• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.185-189
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• 2009

Absorption rate of carbon dioxide into aqueous ammonia absorbent(10 wt%) was measured in the temperature range from 293 K to 337 K using a stirred-cell reactor. The reaction rate constant was correlated with the Arrehnius equation and the activation energy was 50.42 kJ/mol. $CO_2$ absorption rate into modified ammonia absorbent was also investigated. For the modified ammonia absorbent, 1 wt% sterically hindered amines of 2-amino-2-methyl-1-propanol(AMP), 2-amino-2-methyl-1,3-propandiol(AMPD) and 2-amino-2-ethyl-1,3-propandiol(AEPD) were used as additives. The $CO_2$ absorption rate increased by adding 1 wt% of the amine additive, in the case of AMP additive, the absorption rate enhanced by about 53%.

• Journal of the Korean Chemical Society
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• v.43 no.1
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• pp.1-7
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• 1999

Metal colloidal particles have been prepared by a photo-chemical process in an aqueous solution containing semiconductor nanocrystallites. Metal colloidal particles produced in CdS and AgBr exhibit different absorption spectra. Au particles produced in solution with CdS show typical Au plasmon resonance absorption spectra. On the other hand Ag particles in solution with AgBr shows surface plasmon resonance absorption spectra which are red-shifted, as compared to that of a dispersion of homogeneous Ag colloidal particles in the same host. The extent of red-shift depends on the UV illumination time. This phenomenon is interpreted within the context of effective medium theory for small volume fractions. From the theory, a metal coated particle predicts Ag plasmon resonance, red shifted with respect to 400 nm that would be associated with a silver particle in solution. The absorption peak position is very sensitive to the coating thickness.

• Korea-Australia Rheology Journal
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• v.20 no.1
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• pp.1-6
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• 2008

Absorption rate of carbon dioxide was measured in the aqueous xanthan gum (XG) solution in the range of 0-0.15 wt% containing 2-amino-2-methyl-1-propanol (AMP) of $0-2\;kmol/m^3$ in a flat-stirred vessel with an impeller of 0.05m and agitation speed of 50rpm at $25^{\circ}C$ and 0.101 MPa. The volumetric liquid-side mass transfer coefficient ($k_La$) of $CO_2$, which was correlated with the viscosity and the elastic behavior of XG solution containing Deborah number as an empirical formula, was used to estimate the chemical absorption rate of $CO_2\;(R_A)$. $R_A$, which was estimated by mass transfer mechanism based on the film theory using the physicochemical properties and the kinetics of reaction between $CO_2$ and AMP, was compared with the measured rate. The aqueous XG solution with elastic property of non-Newtonian liquid made $R_A$ increased compared with Newtonian liquid based on the same viscosity of the solution.

• Journal of Energy Engineering
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• v.14 no.4 s.44
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• pp.219-225
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• 2005

for the removal of carbon dioxide in flue gas, which is the main cause of the global warming, chemical absorption methods were widely used for years. Alkanolamines such as MEA, AMP, MDEA are mainly used as an absorbent. In this study, cyclic amines - Piperazine, Piperidine and Cyclohelylamine are investigated to compare the chemical solubilities, absorption capacities and rate ot reaction. In conclusion, Piperazine is the most effective absorbent of $CO_2$ and ran be the excellent alternative to the former absorbents. Experiments were performed at 5, 10, 15 weight percent, 30, 40, $50^{\circ}C$, and the gas solubilities are determined by back-titration method, and using Gas Chromatography the absorption rate was compared.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3443-3447
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• 2011

The spectroscopic behavior of catechin (5,7,3',4'-tetrahydroxyflavan-3-ol), has been studied in the presence and the absence of air using UV-vis absorption spectrophotometry and fluorescence spectroscopy. The UV-vis absorption spectrum of catechin shows a very sharp and strong absorption maximum peak at 275 nm in deaerated water. New absorption maximum peaks appeared in aerated water, as well as in basic aqueous solution, caused by the oxidation of catechin. The absorbances in the UV-vis absorption spectrum of catechin decreased when the solution was left in the dark for a long time. The fluorescence emission spectrum of catechin after a long time period differs markedly from that in freshly prepared solution; the fluorescence maxia shifted as time passes after adding catechin to the solutions. When the deaerated basic catechin solutions were left in the dark for a long time, their fluorescence quantum yields were found to be nearly zero. This suggests that the oxidized catechin molecules were seen to have slowly undergone successive chemical reactions in basic buffer solution.

• Membrane Journal
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• v.28 no.2
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• pp.90-95
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• 2018

A process design was performed for a removal of acid gases using membrane-absorption hybrid system in LNG-FPSO. Commercial process simulator Promax version 4.0 was utilized for comparing acid gases removal capabilities of amine absorption process and hybrid process. Simulation results show hybrid process could be small amine solvent circulate rate, energy consumption, equipment sizing compared to typical amine absorption process. As a result, hybrid process which is small footprint and energy saving process may be a good solution for the pre-treatment of natural gas in LNG-FPSO.

• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.553-556
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• 1992

The ${CO}_2$ laser absorption measurement of ${CH}_3{CH}_2Br$ utilizing photoacoustic (PA) technique was performed using a cw and a pulsed ${CO}_2$ lasers. The absorption profile in the ${CO}_2$ laser wavelength region (9-10 ${\mu}$m) and the macroscopic small signal absorption cross section at 10P(20) (10.59 ${\mu}$m, 944 $cm^{-1}$) laser line were measured using a cw ${CO}_2$ laser. The laser fluence dependence on infrared multiphoton absorption (IRMPA) was also studied with a pulsed TEA ${CO}_2$ laser at 10P(20) laser line. In view of monotonic increase of PA signal with the rise of laser fluence, it was suggested that the anharmonicity in pumped vibration mode did not restrict ir multiphoton absorption in ${CH}_3{CH}_2Br$ system as found in large molecular system.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.335-339
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• 2014

The studies on the characteristics of composite of silica aerogel and pulps were carried out. The composite was manufactured by mixing the paste of silica aerogel and pulps and analyzed by SEM. Using the impedence tube, the sound absorption measurement was investigated. The maximum value of sound absorption coefficient of this composite was obtained in the range of 900 Hz. It was found that the composite of silica aerogel and pulps could be a new sound absorbent because of high absorption capacity and durability which was due to hydrophobic effect on the surface of the composite.

• Journal of Environmental Science International
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• v.14 no.10
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• pp.973-978
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• 2005

Biodegradable oil gelling agent was prepared, and their oil absorption capacities using light oil, lubricant oil and corn oil were investigated. The result showed that the oil absorption capacity was depended on the amount of surfactant and starch added, and was increased in the order of light oil, lubricant oil and corn oil. Also, the oil-absorption capacity was saturated within 30 min at $18^{\circ}C$. The biodegradability of the prepared biodegradable oil gelling agent was also studied by determination of reduced sugar produced after enzymatic hydrolysis. Their surface morphologies and thermal properties of the prepared biodegradable oil gelling agent were observed by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA), respectively.

• Journal of the Korean Chemical Society
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• v.10 no.3
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• pp.133-135
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• 1966

Rapid methods for determining chromium, nickel, and manganese in stainless steel by atomic absorption spectrophotometer are described. Use of suitable standards eliminates the need to separate each element prior to analysis. Comparison with the conventional wet chemical analysis shows that atomic absorption spectrophotometer is a reliable analytical tool in these applications.