Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8083019 | Journal of Environmental Radioactivity | 2014 | 8 Pages |
Abstract
Technetium-99 (99Tc), iodine-129 (129I), and cesium-137 (137Cs) are among the key risk-drivers for environmental cleanup. Immobilizing these radionuclides, especially TcO4â and Iâ, has been challenging. TcO4â and Iâ bind very weakly to most sediments, such that distribution coefficients (Kd values; radionuclide concentration ratio of solids to liquids) are typically <2 mL/g; while Cs sorbs somewhat more strongly (Kd â¼Â 50 mL/g). The objective of this laboratory study was to evaluate 13 cost-effective sorbents for TcO4â, Iâ, and Cs+ uptake from contaminated groundwater and sediments. Two organoclays sorbed large amounts of TcO4â (Kd > 1 Ã 105 mL/g), Iâ (Kd â¥Â 1 Ã 104 mL/g), and Cs+ (Kd > 1 Ã 103 mL/g) and also demonstrated a largely irreversible binding of the radionuclides. Activated carbon GAC 830 was effective at sorbing TcO4â (Kd > 1 Ã 105 mL/g) and Iâ (Kd = 6.9 Ã 103 mL/g), while a surfactant modified chabazite was effective at sorbing TcO4â (Kd > 2.5 Ã 104 mL/g) and Cs+ (Kd > 6.5 Ã 103 mL/g). Several sorbents were effective for only one radionuclide, e.g., modified zeolite Y had TcO4âKd > 2.3 Ã 105 mL/g, AgS had Iâ Kd = 2.5 Ã 104 mL/g, and illite, chabazite, surfactant modified clinoptilolite, and thiol-SAMMS had Cs+Kd > 103 mL/g. These low-cost and high capacity sorbents may provide a sustainable solution for environmental remediation.
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Authors
Dien Li, Daniel I. Kaplan, Anna S. Knox, Kimberly P. Crapse, David P. Diprete,