Method for separating metal ions

Abstract

A method for separating metal ions, which comprises adding a selective capturing agent to an aqueous solution containing plural types of metal ions, said selective capturing agent being a cyclic compound and forming a complex with metal ions having ion radii suitable for the size of the ring alone, so that unnecessary metal ions are held by the selective capturing agent in the aqueous solution, and bringing said aqueous solution into contact with an ion exchange solid phase so as to transport desired metal ions alone to the solid phase.

What is claimed is:  
     
         1 . A method for separating metal ions, which comprises adding a selective capturing agent to an aqueous solution containing plural types of metal ions, said selective capturing agent being a cyclic compound and forming a complex with metal ions having ion radii suitable for the size of the ring alone, so that unnecessary metal ions are held by the selective capturing agent in the aqueous solution, and bringing said aqueous solution into contact with an ion exchange solid phase so as to transport desired metal ions alone to the solid phase.  
     
     
         2 . The method for separating metal ions according to  claim 1 , wherein the plural types of metal ions are in the same Group.  
     
     
         3 . The method for separating metal ions according to  claim 2 , wherein the plural types of metal ions are at least two types belonging to alkaline earth metal ions.  
     
     
         4 . The method for separating metal ions according to  claim 1 , wherein the selective capturing agent is a cryptand or a crown ether.  
     
     
         5 . The method for separating metal ions according to  claim 2 , wherein the selective capturing agent is a cryptand or a crown ether.  
     
     
         6 . The method for separating metal ions according to  claim 3 , wherein the selective capturing agent is a cryptand or a crown ether.