• Title, Summary, Keyword: 영가철

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Effect of Organic Matter and Moisture Content on Reduction of Cr(VI) in Soils by Zerovalent Iron (영가철에 의한 토양 Cr(VI) 환원에 미치는 유기물 및 수분함량 영향)

  • Yang, Jae-E.;Lee, Su-Jae;Kim, Dong-Kuk;Oh, Sang-Eun;Yoon, Sung-Hwan;Ok, Yong-Sik
    • Korean Journal of Environmental Agriculture
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    • v.27 no.1
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    • pp.60-65
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    • 2008
  • Current soil remediation principles for toxic metals have some limitations even though they vary with different technologies. An alternative technology that transforms hazardous substances into nonhazardous ones would be environmentally beneficial. Objective of this research was to assess optimum conditions for Cr(VI) reduction in soils as influenced by ZVI(Zero-Valent Iron), organic matter and moisture content. The reduction ratio of Cr(VI) was increased from 37 to 40% as organic matter content increased from 1.07 to 1.75%. In addition, Cr(VI) concentration was reduced as soil moisture content increased, but the direct effect of soil moisture content on Cr(VI) reduction was less than 5% of the Cr(VI) reduction ratio. However, combined treatment of ZVI(5%), organic matter(1.75%) and soil moisture(30%) effectively reduced the initial Cr(VI) to over 95% within 5 days and nearly 100% after 30 days by increasing oxidation of ZVI and concurrent reduction of Cr(VI) to Cr(III). The overall results demonstrated that ZVI was effective in remediating Cr(VI) contaminated soils, and the efficiency was synergistic with the combined treatments of soil moisture and organic matter.

Removal of Nitrate Nitrogen for Batch Reactor by ZVI Bipolar Packed Bed Electrolytic Cell (영가철 충진 회분식 복극전해조에 의한 질산성 질소 제거)

  • Jeong, Joo Young;Park, Jeong Ho;Choi, Won Ho;Park, Joo Yang
    • Journal of The Korean Society of Civil Engineers
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    • v.31 no.2B
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    • pp.187-192
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    • 2011
  • Nitrate nitrogen is common contaminant in groundwater aquifers, its concentration is regulated many countries below 10 mg/L as N (As per WHO standards) in drinking water. An attempt was made to get optimal results for the treatment of nitrate nitrogen in groundwater by conducting various experiments by changing the experimental conditions for ZVI bipolar packed bed electrolytic cell. From the experimental results it is evident that the nitrate nitrogen removal is more effective when the reactor conditions are maintained in acidic range but when the acidic environment changes to alkaline due to the hydroxide formed during the process of ammonia nitrogen there by increasing the pH reducing the hydrogen ions required for reduction which leads to low effectiveness of the system. In the ZVI bipolar packed bed electrolytic cell, the packing ratio of 0.5~1:1 was found to be most effective for the treatment of nitrate nitrogen because ZVI particles are isolated and individual particle act like small electrode with low packing ratio. It is seen that formation of precipitate and acceleration of clogging incrementally for packing ratio more than 2:1, decreasing the nitrate nitrogen removal rate. When the voltage is increased it is seen that kinetics and current also increases but at the same time more electric power is consumed. In this experiment, the optimum voltage was determined to be 50V. At that time, nitrate nitrogen was removed by 94.9%.

The effect of surfactant on reductive dechlorination of TCE (계면활성제가 영가철을 이용한 TCE처리에 미치는 영향)

  • Sin Min-Cheol;Kim Do-Hyeong;Choi Hyeon-Deok;Seo Chang-Il;Baek Gi-Tae
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • pp.198-202
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    • 2006
  • 국내의 대표적인 지하수 오염물질인 trichloroethylene(TCE)을 반응벽체의 일종인 영가철을 이용하여 처리할 때 계면활성제가 미치는 영향을 다양한 계면활성제를 이용하여 조사하였다. 비이온성 계면활성제와 음이온성 계면활성제는 TCE의 탈염소화 반응속도는 감소시켰으나 양이온성 계면활성제는 임계미셀농도 (CMC) 미만에서는 반응속도를 증가시켰으나, CMC 이상의 농도에서는 반응속도를 감소시켰다. 양이온성 계면활성제는 TCE의 철 표면 흡착을 증가시켜, 철 표면에서 일어나는 TCE의 탈염소화 반응속도를 증가시키는 것으로 사료된다.

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Reductive Degradation Kinetics and Pathways of Chlorophenolic Organic Pollutants by Nickel-Coated Zero Valent Iron (니켈로 코팅된 영가금속을 이용한 염소계 페놀화합물의 반응경로 및 반응율 평가)

  • Shin, Seung-Chul;Kim, Young-Hun;Ko, Seok-Oh
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.5
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    • pp.487-493
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    • 2006
  • Reductive dechlorination of chlorophenols by nickel coated iron was investigated to understand the feasibility of using Ni/Fe for the in situ remediation of contaminated groundwater. Zero Valent Iron(ZVI) was amended with Ni(II) ions to form bimetal(Ni/Fe). Dechlorination of five chlorophenol compounds and formation of intermediates were examined using Ni/Fe. Rate constant for each reaction pathway was quantified by the numerical integration of a series of differential rate equation. Experimental results showed that the sequence of hydrodechlorination rate constant was in the order of 2-CP>4-CP>2,4-DCP>2,4,6-TCP>2,6-DCP. The hydrodechlorination pathways for the conversion of each chlorophenol compound involves a full dechlorination to phenol via both concerted and stepwise mechanisms. Reaction pathways and corresponding kinetic rate constants were suggested based on the experiments and numerical simulations.

As (v) immobilization in an aqueous solution by zerovalent iron under various environmental conditions (영가철(Zerovalent Iron)을 이용한 수용액 중 비소(V)의 불용화)

  • Yoo, Kyung-Yoal;Ok, Yong-Sik;Yang, Jae-E.
    • Korean Journal of Environmental Agriculture
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    • v.26 no.3
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    • pp.197-203
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    • 2007
  • Zerovalent iron (ZVI) has been widely used in the removal of environmental contaminants from water. The objective of this research was to assess the efficiency of ZVI for immobilization of As (V) in the contaminated water under various chemical conditions. Batch-type experiments showed that the immobilization process followed a first-order kinetic model. Rate constant (k) of the reaction increased consistently and proportionally as increasing ZVI concentrations from 1% (0.158 $hr^{-1}$) to 3% (0.342 $hr^{-1}$), and temperatures from $15^{\circ}C$ (0.117 $hr^{-1}$) to $35^{\circ}C$ (0.246 $hr^{-1}$), respectively. Whereas the rate constant decreased as increasing As (V) concentrations from 1 mg $\Gamma^{-1}$ (0.284 $hr^{-1}$) to 3 mg $\Gamma^{-1}$ (0.153 $hr^{-1}$), and the initial pH from 3 (0.393 $hr^{-1}$) to 9 (0.067 $hr^{-1}$), respectively. Results demonstrated that As (V) in an aqueous solution was rapidly immobilized by ZVI treatments. Zerovalent iron was fast method for remediation of As (V) contaminated water.

Reduction of Nitrate-Nitrogen by Zero-valent Iron Nanoparticles Deposited on Aluminum yin Electrophoretic Method (전기영동법으로 알루미늄에 침적된 영가 철 나노입자에 의한 질산성 질소의 환원)

  • Ryoo, Won
    • Clean Technology
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    • v.15 no.3
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    • pp.194-201
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    • 2009
  • Reductive reactivity of zero-valent iron nanoparticles was investigated for removal of nitrate-nitrogen which is considered one of the major water pollutants. To elucidate the difference in reactivity between preparation methods, iron nanoparticles were synthesized respectively from microemulsion and aqueous solution of ferric ions. Iron nanoparticles prepared from microemulsion were deposited on aluminum by electrophoretic method, and their reaction kinetics was compared to that of the same nanoparticles suspended in aqueous batch reaction. With an approximation of pseudo-first-order reaction, rate constants for suspended nanoparticles prepared from microemulsion and dilute aqueous solution were $3.49{\times}10^{-2}min^{-1}$ and $1.40{\times}10^{-2}min^{-1}$, respectively. Iron nanoparticles supported on aluminum showed ca. 30% less reaction rate in comparison with the identical nanoparticles in suspended state. However, supported nanoparticles showed the superior effectiveness in terms of nitrate-nitrogen removal per zero-valent iron input especially when excess amounts of nitrates were present. Iron nanoparticles deposited on aluminum maintained reductive reactivity for more than 3 hours, and produced nitrogen gas as a final reduction product of nitrate-nitrogen.

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Analysis of aqueous environment iron dissolution in different conditions (조건의 변화에 따른 수중 환경 내에서의 철 용해 분석)

  • Bae, Yeun-Ook;Min, Jee-Eun;Park, Jae-Woo
    • 한국방재학회:학술대회논문집
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    • pp.807-810
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    • 2008
  • Permeable reactive barriers containing Zero-valent iron (ZVI) are used to purify ground-water contaminants. One of the representative contaminant is trichloroethylene (TCE). ZVI can act as a reducing agent of TCE. When ZVI is oxidized to Ferric iron, TCE reduced to Ethene, which is non-harmful matter. As a ZVI becomes ferric iron, the reducing effect decreases and iron becomes unavailable. So, constant reduction of TCE requires the regular supply of reducing agent. So, we use Iron-reducing bacteria(IRB) to extend the TCE degrading ability. We perform three experiment DI water, DI water with medium, and DI water with medium and IRB. By the experiment we try to found the dissolve ability.

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Removal of Nitrate in Groundwater by Bipolar ZVI Packed Bed Electrolytic Cell at Field Pilot (지하수중의 질산성질소 제거를 위한 영가철 충진 복극전해조의 현장적용에 관한 연구)

  • Na, So-Jeong;Jeong, Joo-Young;Kim, Han-Ki;Park, Joo-Yang
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.6
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    • pp.989-994
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    • 2011
  • Nitrate contamination of groundwater is a common problem throughout intensive agriculture areas (non-point source pollution). Current processes (e.g. ion exchange and membrane separation) for nitrate removal have various disadvantages. The objective of this study was to evaluate electrochemical method such as electroreduction using bipolar ZVI packed bed electrolytic cell to remove nitrate from groundwater at field pilot. In addition ammonia stripping tower continuously removed up to 77.0% of ammonia. Bipolar ZVI packed bed electrolytic cell also removed E.coli. In the field pilot experiment for groundwater in 'I' city (average nitrate 30~35 mg N/L, pH 6.4), maximum 99.9% removal of nitrate was achieved in the applied 600 V.

Dechlorination of Atrazine in Sediment Using Zero Valent Iron (영가철($Fe^0$)을 이용한 퇴적물내 Atrazine의 탈염소화)

  • Kim, Geon-Ha;Jeong, Woo-Hyeok;Choe, Seung-Hee
    • Journal of Soil and Groundwater Environment
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    • v.11 no.4
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    • pp.33-40
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    • 2006
  • Residual pesticides discharged from diffuse sources at agricultural area in association with suspended solid will be settled at downstream, and may degrade surface water quality. This research studied dechlorination kinetic of atrazine, one of triazine-category herbicide, using zero-valent iron (ZVI) in sediment. It can be observed from the experiments that buffer capacity of sediment helped pH maintained beutral, resulted in continuous dechlorination. Sediments were spiked with atrazine at 10, 30, and 50 mg atrazine/L of total sediment for batch experiments. Dechlorination constants were $1.38x10^{-1}/d$ for the initial concentration of 10 mg/L, $1.29x10^{-l}/d$ for 30 mg/L, and $7.43x10^{-2}/d$ for 50 mg/L while dechlorination constants of initial concentration of 50 mg/L without ZVI adding were estimated as $3.05x10^{-2}/d. Half lifes atrazine by ZVI were estimated as 5.03 d fur 10 mg/L, 5.38 d for 30 mg/L, and 9.33 d for 50 mg/L, respectively.