1989 Fiscal Year Final Research Report Summary
Absorption of Hydrogen Sulfide into Aqueous Ferric Sulfate Solutions in the Presence of Iron-Oxidizing Bacteria
| Project/Area Number |
63550714
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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 |
化学工学
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| Research Institution | University of Osaka Prefecture |
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Principal Investigator |
HATANAKA Junichi Univ. of Osaka Pref., Col. of Eng., Assistant Professor, 工学部, 講師 (60081361)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Hidemi Univ. of Osaka Pref., Col. of Eng., Research Associate, 工学部, 助手 (70198232)
KONISHI Yasuhiro Univ. of Osaka Pref., Col. of Eng., Research Associate, 工学部, 助手 (90167403)
ASAI Satoru Univ. of Osaka Pref., Col. of Eng., Professor, 工学部, 教授 (90081348)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Iron-oxidizing bacteria / Ferric sulfate solution / Hydrogen sulfide / Gas absorption / Activated carbon / Adsorption |
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| Research Abstract |
1. Absorption of H_2S into aqueous Fe_2(SP_4)_3 solutions was found to be accompanied by an irreversible reaction between dissolved H_2S and reactant FeOH^<2+> 1ions, which is first order with respect to the individual species. The relevant reaction rate constants were correlated a function of temperature, independently of the ionic strength of the solution.
2. Cells of the iron-oxidizing bacterium, Thiobacillus ferrooxidans were immobilized on fine panicles of activated carbon by adsorption. The experimental results for the bacterial adsorption equilibrium were correlated by the henry adsorption isotherm, and Henry's constant decreased with an increase in the particle size.
3. The rates of the liquid-phase oxidation of Fe^<2+> ions by T. ferrooxidans (regeneration of Fe_2(SO_4)_3) were measured by varying the activated carbon - liquid loading ratio, the particle size and the initial concentration of Fe^<2+> ions. The kinetic data were analyzed to evaluate the growth yield Y_A and the specific growth rate mu_A of adsorbed bacteria. The evaluated value of Y_A was independent of the operating variables and compared favorably with the growth yield of free cells in the liquid phase. A expression for the evaluated mu_A value was obtained as a function of the operating variables. The maximum value of mu_A was about 6 times as high as the maximum specific growth rate of the free cells.
4. The effect of fine particles on the absorption rate of H_2S into aqueous Fe_2(SO_4)_3 solutions in the absence of the bacteria were studied with an agitated vessel with a flat interface. The measured absorption rates were increased up to 2 times due to the presence of fine particles of activated carbon.
With the above research data in mind, further work is under way to clarify the mechanism of absorption of H_2S into aqueous Fe_2(SO_4)_3 solutions in the presence of T. ferrooxidans immobilized on the activated carbon, which is the ultimate object of this research.
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