Supercritical Fluid Extraction of Actinides and Heavy Metals for Environmental Cleanup: A Process Development Perspective

The extraction of heavy metal ions and actinide ions is demonstrated using supercritical carbon dioxide (CO2) containing dissolved protonated ligands, such as diketones and organophosphinic acids. High efficiency extraction is observed. The mechanism of the extraction reaction is discussed and, in particular, the effect of addition of water to the sample matrix is highlighted. In-process dissociation of metal-ligand complexes for ligand regeneration and recycle is also discussed. A general concept for a process using this technology is outlined.