Liquid membranes made of chlorinated hydrocarbons and containing the macrocyclic polyether dibenzo-18-crown-6 can separate potassium nitrate from aqueous solutions of mixed sodium nitrate, potassium chloride and other salts. Experiments with the Schulman bridge show that this separation occurs because the membrane facilitates transport of complexed potassium nitrate ion pairs. Experiments with emulsion liquid membranes show that this separation has commercial potential.
Bibliographical noteFunding Information:
Zhang Qi is grateful to the Academia Sinica of the People’s Republic of China for a research fellowship. Major support for this research came from the National Science Foundation grants CPE 8207917 and CPE 8025304; other support came from the Department of Defence grant DAAG 29081-K099.