• Journal of Powder Materials
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• v.28 no.2
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• pp.150-163
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• 2021

Interest in eco-friendly materials with high efficiencies is increasing significantly as science and technology undergo a paradigm shift toward environment-friendly and sustainable development. MXenes, a class of two-dimensional inorganic compounds, are generally defined as transition metal carbides or nitrides composed of few-atoms-thick layers with functional groups. Recently MXenes, because of their desirable electrical, thermal, and mechanical properties that emerge from conductive layered structures with tunable surface terminations, have garnered significant attention as promising candidates for energy storage applications (e.g., supercapacitors and electrode materials for Li-ion batteries), water purification, and gas sensors. In this review, we introduce MXenes and describe their properties and research trends by classifying them into two main categories: transition metal carbides and nitrides, including Ti-based MXenes, Mo-based MXenes, and Nb-based MXenes.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.1-7
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• 2017

This study was conducted to investigate changes in ginsenoside by continuously treating fine bubble, which are mainly used for environmental purification, in 2-year-old ginseng. The ginsenoside content and composition of ginseng leaves and roots were analyzed for 4 months (120 days) after application of Fine bubble. As a result of treatment with common water in leaves, only Re of protopanaxatriol was significantly higher and As a result of treatment with fine buble, it was confirmed that protopanaxadiol Rb1, RC, Rb2 and Rd components were also increased. Especially, the increase of Re and Rb1 resulted in an increase of total ginsenoside. The ratio of PD / PT to ginseng was 0.811 in finebubble treated leaves and 1.28 in root. The fine bubble treatment induced the synthesis of ginsenoside from the roots and resulted in a PD / PT ratio of close to 1. Therefore, this study suggests a method of cultivating high quality ginseng using fine bubble water and suggests possibility of using it as a functional food material which can be used with leaves as well as roots.

• Journal of the Mineralogical Society of Korea
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• v.16 no.4
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• pp.283-293
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• 2003

Domestic water treatment plants operate the rapid and slow filtering system using the filtering sands. Most of them are composed of beach sands, which have less sorption capacity of heavy metals as well as organic contaminants. Therefore, the development of fortified functional filtering materials with high removal capacity of organic and inorganic contaminants is needed to prevent the unexpected load of contaminated source water. This study aims to test the hydrochemical change and the removing capacity of heavy metals such as Cd, Cu, and Pb on the Jumunjin sand, feldspathic sand(weathering product of Jecheon granite), feldspathic mixing sand I(feldspathic sand mixed with 10 wt% zeolite), and feldspathic mixing sand II (feldspathic sand mixed with 20 wt% zeolite). Feldspathic mixing sand I and II showed the eruption of higher amounts of cations and anions compared with the Jumunjin sand and feldspathic sand. They also showed higher eruption of Si, Ca, $SO_4$ ions than that of Al, $NO_3$, Fe, K, Mg, and P. Feldspathic mixing sand II caused higher eruption of some cations of Na, Ca, Al than feldspathic mixing sud I, which is the result controlled by the dissolution of zeolite. Jumunjin sand and feldspathic sand showed very weak sorption of Cd, Cu and Pb. In contrast to this, feldspathic mixing sand I and II showed the high sorption and removal capacity of the increasing order of Cd, Cu and Pb. Feldspathic mixing sand II including 20% zeolite showed a fortified removal capacity of some heavy metals. Therefore, feldspathic mixing sand mixed with some contents of zeolite could be used as the fortified filtering materials for the water filtering and purification in the domestic water treatment plants.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.342-349
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• 2010

Lactic acid is widely used in the food, chemical and pharmaceutical industries, and there is an increasing demand for lactic acid as the raw material of poly lactic acid(PLA), which is a biodegradable polymer. Lactic acid production has been changing over from production by synthesis to production by fermentation, since the fermentation process is more nature friendly and economic. However, the fermentation method generates excess water and impurities with high boilers. The presence of high boilers and non volatility of lactic acid makes the separation of lactic acid very difficult job. Also, the purification-separation process requires the many investment costs and energy costs. Reactive distillation concept was also introduced for the process, giving higher selectivity and yield compared to the convention method. We introduce a new highly integrated process, reactive diving wall column, to reduce the capital and energy cost for producing a pure lactic acid. The reactive dividing wall column combines reactive distillation and dividing wall column. We compared capital and energy consumption required for the purification of lactic acid the between the proposed design structures. And we examined the effect of major process variables on the process performance and determined optimal process.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.162-170
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• 1996

Light cycle Oil(LCO) contains 2,6-dimethylnaphthalene (2,6-DMNA) which is used as the basic material for high performance engineering plastics and liquid crystal polymer. This study was experimentally investigated to concentrate a mixture of dimethylnaphthalene(DMNA) isomers in the LCO by extraction-distillation combination as a pretreatment for separation and purification of 2,6-DMNA in the LCO. Furthermore, concentration of a mixture of DMNA isomers in the LCO compared between distillation and extraction-distillation combination. The recovery of aromatics in the LCO was performed by batch cocurrent multistage extraction with dimethylsulfoxide and water mixture as solvent. The concentration of naphthalene group(carbon number 10-12) in the extracted mixture is higher than that in the LCO. The yield for naphthalene group increased with decreasing carbon number. The yield for a mixture of DMNA isomers obtained in 5 equilibrium extration runs was about 65%. the separation of individual components with extractedmixture was tested by batch distillation. Futhermore, for recovery of a mixture of DMNA isomers of high concentration, distillate containing DMNA was distilled. As a result, a mixture of DMNA isomers with high concentration such as 60wt% was recovered. The extraction-distillation combination was more effective than the distillation to concentration a mixture of DMNA isomer in the LCO.

• Membrane Journal
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• v.33 no.4
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• pp.181-190
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• 2023

Wastewater purification is one of the most important techniques for controlling environmental pollution and fulfilling the demand for freshwater supply. Various technologies, such as different types of distillations and reverse osmosis processes, need higher energy input. Capacitive deionization (CDI) is an alternative method in which power consumption is deficient and works on the supercapacitor principle. Research is going on to improve the electrode materials to improve the efficiency of the process. A reverse electrodialysis (RED) is the most commonly used desalination technology and osmotic power generator. Among many studies conducted to enhance the efficiency of RED, MXene, as an ion exchange membrane (IEM) and 2D nanofluidic channels in IEM, is rising as a promising way to improve the physical and electrochemical properties of RED. It is used alone and other polymeric materials are mixed with MXene to enhance the performance of the membrane further. The maximum desalination performances of MXene with preconditioning, Ti₃C₂T_x, Nafion, and hetero-structures were respectively measured, proving the potential of MXene for a promising material in the desalination industry. In terms of osmotic power generating via RED, adopting MXene as asymmetric nanofluidic ion channels in IEM significantly improved the maximum osmotic output power density, most of them surpassing the commercialization benchmark, 5 Wm^-2. By connecting the number of unit cells, the output voltage reaches the point where it can directly power the electronic devices without any intermediate aid. The studies around MXene have significantly increased in recent years, yet there is more to be revealed about the application of MXene in the membrane and osmotic power-generating industry. This review discusses the electrodialysis process based on MXene composite membrane.

• Journal of Life Science
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• v.13 no.5
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• pp.668-674
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• 2003

This study was carried out to investigate the ACE inhibitory materials of Raja kenojei. Raja kenojei was sperated to fillet and viscera, and these were extracted with hot water. Antihypertensive activity was examined by mesearing angiotensin converting enzyme ACE inhibitory activity. ACE inhibitory activity of viscera at the concentration of 2% for Day 0 showed the highest value by 71.0%. But ACE inhibitory activity of fillet at 2% showed by 29%, which was lower antihypertensive activity than viscera. The protein content of viscerial hot water extracts in proximate composition showed the highest. And also, there was a large amount of aromatic and branched aliphatic amino acids in viscera than those in fillet. For the purification of antihypertensive material in visceral hot water extracts, it was separated and collected by Sephadex G-25 gel chromatography. The fraction (B) of 111 to 160 showed the highest ACE inhibitory activity by 65.1% at the concentration of 0.05%. But the other fractions (A and C) showed lower activity than B. These results demonstrate that crude hot water extracts of viscera from Raj kenojei may be useful as functional food ingredient with antihypertensive property.

• Food Science of Animal Resources
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• v.37 no.5
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• pp.743-751
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• 2017

During slaughtering, animal blood is typically discarded, resulting in water pollution. However, this discarded blood has valuable components, such as immunoglobulin (Ig). Although several studies have been conducted to develop methods for effective recycling of slaughterhouse blood, they have not been commercially utilized in Korea. Here, we extracted an Ig-rich fraction from porcine blood that was then subjected to various in vitro tests, including pathogen growth inhibition, antigenic cross-reactivity, and anti-toxin activity. The porcine immunoglobulin concentrate (PIC) was effectively purified by eliminating other components, such as albumin, and consisted of approximately $63.2{\pm}2.9%$ IgG and $7.2{\pm}0.4%$ IgM on a protein basis. The results showed that it significantly suppressed the growth of pathogenic bacteria, and bound to all tested pathogens, including both gram-positive and gram-negative species, although the degree of activity differed according to strain. The PIC bound to two types of lipopolysaccharide (LPS) obtained from Escherichia coli O111:B4 and Salmonella enterica serotype typhimurium in a concentration-dependent manner. In addition, the PIC restored the proliferation activity of the lymphoblast K-562 cells when co-incubated with pathogenic LPS. These results confirm that the PIC prepared in this study is a potentially valuable functional food material or diet supplement as an alternative to antibiotics that can protect animals from pathogenic bacteria.

• Applied Biological Chemistry
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• v.15 no.1
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• pp.27-33
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• 1972

The alkaline protease was isolated from the culture material of monascus sp. on wheat bran culture. The crude purification of this enzyme was extracted with distilled water and precipitated with ammonium sulfate of 0.5 saturation. And, the activity of this enzyme was determind very strongly by folin's colorimetric method. The optimal pH of this enzyme was ranging from pH 10 to 13 and the optimal temperature was $50^{\circ}C$. The pH stability was ranging from pH 5 to 12 and the enzyme activity was not inactivated by heat treatment in lower temperature than $40^{\circ}C$. The enzyme was protected from heat denature by the treatment of $Pb^#$, $Ba^#$, $Co^#$, $Zn^#$, and $Cu^#$, but was inactivated with $Hg^#$, $Fe^#$ strongly. Moreover, one of these metal ions, the cupper ion, has a strong protective activity on enzyme heat denature. And, it was not effected by treatment of EDTA.

• Carbon letters
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• v.26
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• pp.31-42
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• 2018

Adsorption is one of the best methods for wastewater purification. The fact that water quality is continuously decreasing requires the development of novel, effective and cost available adsorbents. Herein, a simple procedure for the preparation of a magnetic adsorbent from agricultural waste biomass and ferrofluid has been introduced. Specifically, ferrofluid mixed with wheat straw was directly pyrolyzed either by microwave irradiation (900 W, 30 min) or by conventional heating ($550^{\circ}C$, 90 min). Magnetic biochars were characterized by X-ray powder diffraction, $M{\ddot{o}}ssbauer$ spectroscopy, textural analysis and tested as adsorbents of As(V) oxyanion and cationic methylene blue, respectively. Results showed that microwave pyrolysis produced char with high adsorption capacity of As(V) ($Q_m=25.6mg\;g^{-1}$ at pH 4), whereas conventional pyrolysis was not so effective. In comparison to conventional pyrolysis, one-step microwave pyrolysis produced a material with expressive microporosity, having a nine times higher value of specific surface area as well as total pore volume. We assumed that sorption properties are also caused by several iron-bearing composites identified by $M{\ddot{o}}ssbauer$ spectroscopy ([super] paramagnetic $Fe_2O_3$, ${\alpha}-Fe$, non-stoichiometric $Fe_3C$, ${\gamma}-Fe_2O_3$, ${\gamma}-Fe$) transformed from nano-maghemite presented in the ferrofluid. Methylene blue was also more easily removed by magnetic biochar prepared by microwaves ($Q_m=144.9mg\;g^{-1}$ at pH 10.9) compared to using conventional techniques.