2003 Fiscal Year Final Research Report Summary
Development of in-situ remediation of contaminated soil by electrochemical method
| Project/Area Number |
13480177
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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 |
環境保全
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| Research Institution | Osaka University |
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Principal Investigator |
HIRATA Yushi Osaka University, Graduate School of Engineering Science, Professor, 大学院基礎工学研究科, 教授 (90029512)
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| Co-Investigator(Kenkyū-buntansha) |
SHIBA Sadataka Osaka University, Graduate School of Engineering Science, Research Associate, 大学院基礎工学研究科, 助手 (40026274)
YAMABERI Keiko Osaka University, Graduate School of Engineering Science, Research Associate, 大学院基礎工学研究科, 助手 (70273612)
SENO Tadachika Shizuoka University, Graduate School of Science and Engineering, Associate Professor, 大学院理工学研究科, 助教授 (60135241)
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| Project Period (FY) |
2001 – 2004
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| Keywords | Contaminated soil / in-situ remediation / decontamination / heavy metal ion / clay mineral / groundwater / electroosmotic flow / adsorption / desorption |
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| Research Abstract |
In in-situ process for remediation of contaminated soil in this project, the process fluid is supplied through the pore space in the soil by utilizing an electroosmotic flow, which can be generated by applying an electric field to the soil. The contaminants are removed by promoting the ion-exchange/complex formation reactions between the bulk liquid and the soil surface, and then the aquifer or groundwater containing desorption contaminants is transported to an electrode well, where the contaminants are removed by the conventional separation method. The key technologies required for developing this remediation process are the desorption of contaminants from the soil by the ion-exchange/complex formation reactions and the transport of aquifer containing them by electroosmosis. The research of this project was conducted by focusing on these fundamental subjects.
In order to make a rational assessment on the applicability of this technique to a real remediation, the soil must be sampled an
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d analyzed to estimate the electroosmotic flow rate and the degree of desorption of contaminants from the soil. We developed a method to measure the electroosmotic flow rate based on the analytical solution of a capillary flow associated with pressure and electric forces. We applied this method to steady and unsteady measurements of electroosmotic flow generated in a silica capillary and a column bed packed with silica particles. The results to be stressed are as follows; little effect of neutral process fluids for remediation, availability of complex reagents for desorption of contaminants, and requirement of longer process time for desorption of metal ions with larger valences.
Using kaolinate with aluminol and silanol functional groups as mock soil, its surface charge was determined by acid/base titration. In addition, we tried to estimate the surface potential by applying an approximate solution of the Poisson-Boltzmann equation. From a comparison of the estimated surface potential with the measured zeta potential, it was concluded that the estimation method of the surface potential was not available due to the constraints for the solution. As a consequence, we took account of the time variation of the electric double layer due to the desorption of contaminants as a delay effect in an adsorption/desorption reaction model, which was incorporated into the simulation. Simulated results suggest that the electrochemical remediation is effective particularly for the contaminated soil near the anode and that simultaneous use of flow forced by pumps is additional effect for improving the remediation. Less
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Research Products
(10 results)
