• Korean Chemical Engineering Research
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• 제48권3호
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• pp.300-303
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• 2010

세계 각국은 폐기물의 발생 및 처리 문제를 극복하기 위해 많은 노력을 기울이고 있다. 특히, 매년 발생량이 증가하고 있는 폐산은 처리보다는 재활용에 대한 관심이 크게 증가하고 있는 상황이지만, 국내외적으로 재활용 생성물의 품질규정이 불명확하고 관리체계 또한 미비한 실정이다. 따라서 폐산 생성물의 효율적 관리방안을 마련하기 위해 본 연구에서는 국내의 폐산 발생 및 재활용 관련 현황을 조사하였으며, 이를 통해 현재 국내에서 재활용되고 있는 폐산의 주요 생성물을 조사하였다. 그 결과 염화철, 황산철, 청화제1동, 산화동, 치환동이 주요 재활용 생성물인 것으로 나타났다. 장차 이들 생성물에 대한 체계적인 관리체제를 구축함으로서 폐산 자원화를 제고할 뿐 아니라 환경오염 방지와 같은 긍정적인 결과를 기대할 수 있을 것이다.

• 한국재료학회지
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• 제21권1호
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• pp.21-27
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• 2011

A nano-porous structure of tin oxide was prepared using an anodic oxidation process and the sample's electrochemical properties were evaluated for application as an anode in a rechargeable lithium battery. Microscopic images of the as-anodized sample indicated that it has a nano-porous structure with an average pore size of several tens of nanometers and a pore wall size of about 10 nanometers; the structural/compositional analyses proved that it is amorphous stannous oxide (SnO). The powder form of the as-anodized specimen was satisfactorily lithiated and delithiated as the anode in a lithium battery. Furthermore, it showed high initial reversible capacity and superior rate performance when compared to previous fabrication attempts. Its excellent electrode performance is probably due to the effective alleviation of strain arising from a cycling-induced large volume change and the short diffusion length of lithium through the nano-structured sample. To further enhance the rate performance, the attempt was made to create porous tin oxide film on copper substrate by anodizing the electrodeposited tin. Nevertheless, the full anodization of tin film on a copper substrate led to the mechanical disintegration of the anodic tin oxide, due most likely to the vigorous gas evolution and the surface oxidation of copper substrate. The adhesion of anodic tin oxide to the substrate, together with the initial reversibility and cycling stability, needs to be further improved for its application to high-power electrode materials in lithium batteries.

• Korean Chemical Engineering Research
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• 제44권2호
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• pp.193-199
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• 2006

${\gamma}-Al_2O_3$에 담지한 Cu-Mn 산화물 촉매에서 톨루엔 완전산화 반응을 $160{\sim}280^{\circ}C$의 온도 범위에서 고정층 반응기로 조사하였다. BET, SEM, TPR, TPO, XPS 및 XRD를 이용하여 촉매 특성분석을 하였다. 톨루엔의 완전산화 반응은 $280^{\circ}C$ 이하에서 이루어졌으며, 적절한 Cu-Mn 담지량은 15.0 wt％Cu-10.0 wt％Mn인 것으로 나타났다. TPR/TPO 및 XPS 분석 결과, 15 Cu-10 Mn 촉매의 산화환원 봉우리가 낮은 온도로 이동하였으며 결합에너지가 높은 값으로 이동하였다. XRD 결과, 고분산된 Mn 산화물과 CuO 보다 $Cu_{1.5}Mn_{1.5}O_4$의 촉매활성 인자로서의 역할이 더욱 우수한 것으로 추측되며, 촉매의 활성은 촉매의 산화환원 능력과 촉매의 높은 산화 상태에 기인하는 것으로 사료된다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.54-61
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• 2000

A method and results of classification of 4 types metallic wear debris were presented by using their color features. The color image of wear debris was used (or the initial data, and the color properties of the debris were specified by HSI color model. Particle was characterized by a set of statistical features derived from the distribution of HSI color model components. The initial feature set was optimized by a principal component analysis, and multidimensional scaling procedure was used for the definition of classification plane. It was found that five features, which include mean values of H and S, median S, skewness of distribution of S and I, allow to distinguish copper based alloys, red and dark iron oxides and steel particles. In this work, a method of probabilistic decision-making of class label assignment was proposed, which was based on the analysis of debris-coordinates distribution in the classification plane. The obtained results demonstrated a good availability for the automated wear particle analysis.

• KSTLE International Journal
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• 제1권1호
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• pp.34-42
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• 2000

A method and results of classification of four different metallic wear debris were presented by using their color features. The color image of wear debris was used far the initial data, and the color properties of the debris were specified by HSI color model. Particles were characterized by a set of statistical features derived from the distribution of HSI color model components. The initial feature set was optimized by a principal component analysis, and multidimensional scaling procedure was used fer the definition of a classification plane. It was found that five features, which include mean values of H and S, median S, skewness of distribution of S and I, allow to distinguish copper based alloys, red and dark iron oxides and steel particles. In this work, a method of probabilistic decision-making of class label assignment was proposed, which was based on the analysis of debris-coordinates distribution in the classification plane. The obtained results demonstrated a good availability for the automated wear particle analysis.

• 한국조명전기설비학회지:조명전기설비
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• 제11권1호
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• pp.99-105
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• 1997

본 논문에서는 주상변압기 절연유의 가속열화반응을 수행하였다. 유중가스를 air bubbling 법으로 추출하여 가스크로마토크라프로 성분을 분석하였으며 가스농도는 각 가스의 추출율을 감안하여 보정하였다. 절연재료의 열화는 열분해반응과산화반응에의하여 진행되었으며 두 종류의 반응은 모두 0차반응의 특성을 보였고 탄화수소류, CO+{{{{ { CO}_{2 } }}}} 및 수소가스의 생성속도식을 얻었다. 유중가스 분석과 UV-Visible 분광광도법에 의하여 변압기내의 철심과 동코일이 열화과정에서 촉매역활을 함을 확인하였다.

• 한국조명전기설비학회지:조명전기설비
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• 제11권1호
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• pp.24-33
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• 1997

본 논문에서는 주상변압기 절연유의 가속열화반응을 수행하였다. 유중가스를 air bubbling법으로 추출하여 가스크로마토그라프로 성분을 분석하였으며 가스농도는 각 가스의 추출율을 감안하여 보정하였다. 절연재료의 열화는 열분해반응과 산화반응에 의하여 진행되었으며 두종류의 반응은 모두 0차반응의 특성을 보였고 탄화수소류, $CO+CO_2$ 및 수소가스의 생성속도식을 얻었다. 유중가스 분석과 UV-Visible 분광광도법에 의하여 변압기내의 철심과 동코일이 열화과정에서 촉매역활을 함에 확인하였다.

• 한국환경농학회지
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• 제19권5호
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• pp.401-418
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• 2000

1. Production of the artificial zeolite from coal ash Coal fly ash is mainly composed of several oxides including $SiO_2$ and $Al_2O_3$ derived from inorganic compounds remained after burning. As minor components, $Fe_2O_3$ and oxides of Mg, Ca, P, Ti (trace) are also contained in the ash. These components are presented as glass form resulting from fusion in the process of the combustion of coal. In other word, coal ash may refer to a kind of aluminosilicate glass that is known to easily change to zeolite-like materials by hydrothermal reaction. Lots of hot seawater is disposing near thermal power plants after cooling turbine generator periodically. Using seawater in the hydrothermal reaction caused to produce low price artificial zeolite by reduction of sodium hydroxide consumption, heating energy and water cost. As coal ash were reacted hydrothermally, peaks of quartz and mullite in the ash were weakened and disappeared, and new Na-Pl peaks were appeared strengthily. Si-O-Si bonding of the bituminous coal ash was changed to Si-O-Al (and $Fe^{3+}$) bonding by the reaction. Therefore the produced Na-Pl type zeolite had high CEC of 276.7 $cmol^+{\cdot}kg^{-1}$ and well developed molecular sieve structure with low concentration of heavy metals. 2. Utilization of the artificial zeolite in agro-environment The artificial zeolite(1g) could remove 123.5 mg of zinc, 164.7 mg copper, 184.4 mg cadmium and 350.6 mg lead in the synthetic wastewater. The removability is higher 2.8 times in zinc, 3.3 times in copper, 4.7 times in cadmium and 4.8 times in lead than natural zeolite and charcoal powder. When the heavy metals were treated at the ratio of 150 $kg{\cdot}ha^{-1}$ to the rice plant, various growth inhibition were observed; brownish discoloration and death of leaf sheath, growth inhibition in culm length, number of panicles and grains, grain ripening and rice yield. But these growth inhibition was greatly alleviated by the application of artificial zeolite, therefore, rice yield increased $1.1{\sim}3.2$ times according to the metal kind. In addition, the concentration of heavy metals in the brown rice also lowered by $27{\sim}75%$. Artificial Granular Zeolites (AGZ) was developed for the purification of wastewater. Canon exchange capacity was 126.8 $cmol^+{\cdot}kg^{-1}$. AGZ had Na-Pl peaks mainly with some minor $C_3S$ peaks in X-ray diffractogram. In addition, AGZs had various pore structure that may be adhere the suspended solid and offer microbiological niche to decompose organic pollutants. AGZ could remove ammonium, orthophosphate and heavy metals simultaneously. Mixing ratio of artificial zeolite in AGZs was related positively with removal efficiency of $NH_4\;^+$ and negatively with that of $PO_4\;^{3-}$. Root growth of rice seedling was inhibited severely in the mine wastewater because of strong acidity and high concentration of heavy metals. As AGZ(1 kg) stayed in the wastewater(100L) for 4days, water quality turned into safely for agricultural usage and rice seedlings grew normally.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권4호
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• pp.83-89
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• 2015

Soil samples collected in an area of Gahak Mine were investigated for the characterization of mineralogical and physicochemical properties of contaminants in soils. It is found that soils in the study area are contaminated by lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd), in which their concentrations are 595.3 mg/kg, 184.9 mg/kg, 712.8 mg/kg, and 10.64 mg/kg, respectively. All the concentrations exceed the concern criteria of Korean standard. Upon distribution patterns of metals identified by the sequential extraction procedure, our results show that more than 50% of metals are found as a residual type, and 30% are accounted for the association of Fe/Mn oxides. Interestingly, XRD results show that minium (Pb₃O₄) and cuprite (Cu₂O) are identified in the soil samples, suggesting that the sources of the contaminants for Pb and Cu are these minerals. In SEM images, tens of µm of Pb oxides and Pb silicate-minerals are observed. We, therefore, note that the contamination of metals in the study area results from the direct influx and disturbance of tailings. Our findings indicate that the characterization of physicochemical and mineralogical properties of contaminated soils is a critical factor and plays an important role in optimizing recovery treatments of soils contaminated in mine development areas.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2349-2356
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• 2014

The recycling technology by the catalytic conversion is one of the most promising techniques for the $CO_2$ treatment of coal burning power plant flue gases. The conversion of $CO_2$ to valuable product of $CH_4$ can be used as a fuel to run the turbine for electricity generation. Through this technique, the amount of coal needed for the combustion in a gas turbine can be reduced as well as $CO_2$ emissions. Therefore, a series of catalysts based on cerium oxide doped with copper, nickel and manganese were prepared by impregnation method. From the characterization analysis, it showed that the prepared catalysts calcined at $400^{\circ}C$ were amorphous in structure with small particle size in the range below 100 nm. Meanwhile, the catalyst particles were aggregated and agglomerated with higher surface area of $286.70m^2g^{-1}$. By increasing the calcination temperature of catalysts to $1000^{\circ}C$, the particle sizes were getting bigger (> 100 nm) and having moderate crystallinity with lower surface area ($67.90m^2g^{-1}$). From the catalytic testing among all the prepared catalysts, Mn/Ce-75/$Al_2O_3$ calcined at $400^{\circ}C$ was assigned as the most potential catalyst which gave 49.05% and 56.79% $CO_2$ conversion at reaction temperature of $100^{\circ}C$ and $200^{\circ}C$, respectively.