TY - JOUR
T1 - Influence of amino acids on the mobility of iodide in hydrocalumite
AU - Wang, Mengmeng
AU - Akamatsu, Hirofumi
AU - Sasaki, Keiko
N1 - Funding Information:
Funding: This research was funded by Japan Society for the Promotion of Science (JSPS) KAKENHI research grants (Grant Nos. JP19H00883) and Kyushu University Progress 100 (Grant Nos. Invitation program for top global researchers) Strategic partnership acceleration (FY2020-2022).
Funding Information:
Acknowledgments: The authors wish to acknowledge the Research Institute for Information Technology at Kyushu University, the China Scholarship Council which provide scholarship for M.W. We also want to express our appreciation to the editors of Minerals and reviewers.
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2021/8
Y1 - 2021/8
N2 - In the cement system, hydrocalumite is a candidate adsorbent for low-level129 I anionic species. However, the stability of hydrocalumite after immobilizing I− is unclear when they are exposed to pedosphere characterized by organic substances derived from living organisms. In the present work, five amino acids were selected as simplified models of natural organic substances under alkaline conditions. L-cysteine (H2 Cys) and L-aspartic acid (H2 Asp) accelerated the release of I− from I-hydrocalumite through ion-exchange. Ion-exchange of Cys2− with I− in I-hydrocalumite was faster than Asp2−, and the interlayer spacing (d003 ) of Cys-hydrocalumite was smaller than that of Asp-hydrocalumite. DFT simulations not only supported the above results but also predicted that there was a positive correlation between the formation energies and interlayer spacings of amino acids intercalated hydrocalumite, depending on the configurations. Moreover, in the DFT predictions, the interaction between amino acids and metallic hydroxide layers was responsible for the formation of hydrogen bonds and Ca-O chemical bonds between the-COO− groups and [Ca2 Al(OH)6 ]+ . The other three amino acids did not show intercalation through ion-exchange. The stability of I-hydrocalumite is influenced differently by coexisting amino acids, depending on the ionic sizes, charge numbers, and hydrophilicity, which cause the second contamination.
AB - In the cement system, hydrocalumite is a candidate adsorbent for low-level129 I anionic species. However, the stability of hydrocalumite after immobilizing I− is unclear when they are exposed to pedosphere characterized by organic substances derived from living organisms. In the present work, five amino acids were selected as simplified models of natural organic substances under alkaline conditions. L-cysteine (H2 Cys) and L-aspartic acid (H2 Asp) accelerated the release of I− from I-hydrocalumite through ion-exchange. Ion-exchange of Cys2− with I− in I-hydrocalumite was faster than Asp2−, and the interlayer spacing (d003 ) of Cys-hydrocalumite was smaller than that of Asp-hydrocalumite. DFT simulations not only supported the above results but also predicted that there was a positive correlation between the formation energies and interlayer spacings of amino acids intercalated hydrocalumite, depending on the configurations. Moreover, in the DFT predictions, the interaction between amino acids and metallic hydroxide layers was responsible for the formation of hydrogen bonds and Ca-O chemical bonds between the-COO− groups and [Ca2 Al(OH)6 ]+ . The other three amino acids did not show intercalation through ion-exchange. The stability of I-hydrocalumite is influenced differently by coexisting amino acids, depending on the ionic sizes, charge numbers, and hydrophilicity, which cause the second contamination.
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U2 - 10.3390/min11080836
DO - 10.3390/min11080836
M3 - Article
AN - SCOPUS:85111592393
VL - 11
JO - Minerals
JF - Minerals
SN - 2075-163X
IS - 8
M1 - 836
ER -