Exploring the Reduction Mechanism of ⁹⁹Tc(VII) in NaClO₄: A Spectro-Electrochimical Approach
Exploring the Reduction Mechanism of ⁹⁹Tc(VII) in NaClO₄: A Spectro-Electrochimical Approach
Rodriguez Hernandez, D. M.; Mayordomo, N.; Parra-Puerto, A.; Schild, D.; Brendler, V.; Stumpf, T.; Müller, K.
Technetium (Tc) is an environmentally relevant radioactive contaminant whose migration is limited when Tc(VII) is reduced to Tc(IV). However, its reaction mechanisms are not well understood yet. We have combined electrochemistry, spectroscopy, and microscopy (cyclic voltammetry, rotating disk electrode, X-ray photoelectron spectroscopy, and Raman and scanning electron microscopy) to study Tc(VII) reduction in non-complexing media: 0.5 mM KTcO₄ in 2 M NaClO₄ in the pH from 2.0 to 10.0. At pH 2.0, Tc(VII) first gains 2.3 ± 0.3 electrons, following Tc(V) rapidly receives 1.3 ± 0.3 electrons yielding Tc(IV). At pH 4.0−10.0, Tc(IV) is directly obtained by transfer of 3.2 ± 0.3 electrons. The reduction of Tc(VII) produced always a black solid identified as Tc(IV) by Raman and XPS. Our results
narrow a significant gap in the fundamental knowledge of Tc aqueous chemistry and are important to understand Tc speciation.
They provide basic steps on the way from non-complexing to complex media.
Keywords: Technetium; Raman spectroscopy; X-ray photoelectron spectroscopy; Non-complexing media
-
Inorganic Chemistry 61(2022)26, 10159-10166
Online First (2022) DOI: 10.1021/acs.inorgchem.2c01278
Cited 1 times in Scopus
Downloads
- Final Draft PDF 613 kB Secondary publication
Permalink: https://www.hzdr.de/publications/Publ-34883