• 한국환경과학회지
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• 제20권2호
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• pp.215-222
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• 2011

The adsorption behavior of nitrate nitrogen was investigated from aqueous solution using char prepared from oak chip. The removal rate of nitrate nitrogen was found to be dependent on temperature and it is increased as the temperature increase. Adsorption equilibrium data of nitrate nitrogen on oak char. reasonably fitted Langmuir and Freundlich isotherm models. The adsorption energy obtained from D-R model was 12.5 kJ/mole at $20^{\circ}C$ indicating an ion exchange process as primary adsorption mechanism. Thermodynamic parameters such as ${\Delta}G^o$, ${\Delta}H^o$, and ${\Delta}S^o$ were -23.76 kJ/mole, 26.1 kJ/mole and 89.7 J/K mole at $20^{\circ}C$, respectively, indicated that the nature of nitrate nitrogen adsorption is spontaneous and endothermic.

• 한국토양비료학회지
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• 제33권6호
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• pp.384-392
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• 2000

토양중 질산태 질소 함량이 $14{\sim}225mg\;kg^{-1}$의 범위를 갖는 시설재배지 9개 토양에서 배추를 공시작물로 하여 무비구, 3요소 표준시비량의 50%구, 100%구 및 150%구의 4개 시비수준에서 포트재배로 수량반응, 비료효과 및 시비효율 등을 검토하였다. 무비구 배추 건물중과 토양의 질산태 질소 함량은 유의성 있는 정의 상관을 나타냈고 시비구와 무비구의 건물중, 질소흡수량 및 질산태 질소흡수량의 차이로 평가한 비료효과 및 시비효율과는 유의성 있는 부의 상관을 보였다. 질산태 질소함량에 따른 시비수준별 건물중 반응의 관계로부터 표준시비량이 적용되는 질산태 질소의 하한기준은 $50mg\;kg^{-1}$ 미만으로 추정되었고, 질산태질소 함량과 비료효과 및 시비효율과의 회귀관계로부터 평가된 무비 재배를 위한 질산태 질소 함량은 $200mg\;kg^{-1}$ 이상으로 추정되었다. 따라서 시설재배지 토양중 질산태 질소 함량 $50mg\;kg^{-1}$에서 $200mg\;kg^{-1}$ 범위는 질소 표준시비량에 대한 비율로서 추천식은 $Y=-0.6667{\chi}+133.33$ 이었다 (Y:질소 표준시비량에 대한 %, ${\chi}$: 시험전 토양의 $NO_3-Nmg\;kg^{-1}$).

• 한국초지조사료학회지
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• 제19권1호
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• pp.81-88
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• 1999

본 시험은 질소비료의 다용(多用)이 사초내의 질산염 함량, 강우에 의한 사초내의 질산염 함량, 그리고 하루 중 사초내의 질산염 함량의 차이를 조사하여 반추가축의 질산염 중독 발생 예방과 적정 질소시비수준을 구명하기 위하여 수단그라스계 교잡종 중 Xtragraze II 1번초를 공시하여 1995년 6월부터 9월까지 익산대학 동물사육장 시험포에서 실시하였다. 시비수준은 ha당 연간 질소 200kg, 400kg 및 600kg으로 하고, 인산과 칼리비료는 200kg씩 사용하였으며 얻어진 결과는 다음과 같다. 질산태질소 함량은 생육시기의 진전에 따라 감소하였는데, 200kg구에서는 신장기초까지, 그리고 400kg 이상에서는 전생육기간 동안 중독위험수준을 초과하였다. 강우 후 사초의 질산태질소 함량은 성장기에는 일시적으로 증가하는 경향이 있지만, 생육말기나 출수기 이후에는 거의 영향이 없었다. 사초의 하루 중 질산태질소 함량은 오전이 오후보다 비교적 더 높은 경향이었다. 질산염중독으로부터 비교적 안전한 질소시비수준은 $200kg{\cdot}N/ha/year$ 이하로 나타났다.

• 한국대기환경학회지
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• 제2권1호
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• pp.33-39
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• 1986

Particulate matter was collected by Andersen Air Sampler in the Seoul area during February-October, 1985, in order to investigate size distribution of sulfate and nitrate in aerosol, and conversion of sulfur dioxide to sulfate and that of nitrogen dioxide to nitrate. The size distribution of sulfate and nitrate had fine mode. The ratio of fine sulfate to total sulfate in aerosol and that of fine nitrate to total nitrate showed between 54.6% and 86%, and 55.7% and 95%, respectively, which presumably originated from gaseous reaction of sulfur dioxide and nitrogen dioxide in the atmosphere.

• 상하수도학회지
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• 제26권4호
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• pp.579-589
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• 2012

To reduce extensive energy costs of the internal recycling for the purpose of denitrification in the advanced wastewater treatment, a post-treatment process using an electro-coagulation to treat nitrate in the secondary effluents is evaluated in this study. Removals of phosphorus and organics in the secondary effluents by the electro-coagulation were also evaluated to propose an alternative advanced wastewatert treatment process. A series of experiments of the electro-coagulation were carried out with the following 4 different samples: synthetic solution containing nitrate only, synthetic solution containing nitrate as well as phosphorus, secondary effluents from activated sludge cultivated in laboratory, and secondary effluents from real wastewater treatment plants. Removals of nitrate and phosphorus in the synthetic solution were 30 and 97 % respectively, which verified the feasibility of the process. Removals of nitrate, phosphorus and COD in the secondary effluents from the cultivated sludge in laboratory were 49, 90 and 19 % respectively. Removal efficiency of the total nitrogen, nitrrate, phosphorus and COD in the secondary effluent from real wastewater treatment plant were 50, 61, 98 and 80 % respectively. The removal of the total nitrogen was less than the nitrate as expected, which is due to the formation of ammonia nitrogen in the cathode. But the proposed scheme could be an energy saving and alternative process for the advanced wastewater treatment if further studies for the process optimization are carried out.

• Journal of Plant Biology
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• 제34권4호
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• pp.253-260
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• 1991

Spirodela polyrhiza and Lemna aequinoctialis often occurred at the sites of high ammonium concentration and at the sites of high nitrate concentration, respectively. We investigated the different distribution between two species in relation to the type of nitrogen sources and their concentrations. Our experiments showed that L. aequinoctialis grew faster than S. polyrhiza in nitrate media with lower than 15 mM concentration. The nitrate uptake was also faster in L. aequinoctialis than in S. polyrhiza. However, neither differences in growth nor in uptake patterns between these two species were observed in ammonium media. Glutamine synthetase (GS), glutamate dehydrogenase (GDH) and glutamate synthetase (GOGAT) activities were higher in L. aequinoctialis. In particular, nitrate reductase activity (NRA) in L. aequinoctialis was 12.1 times as high as that in S. polyrhiza. These results showed that the two species responded varyingly to the types of nitrogen sources and their concentrations. Therefore, the difference in geographic distribution between the two species appeared to reflect the interspecific differences in enzyme activities and, subsequently, nitrogen absorption abilities.

• Asian-Australasian Journal of Animal Sciences
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• 제22권4호
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• pp.542-549
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• 2009

An in vitro study was conducted to determine the effect of nitrate-nitrogen used as a sole dietary nitrogen source on ruminal fermentation characteristics and microbial nitrogen (MN) synthesis. Three treatment diets were formulated with different nitrogen sources to contain 13% CP and termed i) nitrate-N diet (NND), ii) urea-N diet (UND), used as negative control, and iii) tryptone-N diet (TND), used as positive control. The results of 24-h incubations showed that nitrate-N disappeared to background concentrations and was not detectable in microbial cells. The NND treatment decreased net $CH_4$ production, but also decreased net $CO_2$ production and increased net $H_2$ production. Total VFA concentration was lower (p<0.05) for NND than TND. Suppression of $CO_2$ production and total VFA concentration may be linked to increased concentration of $H_2$. The MN synthesis was greater (p<0.001) for NND than UND or TND (5.74 vs. 3.31 or 3.34 mg/40 ml, respectively). Nitrate addition diminished methane production as expected, but also increased MN synthesis.

• 한국초지조사료학회지
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• 제42권3호
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• pp.176-182
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• 2022

The aim of this study was to investigate dry matter productivity and nitrate nitrogen content in the growth stages of barnyard millet (Echinochloa esculenta) cultivated for feed, which was treated with different nitrogen fertilization levels. An early variety of barnyard millet (cv. Shirohie) was used for the test, and the different treatments with nitrogen fertilizer were as follows: 50% (N-40 kg/ha, T1), 100% (N-80 kg/ha, reference amount, T2), 150% (N-120 kg/ha, T3), 200% (N- 160 kg/ha, T4), 250% (N-200 kg/ha, T5), and 300% (N-240 kg/ha, T6). Sowing was done on May 13, 2021 and plants were harvested for four stage; vegetative stage, elongation stage, heading stage, and milk stage. The length of the millet increased significantly as the amount of nitrogen fertilization increased during the harvest period (p<0.05), but the difference was insignificant during the milk stage (p>0.05). Moreover, barnyard millet dry matter yield increased significantly as the levels of nitrogen fertilization increased (p<0.05), but there was no significant difference in dry matter yield among nitrogen fertilization levels during the heading stage (p>0.05). Chlorophyll also was significantly higher in T5 (250%) at all harvesting times, whereas nitrate nitrogen content was highest at the vegetative stage, gradually decreased as growth progressed, and lowest at the milk stage. Finally, as the nitrogen fertilization levels increased, the nitrate nitrogen content was significantly higher in all treatment groups (p<0.05). Therefore, our results suggest that the most appropriate nitrogen fertilizer levels is between 150%-200%, considering the dry matter yield, feed ingredients and nitrate nitrogen content in barnyard millet for feed.

• 한국응용과학기술학회지
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• 제34권3호
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• pp.487-494
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• 2017

질산성 질소는 수용액에서 상당히 안정하게 존재하기 때문에 제거하는 데에 있어 상당한 기술이 요구된다. 또한 저 농도의 질산성 질소는 쉽게 제거되는 반면 고농도 질산성 질소는 제거하기가 힘들다. 따라서 본 연구에서는 직경 3mm 정도의 아연 ball을 이용하여 고농도의 질산성 질소를 기체 질소의 형태로 제거하는 것을 목적으로 하였고, 다양한 반응조건에서 질산성 질소의 제거 특성을 실험하였다. 본 연구의 결과로 아연 ball을 사용하여 연속식 처리를 통한 질산성 질소의 처리효율은 약 80%정도 되었다. 하지만 폐수를 수소이온농도 2 정도의 산성 분위기로 유지시켜야하고 처리된 폐수를 중화 처리하여 방류시켜야하는 등의 문제점은 상존하고 있다.

• Journal of Applied Biological Chemistry
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• 제42권4호
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• pp.186-190
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• 1999

Isotope ratio ($^{15}N/^{14}N$) and nitrate-nitrogen concentration in groundwater were measured to investigate the effect of chemical fertilizer and livestock manure on temporal variations in nitrate-nitrogen concentration and to estimate the contribution of fertilizer and manure to groundwater contamination by nitrate. Four study wells from a rural area in Kyonggi province were selected. One well was located on an upper site from a livestock feedlot, and the others were situated at lower sites from the feedlot. The ${\delta}^{15}N$ values were analyzed by a stable isotope ratio mass spectrometer (Micromass, VG Optima IRMS). Reproducibility of the method and precision of the mass spectrometer were below 1.0 and 0.1‰, respectively Even though study wells were located at the same area, nitrate-nitrogen concentrations and ${\delta}^{15}N$ values differed and fluctuated during the sampling period. The ${\delta}^{15}N$ values of well located at upper site from the feedlot were extremely variable (-1.48~20.80‰). The ranges of ${\delta}^{15}N$ value of three wells situated at lower sites from the feedlot were 11.83~20.73 (ave. 16.11), 8.90~11.73 (ave.11.01), and 5.29~12.73‰ (ave. 8.21‰) with increasing distance from the feedlot. The average values of contribution proportion of nitrogen derived from livestock manure to nitrate-nitrogen in groundwater were 79% for the well closet to the feedlot, 44% for the well most distant from the feedlot, and 56% for the well in between the two wells.