Contrasting mechanisms for CO2 absorption and regeneration processes in aqueous amine solutions: Insights from density-functional tight-binding molecular dynamics simulations

Hiromi Nakai, Yoshifumi Nishimura, Takeaki Kaiho, Takahito Kubota, Hiroshi Sato

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

CO2 chemical absorption and regeneration processes in aqueous amine solutions were investigated using density-functional tight-binding molecular dynamics simulations. Extensive analyses of the structural, electronic, and dynamical properties of 100 independent trajectories supported the contrasting mechanisms in the absorption and regeneration processes. In the CO2 absorption process, bicarbonate formed where the hydroxyl anion migrated through the hydrogen-bond network of water molecules, namely, by a Grotthuss-type mechanism. On the other hand, direct proton transfer from the protonated amine to the hydroxyl group of bicarbonate, which is called the ion-pair mechanism, was the key step to the release of CO2.

Original languageEnglish
Pages (from-to)127-131
Number of pages5
JournalChemical Physics Letters
Volume647
DOIs
Publication statusPublished - 2016 Mar 1

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Bicarbonates
regeneration
Hydroxyl Radical
Amines
Molecular dynamics
amines
molecular dynamics
Proton transfer
carbonates
Computer simulation
Anions
Hydrogen bonds
simulation
Trajectories
Ions
Molecules
Water
trajectories
hydrogen bonds
anions

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Physics and Astronomy(all)

Cite this

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abstract = "CO2 chemical absorption and regeneration processes in aqueous amine solutions were investigated using density-functional tight-binding molecular dynamics simulations. Extensive analyses of the structural, electronic, and dynamical properties of 100 independent trajectories supported the contrasting mechanisms in the absorption and regeneration processes. In the CO2 absorption process, bicarbonate formed where the hydroxyl anion migrated through the hydrogen-bond network of water molecules, namely, by a Grotthuss-type mechanism. On the other hand, direct proton transfer from the protonated amine to the hydroxyl group of bicarbonate, which is called the ion-pair mechanism, was the key step to the release of CO2.",
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T1 - Contrasting mechanisms for CO2 absorption and regeneration processes in aqueous amine solutions

T2 - Insights from density-functional tight-binding molecular dynamics simulations

AU - Nakai, Hiromi

AU - Nishimura, Yoshifumi

AU - Kaiho, Takeaki

AU - Kubota, Takahito

AU - Sato, Hiroshi

PY - 2016/3/1

Y1 - 2016/3/1

N2 - CO2 chemical absorption and regeneration processes in aqueous amine solutions were investigated using density-functional tight-binding molecular dynamics simulations. Extensive analyses of the structural, electronic, and dynamical properties of 100 independent trajectories supported the contrasting mechanisms in the absorption and regeneration processes. In the CO2 absorption process, bicarbonate formed where the hydroxyl anion migrated through the hydrogen-bond network of water molecules, namely, by a Grotthuss-type mechanism. On the other hand, direct proton transfer from the protonated amine to the hydroxyl group of bicarbonate, which is called the ion-pair mechanism, was the key step to the release of CO2.

AB - CO2 chemical absorption and regeneration processes in aqueous amine solutions were investigated using density-functional tight-binding molecular dynamics simulations. Extensive analyses of the structural, electronic, and dynamical properties of 100 independent trajectories supported the contrasting mechanisms in the absorption and regeneration processes. In the CO2 absorption process, bicarbonate formed where the hydroxyl anion migrated through the hydrogen-bond network of water molecules, namely, by a Grotthuss-type mechanism. On the other hand, direct proton transfer from the protonated amine to the hydroxyl group of bicarbonate, which is called the ion-pair mechanism, was the key step to the release of CO2.

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