UPTAKE OF DIVALENT METAL IONS (CU2+, NI2+, AND CO2+) BY POLYSILOXANE IMMOBILIZED TRIAMINE-THIOL AND THIOL-ACETATE LIGAND SYSTEM

Abstract

Insoluble porous solid polysiloxanes-immobilized ligand systems bearing hybrid mixture of triamine-thiol ligand and thiol-acetate ligand as chelating functional groups of the general formula P-(CH₂)₃-X(Y) (Where P represents a silica like siloxane framework and X represents a mixture of triamine and thiol, -NHCH₂)₂NH-(CH₂)₂-NH₂ and –SH, and Y represents a thiol-acetate -SCH₂COOH functional groups) has been prepared. The immobilized triamine-thiol ligand system was prepared through the sol-gel process by hydrolytic polycondensation of Si(OEt)₄ and a mixture of 3-mercaptopropyltrimethoxysilane and 3-diethylenetriaminepropyltrimethoxysilane coupling agents. The immobilized thiol-acetate ligand system was prepared by the reaction of polysiloxane immobilized thiol ligand with ethylchloroacetate. These ligand systems exhibit high potential for extraction and preconcentration of divalent metal ions (Co²⁺, Ni²⁺ and Cu²⁺). The results indicate that the triamine-thiol ligand seems to form 1:1 metal to ligand complexes, where there is no clear stoichiometry structure in the case of the thiol-acetate ligand.