• 한국대기환경학회지
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• 제24권5호
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• pp.512-522
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• 2008

Ammonia is a major compound of odor in livestock house. To enhance the performance of ammonia oxidation (decomposition). the gas-liquid, two phase photocatalytic oxidation system was designed and prepared in this study. Commercial P-25 as $TiO_2$ catalyst was used for ammonia decomposition. V/P-25 catalyst prepared by sol gel method was also used for the removal of by-producted $NO_x$ in $NH_3$ oxidation reaction. When $TiO_2$ was used as a photocatalyst, the conversion to $N_2$ in ammonia decomposition reached above 90% until 200hr (The air flow rate of 4L/min with the ammonia concentration up to 25ppm.). However, considerable amounts of NO and $NO_2$ were formed as a result of $NH_3$ oxidation (as a by-product). Therefore, we added Vanadia impregnated $TiO_2$(P-25) catalyst for the removal of $NO_x$ at the end of reaction trail. The results of a pilot-scale operation were successful to achieve the simultaneous removal of $NH_3\;and\;NO_x$ about 81 and 87%, respectively.

• Bulletin of the Korean Chemical Society
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• 제15권5호
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• pp.341-346
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• 1994

The frameworks of $(Cu(NH_3)_3OH^+)_x(NH_4^+)_{12-x}-A{\cdot} zH_2O$ which were prepared by the ion-exchange of zeolite A with ammoniac cupric nitrate solution are more stable than those of $Cu_xNa_{12-2x} -A$ obtained by the ion exchange with aqueous cupric nitrate solution are more stable than those of $Cu_xNa_{12-2x} -A$ obtained by the ion exchange with aqueous cupric nitrate solution. An energetic calculation was made on the relatively stable $(CuOH^+)_2(NH_4^+)_{10}-A{\cdot} 2H_2O$ prepared by the partial evacuation of $(Cu(NH_3)_3OH^+)_2(NH_4^+)_{10}-A{\cdot} zH_2O$. The mean stabilization energies of water, OH-, and $NH_4^+$ ions are -30.23 kcal/mol, -60.24 kcal/mol, and -16.65 kcal/mol, respectively. The results of calculation were discussed in terms of framework stability. The $(Cu(NH_3)_3OH^+)_2(NH_4^+)_{10}-A{\cdot} zH_2O$ zeolite shows two step deammoniation reactions. The first deammoniation around 210 $^{\circ}$C (third DSC peak) was attributed to the decomposition of $[Cu(NH_3)_3OH^+]$ ion and the second one around 380 $^{\circ}$C (fourth DSC peak) was ascribed to the decomposition of $NH_4^+$ ion. The activation energies of the first and second deammoniation reactions were 99.75 kJ/mol and 176.57 kJ/mol, respectively.

• 한국축산시설환경학회지
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• 제4권2호
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• pp.149-160
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• 1998

Hog manure slurry amended with sawdust was composted in pilot-scale reactor vessels using continuous aeration nuder different C/N ratios and pH conditions during composting high rate (decomposition) process. For each material two replicated piles were built and monitored over a period of three weeks. The compost piles had an initial volume of 0.18 ㎥. In this study we evaluated the temperature in compost O2 and CO2 evolution, aeration rate, NH3 concentration etc. and investigated the stability of compost during composting high rate process. According to measured results, while the maximum NH3 concentration during composting high rate process. According to measured results, while the maximum NH3 concentration during composting high rate was in the range of 213 to 412 ppm on 5th day which was near the optimum C/N(22∼24) and pH(7.5∼7.9). And then, the NH3 concentration reduced to between 22∼26 ppm by 13th day. The maximum NH3 concentration for the lower C/N(18∼19) and pH value of 6 reached 574∼1,063 ppm by the 16th through 11th days and the NH3 concentration during continuous aerated composting high rate process, it was more important to manage NH3 gas so that compost odor is reduced.

• 환경위생공학
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• 제11권1호
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• pp.9-15
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• 1996

The purpose of this study was to evaluate the decomposition efficiency of $NH_3$ odor gas using high frequency surface discharge body. The results from this study are as follows; 1, Voltage and frequency of electric elements have effects on removal of $NH_3$ odor. The higher these two elements were set up, the more efficiently deodorizing processing worked. In this experiment, the optimum voltage and frequency applicable were observed around AC 6.0 kVp-p and 24.0 kHz respectively. 2. The temperature, humidity and residence time were observed strong variables for NH$_3$ removal process. Its performance had limits at high temperature and humidity conditions. The longer the residence time continued, the more efficiently deodorization process worked. The experimental results showed that the deodorization was efficiently processed under such conditions as $30.0^{\circ}C$ in temperature, 60rh% in humidity and 0.3 sec in residence time. 3. It was observed that in deodorization experiment, $NH_3$ odor gas was perfectly decomposed under the concentration condition below 15.0ppm. Moreover it was considered as economic and practical in terms of maintenance cost when compared with other deodorization methods.

• 상하수도학회지
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• 제24권6호
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• pp.775-788
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• 2010

The decomposition of 2,4,6-trinitrotoluene (TNT) and the mass balance of nitrogen (N) species as products were investigated in a UV/H2O2system by varying pH, concentrations of $H_2O_2$, and $O_2$. All experiments were conducted in a semi-batch system employing a 50 mL reaction vessel and a coil-type quartz-tube reactor. In contrast with previous studies employing batch mode, TNT decomposition in the semi-batch mode was proportionally enhanced by increasing $H_2O_2$ concentration to 10 mM (0.034%), indicatingthat an inhibitory effect of excess $H_2O_2$on hydroxyl radical (${\cdot}OH$) can be negligible. N compounds are released as $NO_2^-$ in the early stages of the reaction, but $NO_2^-$ is rapidly oxidized to $NO_3^-$ by means of ${\cdot}OH$. $NH_4^+$ was also detected in this study and showed gradually the increase with increasing reaction time. In this study, $NH_4^+$ production can involve the reduction of nitro group of TNT concurrent with the production of $NO_3^-$. Of the N species originating from TNT decomposition, 12 ~ 72% were inorganic forms (i.e. [$NO_3^-$] + [$NO_2^-$] + [$NH_4^+$]). This result suggests that the large remaining N portions indicate that unidentified N compounds can exist.

• Environmental Analysis Health and Toxicology
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• 제6권3_4호
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• pp.133-141
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• 1991

Vermistabilization is the stabilization of organic wastes using earthworms. The worms maintain aerobic conditions in the waste, accelerating and enhancing the biological decomposition of the waste. This study was carried out to find out fundamental factors affecting the performance of the process such as temperature, moisture content and pH condition of nightsoil sludge, and to evaluate the worms excreta (casting) as fertilizer. The results could be summarized as follows; the optimum range of temperature was observed 10~3$0^{\circ}C$ while survival rate of eathworm decreased rapidly at 35$^{\circ}C$ within 6 days and death occurred at 5$^{\circ}C$. Those of moisture content and pH condition were 50~70% and 5~8, respectively. Earthworms were revealed to change the composition of N in nightsoil sludge consisting of$NH_3$-N (71%), $NO_2$-N (2%) and $NO_3$-N (27%) into that $NH_3$-N (24%), $NO_2$-N (1%), $NO_3$-N (75%) in earthworm excreta, respectively The concentrations of NH$_3$and H$_2$S gas in pig manure were reduced by 59.2% and 45.2% in case of mixing pig manure with casting.

• 한국세라믹학회지
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• 제24권5호
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• pp.431-436
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• 1987

High purity Al2O3 has been extracted from serlcite of clayminerals, selicite was treated by H2SO4(2N∼18N) solution, NH4OH treatment(PH8.5∼10.0) and metallic impurities such as Fe were removed by NaOH treatment. The tendency of extraction yield of ${\alpha}$-Al2O3 have been investigated by relating reaction time, acid concentration. Reaction products were analyzed by DT-TGA, chemical analysis and X-ray diffractometer. Prepared ${\alpha}$-Al2O3 power is fired in air at 1400$^{\circ}C$, 1600$^{\circ}C$ 2hr. The results are as follows; 1. The most suitable extracting conditions of ${\alpha}$-Al2O3 from Selicite were N-H2SO4, 120 min acidtreating time. 2. The optimum pH condition was 9.0. 3. Physical properties of sintered Al2O3 bodies were as follows. Relative density is 99%. Water absorption is 0.26%. Rock well hardness is 89.

• 한국재료학회지
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• 제4권8호
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• pp.934-944
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• 1994

수산화물법에 의해 제작된 $\alpha$-stannic acid의 열분해 거동과 $SnO_{2}$분말의 성질에 미치는 잔류염소이온의 영향을 관찰하였다. $SnCl_{4}$와 $NH_{4}$OH 수용액을 중화시켜 $\alpha$-stannic acid침전물을 제작하고 $NH_{4}NO_{3}$수용액으로 세척하였다. 분말내의 잔류 염소이온의 양을 주절하기 위하여 세척정도를 3단계로 조정하였다. 세척후 $100^{\circ}C$에서 건조하고, $500^{\circ}C$ ~ $1100^{\circ}C$에서 하소함으로써 $SnO_{2}$분말을 제조하였다. $\alpha$-stannic acid의열분해 거동ㅇ르 DT-TGA 와 FTIR을 통하여 관찰하고, $SnO_{2}$분말의 조성과 입자크기 및 비표면적을 각각 AES, TEM 및 BET을 통하여 측정하였다. 잔류 염소이온 양이 감소되면, 저온 하소시 일차입자의 상대적 크기가 커지는 반면 고온하소시에는 상대적으로 감소되었ㄷ. 잔류 염소이온의 일부는 $\alpha$-stannic acid내의 격자산소 자리에 위치함으로써, 저온가열시 결정수탈리와 결정화를 지연시키고 또한 고온가열시에는 이의 증발에 의해 산소공공이 생성되어 소결을 촉진시킨다고 제의하였다.

• 한국토양비료학회지
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• 제16권3호
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• pp.223-227
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• 1983

볏짚퇴비(堆肥) 제조시(製造時) 염기치환용량(鹽基置渙容量)이 큰 Zeolite를 첨가(添加)하여 퇴적기간중(堆積期間中) 각종양분(各種養分)의 함량(含量) 및 퇴비성상(堆肥性狀)의 변화(變化)를 조사(調査)한 결과(結果)는 다음과 같다. 1. 퇴비(堆肥) 제조시(製造時) Zeolite를 첨가(添加)하여 줌으로써 무첨가(無添加)에 비(比)하여 부숙온도(腐熟溫度)가 현저(顯著)히 높게 유지(維持)되는 경향(傾向)이었다. 2. 퇴적기간중(堆積期間中) $NH_4-N$, $P_2O_5$ 및 $SiO_2$ 함량(含量)은 Zeolite, 계분(鷄糞), 요소등(尿素等)의 첨가(添加)로 증가(增加)되었으며 부숙(腐熟)이 진전(進展)됨에 따라 증가폭(增加幅)이 더 큰 것으로 보아 Zeolite의 양분류실효과(養分流失效果)과 있었던 것으로 사료(思料)된다. 3. 계분(鷄糞), 요소등(尿素等)과 함께 Zeolite를 첨가(添加)하였을 때 퇴적후(堆積後) 30일(日)에 C/N율(率)이 21.7~25.0 이었고, Zeolite 무첨가시(無添加時)는 준적후(准積後) 60일(日)에야 C/N율(率)이 21.3~24.8로써 속성퇴비제조(速成堆肥製造)와 양분(養分)의 유실방지(流失防止)를 위(爲)한 Zeolite의 효과(效果)가 인정(認定)되었다. 4. 퇴적후(堆積後) 90일(日)의 C/N율(率)과 용적감소율(容積減少率)과는 부(負)의 유의상관(有意相關)이 인정(認定)되었다.

• 한국환경복원기술학회지
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• 제26권2호
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• pp.13-24
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• 2023

Sewage sludge has been widely used as an organic fertilizer in agriculture. However, sewage sludge can cause serious malodor problems resulting from the decomposition of organic compounds in anaerobic conditions. The malodor of sewage sludge mainly occurs due to a low carbon to nitrogen ratio (C/N), high moisture, and low temperature, which are ideal conditions for ammonia emissions. Therefore, in this study, we investigated the reduction of the odor-causing ammonia nitrogen (NH₃-N) in sewage sludge by co-application of microbes and methanol (MeOH). The physico-chemical properties of the municipal sewage sludge showed that the odor was mainly caused by a higher NH₃-N content (2932.2 mg L^-1). Supplementation with MeOH (20%) as a carbon source in the sewage sludge significantly reduced the NH₃-N up to 34.2% by increasing C/N ratio. Furthermore, the sewage sludge was treated with the NH₃-N reducing and plant growth promoting (PGP) bacteria Stenotrophomonas rhizophila SRCM 116907. The treatment with S. rhizophila SRCM 116907 significantly increased the seedling vigor index of Lolium perenne (10.3%) and Chrysanthemum burbankii (42.4%). The findings demonstrate that supplementing sewage sludge with methanol significantly reduces ammonia emissions, thereby mitigating malodor problems. Overall, the study highlights the potential of using a microbial and methanol approach to improve the quality of sewage sludge as an organic fertilizer and promote sustainable agriculture.