M. Rovira et al., Selective liquid-liquid extraction of palladium(II) from hydrochloric acidmedia by di-(2-ethylhexyl) thiophosphoric acid (DEHTPA), SOLVENT EXT, 17(2), 1999, pp. 333-349
Liquid-liquid extraction of Pd(II) from hydrochloric acid solutions using d
i-(2-ethylhexyl) thiophosphoric acid (DEHTPA or HL) dissolved in kerosene h
as been studied. The distribution equilibrium of DEHTPA between the aqueous
phase and the organic phase was investigated by treating the data with the
computer program LETAGROP-DISTR. The extraction of Pd(II) from HCl solutio
ns by DEHTPA was studied as a function of several variables: equilibration
time, organic phase diluent, HCl and DEHTPA concentrations as well as tempe
rature. Experimental equilibrium data were analyzed numerically using the p
rogram LETAGROP-DISTR and the results showed that Pd(II) extraction can be
explained assuming the formation of PdL2 complexes in the organic phase. DE
HTPA was found to be selective for Pd(II) against Pt(IV), Rh(III), Cu(II),
Fe(III) and Zn(II). The back-extraction of Pd(II) loaded in the organic pha
se using different stripping reagents is also reported.