Abstract: The process of the invention comprises removing and concentrating certain ions, such as the transition metal ions, from solutions thereof admixed with other ions which may be present in much higher concentrations by forming a complex of the desired ion(s) with a compound ##STR1## B and D are each a radical selected from the group of N(R.sup.3), N(R.sup.3)CH.sub.2, O, OCH.sub.2, S and SCH.sub.2, but B or D must be N(R.sup.3) or N(R.sup.3)CH.sub.2 ; E is a radical selected from the group consisting of H, NH(R.sup.3), SH, OH, lower alkyl, and Y and Z are radicals selected from the group of Cl, OCH.sub.3, OC.sub.2 H.sub.5, methyl, ethyl and halogenated substituents thereof, and O-matrix; R.sup.1 is a radical selected from the group consisting of H, SH, OH, lower alkyl and aryl such as phenyl, naphthyl and pyridyl; R.sup.2 is a radical selected from the group consisting of H or lower alkyl; R.sup.