Abstraet---Ethylenediamine (EDA) is adsorbed from aqueous solution on Na-, Kand Li-montmorillonite as the monoprotonated cation (EDAH +) through an ion-exchange process. On washing with distilled water the second amine function is protonated--probably through dissocmtion of water near the clay surface--and simultaneously formed alkali hydroxide is removed. In air-dried clay films, prepared from...