1. FORBES RESEARCH GROUP Tori Forbes W374 tori-forbes@uiowa.edu

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

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 10 10 gal  Contaminated Soil and Sediment = 75 million m 3  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 Sludge 5 M NaOH, pH14 Boehmite (AlOOH) And An(OH) x solid + Soluble Al(OH) 3 Vitrified into glass waste Nitric acid Soluble An and Al 3+ species ? 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. [Th 2 Al 6 (OH) 14 (H 2 O) 12 (HEDTA) 2 ](NO 3 ) 6 (H 2 O) 12 Monoclinic, P2 1 /c a = 11.198 Å b = 13.210 Å c = 23.115 Å α = 90° β = 96.375° γ = 90° R 1 = 0.0316, R wp =0.0851 GOF = 1.10 Fairley, Unruh, Abeysinghe, and Forbes, In preparation

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

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

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

12. Are molecular clusters the building blocks? 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). Al 26 Al 30 Al 32 ε-Al 13 δ-Al 13

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… Abeysinghe and Forbes, In preparation [(Zn(NTPA)(H 2 O)) 2 Al 2 (NPTA) 2 Al 30 O 8 (OH) 62 (H 2 o) 2o ](2-6NDS) 5 [(Cu(H 2 O) 2 ) 2 Al 30 O 8 (OH) 60 (H 2 o) 22 ](2-6NDS) 9

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