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Forbes Research Group

Forbes Research Group. Tori Forbes W374 tori-forbes@uiowa.edu. Research Focus of Forbes Group. Formation of colloids/nanoparticles through hydrolysis. Transport of Nuclear Waste in the Environment. Fundamental Structural Chemistry of Actinides. Novikov et al., Science 2008.

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Forbes Research Group

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  1. Forbes Research Group Tori Forbes W374 tori-forbes@uiowa.edu

  2. Research Focus of Forbes Group Formation of colloids/nanoparticles through hydrolysis Transport of Nuclear Waste in the Environment Fundamental Structural Chemistry of Actinides Novikov et al., Science 2008

  3. Nuclear Waste

  4. Legacy of Environmental Contamination • Over 1,000 locations in the US are contaminated with radiation. • 19 sites on National Priority List • 88 million gal waste in 230 underground tanks (some leaking) • Contaminated groundwater = 1.15 x 1010 gal • Contaminated Soil and Sediment = 75 million m3 • 5 sites account for 71% of the remediation work: Rocky Flats, CO Idaho National Laboratory, ID Savannah River, SC Oak Ridge, TN Hanford, WA

  5. Project 1: Hanford U.S. Department of Energy Lichtner et al., Comp. & Geo. 2003

  6. Separations process at Hanford ? 5 M NaOH, pH14 Boehmite (AlOOH) And An(OH)xsolid + Soluble Al(OH)3 Nitric acid Soluble An and Al3+ species Sludge Vitrified into glass waste We have no current knowledge of the chemical species that form when actinides and other metals (such as aluminum) undergo hydrolysis… Hydrolysis products cause problems in separations (fouling of chromographic columns, incomplete separations, salting out), leading to delays in remediation and huge additional expense.

  7. Synthesis and Crystal Structure Determination

  8. [Th2Al6(OH)14(H2O)12(HEDTA)2](NO3)6(H2O)12 Monoclinic, P21/c a = 11.198 Å b = 13.210 Å c = 23.115 Å α = 90° β = 96.375° γ = 90° R1 = 0.0316, Rwp =0.0851 GOF = 1.10 Fairley, Unruh, Abeysinghe, and Forbes, In preparation

  9. Project 2: The Plutonium Problem! At the source 239,240Pu = 1000 bec/L Well 41/77 (0.5 km) 239,240Pu = 4.8 bec/L Well 3/68 (2 km) 239,240Pu = 1.62 bec/L Well 14/68 (4 km) 239,240Pu = 0.3 bec/L Acceptable EPA limits for drinking water (total radioactivity) = 0.55 bec/L Novikovet al., Science, (2008)

  10. Small particles/colloids are to blame! Adsorption of actinides We can not predict the mobility of plutonium in the environment! We have no molecular understanding of small nanoparticles! Novikovet al., Science, (2008)

  11. Colloidal transport in the Environment Overall Question: What are the structural characteristics of the colloidal particles?? Precipitation of colloidal “floc” Colloidal Particles Aggregation in solution Precipitation of colloidal “floc” Colloidal Particles Aggregation in solution

  12. Are molecular clusters the building blocks? ε-Al13 δ-Al13 Al26 Al30 Al32 Johansson Acta. Chem. Scand. (1960); Roswell and Nazar., J. Am. Chem. Soci. (2000); Forbes and Abeysinghe, in preparation; Allouche et al, Angew. Che. Int. Ed (2000); Sun et al., Inorg Chem. (2011).

  13. Pair-distribution function analysis High energy X-ray scattering technique Advanced Photon Source, Argonne National Laboratory, Beamline 11-1D-B 58.26 keV, wavelength = 0.2127 Å

  14. Structure Characterization of Colloidal “Floc” Colloidal “Floc” Molecular cluster

  15. Models for contaminant transport… [(Zn(NTPA)(H2O))2Al2(NPTA)2Al30O8(OH)62(H2o)2o](2-6NDS)5 [(Cu(H2O)2)2Al30O8(OH)60(H2o)22](2-6NDS)9 Abeysinghe and Forbes, In preparation

  16. Potential Projects • Aluminum-actinide chemistry – What waste products are likely to form at the Hanford Site in Washington state? • Aluminum “floc”– pH changes, thermal restructuring • Extension to iron oxyhydroxide, manganese oxides and actinides (Th, U, Np?, Pu?) • Linking laboratory experiments to environmental systems • Developing fluorescent tags or radiotracer techniques to track nanoparticles in environmental systems • Novel materials for advanced remediation strategies

  17. Current Group members Samangi Abeysinghe Jacob Ertman Melissa Fairley Erin Flores Anna Libo Kyle Gojdas Eric Jetter Dr. Daniel Unruh

  18. Tori Forbes, W374, tori-forbes@uiowa.edu Fundamental Actinide Chemistry (Th, U, Np) Formation nanoparticles or nanominerals Transport of Nuclear Waste in the Environment Novikov et al., Science 2008

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