1987 Fiscal Year Final Research Report Summary
Fundanmental Studies of Fibrous Clay Minerals -- Dehydtation Mechanism, Surface Properties, and Acis Treatment.
| Project/Area Number |
60550449
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
資源開発工学
|
|---|
| Research Institution | Waseda University |
|---|
Principal Investigator |
OTSUKA Ryohei School of Science and Engineering, 理工学部, 教授 (80063204)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TSUTSUMI Sadao School of Education, 教育学部, 教授 (30063613)
|
|---|
| Project Period (FY) |
1985 – 1987
|
| Keywords | Sepiolite / Dehydration Mechanisw / Specific Surface Area / Pore Size Distribution / Cation Exchange Capacity / Acid Treatment / 非晶質繊維状珪酸ゲル |
|---|
| Research Abstract |
In order to develope the new unilization of fibrous clay minerals, especially sepiolite, fundamental studied were performed, giving the following results.
1. Dehydration mechanism of sepiolite The structural change of sepiolite due to dehydration, i.e., the forlding of the crystal lattice, occurs homogenecusly over the whole crystal. The rate of the first step dehydration of bound water is controlled by the water separation process from the Mg at the ribbon edge. The rest of the bound water diffuses out from the crystal through the lattice (the secons tep dehydration). The dehydration rate is determined by the water diffusion process in the folded channels.
2. Surface propertied of sepiolite (1) Specific surface areas tange from 443 m^2/g(Imisehir) to 231 m^2/g(Kores). pore size distribution curves indicate a sharp peak at about 20-30 A for all samples. (2) Cation exchange capacity (CEC) was measured by "Equilibrium Method". CEC range from 4.83 meg/100g(Vallecas) to 1.17 meg/100g(Kuzuu) when the pH of the solution is 7. The remarkable dependance of CEC on the pH of the solution indicate that the CEC of sepiolite is mainly caused by broken donds situated at the edges of the crystal lattice.
3. Acid treatment of sepiolite Firbous silica gel was obtained by HCL treatment of spepolete. As an exmaple, the product from the Kuzuu sepiolite, from which Mg was completely removed, shows a specific surface area of 470 m^2/g, an average pore size of 33.3 A, and a pore volume of 0.51 cc/g. These characteristics, together with a peculiar fibrous form, will make this silica gel a possible target of the new utilization.
|
