Design, synthesis, and application of chelating polymers for separation
and determination of trace and toxic metal ions. A green analytical
method*
Rakesh K. Sharma
Department of Chemistry, University of Delhi, Delhi
110 007, India
Abstract: A green analytical method was developed for separation
and preconcentration of trace amounts of copper from aqueous samples
using aurin tricarboxylic acid-immobilized silica gel (ATA-SG). This
was done by determining chemical speciation and stability constant of
Cu-ATA complex. The pH-metric studies indicate strong complexation of
Cu with ATA (log bCu2ATA = 19.56). Species distribution curve
for Cu-ATA complex indicates almost 100% complexation of copper, with
ATA forming Cu2ATA as the predominant species. Considering
the selectivity and strong interaction of ATA toward copper, ATA was
immobilized on the polymeric matrix of silica gel, and the conditions
were optimized for the uptake of copper from the aqueous solutions.
The uptake of Cu ions by ATA-SG was studied both by batch and column
methods. The method was developed for the estimation of trace amounts
of copper in various samples. Molecular modeling studies were also performed
on ATA-immobilized silica gel for gaining an insight into the active
structure of ATA on the silica surface.
* Lectures presented at the International Symposium
on Green Chemistry, Delhi, India, 10-13 January 2001. Other presentations
are published in this issue, pp. 77-203.
