• Elastomers and Composites
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• 제51권1호
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• pp.49-55
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• 2016

Nanosized cobalt disulfide ($CoS_2$) particles were synthesized with 0.08 M cobalt chloride hexahydrate ($CoCl_2{\cdot}6H_2O$) and 0.2 M sodium thiosulfate pentahydrate ($Na_2S_2O_3{\cdot}5H_2O$) dissolved in distilled water under microwave irradiation. $[C_{60}]Fullerene-CoS_2$ nanocomposites were prepared with nanosized $CoS_2$ particles and [$C_{60}$]fullerene as heated by $700^{\circ}C$ for 2 h in an electric furnace. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) identified the heated $[C_{60}]fullerene-CoS_2$ nanocomposites. Heated $[C_{60}]fullerene-CoS_2$ nanocomposites were investigated the activity of photocatalytic degradation as a catalyst in various organic dyes like acid yellow 23, methylene blue, methyl orange, and rhodamine B with ultraviolet light at 254 nm by UV-vis spectrophotometer.

• Food Science and Biotechnology
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• 제18권3호
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• pp.717-723
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• 2009

Thermal degradation characteristics of sucrose was investigated. A 20% sucrose solution was heated to temperatures of $110-150^{\circ}C$ for 1-5 hr. Chromaticity, pH, organic acids, 5-hydroxymethylfurfural (HMF), free sugars, electron donating ability (EDA), and ascorbic acid equivalent antioxidant capacity (AEAC) of the heated sucrose solutions were evaluated. With increasing temperatures and times, the L-, a-, and b-values decreased; however, total color difference (${\Delta}E_{ab}$) increased. The pH and sucrose contents decreased, and fructose and glucose contents increased with increasing heating temperature and time. Organic acids, such as formic acid, lactic acid, and levulinic acid, and HMF contents increased with increasing heating temperatures and times. EDA (%) and the AEAC of the heated sucrose solutions increased with increasing heating temperature and time. The heated sucrose solution was more effective than unheated sucrose solution, having higher EDA (90 fold), and AEAC (13 fold).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.271.1-271.1
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• 2013

Titania is usually used in sun-screens, tooth paste, and other daily used objects as a pigment. However, scientists have focused on titania as photocatalyst due to its excellent activities. By fabricating vanadium doped TiO2 and CuOx co-catalyzed TiO2 nano-size filter, the degradation level of the volatile organic compound (VOC) concentration was tested using 365nm UV LED as light source in a closed chamber. Main purpose for this test is to evaluate the activities of various catalysts for degrading the VOCs which are detrimental to human body and toluene and p-xylene were chosen in the VOC removal test. Target gas materials were injected into the test chamber with dry air as carrier gas which was flowed into the gas washer bottle filled with liquid form of VOC substance. When the VOC gas flows into the chamber, it is circulated by 200 mm fan in order to contact with the set-up filter on the aluminum holder. Target gas concentration in the chamber was monitored using VOC detector (miniRae3000, Raesystems) which was also placed inside the chamber. With the measured concentration, the VOC degradation efficiency and the degradation rate were evaluated and used to compare the catalytic activities.

• Elastomers and Composites
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• 제57권4호
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• pp.181-187
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• 2022

CdSe-Mn nanocomposites were synthesized using a microwave method with sodium sulfite (Na₂SO₃), selenium (Se), cadmium sulfate octahydrate (3CdSO₄·8H₂O), ammonia solution (NH₃·H₂O), and manganese (II) sulfate monohydrate (MnSO₄·H₂O). We obtained CdSe-Mn-C₆₀ nanocomposites by calcining CdSe-Mn nanocomposites and fullerene (C₆₀) in an electric furnace at 700 ℃ for 2 h. X-ray diffraction, Raman spectroscopy, and scanning electron microscopy were used to characterize the crystal structures, lattice vibrations, and surface morphologies of the products, respectively. The photocatalytic activities of the CdSe-Mn-C₆₀ nanocomposites were investigated based on the photocatalytic degradations of organic dyes such as BG, MB, MO, and RhB under ultraviolet (UV) irradiation at 254 nm. UV-visible spectrophotometry was used to confirm the degradation process.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 춘계학술대회 및 임시총회
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• pp.43-43
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• 2014

White rot fungi have been useful source of enzymes for the degradation of environmental pollutants including polycyclic aromatic hydrocarbons (PAHs) and synthetic dyes. PAHs are widespread organic compounds present in fossil fuels and are routinely generated by incomplete fuel combustion. PAHs are some of the major toxic pollutants of water and soil environments. Synthetic dyes are major water-pollutants, which are toxic to organisms in water environments and interfere photosynthesis of water plants. Removal of PAHs and synthetic dyes has been of interests in the environmental science especially in the environmental microbiology. Mushrooms are fungal groups that function as primary degraders of wood polyphenolic lignin. The ligninolytic enzymes produced by mushroom, including manganese peroxidase, lignin peroxidase, and laccase, mediate the oxidative degradation of lignin. The catalytic power of these enzymes in the degradation of aromatic ring compounds has been sought for the degradation of various organic compounds. In this project, we have screened 60 wild mushroom strains for their degradation activity against two representative PAHs, naphthalene and anthracene, and five aromatic dyes, including alizarin red S, crystal violet, malachite green, methylene blue, rose bengal. The degradation of PAHs was measured by GC while the decolorization of dyes was measured by both UV spectrophotometer and HPLC. As results, 9 wild mushroom strains showed high activity in degradation of PAHs and textile dyes. We also describe the secretive enzyme activities, the transcription levels, and cloning of target genes. In conjunction with this, activities of degradative enzymes, including laccase, lignin peroxidase, and Mn peroxidase, were measured in the liquid medium in the presence of PAHs and dyes. Our results showed that the laccase activity was directed correlated with the degradation, indicating that the main enzyme acts on PAHs and dyes is the laccase. The laccase activity was further simulated by the addition of $Cu^{2+}$ ion. Detailed studies of the enzyme system should be sought for future applications.

• Korean Chemical Engineering Research
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• 제49권6호
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• pp.704-709
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• 2011

접촉글로우방전 전기분해(CGDE)에 의한 후코이단의 저분자화에 대해 연구하였다. CGDE 공정 후에 후코이단을 기능성 식품재료로 사용하기 위해 유기산을 전해질로 사용하였다. 실험결과 유기산을 이용한 전기분해에 의해 후코이단의 분자량을 효과적으로 감소시킴을 보였다. 전해질의 농도가 증가하면 글로우방전 시작 전압이 감소하고 글로우방전시작 전류는 증가하였다. 반응시간에 따른 후코이단의 분자량 변화로부터 저분자화반응은 1차 반응속도 식을 따름을 보였다. 유기산을 이용한 CGDE에 의해 후코이단의 분자량이 처음의 약 1/77로 감소하였으며, CGDE 저분자화 과정에서 유리된 황산기 함량이 작았다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.218-222
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• 2004

Batch slurry experiments were conducted to develop cement/slag/Fe(II) system that could treat hazardous liquid wastes containing halogenated organic solvents. Portland cement in combination with Fe(II) was reported to reductively dechlorinate chlorinated organics in a modified solidification/stabilization process. TCE (trichloroethylene) was used a model halogenated organic solvent. The objectives of this study were to assess the feasibility of using cement and steel converter slag amended with Fe(II) as a low cost abiotic reductive dechlorination and to investigate the kinetics of TCE dechlorination over a wide range of TCE concentration. From the result of screening experiments, cement/slag/Fe(II) system was identified as a potentially effective system to treat halogenated organic solvent. Kinetic studies were carried out to further investigate degradation reaction of TCE NAPL (Non Aqueous Phase Liquids) in cement/slag/Fe(II) systems by using batch slurry reactors. Degradation rate of TCE solution in this system can be explained by pseudo-first-order rate law because the prediction with the rate law is in good agreement with the observed data.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.943-946
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• 2001

In this study, We have investigated degradation effects of blue organic electroluminescence devices that was consisted of TPD(N,N'-dyphenyl-N-N\`-bis(3-methyphenyl) as hole transport layer and Butyl-PBD (2- (4-Biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole)-as emission layer and electron transport layer. We have studied characteristics of brightness and current density about blue OEL that was degradated layer. Two kinds of samples that were fabricated each continuous and non-continuous method was used.

• 산업기술연구
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• 제31권B호
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• pp.127-132
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• 2011

Humic substances is accounted for for the largest proportion in natural organic matter(NOM) and NOM is widely distributed in varying concentration in all aquatic and soil. They can affect water quality adversely in several ways by contributing undesirable color, complexing with metal and yielding metal concentrations exceeding normal solubility. Ozonation is one of the efficient treatments for degradation of humic substances which cause some problems in water treatment. Especially, the combination of ozone and granular activated carbon was applied to degradation humic acid in aquatic system. The aim of this work to test the available of acid-treated granular activated carbon as catalyst in the ozonation of humic acid.

• 한국해양공학회지
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• 제18권1호
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• pp.75-79
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• 2004

Organic coatings are widely used to control of the corrosion of a steel structure. The water in coatings may cause the coatings to swell, leading to the degradation of the coatings. In addition, water affects the permeation of oxygen and other corrosive agents, and consequently, the presence of such substances at coating-metal interface promotes corrosion of the metal substrate. In this study, the anticorrosive properties of 4 types of coating, such as epoxy-epoxy, epoxy-urethane, urethane-epoxy, urethane-urethane, were evaluated. The evaluation tests were conducted under cyclic water-absorption/desorption conditions, consisting of alternative exposure to diluted 0.001M-LiCl(a$H_2O$≒1) and concentrated 10M-LiCl(a$H_2O$≒0.15). The anticorrosive performance of coatings was found to decrease in the order of urethane-urethane > urethane-epoxy > epoxy-epoxy coating.