Study on separation of palladium by phase separation extraction in water-1-propanol-ammonium sulphate system

The phase separation and extraction of Pd (II) with water-1-propanol was investigated, as well as the separation conditions of Pd (II) from other metal ions. The results showed that the water-1-propanol solution could be divided into two phases in presence of ammonium sulphate. In this phase separation process, the association complex [PdBr₄^2-] [C₃H₇OH₂⁺]₂, which was formed by protonated 1-propanol (C₃H₇OH₂⁺) and PdBr₄^2-, could be fully extracted by 1-propanol. The extraction efficiency of Pd (II) was up to 96.7% at pH 2.0 when the concentrations of 1-propanol, potassium bromide and ammonium sulphate were 30% (V/V), 7.0×10^-3 mol/L and 0.2 g/mL, respectively. Under the same condition, other metal ions including Ag (I), Cu (II), Fe (III), V (V), Ni (II), W (VI), Al (III), Pb (II), Cr (III), U (VI), Mg (II) and Bi (III) were not extracted, realizing the separation of Pd (II) from these metal ions. This method was applied to the extraction separation and determination of Pd (II) in synthetic water and Pd-Ni electroplating solution with satisfactory results.