• 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.

• 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.

• Membrane and 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.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.269-273
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• 2007

Occurrence of malodor could cause adverse impacts on human health and increase public interest. Therefore, scientific methods to decrease odor is required. Endeavor to decrease odor from compost however has not fully been successful. The purpose of this research is assessment of some amendments to reduce $NH_3$ from immature composts. Calcium hydroxide was applied to composts due to it's characteristics to increase pH. Activated carbon and zerovalent iron (ZVI) were selected because of their adsorption properties. The research results were as follows: Calcium hydroxide, activated carbon, zerovalent iron increased the composting temperature above $60^{\circ}C$. The addition of calcium hydroxide, activated carbon, and ZVI to compastry process increased pH 8.6 - 8.8 from $1^{st}$ day to $14^{th}$ day. During the 14 days of composting, addition of calcium hydroxide, activated carbon and ZVI changed EC from $2.15-0.66dS\;m^{-1}$, $1.48-1.11dS\;m^{-1}$, respectively and $1.77-0.68dS\;m^{-1}$. The difference in EC of the compost was due to irregularities of samples. Organic matter in the compost decreased through out theexcept control. The $NH_4-N/NO_3-N$ ratio of all experimental compost increased through the process. The addition of activated carbon, calcium hydroxide and ZVI decreased $NH_3$ from 0.1ppm, 0.7ppm and 1.7ppm more than the control (pig manure and sawdust), 9.3ppm, in 30 days of composting. In conclusion, odor from prematured compost decreased by addition of chemicals like calcium hydroxide, activated carbon, zerovalent iron. Moreover, use of these $NH_3$ reducers alone or together combined at different periods of composting etc. could decrease $NH_3$.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.157-161
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• 2006

The performance of abiotic degradation of oxadiazon was investigated by applying zerovalent iron(ZVI), potassium permanganate($KMnO_4$) and titanium dioxide($TiO_2$) in the contaminated water. Experimental conditions allowed the disappearance of oxadiazon in the abiotic system. The degradation of this herbicide was monitored in buffer solutions having pH 3, 5 and 7 in the presence of iron powder in which the maximum degradation rate was achieved at acidic condition(pH 3) by 2% of ZVI treatment. The oxidative degradation of oxadiazon was observed in aqueous solution by $KMnO_4$ at pH 3, 7 and 10 in which the highest disappearance rate was found at neutral pH when treated with 2% of $KMnO_4$. The catalytic degradation of oxadiazon in $TiO_2$ suspension was obtained under dark and UV irradiation conditions. UV irradiation enhanced the degradation of oxadiazon in aquatic system in the presence of $TiO_2$. Conclusively, the remediation strategy using these abiotic reagents could be applied to remove oxadiazon from the contaminated water.

• 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.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.631-638
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• 2010

The objective of this study was to evaluate the efficiency of zerovalent iron and basic oxygen furnace slag on arsenic stabilization in soils. For this, arsenic (V) contaminated soil and roxarsone contaminated soil were incubated after incorporation with zerovalent iron (ZVI) or basic oxygen furnace slage (BOFS) at four different levels (0%, 1%, 3%, and 5%) for 30 days and then the residual concentrations of arsenic were analysed following extraction with aqua reqia, 1N HCl and 0.01 M $CaCl_2$. The total concentration of arsenic was 2,285 mg/kg in the As(V) contaminated soil and 6.5 mg/kg in the roxarsone contaminated soil. 1 N HCl extractable arsenic concentration in the As(V) contaminated soil was initially 1,351 mg/kg and this was significantly declined by 713~1,034 mg/kg following incubation with ZVI while BOFS treatment showed no effect on the stabilization of inorganic arsenate except 5% treatment which showed around 100 mg/kg reduction in 1N HCl extractable arsenic. Similarly, in the roxarsone contaminated soil 1N HCl extractable concentration of arsenic was reduced from 3.13 mg/kg to 0.69 mg/kg with ZVI treatment increased from 1% to 5% while BOFS treatment did not lead to any statistically significant reduction. Available (0.01M $CaCl_2$ extractable) arsenic was initially 0.85 mg/kg in the As(V) contaminated soil and this declined by 0.79 mg/kg following incorporation with 5% ZVI, which accounted for more than 90% of the available As in the control. When As(V)-contaminated soil was treated with BOFS, the available arsenic was increased due to competing effect of the phosphate originated from BOFS with arsenate for the adsorption sites. For the roxarsone contaminated soil, the greater the treatment of ZVI or BOFS, the lower the available arsenic concentration although it was still higher than that of the control.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.229-241
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• 2008

In order to investigate stabilization effect on As-contaminated soils treated by zero-valent iron(ZVI) and industrial by-products, batch tests and column tests were carried out with As-contaminated soils collected from farmland around the abandoned mine site. In batch tests, ZVI and industrial by-products(blast furnace slag, steel refining slag and oyster shell powder) were used as treatment materials to reduce As. Industrial by-products were mixed with As-contaminated soils, in the ratio of 1%, 3%, 5% and 7% on the weight base of dried soil. After incubation, all samples showed the reduction of As concentration and it was expected that ZVI and steel refining slag were effective treatment materials to remove As among treatment materials used in batch test. In column tests, columns were made by acrylic with the dimension of diameter=10cm, height=100cm, thickness=1cm and these columns were filled with untreated soils and treated soils mixed with ZVI and steel refining slag(mixing ratio=3%). Distilled water was discharged into the columns with the velocity of 1 pore-volume/day. During test, pH, EC, Eh and As concentration were measured in the regular term(1 pore-volume). As a result, ZVI and steel refining slag were shown 93%, 62% reduction of As concentration respectively by comparison with untreated soils. Therefore, if ZVI and steel refining slag are used as treatment materials in As-contaminated soils, it is expected that the As concentration in soils is reduced effectively.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1463-1474
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• 2008

In order to investigate stabilization effect and sustainability on As-contaminated farmland soils which were affected the abandoned mine site and stabilized by zerovalent iron(ZVI) and industrial by-products, batch-scale and pilot-scale tests were carried out. In batch tests, ZVI and industrial by-products(blast furnace slag, steel refining slag and oyster shell powder) were used in treatment materials to reduce the As leaching. Industrial by-products were mixed with As-contaminated soils, in the ratio of 1%, 3%, 5% and 7% on the weight base of dried soil. The results of batch-scale tests was shown that the reduction of As concentration was observed in all samples and it was expected that ZVI and steel refining slag were more effective than other treatment materials to stabilize As compounds. In pilot-scale tests, columns were filled with untreated soils and treated soils mixed with ZVI and steel refining slag in the same mixing ratio of 3%. Distilled water was discharged into the columns with the velocity of 0.3 pore volume/day. During the test, pH, EC, Eh and As concentration were measured in the regular term(1pore volume). after six months, pilot-scale tests were retested to investigate sustainability of treatment materials. As a result, It was shown that the leachate from control column was continuously released during the test period and its concentration was greater than $100ug{\cdot}L^{-1}$ which was exceeded the national regulation of water discharged to river or stream ($50ug{\cdot}L^{-1}$). On the other hand, soil treated with ZVI and steel refining slag showed that the concentrations of leachate were lower than national regulation of water discharged to river or stream. Therefore it was expected that ZVI and steel refining slag could be applied to the farmland site as the alternative treatment materials.

• 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.