posted on 2013-07-02, 00:00authored byBrian J. Riley, Jaehun Chun, Wooyong Um, William C. Lepry, Josef Matyas, Matthew J. Olszta, Xiaohong Li, Kyriaki Polychronopoulou, Mercouri G. Kanatzidis
The
efficient capture of radionuclides with long half-lives such as technetium-99
(99Tc), uranium-238 (238U), and iodine-129 (129I) is pivotal to prevent their transport into groundwater
and/or release into the atmosphere. While different sorbents have
been considered for capturing each of them, in the current work, nanostructured
chalcogen-based aerogels called chalcogels are shown to be very effective
at capturing ionic forms of 99Tc and 238U, as
well as nonradioactive gaseous iodine (i.e., a surrogate for 129I2), irrespective of the sorbent polarity. The
chalcogel chemistries studied were Co0.7Bi0.3MoS4, Co0.7Cr0.3MoS4,
Co0.5Ni0.5MoS4, PtGe2S5, and Sn2S3. The PtGe2S5 sorbent performed the best overall with capture efficiencies
of 98.0% and 99.4% for 99Tc and 238U, respectively,
and >99.0% for I2(g) over the duration of the experiment.
The capture efficiencies for 99Tc and 238U varied
between the different sorbents, ranging from 57.3–98.0% and
68.1–99.4%, respectively. All chalcogels showed >99.0% capture
efficiency for iodine over the test duration. This versatile nature
of chalcogels can provide an attractive option for the environmental
remediation of the radionuclides associated with legacy wastes from
nuclear weapons production as well as wastes generated during nuclear
power production or nuclear fuel reprocessing.