• Journal of Korean Society for Atmospheric Environment
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• v.23 no.5
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• pp.539-546
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• 2007

Increasing emission of $CO_2$ significantly effects the global warming. Chemical absorption is one of separation methods of $CO_2$ from the industrial flue gases. In this study, the $CO_2$ removal efficiency as well as the $CO_2$ absorption amount of aqueous AMP (2-amino-2-methyl-1-propanol) solutions were measured using the continuous absorption and regeneration apparatus. We investigated the effect of aqueous AMP+AEPD(2-amino-2-ethyl-1, 3-propanediol) and AMP+TIPA (triisopropanolamine) solutions to enhance absorption characteristics of AMP. As a result of this study, the absorption amount and $CO_2$ removal efficiency were increased with adding TIPA into 30 wt.% AMP. The absorption amount and $CO_2$ removal efficiency of aqueous 30 wt.% AMP+5 wt.% TIPA solution were $1.70\;kg-CO_2/kg-absorbent$ and 91.1%, while those of aqueous 30 wt.% AMP solution were $1.58\;kg-CO_2/kg-absorbent$ and 89.3%. In addition, aqueous 30 wt.% AMP+5 wt.% TIPA solution used in the study revealed the high stripping efficiency, which was almost 98%, at the temperature of $110^{\circ}C$. Thus, the temperature of regenerator should be operated at $110^{\circ}C$.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.E2
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• pp.97-106
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• 2002

The purpose of this study was to quantitatively estimate the washout removal efficiencies of criteria air pollutants such as SO$_2$, TSP, PM10, CO, NO$_2$, and O$_3$corresponding to the amounts and durations of precipitation. The removal patters by washout were studied with air pollutants data and the corresponding precipitation data in Seoul, Korea during the periods of 1990 to 1999. In addition, washout patterns were classified into four seasons and four time Bones, i.e., night, morning, afternoon, and evening. In this study, natures of air pollutants by sequential precipitation were also intensively studied by examining the linear relationships between removal efficiencies and the amounts and durations of precipitation for each pollutant. The results of this study showed that SO$_2$, TSP, and O$_3$were rapidly removed by initial precipitation; however, NO$_2$was slowly removed 2-hour after precipitation. Both CO and PM10 were weakly removed by washout and their removal patters showed to be irregular.

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.112-118
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• 1996

When fossil fuels are burned they produce CO gas because of incomplete combustion. If the CO gas reacts with the hemoglobin in the red blood cells, it may result in death or sequelae. Generally, the CO gas is eliminated in the form of the $$$CO_2$ gas by the oxidation reaction over the platinum catalyst. In this study, the electrochemical CO removal was investgated by using the solid electrolyte cell reactor, the type of which was represented as reactants$/Pt/Y_2O_3-ZrO_2/Pt/Air$. If the overpotential was applied to the platinum working electrode, the conversion could be changed with the overpotential applied. It was found that the oxidation rate could be increased 2.8 times higher than that of the normal condition, i. e. under open circuit conditions when $P_{co}/P_{O_2}$ was 0.5 and overpotential was 0.9V. From these results, it is concluded that the reactor used in this study is more efficient than conventional catalytic reactors.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.101-107
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• 2016

This paper investigates the feasibility of applying the jet loop reactor for the neutralization of alkaline wastewater using carbon dioxide ($CO_2$). In this study, pH changes and $CO_2$ removal characteristics were examined by changing influent flow rate of alkaline wastewater (initial pH=10.1) and influent $CO_2$ flow rates. Influent flow rates of alkaline wastewater ($Q_{L,in}$) ranged between 0.9 and 6.6 L/min, and inlet gas flow rate ($Q_{G,in}$) of 1 and 6 L/min in a lab-scale continuous flow jet loop reactor. The outlet pH of wastewater was maintained at 7.2 when the ratio ($Q_{L,in}/Q_{G,in}$) of $Q_{L,in}$ and $Q_{G,in}$ was 1.1. However, the $CO_2$ removal efficiency and the outlet pH of wastewater were increased when $Q_{L,in}/Q_{G,in}$ ratio was higher than 1.1. Throughout the experiments, the maximum $CO_2$ removal efficiency and the outlet pH of wastewater were 98.06% and 8.43 at the condition when $Q_{G,in}$ and $Q_{L,in}$ were 2 L/min and 4 L/min, respectively.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.206-211
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• 2005

Mediated electrochemical oxidation (MEO) of polyethylene glycols (PEGs) of molecular weight of 1000, 4000 and 20000, was carried out on both platinum (Pt) and titanium-iridium electrodes in 8.0 M nitric acid solution containing 0.5 M Fe(II) and Co(II) ion. The electrochemical parameters such as current densities, kinds of electrode, electrolyte concentration and removal efficiency were investigated in both Fe(III)/Fe(II) and Co(III)/Co(II) redox systems. The PEGs was decomposed into carbon dioxide by MEO in Fe(III)/Fe(II) and Co(III)/Co(II) redox system during 180 min and 210 min at the current density of $0.67A/cm^2$ on the Pt electrode. Removal efficiency of PEGs by MEO was better in Co(III)/Co(II) redox system than Fe(III)/Fe(II) redox system, indicating mediated electrochemical removal efficiency was 100%.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.986-994
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• 2017

In this paper, $CO_2$ absorption of scrubber was tested for removal of high concentration $CO_2$. Liquid to gas ratio($18L/m^3$) and Superficial velocity(0.14 m/s) was determined through Lab-scale test. As flow rates increase 1, 2, 3, 4 and $5m^3/min$, $CO_2$ removal efficiency decrease 98.47%, 96.46%, 92.95%, 89.71% and 85.49%. Also, the scrubber operation made energy improvement(5.4%), energy saving(11.5 TOE/year) and greenhouse gases reduction(6.5 TC/year).

• Journal of Environmental Health Sciences
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• v.28 no.1
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• pp.51-65
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• 2002

This study was carried out to apply some basic physical and chemical treatment options including Fenton's oxidation, and to evaluate the performances and the characteristics of organic and nitrogen removal using lab-scale biological treatment system such as complete-mixing activated sludge and sequencing batch reactor(SBR) processes for the treatment of leachate from a municipal waste landfill in Gyeongnam province. The results were as follows: Chemical coagulation experiments using aluminium sulfate, ferrous sulfate and ferric chloride resulted in leachate CO $D_{Cr}$ removal of 32%, 23% and 21 % with optimum reaction dose ranges of 10,000～15,000 mg/$\ell$, 1,000 mg/$\ell$ and 500～2,000 mg/$\ell$, respectively. Fenton's oxidation required the optimum conditions including pH 3.5, 6 hours of reaction time, and hydrogen peroxide and ferrous sulfate concentrations of 2,000 ～ 3,000 mg/$\ell$ each with 1:1 weight ratio to remove more than 50% of COD in the leachate containing CO $D_{Cr}$ between 2,000 ～ 3,000 mg/$\ell$. Air-stripping achieved to remove more than 97% of N $H_3$-N in the leachate in spite of requiring high cost of chemicals and extensive stripping time, and, however, zeolite treatment removing 94% of N $H_3$-N showed high selectivity to N $H^{+}$ ion and much faster removal rate than air-stripping. The result from lab-scale experiment using a complete-mixing activated sludge process showed that biological treatability tended to increase more or less as HRT increased or F/M ratio decreased, and, however, COD removal efficiency was very poor by showing only 36% at HRT of 29 days. While COD removal was achieved more during Fenton's oxidation as compared to alum treatment for the landfill leachate, the ratio of BOD/COD after Fenton's oxidation considerably increased, and the consecutive activated sludge process significantly reduced organic strength to remove 50% of CO $D_{Cr}$ and 95% of BO $D_{5}$ . The SBR process was generally more capable of removing organics and nitrogen in the leachate than complete-mixing activated sludge process to achieve 74% removal of influent CO $D_{Cr}$ , 98% of BO $D_{5}$ and especially 99% of N $H_3$-N. However, organic removal rates of the SBR processes pre-treated with air-stripping and with zeolite were not much different with those without pre-treatment, and the SBR process treated with powdered activated carbon showed a little higher rate of CO $D_{Cr}$ removal than the process without any treatment. In conclusion, the biological treatment process using SBR proved to be the most applicable for the treatment of organic contents and nitrogen simultaneously and effectively in the landfill leachate.e.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.578-582
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• 2015

In this study, We evaluated the efficiency of the smart ventilation system being developed at the test-bed(KCL). Smart ventilation system improve the indoor air quality by absorbing carbon dioxide. It is reducing the infusion of outside air can be reduced to minimum energy consumption. To evaluate the energy savings and carbon dioxide removal efficiency. It was more effective when working with air conditioning and ventilation system at the same time.

• Clean Technology
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• v.24 no.3
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• pp.157-165
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• 2018

In this study, the removal of $Si_3N_4$ particles from the surface of a silicon wafer was investigated by using supercritical carbon dioxide, the IPA co-solvent and cleaning additive chemicals. First, the solubility of several surfactants and binders in supercritical carbon dioxide solubility and particle dispersibility in the binders were evaluated in order to confirm their suitability for the supercritical cleaning process. Particle removal experiments were carried out with adjusting various process parameters and reaction conditions. The surfactants used in the experiment showed little particle removal effect, producing secondary contamination on the surface of wafers. On the other hand, 5 wt% (with respect to $scCO_2$) of the cleaning additive mixture of trimethyl phosphate, IPA, and trace HF resulted in 85% of particle removal efficiency after $scCO_2$ flowing for 4 minutes at $50^{\circ}C$, 2000 psi, and the flow rate of $15mL\;min^{-1}$.

• Journal of Environmental Science International
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• v.17 no.3
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• pp.335-342
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• 2008

This study based on electro-coagulation & oxidation reaction is applied to wastewater treatment. Electro-oxidation reaction is used to remove cyanide(CN) which is contained in plating wastewater. Cyanide is transferred by gases such as $NH_3,\;NO_x,\;CO_2$. Analysis result and removal efficiency of Cyanide which is contained in heavy metal wastewater of plating plant, are shown as following paragraph. In electrode arrangement experiment, removal efficiency of carbon electrode(-)/STS316L electrode(+) arrangement method is superior to carbon electrode(-)/carbon electrode(+) arrangement method. Removal efficiencies of cyanide in different HRT such as 30 min, 45 min, 60 min, 75 min and 90 min are 85.5%, 93.1%, 98.0%, 98.7% and 99.4% respectively in carbon electrode(-)/STS316L electrode(+) arrangement method. Finally we can estimate the critical point at HRT of 60 min which the variation of removal efficiency is decreased and HRT to obtain removal efficiency of less than 1 mg/LCN is minimum 90 min.