• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.107-110
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• 2003

Reduction of nitrate by zero valent iron (Fe$^{0}$ ) has been previously studied, but the proper treatment for the by-product of ammonium has not been reported. However, in terms of nitrogen contamination, ammonium may be regarded as another form of nitrogen contaminants since it can be oxidized to nitrate again under aerobic conditions. This study is focused on simultaneous removal of nitrate and its by-product of ammonium, with the ZanF (Zeolite anchored Fe), a product derived from zeolite modified by Fe(II) chloride followed by reduction with sodium borohydride. Batch experiments were performed without buffer at two different pH condition with ZanF, iron filing, Fe(II)-sorbed zeolite, and pure zeolite to estimate the nitrate reduction and the ammonium production. At higher pH, removal rate of nitrate was reduced in both ZanF and iron filings. ZnF removed 60 % of nitrate at initial pH of 3.3 with no production of ammonium, while iron filing showed equivalent production of ammonium to the reduced amount of nitrate. In terms of nitrogen contamination, ZanF removed about 60 % and 40 % at initial pH of 3.3 and 6, respectively, while iron filing presented negligible removal against total nitrogen including nitrate and ammonium.

• 한국토양비료학회지
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• 제28권3호
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• pp.287-294
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• 1995

본 논문에서는 철 이외에 사이데로포 생성에 관여하는 요인을 연구하였다. 약산성(pH6)에서 세포의 양은 감소하는 반면에 세포당 사이데로포의 생성은 증가하였다. 사이데로포 생성의 적정온도는 7NSK2 균주가 $12^{\circ}C$이고 ANP15은 $19^{\circ}C$였다. 배지의 C : N 비율에 따른 사이데로포 생성력을 보면 C : N율이 낮은 배지에서는 사이데로포 생성과 세포생장은 감소됐다. 서로 다른 배지에서 사이데로포 생성을 조사한 바에 의하면 citrate를 탄소원으로 했을 경우 세포의 철 흡수능력이 증가했으며 사이데로포 생성도 감소되었다. 그러나 Glucose나 Succiuate에 비해서 citrate 배치의 세포량에는 별 차이가 나타나지 않았다. 이상의 결과로 보아 환경요인으로 작용할 수 있는 pH나 온도, 탄소원 등은 철분 외에도 사이데로포의 생성에 영향을 미칠 수 있음을 확인하게 되었다.

• 한국미생물·생명공학회지
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• 제42권2호
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• pp.131-138
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• 2014

While coupling wastewater treatment with microalgal bioenergy production is very promising, new approaches are needed to enhance microalgal growth and lipid accumulation in wastewater. Therefore, this study investigated the effect of iron on the growth, nutrient removal, and lipid accumulation of Scenedesmus sp. LX1 in both artificial wastewater and domestic secondary effluents. When increasing the iron concentration from 0 to 2 mg/l in the artificial wastewater, the biomass production of Scenedesmus sp. LX1 increased from 0.17 to 0.54 g/l; the nitrogen and phosphorus removal efficiency increased from 15.7% and 80.6% to 97.0% and 99.2%, respectively; and the lipid content was enhanced 84.2%. The relationship between the carrying capacity/maximal population growth rate of Scenedesmus sp. LX1 and the initial iron concentration were also in accordance with the Monod model. Furthermore, when increasing the iron concentration to 2 mg/l in four different domestic secondary effluent samples, the lipid content and lipid production of Scenedesmus sp. LX1 was improved by 17.4-33.7% and 21.5-41.8%, respectively.

• Journal of Microbiology and Biotechnology
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• 제29권1호
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• pp.105-113
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• 2019

Although siderophore compounds are mainly biosynthesized as a response to iron deficiency in the environment, they also bind with other metals. A few studies have been conducted on the impact of heavy metals on the siderophore-mediated iron uptake by microbiome. Here, we investigated siderophore production by a variety of rhizosphere fungi under different concentrations of $Zn^{2+}$ ion. These strains were specifically isolated from the rhizosphere of Panax ginseng (Korean ginseng). The siderophore production of isolated fungi was investigated with chrome azurol S (CAS) assay liquid media amended with different concentrations of $Zn^{2+}$ (50 to $250{\mu}g/ml$). The percentage of siderophore units was quantified using the ultra-violet (UV) irradiation method. The results indicated that high concentrations of $Zn^{2+}$ ion increase the production of siderophore in iron-limited cultures. Maximum siderophore production by the fungal strains was detected at $Zn^{2+}$ ion concentration of $150{\mu}g/ml$ except for Mortierella sp., which had the highest siderophore production at $200{\mu}g/ml$. One potent siderophore-producing strain (Penicillium sp. JJHO) was strongly influenced by the presence of $Zn^{2+}$ ions and showed high identity to P. commune (100% using 18S-rRNA sequencing). The purified siderophores of the Penicillium sp. JJHO strain were chemically identified using UV, Fourier-transform infrared spectroscopy (FTIR), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF-MS) spectra.

• Applied Biological Chemistry
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• 제44권4호
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• pp.219-223
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• 2001

Hemoglobin(Hgb)의 효소 가수분해액으로부터 고농도 heme-iron의 분리에 영향을 주는 기질의 농도, 가수분해도 (DH, degree of hydrolysis) 및 분리 pH의 효과 등을 조사하였으며, pilot scale에서 고농도 heme-iron을 생산하였다. 최적 반응조건(pH 10.0, $50^{\circ}C$, 5 hr)에서의 Esperase에 의한 Hgb의 DH는 $24{\sim}25%$였다. Hgb의 농도는 heme-iron의 분리에 영향을 미쳐서 Hgb의 농도가 2.5%, 5.0%, 10.0%로 증가할수록 heme-iron/peptide(heme-iron의 분리도)는 각각 47.4%, 35.6%, 21.8%로 감소하였으며, 이에 따라 농축율도 감소하였다. Hgb의 가수분해액으로부터 고농도 heme-iron의 분리에 효율적인 pH 영역은 DH에 따라 달라졌으며, DH가 6.3%의 경우는 pH $5.0{\sim}6$에서 heme-iron/peptide의 비가 8.92%, DH가 14.5%인 경우는 pH $4.0{\sim}6.0$에서 $12.1{\sim}19.5%$였으며, DH가 24.3%인 경우는 pH $3.0{\sim}5.0$에서 $34.7{\sim}36.4%$로 가수분해도가 높을수록 고농도 heme-iron의 분리시 최적 PH 범위가 산성 영역으로 이동되었으며, 이 영역의 pH에서 peptide의 용해도 증가로 분리도가 증가되었다. 가수분해액으로부터 분리된 heme-iron의 분자량은 약 1 kDa정도로 hematin과 유사한 분리패턴을 보였다. Pilot scale로 제조한 고농도 heme-iron 제품에서의 heme-iron 함량은 27.1%, heme-iron/peptide 비는 38.7%, 생산수율은 9.3%이었다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권12호
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• pp.1725-1728
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• 2004

An experiment was conducted to investigate the efficiency of transfer of dietary iron sources to eggs of laying hens. Eighty ISA-Brown laying birds of 30 wk old were housed in 40 cages of 2 birds each. Eight birds in four cages were assigned to one of the following ten treatments: T1; control, T2; 100 ppm iron supplementation with iron-methionine chelate (Fe-Met-100), T3; Fe-Met- 200, T4; Fe-Met-300, T5; 100 ppm iron supplementation with iron sulfate ($FeSO_4$-100), T6; $FeSO_4$-200, T7; $FeSO_4$-300, T8; 100 ppm iron supplementation with Availa-$Fe^{(R)}$ (Availa-Fe-100), T9; Availa-Fe-200 and T10; Availa-Fe-300. Results of 40 d feeding trial showed that there were no consistent responses in laying performance by source and level of iron supplementation. However, eggshell strength and color were improved by Fe supplementation. Egg iron content was maximized at 10-15 days after feeding supplemental Fe. Fe- Met was the most effective source in enriching Fe of eggs followed by Availa-Fe and $FeSO_4$. Increasing supplementary Fe level more than 100 ppm was not effective in Fe-Met and Availa-Fe treatments. Average Fe enrichment of 18% was achieved after feeding Fe-Met-100 for 15 d. In conclusion, enrichment of Fe in egg could be effectively achieved by supplementation of Fe-Met-100 for 15 d.

• 자원환경지질
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• 제48권5호
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• pp.391-400
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• 2015

남한은 철강의 수요나 생산에 비해 그 원료가 되는 철광석의 생산이 미약한 반면, 북한은 상당한 철 매장량을 보유하고 있으나 자원량에 비해 생산량이 극히 미진하다. 또한 북한의 폐쇄성으로 인해 북한의 자원에 대한 정보가 미비하고, 그 신뢰성에 의문이 있다. 본 연구는 북한의 철광산 중 세계적인 노천광산으로 알려진 무산광산을 대상으로, Landsat MSS, ASTER 위성영상자료와 수치지형도를 통해 1976~2007년 사이의 자원량과 생산량을 추정하였다. 원격탐사를 통해 산정한 무산광산의 넓이는 1976년을 기준으로 총 약 $6.1km^2$의 면적이 증가하였으며, 광산 내 채광지의 크기는 지도대수기법을 통해 $4.9km^2$로 산정되었다. 또한, 산정된 채광지 내 약 3.2억 $m^3$의 체적을 3차원 모델링을 이용하여 산출한 후, 무산광산과 동일한 암상으로 간주되는 중국 안산층의 철광석 평균밀도와 연산하여 약 7.3억 톤의 자원량과 약 2.4억 톤의 생산량을 추정하였다. 이 수치는 연 평균 810만 톤 수준의 생산량으로, 기존에 보고된 수치와 비교하였을 때, 상당한 일치성을 보였다. 본 연구는 남북자원교류사업을 위한 기초자료로써 유용하게 이용될 수 있을 것으로 기대된다.

• 한국환경과학회지
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• 제29권4호
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• pp.383-393
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• 2020

To increase electrolysis performance, the applicability of seawater to the iron-fed electro-Fenton process was considered. Three kinds of graphite electrodes (activated carbon fiber-ACF, carbon felt, graphite) and dimensionally stable anode (DSA) electrode were used to select a cathode having excellent hydrogen peroxide generation and organic decomposition ability. The concentration of hydrogen peroxide produced by ACF was 11.2 mg/L and those of DSA, graphite, and carbon felt cathodes were 12.9 ~ 13.9 mg/L. In consideration of durability, the DSA electrode was selected as the cathode. The optimum current density was found to be 0.11 A/㎠, the optimal Fe²⁺ dose was 10 mg/L, and the optimal ratio of Fe²⁺ dose and hydrogen peroxide was determined to be 1:1. The optimum air supply for hydrogen peroxide production and Rhodamine B (RhB) degradation was determined to be 1 L/min. The electro-Fenton process of adding iron salt to the electrolysis reaction may be shown to be more advantageous for RhB degradation than when using iron electrode to produce hydrogen peroxide and iron ion, or electro-Fenton reaction with DSA electrode after generating iron ions using an iron electrode.

• Environmental Engineering Research
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• 제20권3호
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• pp.205-211
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• 2015

Reduced forms of iron, such as zero-valent ion (ZVI) and ferrous ion (Fe[II]), can activate dissolved oxygen in water into reactive oxidants capable of oxidative water treatment. The corrosion of ZVI (or the oxidation of (Fe[II]) forms a hydrogen peroxide ($H_2O_2$) intermediate and the subsequent Fenton reaction generates reactive oxidants such as hydroxyl radical ($^{\bullet}OH$) and ferryl ion (Fe[IV]). However, the production of reactive oxidants is limited by multiple factors that restrict the electron transfer from iron to oxygen or that lead the reaction of $H_2O_2$ to undesired pathways. Several efforts have been made to enhance the production of reactive oxidants by iron-induced oxygen activation, such as the use of iron-chelating agents, electron-shuttles, and surface modification on ZVI. This article reviews the chemistry of oxygen activation by ZVI and Fe(II) and its application in oxidative degradation of organic contaminants. Also discussed are the issues which require further investigation to better understand the chemistry and develop practical environmental technologies.

• Environmental Engineering Research
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• 제20권2호
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• pp.121-125
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• 2015

Biohydrogen production from food waste via dark fermentation was conducted by using mixed culture under various environmental conditions (initial pH, initial F/M ratio, initial ferrous iron ($Fe^{2+}$), and temperature condition) in batch reactor. The results revealed that the maximum hydrogen yield of $46.19mL\;H_2/g\;COD_{add}$ was achieved at the optimal conditions (initial pH 8.0, initial F/M ratio 4.0, initial iron concentration 100 mg $FeSO_4/L$ and thermophilic condition ($55{\pm}1^{\circ}C$)). Furthermore, major volatile fatty acid (VFA) productions of butyrate (765.66 mg/L) and acetate (324.69 mg/L) were detected and COD removal efficiency was detected at 66.00%. Therefore, these optimal conditions could be recommended to operate a system.