Details
| Original language | English |
|---|---|
| Pages (from-to) | 1-10 |
| Number of pages | 10 |
| Journal | Applied Clay Science |
| Volume | 176 |
| Early online date | 19 Apr 2019 |
| Publication status | Published - Aug 2019 |
Abstract
The present study investigates possible use of Layered Double Hydroxides (LDH) for Tc(VII) remediation. Mg/Al– and Mg/Fe–LDH were obtained by a hydrothermal route and thermally activated at 450 °C, which was shown to significantly improve the Tc(VII) removal efficiency. Based on XRD investigation of Tc–LDH phases, the uptake Tc(VII) from the solution follows the restoring of a LDH structure. X-ray absorption spectroscopy demonstrates that Tc ions interact solely via the Tc[sbnd]O bond, leaving no evidences of farther atomic interactions with, e.g., layers of LDH. The presence of competing anions, like NO3 −, or CO3 2– in the solution decreases Tc(VII) uptake by LDH. Maximum uptake capacity of thermally activated Mg0.67/Al0.33-LDH and Mg0.75/Fe0.25–LDH were derived from fitting the experimental data into the modified Langmuir equation and correspondingly comprise 0.227 mol/kg and 0.213 mol/kg. In agreement with these findings, theoretical simulations predicted incorporation energies for Mg0.67/Al0.33–LDH and Mg0.75/Fe0.25–LDH of −128 kJ/mol and − 110 kJ/mol, respectively. Investigation of stability of Tc–LDH in different aqueous solutions demonstrated a rather low release Tc(VII) in contact with diluted solutions containing Cl− and OH−, however, in a high saline solution, like Q-brine a rather fast release of TcO4 − occurs due to anion exchange with Cl−.
Keywords
- Disposal, Layered double hydroxides, Technetium, Uptake
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geology
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: Applied Clay Science, Vol. 176, 08.2019, p. 1-10.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Application of layered double hydroxides for 99Tc remediation
AU - Daniels, Natalia
AU - Franzen, C.
AU - Murphy, G. L.
AU - Kvashnina, K.
AU - Petrov, Valeriy
AU - Torapava, Natallia
AU - Bukaemskiy, A.
AU - Kowalski, Pawel
AU - Si, H.
AU - Ji, Y.
AU - Hölzer, Alex
AU - Walther, Clemens
N1 - Funding information: The research leading to these results received funding from the Federal Ministry of Education and Research (BMBF) under project agreement no. 02NUK021G , the Conditioning project. We also gratefully thank Dr. Victor Vinograd for scientific support in the interpretation of powder XRD results.
PY - 2019/8
Y1 - 2019/8
N2 - The present study investigates possible use of Layered Double Hydroxides (LDH) for Tc(VII) remediation. Mg/Al– and Mg/Fe–LDH were obtained by a hydrothermal route and thermally activated at 450 °C, which was shown to significantly improve the Tc(VII) removal efficiency. Based on XRD investigation of Tc–LDH phases, the uptake Tc(VII) from the solution follows the restoring of a LDH structure. X-ray absorption spectroscopy demonstrates that Tc ions interact solely via the Tc[sbnd]O bond, leaving no evidences of farther atomic interactions with, e.g., layers of LDH. The presence of competing anions, like NO3 −, or CO3 2– in the solution decreases Tc(VII) uptake by LDH. Maximum uptake capacity of thermally activated Mg0.67/Al0.33-LDH and Mg0.75/Fe0.25–LDH were derived from fitting the experimental data into the modified Langmuir equation and correspondingly comprise 0.227 mol/kg and 0.213 mol/kg. In agreement with these findings, theoretical simulations predicted incorporation energies for Mg0.67/Al0.33–LDH and Mg0.75/Fe0.25–LDH of −128 kJ/mol and − 110 kJ/mol, respectively. Investigation of stability of Tc–LDH in different aqueous solutions demonstrated a rather low release Tc(VII) in contact with diluted solutions containing Cl− and OH−, however, in a high saline solution, like Q-brine a rather fast release of TcO4 − occurs due to anion exchange with Cl−.
AB - The present study investigates possible use of Layered Double Hydroxides (LDH) for Tc(VII) remediation. Mg/Al– and Mg/Fe–LDH were obtained by a hydrothermal route and thermally activated at 450 °C, which was shown to significantly improve the Tc(VII) removal efficiency. Based on XRD investigation of Tc–LDH phases, the uptake Tc(VII) from the solution follows the restoring of a LDH structure. X-ray absorption spectroscopy demonstrates that Tc ions interact solely via the Tc[sbnd]O bond, leaving no evidences of farther atomic interactions with, e.g., layers of LDH. The presence of competing anions, like NO3 −, or CO3 2– in the solution decreases Tc(VII) uptake by LDH. Maximum uptake capacity of thermally activated Mg0.67/Al0.33-LDH and Mg0.75/Fe0.25–LDH were derived from fitting the experimental data into the modified Langmuir equation and correspondingly comprise 0.227 mol/kg and 0.213 mol/kg. In agreement with these findings, theoretical simulations predicted incorporation energies for Mg0.67/Al0.33–LDH and Mg0.75/Fe0.25–LDH of −128 kJ/mol and − 110 kJ/mol, respectively. Investigation of stability of Tc–LDH in different aqueous solutions demonstrated a rather low release Tc(VII) in contact with diluted solutions containing Cl− and OH−, however, in a high saline solution, like Q-brine a rather fast release of TcO4 − occurs due to anion exchange with Cl−.
KW - Disposal
KW - Layered double hydroxides
KW - Technetium
KW - Uptake
UR - http://www.scopus.com/inward/record.url?scp=85064426577&partnerID=8YFLogxK
U2 - 10.1016/j.clay.2019.04.006
DO - 10.1016/j.clay.2019.04.006
M3 - Article
AN - SCOPUS:85064426577
VL - 176
SP - 1
EP - 10
JO - Applied Clay Science
JF - Applied Clay Science
SN - 0169-1317
ER -