| Project/Area Number |
15310047
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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 |
Environmental technology/Environmental materials
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| Research Institution | The University of Tokyo |
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Principal Investigator |
HASHIMOTO Kazuhito The University of Tokyo, School of Engineering, Professor, 大学院・工学系研究科, 教授 (00172859)
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| Co-Investigator(Kenkyū-buntansha) |
IRIE Hiroshi The University of Tokyo, School of Engineering, Research Assistant, 大学院・工学系研究科, 助手 (70334349)
OHNISHI Nobuo RCAST, Researcher, 先端科学技術研究センター, 科学技術振興特任研究員(常勤形態) (00361684)
SUNADA Kayano Kanagawa Academy of Science and Technology, Special Research Laboratory for Optical Science, Researcher, 光科学重点研究室, 研究員 (20311433)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥15,800,000 (Direct Cost: ¥15,800,000)
Fiscal Year 2005: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2004: ¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 2003: ¥8,200,000 (Direct Cost: ¥8,200,000)
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| Keywords | TiO_2 photocatalyst / Polluted soil / Solar light / Environmental purification / VOCs / Photocatalytic sheet / 汚染土壌現地浄化法 / 吸着剤 / VOC / 土壌汚染 / 環境改善 / 有機塩素化合物 / 吸着剤(活性炭) |
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| Research Abstract |
Volatile chlorinated organic compounds (VCOCs) such as trichloroethylene (TCE) and tetrachloroethylene (PCE) have been widely used as solvent for dry cleaning of clothes, washing of semiconductors, and so on. They have been disposed out of control, causing the soil and groundwater pollutions. These pollutions are serious environmental problems because these chemicals are carcinogenic and toxic. We have designed and proposed a treatment system for soil polluted by VCOCs utilizing "TiO_2 photocatalyst sheets". The sheet consists of TiO_2 powder and adsorbent (activated carbon). The adsorbent traps VCOCs evaporated from the soil and also traps undesirable intermediates such as phosgene and dichloroacetyl chloride (DCAC) observed by TiO_2-mediated photocatalytic degradation of TCE in gas phase.
The system utilizing the photocatalyst sheets and solar light was investigated in the actual polluted field. One field was an old factory site, and the other was an active cleaning shop. The polluted
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soil in the old factory site was mixed with "Hotsoil (CaO)" to volatilize the chemicals (PCE), and the photocatalyst sheets were covered over the soil. As the status has been kept for three weeks, the photocatalyst sheets have illuminated by solar light for the period. PCE concentrations in gas phase of the soil decreased drastically for initial two days, and they were below detectable limit after seven days. The PCE concentrations in the soil were also below 0.01 mg/L whose concentration is Japan's environmental limit of PCE. The other system to treat the polluted soil under the ground in the active cleaning shop was an aspiration treatment of VCOCs gases from the polluted soil through the well by vacuum pomp. The aspirated gases were led to an adsorption device having the photocatalytic sheets. When the sheets saturated by VCOCs gas, we hanged out the sheets under solar light and reused them in the device. The results in the actual fields show that the system using photocatalyst sheets and solar light is effective on the treatment of the soil polluted by VCOCs. Less
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