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Chemistry

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Analytical Chemistry

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Introduction to Separation Methods

Chelate Extraction for Metal Ion Separation

Description

Chelate extraction is a way to separate metal ions by using an organic ligand, or chelating agent, to form an uncharged metal complex. The chelating agent needs hydrophobic groups, and it must act as a weak acid so it can lose a proton and bind to the metal.

Most organic ligands used for this met...

Transcript

金属离子可通过与有机配体络合形成不带电荷的螯合物而实现分离。

螯合剂必须含有疏水基团,并表现为弱酸,通过失去一个质子与金属结合。

金属-配体配合物在水相中形成,并被萃取到有机相中。

当使用大量过量的络合试剂时,金属络合物的分配系数仅取决于水相的 pH 值。

考虑铜(II)和铅(II)离子的萃取效率随pH变化的曲线图。

当水相 pH 值小于 5 时,铜可被定量萃取到有机相中。

然后,可将 pH 缓冲至约 9.5,以实现铅的选择性萃取。

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