REMOVAL OF LANTHANUM, URANIUM AND THORIUM FROM THE CITRATE COMPLEXES BY IMMOBILIZED CELLS OF CITROBACTER SP IN A FLOW-THROUGH REACTOR - IMPLICATIONS FOR THE DECONTAMINATION OF SOLUTIONS CONTAINING PLUTONIUM

A Citrobacter sp., documented for heavy metal uptake, removed La and U from a flow presented to polyacrylamide gel-immobilized cells but rem oved little Th under the same conditions when presented alone or in co mbination with La and U. The poor removal of Th was attributable to th e strength of the complex of tetravalent actinide species with citrate cc-presented as a model chelating ligand. The implications of this fo r the treatment of wastes containing Pu(IV) are discussed.