• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.253-258
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• 2010

In the field of the $CO_2$ absorption process using aqueous ammonia, the effects of regeneration pressure and temperature on $CO_2$ absorption performances of the aqueous ammonia were investigated. The absorbents were prepared by dissolving ammonium carbonate solid in water to grant the resulted solution 0.5 $CO_2$ loading ($mol\;CO_2/mol\;NH_3$) and various ammonia concentration (14, 20, 26 and 32 wt%). As-prepared absorbents were regenerated at high pressure and temperature (over $120^{\circ}C$ and 6 bar) before the absorption test. The absorption test was carried out by injecting the simulated gas that contains 12 vol% of $CO_2$ into a bubbling reactor. The introduction of 26 wt% of the ammonia concentration for $CO_2$ absorption test resulted in the higher absorption capacities than other experimental conditions. In particular, when the absorbents with 26 wt% of the ammonia were regenerated at $150^{\circ}C$ and 14 bar, the highest absorption capacity, $45ml\;CO_2/g$, was obtained. According to the analysis of absorbents using acid-base titration, the ammonia loss during the regeneration of the absorbents with a fixed ammonia concentration decreased as the regeneration pressure increased, while it increased as the regeneration temperature increased. In the condition of fixed regeneration pressure and temperature, as expected, the ammonia loss increased as the ammonia concentration increased. The measured $CO_2$ loadings and ammonia concentrations of absorbents were compared to the values calculated by Electrolyte NRTL model in Aspen Plus.

• Journal of the Korean Chemical Society
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• v.10 no.2
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• pp.54-58
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• 1966

By means of aqueous oxidation in ammonia solution, metallic zinc and sulfur in marmatite were leached. In this study, it was found that the concentration of ammonia was extremely influenced on the oxidation ratio of Zn and S, and the more the leaching temperature was low, the more their leaching ratio was decreased. The maximum leaching ratio to the contents in marmatite was obtained at the following conditions. Particle size 270 mesh above, $NH_3$ conc, 25%, Press. 4.2 kg/$cm_2$, Temp.$ 60 ^{\circ}C$, Time 20hrs. Leaching ratio; Zn 55% and S 50%.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.23-28
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• 1997

The adsorption characteristics of ammonia-Cu(II) complex on activated carbon were studied. Firstly, the specific surface area of the activated carbon was measured by using the BET adsorption apparatus. Secondly, the characteristics of the removal copper(II) ion from aqueous ammonia solution by forming a complex with ammonia and then by the adsorption of the complex on the activated carbon were studied. It was found that the specific surface area increases with decreasing the mesh number of the activated carbon, and the optimum pH for the adsorption of the Cu(II) ion on she activated carbon was found to be approximately 6. It was also found that the adsorbed Cu(II)-ammonia complexes on the activated carbon in the aqueous ammonia solution have two types, depending on the concentration of the solution ; i.e. $[Cu(NH_3){_2}]^{2+}$and $[Cu(NH_3){_3}]^{2+}$ for $2.25{\times}10^{-4}(mol/{\ell})$and $2.25{\times}10^{-3}(mol/{\ell})$, respectively.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.372-376
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• 2015

The experiment was performed using the cleaning precipitator To investigate the absorption efficiency of the $SO_X/NO_X$ of the aqueous ammonia solution. Concentration of the cleaning liquid is 0.1, 0.5, and 1.0% with increasing absorption efficiency has improved. However, the reaction shown only a difference in time. Absorption efficiency has improved in accordance with the gas residence time. When the direction of the same gas and the cleaning liquid is determined that there is the effect of increasing the residence time. The relative impact of $SO_X$ and $NO_X$ is this likely to react slower than $SO_X/NO_X$. The yield is determined to require adjustment of the cleaning dust collector according to the concentration of the next gas.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.1-7
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• 2001

Ammonia is used in the manufacture of fertilizers, refrigerants, stabilizers and many household cleaning agents. These wide applications resulted in ammonia contamination in water. Ammonia can be removed from water by physical, biological, and chemical methods. Ozonation is effictive in the treatment of water with low concentration of ammonia. This study is undertaken to provide kinetic data for the ozonation of ammonia with or without hydrogen peroxide. The results were as follows; The destruction rate of ammonia increased gradually with the influent hydrogen peroxide concentration up to 0.23 mM and inhibited in the range of 0.23~11.4mM, and the maximum removal rate of ammonia achieved at 0.23mM of hydrogen peroxide, and the overall kinetics was first order. The combination effect of hydrogen and ozone to oxide ammonia in aqueous solution was better than ozone alone. The reacted ammonia was converted completely to nitrate ion.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.805-808
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• 2003

Fundamental ideas of the free energy gradient method are briefly reviewed with three applications: the stable structures of glycine and ammonia-water molecule pair in aqueous solution and the transition state (TS) structure of a Menshutkin reaction $NH_3 + CH_3Cl → CH_3NH_3^+ + Cl^-$ in aqueous solution, which is the first example of full TS optimization of all internal degrees of freedom.

• Journal of the Korean Ceramic Society
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• v.28 no.12
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• pp.975-980
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• 1991

Chelated titanium alkoxides are hydrolysed showly and stable enough to prepare multicomponent gels of titania without its precipitation due to the fast hydrolysis of Ti alkoxide. The alkoxy groups of chelated titanium alkoxide are hydrolysed as fast as that of titanium alkoxide but the chelating groups are stable even in aqueous solution. The chelating groups showed different rates of hydrolysis in aqueous ammonia solution and water added one. Those rates were monitored with UV-VIS spectrophotometer by using their unique absorption bands before and after hydrolysis.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.6
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• pp.674-681
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• 2008

Silver as a metal catalyst has been used to remove odorous compounds. In this study, silver particles in nano sizes ($5{\sim}30nm$) were prepared on the surface of $NaHCO_3$, the supporting material, using a sputtering method. The silver nano-particles were dispersed by dissolving $Ag-NaHCO_3$ into water, and the dispersed silver nano-particles in the aqueous phase was applied to remove inorganic odor compounds, $NH_3$ and ${H_2}O$, in a scrubbing reactor. Since ammonia has high solubility, it was removed from the gas phase even by spraying water in the scrubber. However, the concentration of nitrate (${NO_3}^-$) ion increased only in the silver nano-particle solution, implying that the silver nano-particles oxidized ammonia. Hydrogen sulfide in the gas phase was rapidly removed by the silver nano-particles, and the concentration of sulfate (${SO_4}^{2-}$) ion increased with time due to the oxidation reaction by silver. As a result, the silver nano-particles in the aqueous solution can be successfully applied to remove odorous compounds without adding additional energy sources and producing any harmful byproducts.

• Resources Recycling
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• v.12 no.3
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• pp.31-37
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• 2003

A study on the characteristics of ammonia desorption from aqueous solutions has been performed by air stripping as the first stage of ammonia recycling for the preparation of ammonium sulfate from it. For air stripping experiments, a stripping column made with acrylic tube of 40 mm diameter was employed and compressed air was injected into solutions through air sparger equipped at the bottom of stripping column. As a result of experiments, the stripping efficiency was increased with the aqueous pH and it was found that the appropriate pH for air stripping of ammonia was between pH 10 and 12. As far as the effect of air flow rate on ammonia stripping was concerned, ammonia stripping was not proportional to the air flow rate although it was affected by the air flow rate to some extent. Moreover, when more than 20 cm of water height was maintained, total ammonia desorbed from solution was not varied with the water height. Stripping temperature was also found to play an important role in ammonia desorption and about 90fo of initial ammonia was desorbed in 14 hours at pH 12.8 and at $60^{\circ}C$ Finally, it was believed that stripping temperature as well as the aqueous pH was one of the most important factors in air stripping of ammonia.

• Journal of Information Display
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• v.13 no.3
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• pp.107-111
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• 2012

An almost pure phase of $Ba_3Si_6O_{12}N_2$ doped with $Eu^{2+}$ was successfully synthesized through the ammonia nitridation of an oxide precursor prepared through an aqueous-solution method, using propylene- glycol-modified silane. The emission peak intensity of the obtained $Ba_3Si_6O_{12}N_2:Eu^{2+}$ was -2.2 times higher than that of the sample prepared through a solid-state reaction method.