| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2014: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2013: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2012: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
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| Outline of Final Research Achievements |
Humic substances (HSs) are heterogeneous mixture of high-molecular-weight organic materials formed by humification of animals, plants and microbes. HSs plays an important role in the transportation of cations in environment, and are confirmed to be present even in the deep underground where radioactive wastes are planned to be disposed. The purpose of this study is accurate determination of delta_G, _H,_S in protonation and complexation of natural humic acid with Cu(II) by calorimetric titration. Furthermore, the reaction mechanism is discussed from the obtained thermodynamic quantities. It is revealed that the absolute value of complexation enthalpy is negative and decreases with pH increase. In addition, the complexation reaction of Elliot Soil humic acid is driven by enthalpy term, while the protonation reaction in this pH range is driven by entropy term. This difference is considered to be caused by the difference of the bonding mode between proton and Cu(II) to humic acid.
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