The number of zeolites of the chabazite group besides naturally known phases of the group has been calculated by the simple method. The method has been proposed for the calculation by the combinatorial prediction of the pile of combinations of A-B and A-B-C rings of the group. According to the calculation, numerous number of distinct species of the chabazite group has been existed topologically. On the basis of the calculation after reduction of geometrical limitation of the crystal group by the Merlino's rule the new natural or synthetic phases of zeolites of the group may be expected to be found in the future.

抄録全体を表示

Dickite (two-layer polytype of kaolinite) was added to a natural amorphous aluminosilicate, allophane to reduce the barrier against nucleation of kaolinite (Al₂Si₂O₅ (OH) ₄) under several hydrothermal conditions arranged by an experimental design method, and high yield of kaolinite was obtained.
Dickite from Syokozan mine, Japan was mixed with allophane from Kanuma city, Japan to give the dickite/allophane weight ratios of 0.1/3.9, 0.4/3.6, and 2/2. Then, aluminum chloride (4, 8, and 16%), 3N-HC1 (0, 0.2, and 0.3ml), and 16 ml of distilled water were added to the 4 g of the powders. The starting suspension was heaed for 1-9 days at 200°, 220°, or 245°C in a Teflon pressure vessel under an autogenous vapor pressure. These factors and levels were arranged by the experimental design method.
Yield of kaolinite increased with increases in temperature, duration time, and amount of dickite. Even at a lower temperature (200°C, 9 days), more than 80% of starting allophane was changed into kaolinite by the 2/2 addition of dickite, whereas nearly 40% without addition. Other factors (amount of HC1 and AlCl₃·6H₂O) were less effective than that of the amount of added dickite. The peak at 670°C of derivative thermogravimetry which corresponds to dehydration of dickite was not changed by the hydrothermal treatment, whereas the peak at 500°C-550°C which corresponds to that of kaolinite became larger by the treatment. Therefore, it is concluded that even dickite with different layer stacking from kaolinite can promote the growth of kaolinite.

抄録全体を表示

A method for measuring the consecutive adsorption of phenolic acids was devised by using the batch technique. Both the consecutive adsorption and desorption characteristics of three phenolic compounds with one or two salicylic moiety and dierent molecular weights, salicylic acid, 2-hydroxy-3-naphthoic acid sodium salt and naphthochrome green, on allophanic clay were measured by changing pH and concentration.
The halloysitic and illitic clays were used as references. The amounts of adsorbed salicylic acid abruptly increased at relatively high pH conditions after the second repetition, which occured by chelating bondings with the surfaces of allophanic clay. The 2-hydroxy-3-naphthoic acid sodium salt and the naphthochrome green were, however, largely retained at low pH conditions, so the participation of other mechanisms than chelating bondings, such as ionic exchange, hydrogen bonding and/or physical bonding, were estimated.
The pH and concentration (C: M) dependency of the retention (n:μM/g) obeyed the following linearly multiple regression equation:
log (n)=a pH+b log (C)+c pH×log (C)+d pH²+e
where a, b, c, d and e were coefficient constants for a combination of a phenolic compounds and a clay sample at each repetition.

抄録全体を表示