Sauconites were synthesized hydrothermally from a homogeneous gel with stoichiometric chemical composition in a temperature range of 100-200°C for up to 14d at autogenous pressure. The synthetic products were characterized by XRD, SEM, TEM, ICP-AES, FT-IR and XPS. The well-crystallized sauconite without impurities was obtained after 100°C treatment. At 150 and 200°C, sauconite coexisted with small amount of hemimorphite (Zn₄Si₂O₇ (OH) 2·H₂O) and willemite (Zn₂SiO₄). The octahedral coordination of Zn in synthesized sauconite was confirmed by FT-IR and XPS spectra, comparing with those of natural mica containing Zn in the octahedral layer (hendricksite). The FT-IR spectra of synthetic sauconite showed the characteristic bands at 660cm^-1 for Zn-O vibration and 3635cm^-1 for 3Zn-OH stretching in the octahedral sheets, which are comparable to those of hendricksite. The Zn (3p) peak of sauconite in XPS spectrum was observed which corresponded with that of hendricksite. These results indicated that Zn in sauconite was coordinated octahedrally as Zn in hendricksite.

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Adsorption and desorption behaviors of toluene were investigated for porous pillared clays, such as organic-pillared clays (silica-or silica/alumina-pillared kanemite, and porous clay nanocomposites) and compared with those of silicalite, β-zeolite, ordered mesoporous silica, and silica aerogel to examine their abilities as adsorbents for volatile organic compounds (VOCs). Toluene adsorption isotherms of these materials showed that all the porous pillared clays adsorbed toluene in the relatively low pressure region (p/p0<0.01) and much higher than the other porous materials, owing to the flat toluene molecule. No other significant differences were observed in the adsorption rates of the porous pillared clays. DTA-TG analyses of the porous pillared clays revealed a weak ability to entrap toluene up to 373K. Lower retention of VOCs at raised temperatures allows the porous pillared clays to regenerate more easily for repeated use.

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The origins of the parent materials in the reddish and/or yellowish fine textured soils developed in the hilly area surrounding Fukui plain, Fukui Prefecture, Central Japan were examined mainly by the measurement of the ESR-signal intensities associated with the oxygen vacancies in the fine quartz in these soils. The results are summarized as follows:
The ESR-signal intensities were 11.0 to 14.0 (unit, 1.3×10¹⁸ spin kg^-1) and were very high, in all the horizons of Ohshibayama soil. These values suggested that the parent materials in all the horizons of this soil were influenced by the eolian dust brought from the Precambrian sediments in the northern part of Asia continent as stated in the case of Jingaoka soil in the Ka-Etsu plateau which was reported previously. The parent materials in the surface soils of other two soils tested in the present study were also influenced by the eolian dust brought from the Precambrian sediments area in the northern part of the Asia continent with the NW-winter monsoon during MIS2 (24-11 thousands years ago, Last Glacial Maximum). On the other hand, the ESR-signal intensities in the fine quartz in the subsoils of the Daianzenji and the Kazatani-pass soils were very low, and suggested that the parent materials in these subsoil were derived from the autochthonous Miocene tuffereceous sediments, which was coincident to the results of the previous clay-mineralogical studies. The parent materials in the middle depth horizons of four soils tested in the present study were the mixture of the autochtonous sediments and the eolian dust brought from the Precambrian sediments in the northern part of the Asia continent, because the ESR-signal intensities in them were 6.3 to 8.7 unit, and were relatively low.

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Fourteen surface soil samples were collected from hilly region in Shan State (Southern), inland valley and meander floodplain in Mandalay Division, and deltaic plain in Bago and Yangon Divisions of Myanmar and subjected to clay mineral analysis. The clay mineralogical composition of the soils was found to have a good relationship with physiography as a total of the topography, parent material and soil type. Soils on the hilly region in Shan State (Southern) were characterized by the high kaolinite content in the clay fraction, whereas soils on the meander floodplain of the Ayeyarwady River system were dominated by mica. 2: 1-type expansible minerals (vermiculite, smectite, and mica/vermiculite/smectite-mica/smectite mixed-layer mineral) considered as the transformation products of mica were predominant in soils on the inland valley in Mandalay Division. Soils on the deltaic plain of the Ayeyarwady River system and on the meander floodplain of the Sittang River were characterized by major amounts of kaolinite with considerable amounts of chlorite-vermiculite intergrade or some amounts of mica. Inherent potentiality of the soils was assessed based on the type and amount of clay minerals. The assessment showed a large variability in the inherent potentiality of the soils, which is useful to effective management of soil for crop production.

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Five samples of alluvial soils and 3 samples of grey degraded soils, both derived from the sediments of the Thaibinh River system in the Red River Delta, northern Vietnam, were subjected to clay mineralogical analysis in addition to measurement of pH, organic matter content and particle-size distribution. The pH was comparable between the two soil types. In contrast, the organic matter and clay contents were remarkably lower for grey degraded soils than for alluvial soils. Predominant clay minerals in both soil types were mica and kaolinite; the mica content was higher for alluvial soils while the kaolinite content was higher for grey degraded soils. Chlorite-vermiculite intergrade was detected only in grey degraded soils, whereas vermiculite was present in alluvial soils instead. Absence of goethite in grey degraded soils might be a cause of their grey color. A sign of degradation on the amount (clay content) and type (clay mineralogical composition) of clay minerals was indicated in grey degraded soils in the Red River Delta, leading to decrease in the organic matter content and then to decline in the soil fertility.

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