聚乙二醇-硫酸铵-亚硝基R盐体系中钴(Ⅱ)的分离及其存在形态

Study on the Separation and Existing Form of Cobalt(Ⅱ) by Polyethylene Glycol-Ammonium Sulfate-Nitroso-R-Salt System

在 ｐＨ ４．０～６．０的 ＨＡｃ－ＮａＡｃ缓冲溶液中，Ｃｏ（Ⅱ）、Ｆｅ（Ⅲ）、Ｎｉ（Ⅱ）、Ｃｕ（Ⅱ）等金属离子与亚硝基Ｒ盐可形成稳定络合物。加入ＨＣＩ适当提高溶液酸度（ＨＣＩ浓度在０．３～０．６ｍｏｌ／Ｌ），用聚乙二醇２０００（ＰＥＧ）－硫酸铵－亚硝基Ｒ盐体系萃取，Ｃｏ（Ⅱ）可被ＰＥＧ相几乎完全萃取，而Ｆｅ（Ⅲ）、Ｎｉ（Ⅱ）、Ｃｕ（Ⅱ）基本上不被萃取。实现了Ｃｏ（Ⅱ）、Ｆｅ（Ⅲ）、Ｎｉ（Ⅱ）、Ｃｕ（Ⅱ）混合离子合成样品和硅酸盐岩矿实际样品中Ｃｏ（Ⅱ）的分离与测定。同时吸收光谱、摩尔比、连续浓度变换、加入表面活性剂等实验表明，在萃取相Ｃｏ（Ⅱ）与亚硝基Ｒ盐是１：３络阴离子形式存在的。

The stable complexes of Co(Ⅱ), Fe(Ⅲ) Ni(Ⅱ) and Cu(Ⅱ) ions with Nitroso-R-salt are formed in HAc-NaAc buffer solution. In 0 .3 - 0. 6 mol/L HCI medium, Co(Ⅱ) complex can be extracted by polyethylene glycol (PEG)-(NH4)2SO4-Nitroso-R-salt, but Fe(Ⅲ), Ni(Ⅱ) and Cu(Ⅱ) complexes can not be extracted. Experimental result shows that the complex of Co(Ⅱ) with Nitroso-R-salt is a complex anion of 1:3 in PEG phase. The method has been applied to quantitative separation and determination of Co(Ⅱ) from synthetic mixture of Co(Ⅱ), Fe(Ⅲ), Ni(Ⅱ) and Cu(Ⅱ) and silicate sample.