| Project/Area Number |
16360445
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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 |
Earth system and resources enginnering
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| Research Institution | Kyushu University |
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Principal Investigator |
SASAKI Keiko Kyushu University, 大学院・工学研究院, Associate Professor (30311525)
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| Co-Investigator(Kenkyū-buntansha) |
KONNO Hidetaka Hokkaido University, 大学院・工学研究科, Professor (50002316)
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| Project Period (FY) |
2004 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥15,900,000 (Direct Cost: ¥15,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2007: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2006: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2005: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2004: ¥7,000,000 (Direct Cost: ¥7,000,000)
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| Keywords | Biogenic minerals / groundwaters / soils / remediation / マンガン酸化真菌 / 重金属イオン / 環境修復 / 地下水・土壌汚染 |
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| Research Abstract |
In the permeable reactive barrier(PRB)column experiments, the contribution of sulfate-reducing bacteria and selenate-reducing bacteria on the groundwater remediation was confirmed. The SEM-EDX observation directly indicates the precipitation of sulfides in residual materials after decomposition of used column. Additionally the sulfur isotopic ratio of δ^<34>S indicated significant decrease in influent and effluent of PRB, which is an evidence of the contribution of sulfate-reducing bacteria to the reaction in the PRB column. During the microbial precipitation of sulfides, arsenate would be co-precipitated with iron sulfides on the surface of iron granules(ZVI), which is a reactive material in PRB, and HCO_3 is generated after microbial decomposition of carbon sources giving the elevation of alkalinity in the effluent. Dissolved Ca^<2+>and Mg^<2+>is precipitated as carbonates with HCO_3 , which is supported also by SEM-EDX observation. The X-ray photoelectron spectroscopy(XPS)provided that arsenic was immobilized as arsenate or arsenate neither as elemental arsenic nor arsenide on the ZVI. In case of Se immobilization, selenate was reduced to elemental selenium and selenide on the surface of ZVI, which was confirmed by XPS and Raman spectroscopy. Manganese-oxidizing microorganisms, which are aerobic and inhabit in surface and sub-surface environments, generated the biogenic Mn precipitates which have several unique properties, such as selectivity for competitive sorption, redox reaction on the surface, vacant sites for sorption. These properties provide engineering and environmental application to recover and remove heavy metals in aqueous environments.
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