• 한국표면공학회지
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• 제19권4호
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• pp.133-139
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• 1986

The effects of alternating voltage, $Cl^-$ ion and pH on the corrosion of Zn and Zn-Fe alloys have been investigated by using electrochemical techniques in $Ca(OH)_2$ solutions. The passive film $Zn(OH)_2$ was initially formed on the Zn surface and gradually transformed to $Ca(Zn(OH)_3)_2{\cdot}2H_2O$, which was identified with the X-ray diffraction method, SEM micrograph and EPMA. The passivity current increased with increasing alternating voltage and decrease AC frequency. ${\xi}$ phase in Zn-Fe alloys reduced the effects of AC. The effect of $Cl^-$ ion on the passivity current of Zn was similar to the AC effect, resulting in pits on Zn. It was also found that the passive region of Zn decreased rapidly below pH 10.3 of the solution.

• Bulletin of the Korean Chemical Society
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• 제21권4호
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• pp.393-400
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• 2000

2,2￠-Dihydroxyazobenzene (DHAB) was attached to poly(ethylenimine) (PEI) to obtain DHAB-PEI. Spectral titration revealed that uranyl, Fe(III), Cu(II), and Zn(II) ion form 1 : 1-type complexes with DHAB attached to PEI. Formation constants for the metal complexes formed by the DHAB moieties of DHAB-PEI were mea-sured by using various competing ligands. The results indicated thatthe concentrations of uranyl, Fe(III), and Cu(II) ions can be reduced to 10 -16 -10 -23 M at p 8 with DHAB-PEI when the concentration of the DHAB moiety is 1 residue M. By using cyanuric chloride as the coupling reagent, DHAB-PEI was immobilized on Sephadex G-25 resin to obtain DHAB-PEI-Seph. Binding of uranyl,Fe(III), Cu(II), and Zn(II) ion by DHAB-PEI-Seph was characterized by using competing ligands. A new method has been developed for characteriza-tion of metal sequestering ability of a chelating resin. Formation constants and metal-binding capacity of two sets of binding sites on the resin were estimated for each metal ion. DHAB-PI-Seph was applied to recovery of metals such as uranium,Fe, Cu, Zn, Pb, V, Mn, and W from seawater. The uranium recovery from seawaterby DHAB-PEI-Seph does not meet the criterion for economical feasibility partlydue to interference by Fe and Zn ions. The seawater used in the experiment was contaminated by Fe and Zn and, therefore, the efficiency of uranium extractionfrom seawater with DHAB-PEI-Seph could be improved if the experiment is carried out in a cleaner sea.

• 한국세라믹학회지
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• 제28권11호
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• pp.897-907
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• 1991

This study was conducted to research the formation and the color development of CoO-ZnO-Fe2O3-TiO2-SnO2 system for the purpose of synthesizing the spinel pigments which are stable at high temperature. After preparing CoO-ZnO-Fe2O3, in which CoO causes the color, as a basic composition, $\chi$CoO.(1-$\chi$)ZnO.Fe2O3 system, $\chi$CoO.(1-$\chi$)ZnO.TiO2 system and $\chi$CoO.(1-$\chi$)ZnO.SnO2 system were prepared with $\chi$=0, 0.2, 0.5, 0.7, 1.0 mole ratio respectively. The manufacturing was carried out at 128$0^{\circ}C$ for 90 minutes. These specimens were analyzed by the reflectance measurement and the X-ray diffraction analysis and the results were summarized as follows: 1. All of the specimens formed the spinel structure and were colored with stable yellow or blue. 2. As the content of CoO and Fe2O3 in the specimens being increased, the reflectance of each specimen was measured becoming lower and the colors were changed from yellow to greyish blue and from blue to dark blue. 3. As the substituting amount of Co2+ ion for Zn2+ ion in $\chi$CoO-ZnO-TiO2-SnO2 system being increased, the colors were changed from blue to greyish blue. The colors were changed from yellow to grayish green owing to the tetrahedral Co2+ ions being increased, the octahedral Co2+ ions being decreased with increasing the amount of Sn4+ ions. 4. CoO-ZnO-Fe2O3-TiO2-SnO2 system, in which Zn2+ was substituted with Co2+ and Fe3+ was substituted with Ti4+ and Sn4+, easily formed the spinel structure without regard to the amount of substitution or the ion owing to the selectivity of the coordination number: 4 of Zn2+, 4 of Co2+, 6 of Fe3+ or 6 of Ti4+ and Sn4+.

• 한국균학회지
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• 제19권3호
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• pp.220-225
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• 1991

1. 표고버섯 중 정제된 ATPase는 $Fe^{3+},\;Fe^{2+},\;Cd^{2+},\;Mg^{2+},\;K^{+}$ 및 $Co^{2+}$ 이온에 의하여 활성화 되었으나 $Zn^{2+},\;Ca^{2+},\;Cu^{2+}$ 및 $Ni^{2+}$ 이온에 의하여는 그 활성도가 억제되었다. 2. 5 mM $Fe^{3+}$, 10 mM $Fe^{2+}$, 1 mM $Cd^{2+}$, 5 mM $Mg^{2+}$, 5 mM $K^{+}$ 및 5 mM $Co^{2+}$이온은 이효소의 활성을 각각 130, 65, 65, 68, 105 및 23% 증가시켰다. 3.10 mM $Zn^{2+}$, 10 mM $Ca^{2+}$, 0.5 mM $Cu^{2+}$ 그리고 10 mM $Ni^{2+}$ 이온은 이효소의 활성을 각각 18, 19, 27% 그리고 30%의 억제효과를 보였다. 4. 10 mM ${Co_3}^{2-}$, 20 mM $CN^{-}$, 20 mM ${CH_3COO}^{-}$ 그리고 20 mM ${NO_3}^{-}$의 음이온은 이효소의 활성을각각 98, 95, 70% 그리고 50%를 억제시켰으나,${SO_4}^{2-}$ 이온은 농도증가에 따라 활성화 되었고, 20 mM 용액에서 21%로 활성도 증가의 최대치를 보였다.

• 한국균학회지
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• 제21권1호
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• pp.23-27
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• 1993

Rhizopus nigricans에 의한 progesterone의 $11{\alpha}-hydroxylation$과 ${5\alpha}-reduction$반응에 미치는 이온의 효과를 조사하였다. $Cu^{2+},\;Cd^{2+},\;Co^{2+},\;Mn^{2+},\;Zn^{2+},\;Fe^{2+},\;Mg^{2+},\;Fe^{3+}$ 및 $Na^+$은 $11{\alpha}-hydroxylation$ 반응의 활성을 저하시켰으나 $K^+$은 이 반응을 촉진시켰다. $11{\alpha}-hydroxyprogesterone$을 $5{\alpha}-reduction$시키는 효소는 $Fe^{2+},\;Mn^{2+},\;Mg^{2+},\;Co^{2+},\;Zn^{2+},\;Fe^{2+},\;K^+,\;Na^+$에 의하여 그 활성이 증가되었고 $Cd^{2+}$과 $Cu^{2+}$은 이 반응을 억제하였다. $11{\alpha}-hydroxylation$ 반응을 촉진하는데는 $10^{-3}\;M$의 $K^+$이 효과적이었으며 $5{\alpha}-reduction$반응을 엑제하기 위하여는 $10^{-4}\;M$의 $Cd^{2+}$이 적합하였다. R. nigricans는 세포내의 다효소체계에 의하여 progesterone이 $11\{alpha}-hydroxyprogesterone$으로 전환된 후 $11{\alpha}-hydroxy-allopregnane-3, 20-dione으로 $5{\alpha}-reduction$되므로 $10^{-3}\;M$의 $K^+$을 먼저 첨가하여 2시간 동안 progesterone 전환 반응을 실시한 후에 $10^{-4}\;M$의 $Cd^{2+}$을 첨가하였을 때 가장 높은 $11\{alpha}-hydroxyprogesterone$의 수득률을 얻을 수 있었다.

• 한국자기학회지
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• 제6권2호
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• pp.73-79
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• 1996

Y형 육방정 산화철$(Ba_{2}Me_{2}Fe_{12}O_{22}:Me=천이금속)$은 천이 금속으로 Co와 Zn가 포함된 경우 양호한 고주파 특성을 보이는 것으로 알려져 있다. 따라서, 결정 구조 내에 이들의 분포 상태를 파악하는 것이 중요하다. 본 논문에서는 엄밀한 성분 분석, X-선 회절 분석, 자기 특성 분석을 통하여 확인된 $Co_{2}Y$와 $Co_{1.6}Zn_{0.4}Y$시료에 대한 $M\"{o}ssbauer$ 분광 분석 결과로부터 다음과 같은 결론을 제시하였다. (1) Co는 주로 육방정 산화철의 S-block에 위치한 4배위 자리 $(6c_{IV})$와 S-, T-block 경계의 6배위자리(18h VI)에 들어간다. (2) Co의 일부를 Zn으로 치환하여도, Fe의 분포에는 큰 영향을 미치지 않는다.

• 한국환경과학회지
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• 제9권4호
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• pp.325-330
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• 2000

The hydroxyapatite (HAp) for the present study was prepared by precipitation method in semiconductor fabrication and the crystallized at ambient to 95$0^{\circ}C$ for 30min in electric furnace. The ion-exchange characteristics of HAp for various heavy metal ions such as $Cd^{2+}, Cu^{2+}, Mn^{2+}, Zn^{2+}, Fe^{2+}, Pb^{2+}, Al^{3+}, and Cr^{6+}$ in aqueous solution has been investigated. The removal ratio of various metal ions for HAp were investigated with regard to reaction time, concentration of standard solution, amount of HAp and pH of solution. The order of the ions exchanged amount was as follws: $Pb^{2+}, Fe^{3+}>Cu^{2+}>Zn^{2+}>Al^{3+}>Cd^{2+}>Mn^{2+}>Cr^{6+}. The Pb^{2+}$ ion was readily removed by the Hap, even in the strongly acidic region. The maximum amount of the ion-exchange equilibrium for $Pb^{2+}$ ion was about 45 mg/gram of HAp. The HAp would seem to be possible agent for the removal of heavy metal ions in waste water by recycling of waste sludge in semiconductor fabrication.

• Corrosion Science and Technology
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• 제5권2호
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• pp.39-44
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• 2006

The dissolution amount of Zn plate was $0.058mg/cm^2$ in the non-magnetically treated solution, and was $0.059mg/cm^2$ in the magnetically treated solution after 24 hours of immersion. The magnetic treatment had no effect to corrosion of Zn plate as pH on surface was not recognized the difference. The addition of Zn(II) ion in the solution was prepared to the effects of corrosion and dissolution of Fe. The regularity was not obtained the effect of the magnetic treatment on the dissolution of Fe plate.

• 한국수처리학회지
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• 제26권6호
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• pp.13-26
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• 2018

This research was conducted to elucidate the removal mechanism of heavy metals and sulfate ion from acid mine drainage(AMD) by porous zeolite-slag ceramics (ZS ceramics) packed in a column reactor system. The average removal efficiencies of heavy metals and sulfate ion from AMD by the 1:3(Z:S) porous ZS ceramics in the column reactor under the HRT condition of 24 hours were Al 97.5%, As 98.8%, Cd 86.1%, Cu 96.2%, Fe 99.7%, Mn 64.1%, Pb 97.2%, Zn 66.7%, and $SO_4{^{2-}}$ 76.0% during 121 days of operation time. The XRD analysis showed that the ferric iron from AMD could be removed by adsorption and/or ion-exchange on the porous ZS ceramics. In addition it was known that Al, As, Cu, Mn, and Zn could adsorb or coprecipitate on the surface of Fe precipitates such as schwertmannite, ferrihydrite, or goethite. The EDS analysis revealed that Al, Fe, and Mn, which were of relatively high concentration in the AMD, would be adsorbed and/or ion-exchanged on the porous ZS ceramics and also exhibited that Al, Cu, Fe, Mn, and Zn could be precipitated as the form of metal hydroxide or sulfate and adsorbed or coprecipitated on the surface of Fe precipitates. The microscopic results on the porous ZS ceramics and precipitated sludge in a column reactor system suggested that the heavy metals and sulfate ion from AMD would be eliminated by the multiple mechanisms of coprecipitation, adsorption, ion-exchange as well as precipitation.

• 한국균학회지
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• 제28권1호
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• pp.60-65
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• 2000

할미송이버섯으로부터 3단계를 거처 분자량이 각각 18 kDa(FE-1)과 18.2 kDa(FE-2)인 두 개의 혈전용해효소를 분리 정제하였다. 이 효소들은 지금까지 알려진 혈전용해 효소의 질량에 비해 비교적 작았고 두 효소(FE-1과 FE-2)의 15번째까지의 N-terminal amino acid서열은 A-L-Y-V-G-X-S-P-X-Q-Q-S-L-L-V로 같았다. FE-1은 ICP-MS의 결과 $Zn^{2+}$을 mole당 0.98 mole 포함하고 있는 metalloprotease로 pH 7.5와 $55^{\circ}C$에서 가장 큰 활성을 나타내고, 1,10-phenanthroline의 첨가 시 저하된 활성은 $Zn^{2+}$나 $Co^{2+}$의 첨가에 의해 재생되었다.