Student Summer Scholars


Electrochemical Investigation of Facilitated Terbium (III) Ion-Transfer at Micro-Liquid/Liquid Interfaces

First Advisor

Scott Thorgaard


electrochemistry, ion transfer, microelectrode, voltammetry, ITIES, ionophore, terbium



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Facilitated ion transfer (FIT) occurs when transport of an ion between two phases is enhanced by complexation with a receptor molecule. FIT is applied in technologies including ion sensing and removal of harmful ions from waste.1 Here, electrochemistry at the interface between two immiscible electrolyte solutions (ITIES) was used to study FIT. FIT of K+ by dibenzo-18-crown-6 (DB18C6)2,5 and FIT of Tb3+ by a tripodal carbamoylmethylphosphine oxide ligand (TREN-CMPO-OEt) were characterized using cyclic voltammetry at water/1,2-dichloroethane (DCE) micro-interfaces. The Tomeš criterion measured in steady state voltammograms were 75.4 mV and 45.2 mV for the K+–DB18C6 and Tb3+–TREN-CMPO-OEt transfers, respectively, consistent with reversible or quasi-reversible binding of the two ions. The binding constant for the K+–DB18C6 complex in DCE was measured to be 1.6 × 1010. Future work will include screening of organic ligands for their ability to bind Tb3+ and investigation of unassisted Tb3+ transfer.