| Project/Area Number |
02640630
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
鉱物学(含岩石・鉱床学)
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| Research Institution | Yamaguchi University |
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Principal Investigator |
MIZOTA Tadato Yamaguchi Univ., Fac. of Engineering, Professor, 工学部, 教授 (10018666)
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| Co-Investigator(Kenkyū-buntansha) |
GOTO Seishi Yamaguchi Univ., Fac. of Engineering, Assistant Prof., 工学部, 助教授 (00016817)
IKEDA Ko Yamaguchi Univ., Fac. of Engineering, Assistant Prof., 工学部, 助教授 (00035057)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1990: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Zeolitic Water / Entropy of Water / Equilibrium Vapour Pressure / Zeolite / Entropy |
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| Research Abstract |
To clarify states of water in hydrous minerals, three instruments have been made and developed during this work, suchas equipment for temperature dependence of equilibrium water vapor pressure measurement (TDEP), adiabatic gas adsorption calorimeter (AGA) and adiabatic micro-calorimeter (AMC). TDEP was equipped with high precession digital manometer (MKS Baratron 127A) by improving the instrument initially developed by Mizota et al. (1989). Both AGA and AMC are controlled by a microcomputer for measurements and for data processing. The thermister-thermometer adopted for them has the temperature precision of 0.0001K. The high precision. enables accurate determination of hydration energy with relatively small amount of sample (0.11g). Hydration energies were measured for several natural zeolites and synthetic zeolites. Configurational entropy of molecular sieve 5A zeolite was obtained, for example, to be 50JK^<-1>mol^<-1> at around 45ﾟC, the value of which is comparable with those obtained by adiabatic heat capacity calorimeter from absolute zero-kelvine. Hydration enthalpy of these zeolites obtained from AGA method were -55kJ/mol(H20) which is consistently explained as a total of the heat of evaporation of water (about 44kJ/mol) and the hydration heat obtained from AMC. This indicates that enthalpy values derived through these three methods were cross-checked with each other. A remaining problem will be to improve the method of determining more accurately the dehydration amount of water for each of three instruments. TDEP is a suitable method for investigating, states of water molecules quantitatively, because both of the differential heat of adsorption of water and the configurational entropy can be measured at a temperature and at a hydration level of a hydrated material.
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