The extraction of strontium and cesium ions from high ionic strength acid, base, and salt solutions into an organic extractant
consisting of alkyl cobalt dicarbollide and polyethylene glycol (PEG) in diethylbenzene was investigated. Adding hexaethylene
glycol or PEG-400 improved the strontium extraction ≥100-fold, while cesium extraction was decreased at high PEG concentrations.
The extractions are rapid and selective, even in the presence of molar concentrations of sodium ion, suggesting that alkyl
cobalt dicarbollide extractants are useful for the treatment of alkaline nuclear wastes. A method for the synthesis of tetra-n-hexyl(cobalt dicarbollide) is described.
Authors:D. E. Berning, N. C. Schroeder and R. M. Chamberlin
The autoreduction of pertechnetate (99TcO4-) to Tc(IV/V) alkoxide complexes in aqueous, alkaline, solutions is described. Solutions of sodium pertechnetate (0.01M) reacted with nitrogen and oxygen donor ligands (1.0M) in 2M sodium hydroxide. Solutions containing nitrogen donor ligands (e.g., EDTA) showed the initial formation of lightly colored complexes followed by rapid decomposition in air. In contrast, stable, reduced complexes were formed within minutes of mixing pertechnetate with mono- and disaccharides in strong base, as indicated by a persistent color change. Chemical yields of these reactions were determined by thin layer chromatography or paper chromatography and radiochemically assayed with a Bioscan imaging scanner. Analysis by UV-vis spectroscopy suggested that Tc(IV) or Tc(V) complexes were produced, with the oxidation state dependent on the reducing ligand. These experiments may help explain the reduction of pertechnetate to the soluble complexes that have been found in the Hanford nuclear waste tanks.
Authors:S. Wagner, S. Boone, J. Chamberlin, C. Duffy, D. Efurd, K. Israel, N. Koski, D. Kottmann, D. Lewis, P. Lindahl, F. Roensch and R. Steiner
Utilization of thermal ionization mass spectrometry as a routine analytical service provided to the Los Alamos National Laboratory Bioassay Program has evolved significantly since its implementation just over three years ago. Converting this unique research tool designed to support nuclear weapons testing to a quasi-production mode for the routine analysis of ~300 urine samples/year for ultra-low levels of plutonium has required resolution of numerous practical issues. These issues include clean-room sample preparation, adequate tracer recovery, customer specified turn-around times, throughput, water and urine blank values, statistical data reduction, and quality control and performance evaluation sample requirements.