INVESTIGATION OF UO22+ BINDING-SITES ON DATURA-INNOXIA USING UO22+ LUMINESCENCE

A pulsed tunable dye laser has been used to obtain the emission spectra and fluorescence decay curves of solid UO22+-Datura innoxia and a series of UO22+-containing complexes at liquid nitrogen temperature. The decay curves of UO22+-Datura exhibited a bi-exponential decay, suggesting that at least two different binding sites are present on the walls of nonliving D. innoxia cells. The model solutions containing carboxyl, amine, hydroxyl, phosphoryl, sulfate, and sulfonate functionalities have been utilized to identify the functionalities involving in the binding of UO22+ to nonliving D. innoxia cell walls. Phosphoryl and dicarboxyl groups have been demonstrated to be the dominant functional groups responsible for the binding of uranyl ions on D. innoxia cell walls.