• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.29-34
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• 2009

In this study, a chloride ion probe as a direct measurement for perchlorate reduction was used to determine whether biological perchlorate reduction was inhibited by other electron acceptors ($O_2$ and ${NO_3}^-$) and to investigate competition of electron acceptors for using electron donors. Profiles of chloride production (= perchlorate reduction) in flasks containing perchlorate reducing populations were monitored by a chloride ion probe. Biological reduction of 2 mM perchlorate was inhibited by 2 mM nitrate that chloride production rate was decreased by 30% compared to perchlorate used as the only electron acceptor and chloride production rate was decreased by 70% when acetate was limited. Reduction of 2mM perchlorate was completely inhibited by oxygen at 7~8 mg/L, regardless of acetate excess / limitation.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.11a
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• pp.149-150
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• 2001

질산, 인산, 불산을 페수처리한 슬러지를 가열함에 따라서 아파타이트 결정으로 발달하는 과정을 살펴보면 질산칼슘의 분해에 따라서 아파타이트가 생성되지만 HF는 분해되지 않고, 결정내에 잔류하고 있다는 것을 알 수가 있다. 따라서 $900^{\circ}C$에서 2시간 소성한 아파타이트를 물에 용출시킬 대 HF가 용출되어 나오므로 그 사용에 제한이 되고 있다. 이러한 현상을 방지하고, 양론적인 아파타이트를 제조하기 위하여 인산 이온을 흡착 시키고 $900^{\circ}C$에서 2시간 소성한 결과 불소이온은 대폭적으로 감소되었고, Ca/P의 몰비는 양론적인 1.67에 근접하였고, 이 조건에서 합성한 아파타이트는 중금속의 흡착, 인 및 COD의 흡착, 제거율이 우수하였다.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.2
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• pp.141-149
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• 1985

뿌리에서 흡수된 질소는 대부분이 질산태이온으로 잎의 엽맥까지 도달하나 엽육에서 급격히 환원되어 유기태질소로 동화한다. 잎의 주맥을 통과하여 세맥까지 질산태질소로 이동되며 전질소의 1/2이상의 양까지 다다르나 엽육에서는 전질소함량이 엽맥의 5배까지 증가되어도 질산태질소는 $10^{-2}$ 정도로 급격히 환원되었다. 칼륨은 엽맥까지 질소와 동반 이동하나 엽육에서의 질산태질소환원에 의하여 이동이 차단되는 현상을 보였다. 엽육에 축적된 칼륨은 능금산의 축전을 촉진하였고 질산환원효소의 활성이 왕성하게 일어나는 하위엽에 높은 농도로 축적되었다.

• Journal of the Korean Chemical Society
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• v.28 no.1
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• pp.54-61
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• 1984

The species and equilibrium of molybdate and tungstate have been investigated from the elution behaviors of those in various concentrations of nitric acid and the UV spectra obtained at the various Z values. In higher concentrations than 0.05M nitric acid, the nitarte complex species of $MoO_2(NO_3)_2$ seems to form from the $MoO_2^{2+}$ ions formed by the following equation: $Mo_8O_{26}^{4-} + 20H^+$ ${\rightleftharpoons}$ $8MoO_2^{2+}$ + $10H_2O$. In the case of tungstate, the elution behaviors of tungstate in nitric acid medium are similar to those of perchloric acid, so we think the equilibrium of tungstate existed in perchloric acid could be also existed in nitric acid. These elution behaviors of tungstate are compared with the UV spectra obtained at the various Z values.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.265-265
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• 2010

일반적으로 중금속이나 질산성 질소와 같은 이온성 물질들은 사람의 건강이나 생태계에 좋지 않은 영향을 미칠 수 있다. 이들 오염물질들은 그 종류에 따라 건강에 피해를 주는 정도에 차이가 있지만 안전한 생태환경을 유지하기 위해서는 이들 물질들을 효과적으로 처리할 수 있는 필터가 필요하다. 전극 필터에 최대한 많은 이온들을 흡착시키기 위해서는 전극의 비표면적을 높이는 것이 매우 중요하다. Metal Fiber Filter의 제작과 제작된 Filter의 전기적 특성과 비표면적 향상, 고정성 및 통전성, 축전용량과 전기흡착 및 탈착 경향을 관찰하기 위해 3전극 시스템을 이용하여 Cyclic Voltammetry(CV)와 Chrono-amperometry(CA)를 측정하고 표면의 기공 구조를 관찰하기 위해 주사전자현미경 (SEM;Scanning Electron Microscope)을 이용하여 전극에 생성된 미세 기공의 크기 및 크기 분포를 측정한다. 또한 제작된 Filter 전극을 이용하여 전기장 하에서 수질 속에 있는 질산성이온의 선택적 제거 효율을 측정하여 보고, 측정된 데이터 값을 통해 Metal Fiber Filter의 전기적 특성과 중금속이나 질산성 이온 물질들을 선택적으로 제거할 수 있는 Filter 전극 설계 근거를 제시하고자 한다.

• Journal of Life Science
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• v.7 no.2
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• pp.73-78
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• 1997

Ion exchange performence to remove nitrate in water studied using commercially available strong vase anin exchange resin of $Cl^{-}$ type in the batch reactors. Anion exchange resin was more effective than activated carbon or zeolite. With large resin amount or high temperature or low initial concentration, nitrate removal characteristics for a typical gel-type resin was increased. The curves showed the generally accepted selectivity sequence as ${SO_4}^{2-}>{No_3}^->NO_{2-}>{HCO_3}^-$.

• Journal of Soil and Groundwater Environment
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• v.13 no.4
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• pp.40-53
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• 2008

Groundwater pollution prediction methods have been developed to plan the sustainable groundwater usage and protection from potential pollution in many countries. DRASTIC established by US EPA is the most widely used groundwater vulnerability mapping method. However, the DRASTIC showed limitation in predicting the groundwater contamination because the DRASTIC method is designed to embrace only hydrogeologic factors. Therefore, in this study, three different methods were applied to improve a groundwater pollution prediction method: US EPA DRASTIC, Modified-DRASTIC suggested by Panagopoulos et al. (2006), and LSDG (Land use, Soil drainage, Depth to water, Geology) proposed by Rupert (1999). The Modified-DRASTIC is the modified version of the DRASTIC in terms of the rating scales and the weighting coefficients. The rating scales of each factor were calculated by the statistical comparison of nitrate concentrations in each class using the Wilcoxon rank-sum test; while the weighting coefficients were modified by the statistical correlation of each parameter to nitrate concentrations using the Spearman's rho test. The LSDG is a simple rating method using four factors such as Land use, Soil drainage, Depth to water, and Geology. Classes in each factor are compared by the Wilcoxon rank-sum test which gives a different rating to each class if the nitrate concentration in the class is significantly different. A database of nitrate concentrations in groundwaters from 149 wells was built in Keumsan area. Application of three different methods for assessing the groundwater pollution potential resulted that the prediction which was represented by a correlation (r) between each index and nitrate was improved from the EPA DRASTIC (r = 0.058) to the modified rating (r = 0.245), to the modified rating and weights (r = 0.400), and to the LSDG (r = 0.415), respectively. The LSDG seemed appropriate to predict the groundwater pollution in that it contained land use as a factor of the groundwater pollution sources and the rating of each class was defined by a real pollution nitrate concentration.

• Journal of Food Hygiene and Safety
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• v.18 no.1
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• pp.33-35
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• 2003

This study was performed to investigate the contents of nitrites in 450 meat products in Seoul from Jan. to Dec. in 2002. Nitrites of the samples were determined by Diazoa method. One sample of 450 (0.22%) were detected over 70 ppm in NO$_2$￣ contents. In samples detected over 10ppm, 45.9% (106/231) in hams, 62.5% (70/112) in sausages, 37.5% (6/16) in bacons, and 12.5% (2/16) in crushed meats. Together, these results demonstrated that the processed market meat products must be reinforced to supply for the citizens as safe foods.

• Applied Chemistry for Engineering
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• v.3 no.2
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• pp.312-317
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• 1992

The interaction of dioxouranium(VI) (uranyl) ion with nitrate ion has been studied by $^{17}O$ NMR spectroscopy. The $^{17}O$ resonance of uranyl oxygen atoms(uranyl oxygens hereafter) of $UO_2NO_3{^+}$ was at lower field than that of uranyl ion. The stability constants of $UO_2NO_3{^+}$ were obtained from the variation of $^{17}O$ chemical shifts with nitrate-ion concentration at 5, 15, 25, $35^{\circ}C$ and depend on the ionic strength. Thermodynamic parameters calculated from temperature dependence of the stability constants were as follows : ${\Delta}H=-(27.2{\pm}1.7)kJ\;mol^{-1}$ and ${\Delta}S=-(110{\pm}7)JK^{-1}mol^{-1}$. There was a linear relationship between the enthalpy and entropy for 1:1 complex formation of the uranyl ion with a variety of anionic ligands.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.353-359
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• 1996

Micro plot study was conducted to elucidate the behavior of nitrogen derived from animal manure in soil and to obtain the fundamental information on animal waste management. Soils used in this experiment were sandy loam and loam. Soil water samplers (1m length ceramic cup tube) were installed at 90cm depth of soil to collect the percolate. Fresh and fermented pig manure were applied at the rate of 0, 50, 100 ton per ha. Maize was grown to evaluate the effect of crop on nitrogen behavior through soil profile. Concentration of nitrate nitrogen in percolate increased by application of pig manure. This trend was more obvious at the loam with fermented pig manure than sandy loam with fresh pig manure treatment. The concentration of nitrate nitrogen was lower under the maize cultivation than bare soil condition by 64.6-68.9%. Concentration of Ca, Mg and Na of soil and percolate increased as nitrate nitrogen concentration increased. The equivalent ratio of cation to nitrate nitrogen of percolate was increased by application of pig manure. This result showed that canon leaching was accompanied by nitrate nitrogen. Concentration of nitrate nitrogen of subsurface soil was increased by pig manure application.