Pertechnetate (TcO4-) sequestration from groundwater by cost-effective organoclays and granular activated carbon under oxic environmental conditions
Technetium-99 (Tc-99) is a major risk driver at nuclear power plants and several US Department of Energy (DOE) sites. Pertechnetate (TcO4-), the most common chemical form present in liquid nuclear waste and the environment, displays limited adsorption onto sediments, making it highly mobile and difficult to immobilize. In this work, inexpensive organoclays and granular activated carbon (GAC) were investigated for TcO(4)(- )sequestration from artificial groundwater (AGW). The Tc adsorption capacities were 15 mg/g for organoclays and 25 mg/g for GAC from pH 3-12 AGW under oxic conditions. Competitive NO3- at two orders of magnitude greater concentration than TcO4- reduced the Tc adsorption capacity by only 9-25%. In addition, the adsorbed Tc was effectively desorbed by KI, but not Na2SO4, and the regenerated sorbents retained their Tc removal capacity. X-ray absorption spectroscopy demonstrated that the Tc species bound to the organoclays and GAC was Tc(VII) (i.e., TcO4-), rather than Tc(IV). Thus, the inexpensive organoclays and GAC are highly effective at sequestering Tc-99 in its naturally existing TcO4- without requiring costly reductive systems, which may provide a practical solution for removing (TcO4-)-Tc-99 from environmental systems.
- Research Organization:
- Savannah River Site (SRS), Aiken, SC (United States); Univ. of Georgia, Aiken, SC (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM); USDOE Office of Science (SC), Biological and Environmental Research (BER); SRNL Laboratory Directed Research and Development (LDRD) Program
- Grant/Contract Number:
- AC09-08SR22470; FC09-07SR22506; AC02-06CH11357; LDRD-2014-00028; LDRD-2015-00014
- OSTI ID:
- 1512416
- Alternate ID(s):
- OSTI ID: 1510257; OSTI ID: 1637059
- Report Number(s):
- SRNL-STI-2018-00137
- Journal Information:
- Chemical Engineering Journal, Vol. 360; ISSN 1385-8947
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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