Abstract/Description/Artist Statement

Pertechnetate (TcO₄⁻) is a persistent radioactive byproduct resulting from the decay of uranium-235 or plutonium-239 in the nuclear fuel cycle. Its high environmental mobility, long half-life, and significant beta radiation make TcO₄⁻ a critical contaminant. Structurally tetrahedral and water-soluble, TcO₄⁻ behaves similarly to the sulfate anion, facilitating its rapid introduction into ecosystems.

It bioaccumulates in lower-level organisms, propagating radioactive and toxic effects through food chains. In mammals, technetium-99 accumulates in the thyroid and may also impact fetal development. Its small charge, chemical stability, and solubility present significant challenges for effective remediation.

Current remediation methods often suffer from poor selectivity, dependence on impractical reaction conditions, or the use of environmentally harmful solvents and polymers. The perrhenate (ReO₄⁻) anion is a non-radioactive analogue of TcO₄⁻, which is commonly used as an analogue in remediation studies. A promising approach involves using photosensitisers to create a redox-active environment, enabling the reduction and immobilization of perrhenate.

Tris(2,2’-bipyridine)ruthenium(II) chloride is a well-known photosensitiser, which has the strongest absorption peak in the blue light region, around 450-460 nm. This photosensitiser is capable of generating reactive oxygen species under light irradiation. This research project will utilize tris(2,2’-bipyridine)ruthenium(II) chloride under photocatalytic conditions during its reaction with ReO₄⁻. As such, it is hypothesized that tris(2,2’-bipyridine)ruthenium(II) chloride will selectively and efficiently reduce ReO₄⁻ to insoluble ReO₂ under aerobic conditions.

It is expected that this technique will offer enhanced selectivity and effectiveness, even in the presence of competing ions, while presenting a viable pathway for the remediation of pertechnetate contamination.

Presenting Author Name/s

Kaylin L. Thomas

Faculty Advisor/Mentor

Alvin A. Holder

Faculty Advisor/Mentor Email

aholder@odu.edu

Faculty Advisor/Mentor Department

Chemistry and Biochemistry

College/School Affiliation

College of Sciences

Student Level Group

Undergraduate

Presentation Type

Poster

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Remediation of ammonium perrhenate via tris(2,2’-bipyridine)ruthenium(II) chloride

Pertechnetate (TcO₄⁻) is a persistent radioactive byproduct resulting from the decay of uranium-235 or plutonium-239 in the nuclear fuel cycle. Its high environmental mobility, long half-life, and significant beta radiation make TcO₄⁻ a critical contaminant. Structurally tetrahedral and water-soluble, TcO₄⁻ behaves similarly to the sulfate anion, facilitating its rapid introduction into ecosystems.

It bioaccumulates in lower-level organisms, propagating radioactive and toxic effects through food chains. In mammals, technetium-99 accumulates in the thyroid and may also impact fetal development. Its small charge, chemical stability, and solubility present significant challenges for effective remediation.

Current remediation methods often suffer from poor selectivity, dependence on impractical reaction conditions, or the use of environmentally harmful solvents and polymers. The perrhenate (ReO₄⁻) anion is a non-radioactive analogue of TcO₄⁻, which is commonly used as an analogue in remediation studies. A promising approach involves using photosensitisers to create a redox-active environment, enabling the reduction and immobilization of perrhenate.

Tris(2,2’-bipyridine)ruthenium(II) chloride is a well-known photosensitiser, which has the strongest absorption peak in the blue light region, around 450-460 nm. This photosensitiser is capable of generating reactive oxygen species under light irradiation. This research project will utilize tris(2,2’-bipyridine)ruthenium(II) chloride under photocatalytic conditions during its reaction with ReO₄⁻. As such, it is hypothesized that tris(2,2’-bipyridine)ruthenium(II) chloride will selectively and efficiently reduce ReO₄⁻ to insoluble ReO₂ under aerobic conditions.

It is expected that this technique will offer enhanced selectivity and effectiveness, even in the presence of competing ions, while presenting a viable pathway for the remediation of pertechnetate contamination.