Abstract
The possible use of 2-Mercaptopyridine N-oxide (HSPyO) as an extractant in ionic liquid chelate extraction was investigated with using several divalent metals (M2+, M = Cu, Ni, Zn, Cd and Mn). The extraction performance of HSPyO in the 1-buthyl-3-methyimidazolium bis(trifluoromethanesulfonyl)imide (C4mimTf2N) system was very similar to that in the chloroform system, except for Cd2+. Over wide pH range, Cu2+, Ni2+ and Zn2+ were extracted quantitatively into C4mimTf2N as neutral 1:2 complexes M(SPyO)2. Furthermore, the strange extraction behavior for Cd2+ into C4mimTf2N was found to originate in the competitive extraction of neutral Cd(SPyO)2 and anionic Cd(SPyO)3–.
