• Resources Recycling
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• v.12 no.1
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• pp.55-64
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• 2003

Presently, the reuse of waste FCC catalysts, which generated from the refining process of crack oil, after the removal of con-taminated metallic impurities have not been attempted domestically yet because the separation technology f3r the impurities from waste catalysts has not been established. As a basic study far the reusable portion from the waste FCC catalysts and treatment of metallic impurities are assured, there will be invoked an significant contribution not only in the recycling of abandoned wastes up to date but also in the treatment efficiency of wastes and extraction of economical benefits from them. The magnetic separation of impurities such as Fe, Ni, and V, from waste FCC catalyst has been attempted with or without its pre-oxidation at high temperature for the purpose of its reuse. The results showed that the separability of impurities by magnetic force was high far non-preoxidized catalysts compared with preoxidized ones, and employment of screen-type matrix showed a higher separation efficiency than ball-type matrix. The separability increased with the strength of magnetic field, and the method of ball matrix has separation efficiency of maximum 51.10%. The amount of metallic impurities was in the decreasing order of V, Ni, and Fe depending upon ICP analysis.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.991-1000
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• 2000

Methanotrophic consortium utilizing methane as the primary carbon source and secreting soluble methane monooxygenase (sMMO) was immobilized on celite R-635 to continuously treat a wastewater containing trichloroethylene (TCE). With influent 2 ppm of TCE. 80.4 and 84.5% of TCE was degraded in 6 and 20 hour of hydraulic retention time (HRT). respectively. and the removal efficiency of TCE was increased with an increase in HRT in methanotrophic consortium biofilm reactor (MCBR). With influent 5 ppm of TCE and 10 hour of HRT. average efficiency of TCE removal was decreased in initial stage. but gradually increased to 81%. TCE was degraded to 88.5 and 96.5% with 10 and 15 hour of HRT. respectively. when methane was supplied alternately with continuous oxygen supply at influent 5 ppm of TCE. The efficiency of TCE degradation was decreased probably because oxidation reaction of methane was proceeded slowly on MMO. when high concentration of methane was supplied with depletion of oxygen. As results of the pilot-scale study. biodegradation of TCE by MCBR system might be feasible at full-scale operation.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.884-889
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• 2018

In this study, polyaniline $(PANI)/WO_3$ electrode was prepared as an anode of a lithium ion capacitor, and its electrochemical characteristics were measured and analyzed. When PANI was electrochemically deposited on the surface of $WO_3$ electrode, the capacity of $PANI/WO_3$ was improved with increase of the deposited amounts of PANI. Furthermore, the effect of light irradiation on capacity and coulombic efficiency was examined by irradiating sunlight during charging and discharging. When the light was irradiated to the $WO_3$ electrode and the $PANI/WO_3$ electrode, those capacities and coulombic efficiencies were increased compared to that measured under the dark condition. It is attributed to the photocatalytic property of $WO_3$ that can generate photoelectrons by light irradiation. In $PANI/WO_3$ electrode, PANI also can be excited under the light irradiation with affecting the electrochemical property of electrode. The photoelectrons improve the capacity by participating in the intercalation of $Li^+$ ions, and also improve the coulombic efficiency by facilitating electrons' transport. Under the dark condition, the capacity of $PANI/WO_3$ was gradually reduced with increase of cycles due to a poor stability of PANI. However, the stability of PANI was significantly improved by the light irradiation, which is attributed to the oxidation-reduction reaction originated from the photogenerated electrons and holes in $PANI/WO_3$.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.1
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• pp.93-101
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• 2017

In this study, the microbubbles were applied to the MBR process for night soil treatment, and the removal efficiency was estimated. As a result of the this study, when the microbubble was supplied directly to the aerobic tank in which the membrane was submerged, excessive scum was generated so could not stable operation of the process. The SS removal efficiencies in the pre-treatment tank were 74.3%, 82.8%, 75.0%, 52.1% on average at the 2 kg, 4 kg, 6 kg, and $8kg\;COD_{Cr}/m^3$, respectively. The mean removal efficiencies were more than 99.4%, 94.0%, 74.1% for SS, $TCOD_{Cr}$, $SCOD_{Cr}$ by MBR process. On the other hand, when the microbubble are directly supplied to the aerobic tank, the microbubble and the scum are attached each other to accelerate the fouling. Therefore, it can be confirmed that stable treatment can be achieved by applying microbubble to the front of the bioreactor for removal of SS and oxidation of organic matters in high concentration organic wastewater treatment such as night soil.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.423-429
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• 2008

Application of manganese-impregnated activated carbon(Mn-AC) in the treatment of synthetic wastewater containing both organic and inorganic contaminants was investigated. Phenol and As(III) was used as representative organic and inorganic contaminants, respectively. When the stability of Mn-AC at acidic condition was evaluated with variation of solution pH ranging from 2 to 4, Mn-AC was unstable below pH 3, while negligible dissolution of Mn was observed above pH 4. This stability test suggests a plausible applicability of Mn-AC in the treatment of wastewater above pH 4. Compared to AC-alone, the adsorption rates of phenol as well as adsorbed amounts of phenol by Mn-AC were slightly decreased due to the decrease of the surface area by impregnation. The maximum adsorbed amount of phenol by Mn-AC was corresponds to 75% of that by AC-alone from the adsorption isotherm study. The oxidation efficiency of As(III) by Mn-AC was greater than that by AC-alone at lower pHs while reverse trend was observed as pH increased above 7. From this work, it was found that Mn-AC could be used in the simultaneous treatment of both phenol and As(III).

• Applied Chemistry for Engineering
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• v.20 no.1
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• pp.87-93
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• 2009

Pd/activated carbon (Pd/AC) and Pd/alumina (Pd/AO) catalysts were prepared by the impregnation of palladium into activated carbon and alumina. The catalytic characteristics according to the kinds of support materials were compared. The decomposition efficiencies of ozone according to kinds of support materials are about the same when these were compared by adding 10 g of catalysts into the water saturated with ozone. The decomposition efficiencies and the oxidation characteristics (TOC, $COD_{Cr}$) of dichloroacetic acid were compared with the ozone only process and the catalytic ozonations using Pd/activated carbon and Pd/alumina catalysts. The decomposition efficiencies of dichloroacetic acid by catalytic ozonations were better than the one by ozone only process, but there was slight difference of the one between Pd/activated carbon and Pd/alumina catalyst. The decomposition efficiency of dichloroacetic acid was increased with increasing ozone dose at a constant concentration of dichloroacetic acid, but the one was little increased with increasing ozone dose at more than 1.0 L/min of ozone dose. It was seemed that the bicarbonate and the chloric ion formed throughout the decomposition of dichloroacetic acid acted as the scavenger of hydroxyl radical.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.145-149
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• 2004

It is necessary for managing a perfect process for degasing aluminum molten metal according to the increase of a grade of aluminum and its alloy products. There are some methods that have been used to manage a degasing process in recent years, such as an injection method that uses aluminum molten metal powder and chemicals supplier and input method that supplies argon and nitrogen, or chlorine gas by using a gas blow-tube. However, these methods show some problems, and it shows that it is a difficult process to handle. pollution due to the producing a lot of toxic gases like chlorine and fluoride gas. irregular effects, and lowering work efficiency due to the excessive processing time. The problems that are the most fatal are the producing a lot of sludge due to the reaction of aluminum molten metal with chemicals. loss of metals, and decreasing the life of refractory materials. In order to solve these problems. this paper develops a technology that is related to aluminum continuous casting molten metal and monolithic degasing apparatus. A degasing apparatus developed in this study improved the exist ing methods and prevented environmental pollution wi th smokeless. odor less, and harmlessness by using a new method that applies argon and nitrogen gas in which the methods used in the West and Japan are eliminated. The developed method can significantly reduce product faults that are caused by the production of gas and oxidation because it uses a preprocessed molten metal with chemicals. In addition. the amount of the produced sludge can also be reduced by 60-80% maximum compared with the existing methods. Then. it makes it possible to minimize the loss of metals. Moreover. the molten metal processing and settling time is also shortened by comparing it with the existing methods that are applied by using chemicals. In addition, it does much to improve the workers' health, safety and environment because there is no pollution. The improvement of productivity and prevent ion effects of disaster from the results of the development can be summarized as follows. It will contribute to the process rationalization because it does not have any unnecessary processes that the molten metal will be moved to an agitator by using a ladle and returned to process for degasing like the existing process due to the monolithic configuration. There are no floating impurities due to the oxidation caused by the contact with the air as same as the existing process. In addition. it can protect the blending of precipitation impurities. Because it has a monolithic configuration. it can avoid the use of additional energy to compensate the temperature decreasing about 60t that is caused by the moving of molten metal. It is not necessary to invest an extra facilities in order to discharge the gas generated from a degasing process by using an agitator. The working environment can be improved by the hospitable air in the factory because the molten metal is almost not exposed in the interior of the area.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1415-1420
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• 2014

Super-critical $CO_2$ ($S-CO_2$) Brayton cycle has been considered to replace the current steam Rankine cycle in Sodium-cooled Fast Reactor (SFR) in order to improve the inherent safety and thermal efficiency. Several austenitic alloys are considered as the structural materials for high temperature $S-CO_2$ environment.. Microstructural change after long-term exposure to high temperature $S-CO_2$ environment could affect to the mechanical properties. In this study, candidate materials (austenitic stainless steels and Alloy 800HT) were exposed to $S-CO_2$ to assess oxidation resistance and the change in tensile properties. Loss of ductility was observed for some austenitic stainless steels even after 250 h exposure. The contribution of $S-CO_2$ environment on such changes was analyzed based on the characterization of the surface oxide and carburization of the materials in which 316H and 800H showed different oxidation behaviors.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.12
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• pp.1268-1272
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• 2008

Low temperature plasma applied with partial oxidation is a technique to produce synthesis gas from methane. Low temperature plasma reformer has superior miniaturization and start-up characteristics to reformers using steam reforming or CO$_2$ reforming. In this research, a low temperature plasma reformer using GlidArc discharge was proposed. Reforming characteristics for each of the following variables were studied: gas components ratio (O$_2$/CH$_4$), the amount of steam, comparison of reaction on nickle and iron catalysts and the amount of CO$_2$. The optimum conditions for hydrogen production from methane was found. The maximum Hydrogen concentration of 41.1% was obtained under the following in this condition: O$_2$/C ratio of 0.64, total gas flow of 14.2 L/min, catalyst reactor temperature of 672$^{\circ}C$, the amount of steam was 0.8, reformer energy density of 1.1 kJ/L with Ni catalyst in the catalyst reactor. At this point, the methane conversion rate, hydrogen selectivity and reformer thermal efficiency were 66%, 93% and 35.2%, respectively.

• Nutrition Research and Practice
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• v.10 no.6
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• pp.629-634
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• 2016

BACKGROUND/OBJECTIVE: The aim of this experiments was to show anti-obesity effects of Korean solar salt from different salt fields in diet-induced obese mice. MATERIALS/METHODS: Diet-induced obesity (DIO) was induced by a high-fat diet (HFD; 45% cal from fat) in C57BL/6J mice for eight weeks. The mice were fed with the designated diets (chow diet for Normal, HFD for Control, 0.47%-salt-mixed HFD for purified salt (PS), Guerande solar salt from France (SS-G), solar salt from Y salt field (SS-Y), solar salts from T salt field (SS-T) and S salt field (SS-S)) for another eight weeks. We checked body weight, food efficiency ratio (FER) and tissue weights (liver and epididymal adipose tissue (EAT)), and observed serum concentrations of triacylglycerol (TG), total cholesterol (TC), leptin and insulin. We also evaluated gene expressions of adipogenic / lipogenic mRNAs of $C/EBP{\alpha}$, $PPAR{\gamma}$ and FAS and beta-oxidation-related factors ($PPAR{\alpha}$ and CPT-1) in liver and EAT. The mineral composition of salt samples were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). RESULTS: SS-T and SS-S significantly reduced body weight gain, FER, and weight of EAT compared to control and other samples (P < 0.05). SS-T and SS-S also significantly decreased serum levels of TG, TC, leptin and insulin (P < 0.05). SS-T and SS-S suppressed expressions of adipogenic / lipogenic mRNAs in liver and EAT, while promoting expression of beta-oxidation-related factors. The lowest sodium concentration was observed in SS-T ($30.30{\pm}0.59%$), and the lowest sodium-to-potassium (Na/K) ratio was found in SS-S (17.81). CONCLUSIONS: Our study shows that well-processed Korean solar salt may have anti-obesity effects in vivo, probably owing to its differences in mineral composition and other components, presumably resulting from the manufacturing processes. Further research is needed into the mechanism and to explore optimal manufacturing processes.