Highly selective encaging of carbon dioxide molecules in the mixed carbon dioxide and nitrogen hydrate at low temperatures

Ji Ho Yoon, Taro Kawamura, Michica Ohtake, Satoshi Takeya, Takeshi Komai, Yoshitaka Yamamoto, Hiroshi Emi, Mitsuhiro Kohara, Susumu Tanaka, Osamu Takano, Kazuo Uchida

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

The structural identification and guest compositions of the mixed CO 2 and N2 hydrates at low temperature conditions were investigated by both theoretical predictions and experimental measurements. From the model calculations, at very low temperatures, the highly CO 2-concentrated hydrates over 95 mol % CO2 on the basis of water-free concentration could coexist with the gas mixtures of low CO 2 concentrations in equilibrium. X-ray diffraction measurements of the hydrates formed with the gas mixture of 3.16 mol % CO2 and balanced N2 indicate that the formed hydrates at all conditions considered in this study were identified as structure I, whereas the model predicts a structural transition to structure II around 220 K. However, it was also found that the formed hydrate samples contain a considerable amount of hexagonal ice resulting from incomplete conversion of ice to the hydrates. The compositional analysis suggests that a favorable encaging of CO2 in the mixed hydrate can be obtained by the hydrate formation at low temperatures and relative amount of CO2 molecules in the mixed hydrates increases with a decrease of temperature.

Original languageEnglish
Pages (from-to)17595-17599
Number of pages5
JournalJournal of Physical Chemistry B
Volume110
Issue number35
DOIs
Publication statusPublished - 2006 Sep 7
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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