Uptake of divalent metal ions (Cu2+, Zn2+, and Cd2+) by polysiloxane immobilized diamine ligand system

Abstract

Porous solid siloxane polymers carrying diamine functional group of formula P–(CH2)3NH–CH2CH2NH2 (where P–represents a silica-like siloxane framework) have been prepared by replacement of the iodine in iodopolysiloxane with ethylenediamine. The iodofunctionalized polysiloxane was prepared by polycondensation of Si(OEt)4 and (MeO)3Si(CH2)I. The polysiloxane diamine ligand system exhibits high potential for preconcentration of divalent metal ions (Cu2+, Zn2+, and Cd2+). The tendency to chemisorb these divalent metal ions by the diamine ligand system at the optimum conditions was found in the order: Cu2+ > Zn2+ > Cd2+. Diamine ligand system suffers from leaching of ligand containing groups upon treatment with acidic solutions.