Removal of Plutonium-239 and Americium-241 from rocky flats soil by leaching
Article
Lu, N, Kung, KS, Mason, CFV et al. (1998). Removal of Plutonium-239 and Americium-241 from rocky flats soil by leaching
. ENVIRONMENTAL SCIENCE & TECHNOLOGY, 32(3), 370-374. 10.1021/es970329t
Lu, N, Kung, KS, Mason, CFV et al. (1998). Removal of Plutonium-239 and Americium-241 from rocky flats soil by leaching
. ENVIRONMENTAL SCIENCE & TECHNOLOGY, 32(3), 370-374. 10.1021/es970329t
A proposed remediation technology to remove Pu and Am from Rocky Flats Plant (RFP) soil combines hot solution (80 °C) leach with complexing (e.g., citrate) and reducing (e.g., ascorbic acid or dithionite) agents. The majority of the Pu and Am in the RFP soil was associated with soil size particles of <0.50 mm. The Pu and Am in the soil with particle sizes of <0.25 mm are generally associated with the soil iron oxides, while Pu and Am in the soil particles >0.25 mm are generally associated with soil organic matter (SOM). A laboratory column-leaching process was used (1) to evaluate the leachability of 239,240Pu and 241-Am from RFP soil using aqueous solutions of sodium chloride (NaCl), sodium citrate (Cit), sodium citrate- ascorbic acid (CAA), and sodium citrate-sodium dithionite (CD) and (2) to determine the effects of temperature and solution concentration to extract 239,240Pu and 241 Am from soil. Additional batch experiments measured the influences of soil particle size, soil organic matter (SOM), and iron oxide on the solubility of α active contaminants. Our results show that the complexing-reducing reagent of citrate-ascorbic acid and citrate- dithionite removed at least 70% of α active contaminants from RFP site soil. However, the effectiveness of each leaching scheme varies with the particle size fractions. Our results also demonstrate that Pu and Am are effectively removed from RFP site soil at room temperature, and that the solution concentration of 0.1/0.1 or 0.05/0.05 is the optimum molar concentration.
