Biosorption of copper ions by dried leaves: chemical bonds and site symmetry

The biosorption of copper by dried leaves was studied by Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance (EPR). From FTIR measurements, we conclude that the presence of copper ions in the biomass affects the bands corresponding to C=C vibrations of carbon rings of the biomass. In the EPR spectra, the Cu2+ ion is seen to be incorporated into the biomass in a site with an axial symmetry. We propose a model for the sorption site where the copper ions are located between two adjacent carbon rings in an interstitial site in the fibers of the biomass. (C) 2003 Elsevier B.V. All rights reserved.