• 한국표면공학회지
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• 제15권4호
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• pp.218-225
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• 1982

The effects of ferrous ion on the properties of bright nickel electrodeposit were exa-mined. Iron exists as ferrous ion (Fe+2) and ferric ion (Fe+3) in the bath, a portion of the former tend to be oxidized to the somewhat harmful ferric ion. Iron was added to bath as the ferrous sulfate, ferrous ion prevented from the oxidation with citric acid. It was found that the hardness was increased as the concentration of ferrous ion, the ductility was slightly increased too. The appearance can obtain the wide bright deposits within 4g/$\ell$. The corrosion resistance drastically dropped from 5g/$\ell$ In the case of considering the effect of ferrous ion on the corrosion resistance and the appearance, the allowable limits is 4g/$\ell$, if the reductant is used.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 가을 학술발표회 발표논문집
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• pp.319-321
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• 2003

This research was carried out to evaluate the removal efficiencies of CODcr and colour for the dyeing wastewater by ferrous solution in Fenton process. The results showed that COD was mainly removed by Fenton coagulation, where the ferric ions are formed in the initial step of Fenton reaction. On the other hand colour was removed by Fenton oxidation rather than Fenton coagulation. The removal mechanism of CODcr and colour was mainly coagulation by ferrous ion, ferric ion and Fenton oxidation. The removal efficiencies were dependent on the ferric ion amount at the beginning of the reaction. However the final removal efficiency of COD and colour was in the order of Fenton oxidation, ferric ion coagulation and ferrous ion coagulation. The reason of the highest removal efficiency by Fenton oxidation can be explained by the chain reactions with ferrous solution, ferric ion and hydrogen peroxide.

• 한국환경과학회지
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• 제13권11호
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• pp.987-991
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• 2004

The purpose of this research is to evaluate the removal efficiencies of COD$\_$Cr/ and color for the dyeing wastewater by the different dosages of ferrous solution and H$_2$O$_2$ in Fenton process. In the case of H$_2$O$_2$ divided dosage for the Fenton's reagent 7:3 of H$_2$O$_2$ was more effective than 3:7 to remove COD$\_$Cr/ and color. The results showed that COD$\_$Cr/ was mainly removed by Fenton coagulation, where the ferric ions are formed in the initial step of Fenton reaction. On the other hand color was removed by Fenton oxidation rather than Fenton coagulation. The removal mechanism of COD$\_$Cr/ and color was mainly coagulation by ferrous ion, ferric ion and Fenton oxidation. The removal efficiencies were dependent on the ferric ion amount at the beginning of the reaction. However, the final removal efficiency of COD$\_$Cr/ and color was in the order of Fenton oxidation, ferric ion coagulation and ferrous ion coagulation. The reason of the highest removal efficiency by Fenton oxidation can be explained by the chain reactions with ferrous solution, ferric ion and hydrogen peroxide.

• 한국식품영양학회지
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• 제35권5호
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• pp.313-323
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• 2022

To investigate antioxidant effects of tea tree root extracts using various extraction methods, cytotoxicity, DPPH and ABTS radical scavenging, SOD, nitrite scavenging activity and inhibitory activity of lipid peroxidation, reducing power, ferrous ion chelating activity were measured. Cytotoxicity for RAW 264.7 cells was not observed at concentrations treated with below 90 ㎍/mL in all extracts. The maximum DPPH radical, nitrite scavenging, SOD activity and inhibitory activity of lipid peroxidation were obtained at the ethylacetate and 70% ethanol extract. The maximum ABTS radical scavenging activity was obtained at the ethylacetate and hot water extract. However, in the case of reducing power and ferrous ion chelating activity, they were obtained at 70% ethanol and hexane extract, respectively. Nitrate scavenging activity showed the most excellent scavenging ability of 59.6% at 90 ㎍/mL of ethylacetate. The hexane extract had the highest ferrous ion chelating activity, showing 61.05% at 50 ㎍/mL, 66.07% at 70 ㎍/mL and 76.81% at 90 ㎍/mL, respectively. The results of this research show that the ethylacetate and 70% ethanol extracts of tea tree root can be used as a natural material for scavenging the radicals. However, future study is necessary to understand the mechanism of antioxidant activity by identification of substances.

• 한국재료학회지
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• 제20권6호
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• pp.301-306
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• 2010

The chemical formula of magnetite ($Fe_3O_4$) is $FeO{\cdot}Fe_2O_3$, t magnetite being composed of divalent ferrous ion and trivalent ferric ion. In this study, the influence of the coexistence of ferrous and ferric ion on the formation of iron oxide was investigated. The effect of the co-precipitation parameters (equivalent ratio and reaction temperature) on the formation of iron oxide was investigated using ferric sulfate, ferrous sulfate and ammonia. The equivalent ratio was varied from 0.1 to 3.0 and the reaction temperature was varied from 25 to 75. The concentration of the three starting solutions was 0.01mole. Jarosite was formed when equivalent ratios were 0.1-0.25 and jarosite, goethite, magnetite were formed when equivalent ratios were 0.25-0.6. Single-phase magnetite was formed when the equivalent ratio was above 0.65. The crystallite size and median particle size of the magnetite decreased when the equivalent ratio was increased from 0.65 to 3.0. However, the crystallite size and median particle size of the magnetite increased when the reaction temperature was increased from $25^{\circ}C$ to $75^{\circ}C$. When ferric and ferrous sulfates were used together, the synthetic conditions to get single phase magnetite became simpler than when ferrous sulfate was used alone because of the co-existence of $Fe^{2+}$ and $Fe^{3+}$ in the solution.

• 한국자원식물학회지
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• 제23권2호
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• pp.123-130
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• 2010

본 연구는 식용 및 약용으로 사용되는 울릉미역취와 톱풀 어린잎의 항산화활성 및 생리활성에 미치는 가압열처리의 영향을 알아보기 위하여 시행하였다. 4월 초순에 충북청원군 노지에서 어린잎을 채취한 직후 가압열처리($121^{\circ}C$, 1.2기압, 15분) 또는 무처리하여 동결건조한 후 분쇄하여 80% 에탄올 용매로 환류냉각추출한 추출물의 총 폴리페놀 및 플라보노이드의 함량, DPPH와 ABTS radical 소거능 및 ferrou ion chelating 정도를 측정 하였다. 톱풀과 울릉미역취의 추출수율은 가압열처리한 울릉미역취에서 가장 높았고(39.55%), 가압열처리한 톱풀 어린잎에서 가장 낮았다(28.15%). 톱풀과 울릉미역취 어린잎은 가압열처리 후 DPPH radical 소거활성이 현저히 감소하여, 각각 $1.506\;mg{\cdot}mL^{-1}$, $0.669\;mg{\cdot}mL^{-1}$씩 $RC_{50}$값이 증가하였다. ABTS radical 소거활성 또한 각각 $0.704\;mg{\cdot}mL^{-1}$, $0.421\;mg{\cdot}mL^{-1}$ 씩 $RC_{50}$값이 증가하였다. 반면 ferrous ion chelate 효과는 가압열처리에 의하여 향상되었으며, 톱풀의 어린잎에서 큰 폭으로 상승하였다. 또한 가압열처리는 총 폴리페놀과 플라보노이드 함량을 감소시켰는데, 특히 톱풀 어린잎에서 감소폭이 컸다. 따라서 본 실험에서는 가압열처리는 울릉미 역취와 톱풀 어린잎의 Ferrous ion clelate 효과를 향상시킬 수 있지만, DPPH 및 ABTS radical 소거능과 총 폴리페놀 및 플라보노이드의 함량을 감소시키는 것으로 나타났다. 또한, 톱풀의 어린잎은 울릉미역취에 비하여 열안정성이 낮아 열처리에 의한 활성의 변화가 큰 것으로 나타났다.

• 한국진공학회지
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• 제4권S2호
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• pp.106-114
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• 1995

Direct implantation of metallic ion species has been employed in surface processing of industrial components and tools with very encouraging improvements in recent years. In spite of high technicla effectiveness, this new surface processing technique has not been extensively accepted by industries mainly because of high cost(capital and operating) compared with other competitive surface processing techniques. High current and large implantation area with eliminating the mass analyzer and the beam-scanning unit make metal vapor vacuum are(MEVVA)source ion implantation versatile, simple and cheap to operate and well suited to commercial surface processing. In this paper, the recent development of MEVVA source ion implantation technique ar Beijing Normal University has been reviewed and the results of production trials of several industrial components and tools implanted by MEVVA source ion implantation have been presented and discussed.

• Journal of Microbiology and Biotechnology
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• 제10권1호
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• pp.35-42
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• 2000

Reaction characteristics of 4-methylcatechol 2,3-dioxygenase (4MC230) purified from Pseudomonas putida SU10 with a higher activity toward 4-methylcatechol than catechol or 3-cethylcatechol were studied by altering their physical and chemical properties. The enzyme exhibited a maximum activity at pH 7.5 and approximately 40% at pH 6.0 for 4-methylcatechol hydrolysis. The optimum temperature for the enzyme was around $35^{\circ}C$, since the enzyme was unstable at higher temperature. Acetone(10%) stabilized the 4MC230. The effects of solvent and other chemicals (inactivator or reactivator) for the reactivation of the 4MC230 were also investigated. Silver nitrate and hydrogen peroxid severely deactivated the enzyme and the deactivation by hydrogen peroxide severely deactivated the enzyme and the deactivation by hydrogen peroxide was mainly due to the oxidation of ferrous ion to ferric ion. Some solvents acted as an activator and protector for the enzyme from deactivation by hydrogen peroxide. Ascorbate, cysteine, or ferrous ion reactivated the deactivated enzyme by hydrogen peroxide. The addition of ferrous ion together with a reducing agent fully recovered the enzyme activity and increased its activity abut 2 times.

• 한국균학회지
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• 제21권3호
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• pp.157-164
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• 1993

1. 표고버섯중 광감응성 mitochondrial $F_1-ATPase$는 $Fe^{3+},\;Fe^{2-}$ 및 $Mg^{2+}$ 이온에 의하여 각각 활성화 되었으나 5.0 mM $Fe^{3+}$ 이온에 의한 상대활성도는 대조구에 비하여 107% 증가시켰다. 2 $Mg^{2+}$ 존재하에서 $Fe^{3+}$ 및 $Fe^{2-}$ 각 이온 농도효과는 모두 효소의 활성을 증가시켰으나 0.1 mM $Mg^{2+}$과 5.0 mM $Fe^{3+}$ 이온의 공존하에서 170%를 증가시켜 $Mg^{2+}$ 이온에 의한 상승작용을 보였다. 3. 0.1 mM $Mg^{2+}$와 0.1 mM $Fe^{2+}$ 존재하에서 $Fe^{3+}$ 이온농도효과는 그 농도가 5.0 mM일 때 168%의 활성도 증가를 보여 $Fe^{2-}$ 이온공존효과는 없었다. 4. 이 효소는 $Mg^{2+}$ 및 $Fe^{3+}$ 이온에 의하여 활성화되는 특성을 가지고 있으며 활성금속이온 존재하에서 측정한 최적 pH 빛 온도는 각각 7.5 및 $66^{\circ}C$였다.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2577-2583
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• 2009

Presented are the formation of iron oxide layers on evaporator tubes in an actual fossil power plant operated under all volatile treatment (AVT) condition and an experimental simulation of iron oxide formation in the presence of ferrous and ferric ions. After actual operations for 12781 and 36326 hr in the power plant, two iron oxide layers of magnetite on the evaporator tubes were found: a continuous inner layer and a porous outer layer. The experimental simulation (i.e., artificial corrosion in the presence of ferrous and ferric ions at 100 ppm level for 100 hr) reveals that ferrous ions turn the continuous inner oxide layer on tube metal to cracks and pores, while ferric ions facilitate the production of porous outer oxide layer consisting of large crystallites. Based on a comparison of the oxide layers produced in the experimental simulation with those observed on the actually used tubes, we propose possible routes for oxid layer formation schematically. In addition, the limits of the proposed corrosion routes are discussed in detail.