Technetium(IV) oxide colloids produced by radiolytic reactions in aqueous pertechnetate solution

Sekine, Tsutomu; Narushima, H.; Suzuki, Tomo; Takayama, T.; Kawamura, Hiroshi; Lin, Mingzhang; Katsumura, Yosuke

doi:10.1016/j.colsurfa.2004.08.074

Cited by 16 publications

(13 citation statements)

References 12 publications

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“…The UV/Visible spectra for all 3 concentrations show a peak at 490 nm that is attributed to the reduced Tc IV d‐d transition shown in Figure S7. This absorbance is similar to one absorbed for Tc reduced by gamma irradiation in sulfuric acid , , …”

Section: Resultssupporting

confidence: 62%

“…One such species has been examined by X‐ray Absorption Spectroscopy (XANES and EXAFS) to demonstrate the Tc IV oxidation state and suggest a Tc 3 O 4 4+ polymeric species at low pH . It has also been suggested that the polymeric Tc IV species would aggregate at higher pH resulting in TcO 2 · n H 2 O as characterized by Transmission Electron Microscopy (TEM) . The amounts of polymeric Tc IV species increased with increasing dose and 80 % of TcO 4 – was converted to polymeric Tc IV species at 6.5 kGy.…”

Section: Resultsmentioning

confidence: 99%

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Strategies for the Photoreduction of Tc‐99 Pertechnetate to Low‐Valent Tc by Keggin Polyoxometalates

et al. 2020

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Technetium‐99 (half‐life of 2.1 × 105 yrs, βmax = 0.29 MeV) is a hazardous radiological contaminant, which, in its predominant form of pertechnetate (TcO4–), is highly mobile in the environment. Most strategies for the removal of pertechnetate from the environment involve uptake and/or absorption of pertechnetate using resins, clays, cationic metal‐organic frameworks and even thorium borate ceramic like materials. Alternative approaches have involved the reduction and subsequent sequestration of lower valent technetium species using iron, sulfides, or iron sulfides. Our lab has explored this strategy using the lacunary alpha‐2 Wells–Dawson polyoxometalate (α2‐[P2W17O61]10–) to both reduce and sequester lower valent technetium, and we have reported on the ligand features that stabilize the reduced species. In this work we investigate the potential of “plenary” Keggin POMs (XW12O40n–) (X = P, Si, Al, n = 3, 4, 5, respectively) to both reduce TcO4– and stabilize the reduced Tc species. Specifically, we report on the mechanism by which the reduction of technetium occurs and find that PW12, SiW12, and AlW12 promote the reduction of TcO4– to lower valent states. X‐ray absorption spectroscopy was used to confirm a combination of TcIV {in the form of TcO2·2H2O and Tc2(µ‐O)24+} and TcV, which is subsequently complexed into a POM defect as a TcV=O species.

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Section: Resultssupporting

confidence: 62%

Section: Resultsmentioning

confidence: 99%

Strategies for the Photoreduction of Tc‐99 Pertechnetate to Low‐Valent Tc by Keggin Polyoxometalates

et al. 2020

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“…In experiments with high concentrations of technetium (greater than10 -5 M Tc), several investigators have reported formation of colloids of technetium at moderately acidic (pH ≤4) Sekine et al 2004;Vichot et al 2002) and under reducing conditions (Sekine et al 2002). They report brown to brownish-black turgid solutions that are consistent with the presence of colloids.…”

Section: Colloidsmentioning

confidence: 48%

“…In the latter case, technetium in octahedral coordination connects to other octahedrons through double bridging between two ligands (i.e., edge-sharing polyhedra), rather than by direct metal-metal bonding. Sekine et al (2002Sekine et al ( , 2004) also showed that colloids of technetium will form from pertechnetate solutions exposed to radiolysis at acid to near-neutral pH values. Radiolysis caused reduction of Tc(VII) and formation of Tc(IV) polymers and colloids, first as Tc(IV), then as TcO 2 ·nH 2 O nanoparticles as the solution pH increased.…”

Section: Colloidsmentioning

confidence: 99%

The Geochemistry of Technetium: A Summary of the Behavior of an Artificial Element in the Natural Environment

Icenhower¹,

Qafoku²,

Martin³

et al. 2008

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“…Technetium oxide colloids (TcO 2 n·H 2 O) [13] were formed by bremsstrahlung irradiation of aqueous solutions of pertechnetate (TcO 4 -). A transmission electron microscopy (TEM) analysis showed that the size of colloids was distributed around 30 to 130 nm in diameter.…”

Section: Formation Of Tc(iv) Oxide Colloids By Bremsstrahlung Irradiamentioning

confidence: 99%

Status of the electron accelerator for radioanalytical studies at Tohoku University

et al. 2006

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We introduce the status of the 300 MeV electron linear accelerator used for radioanalytical studies at Tohoku University. In the accelerator facility, several scientific programs for producing radioactivity have been performed in several fields, such as photon-activation analysis, nuclear chemistry, hot-atom chemistry, and radioactive tracers for material science. First, we introduce an outline of the facility and the irradiation system for producing radioactivity. Then, several topics in these fields are explored in detail.

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Technetium(IV) oxide colloids produced by radiolytic reactions in aqueous pertechnetate solution

Cited by 16 publications

References 12 publications

Strategies for the Photoreduction of Tc‐99 Pertechnetate to Low‐Valent Tc by Keggin Polyoxometalates

Strategies for the Photoreduction of Tc‐99 Pertechnetate to Low‐Valent Tc by Keggin Polyoxometalates

The Geochemistry of Technetium: A Summary of the Behavior of an Artificial Element in the Natural Environment

Status of the electron accelerator for radioanalytical studies at Tohoku University

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