巻号一覧
46 巻 (2007)
- 4 号 p. 194-
- 3 号 p. 147-
- 2 号 p. 105-
- 1 号 p. 3-
46 巻, 3 号
選択された号の論文の4件中1～4を表示しています
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鈴木 啓三, 高木 慎介, 佐藤 努, 米田 哲朗2007 年 46 巻 3 号 p. 147-155
発行日: 2007/08/16
公開日: 2011/09/20
ジャーナル フリーHighly purified montmorillonite (HP-Mont) was prepared to understand the original characteristics of montmorillonite by combined treatments such as sedimentation, super centrifugation, treating with alcohol solution, decarbonation with acetic acid-sodium acetate buffer solution, Na-exchange with sodium chloride solution. The prepared montmorillonite was comprehensively characterized, and the characteristics of HP-Mont were compared with commercial montmorillonite (Com-Mont) and summarized as follows;
1. Results of XRD, TG-DTA, CEC, LC measurements showed that the HP-Mont was extremely pure montmorillonite. Layer charge was 0.410 e.s.u./half unit cell, 30% of the layer charge was located in tetrahedral layers, and the rest was in octahedral layers.
2. After removal of quartz and soil organics, the HP-Mont showed white color in powder and transparent in aqueous suspension.
3. Aqueous suspension of the HP-Mont had high viscosity and the viscosity for 1.5% suspension of the HP-Mont was higher than that for 4.0% suspension of the Com-Mont.
4. Aqueous suspension of the HP-Mont was slightly acidic due to removal of sodium carbonate and calcium carbonate.
5. The planar size of the HP-Mont was comparatively smaller than that of the Corn-Mont, as the result of separation by supercentrifugation.
6. Zeta potential of the HP-Mont was slightly larger than that of the Corn-Mont, due to the result of removal of soluble salts.抄録全体を表示PDF形式でダウンロード (11200K) -
河野 元治, 小保方 寿峰2007 年 46 巻 3 号 p. 156-168
発行日: 2007/08/16
公開日: 2011/09/20
ジャーナル フリーGeochemical and mineralogical investigations of CaCO3 precipitation in Anraku hot spring of Kagoshima Prefecture were carried out to evaluate the effects of cyanobacteria on precipitation rates and polymorphism of CaCO3 minerals. The CaCO3 precipitates form surface sediments of the hot spring along water passage about 5m length and 10m width. These CaCO3 sediments consist mainly of aragonite (70-88 wt.%) with variable amounts of calcite, on which cyanobacterial biofilms were developed. Chemical analysis of the hot spring water collected along the water passage with intervals of 1.5m indicated that the water was highly supersaturated with respect to both aragonite and calcite with SI (log (IAP/K))=0.7-1.4. Such high SI values seem to be achieved mainly by the result of abiotic CO2 degassing and also by CO2 removal due to photosynthesis of cyanobacteria. To evaluate the effect of cyanobacteria, we performed experimental synthesis of CaCO3 minerals using the hot spring water in the systems with and without cyanobacteria (Phormidium sp.) isolated from the hot spring. The experiment was conducted at 25° for 10days under 4, 000Lx light condition. Results of the comparative experiment, it was found that the precipitation rates of CaCO3 in biotic system were enhanced by 1.9 to 32 times compared with the abiotic system due to the cyanobacterial photosynthesis which cause rapid increase in solution pH and also in saturation states. In addition, extent of aragonite formation was greatly induced up to 94-97 wt.% relative to abiotic system by possibly interaction with acidic proteins released from the cyanobacterial cells into the solution.抄録全体を表示PDF形式でダウンロード (16881K) -
小野 裕之, 和田 信一郎2007 年 46 巻 3 号 p. 169-175
発行日: 2007/08/16
公開日: 2011/09/20
ジャーナル フリーWe measured calcium and copper adsorptions from a 0.01 mol L-1 CaCl2 solution by three halloysite samples that were purified by size-fractionation and dithionite treatments. An allophanic clay and noncrystalline silica were used as references. The Ca and Cu adsorptions increased as pH increased and all of the added Cu was adsorbed at and above pH 6.3. The halloysite samples adsorbed significant amounts of Ca and Cu even at pHs<4, suggesting that these halloysites have surface negative charge arising from isomorphous substitution. The values of the natural logarithm of the selectivity coefficient for Ca-Cu exchange were around 5 at pHs<4 and exponentially increased to about 7 at pH6.5. The values for halloysite samples were markedly higher than the values reported for 2: 1 type layer silicates. Comparison of the adsorption percentage vs. pH curves of the halloysites and allophanic clay, and silica suggested that halloysite is superior to allophane and oxide minerals as an adsorbent in heavy metals-immobilization technology.抄録全体を表示PDF形式でダウンロード (4661K) -
田村 堅志2007 年 46 巻 3 号 p. 176-183
発行日: 2007/08/16
公開日: 2011/09/20
ジャーナル フリーPDF形式でダウンロード (11044K)
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