Studies on synergistic extraction of Pd (II) using thiosemicarbazone derivative of 2-OHʹ naphthaldehyde and neutral donors

Abstract

The synergistic extraction of Pd(II) from aqueous hydrochloric acid medium, using thi osemicarbazone derivative of 2-OHʹ naphthaldehyde in ethyl acetate has been investigated in the presence of various neutral donors like amines (TOA, Amberlite LA-2 and Adogen-464) and phosphorus oxides (TOPO, phosphonate, TBPO, TPPO and TBP). The overall equilibrium constant (log <i>K) </i>for the ternary species [Pd(A)CIS], where S is donor and A is the ligand, has been calculated for various systems. The values of synergistic co-efficient and adduct formation constant in organic phase (β) for the amine donors are found to be greater than those for the phosphorus oxide donors. Among the amines, the trend is found to be quarternary> tertiary> secondary and among the phosphorus oxide donors, it is phosphonate > trioctyl phosphine oxide (TOPO) > tributyl phosphine oxide (TBPO) > triphenyl phosphine oxide (TPPO) >tributyl phosphate (TBP). Effects of <i>p</i>H variation and nature of various diluents on the synergistic extraction of Pd (II) have also been studied. The procedure has been applied to the estimation of Pd (II) in rock samples.