Study of extraction of Zn (II) from ammoniacal media with ionic liquids

In this paper a systematic study on liquid-liquid extraction of Zn (II) from ammoniacal media using ionic liquids (IL) as extractants is presented. The ionic liquids used for this study were: trihexyl(tetradecyl)-phophonium chloride (Cy IL 101), bis trihexyl(tetradecyl)-phophonium-(trifluoromethylsulfonyl) imide (Cy IL 109) and 1-octyl bromide pyridinium (1-BOP). With bis trihexyl(tetradecyl)- phophonium-(trifluoromethylsulfonyl) imide (Cy IL 109), the efficiency of the liquid-liquid extraction system was evaluated as a function of the nature of the aqueous phase (HCl, H2SO4 and NH4/NH3), the pH, the diluents nature (kerosene, tributyl phosphate and toluene), and the modifier content. The results showed a very fast kinetic of the Zn(II) transfer to the organic phase, reaching the equilibrium within 10 minutes of contact between the phases (organic/aqueous). On the other hand, the Zn(II) extraction was better (percentage of extraction 98% at pH 9.2), when it was extracted from NH+4/NH−3 media with an organic phase composed by Cy IL 109 dissolved in kerosene with 50% of decanol. The results showed that the uses of ILs in the extraction of metals ions, instead of organic solvents, in the liquid-liquid extraction processes are ecologically viable alternatives that require further study for its application.