[Relation between effective and real solute permeability coefficients through polymeric membrane].

Using Kedem-Katchalsky thermodynamic formalism the mathematical model describing relation between effective and real solute permeability coefficients through a membrane was elaborated. The relation is described by parameter 4, which is the quotient of these coefficients. Calculations performed on the basis of obtained quadratic equation show that for a polymeric membrane with fixed transport properties parameter zeta s is nonlinear function of solution concentration. The value of this parameter can express the distance between a system and stable diffusion state. Appearance of unstability related with breaking symmetry of concentration boundary layers towards the gravitation direction causes increase of the coefficient value. This is the sign of appearance of diffusion-convection of mass transport.