Diglycolamide Based Mono and Di-Ionic Liquids Having Imidazolium Cation for Effective Extraction and Separation of Pb(II) and Co(II)

Two glycolamide based functionalized ionic liquids (ILs) having imidazolium cations namely LI (mono-ionic) and LII (di-ionic) were synthesized for the extraction of Pb(II) and Co(II) from waste water. The synthesized ligands were characterized by FTIR and NMR spectroscopy. The extraction efficiency of both mono- and di-ionic liquids was evaluated in terms of contact time, pH of the aqueous phase and metal ion concentration. The metal extraction was carried out at various pH values viz. 2, 4, 6, 8, and 10 whereas, at contact time of 15, 30, 45, 60, and 75 minutes. The optimized pH of 4 and equilibration time of 75 minutes was further utilized for extraction at various metal ions concentration (50, 100, 150, 200, and 250 ppm). LI exhibited low equilibration time as compared to LII whereas, both ligands showed maximum extraction at a pH of 4. A very high extraction efficiency of up to 99% for both metals was observed with LI and LII under optimized conditions. In addition to that effective separation of Co(II) and Pb(II) was observed at pH 10.