Structural characterization of immobilized-polysiloxane iminobis(N-diethylenediamineacetamide) ligand system

Abstract

Insoluble porous solid polysiloxane immobilized ligand system bearing chelating ligand group of the general formula P(CH 2) 3N[CH 2CONH(CH 2) 2NH(CH 2) 2NH 2] 2 (where P represents [SiO] n polysiloxane network) has been prepared by the reaction between the polysiloxane immobilized diethyliminodiacetate ligand system, P(CH 2) 3N(CH 2CO 2Et) 2 and diethylenetriamine in toluene. The XPS and FTIR results showed that all ethylacetate groups (COOEt) are converted into the amide groups (NCO). The new functionalized ligand system exhibits high capacity for the uptake of the metal ions (Mn 2+, Fe 3+, Co 2+, Ni 2+, Cu 2+ and Zn 2+). Complexation of the prepared ligand system for these metal ions at the optimum conditions was found in the order: Cu 2+>Ni 2+>Fe 3+>Co 2+>Mn 2+>Zn 2+. This ligand system shows higher capacity toward the metal ions than its iminiodiactate precursor which we have been reported. Stability studies of the immobilized ligand system show high degradation of the siloxane network and leaching of some species upon treatment with strong acidic or basic aqueous solutions in addition to metal ion solutions. Minimum leaching was observed at pH 6–8.