• Journal of Korean Society for Atmospheric Environment
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• v.24 no.5
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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.

• Journal of Korean Society on Water Environment
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• v.26 no.5
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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.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.211-216
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• 2000

In this paper, experimental investigations were carried out to remove NOx, SOx simultaneously from a simulated combustion flue gas [$NO(0.02%)-SO_2(0.08%)-CO_2-Air-N_2$] by using a pulse corona induced plasma chemical processing. Discharge domain of wire-cylindrical plasma reactor was separated from a gas flow duct to avoid unstable discharge by aerosol particle deposited on discharge electrode and grounded electrode. The NOx, SOx removal was experimentally investigated by a reaction induced to ammonium nitrate, ammonium sulfate using a low price of aqueous NaOH solution and a small quantity of ammonia. Volume percentage of aqueous NaOH solution used was 20% and $N_2$ flow rate was $2.5{\ell}/min$ for bubbling aqueous NaOH solution. Ammonia gas(l4.82%) balanced by argon was diluted by air and was introduced to a main simulated flue gas duct through $NH_3$ injection system which was in downstream of reactor. The $NH_3$ molecular ratio(MR) was determined based on [$NH_3$] and [$NO+SO_2$]. MR is 1.5. The NOx removal rates increased in the order of DC, AC and pulse, but SOx removal rates was not significantly effected by source of electricity. The NOx removal rate slightly decreased with increasing initial concentration. but SOx removal rate was not significantly affected by initial concentration. The NOx, SOx removal rates decreased with increasing gas flow rate.

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.258-263
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• 2007

Ammonia water was investigated as a new absorbent of the chemical absorption process for the removal of $CO_2$ in flue gas. The suitable range of ammonia water concentration and $CO_2$ loading ($mol\;CO_2/mol\;NH_3$) were decided in the point of view of $CO_2$ absorption capacity and $NH_4HCO_3$ precipitation. The absorption capacity of $CO_2$ and the precipitation of $NH_4HCO_3$ in liquid phase were calculated by the Pitzer model for electrolyte solution. The $CO_2$ absorption capacity of the ammonia water over $5\;molNH_3/kgH_2O$ was higher than that of conventional amine absorbent. The $CO_2$ loadings where precipitation occurred were decided at various absorbent concentrations. Theses values were higher than 0.5 in the concentration range of $5-14\;molNH_3/kgH_2O$ at 293, 313 K. The absorber for the removal of $CO_2$ in flue gas could be operated without $NH_4HCO_3$ precipitation by using high concentration of ammonia water below these $CO_2$ loading values. The optimum temperature of the ammonia water absorbent for removal of $CO_2$ in flue gas was 297-312 K depending on the concentration of ammonia water.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.2
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• pp.199-207
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• 2015

Solid materials of ammonia sources with SCR have been considered for the application of lean NOx reduction in automobile industry, to overcome complex problems of liquid urea based SCR. These solid materials produce ammonia gas directly with proper heating and can be packaged by compact size, because of high volumetric ammonia density. Among ammonium salts and metal ammine chlorides, calcium ammine chloride was focused on this paper due to low decomposition temperature. In order to make calcium ammine chloride in lab-scale, simple reactor and glove box was designed and built with ammonium gas tank, regulator, and sensors. Basic test conditions of charging ammonia gas to anhydrous calcium chloride are chosen from equilibrium vapor pressure by Van't Hoff plot based on thermodynamic properties of materials. Synthetic method of calcium ammine chloride were studied for different durations, temperatures, and pressures with proper ammonia gas charged, as a respect of ammonia gas adsorption rate(%) from simple weight calculations which were confirmed by IC. Also, lab-made calcium ammine chloride were analyzed by TGA and DSC to clarify decomposition step in the equations of chemical reaction. To understand material characteristics for lab-made calcium ammine chloride, DA, XRD and FT-IR analysis were performed with published data of literature. From analytical results, water content in lab-made calcium ammine chloride can be discovered and new test procedures of water removal were proposed.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.45-56
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• 1999

A biofilter was established to remove the ammonia, which is representative nitrogen-contained malodorous gas. in a compost factory. Removal efficiency of ammonia and hydrogen sulfide also was investigated. A quantity of malodor gas produced in a compost factory was affected greatly by the weather. compost states and working condition of a fertilizing mixer, and the produced gas concentrations doubled by above various parameters. By operating a water scrubbing system for removing water-soluble malodorous gases effectively. we could improve the removal efficiency over three times. We investigated long-term stability of biofilter under continuous gas flow(SV=500h-1) for 100 days. The results showed 30 days of microbial retention time. After the days, deodorization efficiency of biofilter was kept steady state. and the removal efficiency was kept over 95% for ammonia and 97% for hydrogen so]fide. respectively. The electric consumption of the biofilter, which could treat malodorous gas of 100$\textrm{m}^3$/min, applied in the compost factory was evaluated about 80u0day and water consumption was 80~100$\ell$/day. These results concluded that the biofilter is a excellent deodorization technology as well as cost-effective for removing malodorous gas produced in a compost factory.

• Journal of Climate Change Research
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• v.8 no.1
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• pp.51-56
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• 2017

The objective of the research project is to develop the hybrid deodorizer for the removal of residual harmful gases generating during pretreatment process of biogas. This hybrid deodorizer is capable of treating harmful gases that contains hydrogen sulfide ($H_2S$), ammonia ($NH_3$) and other odor substances. This hybrid deodorizer reduced the hydrogen sulfide content from approximately 150~200 ppm to less than 16 ppm. These residual harmful gases were effectively removed in the effluent, achieving up to 97% removal of $H_2S$ and 94% removal of $NH_3$ after treatment using hybrid deodorizer.

• Korean Journal of Environmental Agriculture
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• v.34 no.2
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• pp.134-138
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• 2015

BACKGROUND: In recent years, several researchers have focused on odour control methods to remove the harmful chemicals from chemical accidents and incidents. The present work deals with the system development of the hazardous. METHODS AND RESULTS: For on-site removal of hazardous gaseous materials from chemical accidents, mobile vortex wet scrubber was designed with water vortex process to absorb the gas into the water. The efficiency of the mobile vortex wet scrubber was evaluated using water spray and 25% ammonia solution. The inlet air velocity (gas flow rate) was according to the damper angle installed within the hood and with increase of gas flow rate, consequently the absorption efficiency was markedly decreased. In particular, when 25% ammonia solution was exposed to the hood inlet for 30 min, the water pH within the scrubber was changed from 7 to 12. Interestingly, although the removal efficiency of ammonia gas exhibited approximately 80% for 5 min, its efficiency in 10 min showed the greatest decrease with 18%. Therefore, our results suggest that the ammonia gas may be absorbed with the driving force of scrubbing water in water vortex process of this scrubber. CONCLUSION: When chemical accidents are occurred, the designed compact scrubber may be utilized as effective tool regarding removal of ammonia gas and other volatile organic compounds in the scene of an accident.

• Journal of Environmental Science International
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• v.1 no.2
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• pp.105.1-113
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• 1992

The present study was performed to develop the removal system of the offensive gases, including hydrogen sulfide of acid gas, ammonia or amice of base gas, from the nightsoil treatment plant. In order to remove the offensive gases, the Fe-EDTA system liquid phase catalytic oxidation method with the bubble lift column reactor was employed. From the results obtained, it was confirmed that the offensive gases can be deodorized simultaneously and also hydrogen sulfide of acid gas, ammonia of base gas completely removed at pH 6.45. In addition, as input gases feed rate the efficiency of acid gas did not change but the efficiency of base gases decreased to approximately 90 % at pH 6, 0. From the result of particle size analyzer, it was found that the particle sizes including sulfur and other impurites grew up to $21{\mu}m$ over 72hour reaction time.

• Journal of Environmental Health Sciences
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• v.33 no.4
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• pp.293-298
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• 2007

The microorganism for ammonia gas removal was isolated from composting product. This was identified as Brevundimonas diminuta by morphological, biochemical characteristics study and 16S rDNA sequence analysis. Optimal incubation temperature for cell growth and oxidizing ability of $NH_4-N$ was $30^{\circ}C$ and optimal initial pH was 7. Glucose affected the growth of cell and the removal of $NH4^+$. The growth rate of the isolates were increased when grown in the presence of 0.05-1%(w/v) glucose in the selective medium and lurker increases in glucose concentration to 2% caused significant decreases in the cell growth and oxidizing ability of $NH4^+$.