Metal ion extraction using newly-synthesized bipyridine derivative as a chelating reagent in supercritical CO(2).

4,4'-Bis(dihexylaminocarbonyl)-2,2'-bipyridine (BDC-Bipy) was synthesized and studied systematically as a chelating reagent for metal ions extraction in supercritical CO(2). The compound showed high extraction efficiency for Co(2+) (100%), Cu(2+) (100%), Cd(2+) (98.2%), and Zn(2+) (100%) ions and good extraction efficiency for Sr(2+) (79.4%) and Pb(2+) (89.8%) when the extraction was performed in supercritical CO(2) at 313 K and 25 MPa with the system of BDC-Bipy, deionized water and perfluoro-1-octanesulfonic acid tetraethylammonium salt. The recoveries of mixed metal ions were also measured; unfortunately, the system of extraction has no selectivity for the metal ions.