The process of separating a selected ion from a plurality of other ions in a multiple ion solution by contacting the solution with a macrocyclic ligand bonded to silica which selectively complexes with the desired ion

DETAILED DESCRIPTION The compounds of the present invention comprise certain macrocyclic ligands covalently bonded to silica, e.
g.
, sand or silica gel.
The compounds are identified above.
The process of the present invention uses the compounds, which are characterized by high selectivity for and removal of desired metal ions or groups of metal ions present at low concentrations from the source phase containing a mixture of metal ions with the ions one does not desire to remove present in much greater concentrations in the solution, in a separation device such as a column through which the solution is flowed.
The process of selectively removing and concentrating the desired ion(s) is characterized by the ability to quantitatively complex from a large volume of solution the desired ion(s) when they are present at low concentrations.
The said ions are recovered from the separation column by flowing through it a small volume of a receiving phase which contains a solubilized reagent which need not be selective, but which will strip the ions from the macrocyclic ligand quantitatively.
The recovery of the desired metal ions from the receiving phase is easily accomplished by well known procedures.