A chelating resin is an important polymer which removes transition metal ions from aqueous solutions. For this purpose, various types of multidentate ligands have been introduced into a network polymer. Although these chelating resins take up almost all transition metal ions in high yield, they do not meet an important industrial process: that is, to remove a particular metal ion from aqueous solutions containing various metal ions. These chelating resins do not have sufficient selectivity of metal ion. In the reported experiments, poly(4-vinylpyridine) (PVP) was crosslinked with 1,4-dibromobutane with a metal ion as template. The adsorption behavior of copper, cobalt, zinc, and cadmium ions on the obtained resin (DBQP) was studied. The DBQP resin prepared with a metal ion as template preferentially adsorbed the metal ion used as template. The stability constant of the copper complex of DBQP was largest for the DBQP resin prepared with a copper ion as template, which was due to its large entropy change for the complexation.
