• The Korean Journal of Food And Nutrition
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• v.28 no.5
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• pp.866-870
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• 2015

In this study, coffee waste was extracted with different solvents such as ethyl acetate, methylene chloride and methanol to investigate the total polyphenol contents, electron donating ability and the inhibitory effect on glutathione S-transferase. The total polyphenol contents were $3,060.61{\pm}357.12{\mu}g\;GAE/mL$ in ethyl acetate, $909.09{\pm}35.71{\mu}g\;GAE/mL$ in methylene chloride, and $1,602.27{\pm}30.36{\mu}g\;GAE/mL$ in methanol. The total polyphenol contents showed a significant difference (p<0.05) between the solvents. The electron donating ability was $80.20{\pm}1.45%$ for ethyl acetate, $81.94{\pm}0.45%$ for methylene chloride, and $85.14{\pm}1.53%$ for methanol. The electron donating abilities were significantly different (p<0.05) between the solvents. The inhibitory effect of the various extracts on glutathione S-transferase (% inhibition) was $92.12{\pm}0.56%$, $88.48{\pm}0245%$ with methylene chloride extract, and $90.85{\pm}0.14%$ with methanol extract. These too were significant different (p<0.05) between the solvents. The two portions of coffee waste extracts obtained from ethyl acetate and methanol showed meaningful results on the total polyphenol contents, and the inhibition effects on glutathione S-transferase. Therefore, they can be utilized to develop health care foods and can be applied as antioxidants for cosmeceuticals.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.220-224
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• 2017

In this study, we investigated a new recycling method of phenol resin, which is widely used to make electric insulation boards and adhesives, into carbon particles by using supercritical fluids. Because phenol resin is insoluble and infusible, most of the phenol resin wastes are buried in the ground or incinerated, which leads to environmental pollution. Therefore, development of a new method to recycle phenol resin waste is an urgent issue. In this study, phenol resin waste was treated with four sub/supercritical solvents: ethanol, acetone, water, and methanol. For all the sub/supercritical solvents, the phenol resin wastes were broken down into carbon nano particles at much lower temperatures than that required in the existing carbon particle manufacturing processes. We investigated the difference of morphologies and physical properties of recycled carbon particles according to the use of various solvents. As a result, carbon nano particles with the same amorphous structure were obtained from phenol resin waste with the usage of various sub/supercritical solvents at much lower temperature.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.255-265
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• 2018

The huge amount of solvents used in the semi-conductor and display industry typically result in waste of valuable solvents which often form complex azeotropic mixtures. This study explored a recovery process of a quaternary waste solvent, comprising methyl 2-hydroxybutyrate, propylene glycol monomethyl ether acetate, ethyl lactate, and ethyl-3-ethoxy propionate. In this study, a novel shortcut column method with a graphical approach was exploited for the distillation column design of complex quaternary azeotropic mixtures. As a result, the proposed shortcut method and design procedure solved the complex separation paths successfully with less computational efforts while achieving all requirements for component purity.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2019.05a
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• pp.287-288
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• 2019

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.410-411
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• 2018

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.549-562
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• 2020

Deionized water, methanol, and ethanol were investigated for their effectiveness at dissolving LiCl-KCl-UCl3 at 25, 35, and 50℃ using inductively coupled plasma mass spectrometry (ICP-MS) to study the concentration evolution of uranium and mass ratio evolutions of lithium and potassium in these solvents. A visualization experiment of the dissolution of the ternary salt in solvents was performed at 25℃ for 2 min to gain further understanding of the reactions. Aforementioned solvents were evaluated for their performance on removing the adhered ternary salt from uranium dendrites that were electrochemically separated in a molten LiCl-KCl-UCl3 electrolyte (500℃) using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). Findings indicate that deionized water is best suited for dissolving the ternary salt and removing adhered salt from electrodeposits. The maximum uranium concentrations detected in deionized water, methanol, and ethanol for the different temperature conditions were 8.33, 5.67, 2.79 μg·L-1 for 25℃, 10.62, 5.73, 2.50 μg·L-1 for 35℃, and 11.55, 6.75, and 4.73 μg·L-1 for 50℃. ICP-MS analysis indicates that ethanol did not take up any KCl during dissolutions investigated. SEM-EDS analysis of ethanol washed uranium dendrites confirmed that KCl was still adhered to the surface. Saturation criteria is also proposed and utilized to approximate the state of saturation of the solvents used in the dissolution trials.

• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.11-17
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• 1998

Chitin is known as biodegradable natural polymer. In spite of various application of chitin derivatives from waste marine sources, commercial use of chitin has been limited due to high resistance to chemicals and the absense of proper solvents. We chitin prepared through the decalcification, bleaching and deproteination from Protunus trituberculatus shells by change of Hackman's method. Also, Microcrystalline chitin made by hydrolysis that was reduce made of resistance solvents used by dilute hydrochloric acid, ultrasonic and hydrogen peroxide. Crosslinked chitin derivatives were preparaed from chitin with crosslink agents(epichlorohydrin, 1,3-dichloropropanol) follwed by crosslinkage at 6C position. The effects of these parameters on chitin dervatives were invastigated by IR, DSC, XRD, BET, PSA and SEM. SEM analysis showed that both chitin and crosslinked chitin had a particle shaped morphology.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3761-3767
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• 2009

This study was investigated to determine the combustion characteristics, decomposition efficiency, and the flue gas concentrations after combustion in the high temperature reactor($1,250{\sim}1,400^{\circ}C$, 1 atm) for the liquid wastes(waste oil and waste solvent) generated from the industrial complex. The concentration of nitrogen oxide(NOx) is decreased and the synthetic gas is increased when the mass ratio of $O_2$/waste is about 1.53 because the reaction condition was changed to reduction state. And BTEXs(benzene, toluene, ethylbenzene, xylene) are decomposed more than 99.99%. If the highly concentrated liquid waste (waste oil and waste solvent) is treated under the operating conditions suggested by this study, our treatment method for the liquid waste was found to be proper because of the contaminants emission concentration is very low. In addition, the synthetic gas after combustion can be used as an alternative fuel.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.606-614
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• 2017

Amount of food waste has been increased annually in Korea and re-use of food waste as a fertilizer or soil amendment in agricultural field has been studied. Therefore, main purpose of this research was to determine optimum condition of hydrolysis for food waste management. Three different solvents, HCl, $H_2SO_4$, and KOH, were used and varied concentration at the range of 10~30% and hydrolysis time at the range of 1~3 hours were evaluated. In general, reduction rate of food waste was increased when concentration of solvent and hydrolysis time was increased except when KOH was used. Among different solvents, concentration, and hydrolysis time, the highest reduction rate (97.79%) was observed when 30% of HCl was used with temperature of $140^{\circ}C$ at 2 hours of hydrolysis time. In addition, neutralization effect of alkalic materials, shell waste (SW) and egg shell (ES) was evaluated. Both SW and ES increased pH of finished acid hydrolysis solution up to 7.61 indicating that neutralization effect of SW and ES was sufficient for finished acid hydrolysis solution. Contents of organic matter was also at the range of 10.7~13.04% and 5.53~8.04% respectively when HCl and $H_2SO_4$ were used as solvent. Overall, hydrolysis technique can be used to manage food waste with selected optimum condition in this study and characteristics of finished hydrolysis solution after neutralization might be suitable for soil amendments.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.6
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• pp.665-674
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• 2000

A major source of the hazardous waste generated is from chemical industries producing plastics, herbicides, pesticides and chlorinated solvents. All of these processes produce a class if hazardous waste termed the chlorinated hydrocarbons(CHCs), either directly or from undesirable side reactions. In this study, we investigated the destruction characteristics of hazardous waste through incineration. A nonequilibrium combustion model was used to describe the effect of the chemical kinetics due to the flame inhibition characteristics of $CCl_4$ which was used as the surrogate of hazardous waste. A parametric screening studies was made in a dump incinerator proposed in this study. The dump incinerator showed high $CCl_4$ DRE(Destruction and Removal Efficiency) as 5 nines. $CCl_4$/CH$_4$ ratio appeared to be most important in the destruction of $CCl_4$ through incineration.