title: Ion pairing as a strategy for extraction by modified supercritical carbon dioxide: extraction of radioactive metal ions.
abstract: Supercritical fluid carbon dioxide was investigated for its potential to extract perrhenate ion pairs. This has implications for radioactive waste processing because Tc-99, the second row congener of Re, is produced in approximately 6% fission yield from nuclear fuel and pertechnetate is its most common chemical form in aqueous environments. The variables examined to maximize extraction of the perrhenate ion pair were temperature, pressure, solvent modification, and ion-pairing agents. The tetrabutyl-ammonium cation was found to form the most efficient ion pair for extracting perrhenate using methanol-modified (approximately 10%) SFCO2 at 70 degrees C and 477 atm, with 0.083 mg of Re/g of SFCO2 extracted.
authors.affiliation: Department of Chemistry, University of Missouri-Columbia, 65201, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Gawenis
authors.forename: J F
authors.initials: JF
authors.lastname: Kauffman
authors.forename: S S
authors.initials: SS
authors.lastname: Jurisson