Biosorption of copper by dried plant leaves studied by electron paramagnetic resonance and infrared spectroscopy

We report on the biosorption of copper ions by dried leaves from the Brazil ian flora. By Electron Paramagnetic Resonance (EPR), it is shown that the c opper ions are incorporated in the leaves in a strongly axial site. Washing with a basic solution does not remove the copper from the leaves, however, it modifies the axial site symmetry. Infrared absorption seems to be compa tible with a site that is located near to a simple or a double carbon-oxyge n bond. Dried leaves are a good and commercially interesting alternative fo r sorption of metal ions compared to other biomasses. (C) 2001 Elsevier Sci ence B.V. All rights reserved.