IMPREGNATED RESINS CONTAINING DI(2-ETHYLHEXYL) THIOPHOSPHORIC ACID FOR THE EXTRACTION OF PALLADIUM(II) - I - PREPARATION AND STUDY OF THE RETENTION AND DISTRIBUTION OF THE EXTRACTANT ON THE RESIN

Solvent impregnated resins containing di-(2-ethylhexyl) thiophosphoric acid(DEHTPA) were prepared by direct adsorption of the extractant ont o Amberlite XAD2 using a dry impregnation method. The impregnated resi ns were characterized by means of potentiometric titrations and specif ic surface area measurements, and a new method to determine DEHTPA con tent in the resin based on surface area measurements, is proposed. The distribution of DEHTPA between the aqueous phase and the resin phase was studied, and the data obtained have been treated by the program LE TAGROP-DISTR in order to determine the distribution constant K-D, the dimerization constant K-2 and the acidity constant K-a.