Irreversible thermodynamic model equations of the transport across a horizontally mounted membrane.

The Kedem-Katchalsky-Zelman model equations for transmembrane transport in multicomponent, non-ionic and heterogeneous solutions have been modified. The validity of this model for binary and ternary solutions was verified, using a cell with a horizontally mounted membrane. In the cell, volume and solute fluxes were measured as a function of gravitational configuration. In the experimental set-up, water was placed on one side of the membrane. The opposite side of the membrane was exposed to aqueous solutions of densities greater than that of water, aqueous ethanol (less dense than water) or glucose/ethanol/water solutions. The experimental results presented herein illustrate pseudo-phase transitions which occur from a non-convectional to convectional state or in the reverse direction.