DIAION™ CR20 has a polyamine group as a chelating ligand which is bonded onto a highly porous crosslinked polystyrene matrix. DIAION™ CR20 shows a large affinity for transition metal ions but does not adsorb alkali, alkaline earth, and Sn, Zr, Th, Al, Fe(II) ions.
The selectivity order of DIAION™ CR11 for metal ions is as follows:
Hg2+ > Fe3+ > Cu2+ > Zn2+ > Cd2+ > Ni2+ > Co2+ > Ag+ > Mn2+
Adsorbed metal ions can be eluted with an acid, and the resin can be reused after regeneration with caustic alkali.