• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.280-283
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• 2005

한국원자력연구소 내 심부시추공(YS-01, 500m)에 설치된 다중패커시스템(multi-packer system)을 이용하여 양수(pumping) 시 GL. $-457.5{\sim}-500m$ 구간의 지하수에 대한 중요한 지화학 파라미터인 pH, 산화-환원전위, 용존산소 및 전기전도도 등을 장기간 측정하였다. 이에 따르면 현장측정자료는 시간이 경과함에 따라 변화되며 장시간이 경과된 후에 안정화됨을 보여주고 있다. 특히, 산화-환원전위의 경우는 10일이 경과되었음에도 계속 변화하고 있다. 심부지하수 뿐만 아니라 일반 지하수의 경우에도 이러한 파라미터 측정 시 안정화시간에 대하여 유의하여야 할 것이다.

• Journal of the Korean Chemical Society
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• v.11 no.4
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• pp.159-164
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• 1967

An exact expression of the titration fraction as a function of the potential is derived for the cases where the coefficients of the both half reactions involved in the titration are homogeneous. It shows that the potential is independent of the concentration of the reagents not only at the equivalence point but also at all titration fractions. The sharpness of the end point detection by potentiometric method is shown to depend not only on the difference of the normal potentials involved but also strongly on the number of electrons transferred in each half reaction. The inflexion point of the potentiometric titration curve is shown to be slightly off from the equivalence point, including the cases where the number of electrons involved are equal. Completeness of the reaction in the course of titration is analyzed, too, mostly in terms of equilibrium constant, thus most of the results are applicable to any type of equilibrium in a single phase with particular relationship of coefficients of chemical equation.

• Korean Journal of Environmental Agriculture
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• v.28 no.2
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• pp.165-170
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• 2009

The increase in P availability to rice under flooded soil conditions involves the reductive dissolution of iron phosphate and iron (hydr)oxide phosphate. However, since $NO_3^-$ is a more favourable electron acceptor in anaerobic soils than Fe, high$NO_3^-$ loads function as a redox buffer limiting the reduction of Fe. The effect of adding $NO_3^-$ on Fe reduction and P release in paddy soil was investigated. Pot experiment was conducted where $NO_3^-$ was added to flooded soil and changes of redox potential and $Fe_2^+$, $NO_3^-$ and $PO_4^{3-}$ concentrations in soil solution at 10 cm depth were monitored as a function of time. Redox potential decreased with time to -96 mV, but it was temporarily poised at about 330${\sim}$360 mV when $NO_3^-$ was present. Nitrate addition to soil led to reduced release of $Fe_2^+$ and prevented the solubilization of P. Phosphate in pore water began to rise soon after incubation and reached final concentrations about 0.82 mg P/L in the soil without $NO_3^-$ addition. But, in the soil with $NO_3^-$ addition, $PO_4^{3-}$ in pore water was maintained in the range of 0.2${\sim}$0.3 mg P/L. The duration of inhibition in $Fe_2^+$ release was closely related to the presence of $NO_3^-$, and the timing of $PO_4^{3-}$ release was inversely related to the $NO_3^-$ concentration in soil solution. The results suggest that preferential use of $NO_3^-$ as an electron acceptor in anaerobic soil condition can strongly limit Fe reduction and P solubilization.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.276-280
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• 2017

In this study, we investigated the effect of sterilization and the neutralization of treated ballast water using seawater electrolysis. The electrolysis apparatus has a cation-selective membrane for passing the cation and a titanium electrode in each cell. We examined the sterilization effect after an incubation period of 24 hr. The oxidation reaction during electrolysis caused, the solution to become strongly acidic due to the generation of a hydroxyl group, and the oxidation reduction potentials(ORP) was increased to 800 - 1200mV. After the reduction reaction, the solution became alkaline(pH 9 - 12), and ORP was decreased to - 900 - - 750 mV. It might be possible to control the pH of ballast water through electrolysis. In addition, we demonstrated the effects of sterilization of ballast water containing generated hypochlorous acid using electrolysis under high ORP condition.

• Bulletin of Korea Environmental Preservation Association
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• v.15 no.2
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• pp.17-23
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• 1993

• Geotechnical Engineering
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• v.22 no.1
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• pp.46-53
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• 2006

• 수도
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• s.32
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• pp.15-38
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• 1984

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.4
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• pp.79-84
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• 2005

This paper proposes the new type of an ion exchange water generator system. The system has an +/- ion exchange membrane located in center and a diagonal-interdigit type electrode applied to a pulsed power. This system is studied in the liquid for the oxidation/reduction potential and the dissolved oxygen concentration by the polarity effects. Consequently, as a diagonal-interdigit type electrode is installed in each side of device, the oxidation/reduction potential and dissolved oxygen concentration by polarity changes and electrical resistivity differences be observed. An ion concentration in the ion exchange water generator system is increased by dissolved oxygen generated from oxidation/reduction potential changes.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.76-81
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• 1991

- The effect of redox potential (ORP) on lysine production by a leucine auxotrophic regulatory mutant of Corynebacterium glutclmicum on molasses medium was investigated in a 2-1 jar fermentor at pH 6.9 and $32^{\circ}C$. At a dilution rate of D=O.l $h ^1$, a maximum yield of Yr,,s=0.24 was obtained in either carbon- or leucine-limited chemostat where the redox potential was between -60 mV and - 100 mV. This level of redox potential corresponded to moderate oxygen deficiency. Under a high oxygen deficient condition of the redox potential of - 130 rnV (oxygen-limited chemostat), all the kinetic parameters such as $Y_[p/s}, q_s\; and \; q_p$ were decreased significantly and significant amounts of byproducts including glycine, alanine and valine were accumulated in the culture, indicating that the control of redox potential is important in lysine fermentation. At the redox potential of - 40 mV, on the other hand, large quantities of arginine (up to 0.38g/l) and glutamic acid (up to 0.12 g/l) were produced. A maximum lysine productivity of 2.41 g/l/h was achieved at - 66 mV under a carbon-limited condition.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.127-133
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• 2001

It can be known that from leachate generated in the initial stage of landfill there are a lot of undecomposed orgainc materials, its sulfur component reduces to sulfide ion by sulfur reducing microorgarnisms as an anaerobic digestion proceeds, the sulfide ion makes the leachate discolor to black by forming metal sulfide sol, on condition that much more equivalent of sulfide ion than that of metal ion is present, and the metal sulfide sol can be generated to the precipitates by forming black-colored particulates. Therefore, we can confirm the important possibility for the economic and efficient treatment of leachate that it can be passivated, provided that much more equivalent of sulfide ion is present in the reaction of sulfide ion and metal ion.