Online ISSN : 1884-6440
Print ISSN : 0385-1036
ISSN-L : 0385-1036
32 巻, 6 号
選択された号の論文の7件中1~7を表示しています
特集:メソポーラス,ミクロポーラス媒体としての無機膜
総説
  • 藤田 悟, 稲垣 伸二
    2007 年 32 巻 6 号 p. 318-324
    発行日: 2007年
    公開日: 2015/06/18
    ジャーナル オープンアクセス
    Mesoporous materials, a new class of materials characterized by large specific surface areas and pore sizes between 2 and 50 nm, are obtained using templates. Especially, mesoporous organic-inorganic hybrid materials are fascinating because the incorporation of organic units in the pore walls provides numerous potential applications such as catalysis, separation, adsorption, sensor, gas storage and optical and electrical devices. This article presents the outline of synthesis and structure of organic-inorganic hybrid mesoporous materials. Emphasis is given to a variety of preparations of mesoporous films. Relevant uses of these films in diverse applications are discussed.
  • 吉宗 美紀, 原谷 賢治
    2007 年 32 巻 6 号 p. 325-331
    発行日: 2007年
    公開日: 2015/06/18
    ジャーナル オープンアクセス
    This paper reports the preparation of mesoporous carbon membranes by the pyrolysis of mesoporous aerogel membranes fabricated from a resorcinol-formaldehyde (RF) aqueous solution. The nitrogen adsorption-desorption measurement shows that the RF carbon membranes possess a well-developed mesoporous structure with a BET surface area of over 400 m2 g–1. In addition, mesopore diameters of RF carbon membranes can be controlled from 3.3 nm to 14 nm by changing the molar ratio of resorcinol to catalyst (R/C) from 100 to 400. The helium permeances of RF carbon membranes were independent of the feed pressure, indicating that there was no contribution of viscous flow to the total permeation. This result supports that the obtained RF carbon membranes are initially pinhole free. The permeation of H2, He, CH4, N2, CO2 and CF4 through the RF carbon membranes was predominantly governed by Knudsen diffusion.
  • 中坂 佑太, 多湖 輝興, 矢野 一久, 増田 隆夫
    2007 年 32 巻 6 号 p. 332-339
    発行日: 2007年
    公開日: 2015/06/18
    ジャーナル オープンアクセス
    The diffusivities of hydrocarbons within zeolite in gas phase have been measured widely. On the other hand, there have been few reports concerning measurements of the diffusivities of molecules within catalysts in the liquid phase as compared with those in the gas phase, because it is difficult to measure directly and continuously the change in the diffusate concentrations with time due to adsorption and diffusion into the catalysts in the liquid phase. In our recent research, we succeeded in developing a new method for measuring diffusivities within solid catalyst in liquid phase using Raman spectroscopy. Constant volumetric method was employed in this measurement, and diffusion mechanisms of hydrocarbons within solid catalyst were investigated by measuring separately intracrystalline diffusivity and partition factor. Intracrystalline diffusivity directly represents the mobility of molecules within pores. And the partition factor is the ratio of the diffusate concentration in solid catalyst to that in bulk phase, and means the concentration effect. Effective diffusivity is obtained by multiplying the intracrystalline diffusivity by the partition factor. In this manuscript, we review intracrystalline and effective diffusivities of hydrocarbons within porous solid catalyst in gas and liquid phases by introducing our recent research.
  • 野村 幹弘
    2007 年 32 巻 6 号 p. 340-346
    発行日: 2007年
    公開日: 2015/06/18
    ジャーナル オープンアクセス
    Hydrogen permeselective silica membranes prepared by using a counter diffusion CVD method had been investigated in the effects of deposition temperatures and those of γ-alumina substrates. Hydrothermal stable silica membranes were obtained between 550 and 600 ℃ of deposition temperatures for the TMOS (tetramethyl orthosilicate)/ O2 system. Silica layer deposited at the lower temperature was damaged due to compaction of the deposited silica, while γ-alumina layer (support of the silica layer) must be damaged for the higher deposition temperature. Addition of Ga to γ-alumina is one idea to improve the stability of the support. As a result, decrease of hydrogen permeance through the silica membrane by hydrothermal treatment was reduced. It is important to improve support stability to improve the permeation properties of the silica layer deposited on the support.
  • 佐々木 優吉
    2007 年 32 巻 6 号 p. 347-354
    発行日: 2007年
    公開日: 2015/06/18
    ジャーナル オープンアクセス
    Zeolite and mesoporous silica, which are representative nanoporous materials, have ordering pores in uniform nanometer size. Selective adsorption and molecular sieving properties of the nanoporous materials are useful for catalyst, adsorbent and gas separation membrane. Functional properties of the nanoporous materials must be dominated by the nanostructure. TEM observation is especially effective to analyze the nanostructure of nanoporous materials. Therefore it is expected that TEM observations become more important analysis method on this research field. However, generally interpretation of TEM images is not easy to understand for researchers who are shallow experience of the TEM observation. In this paper, the contrast formation principle of TEM image is explained and the nanostructure analysis for nanoporous materials using TEM is also introduced by showing the observation results of nanoporous materials.
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