• Journal of the Korean Chemical Society
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• v.13 no.2
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• pp.141-147
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• 1969

Organophosphorous compounds can be reduced by zinc metal in acidic solution after alkaline hydrolysis. Although phosphates and phosphonates did not evolve any gas, dithioates did evolve hydrogen sulfide and phosphine, thionates and thiolates did evolve only hydrogen sulfide. The evolved gases were qualitatively detected by means of lead acetate and silver nitrate or mercuric bromide papers and determined by spectrophotometrically. The reduction mechanism and analytical method of dithioates were proposed.

• Journal of the Korean GEO-environmental Society
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• v.5 no.2
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• pp.23-31
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• 2004

Trichloroethylene(TCE), Cr(VI), and nitrate removal efficiency of a novel reactive barrier were experimented, and the types of corrosion species that form on the surface of the iron and bentonite as a result of reaction were investigated with Raman spectrophotometer. The reactive barrier is composed of bentonite and zero valent iron(ZVI), and this can substitute conventional geosynthetic clay liners for landfill leachate. Tests were performed in batch reactors for various ZVI content (0, 3, 6, 10, 13, 16, 20, 30, 100 w/w %) and pH. The reduction rates and removal efficiencies of TCE, Cr(VI) and nitrate increase at pH 7 buffered solution. As ZVI content increases, TCE, Cr(VI) and nitrate removal efficiencies increase. From the result of analysis with Raman spectrophotometer, Fe-oxides were observed, which are strong adsorbers of cantaminants. Magnetite can be also beneficial to the long term performance of the iron metal.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.289-295
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• 2017

The International Maritime Organization (IMO) in accordance with the regulations with respect to the combustion gases, such as NOx, SOx generated by the marine engine. The combustion gases must be equipped with a device to reduce emissions from all ships passing through the Baltic SECAs. In Korea, the International Maritime Organization (IMO) and the development of a device for NOx, SOx reduction. Scrubber is used in the ammonia water and the Urea solution in the waste water. The waste water containing ammonium nitrate and ammonium sulfate, react of the NOx and SOx gas. In this study, the recovery of by-product, which contains the waste water was used as an organic solvent extraction method of salting out. Ammonium nitrate and ammonium sulfate, the recovery process. A qualitative analysis of the collected by-product FT-IR analysis. Through the elemental analysis and SEM-EDS, characteristic evaluation was performed with an impurity.

• The Korean Journal of Food And Nutrition
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• v.11 no.4
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• pp.444-451
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• 1998

The changes of amine, nitrate and nitrite nitrogen in yellow corvenia were studied during its processing and storage in order to clarify the precursors of N-nitrosamine(NA) formation in the salted and dried yellow corvenia(Gulbi), prepared y using the different salting method like dry and brine salting by pure and curde salt. As a result, during the processing and storage of Gulbi, DMA and TMA contents were significantly increased in the yellow corvenia. And after 40 days storage the increase rate showed 25.7∼45.7, 3.3∼5.6 times higher than those of 0.3, 2.4mg/kg, respectively, while nitrite contents, during its processing and storage, were scarcely changed in the salted and dried yellow corvenia. During the processing and storage, of Gulbi, DMA and TMA contents were less produced in brine salted and dried yellow corvenia using crude salt than in sample prepared using were scarcely changed in the salted and dried yellow corvenia. During the processing and storage of Gulbi, DMA and TMA contents were less produced in brine salted and dried yellow corvenia using crude salt than in sample prepared using pure salt, while the former were more effective than the latter in inhibiting the production of nitrate and nitrite. Therefore, it was revealed that reduction of NA precursors such as DMA, TMA, nitrate and nitrite were more effective in preparing with the brine salting method than with the dry salting method.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.436-442
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• 2017

This study was conducted to develop a wastewater treatment system to remove organic matter, nitrate nitrogen, and phosphate ion in synthetic wastewater. COD was removed almost 100% by the oxidation reaction of HClO and nitrate nitrogen was reduced to ammonia by electrolysis treatment, but ammonia was reoxidized into nitrate nitrogen by HClO treatment. Ammonia was removed almost 100% by heating evaporation and no ammonia was reoxidized into nitrate by HClO treatment. Phosphate ion could be removed by precipitation treatment by forming metal complex according to pH. Through electrolysis treatment and HClO treatment, removal efficiencies of COD 99.5%, nitrogen 97.3% and phosphorus 91.5% were obtained.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.4
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• pp.337-340
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• 1987

This experiment was conducted on relatively acid sandy loam soil at Choong-ju campus, Kon-kuk University aimed at clarifying the influence of urea and ammonium nitrate on the effect of potassium to Chinese cabbage in soils either limed or unlimed with calcium silicate. The results are summarized as follows: a. Calcium silicate application enhanced cabbage growth and under this condition, the difference in effect of urea and ammonium nitrate can hardly be observed. b. Without calcium silicate application, the response of Chinese cabbage to ammonium nitrate was more distinctive than that to urea. This was partially attributable to the greater use of soil born potassium at ammonium nitrate treatment. c. Added potassium was not only affective in increasing cabbage yield but also contributed in improving quality of cabbage by producing greater edible portion of the cabbage. Such K effect was particularly pronounced on the acid soil where calcium silicate application was neglected. d. Potassium was easily translocated from outer leaves to inner leaves and thus, the concentration of K content in outer leaves played as a limiting factor of cabbage yield. Less than 20 me/100gr of K content in harvested dried outer leaves resulted in a linear reduction of cabbage yield.

• 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.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.1
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• pp.29-35
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• 2013

A dense mixed ionic and electronic conducting ceramic membrane is one of the most promising materials because it can be used for separation of oxygen from the mixture gas. The $ABO_3$ perovskite structure shows high chemical stability at high temperatures under reduction and oxidation atmospheres. $BaCo_{1-x-y}Fe_xZr_yO_{3-{\delta}}$ (BCFZ) was well-known material as high mechanical strength, low thermal conductivity and stability in the high valence state. Glycine Nitrate Process (GNP) is rapid and effective method for powder synthesis using glycine as a fuel and show higher product crystallinity compared to solid state reaction and citrate-EDTA method. BCFZ was fabricated by modified glycine nitrate process. In order to control the burn-up reaction, $NH_4NO_3$ was used as extra nitrate. According to X-Ray Diffraction (XRD) results, BCFZ was single phase regardless of Zr dopants from y=0.1 to 0.3 on B sites. The green compacts were sintered at $1200^{\circ}C$ for 2 hours. Oxygen permeability, methane partial oxidation rate and hydrogen production ability of the membranes were characterized by using Micro Gas Chromatography (Micro GC) under various condition. The high oxygen permeation flux of BCFZ 1-451 was about $1ml{\cdot}cm^{-2}s^{-1}$. Using the humidified Argon gas, BCFZ 1-433 produced hydrogen about $1ml{\cdot}cm^{-2}s^{-1}$.

• Korean Journal of Environmental Agriculture
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• v.28 no.2
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• pp.165-170
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• 2009

The increase in P availability to rice under flooded soil conditions involves the reductive dissolution of iron phosphate and iron (hydr)oxide phosphate. However, since $NO_3^-$ is a more favourable electron acceptor in anaerobic soils than Fe, high$NO_3^-$ loads function as a redox buffer limiting the reduction of Fe. The effect of adding $NO_3^-$ on Fe reduction and P release in paddy soil was investigated. Pot experiment was conducted where $NO_3^-$ was added to flooded soil and changes of redox potential and $Fe_2^+$, $NO_3^-$ and $PO_4^{3-}$ concentrations in soil solution at 10 cm depth were monitored as a function of time. Redox potential decreased with time to -96 mV, but it was temporarily poised at about 330${\sim}$360 mV when $NO_3^-$ was present. Nitrate addition to soil led to reduced release of $Fe_2^+$ and prevented the solubilization of P. Phosphate in pore water began to rise soon after incubation and reached final concentrations about 0.82 mg P/L in the soil without $NO_3^-$ addition. But, in the soil with $NO_3^-$ addition, $PO_4^{3-}$ in pore water was maintained in the range of 0.2${\sim}$0.3 mg P/L. The duration of inhibition in $Fe_2^+$ release was closely related to the presence of $NO_3^-$, and the timing of $PO_4^{3-}$ release was inversely related to the $NO_3^-$ concentration in soil solution. The results suggest that preferential use of $NO_3^-$ as an electron acceptor in anaerobic soil condition can strongly limit Fe reduction and P solubilization.

• Journal of the Korean Chemical Society
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• v.45 no.4
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• pp.395-398
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• 2001