• 제목, 요약, 키워드: zerovalent iron

검색결과 30건 처리시간 0.035초

Removal of Arsenic from Leachate of Tailing using Laboratory-synthesized Zerovalent Iron

  • Kim, Soon-Oh;Jung, Young-Il;Cho, Hyen-Goo;Park, Won-Jeong;Kim, In-Seon
    • Journal of Applied Biological Chemistry
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    • v.50 no.1
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    • pp.6-12
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    • 2007
  • Feasibility of laboratory-synthesized zerovalent iron was investigated to remove arsenic from leachates of tailings taken from an Au-Ag abandoned mine. The tailings were seriously contaminated with arsenic, and its potential adverse effect on the ecosystems around the mine seems to be significantly high. Long-term column experiments were conducted for about 3.5 months to evaluate the effectiveness of the synthesized zerovalent iron for removal of arsenic. Over than 95% removal efficiency of As was observed in the zerovalent iron mediated tests. In addition, the XRD data suggest that the corrosion products of ZVI were identified magnetite, maghemite, goethite, and lepidocrocite, all of which support Fe(II) oxidation as an intermediate step in the zerovalent iron corrosion process. The results indicate that arsenic can be removed from the tailing-leachate by the mechanism of coprecipitation and/or adsorption onto those iron oxides formed from ZVI corrosion.

Degradation of the Herbicide Butachlor by Laboratory-synthesized Nanoscale $Fe^0$ in Batch Experiments

  • Kim, Hyang-Yeon;Kim, In-Kyung;Han, Tae-Ho;Shim, Jae-Han;Kim, In-Seon
    • Journal of Applied Biological Chemistry
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    • v.49 no.3
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    • pp.101-105
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    • 2006
  • Degradation of the herbicide butachlor was investigated using laboratory-synthesized zerovalent iron ($Fe^0$). The synthesized zerovalent iron was determined to be nanoscale powder by scanning electron microscopic analysis. To investigate degradation of butachlor using the synthesized nanoscale zerovalent iron, time-course batch experiments were conducted by treating the solution of butachlor formulation with the iron. More than 90% degradation of butachlor was observed by iron treatment within 24 h. The synthesized nanoscale zerovalent iron showed an increase in particle aggregation in the batch tests. Green rust formation and a pH drop in solutions were observed, suggesting that the oxidation of the iron occurred. When the iron was extracted with dichloromethane, a negligible concentration was found in the extract, suggesting that butachlor did not bind to the iron particles. GC/MS analysis detected the dechlorinated product as a major degradation product of butachlor in the solutions. The data indicate that laboratory-synthesized zerovalent iron functioned as a reductant to remove electron-withdrawing chlorine, giving the dechlorinated product.

Zerovalent Iron 및 Manganese Oxide에 의한 살균제 Chlorothalonil의 탈염소화 (Dechlorination of the Fungicide Chlorothalonil by Zerovalent Iron and Manganese Oxides)

  • 윤종국;김태화;김장억
    • 농약과학회지
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    • v.12 no.1
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    • pp.43-49
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    • 2008
  • Arylnitrile계 살균제인 chlorothalonil의 탈염소화를 촉진시키기 위하여 금속촉매인 zerovalent iron(ZVI) 및 manganese oxide(pyrolusite 및 birnessite)를 수중 처리하여 pH에 따른 chlorothalonil의 분해정도, 탈염소화 그리고 분해산물의 구조를 조사하였다. ZVI, pyrolusite 및 birnessite를 처리하였을 경우 PH가 낮을수록 chlorothalonil의 분해효율은 높게 나타났다. pH 5.0에서 ZVI, pyrolusite 및 birnessite를 각각 1.0%(v/w) 처리하였을 때 chlorothalonil의 분해반감기는 ZVI 4.7시간, pyrolusite 13.46시간 및 birnessite 21.38시간으로 나타났다. Chlorothalonil의 탈염소화 정도를 나타내는 D/N value의 평균값은 ZVI, pyrolusite 및 birnessite를 처리하였을 경우 각각 2.85, 1.12 및 1.09 이었다. Chlorothalonil의 분해산물은 GC-MS를 이용하여 분석한 결과 pyrolusite와 birnessite에 의해 chloride ion이 하나 이탈된 trichloro-1,3-dicyanobenzene과 둘 이탈된 dichloro-1,3-dicyanobenzene으로 확인되었으며, ZVI에 의한 분해산물은 pyrolusite, birnessite의 분해산물과 동일한 trichloro-1,3-dicyanobenzene, dichloro-1,3-dicyanobenzene을 비롯하여 환원이 더 진행된 chloro-1,3-dicyanobenzene과 chlorocyanobenzene으로 확인되었다.

Preparation, characterization and comparison of antibacterial property of polyethersulfone composite membrane containing zerovalent iron or magnetite nanoparticles

  • Dizge, Nadir;Ozay, Yasin;Simsek, U. Bulut;Gulsen, H. Elif;Akarsu, Ceyhun;Turabik, Meral;Unyayar, Ali;Ocakoglu, Kasim
    • Membrane Water Treatment
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    • v.8 no.1
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    • pp.51-71
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    • 2017
  • Antimicrobial polyethersulfone ultrafiltration membranes containing zerovalent iron ($Fe^0$) and magnetite ($Fe_3O_4$) nanoparticles were synthesized via phase inversion method using polyethersulfone (PES) as membrane material and nano-iron as nanoparticle materials. Zerovalent iron nanoparticles (nZVI) were prepared by the reduction of iron ions with borohydride applying an inert atmosphere by using $N_2$ gases. The magnetite nanoparticles (nMag) were prepared via co-precipitation method by adding a base to an aqueous mixture of $Fe^{3+}$ and $Fe^{2+}$ salts. The synthesized nanoparticles were characterized by scanning electron microscopy, X-ray powder diffraction, and dynamic light scattering analysis. Moreover, the properties of the synthesized membranes were characterized by scanning electron microscopy energy dispersive X-ray spectroscopy and atomic force microscopy. The PES membranes containing the nZVI or nMag were examined for antimicrobial characteristics. Moreover, amount of iron run away from the PES composite membranes during the dead-end filtration were tested. The results showed that the permeation flux of the composite membranes was higher than the pristine PES membrane. The membranes containing nano-iron showed good antibacterial activity against gram-negative bacteria (Escherichia coli). The composite membranes can be successfully used for the domestic wastewater filtration to reduce membrane biofouling.

살균제 Tolclofos-methyl의 화학적 처리에 의한 분해 (Degradation of Fungicide Tolclofos-methyl by Chemical Treatment)

  • 신갑식;전영환;김효영;황정인;이상만;신재호;김장억
    • 한국환경농학회지
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    • v.29 no.4
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    • pp.396-401
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    • 2010
  • 살균제 tolclofos-methyl은 인삼 및 인삼 경작지 토양에서 빈번히 검출되고 있어 그 안전성이 문제시되고 있다. 이에 tolclofos-methyl을 토양 slurry조건에서 여러 종류의 화학적 처리를 통하여 분해되는 정도를 조사하였다. ZVI를 처리한 경우 uZVI가 aZVI보다 tolclofos-methyl의 분해를 촉진 하였으며 uZVI와 ZVZn의 경우에는 ZVZn가 더 촉진시키는 것으로 나타났다. uZVI와 ZVZn 처리구에서는 처리량이 증가할수록 그리고 입경이 작을수록 더 잘 분해되는 것으로 나타났다. pH 4.0 이하의 산성 조건하에서 처리된 ZVI는 tolclofos-methyl의 분해를 더욱 촉진시켜 수용액에서 24시간 만에 94.4%까지 분해시켰다. Fenton 반응을 이용한 tolclofos-methyl의 분해는 iron source로 $Fe_2(SO_4)_3$가 가장 효과적이었으며, $H_2O_2$ 500 mM 처리구에서 93.5%까지 분해되었다. Sodium bisulfite를 이용한 토양 slurry 중의 tolclofos-methyl의 분해는 처리량이 증가할수록 분해가 촉진되었으며 50 mM 처리구에서 52.9%가 분해되었다.

Zerovalent Iron에 의한 유기염소계 살충제 Endosulfan의 탈염소화 (Dechlorination of Organochlorine Insecticide, Endosulfan by Zerovalent Iron)

  • 신현수;김택겸;김장억
    • 한국환경농학회지
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    • v.28 no.2
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    • pp.202-208
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    • 2009
  • 유기염소계 살충제 endosulfan과 이의 토양 중 주 분해산물인 endosulfan sulfate의 ZVI에 의한 분해정도와 분해산물을 조사하였다. ZVI처리에 의해서 수용액내에서 endosulfan과 endosulfan sulfate는 pH가 낮을수록 분해율이 높았으며 pH 3.0에서 ${\alpha}$-endosulfan은 28%, endosulfan sulfate는 90%정도 분해되었고 acetone/water(50/50, v/v) 용액에서는 ${\alpha}$-endosulfan은 65%, endosulfan sulfate는 92%정도 분해되었다. ZVI에 의해 ${\alpha}$-endosulfan 및 endosulfan sulfate는 분해되어 2개의 미확인 물질을 생성하였다. 반응시간에 따른 반응속도와 반감기를 비교해 보면 endosulfan sulfate가 ${\alpha}$-endosulfan에 비해 빠르게 분해되는 양상을 보였다. ZVI의 처리에 인해 ${\alpha}$-endosulfan과 endosulfan sulfate에서 생성된 2개의 미확인 물질은 GC-MS로 분석한 결과, 하나의 $Cl^-$$H^+$로 치환된 구조이성질체로 나타났다.

Synthesis of Nanoscale Zerovalent Iron Particle and Its Application to Cr(VI) Removal from Aqueous Solutions

  • Awad, Yasser M.;Abdelhafez, Ahmed A.;Ahmad, Mahtab;Lee, Sang-Soo;Kim, Rog-Young;Sung, Jwa-Kyung;Ok, Yong-Sik
    • 한국환경농학회지
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    • v.29 no.4
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    • pp.402-407
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    • 2010
  • Zerovalent iron (ZVI) is one of the most commonly used metallic reducing agents for the treatment of toxic contaminants in wastewater. Traditional ZVIs are less effective than nanoscale ZVI (nZVI) due to prolonged reaction time. However, the reactivity can be significantly increased by reducing the size of ZVI particles to nanoscale. In this study, nZVI particles were synthesized under laboratory condition and their efficiency in removing hexavalent chromium (Cr(VI)) from aqueous solutions were compared with commercially available ZVI particles. The results showed that the synthesized nZVI particles (SnZVI) reduced >99% of Cr(VI) at the application rate of 0.2% (w/v), while commercial nZVI (CnZVI) particles resulted in 59.6% removal of Cr(VI) at the same application rate. Scanning electron micrographs (SEM) and energy dispersive spectra (EDS) of the nZVI particles revealed the formation of Fe-Cr hydroxide complex after reaction. Overall, the SnZVI particles can be used in treating chromium contaminated wastewater.

Enhance degradation of insecticide chlorpyrifos by iron salts and potassium persulfate during zerovalent iron treatment in aqueous solution

  • Rahman, M. Mokhlesur;Hwang, Jung-In;Kwak, Se-Yeon;Kim, Jang-Eok
    • Journal of Applied Biological Chemistry
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    • v.61 no.4
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    • pp.383-389
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    • 2018
  • Degradation of the insecticide O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate (chlorpyrifos) in aqueous solution was investigated using iron salts and potassium persulfate during ZVI treatment through a series of batch experiments. The degradation rate of chlorpyrifos increased with increases in the concentrations of iron salts and potassium persulfate in the aqueous system. Ferric chloride was found to be the most effective iron salt for the ZVI-mediated degradation of chlorpyrifos in aqueous solution. Further, the iron salts tested could be arranged in the following order in terms of their effectiveness: $FeCl_3$> $Fe_2(SO_4)_3$> $Fe(NO_3)_3$. The persulfate-ZVI system could significantly degrade chlorpyrifos present in the aqueous medium. This revealed that chlorpyrifos degradation by treatment with $Fe^0$ was promoted on adding ferric chloride and potassium persulfate. The kinetics of the degradation of chlorpyrifos by persulfate-amended $Fe^0$ was higher than that for iron-salt-amended $Fe^0$. This suggests that using a sequential $Fe^0$ reduction-ferric chloride or $Fe^0$ reduction-persulfate process may be an effective strategy to enhance the removal of chlorpyrifos in contaminated water.

Zerovalent iron-montmorillonite 복합체에 의한 chlorothalonil의 분해 (Degradation of Chlorothalonil by Zerovalent Iron-Montmorillonite Complex)

  • 최충렬;박만;이동훈;이인구;송경식;강상재;김장억
    • 한국환경농학회지
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    • v.25 no.3
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    • pp.257-261
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    • 2006
  • 본 연구에서는 유기성 화학물질로 오염된 지하수, 수질 및 토양의 효과적인 복원제로 활용되고 있는 ZVI의 반응성 및 안정성을 높이기 위하여 ZVI에 montmorillonite를 첨가하여 합성된 ZVI-Mt 복합체의 특성과 유기염소계 오염물질의 효과적인 제거제로서의 활용가능성을 조사하였다. X-선회절분석 결과 ZVI는 $44.9^{\circ}$ 부근에서 broad reflection peak를 나타내었으며, ZVI-Mt 복합체는 ZVI와 montmorillonite의 전형적인 peak가 관찰되었다. ZVI-Mt 복합체의 형태는 montmorillonite 층이 추형의 ZVI 입자를 부분적으로 둘러싸고 있었으며, ZVI가 공기 중의 산소에 의해 급격히 산화되는 것을 방지할 수 있는 구조적 형태를 나타내었다. ZVI-Mt 복합체에 의한 chlorothalonil의 분해율이 ZVI에 비해 보다 빠르고 높게 나타났으며, 반응 60분 후에는 chlorothalonil이 완전히 분해되었다. ZVI, ZVI-Mt(2:1) 및 ZVI-Mt (1:1) 모두 pH가 낮을수록 chlorothalonil의 분해가 잘 일어났으며, 모든 pH 영역에서 ZVI 보다 ZVI-Mt에 의한 chlorothalonil의 분해 효율이 높게 나타났다. 그러므로 기존의 방법에 의해 ZVI를 합성하는 것 보다는 montmorillonite를 혼합하여 복합체를 형성하는 것이 montmorillonite 층의 card section현상에 의해 ZVI의 환원력과 안정성을 증가시키는 것으로 나타났다.