Uptake of divalent metal ions (Cu2+, Ni2+, and Co2+) by polysiloxane immobilized triamine-thiol and thiolacetate ligand system

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)(2)NH-(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.