• Bulletin of the Korean Chemical Society
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• 제20권9호
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• pp.1067-1072
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• 1999

Structures of unprotonated [(NH3)n+(n = 1-6)] and protonated [NH4+(NH3)n-1(n = 1-6)] ammonia cluster cations have been optimized with ab initio Hartree-Fock (HF) and second-order MФller-Plesset (MP2)/6-31+G ** levels and the harmonic vibrational frequencies have also been evaluated. In unprotonated cluster cations, NH3+ forms as a central core of the first ammonia solvation shell. In protonated cluster cations, NH4+ forms as a central core. In unprotonated dimer and trimer cations, there are two types of isomers (hydrogen-bonded and head-to-head interactions). In both cluster cations, the hydrogen-bonded isomers are more stable. In the hydrogen-bonded dimer cation, the proton transfer reaction takes place from (NH3-HN+H2) to (NH4+-NH2). But in the other unprotonated cluster cations, the proton transfer does not take place. In unprotonated pentamer and hexamer, a NH3+ core has both interactions in a complex. On the other hand, in unprotonated tetramer a core has only the hydrogen-bonded type combined with neutral ammonia molecules. With increasing cluster cation size, the bond lengths [R(NN)] between two nitrogen atoms and the distances [R(N ...H)] of the hydrogen-bond increase reg-ularly. In the calculated infra-red absorption bands for ammonia cluster cations, the characteristic peaks of the bridged NH vibration of the hydrogen-bonded clusters appear near 2500 cm-1 . With increasing size, the peaks shift from 2306 cm-1 to 2780 cm-1 .

• 청정기술
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• 제27권2호
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• pp.168-173
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• 2021

도금폐수의 처리는 폐수의 pH, 중금속 및 시안(CN)함유에 따라 다양하고 복잡한 공정이 적용된다. 이중 시안(CN)의 처리는 차아염소산(NaOCl)을 이용한 알칼리 염소 처리법이 일반적으로 많이 사용되고 있다. 그러나, 암모니아성 질소(NH₃-N)와 시안(CN)이 동시에 함유될 경우 암모니아성 질소(NH₃-N)의 처리를 위해 차아염소산(NaOCl) 이 과다하게 소비되는 문제가 있다. 이러한 문제를 해결하기 위하여 본 연구는 시안(CN)처리에 있어서 1) 알칼리염소법에서 암모니아성 질소(NH₃-N)농도에 따른 차아염소산(NaOCl)의 소모량을 조사하고 2) ferrate (VI)가 시안(CN)을 선택적으로 처리할 수 있는지를 평가하였다. 모의폐수를 이용한 실험결과 알칼리염소법에서는 암모니아성 질소(NH₃-N)농도가 높을수록 시안(CN)의 제거율이 감소하였으며 차아염소산(NaOCl)의 소비량이 암모니아성 질소(NH₃-N) 농도에 따라 선형적으로 증가하였다. Ferrate (VI)를 이용한 시안(CN) 제거에서는 암모니아성 질소(NH₃-N) 농도에 관계없이 시안(CN)의 제거를 확인하였으며 이때 암모니아성 질소(NH₃-N)의 제거율은 낮아 ferrate (VI)가 시안(CN)을 선택적으로 제거함을 확인하였다. Ferrate (VI)의 시안(CN) 제거효율은 pH가 낮을수록 높게 나타났고 ferrate (VI) 주입량에 관계없이 99% 이상을 보였다. 실제 도금폐수에 적용한 결과에서는 ferrate (VI)와 시안(CN)의 투입 몰비 1:1에서 99% 이상의 높은 제거율을 보였으며 이는 화학양론 반응식의 몰비와 일치하는 결과로 모의 폐수와 동일하게 암모니아성 질소(NH₃-N) 및 기타오염물질이 함유된 실제 폐수에서도 선택적으로 시안(CN)을 제거하는 것으로 확인되었다.

• 한국유기농업학회지
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• 제8권2호
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• pp.89-96
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• 2000

To reduce loss of nitrogen and generation of ammonia gas during composting, poultry manure and sawdust were mixed at the equivalent ratio and calcium chloride, fused superphosphate and vermiculite were added. Ammonia and sulfurous gas during composting, and NH4-N and NO3-N contents of composts were periodically measured. With the treatments of 0.5∼3% calcium chloride and 3% fused superphosphate, ammonia and sulfurous gas during composting significantly decreased, and especially generation of gases sharply reduced and a increase of calcium chlorde. Extractable NH4-N content in composts treasted with calcium chloride and fused superphosphate were high but extractable NO3-N markedly decreased. In conclusion, the results suggest that it is necessary the additon of 1∼3% calcium chloride or 3% fused superphosphate to reduce loss of nirogen and generation of offensive odor during composting of poultry manure mixed with sawdust.

• Korean Chemical Engineering Research
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• 제49권2호
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• pp.263-270
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• 2011

본 논문의 목적은 리튬-암모니아 솔루션$(Li(NH_3)_n)$의 실험을 통하여 암모니아물질의 임계점인 $-40^{\circ}C$ 근처에서의 열전특성을 분석하고 이를 증명하는 것이다. 실험 결과 0.58 MPM~1.87 MPM을 갖는 리튬-암모니아 솔루션 $(Li(NH_3)_n)$ 은 온도차$({\Delta}T=0{\sim}15^{\circ}C)$에서 전류가 전압에 비례하는 열전전력을 발생시킨다는 사실을 확인하였다. 본 논문은 열전 물질 개발에 새로운 방향을 제시할 것이다.

• 한국물환경학회지
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• 제22권5호
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• pp.846-850
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• 2006

The biological nutrient removal from domestic wastewater with low C/N ratio is difficult. Therefore, this study was performed to increase influent C/N ratio by ammonia stripping without required carbon source and for improving treatment efficiencies of sewerage by the combination process of ammonia stripping and BNR (StripBNR). The results of this study were summarized as follows. BOD removal efficiencies of BNR and StripBNR were 95.3% and 93.2%, respectively. T-N and T-P removal efficiencies of BNR were 53.3% and 40.8%, respectively. T-N and T-P removal efficiencies of StripBNR were 72.8% and 62.9%, respectively. Concentrations of $NH_3-N$, $NO_2-N$ and $NO_3-N$ at BNR effluent were 0.03 mg/L, 0.08 mg/L and 9.12 mg/L, respectively. On the other hands, concentrations of $NH_3-N$, $NO_2-N$ and $NO_3-N$ at StripBNR effluent were 5.79 mg/L, 0.01 mg/L and 0.14 mg/L, respectively. Consequently, influent C/N ratio of BNR process was increased by ammonia stripping. Removal efficiency of T-N and T-P was improved about 20% by the process of StripBNR.

• Environmental Engineering Research
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• 제13권3호
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• pp.125-130
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• 2008

Free ammonia ($NH_3$-N) inhibition of nitrite-oxidizing bacteria (NOB) has been widely studied for partial nitrification (or nitrite accumulation) and denitrification via nitrite ($NO_2^-$-N) as a low-cost treatment of ammonium containing wastewater. The literature on $NH_3$-N inhibition of NOB, however, shows disagreement about the threshold $NH_3$-N concentration and its degree of inhibition. In order to clarify the confusion, a simple and cheap respirometric method was devised to investigate the effect of free ammonia inhibition of NOB. Sludge samples from an autotrophic nitrifying reactor were exposed to various $NH_3$-N concentrations to measure the maximum specific nitrite oxidation rate ($\hat{K}_{NO}$) using a respirometer. NOB biomass was estimated from the yield values in the literature. Free ammonia inhibition of nitrite oxidizing bacteria was reversible and the specific nitrite oxidation rate ($K_{NO}$) decreased from 0.141 to 0.116, 0.100, 0.097 and 0.081 mg $NO_2^-$-N/mg NOB h, respectively, as the $NH_3$-N concentration increased from 0.0 to 1.0, 4.1, 9.7 and 22.9 mg/L. A nonlinear regression based on the noncompetitive inhibition mode gave an estimate of the Inhibition concentration ($K_I$) of free ammonia to be 21.3 mg $NH_3$-N/L. Previous studies gave $\hat{K}_{NO}$ of Nitrobacter and Nitrospira as 0.120 and 0.032 mg/mg VSS h. The free ammonia concentration which inhibits Nitrobacter was $30{\sim}50\;mg$ $NH_3$-N/L and Nitrospira was inhibited at $0.04{\sim}0.08\;mg$ $NH_3$-N/L. The results support the fact that Nitrobacter is the dominant NOB in the reactor. The variations in the reported values of free ammonia inhibition may be due to the different species of nitrite oxidizers present in the reactors. The respirometric method provides rapid and reliable analysis of the behavior and community of the nitrite oxidizing bacteria.

• 대한환경공학회지
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• 제22권1호
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• pp.53-60
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• 2000

본 연구는 활성탄 유동상 반응조의 암모니아 부하를 $0.1{\sim}7.5kg\;NH_3-N/m^3{\cdot}day$의 범위에서 단계적으로 증가시키면서 암모니아 부하가 질산화 효율 및 아질산성 질소의 축적에 미치는 영향을 파악하기 위하여 수행되었다. 실험 결과, $1.8kg\;NH_3-N/m^3{\cdot}day$ 이상의 암모니아 부하에서는 처리수의 아질산성 질소 농도 및 질산화 효율이 변동하였지만 평균 90%의 질산화효율을 나타내었으며, 유리 암모니아성 질소의 농도가 1 mg/L 이상으로 측정되었던 $1.8kg\;NH_3-N/m^3{\cdot}day$의 암모니아 부하부터 아질산성 질소의 축적이 시작되었다. 아질산성 질소가 축적되었던 기간에는 유입수의 암모니아성 질소 농도와 반응조내의 용존산소 농도 간의 비가 100 이상이거나 처리수 $NH_3-N$ 농도와 반응조 DO 농도 간의 비가 2 이상이었다. 결론적으로, 활성탄 유동상 반응조는 고농도로 암모니아성 질소를 함유하는 폐수의 생물학적 질산화에 효과적이며, 아질산화-탈질에도 유려할 것으로 판단된다.

• 한국초지조사료학회지
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• 제38권3호
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• pp.145-149
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• 2018

The objective of this study was to determine the effect of injection application of pig slurry on ammonia ($NH_3$) and nitrous oxide ($N_2O$) emission from timothy (Phleum pretense L.) sward. The three treatments were applied: 1) only water as a control, 2) pig slurry application by broadcasting, 3) pig slurry application by injection. The pig slurry was applied at a rate of $200kg\;N\;ha^{-1}$. Total $NH_3$ and $N_2O$ emission, expressed as a cumulative amount throughout the measurement time (40 days), was $2.68kg\;NH_3-N\;ha^{-1}$ and $6.58g\;N_2O-N\;ha^{-1}$, respectively, in the control. The injection application of pig slurry decreased total $NH_3$ and $N_2O$ emission by 39.8% and 33.3%, respectively, compared to broadcasting application of pig slurry. The present study clearly showed that injection application exhibited positive roles in reducing N losses through $NH_3$ and $N_2O$ emission.

• 한국물환경학회지
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• 제26권5호
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• pp.732-739
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• 2010

Two combined autothermal thermophilic aerobic digestion (ATAD) and biofilter (BF) systems were operated to treat the piggery wastewater and the ammonia offgas. Experimental results indicated that the organic removal efficiency of ATAD-2, operated with oxygen, was higher than that of ATAD-1, operated with air. The concentration of ammonia in ATAD-2 offgas was higher compared to ATAD-1 offgas, but the total amount of ammonia produced from ATAD-2 was less than that from ATAD-1 due to the lower oxygen flowrate. The ammonia gas produced from both ATAD reactors was successfully removed by the BF. The BF-1, connected with ATAD-1, removed 93% of ammonia at the loading rate of $9.4g\;NH_3-N/m^3/hr$. The BF-2, connected with ATAD-2, removed 95% of ammonia gas at the loading rate of $8.1g\;NH_3-N/m^3/hr$. As the nitrification process continued, pH value of recirculating solution continuously decreased due to the accumulation of nitrate. When the ammonia loading rate was less than $22.7g\;NH_3-N/m^3/h$, the proper replacing cycle of recirculating solution was in the range of 10 to 11 days. Almost 90% of total mass of nitrogen fed into the each BF was confirmed from the mass balance on nitrogen.

• 한국초지조사료학회지
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• 제36권3호
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• pp.199-204
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• 2016

The objective of this study was to determine the effect of nitrification inhibitor dicyandiamide (DCD) and urease inhibitor hydroquinone (HQ) on ammonia ($NH_3$) and nitrous oxide ($N_2O$) emission from pig slurry applied to Timothy (Phleum pretense L.) sward. The daily emission of ammonia ($NH_3$) and nitrous oxide ($N_2O$) was monitored for 9 days in three different treatments; 1) control (only pig slurry application), 2) DCD treatment (pig slurry + DCD), and 3) HQ treatment (pig slurry + HQ). Most $NH_3$ emission occurred after 4~5 days in three treatments. Total $NH_3$ emission, expressed as a cumulative amount throughout the measurement time, was $1.33kg\;N\;ha^{-1}$ in the control. The DCD and HQ treatment decreased total $NH_3$ emission by 16.3% and 25.1%, respectively, compared to the control. Total $N_2O$ emission in the control was $47.1g\;N\;ha^{-1}$. The DCD and HQ treatment resulted in a reduction of 67.9% and 41.8% in total $N_2O$ emission, respectively, compared to the control. The present study clearly indicated that nitrification and urease inhibitor exhibited positive roles in reducing N losses through $NH_3$ and $N_2O$ emission.