• Journal of the Korean Institute of Gas
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• v.21 no.4
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• pp.76-83
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• 2017

Biogas, combine with ever-increasing natural gas demand, has been on the center stage in South Korea for the early part of twenty first century in an effort to reduce the emission of global warming gases. With the passage of legal system of City Gas Business Law in 2014, the biogas has its place of production and distribution to consumers. However, it has a room for its technological improvements in terms of enrichment, by separating carbon dioxide and removing impurities efficiently. For these improvements, four different methane enrichment processes were tested in this study; membrane separation, water absorption, Chemical Absorption and Adsorption. A variety of operation scenarios were applied to the processes and the best practices were drawn out. The optimum process was selected based on case study results. Methane produced in this study showed 97% purity and 98% recovery rate, which meets the requirements of the City Gas quality standards.

• Korean Chemical Engineering Research
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• v.45 no.2
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• pp.197-202
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• 2007

This research was basically carried out to extend the application of $CO_2$ absorption processes for flue-gas system, which are mainly applied to a reforming process in petro-chemical industries. In general, MEA absorbent has some problems in flue-gas treatment, such as, degradation, regeneration energy and absorption capacities. As we known, sterical hindered amine, typically AMP (2-amino 2-methyl 1-propanol), have a good potential to improve these problems. In this paper, the characteristics of $CO_2$ absorption in aqueous AMP solution were measured and compared with that of MEA. It has been found that the $CO_2$ absorption capacity in AMP is double than that of MEA in the low $CO_2$ partial pressure system such as flue-gas. Also, the equilibriums of $CO_2$-AMP system were partially suggested, which are essentially needed to design the absorption process.

• Journal of Photoscience
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• v.11 no.3
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• pp.95-99
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• 2004

Optical absorption and emission studies have been carried out to understand the effect of deuterium on the solvent dependent photophysical properties of curcumin in deuterated solvents such as $CDCl_3,\;(CD_3)_2SO,\;(CD_3)_2CO,\;CD_3OD\;and\;CD_3CN$. Optical absorption spectral studies showed that there is no significant shift in absorption maxima compared to the non-deuterated solvent. The fluorescence maxima shows significant shift with polarity of solvent but not much affected by the deuteration. The fluorescence quantum yield of curcumin increased marginally in almost all the deuterated solvents, indicating reduction in the non-radiative pathways. The fluorescence decay was biexponential in all the solvents and the average fluorescence lifetime was not much affected with deuteration, but showed decrease with increasing solvent polarity. Based on these studies, it is concluded that intermolecular hydrogen transfer is only partially responsible for the excited state deactivation of curcumin.

• Clean Technology
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• v.15 no.4
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• pp.287-294
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• 2009

In order to separate the fuel-grade DME from the product of a direct DME synthesise reaction, containing 19~20% of DME, an absorption column and a purification column were employed. In the DME absorption column, the flow rate of the methanol required to recover more than 99% of DME at 50 bar was estimated by the correlation obtained from the lab-scale experiments. In the DME purification column, the maximum DME recovery of 98.2% could be obtained even from the side stream at the 3rd stage above the feed stage, since the feed stream originated from the product of the absorption column had already contained a large amount of DME (20~30 mol%) and only a small amount of light products such as $CO_2$ and $N_2$ (5~10 mol%).

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.783-787
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• 2013

The separation and capture process of carbon dioxide from power plants is garnering interest as a method to reduce greenhouse gas emissions. In this study, aqueous alkanolamine solutions were studied as absorbents for $CO_2$ capture. The solubility of $CO_2$ in aqueous alkanolamine solutions was investigated with a continuous stirred reactor at 313, 333 and 353 K. Also, the heat of absorption ($-{\Delta}H_{abs}$) between the absorbent and $CO_2$ molecules was measured with a differential reaction calorimeter (DRC) at 298 K. The solubility and heat of absorption were determined at slightly higher than atmospheric pressure. The enthalpies of $CO_2$ absorption in monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and 2-amino-2-methyl-1-propanol (AMP) were 88.91, 70.44, 44.72, and 63.95, respectively. This investigation showed that the heat of absorption is directly related to the quantity of heat for absorbent regeneration, and is dependent on amine type and $CO_2$ loading.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2732-2736
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• 2011

In pH 4.2 HAc-NaAc buffer solution, horseradish peroxidase (HRP) catalyzed $H_2O_2$ oxidation of nanosilver to form $Ag^+$. After centrifugation, $Ag^+$ in the supernatant can be measured by graphite furnace atomic absorption spectrophotometry (GFAAS) at the silver absorption wavelength of 328.1 nm. When HRP concentration increased, the $Ag^+$ concentration in the supernatant increased, and the absorption value enhanced. The HRP concentration in the range of 0.84-50 $ng{\cdot}mL^{-1}$ was linear to the enhanced absorption value (${\Delta}A$), with a regression equation of ${\Delta}A$=0.012C+0.11, correlation coefficient of 0.9988, and detection limit of 0.41 $ng{\cdot}mL^{-1}$ HRP. The proposed GFAAS method was used to detect HRP in waste water samples, with satisfactory results.

• Applied Chemistry for Engineering
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• v.1 no.1
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• pp.30-34
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• 1990

This paper summarizes fundamental research on a metal hydrides for the development of new energy. We made a study of the characteristics of the hydrogen absorption-desorption of $DiNi_5$ alloys. As a result, we found that the maximum amount of the hydrogen absorption of $DiNi_5$ alloys (the maximum in the absorption equilibrium pressure section) was H/M=1.04 at $30^{\circ}C$. The hysteresis was the smallest at $30^{\circ}C$. The capability of the hydrogen absorption-desorption was excellent. The number of cycles of the hydrogen absorption-desorption was about 9000 times at $30^{\circ}C$. We found also that the rate of the hydrogen desorption was the largest at $40^{\circ}C$.

• Journal of Environmental Science International
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• v.19 no.1
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• pp.97-103
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• 2010

The biodegradable oil absorption resin was prepared by the suspension polymerization of the modified starch and 2-ethylhexyl acrylate (2-EHA). The highest oil-absorption capacity of B-PEHA prepared showed at the condition of the modified starch content of 10 g and ethyleneglycol dimethacrylate (EGDMA) of 0.133 wt%. Its maximum oil absorption capacity per g of oil absorber was chloroform 30.88 g, toluene 19.75 g, xylene 18.78 g, tetrahydofuran (THF) 15.96 g, octane 11.43 g, hexane 9.5 g diesel oil 12.80 g, and kerosene 13.79 g, respectively. The biodegradation of poly-2-ethylhexylacrylate (B-PEHA) determined by enzymatic hydrolysis showed approximately 17~20%. The results showed that the preparation of the biodegradable oil absorption resin is available using the modified starch.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.392-396
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• 2014

New organic-inorganic composite of 2,4-dihydroxybenzophenone (BP-1) encapsulation into dodecylbenzenesulfonate (DBS) modified layered double hydroxide (LDH) was successfully prepared. The surface, structural, thermal and absorption properties of the BP-1/DBS-LDH nanohybrid was characterized by BET analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG) and diffuse reflectance UV-Vis absorbance spectra (DRUV-vis). The interlayer configuration of composite and the adsorption mechanism of BP-1 on MgAl-DBS-LDH were discussed. It was suspected that DBS anions located in the form of monolayer arrangement with a $75^{\circ}$ anti parallel angle between dodecylbenzenesulfonate chain axis. The diffuse reflectance UV-Vis absorbance results revealed that the UV absorbing wavelength of BP-1/DBS-LDH evidently extends to about 400 nm, which shows that the BP-1/DBS-LDH has the potential application as a UV absorber.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.597-600
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• 2012

Polyynes were formed by laser ablation of a graphite target in deionized water ($H_2O$ and $D_2O$) and various organic solvents such as acetonitrile, n-hexane, and c-hexane and were identified by analyzing ultraviolet (UV) absorption and Raman spectra. We assigned the major UV absorption peaks that coincided with the electronic transitions corresponding to linear polyyne chains. The UV absorption peak intensities of a polyyne solution decreased as the holding temperature of the solution increased. Also, the absorption spectra of polyynes obtained by laser ablation of a graphite target at different volume fractions of $H_2O$ and $D_2O$ were examined.