Selectivity of phenol-formaldehyde resins and separation of rare alkali metals

The sorption capacity and selectivity of the chemically stable, macroporous phenol-formaldehyde resins with phenolic ion-exchange groups only, towards alkali metal ions have been studied. The selectivity of these resins towar ds rubidium and cesium ions were found to be significantly greater than tha t of the sulfonic, carboxylic, phosphonic, nitrated sulfonic and sulfonic-p henolic ion-exchange resins. The contributions of the ion-exchange and mole cular sorption mechanisms to the sorption capacity and the selectivity were determined. The synergetic action of the phenolic active groups on the pro perties of ion-exchange resins is discussed. The resins with phenolic ion-e xchange groups only were found to be very efficient for separation of the r are alkali metal ions. (C) 1998 Elsevier Science B.V. All rights reserved.