Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetry

Zhuoxi Li; Yuyu Liang; Xiang Li; Wanjun Mu; Baihua Chen; Jun Tu; Lina Lv; Yanqiu Yang; Xingliang Li

doi:10.1016/j.nucana.2023.100082

Nuclear Analysis (Sep 2023)

Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetry

Zhuoxi Li,
Yuyu Liang,
Xiang Li,
Wanjun Mu,
Baihua Chen,
Jun Tu,
Lina Lv,
Yanqiu Yang,
Xingliang Li

Affiliations

Zhuoxi Li: Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China; Graduate School of China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China
Yuyu Liang: Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China; Graduate School of China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China
Xiang Li: Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China; Graduate School of China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China
Wanjun Mu: Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China
Baihua Chen: Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China
Jun Tu: Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China; Corresponding author.
Lina Lv: Fundamental Science on Nuclear Wastes and Environment Safety Laboratory, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China
Yanqiu Yang: Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China
Xingliang Li: Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China; Corresponding author.

DOI: https://doi.org/10.1016/j.nucana.2023.100082
Journal volume & issue: Vol. 2, no. 3
p. 100082

Abstract

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The thermodynamic parameters of the complexes of Th with N-methylethylenediamine-N,Nʹ,Nʹ-triacetic acid (MEDTA; denoted as H3L with three dissociable protons) were studied. Potentiometry and microcalorimetry were used to determine formation constants and enthalpies, respectively. Thermodynamic analysis revealed two successively formed complexes, namely, ThL+ and ThL22− (L3− denotes the totally deprotonated MEDTA). Results indicated that both complexation reactions were exothermic and driven by entropic force. The first stepwise reaction (Th4+ + L3− = ThL+) was mainly driven by entropy with minimal effect on enthalpy change. The second stepwise reaction (ThL+ + L3− = ThL22−) was more exothermic and showed less entropic change than the first stepwise reaction. The strong chelation of MEDTA would inhibit the hydrolysis of Th4+ and increase solubility.

Published in Nuclear Analysis

ISSN: 2773-1839 (Online)
Publisher: KeAi Communications Co., Ltd.
Country of publisher: China
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Nuclear engineering. Atomic power; Science: Physics: Nuclear and particle physics. Atomic energy. Radioactivity
Website: https://www.keaipublishing.com/en/journals/nuclear-analysis/

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