LIQUID LIQUID EXTRACTION AND BULK LIQUID MEMBRANE TRANSPORT OF TRANSITION METAL IONS (Fe3+, Co2+, Ni2+, Cu2+, Zn2+) USING HEXADENTATE SCHIFF BASE

Abstract

A hexadentate Schiff base N, N’-Bis[2-(salicylidene amino)]ethane-1,2-diamine (TTS) has been synthesized by condensation reaction of salicylaldehyde with triethylenetetramine (TETA) in ethanol and characterized by TLC, M.P., spectral analysis and mass spectrometry. This Schiff base membrane transport studies of transition metal ions (Fe3+, Co2+, Ni2+, Cu2+, Zn2+). The effect of metal ion concentration variation on extraction and transport is studied. The observed trend for extraction and transport of transition metal ions using Schiff base (TTS) is Cu2+> Fe3+> Co2+> Zn2+ ᴝ Ni2+ and Zn2+> Fe3+> Ni2+> Co2+ ᴝ Cu2+ respectively. The result of extraction study shows that TTS has highest extraction efficiency for Cu2+ metal ions followed by Fe3+, Co2+, Zn2+ and Ni2+ metal ions. This can be explained on the basis of cavity fit concept, size and charge density of metal ions and Pearson’s HSAB concept. The results of extraction and transport studies reveals that in general the TTS has high extraction efficiency as compared to that of transport, this may be due to TTS adopts a cis conformation with both arms at the same side, which leads to a better predisposed ionophore for metal complexation by bringing the nitrogen and oxygen donor sets closer proximity and form pseudo cavity.