巻号一覧
33 巻 (1993 - 1994)
- 4 号 p. 181-
- 3 号 p. 130-
- 2 号 p. 59-
- 1 号 p. 3-
33 巻, 3 号
選択された号の論文の3件中1～3を表示しています
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前野 昌弘, 鐘尾 浩一, 野納 敏展, 藤川 英樹1993 年 33 巻 3 号 p. 130-137
発行日: 1993/12/30
公開日: 2011/09/20
ジャーナル フリーCa-montmorillonite from Vici, Oklahoma, U.S.A. is treated with 15% and 35% sulfuric acid at 70°C for 36 hours. With increasing hours, chemical change and morphological alteration are estimated as follows. At first stage, the primary 40Å micropores develop with the extraction of interlayer Ca. At second stage, larger micropores are made as the result of the leaching of octahedral Mg, Fe and Al. The specific surface area becomes maximum of 500m2/g at about 24 hours in case of 15% sulfuric acid treatment and 360m2/g at 9 hours in case of 35% sulfuric acid treatment. At final stage, the primary 40Å micropores disappear and secondary larger micropores remain. As the result, the specific surface area decreases from 360 to 300m2/g in case of 35% sulfuric acid. It is considered that this alteration is caused by the decomposition of montmorillonite structure and the formation of amorphous silica during sulfuric acid treatment.抄録全体を表示PDF形式でダウンロード (3886K) -
吉田 募1993 年 33 巻 3 号 p. 138-145
発行日: 1993/12/30
公開日: 2011/09/20
ジャーナル フリーSolidification of cotton fabric resulting from rinsing and drying processes was studied by means of apparent density measurements on disk-formed cotton fiber, conductometry of rinsing liquors, and electron microscopy of smectite flakes and cotton fibers. Loose cotton fibers collected by cutting a towel was used as the model sample for the cotton fabrics.
The rinsing of the sample by city water brought the highest apparent density at dried state. The lowest apparrent density was obtained in the case of rinsing the sample with commercial softening agent. Smectite suspensions yielded the intermediate values of apparent density between them. In the case of rinsing with distilled water, the apparent density decreased accordingly with the increasing volume of the rinsing liquor. Electron microscopy of the smectite flakes associated with cotton fibers showed preferential contamination with many fine particles which originated from impurities in the city water used for rinsing liquor.
Considering the drying process, it is elucidated that the solidification of cotton fabric is developed by solid bridge formation between the fibers. The solid bridges mainly originated from the impurities in the residual rinsing liquor in the fabric. For smectite and commercial softening agent, the following effects are demonstrated: Smectite prevents the solid bridge formation between the fibers precipitating particularly the impurities in the residual rinsing liquor at its own surface. The commercial softening agent, as the drying process proceeds, gather the residual rinsing liquor into the small pores in the fabric, at which the impurities accumulate resulting a bridgeless fabric.抄録全体を表示PDF形式でダウンロード (8489K) -
酸性部位と酸性発現機構松枝 直人, 呉 徳意, 逸見 彰男, 吉永 長則1993 年 33 巻 3 号 p. 146-151
発行日: 1993/12/30
公開日: 2011/09/20
ジャーナル フリーThe nature of the surface acidity of layer silicates with no layer charge is not well understood compared to that of the silicates with the charge. The objectives of this study were to characterize the surface acidity of four minerals (pyrophyllite, talc, kaolinite, and lizardite), and to elucidate the origin of the acidity of such ‘neutral’ minerals. The Hammett acid function (Ho) values and surface acid strength of the four minerals did not change with their exchangeble cation species. The degrees of the reduction in their acid strengths due to increase in relative humidity were smaller than the case of montmorillonite. In any conditions, acid strengths of dioctahedral minerals were greater than those of trioctahedral minerals. More than 70% of the external surfaces of the minerals were covered by methyl red, indicating that the acid sites distributed mostly in the external surfaces of the minerals. Both of pre-treatments by 1% sodium hexametaphosphate and by 1mM NaOH reduced the methyl red adsorption, but the acid strengths did not change after the NaOH treatment. From above results, we concluded that the acid sites of the ‘neutral’ minerals were the Lewis type, and derived from their ability to accept electrons due to the neutral layer compositions. We also concluded that the ability was related to enlargement of octahedral sheet in planer direction and elongations of some chemical bondings. The enlargement and elongations occur as a result of adjustment of misfit between tetrahedral and octahedral sheets, especially for dioctahedral minerals.抄録全体を表示PDF形式でダウンロード (835K)
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