Effect of Selective Dissolution, Electrolytes, Aeration, and Sterilization on Technetium-99 Sorption by Soils1
- Edward R. Landa,
- Lisa (Hart) Thorvig and
- Robert G. Gast2
The objective of this study was to determine the extent that technetium-99, a long-lived beta-emitting radionuclide, might be sorbed from aqueous solution by 11 well-characterized soils, and to elucidate the sorption mechanisms involved. About 98% of the added 99Tc was sorbed within a period of 2 to 5 weeks by 8 of the 11 soils. The slow kinetics observed and the removal of trace quantities of 99Tc from solution in the presence of large amounts of chloride and phosphate tend to rule out anion exchange as the sorption mechanism. The lack of sorption exhibited by the low organic matter soils, the reduction in sorption following H2O2 digestion of the soil, and the high recoveries of sorbed 99Tc on extraction with NaOH suggest a role for the living and/or nonliving organic fraction of the soil. Sterilization of previously sorbing soils eliminated the sorption ability, indicating a microbial role in the process. Results of aeration experiments were ambiguous but suggest that anaerobic conditions are not a prerequisite for 99Tc sorption by soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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