• Resources Recycling
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• v.10 no.6
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• pp.15-21
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• 2001

Shape-controlled copper oxides have been recovered from copper-containing waste etchant by neutralization with alkalihydroxide. Large amount of copper-containing waste etchant is generated from Printed Circuit Board industry. In an environmental and economic point of view, retrieve of the valuable natural resource from the waste is important. In recycling process of copper oxide from the waste etchant, reaction temperature controls shapes and sizes of the products. Copper oxide recovered below reaction temperature $40^{\circ}C$ was of a needle shape, while copper oxide comes in a platy shape above $40 ^{\circ}C$ . Physical properties of samples have been characterized using SEM, XRD, TGA and Atomic absorption spectroscopy.

• Membrane Journal
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• v.26 no.2
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• pp.152-158
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• 2016

The Chlor-alkali (CA) membrane cell is a major electrolysis system to produce valued chemicals such as chlorine gas and sodium hydroxide. The CA membrane process has been attracted in the industries, since it has relatively low energy consumption when compared with other CA processes. The key component in CA process is perfluorinated sulfonic acid ionomer membranes, which provide ion-selectivity and barrier properties to produced gases. Unfortunately, there is limited information to determine which factors should be satisfied for CA applications. In this study, the influences of PFSA membranes on CA performances are disclosed. They include ion transport behaviors, gas evolution capability, and chemical/electrochemical resistances under CA operation conditions.

• Korean Journal of Food Science and Technology
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• v.19 no.5
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• pp.435-440
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• 1987

Gelatinization properties of heat-mositure treated potato and sweet potato starches were investigated. Water-binding capacity of starch was increased by heat-mositure treatment, which was more pronounced in sweet potato starch. Blue value was not affected by the treatment. Amylograph viscosities were decreased by heat-mositure treatment, which was more pronounced in potato starch. Critical concentration of NaOH for gelatinization of starch increased as moisture level increased. Gel volume of starch upon KSCN gelatinization was higher in potato starch. Gelatinized starches showed Binghamapseudoplastic behavior. Consistency index and yield stress were drastically decreased upon heat-moisture treatment.

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.291-297
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• 2007

The hydrolysis reaction of sulfur mustard(HD, bis 2-chloroethylsulfide), one type of the blister agents was studied in water to find the operation conditions which can convert HD into less toxic compounds. The reaction was proceeded into two steps. First, 10~20 wt% of HD was hydrolyzed in water at $90^{\circ}C$ for 2 hr and aqueous sodium hydroxide solution(2.1 eq) was subsequently added to the reaction mixture at room temperature. The efficiency of HD hydrolysis at this experimental conditions was greater than 99.99% and the final degradation products of HD were 68 wt% of thiodiglycol, 8 wt% of 1,2-bis(2-hydroxyethylthio)ethane and 24 wt% of bis(2-hydroxyethylthioethyl)ether.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.531-539
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• 2015

Chlor-alkali industry is one of the largest electrochemical processes which annually producing 70 million tons of sodium hydroxide and chlorine from sodium chloride solution. $DSA^{(R)}$ (Dimensionally Stable Anodes) electrodes such as $RuO_2$ and $IrO_2$, which is popular in chlor-alkali process, have been investigated to improve the chlorine generation efficiency. Although DSA electrode has been developed with various researches, understanding of the chlorine evolution mechanism is essential to the development of highly efficient DSA electrode. In this review paper, chlorine generation mechanisms are summarized and that of key factors are identified to systematically understand the chlorine generation mechanism. Rate determining step, effect of pH, reaction intermediate, and electrode crystal structure were intensively overviewed as key factors of the chlorine mechanism.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.246.1-246.1
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• 2010

본 연구는 바이오가스의 에너지효율성을 높이기 위한 연구로서 바이오가스 정제공정과 초저온액화공정을 통하여 액화바이오메탄을 생산하는 바이오가스 고질화기술개발 연구이다. 바이오가스 정제공정은 탈황, 제습, 흡착, 압축, $CO_2/CH_4$ 분리공정으로 구성하고, 초저온액화공정은 열교환기, $CO_2$ 제거설비, 질소냉매 공급공정으로 구성하여 혐기성소화조에서 발생하는 바이오가스($CH_4$ 농도: 60~65%, $H_2S$: 1,500~2,500ppm)를 $200Nm^3/hr$의 유량으로 인입시켜 액화바이오메탄을 생산하였다. 연구결과, 탈황공정에서는 가성소다 세정법을 이용하여 1,500~2,500ppm으로 인입되는 $H_2S$를 100ppm 이하로 제거한 후, 흡착법을 이용하여 $H_2S$를 완전히 제거하였다. 바이오가스에 포화된 수분은 냉각제습과 흡착제습공정을 통해 Dew point $-70{\sim}-90^{\circ}C$까지 제거하여 안정적으로 $CO_2/CH_4$ 분리공정에 인입시켰다. $CO_2/CH_4$ 분리공정은 흡착방식을 적용하여 $CH_4$ 순도가 95% 이상인 바이오메탄을 생산하였으며, 이때 메탄 회수율은 약 87%이였다. $CO_2$가 분리된 바이오메탄은 초저온액화공정을 이용하여 액화바이오메탄으로 전환시켰다. 이때 초저온액화공정은 Reverse Brayton cycle로 구성하였으며, 냉매로는 질소를 사용하였다. 액화바이오메탄의 생산은 바이오메탄을 등엔트로피과정인 단열팽창을 통하여 $-155{\sim}-159^{\circ}C$의 초저온으로 냉각되는 질소냉매와 열교환기에서 열교환시켜 이루어졌으며 그 생산량은 $3.46m^3$/day(1bar, $-161^{\circ}C$)이었다.

• Clean Technology
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• v.11 no.2
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• pp.57-67
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• 2005

Epoxy resins are produced by the dehydro condensated reaction with ECH (Epichlorohydrin) and BPA(Bisphenol-A) as raw reactants under sodium hydroxide(NaOH) as a catalyst, and from this reaction, salted water named of brine, which contains ECH derivatives in condition of emulsion as likely as glycidol and polymer resins, is produced as an undesired side product. This brine water is alkaline wastewater and causes process fouling problems by plugging and chemically depositing polymer particles on the surface of inner wall of reactors and pipes, and decreases the biodegradable efficiency in the wastewater process. In this study, the optimization of coagulation and sediment reactions, using inorganic and organic polymer coagulants, were performed to remove the causes occurring the process fouling phenomena. And also, based on this study, the methodologies applicable to the commercial processes including economical analysis were presented.

• Resources Recycling
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• v.19 no.4
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• pp.13-18
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• 2010

Effort of reducing wastes and their recycling is increasing in worldwide. Especially, extreme care for alkali recycling is required because of its environmental pollution and its corrosive characteristics. In order to manage alkali wastes effectively, it is necessary to make quality standards for recycling products from the alkali wastes because there are no quality specifications yet. In this study, we selected several recycling candidates from the alkali wastes based on the analysis of the most recent data of the various industrial sites. As a result, the recycling candidates from the alkali wastes are sodium hydroxide, aluminum sulfate, poly aluminum chloride. It is believed that the proper management system for waste products is required in governmental point of view and it propagates positively for resolving various environmental issues.

• Polymer(Korea)
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• v.24 no.6
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• pp.869-876
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• 2000

In order to improve the cell-compatability of poly(L-lactide-co-glycolide) (75 : 25 by mole ratio of lactide to glycolide, PLGA) surfaces, the physicochemical treatments have been demonstrated. Chemical treatments were 70% perchloric acid. 50% sulfuric acid and 0.5 N sodium hydroxide solution and physical methods were corona and plasma treatment. The water contact angle of surface treated PLGA decreased from 73$^{\circ}$ to 50~60$^{\circ}$, i.e., increased hydrophilicity, due to the introduction of oxygen-containing functional group onto PLGA backbone by the measurement of an electron spectroscopy for chemical analysis. It could be observed that the adhesion and growth of fibroblast cell on physicochemically treated PLGA surfaces, especially perchloric acid treated PLGA surface, were more active than on the controt. In conclusion, it seems that surface wettability as hydrophilicity of PLGA plays an important role in cell adhesion, spreading and growth.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.04a
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• pp.193-197
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• 2001

본 연구에서는 국산닥, 태국닥, 중국닥의 원료를 사용하여 펄핑, 표백, 고해, 초지, 건조의 방식을 변화시켜 총 3500 여장에 이르는 한지를 한지제조 전문가가 일정한 방법에 따라 제 조하였고 그 특정들을 조직적으로 검토하였다. 이러한 연구는 한지의 물성이 닥섬유의 처 리공정에 의해 어떻게 영향을 받는지 연구를 통계적으로 가능하게 하였다. 본 연구에서는 육재펄핑과 일광표백의 효과, 외발뜨기와 쌍발뜨기의 효과, 고해방식의 차이, 먹퍼집성에 대 해 결과들을 보이 고 있다. 육재 펄핑과 일광표백이 한지의 물성에 어떠한 영향을 미치는지 알아보기로 하였다. 현 재는 많은 한지 업자들이 육재펄핑보다는 가성소다 펄핑 (그림에서는 약품펄핑으로 표기), 일광표백보다는 차아염소산 나트륨 (그림에서는 약품표백으로 표기)을 사용하는 것이 보통 이다. 육재펄핑과 일광표백을 실시한 한지는 열단장, 인열강도, 내절도를 약품펄핑이나 약 품표백보다 높이는 효과가 있음을 알 수 있었다. 하지만 약품을 사용하는 경우 리그닌의 용출이 더 수윌하므로 백색도는 약품을 사용하는 경우가 더 유리하였다. 국산닥의 경우 육 재펄핑과 일광표백을 한 경우 먹퍼짐성이 약품사용 한지보다 크지 않음을 볼 수 있었다. 한국의 전통적인 외발뜨기 초지방식은 일본의 쌍발뜨기 방식에 비해 많은 물리적 우수성 을 보이고 있다. 외발뜨기가 쌍발뜨기에 비해 열단장, 신장율, 인열지수 및 내절도 모두가 우수함을 잘 보이고 있다. 섬유의 성질과 관련하여 전체적으로 조명해 보면, 열단장, 인열 지수는 국산닥이 가장 높으며, 내절도는 태국닥이 우수하였고, 중국닥의 경우 모두 매우 불 량함을 알 수 있다. 이것은 아마도 처리중에 과도한 표백을 실시하지 아니하였는가 하는 의구심을 들게한다. 열단장과 신장율 역시 국산닥이 우수하였다. 글씨를 쓸 때, 붓이 나가 는 정도를 마찰게수로 짐작해 보았다. 동 마찰계수와 정 마찰계수는 국산닥이 낮은 편이였 다. 마찰계수가 낮다는 사실은 한지의 표면이 더 매끄럽다고 표현될 수 있는데, 역시 국산닥 으로 제조한 한지가 붓이 나가는데 유리하지 않을까 하는 추측을 할 수 있다. 본 실험결과 는 한지 사용자들의 느낌과 상관관계를 얻어내어서 확인해야 할 것이다. 닥방망이로의 고해나 칼비터에 의한 고해나 큰 물성적으로 큰 차이를 보이지는 않고 있 었다. 단지 섬유의 차이가 고해방식의 차이보다 월등히 크다는 사실을 보이고 있다 이러한 점은 섬유장의 길이에서도 볼 수 있다. 칼비터가 섬유를 절단하기만 하고 닥방망이 고해가 섬유장의 변화를 일으키지 않는다면 틀림없이 평균 섬유장의 차이가 생길것이다.