1993 Fiscal Year Final Research Report Summary
Study of Effect of Freezing-Thawing Process on the Mechanizm of Acid Rain Generation
| Project/Area Number |
04804047
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
分析・地球化学
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| Research Institution | University of Osaka Prefecture |
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Principal Investigator |
MAEDA Yasuaki University of Osaka Prefecture, College of Engineering, Professor, 工学部, 教授 (80081438)
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| Co-Investigator(Kenkyū-buntansha) |
TAKENAKA Norimichi University of Osaka Prefecture, College of Engineering, Associate Reseacher, 工学部, 助手 (70236488)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Acid rain / Nitrite / Freezing / Ion separation / Redox reaction / Boundary layr |
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| Research Abstract |
The reaction of nitrite with dissolved oxygen had been found to be abonormally accelerated by freezing of aqueous solution. Then the mechanizm of acceleration effect of freezing was studied.and the role of freezing process on the reaction in environment was investigated. The acceleration effect is most likly due to the follwing mechanizm. Reactants were excluded from growing ice crystals to solution. The extents of exclusion of each reactant were difference. The unbalance of the exclusion of cations and anions causes the potential difference between ice and solution. The positively charged ice attracts anions (nitrite). Nitrite and oxygen are concentrated at the interface of ice and solution with growing ice. The reaction is accelerated by very high concentrated reactants.
The acceleration of the reaction to from nitrate was also observed. However the concentrations of nitrite in rain are very low, and it is found that the pH of rain was not affected by freezing. The high concentration of nitrite in fog (>0.1mmol/L) was obtained at Mt.Ikoma.In this case the pH was depressed more Than 0.1. Since the freezing process is not an abnormal process in environment, it is considered that the acceleration by freezing plays an important role in environment.
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