Synthesis of an Organic Chelate Doped Sol Gel Filter to Remove Cu(II) Ions from Aqueous Solutions
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Keywords

solid-phase extraction; sol-gel; ligand; complex; absorption; emission; 1-5-methyl-4-(2-thiazolylazo)resorcinol; copper(II).

How to Cite

Zaitoun, M. (2014). Synthesis of an Organic Chelate Doped Sol Gel Filter to Remove Cu(II) Ions from Aqueous Solutions. Jordan Journal of Chemistry (JJC), 9(2), 81-96. Retrieved from http://jjc.yu.edu.jo/index.php/jjc/article/view/152

Abstract

A leaching free sol-gel glass resin was synthesized by doping 1-5-methyl-4-(2 -thiazolylazo)resorcinol (5-Me-TAR) ligand in an inert, optically transparent and porous sol-gel
glass, the produced gel matrix was used in the solid phase extraction to remove Cu(II) from
water samples. The doped ligand is dissolved in the liquid phase at the beginning of the
preparation; by hydrolysis and condensation of the alkoxysilanes, a solid glass forms around the
dopant. The ligand molecule is entrapped inside the glass pores while small Cu(II) metal ions
can diffuse into the pores where they are complexed by the ligand and retained inside the pores.
Absorption and fluorescence spectroscopy were used to characterize 5-Me-TAR ligand and 5-Me-TAR-Cu complex both in solution and sol-gel glass. The sol-gel glass precursors were
carefully selected to produce a glass composite material doped with the ligand with no leaching
especially when the glass is soaked in solution. To study complexation/adsorption, the batch
method was employed in which a known weight of the sorbent resin (glass containing the ligand)
is mixed with a known concentration of Cu(II) ions. In order to attain the maximum metal ion
complexation/adsorption capacity, these organically modified silica filters were optimized to the
optimum separation/preconcentration conditions of analytes, including the kinetics, isotherm,
effect of pH and shaking time; afterwards, the solution was filtered. The amount of copper metal
ion complexed/adsorbed was determined by the difference between the initial concentration in
aqueous solution and that found in the supernatant using a flame AA. With a loading of 0.013 g
ligand per g of dry silica (0.055 mmol ligand per g), the sol-gel silica sorbent has a capacity of
0.053 mmol Cu/g. In all cases, applications to reference materials and to real environmental
samples were investigated.

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