Facilitated transport of hydrophilic salts by mixtures of anion and cationcarriers and by ditopic carriers

Anion transfer to the membrane phase affects the extraction efficiency of s alt transport by cation carriers 1 and 3. Addition of anion receptors 5 or 6 to cation carriers 1, 3, or 3 in the membrane phase enhances the transpor t of salts under conditions in which the cation carriers alone do not trans port salt. The extraction of salt by the carrier mixtures is larger than by cation or anion carrier only, but the rate of diffusion is lower. Ditopic receptors 8 and 9 transport CsCl or KCl much faster than monotopic anion re ceptor 7 or cation receptors 1 and 2. The faster transport is due to a high er extraction constant K-ex despite a lower diffusion constant of the ditop ic salt complex.