• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.47-54
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• 2021

In this study, the performance of a honeycomb-type hydrogen oxidation catalyst to remove hydrogen in a hydrogen economy society to secure leaking hydrogen. The Pd/TiO₂ catalyst was prepared based on a liquid phase reduction method that is not exposed to a heat source, and it was showed through H₂-chemisorption analysis that it existed as very small active particles of 2~4 nm. In addition, it was found that the metal dispersion decreased and the active particle size increased as the reduction reaction temperature increased. It was meant that the active metal particle size and the hydrogen oxidation performance were in a proportional correlation, so that it was consistent with the hydrogen oxidation performance reduction result. The prepared catalyst was coated on a support in the form of a honeycomb so that it could be applied to the hydrogen industrial process. When 20 wt% or more of the AS-40 binder was coated, oxidation performance of 90% or more was observed under low-concentration hydrogen conditions. It was showed through SEM analysis that long-term catalytic activity can be expected by enhancing the adhesion strength of the catalyst and preventing catalyst desorption. It is a basic research that can secure safety in a hydrogen society such as gasification, organic resource, and it can be utilized as a system that can respond to unexpected safety accidents in the future.

• Journal of Conservation Science
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• v.36 no.3
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• pp.213-224
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• 2020

This research conducted a component analysis and conservation treatment of "Sangryangmun," a material which had been written in 1965 and was discovered during the repair project for "Jinnamgwan" in Yeosu. The "Sangryangmun" has been stored in a cylindrical metal storage; however, defects, discolorations, hardening, and damages caused by pollutants were found. Based on the XRF analysis, rust in the cylindrical metal storage, which was made of Cu, was stuck on the surface of the "Sangryangmun". Using FT-IR and Pyrolysis-GC/MS analyses, carbonyl and compounds of fatty acids were detected; the organic material on the surface of the "Sangryangmun" was identified to have belonged to oil-based components. Therefore, it was presumed that the bast fibers of a mulberry was used in the paper. To determine the conservation materials, component analysis, condition survey, and preliminary test on adhesives were conducted. Moreover, the missing parts and partial linings were filled using mulberry-fiber paper, methyl cellulose, etc.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.47-52
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• 2010

Physical, chemical and biological properties of soils and cadmium(Cd) content of Artemisia princeps var. orientalis collected from 10 metalliferous mines were analysed. Cd contents of unplanted soils and rhizosphere soils were not significantly different(p < 0.05), and mean values were 5.92 and 5.91 mg/kg, respectively. In addition, Cd content of rhizosphere soils were correlated with Cd content of Artemisia princeps (p < 0.05, ${R^2}_{shoot}$ = 0.3120, ${R^2}_{root}$ = 0.4177). Minimum data set(MDS) of soil quality parameters for statistical assessment of Cd uptake was established by principal component analysis, and it was identified as organic matter(OM), dehydrogenase activity(DHA), pH, exchangeable Mg. According to multiple regression analysis using the MDS, coefficients of determination ($R^2$) for Cd uptake of shoot and root of Artemisia princeps were found to be 0.3418 and 0.5121, respectively. This suggests that statistical soil quality assessment using the MDS seems a useful tool to interpret heavy metal uptake of plant.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.2
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• pp.66-70
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• 2001

In this study farm soil was tested under artificial acid rain(pH = 5.34), which is average pH of Pusan metropolitan area. and to find out the soil's acid neuralization capacity, soil acidity, CEC(cation exchange capacity)and akaline meatals, such as K, Ca and Na were tested. Because oyster shells(OS) had portion of alkaline metals, OS could play a role in acid soil amendment. And soil addition of sewage treatment sludge(STS) could be a alternative for disposal method. The purpose of this study is to evlauate acid soil amendment using STS and OS. In case of soil and STS, mixing ratio was10:0, 9:1, 8:2, 7:3. And STS mixed OS was also added in acid soil as same ratio as STS. Throught the experiment, soil acidity was stationary state with slight decrease, and CEC was also stationary state but with slight increase. Allkaline metals showed differences in concentration, but all of them were tend to decrease. In conclusion, STS mixed OS could play a part in amendment of acid soil.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.05a
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• pp.11-11
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• 2009

종래의 산업폐수 처리기술로는 중금속 함유 폐수에 수용성의 금속염을 첨가하여 가성소다 혹은 소석회를 이용하여 pH를 조정하고 고분자 응집제를 첨가하여 금속의 수산화물을 생성시켜 이를 부상 혹은 침전시켜 Sludge화하여 제거하는 방법이 주로 사용되고 있다. 그 외 질소, 인, 유기물이 함유된 폐수의 경우에는 Biological Oxidation Techniques, 활성탄 흡착방식이 주로 채택되고 있다.[1-3] 이러한 폐수처리기술은 화학약품 사용량이 과다하고 이는 Sludge 생성량을 증대하고 2차 폐수처리가 필요로 하는 경우가 많고, 처리장이 면적이 넓어야 하고 대용량의 Sludge 제거창치가 필요하여 고비용의 처리공정으로 문제점을 가지고 있다.[2-3] 이에 본 연구에서는 이러한 기존 기술의 문제점을 보완할 수 있고 기존 기술로는 완벽하게 처리하기 곤란한 악성 폐수들에 대한 새로운 고도처리기술로 초전도 마그네트를 이용한 고구배 자기분리기술에 대한 기초연구를 하였다. 본 연구에서 사용한 고구배 자기분리 시스템은 무헬륨 전도냉각방식으로 자기분리를 위해 사용한 필터는 SUS 430 재질의 메쉬 형태로 제작하여 실험하였다. 또한, 자기분리 처리를 위한 전처리 공정으로는 응집제를 첨가하여 자기분리 효율을 높이고자 하였다. 자기분리 처리대상수로는 포항제철에 압연 강판에 사용되는 냉각수를 대상으로 자기분리 처리에 대한 효과를 실험하였다. 또한, 자기분리에 대한 특성을 평가하기 위해 강자성의 $Fe_3O_4$ 미세자성분말을 첨가하여 처리수내의 들어있는 유기물질에 대해 자기분리 자장 및 유속에 대한 처리효율을 미치는 영향을 조사하였다. 자기분리 처리는 1~6 Tesla에서 자기필터는 디스크 형태로 다층으로 연속적으로 적층하였으며, 처리유속은 1~4 l/min으로 하였다. 고농도인 처리폐수를 자가분리 인가 자장에 따라 처리하여 고농도에서는 70%, 저농도에서는 98 %까지 처리되었다. 또한, 자기분리용 필터는 SUS 430 재질의 mesh 망을 사용하였으며 인가자장 및 유속변화에 대한 실험 결과 탁도 및 농도는 필터 크기의 영향은 거의 차이가 없었으며 단지 인가자장 및 유속에 따라서 지수적으로 감소하였다. 자기분리된 용액 내 $Fe_3O_4$ 입도 분석 결과 자기분리 이전에 분포하던 $10\sim20\;{\mu}m$의 입자는 거의 제거되었으며 2 ${\mu}m$ 이하의 입자들은 실험 횟수에 따라 점점 직경이 작은 쪽으로 분포가 좁아졌으며, 마그네타이트의 자화율을 분석한 결과 약 0.8 Tesla에서 포화 되었으며 처리수의 탁도 및 농도가 자장에 따라 감소하는 것으 알 수 있었다.

• 한국해양학회지
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• v.26 no.3
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• pp.193-203
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• 1991

KODOS (Korea Deep ocean Study)-89 sediments, recovered from western part of Clarion-Clipperton fracture zone in north Pacific, show two distinctly colored layer zones: surface yellow brown layer (unit A) and subsurface dark brown layer (unit B), and roughly recognized as Quaternary and Tertiary in age, respectively. Geochemical characteristics are also different in those two units. Smectite, water, micronodule, and heavy metal contents are higher in unit B, while POC content is higher in unit A. High smectite and low POC contents in unit B are due to the longer formation period of smectite, almost decomposition of labile organic matter in unit B relative to unit A. High water content in unit B is caused by coarse fabric which results from higher content of spicules and spines. Additionally, stronger electrostatic repulsion force caused by high smectite content also supports high water content in unit B relative to unit A. Variations in heavy metal contents are closely related to the amount of micronodule, which has higher metal contents than that of sediment. Therefore, we conclude that the differences of geochemical characteristics in unit A and unit B are resulted from the different diagenetic durations of unit A and unit B.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.438-445
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• 2017

Tanzania has abundant copper deposits, but copper-metal extraction remains low there, owing to the lack of suitable copper recovery processes and insufficient funds for developing mining technologies. Accordingly, leaching and solvent extraction methods for the extraction of copper from copper ore were studied with a particular emphasis on developing a simple processing method for small-scale copper mining. Chrysocolla ore was used as the copper-bearing mineral and sulfuric acid was used as the leaching reagent. A maximum copper recovery of 95.1% was obtained when the particles in the sample were smaller than $53{\mu}m$, the concentration of 98%(w/w) sulfuric acid in the leaching solution was 5.0 g/L and the stirring rate was between 60 and 80 rpm. The highest selectivity of $Cu^2+$ in the solvent extraction was obtained using 15% LIX-70 in kerosene. In the pH range from 0.5 to 3.0, the efficiency of $Cu^2+$ extraction increased with increasing pH. However, at pH values higher than 3.0, other metal ions were extracted into the organic phase more readily than $Cu^2+$. The highest solvent extraction rate obtained was 96.5% at pH values of 2.0 and 3.0 using 15% LIX-70.

• Korean Journal of Heritage: History & Science
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• v.48 no.1
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• pp.44-61
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• 2015

The research on the conservation of the movable modern and contemporary cultural heritage have been actively performed internationally since late 20th century. In this study, the international research trends of movable modern and contemporary cultural heritage conservation in last decades were analyzed. Setting up the range of the period, research papers were collected through various databases based on the systematic literature review process. Samples of 45 domestic papers and 505 foreign papers were classified by materials as books and paper, metals, textiles and fibers, photographs and audio-visuals, woods, plastics and ceramics and glass. The types of treated artifacts, detailed materials of the treated artifacts, and the research subjects were investigated from each paper. The data were compiled statistically and analyzed. Number of papers are published domestically in the book and paper conservation and metals conservation fields, but there are needs for more diversified artifact types and extensive research subjects. The researches in foreign countries are active in conservation of organic materials such as paper, textile and photographs and deal with various research subjects on not only treatment techniques and elemental analysis but also preventive conservation and conservation ethics. It is expected that this study would contribute to the field as a preliminary data on the conservation of modern and contemporary cultural heritage.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.59-66
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• 2022

Lithium-ion batteries have greatly expanded along with the mobile phone market, and as the electric vehicle business is activated in earnest, they will attract many people's attention even afterwards. Until now, many people have attracted attention to the recovery of valuable metals inside lithium-ion batteries, but graphite, which is mainly used as an anode material, is also worth recycling. Therefore, in order to recover graphite with high purity and valuable metals, graphite that can be used as an anode material of a secondary battery may be generated again through a regeneration process of purifying and separating graphite from a waste lithium-ion battery and recovering electrical characteristics of graphite. This paper describes the process of converting waste graphite into regenerated graphite and the environmental and economic effects of regenerated graphite.

• Analytical Science and Technology
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• v.18 no.2
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• pp.112-119
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• 2005

This study reports on the efficiency of cleaning enameled magnet wire using a sulfuric acid $H_2SO_4$ and removal of dissolved organic material using hydrogen peroxide $H_2O_2$ and nitric acid $HNO_3$ at $80^{\circ}C$. The method involves the addition of pure $H_2SO_4$ and $H_2O_2$ or $HNO_3$. Layers of enameled organic material were dissolved by 90% $H_2SO_4$ and the solution was maintained as 35% $H_2O_2$ or 60% $HNO_3$. $H_2O_2$ content in aqueous $H_2O_2$ was maintained as 8.8 : 1.0. An initial concentration of $H_2SO_4$ in dissolution conditions was accomplished within 15 min, with a stripping time of about 2 h. The concentrations of $H_2O_2$ and $HNO_3$ in the processing bath were relatively low, but sufficient enough to produce an effective amount of power in the bath for the removal of the enamel material. The cleaning effect of enameled organic material involves the dehydration by $H_2SO_4$ and the oxidation by $H_2O_2$ or $HNO_3$.