Kinetics of Heavy Metal Extraction by Diazadibenzo Crown Ethers at the Water/ 1,2-Dichloroethane Interface. Electrochemical Study

In this study, the kinetics of the facilitated transfer of Pb2+, Cd2+, and Zn2+ by a new diazadibenzo crown ether (DB, diazadibenzo-18-crown-6, diazadi (t-butylbenzo)-18-crown-6, and diazadibenzo-15-crown-5) across the water|1,2-dichloroethane interface was studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy. The experiments were performed using a two-electrode cell configuration. The electrochemical impedance spectroscopy results showed that the values for the rate constant were in the order of 10-3 cm s-1, depending on the metal in combination with the ligand structure. The experiments made it possible to understand the ionophoretic ability of the DB ligands to transport ionic metals across the water|1,2-dichloroethane interface. The chemical structure of the DB plays an important role in ion selectivity and kinetic values. This study contributes toward a better understanding of the transfer of heavy metals within biological cells.