TANSO
Online ISSN : 1884-5495
Print ISSN : 0371-5345
ISSN-L : 0371-5345
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Volume 2014, Issue 262
Displaying 1-6 of 6 articles from this issue
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Research Papers
  • Preparation of activated carbon with high surface area using crab shell and shochu waste and the development of methane storage technology
    Akihiro Yamashita, Yosuke Mori, Tatsuya Oshima, Yoshinari Baba
    Article type: Research Paper
    2014 Volume 2014 Issue 262 Pages 53-58
    Published: April 01, 2014
    Released on J-STAGE: May 01, 2014
    DOIhttps://doi.org/10.7209/tanso.2014.53
    JOURNAL FREE ACCESS
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    Methane gas is an energy alternative to petroleum. However, the two conventional methods of storing methane gas, as Liquefied Natural Gas (LNG) and Compressed Natural Gas (CNG), involve a high degree of risk in terms of safety. To develop a high-safety and low-cost method of storing methane gas, we examined its adsorption on activated carbon newly prepared from biomass waste (crab shell and shochu waste) by chemical activation with K2CO3. The activated carbons prepared from the mixture of crab shell and shochu waste exhibited a maximum specific surface area of 3212 m2/g as measured by nitrogen gas adsorption, which is more than double that of commercially available activated carbon. The adsorption isotherms of methane gas at 25 °C were measured using the new activated carbons and the results revealed that their adsorption capacities for methane gas were particularly influenced by their micropore volume.
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  • Preparation of few-layer graphene by the hydroxylation of potassium-graphite intercalation compound
    Takuya Wada, Takuya Yasutake, Akira Nakasuga, Taro Kinumoto, Tomoki Tu ...
    Article type: Research Paper
    2014 Volume 2014 Issue 262 Pages 59-62
    Published: April 01, 2014
    Released on J-STAGE: May 01, 2014
    DOIhttps://doi.org/10.7209/tanso.2014.59
    JOURNAL FREE ACCESS
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    Few-layer graphene was prepared from the potassium-graphite intercalation compound (KC8) by hydroxylation. In an oxidative atmosphere, KC8 decomposes from its initial structural stage to a second or third stage. However, when KC8 was hydroxylated by dropping a small amount of water onto it in a nonoxidative atmosphere, the KC8 exfoliated with a disruption of the stage structure and agglomerated graphene was obtained. Sonication of this agglomerated graphene in water yielded few-layer graphene. It was found that dropping small quantities of water onto KC8 is effective for achieving graphene with just a few layers.
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Short Paper
  • Low temperature pyrolysis of polyimide films in air
    Koji Tamada, Takashi Kobayashi, Akihiko Matsumoto, Tsutomu Takeichi, R ...
    Article type: Short Paper
    2014 Volume 2014 Issue 262 Pages 63-66
    Published: April 01, 2014
    Released on J-STAGE: May 01, 2014
    DOIhttps://doi.org/10.7209/tanso.2014.63
    JOURNAL FREE ACCESS
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    Carbon films were prepared from polyimide (PI) films by heat-treatment at low temperature in air. Porous pyrolyzed films were obtained by maintaining the PI films at 500∼560 °C for ten minutes in air. It was shown that heat-treatment in air is advantageous for the production of porous films with low energy and low cost. Furthermore, the pore size of the films was distributed between 1 nm and 6 nm, having not only micropores but also mesopores. This is very different from material produced by heat-treatment in nitrogen between 700 °C and 900 °C, where micropores are predominantly formed. It is expected that the porous films prepared by the heat-treatment in air are useful for the adsorption of a wide range of molecules other than small molecules.
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Integrated Paper
  • Thermodynamics of nano-porous carbon materials as adsorbents and electrochemical double-layer capacitor electrodes
    ―Implications from computer simulation studies―
    Kenji Kiyohara, Hiroshi Shioyama, Kinji Asaka
    Article type: Integrated Paper
    2014 Volume 2014 Issue 262 Pages 67-75
    Published: April 01, 2014
    Released on J-STAGE: May 01, 2014
    DOIhttps://doi.org/10.7209/tanso.2014.67
    JOURNAL FREE ACCESS
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    Thermodynamics in a nano-porous environment is different from that in the bulk. Adsorption of molecules in nano-porous carbon materials has been intensively studied and their characteristic features such as capillary condensation have been understood from the thermodynamic aspects. We extended the thermodynamic argument to the case where nano-porous carbon materials are used as electrochemical double-layer capacitor electrodes by performing Monte Carlo simulations in the constant-voltage grand-canonical ensemble. In this paper, we discuss the applications of nano-porous carbon materials both as adsorbents and as electrodes on the same thermodynamic basis in a unified manner. The characteristic features of nano-porous carbon materials such as the anomalous pore size dependence of capacitance, voltage-induced expansion of nano-porous carbon electrodes, phase transitions, and selective adsorption are understood in terms of the balance between the van der Waals or electrostatic interaction and the volume exclusion interaction inside them.
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Recent Doctoral Thesis
  • Study on physicochemical properties of oxygen gas and oxides in molten salts
    Yuya Kado
    2014 Volume 2014 Issue 262 Pages 80-82
    Published: April 01, 2014
    Released on J-STAGE: May 01, 2014
    DOIhttps://doi.org/10.7209/tanso.2014.80
    JOURNAL RESTRICTED ACCESS
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    A boron-doped diamond (BDD) electrode was examined as an oxygen evolution electrode in molten chlorides. It was confirmed that the BDD electrode has a potential to be employed for a stable oxygen evolution electrode in molten LiCl-KCl systems with any compositions below 773 K. However, in the melt containing CaCl2 such as LiCl-CaCl2, apparent degradation of the electrode was observed. In addition, the standard formal potentials of O2/O2− were measured by emf measurement with the BDD electrode and activity coefficients of oxide ion were determined in molten LiCl-KCl systems. The standard formal potential of O2/O2− is more positive and the activity coefficient of oxide ion is lower in the melt which has a larger content of LiCl. Moreover, the Li2O solubility was measured by electrochemical method. The melt with a larger content of LiCl has a higher solubility of Li2O. Thus, this study has given beneficial data for thermodynamic consideration on thermochemical and electrochemical processes involving oxygen gas and/or oxide ion such as reduction processes of metal oxides in molten LiCl-KCl systems.
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