling between ion concentrations, osmotic pressure, and donnan potential

This paper discusses the little-known fact that Donnan’s equilibrium criteria established over 100 years ago neglected coupling between ion concentrations and osmotic pressure. Such can be treated based on general thermodynamic considerations including solvent equilibrium, leading to a membrane potential consists of not only classical Donnan term but also an additional due pressure, existence even when impermeable species are charged. coupled treatment conflicts with well-established Poisson–Boltzmann equation Nernst–Planck equation, is consistent extension these equations effects by Freise Schlogl, enables us view electrical double layer as equilibrium.