Facilitated Transport

Synonyms

Assisted transport

Transport mechanism used to improve flux, permeability, and selectivity in separations by liquid membranes. Mass transport selectivity and transfer velocity in a liquid membrane are mainly determined by the solubility and the diffusion coefficient in the membrane phase of the component to be separated. The driving force of the transport process is the gradient of chemical potential, normally due to a concentration gradient between the feed and the product phases. Then, a component which is soluble in the membrane phase and whose concentration is different at both sides of that membrane phase will be transported through it (Fig. 1a). The component does not react chemically in the liquid membrane, and then it remains in the same chemical form in the feed, in the membrane, and in the product phases. Transport will end when an equality of concentration of the component prevails on both sides of the membrane phase. In order to improve the effectiveness of the...