巻号一覧
42 巻 (2002 - 2003)
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42 巻, 1 号
選択された号の論文の6件中1～6を表示しています
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佐伯 和利, 中川 啓, 和田 信一郎, 柴田 雅博, 広城 吉成, 神野 健二2002 年 42 巻 1 号 p. 1-5
発行日: 2002/08/24
公開日: 2011/09/20
ジャーナル フリーThe Gains-Thomas ion exchange selectivity coefficients, KGT of Fe2+ and Mn2+ on Ca-saturated bentonite (Kunigel V-1) were determined in an oxygen free condition in order to grasp the behaviors of these ions in anaerobic environments. This bentonite sample contained 48%(W/W) of montmorillonite. Maximum adsorbed Ca was 0.31 mmol g-1 of bentonite. The average ion exchange selectivity coefficients: KGT of Fe2+ to Ca-bentonite was 1.09, with a variation of 0.64-1.40, regardless of the charge fractions of Fe2+ adsorbed on the surface sites: EFe indicating that the selectivity of Fe2+ to the suface of the mineral was similar to that of Ca2+. These results implied that the solution systems composed of the Fe (II)-bentonite and the Ca-bentonite can be regarded as an thermodynamically ideal behaviors. The average KGT values of Mn2+ in Ca-bentnite also approximated 1.44 with a range of 0.78-2.04, confirming that Mn2+ can be uniformaly adsorbed on the surface of the clay mineral with the similar selectivity to alkaline-earth ions.抄録全体を表示PDF形式でダウンロード (813K) -
増子 貴胤, 坂本 尚史2002 年 42 巻 1 号 p. 6-14
発行日: 2002/08/24
公開日: 2011/09/20
ジャーナル フリーIt is well known that grinding of crystalline material cause a structural degradation and finally produce an amorphous phase. The amorphous phase thus prepared is expected to have a high reactivity under hydrothermal conditions. In the previous study, one of the authors reported that grinding treatment significantly increase the hydrothermal reactivity of talc, and aluminum bearing layer silicates was easily formed from ground talc by the hydrothermal treatment with AlCl3 solution.
In the present study, original and well ground sepiolite from Kuzu, which is non-crystalline on an XRD pattern, was treated hydrothermally with Al (NO3) 3, NaAlO2, and NaOH solutions. As a result, in Al (NO3) 3 solution, tri-octahedral smectite, di-octahedral smectite, and kaoline mineral are formed successively from both ground and original sepiolite with increasing Al (in solution)/Si (in sepiolite) ratio. In NaAlO2 and NaOH solution, both sample transformed into trioctahedral smectite and serpentine minerals with increasing the concentration of the solution. The kaolin mineral and the serpentine mineral formed from ground sepiolite are different from those from original sepiolite in the polytype and morphology.
These results reveal that the crystallinity of sepiolite is not effective in the reactivity in hydrothermal condition, because the nano-scale nature of sepiolite may dominate the hydrothermal behavior. It is also concluded, however, that the crystallinity of sepiolite has influence on the selection of reaction process in the hydrothermal transformations.抄録全体を表示PDF形式でダウンロード (8798K) -
地下 まゆみ, 北川 隆司, 池見 典子2002 年 42 巻 1 号 p. 15-20
発行日: 2002/08/24
公開日: 2011/09/20
ジャーナル フリーThe Au-decoration technique of electron microscopy was applied to the crystal surfaces of pyrophyllite and kaolinite collected from the Uku pyrophyllite deposit in Abu-Susa district, Yamaguchi Prefecture. The specimens composed of pyrophyllite and kaolinite exclusively exhibited malformed step growth patterns and polygonal spiral growth patterns. Saw-tooth step patterns, which are formed by dissolution, were also observed.
The crystals with malformed layer by layer step growth patterns are corresponded to pyrophyllite, they with polygonalspiral growth pattern and/or saw-tooth step patterns are indicated kaolinite crystals.
It is considered from these observation that kaolinite was formed before pyrophyllite grew under the hydrothermalalteration.抄録全体を表示PDF形式でダウンロード (8868K) -
田崎 和江, 朝田 隆二, 池田 頼正2002 年 42 巻 1 号 p. 21-36
発行日: 2002/08/24
公開日: 2011/09/20
ジャーナル フリーBiofilms quickly occur on the water surface, associated with Fe-bacteria, such as Leptothrix sp., Gallionella sp. and Toxothrix sp. are the most common pioneering species in microbial communities. The bacterial colonies form, Fe-rich biofilms within a few days which is active oxic zone of the top water surface. Biofilms are composed of amorphous iron hydroxides, goethite, ferrihydrite and schwertmannite Fe8O8(OH) 6S04 (2.5 and 1.5 Å) are found both in natural system and cultured solution. SEM-EDX, TEM and atomic-force microscopy showed the formation processes of Fe-rich biofilms with sub-micron rugged structure on the primitive stage. In this paper biomineral structure of Fe-rich biofilms collected from underground water at three places was described. The structure is affected by the water physical and chemical environment (anaerobic or oxidized condition), bacterial species, water chemical composition, and species interactions. The old idea of the biofilms is simply microbes suspended in a homogeneous, but in this study variety of microorganisms with Fe-rich cell was revealed. Brownish black biofilms grow on the surface of underground water in the Kakuma Campus of Kanazawa University, are of predominantly iron oxidizing bacteria, such as Leptothrix sp., Gallionella sp. and Toxothrix sp. The biofilms use ferrous ions as their energy source through the oxidation into ferric ions. TEM of the biofilms have revealed mucoid substances of bacteria, like polysaccharides are effective for adhesion of iron hydroxides produced through biomineralization of various bacterial communities. The quick condensation process of ordered iron bacterial colonies considered to be a factor for increasing the thickness of biofilms. This is the first time oriented Fe-bacterial sheet/nets in the colonies have been found in biofilms within a few days aging time. The formation mechanism of biofilms on the water surface can be apply science to implants to be placed in the human body in biomedical applications, such as catheter, heartlung machine, and contact lenses.抄録全体を表示PDF形式でダウンロード (39745K) -
中島 善人2002 年 42 巻 1 号 p. 37-50
発行日: 2002/08/24
公開日: 2011/09/20
ジャーナル フリーPrinciples of the measurement of the diffusion coefficients by the pulsed-field-gradient (PFG) proton nuclear magnetic resonance (NMR) spectroscopy were reviewed. In the PFG NMR method developed by Stejskal and Tanner, the randomwalk displacement of the target nuclei is encoded as a phase of the spin precession and detected as the decrease in the NMR spin-echo signal intensity with increasing pulsed magnetic field gradients. An example of the measurement of H2O selfdiffusion in water-rich hectorite gels was shown. The obtained diffusion data were explained by a model that free or unbound H2O molecules diffuse in the porous gel by avoiding the randomly placed obstacles (clay platelets sandwiched by bound or immobilized H2O layers). Because nondestructive, quick, high-precision, and three-dimensional measurements of self-diffusion tensors of H2O are possible, PFG NMR is a powerful tool in the clay science.抄録全体を表示PDF形式でダウンロード (6638K) -
松枝 直人2002 年 42 巻 1 号 p. 51-58
発行日: 2002/08/24
公開日: 2011/09/20
ジャーナル フリーPDF形式でダウンロード (15886K)
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