| Project/Area Number |
13555281
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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 | 展開研究 |
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| Research Field |
資源開発工学
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
KONISHI Yasuhito Osaka Prefecture University, Graduate School, Professor, 工学研究科, 教授 (90167403)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAHARA Keisuke JFE Engineering Corporation, Aqua Technology Research Dept., Director General, エンジニアリング研究所, 研究部長
NOMURA Toshiyuki Osaka Prefecture University, Graduate School, Research Associate, 工学研究科, 助手 (00285305)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥13,500,000 (Direct Cost: ¥13,500,000)
Fiscal Year 2003: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2002: ¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 2001: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | Fly ash / Heavy metals / Sulfur cycle / Zinc recovery / Bioleaching / Sulfur-oxidizing bacteria / Sulfate-reducing bacteria / Phototrophic bacteria / 物質循環 / 環境修復 / 亜鉛 / ゴミ焼却 |
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| Research Abstract |
There have been many investigations into the recovery of valuable metals in fly ash from municipal waste incineration. Although chemical processes have been extensively developed for extracting the metals from fly ash, another possible process is the treatment of fly ash by microbial means.
In this report we describe a microbial recovery of zinc in fly ash, in which the sulfur cycle (elemental sulfur (S^0) → sulfate (SO_4^<2-> → hydrogen sulfide (H_2S) → elemental sulfur) is artificially constructed using several microorganisms, and the microbial sulfur transformations are utilized for the recovery of zinc. First, the zinc in the fly ash was solubilized during the growth of thermophilic sulfur-oxidizing microbe Acidianus brierleyi on S^0. In this bioleaching process, sulfuric acid was biologically produced from 50 added to liquid medium and was simultaneously used to leach zinc from the fly ash. Second, sulfate ions accumulated in the leach solution were reduced to H_2S using the sulfate-reducing bacteria, and the biogenic H_2S could be used to recover dissolved zinc as sulfide precipitates. Finally, the effluent H_2S from the zinc recovery operation was oxidized to S^0 using photosynthetic bacteria, and the precipitated S^0 could be recycled to the bioleaching process. Batch tests were, conducted to collect rate data and optimize various process parameters for the individual bioprocesses such as the bioleaching of fly ash, the bioconversion of SO_4^<2-> to H_2S, and the microbial oxidation of biogenic H_2S to S^0. The rate data indicated that the bioleaching process is a rate-determining step. Under the conditions determined as optimum, the bioleaching of zinc from fly ash yielded 90 % extraction of zinc in 9 days of batch operation.
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