PERMEATION OF NEODYMIUM AND PRASEODYMIUM THROUGH SUPPORTED LIQUID MEMBRANES CONTAINING DI-(2-ETHYLHEXYL)PHOSPHORIC ACID AS A CARRIER

Transport of Pr(III) and Nd(III) cations between nitrate feed and 0.1 mol/I nitric acid strip solutions through a supported liquid membrane has been studied as a function of both the stirring rate and the chemical composition of the system. The liquid membrane consisted of di- (2-ethylhexyl)phosphoric acid (DEHPA) in kerosene immobilized on a porous di-fluoropolyvinylene laminar support. Reuse of the membrane has been investigated. However, good results were obtained only by reimpregnating of the support. Metal permeability increases sharply with carrier concentration up to 0.1 mol/I DEHPA and thereafter becomes almost independent of carrier concentration. The dependence of permeability coefficient, P, vs. feed pH, measured at low carrier concentration, exhibit maxima at a pH of ca. 3. The values for the membrane separation factor, alpha = P(Nd)/P(Pr), of 1.25 and 1.5 have been determined at pH 2.7 and 2.5, respectively.