Speciation of technetium in acidic media : effect of α radiations
type: Dataset
description: This project is part of the fundamental study of technetium speciation in highly acidic medium. The behaviour of technetium in HTFMS was carried out in the absence then in the presence of α irradiation. Given these two different conditions, spectrophotometric results of Tc(VII) reduction are similar. XAS analysis indicates the formation of a cyclic dimer of Tc(IV) complexed to triflate ligands and formulated asTc₂O₂(CF₃SO₃)₄(H₂O)₄. This compound is linearized to TcIV-O-TcIV with the increase of HTFMS concentration. At high concentration of HTFMS +98% (11.15 M), the protonated species TcO₃(OH)(H₂O)₂ which is formed in the absence of external ionizing radiations, is reduced to the V oxidation state under α irradiation. Structural characterization by EXAFS spectroscopy and DFT calculations suggests the formation of monomer species of Tc(V)-triflate complexes where [OTc(F₃CSO₃)₂(H₂O)₂]⁺ and [OTc(F₃CSO₃)₂(OH)₂]⁻ compounds were proposed. In concentrated H₂SO₄ (CH₂SO₄ ≥ 12 M), α-radiolysis experiments of Tc(VII) were performed in order to compare the radiolytic behaviour of Tc(VII) in both comparable media HTFMS and H₂SO₄. XANES studies show that radiolytic reduction of Tc(VII) leads to the formation of Tc(V)-Tc(VII) mixture in H₂SO₄ 13 M and just Tc(V) in 18 M of H₂SO₄. The analysis of EXAFS spectra is consistent with the formation of [TcO(HSO₄)₃(H₂O)₂] and [TcO(HSO₄)₃(H2O)(OH)]⁻ monomer complexes in H₂SO₄ 13 M and [Tc(HSO₄)₃(SO₄)(H₂O)] and [Tc(HSO₄)₃(SO₄)(OH)]⁻ species at 18 M of H₂SO₄.
landing page: https://theses.hal.science/tel-00937594
identifier: NNT: 2013EMNA0114
keyword: chimanalchemical-sciencesanalytical-chemistry
keyword: chimtheochemical-sciencestheoretical-andor-physical-chemistry
keyword: dft
keyword: hso
keyword: htfms
keyword: infoeu-reposemanticsdoctoralthesis
keyword: lpha-radiolysis
keyword: radiolyse
keyword: speciation
keyword: technetium
keyword: theses
keyword: xas-xanes-and-exafs
keyword: xas-xanes-et-exafs
issued: 2026-05-07T05:31:39.139651
modified: 2026-05-07T05:31:39.139658
language: fr
contact point: Organization
  fn: CCSD

test_moissonnage_selune
type: Agent

Speciation of technetium in acidic media : effect of α radiations
type: Distribution
format: HTML
access URL: https://theses.hal.science/tel-00937594
issued: 2026-05-07T05:31:39.148175
modified: 2026-05-07T05:31:39.127526