2000 Fiscal Year Final Research Report Summary
Remediation of contaminated soil by the combination of supercritical fluid extraction and electrochemical reaction.
| Project/Area Number |
11450296
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
反応・分離工学
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| Research Institution | Tohoku University |
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Principal Investigator |
YOKOYAMA Chiaki Institute for Chemical Reaction Science, Tohoku University, 反応化学研究所, 教授 (50150256)
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| Co-Investigator(Kenkyū-buntansha) |
IHARA Manabu Institute for Chemical Reaction Science, Tohoku University, 反応化学研究所, 助手 (90270884)
ARAI Masahiko Graduate School of Engineering, Hokkaido University, 大学院・工学研究科, 教授 (60125490)
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| Project Period (FY) |
1999 – 2000
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| Keywords | supercritical fluids / extraction / contaminated soil / electrochemical decomposition / remediation |
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| Research Abstract |
The purpose of this project was to develop a remediation process of contaminated soils by the combination of the supercritical fluid extraction and electrochemical reaction. The supercritical fluid extraction functioned to separate organic materials from contaminated soil, and the electrochemical reaction was applied for the complete decomposition of the extracted organic materials in organic solvents. The organic materials considered were polyaromatic hydrocarbons, polychlorinated hydrocarbons, and asphaltens. We firstly developed a semi-flow type supercritical fluid extractor, which can be used in the temperature range from room temperature to 750 K and pressures up to 50 MPa. The volume of the extractor was about 500 cc. The contaminated soil sample was put into a small container and set in the extractor. The high temperature and high pressure water was produced with a high pressure plunger pump and pre-heater, which was introduced into the extractor. The effluent from the extractor
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went through the pressure control valve and was collected into a sample corrector. After the extraction procedures, the remained sample was recovered from the extractor for analysis. In order to check the experimental apparatus and procedures, the solubility of benzene and dichlorobenzene were measured at 473 K and 573 K.From the comparison with the reference data of benzene, it was found that the present experimental procedure gives reliable results. In the next step, we used asphalten contaminated soil as the model materials of organic containing soil. It was found that the asphaltene can be separated completely by the extraction at 573 K and 30 MPa. The extractants were consisted from water soluble and water insoluble fractions. The water soluble fractions were extracted with solvent extraction. The solution obtained from the solvent extraction was introduced into the electrochemical cell directly, and the extracted organic materials were decomposed completely by the electrochemical reactions.
The theoretical study to investigate the solubility calculation method for the organic compounds in water and CO2 solvents was investigated. The quantitative structure and activity relationship equation was proposed for the solubility prediction for the supercritical CO2 and supercritical water. One of the advantages of this equation was that the information needed for the calculation is molecular structural data and melting temperature. With this equation, we can predict the solubility of dioxins in supercritical fluids quantitatively. Less
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Research Products
(10 results)
