• Title, Summary, Keyword: 영가철

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Continuous Removal of Nitrate and Coliform using Bipolar ZVI Packed Bed Electrolytic Cell (영가철 충진 복극전해조를 이용한 질산성질소 및 대장균의 연속식 제거)

  • Jeong, Joo-Young;Park, Jeong-Ho;Choi, Won-Ho;Park, Joo-Yang
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.5
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    • pp.651-658
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    • 2011
  • Nitrate is a common contaminant in industrial wastewater and ground water. The maximum contaminant level set by EPA for nitrate of 10 mg/L as N. In this study, nitrate was removed using bipolar ZVI packed bed electrolytic cell that maximized the contact area between each electrode and contaminants under 600 V. Also this study investigates the simultaneously deals with removal of ammonia by operating air stripping tower. In addition to the air stripping also helped to precipitate iron ions to the form of iron oxides. Bipolar ZVI packed bed electrolytic cell was also effective in removing coliform by electrical power. In the continuous experiments for the simulated wastewater (initial nitrate for 25 mg/L as N), maximum 96.3% removal of nitrate was achieved in the applied 600 V at the flow rate of 6 mL/min.

Continuous removal of phosphorus in water by physicochemical method using zero valent iron packed column (영가철 충진 컬럼을 이용한 연속적인 물리화학적 수중 인 제거)

  • Jeong, Jooyoung;Ahn, Byungmin;Kim, Jeongjoo;Park, Jooyang
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.4
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    • pp.439-444
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    • 2013
  • Excessive phosphorus in aquatic systems causes algal bloom resulting in eutrophication, DO depletion, decline in recreational value of water and foul tastes. To treat wastewater containing phosphorus including effluent of wastewater treatment plant, the continuous experiments were performed by using electrochemical way. The spherical ZVI and silica sand which act as physical filter are packed at appropriate volume ratio of 1:2. Electric potential is applied externally which can be changed as per the operational requirement. The results indicate that optimum hydraulic retention time of 36 minutes (10 mL/min at 1 L reactor) was required to meet the effluent standards. Lower concentrations of phosphorus (<10 mg/L as phosphate) were removed by precipitation by contact with iron. Thus, additional electric potential was not required. In order to remove high concentration phosphorus around 150 mg/L as phosphate, external electric potential of 600 V was applied to the reactor.

Effect of Surfactant on Reductive Dechlorination of Trichloroethylene by Zero-Valent Iron (양이온-비이온 혼합계면활성제의 첨가가 영가철을 이용한 TCE환원에 미치는 영향)

  • Shin, Min-Chul;Choi, Hyun-Dock;Yang, Jung-Seok;Baek, Ki-Tae
    • Journal of Soil and Groundwater Environment
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    • v.12 no.6
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    • pp.38-45
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    • 2007
  • Trichloroethylene (TCE) is a representative dense non-aqueous phase liquid (DNAPL) and has contaminated substance environments including soil and groundwater due to leakage and careless. DNPAL, has been treated by surfactant-enhanced aquifer remediation (SEAR). After application of SEAR, groundwater contains still surfactant as well as little amount of residual TCE. Permeable reactive barrier using zero-valent iron (ZW) is a very effective technology to treat the residual TCE in groundwater. In this study, the effect of the residual surfactant on the reductive dechlorination of residual TCE was investigated using ZVI. Mixed surfactant composed of nonioinic surfactant and cationic surfactant was used as a residual surfactant because of toxicity and enhancement of dechlorination rate. Structure of surfactant affected significantly the decrhlorination rate of TCE. Mixed surfactant system with relatively short polyethylene oxide (PEO) chain in nonionic surfactant, cationic surfactant did not affect TCE dechlorination rate. However, mixed surfactant system with relatively long PEO chain in nonionic surfactant shows that TCE dechlorination rate was significantly dependent on fraction of cationic surfactant and HLB of nonionic surfactant. Cationic surfactant with trimethyl ammonium group enhanced reductive dechlorination rate compared to that surfactant with pyridinium group.

Nitrate Reduction without Ammonium Release using Fe-loaded Zeolite

  • Lee Seunghak;Lee Kwanghun;Lee Sungsu;Park Junboum
    • Journal of Soil and Groundwater Environment
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    • v.10 no.1
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    • pp.1-5
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    • 2005
  • Nitrate reduction with zero valent iron $(Fe^0)$ has been extensively studied, but the proper treatment for ammonium byproduct has not been reported yet. In groundwater, however, ammonium is regarded as contaminant species, and particularly, its acceptable level is regulated to 0.5 mg-N/L. for drinking water. This study is focused on developing new material to reduce nitrate and properly remove ammonium by-products. A new material, Fe-loaded zeolite, is derived from zeolite modified by Fe(II) chloride followed by reduction with sodium borohydride. Batch experiments were performed without buffer at two different pH to evaluate the removal efficiency of Fe-loaded zeolite. After 80 hr reaction time, Fe loaded zeolite showed about $60\%$ nitrate removal at initial pH of 3.3 and $40\%$ at pH of 6 with no ammonium release. Although iron filing showed higher removal efficiency than Fe-loaded zeolite at each pH, it released a considerable amount of ammonium stoichiometrically equivalent to that of reduced nitrate. In terms of nitrogen species including $NO_3-N$ and $NH_4^+-N$, Fe-loaded zeolite removed about $60\%\;and\;40\%$ of nitrogen in residual solution at initial pH of 3.3 and 6, respectively, while the removal efficiency of iron filing was negligible.

Evaluation of nanoscale zero valent iron filled column for nitrate reduction (영가철 나노입자가 충진된 컬럼을 이용한 질산성 질소 환원 성능 평가)

  • Hong, Youngpyoe;Seo, Younggyo;Kim, Hyowon;Hwang, Yuhoon
    • Journal of Korean Society of Water and Wastewater
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    • v.32 no.3
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    • pp.243-251
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    • 2018
  • In this study, we compared the MZVI (Microscale Zero-Valent Iron) and NZVI (Nanoscale Zero-Valent Iron) for reactivity and mobility in a column to reduce nitrate, which is a major pollutant in Korea, and investigated the effect of operational parameters on the NZVI filled column. For the comparison of MZVI and NZVI, samples were collected for 990 minutes using fractionator in the similar operation conditions (MZVI 10g, NZVI 2g). The nitrate reduction efficiency of NZVI was about 5 times higher than that of MZVI, which was about 7.45% and 38.75% when using MZVI and NZVI, respectively. In the mobility experiment, the MZVI descended due to gravity while NZVI moved up with water flow due to its small size. Furthermore, the optimum condition of NZVI filled column was determined by changing the flow rate and pH. The amount of Fe ions was increased as the pH of the nitrate solution was lowered, and the nitrate removal rate was similar due to the higher yield of hydroxyl groups. The removal rate of nitrate nitrogen was stable while flow rate was increased from 0.5 mL/min to 2.0 mL/min (empty bed contact time: 2.26 min to 0.57 min). NZVI has a high reduction rate of nitrate, but it also has a high mobility, so both of reactivity and mobility need to be considered when NZVI is applied for drinking water treatment.

Reduction Characteristics of Triclosan using Zero-valent Iron and Modified Zero-valent Iron (영가철 및 개질 영가철을 이용한 triclosan의 환원분해 특성)

  • Choi, Jeong-Hak;Kim, Young-Hun
    • Journal of Environmental Science International
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    • v.26 no.7
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    • pp.859-868
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    • 2017
  • In this study, the reductive dechlorination of triclosan using zero-valent iron (ZVI, $Fe^0$) and modified zero-valent iron (i.e., acid-washed iron (Aw/Fe) and palladium-coated iron (Pd/Fe)) was experimentally investigated, and the reduction characteristics were evaluated by analyzing the reaction kinetics. Triclosan could be reductively decomposed using zero-valent iron. The degradation rates of triclosan were about 50% and 67% when $Fe^0$ and Aw/Fe were used as reductants, respectively, after 8 h of reaction. For the Pd/Fe system, the degradation rate was about 57% after 1 h of reaction. Thus, Pd/Fe exhibited remarkable performance in the reductive degradation of triclosan. Several dechlorinated intermediates were predicted by GC-MS spectrum, and 2-phenoxyphenol was detected as the by-product of the decomposition reaction of triclosan, indicating that reductive dechlorination occurred continuously. As the reaction proceeded, the pH of the solution increased steadily; the pH increase for the Pd/Fe system was smaller than that for the $Fe^0$ and Aw/Fe system. Further, zero-order, first-order, and second-order kinetic models were used to analyze the reaction kinetics. The first-order kinetic model was found to be the best with good correlation for the $Fe^0$ and Aw/Fe system. However, for the Pd/Fe system, the experimental data were evaluated to be well fitted to the second-order kinetic model. The reaction rate constants (k) were in the order of Pd/Fe > Aw/Fe > $Fe^0$, with the rate constant of Pd/Fe being much higher than that of the other two reductants.

The Pathway and Characteristics for Decomposition of Fenitrothion by Zerovalent Iron (ZVI) (영가철에 의한 Fenitrothion의 분해 경로 및 특성)

  • Lee, Dong-Yoon;Moon, Byung-Hyun
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.3
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    • pp.157-161
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    • 2011
  • This study investigated decomposition the pathway and characteristics of fenitrothion, which is applied on the golf course for pesticide, by ZVI in batch reactor. The removal efficiencies of the pure fenitrothion and the commercial fenitrothion in Smithion by ZVI were compared. The fenitrothion was converted to 3-Methyl-4-nitrophenol and 4-Amino-m-cresol by ZVI. The fenitrothion decomposition rate by ZVI could be expressed by the first order reaction. As increasing the ZVI dosages, the first order rate constants and removal efficiencies increased. The surface area normalized rate constants for the pure fenitrothion and the commercial fenitrothion were 0.0398 and 0.1312 ($L/m^2{\cdot}hr$), respectively. The decomposition of the commercial fenitrothion in Smithion was faster than that of the pure fenitrothion by ZVI, the surfactant in Smithion lead to enhances solubility of fenitrothion and disperse ZVI.

Reduction of Nitrate-nigrogen by Zero-valent Iron Adhered in Mesoporous Silicas (메조기공 실리카에 부착된 영가철을 이용한 질산성 질소의 환원)

  • Yeon, Kyeong-Ho;Lee, Seunghak;Lee, Kwanyong;Park, Yong-Min;Kang, Sang-Yoon;Lee, Jae-Won;Choi, Yong-Su;Lee, Sang-Hyup
    • Journal of Korean Society of Water and Wastewater
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    • v.21 no.1
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    • pp.139-147
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    • 2007
  • For environmental remediation of a contaminated groundwater plume, the use of zero-valent metal represents one of the latest innovative technologies. In this study, the effects of denitrification by zero-valent iron adsorbed in mesoporous silicas have been studied for groundwater contaminant degradation. The mesoporous silica was functionalized with 3-mercaptopropyltrimethoxysilane (MPTS) ligands and the zero-valent iron precipitated in the mesopore of granular silica was made by $FeCl_2$ and $NaBH_4$. Hydrogen was exchanged with $Fe^{2+}$ ions in the granular silicas. And then the ions were reduced by sodium borohydride in the mesoporous silicas. The surface area of the silica determined via the BET method ranged from 858 to $1275m^2/g$. The reductive reaction of nitrate-nitrogen indicated that the degradation of nitrate-nitrogen appeared to be pseudo first-order with the observed reaction rate constant kobs ($0.1619h^{-1}$) and to be directly proportional to the specific surface area. Therefore, the mesoporous silica with nano zero-valent iron proposed as a novel treatment strategy for contaminated groundwater was successfully implemented herein for the removal of nitrate-nitrogen.

Functional Ceramic Filter Fabrication for As Removal in Aqueous Solutions (수용액상의 As 제거를 위한 기능성 세라믹 필터 제조)

  • Cho, Kanghee;Choi, Nag-Choul;Kim, Song-Bae;Park, Cheon-Young
    • Journal of the Mineralogical Society of Korea
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    • v.30 no.4
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    • pp.173-178
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    • 2017
  • In this study, the effect of sintering temperature and zero valent iron (ZVI) content on the physical properties of functional ceramic filter(alumina based materials) such as strength and porosity were investigated. The fabrication process of the functional ceramic filter were performed under various sintering temperature ($1150^{\circ}C$, $1250^{\circ}C$) and ZVI content (10, 20, 30, 50%) conditions. With increasing the sintering temperature and ZVI content, strength was increased but porosity was decreased. The physical properties for functional ceramic filter showed that the strength and porosity were obtained under ZVI content (50%) and sintering temperature ($1250^{\circ}C$) of 99.01 MPa and 34.5%, respectively.