Metal Ion Extraction Using Newly-synthesized Bipyridine Derivative as a Chelating Reagent in Supercritical CO₂

Abstract

4,4′-Bis(dihexylaminocarbonyl)-2,2′-bipyridine (BDC-Bipy) was synthesized and studied systematically as a chelating reagent for metal ions extraction in supercritical CO₂. The compound showed high extraction efficiency for Co²⁺ (100%), Cu²⁺ (100%), Cd²⁺ (98.2%), and Zn²⁺ (100%) ions and good extraction efficiency for Sr²⁺ (79.4%) and Pb²⁺ (89.8%) when the extraction was performed in supercritical CO₂ 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.