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Indian Journal of Chemical Technology, Vol.20, No.6, 423-428, 2013
Solid-phase extraction of Hg(II), Zn(II) and Cd(II) from water using silica gel modified with bipyrazolic tripodal receptor
An attempt has been made, to study the reaction of polar organic molecule N-(hydroxymethyl)-3,5-dimethylpyrazole with a 3-aminopropyl trimethoxysilane silylant agent, previously anchored on a silica surface in a heterogeneous way, to yield the product N,N-bipyrazole-substituted silica (Si-NP2). The product has been characterized through elemental analysis, FTIR, C-13 NMR of the solid state, nitrogen adsorption-desorption isotherm, BET surface area, BJH pore sizes, thermogravimetry curves and scanning electron microscope. The binding and extraction abilities of Si-NP2 have been investigated for Hg(II), Zn(II) and Cd(II) by batch method and the effect of pH and stirring time is studied. The optimum pH values for the quantitative extraction of these metal ions are found to be 6.0-7.5, and at these pH values, the functionalized silica further improves and shows higher affinity; the sorption capacity is in range of 486-1472 mu mol g(-1) of chelating matrix. The extracted amounts are determined by atomic absorption measurements.
Keywords:Bipyrazolic tripodal receptor;Chemically modified SiO2;Solid-phase extraction;Hg(II);Zn(II);Cd(II)