Recovery of toxic heavy metals from contaminated groundwaters

The objective of this research was to characterize biologically produced materials for the recovery of toxic heavy metals from contaminated groundwaters. Specifically, components of the cells of the organism Datura innoxia (angel's trumpet) were investigated. Several approaches to understanding the interactions involved in the binding process have been employed. These methods range from the phenomenological to the fundamental. Measurement of the binding capacity of cadmium ions onto both the free Datura innoxia cells and immobilized cells has been undertaken. Immobilization of the cell material was observed to result in a significant increase in the amount of cadmium ion bound to the material. A methodology which will provide both the binding coefficient and the binding capacity of the metal ion has been developed. This is based on adsorption isotherms. A methodology for the rapid characterization of the binding of a metal pollutant with minimal generation of waste has been investigated. This methodology utilizes peak-shape analysis of transient signals resulting from the introduction of a small volume (<0.50 mL) of the metal-containing solution. Using europium as a probe species, it has been fluorometrically determined that at least two separate types of active binding sites exist on the cell walls of Datura innoxia. Specifically, these binding sites have been determined to be sulfate functionalities (pH≤3) and single and dual carboxylate containing sites (pH≤4). (author) 4 figs., 1 tab., 4 refs