[Thermodynamical description of the concentration polarization in a membrane transport of non-electrolyte solution].

An expression for concentration polarization coefficient (chi) was derived from Kedem-Katchalsky equations. This expression contains the volume flux (Jvm), transport parameters of a membrane (omega m) and concentration boundary layers (omega 1, omega h). Calculations performed using the obtained expression showed that for a polymeric membrane with fixed transport properties, coefficient chi is a nonlinear function of concentration difference of solutions. This nonlinearity is related to the appearance of the convection instability that breaks symmetry of the l(h)/M/l(l) complex in relation to the gravitational direction.