Adsorption of palladium(II) from hydrochloric acid solutions using polymeric resins impregnated with novel N-substituted 2-(diphenylthiophosphoryl)acetamides

Novel N-substituted 2-(diphenylthiophosphoryl)acetamides ligands containing pyridine and quinoline fragments, were synthesized and studied as extractants for Pd(II) ions from HCl solutions. The introduction of a pyridine and a quinoline fragments into 2-diphenylthiophosphorylacetamide molecule resulted in a considerable increase of the efficiency of Pd(II) extraction. The influence of aqueous and organic phases on the extraction efficiency was elucidated and stoichiometry of the complexes extracted was determined. Polymeric macroporous resins XAD-7 HP impregnated with these ligands were prepared and used as sorbents for recovery and preconcentration of Pd(II) from hydrochloric acid solutions. The efficiency of the Pd(II) adsorption decreases as the concentration of the hydrochloric acid in the aqueous phase grows. The process of Pd(II) adsorption is endothermic, spontaneous and follows a pseudo-second-order kinetic model. The equilibrium data can be well fitted using the Langmuir isotherm model and the Pd(II) adsorption capacity was found to reach 52.77 mg g−1. The potentialities of macroporous resins XAD-7 HP impregnated with N-substituted 2-(diphenylthiophosphoryl)acetamides ligands for the effective separation of Pd(II) from secondary resources are demonstrated.