Metal uptake by porous iminobis (N-2-aminoethylacetamide)-modified polysiloxane ligand system

Abstract

A porous solid iminobis(N-2-aminoethylacetamide) polysiloxane ligand system of the general formula P–(CH2)3–N(CH2CONHCH2CH2NH2)2, (where P represents [Si–O]n siloxane network) has been prepared by modification of immobilized diethyliminidiacetate P–(CH2)3N(CH2CO2Et)2 with ethylenediamine in toluene. The new modified polysiloxane system exhibits high potential for the uptake of metal ions (Mn2+, Fe3+, Co2+, Ni2+, Cu2+ and Zn2+). This ligand system shows higher capacity toward the metal ions than its parent iminiodiacetate precursor. Complexation of ligand system for the metal ions at the optimum conditions was found in the order: Cu2+ > Fe3+ > Ni2+ > Co2+ > Mn2+ > Zn2+. Stability studies of the immobilized ligand system show that a degradation of the siloxane network and leaching of some species occurred upon treatment with acid or basic aqueous solutions in addition to metal ion …