水-正丙醇-硫酸铵体系析相萃取分离钯的研究

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

研究了水-正丙醇析相萃取Pd(Ⅱ)的行为及Pd(Ⅱ)与一些金属离子分离的条件。结果表明,硫酸铵能使正丙醇的水溶液分成两相,在分相过程中,Pd(Ⅱ)与溴化钾生成的PdBr42-与质子化正丙醇(C3H7OH2+)形成缔合物[PdBr42-][C3H7OH2+]2能被正丙醇相完全萃取。当溶液中正丙醇的体积分数、溴化钾浓度和硫酸铵的质量浓度分别为30%,7.0×10-3mol/L,0.2 g/mL且pH2.0时,Pd(Ⅱ)的萃取率达到96.7%以上,而Ag(Ⅰ)、Cu(Ⅱ)、Fe(Ⅲ)、V(、Ni(Ⅱ)、W(Ⅵ)、Al(Ⅲ)、Pb(Ⅱ)、Cr(Ⅲ)、U(Ⅵ)、Mg(Ⅱ)、Bi(Ⅲ)基本不被萃取,实现了Pd(Ⅱ)与上述金属离子的分离。对合成水样和钯镍电镀液中的钯进行了定量萃取分离和测定,获得了满意结果。

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 [PdBr42-][C3H7OH2＋]2,which was formed by protonated 1-propanol（C3H7OH2＋） and PdBr42-,could be fully extracted by 1-propanol.The extraction efficiency of Pd  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  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.