1999 Fiscal Year Final Research Report Summary
Study on the characterization of a unique smectite disconvered in soil of Java Island
| Project/Area Number |
10660064
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Plant nutrition/Soil science
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
TOKASHIKI Yoshihiro Faculty of Agri., University of the Ryukyus, Professor, 農学部, 教授 (70045128)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Smectite / Mixed layer mineral / Paleudult / Halloysite / Halloysite / Beidellite |
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| Research Abstract |
In a Paleudult of Java Island, there was a clay mineral indicating a mixed layer Mineral which gave 15.51Å peak (in the range of 14.61Å and 16.37Å) on Mg^<2+> -air dry and a 20.55Å peak on Mg^<2+> -glycerol solvation. On K^+-saturation, the mineral showed an 11.87Å peak and this peak was continuous to 7.53Å.
Futhermore, on sequential heating, the peak gradually shifted and finally shifted completely to 10.05Å at 550℃ in X-rav diffraction (XRD). A peak of 7.53Å was also observed in both Mg^<2+>- and K^+-saturated clays which disappeared after heating at 550℃. The objective of this study was to investigate the characteristics of this mineral.
The 060 peak was 1.50Å and suggests the dioctahedral smectite. The Greene -Kelly test on the clay sample suggests beidellite. Formamide solvation that caused a swelling of the 7.53Å peak to 10.05Å suggests the presence of halloysite. The 5M NaOH treatment resulted in a collapse of the 7.53Å peak and remained at a sharp neak of 15.51Å (in Ms^<2+>-saturated clay). The presence of hallovsite was also supported by a SiO_2/Al_2O_3 molar ratio of NaOH extractable materials. The NaOH treatment also resulted in an increase of the 11.87Å peak (in K^+-saturated clay) to 13.49Å.
According to the mineralogical and chemical properties of the clay sample we consider that the mineral is hallovsite/beidellite mixed laver mineral.
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