• Clean Technology
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• v.27 no.4
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• pp.341-349
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• 2021

In combustion facilities, the nitrogen and sulfur in fossil fuels react with oxygen to generate air pollutants such as nitrogen oxides (NO_X) and sulfur oxides (SO_X), which are harmful to the human body and cause environmental pollution. There are regulations worldwide to reduce NO_X and SO_X, and various technologies are being applied to meet these regulations. There are commercialized methods to reduce NO_X and SO_X emissions such as selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and wet flue gas desulfurization (WFGD), but due to the disadvantages of these methods, many studies have been conducted to simultaneously remove NO_X and SO_X. However, even in the NO_X and SO_X simultaneous removal methods, there are problems with wastewater generation due to oxidants and absorbents, costs incurred due to the use of catalysts and electrolysis to activate specific oxidants, and the harmfulness of gas oxidants themselves. Therefore, in this research, microbubbles generated in a high-pressure disperser and reducing agents were used to reduce costs and facilitate wastewater treatment in order to compensate for the shortcomings of the NO_X, SO_X simultaneous treatment method. It was confirmed through image processing and ESR (electron spin resonance) analysis that the disperser generates real microbubbles. NO_X and SO_X removal tests according to temperature were also conducted using only microbubbles. In addition, the removal efficiencies of NO_X and SO_X are about 75% and 99% using a reducing agent and microbubbles to reduce wastewater. When a small amount of oxidizing agent was added to this microbubble system, both NO_X and SO_X removal rates achieved 99% or more. Based on these findings, it is expected that this suggested method will contribute to solving the cost and environmental problems associated with the wet oxidation removal method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.157-158
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• 2020

The present study examined the effectiveness of textile fabrics coated with nano-pore materials on removing the nitrogen oxide (NO_X) and sulfur oxide (SO_X) in the atmospheric environment. The tested approach is favorable for absorbing NO_X and SO_X, even under the washing condition.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.5
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• pp.659-667
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• 2018

$NO_x$ and $SO_2$ are mainly generated in the combustion of fossil fuels, and they cause secondary aerosol formation and acid rain in the atmosphere. Many studies have been conducted on the wet scrubbing process which can simultaneously reduce $NO_x$ and $SO_2$ at relatively low temperature. In this study, we conducted an experimental study on wet scrubbing by using NaOH solution. Especially, this study focuses on $NO_x$ and $SO_2$ removal characteristics by varying $NO_2/NO_x$ ratio and $SO_2$ concentration.

• Journal of the Korean Applied Science and Technology
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• v.31 no.1
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• pp.159-166
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• 2014

In recent years, researchers have put a considerable effort to decrease the emission of harmful gaseous pollutants to the atmosphere. In order to remove simultaneously $SO_2$ and $NO_X$ from the flue gas of small and medium-sized ship, we designed minimal wet scrubber inside a compact multistage modular system. In this study we proceed experiment of elemental technology at each stage of the scrubber. The each stage is oxidation of NO which is the main component of $NO_X$, and removal of $SO_2$, respectively. $NaClO_2$ was used to oxidize NO gas, and NaOH was used to remove $SO_2$ gas. The maximum NO conversion efficiency and the $SO_2$ removal efficiency are both indicate 100%.

• Journal of Industrial Technology
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• v.18
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• pp.249-258
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• 1998

In this paper, we investigated the post-combustion removal of nitrogen oxide($NO_x$) and sulfur oxide($SO_x$) which is based on the gas to particle conversion process by the pulsed corona discharge. Under normal pressure, the pulsed corona discharge produces the energetic free electrons which dissociate gas molecules to form the active radicals. These radicals cause the chemical reactions that convert $SO_x$ and $NO_x$ into acid mists and these mists react with $NH_3$ to form solid particles. Those particles can be removed from the gas stream by conventional devices such as electrostatic precipitator or bag filter. The reactor geometry was coaxial with an inner wire discharge electrode and an outer ground electrode wrapped on a glass tube. The simulated flue gas with $SO_x$ and $NO_x$ was used in the experiment. The corona discharge reactor was more efficient in removing $SO_x$ and $NO_x$ by adding $NH_3$ and $H_2O$ in the gas stream. We also measured the removal efficiency of $SO_x$ and $NO_x$ in a cylinder type corona discharge reactor and obtained more than 90 % of removal efficiency in these experimental conditions. The effects of process variables such as the inlet concentrations of $SO_x$, $NH_3$ and $H_2O$, residence time, pulse frequencies and applied voltages were investigated.

• Korean Journal of Crystallography
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• v.16 no.2
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• pp.75-80
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• 2005

[ $LiK_{1-x}Rb_{x}SO_{4}(x=0.1,\;0.2)$ ] crystals were grown by means of aqueous solution growth technique at 313 K. Structure analysis of them was carried out with space group $P6_{3}(#173)$ by X-ray diffraction. In these compounds, the Li and $SO_{4}^{2-}$ ions lying on the three-fold axes formed infinite three-dimensional network and K and Rb atoms located on the six-fold axes are coordinated by twelve and fifteen O atoms respectively. The most suitable stabilization was achieved when the occupancy factors of K and Rb atoms are (0.91 : 0.09), (0.77 : 0.23) 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.

• Korean Journal of Remote Sensing
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• v.36 no.2_1
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• pp.121-137
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• 2020

Data from the Ozone Monitoring Instrument (OMI) satellite and national emission inventories were used in this study to analyze air quality in East Asia and estimate the impact of domestic and foreign emissions on South Korea's air quality, based on which future emissions were predicted. The concentration trends of nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) in East Asia from 2005 to 2015 showed that both substances were highest in North East China (NEC), followed by South East China (SEC) and Seoul Metropolitan Area (SMA). The average SO₂ concentration was 1.63 times higher in NEC than in SMA. Analysis on the ratios of NO₂/SO₂ and NO_x/SO_x provides an indirect picture of the effect of transboundary air pollutants on atmospheric composition in Korea. The concentration ratio of NO₂/SO₂ in all study areas peaked in 2013 and SMA's emission ratio of NO_x/SO_x increased in 2015 by over 22% from 2013. Despite the reduction in domestic emissions, the concentration-to-emission ratios (NO₂/NO_x, SO₂/SO_x) rose gradually, which implies that other factors besides domestic emissions (e.g., foreign sources, lifetime, etc.) influence air quality in SMA. We estimated future emissions of NO_x and SO_x in SMA to be 296.2 and 39.0 ktons in 2025 and 284.4 and 33.8 ktons in 2035, respectively. Application of the inter-comparison techniques of this study to the data from the Geostationary Environment Monitoring Instrument (GEMS) is expected to provide concrete information which can be used to improve national emission inventories and figure out factors and sources that affect domestic air quality.

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.56-61
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• 2018

In Bunsen reaction section for the integrated operation of sulfur-iodine (SI) process, $I_2$ and $H_2O$ reactants are supplied as dissolved species in an $HI_x$ solution. Most of the $H_2SO_4$ product is found in the $HI_x$ phase when Bunsen reaction is performed using the $HI_x$ solution and $SO_2$ feed, so that the volume ratio of the $H_2SO_4$ phase to the $HI_x$ phase is very low. In this study, we investigated the effects of ultrasound irradiation on Bunsen reaction using the $HI_x$ solution to improve its phase separation performance. With ultrasound irradiation, the amount of $H_2SO_4$ moved to the $H_2SO_4$ phase from the $HI_x$ phase increased by up to 58.0 mol% and the volume of $H_2SO_4$ phase also increased by up to 13.1 vol%. In particular, the effect of ultrasound irradiation on the phase separation was improved with decreasing operating temperature, $I_2$ and $H_2O$ feed concentrations. The ultrasound irradiation induces the formation of additional $H_2O$ molecules by shifting microscopically the reaction equilibrium in the $HI_x$ phase. Afterward, the additionally generated $H_2O$ and isolated $H_2SO_4$ molecules form more $H_2SO_4{\cdot}xH_2O$ (x = 5-6) clusters that can be moved to the $H_2SO_4$ phase.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.153-159
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• 2004

This study was focused on evaluating physical properties and SO$_{x}$ removal capability of porous lime filters prepared by a foaming and a gelcasting method. Porosities of lime filters ranged from 55% to 85%, and their mean pore sizes were about 95 ${\mu}{\textrm}{m}$. It was observed that porous lime filters had the continuous pore structure that most pores were inter-connected by many windows. Before SO$_{x}$ removal reaction a surface of porous lime filters was made up of calcium oxide, but after reaction calcium sulfate became a main component. The SO$_{x}$ removal efficiency and the conversion ratio of calcium oxide to calcium sulfate increased according to reaction temperature and porosity. At 100$0^{\circ}C$, SO$_{x}$ removal efficiency of filters was always over 98% regardless of the porosity. In case of the filter with the porosity of 85%, the conversion ratios of calcium oxide increased according to the reaction temperature, and they were in the range 30% to 60%. to 60%.