KBr-水-正丙醇体系中析相萃取分离富集Hg(Ⅱ)

Study on green extraction separation and enrichment of Hg(Ⅱ) in potassium bromide-water-n-Propyl Alcohol system by Phase separation

研究了KBr-水-正丙醇析相萃取Hg(Ⅱ)的行为及与一些金属离子分离的条件。结果表明,(NH4)2SO4能使正丙醇的水溶液分成两相,在分相过程中,Hg(Ⅱ)与KBr生成的HgBr42-与质子化正丙醇(C3H7OH2+)形成的缔合物[HgBr42-][C3H7OH2+]2能被正丙醇相完全萃取。当溶液中KBr、(NH4)2SO4和正丙醇的浓度分别为8.0×10-3mol/L、0.2 g/mL和30%(V/V)时,HgBr42-的萃取率达到97.3%以上,Co(II)、Mg(II)、Fe(III)、Cu(II)、Ni(II)、Ag(Ⅰ)、Al(III)、Bi(III)、Pb(II)、U(Ⅵ)、V(Ⅴ)、W(Ⅵ)和Cr(III)基本不被萃取,实现了Hg(Ⅱ)与上述金属离子的分离。该方法在微量汞的分离和富集分析中有实用价值。

The extraction and separation of Hg（Ⅱ） from other metal ions with potassium bromide-water-n-propyl alcohol system were studied.The results showed that the n-propyl alcohol-water could be well divided into two phases when ammonia sulfate was added.Hg（Ⅱ）could react with potassium bromide to form [HgBr42-][C3H7OH2＋]2,and this associated complex could be completely extracted by n-propyl alcohol phase.When the system contained 8.0×10-3 mol/L potassium bromide,0.2g/mL ammonia sulfate and 30% n-propyl alcohol（V/V）,Hg（Ⅱ） was well separated from Co（II）,Mg（II）,Fe（III）,Cu（II）,Ni（II）,Ag（Ⅰ）,Al（III）,Bi（III）,Pb（II）,U（Ⅵ）,V（Ⅴ）,W（Ⅵ） and Cr（III）,and the extraction recoveries of Hg（Ⅱ） were over 97.3%.The developed method could be used to separate and concentrate trace level of mercury.