A STUDY OF 2-HEPTANONE AND 2-OCTANONE AS SOLVENTS FOR 2-PHASE ELECTROCHEMISTRY .2. FACILITATED ION TRANSFERS

Transition metal ion (Cd2+, Co2+, Cu2+, Mn2+, Ni2+, Zn2+) transfer fro m water to methyl n-amyl ketone (2-heptanone) and methyl n-hexyl keton e (2-octanone) facilitated by nitrogen-containing ligands has been inv estigated by a.c. and d.c. voltammetry. For Cd2+ Cu2+ and Zn2+ in the presence of terpyridine as a ligand both facilitated and complex ion t ransfers are observed, while for the Co2+- and Ni2+-terpyridine system s only complex ion transfer takes place. The differences between the f acilitated and complex ion transfers have been discussed in terms of t he different mechanisms of the transfer reactions. This study shows th at it is possible to use 2-heptanone and 2-octanone in electro-assiste d solvent extraction and supported liquid membrane separation of metal ions, based on two-phase electrochemical principles. (C) 1997 Elsevie r Science S.A.