OSMOTIC EFFECTS AT THE MASS-TRANSPORT THROUGH LIQUID MEMBRANES

The water transport through the membrane of a stable w/o/w-emulsion has been investigated. It has been found that the surfactant SPAN 80, which is added to the emulsion as a stabilizing agent, is a good carrier for water molecules. The water transport from the outer water phase through the organic membrane phase into the inner water phase causes swelling of the emulsion and therefore several properties of the emulsion are changed. An admixture of various carriers to the membrane phase showed that nitrogen containing agents have less influence on the water transport than oxygen containing agents. Organic phosphoric or carboxylic acids enhance the water transport whereas emulsions containing anion exchangers (like ALIQUAT 336) show an almost ideal behavior: the water transport by SPAN 80-molecules is prevented without affecting the properties of the carrier.