Selective extraction of palladium(II) from hydrochloric acid solutions with pyridinecarboxamides and ACORGA®CLX50

The selectivity of Pd(II) extraction over Pt(IV), Pb(II), Cu(II) and Fe(III) with N-dodecylpyridine-3-carboxamide (3-C12) and N-dodecylpyridine-4-carboxamide (4-C12) is very high, compared with the commercial chelating extractant ACORGA®CLX50; therefore, these pyridinecarboxamides can be considered as effective extractants for Pd(II) separation from hydrochloric acid solutions. Over 90% of palladium(II) can be effectively extracted with 3-C12 and 4-C12 in the presence of Pb(II), Cu(II) or Fe(III) over the studied HCl concentration range. While merely up to 5% of the other metal is transported to the organic phase. Pd(II) can be separated from Pt(IV) efficiently at low HCl concentration. ACORGA®CLX50 indicates a much lower extraction than do pyridinecarboxamides in the same time range. The effect of the presence of NaCl is negligible. Extraction in a system with addition of NaCl is slightly lower than without the electrolyte.