J. Iran. Chem. Soc., Vol. 6, No. 4 December 2009, pp.823~830.

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Extraction and Preconcentration Capacity of Bifunctionalized Diamine-Thiol Polysiloxane Immobilized Ligand System Towards Some Divalent Cations

N.M. El-Ashgar

Department of Chemistry, the Islamic University of Gaza, P.O. Box 108, Palestine

Porous solid bi-organofunctionalized diamine-thiol polysiloxane immobilized ligand system of the general formula P-(CH2)3-X, (where P represents [Si-O]n siloxane network and X represents a mixture of diamine; -NH(CH)2NH2 and thiol; -SH  functional groups) has been  prepared by hydrolytic polycondensation of TEOS with a mixture of 3-mercaptopropyltrimethoxysilane and 3-(2-aminoethylimino)propyltrimethoxysilane agents. The ligand system was evaluated for extraction and preconcentartion of a series of divalent metal ions from aqueous solutions including: Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Pb2+. Both batch and dynamic methods were used to examine maximum sorption capacity. The maximum binding capacity followed the sequence; Cu2+> Pb2+ > Cd2+ > Ni2+> Zn2+ > Co2+ at pH 5.5. Measurement of variation of sorption of metal ions with temperature yielded negative values of Δ and positive values of D and Δ  indicating a spontaneous and endothermic process of  binding metal ions to the ligand system.

Keywords: Immobilized-polysiloxanes, Metal ions extraction, Thermodynamic parameters, Diamine-thiol

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