Infrared spectroscopic analysis of the extraction mechanisms of metals with inverted micelle systems

Liquid-liquid extraction is widely used to extract and/or to concentrate he avy metals from aqueous solutions in analytical chemistry as well as in ind ustry. During this process the cations present in aqueous solution are extr acted by ion exchange into an organic phase containing an extracting agent. Once this step is accomplished, the organic phase loaded with cations is c ollected by decantation and exposed to a small volume of a strongly acidic aqueous solution. Due to the extracting agent protonation, the cations are released from the organic phase into the aqueous acid phase and the extract ing agent can be recycled for further extractions. IR spectroscopy investig ations have shown that the efficiency and the speed of exchange are governe d by water. An extraction model is proposed.