Compositions and methods for selectively binding metal ions from source solutions are disclosed. The composition is comprised of a polyamide-containing ligand covalently bonded to a particulate solid support through a hydrophilic spacer having the formula SS--A--X--L. In this formula, SS is a particulate solid support such as silica or a polymeric bead, A is a covalent linkage mechanism, X is a hydrophilic spacer grouping, and L is a polyamide-containing ligand having three or more amide groups and two or more amine nitrogens separated by at least two carbons with the proviso that when SS is a particulate organic polymer, A--X may be combined as a single covalent linkage. The separation is accomplished by passing a source solution containing the ions to be separated through a column containing the particulate composition, causing the selected ions to be complexed to the polyamide-containing ligands, and subsequently removing the selected ions from the column by passing an aqueous receiving solution through the column and quantitatively stripping the selected ions from the polyamide-containing ligand.