New Polysiloxane-Chemically Immobilized C,C- Bipyrazolic Receptor for Heavy Metals Adsorption

A porous polysiloxane has been chemically modified with a functional C,C-bibyrazolic ligand using the heterogeneous route. This synthetic route involved the reaction of 3-glycidoxypropyltrimethoxysilane silylant agent, previously anchored on a silica surface, with C,C-bipyrazolic ligand. The new modified polysiloxane (SiL) has been characterized by elemental analysis and infrared spectra and was studied and evaluated by determination of the surface area using the BET equation, the adsorption and desorption capability using the isotherm of nitrogen and B.J.H. Pore sizes. The new inorganic-organic polymer exhibits good thermal stability determined by thermogravimetry curves and good chemical stability examined in various acidic and buffer solutions. The solid was utilized in batch method for separation and trace extraction of (Hg2+, Cd2+, Pb2+, and Cu2+) and compared with the results of classical liquid-liquid extraction with the unbound C,C-bipyrazole compound. The grafting at the surface of silica does not affect complexing properties of the ligand and the material exhibits a high selectivity toward Hg(II). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011