• 한국표면공학회지
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• 제57권2호
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• pp.92-97
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• 2024

The LiBr aqueous solution, which is the absorption liquid of absorption refrigerator, must be replaced periodically because the concentration of impurities such as Cu²⁺, Fe²⁺, Ca²⁺, etc., increases due to corrosion of the tubes as the period of use increases, and the refrigeration efficiency decreases significantly. In order to reuse the waste absorption liquid, flocculation-precipitation method is mainly applied to precipitate the impurities, which requires hundreds of times the concentration of impurities and generates additional waste. In this study, a process for removing Cu ion impurities from cyclone electrolyzer by electrolytic reduction is presented in a small-scale facility without additional waste. It was confirmed that Cu ion impurities can be removed down to 1 ppm by electrolytic reduction process, and to further improve the removal rate, the mass transfer rate was increased by using a cyclone electrolyzer. The removal rate of Cu ions increased with the increase of flow rate and current density, and it was confirmed that Cu was removed at a rate of 1.48 ppm/h under the condition of 330 mL/sec and 2.5 mA/cm².

• 한국재료학회지
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• 제16권2호
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• pp.80-84
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• 2006

The removal efficiency of Cu and Fe contaminants on the silicon wafer surface was examined to investigate the effect of cleaning solutions on the behavior of metallic impurities. Silicon wafers were intentionally contaminated with Cu and Fe solutions by spin coating and cleaned in different types of cleaning solutions based on $NH_4OH/H_2O_2/H_2O\;(SC1),\;H_2O_2/HCl/H_2O$ (SC2), and/or HCl/$H_2O$ (m-SC2) mixtures. The concentration of metallic contaminants on the silicon wafer surface before and after cleaning was analyzed by vapor phase decomposition/inductively coupled plasma-mass spectrometry (VPD/ICP-MS). Cu ions were effectively removed both in alkali (SC1) and in acid (SC2) based solutions. When $H_2O_2$ was not added to SC2 solution like m-SC2, the removal efficiency of Cu impurities was decreased drastically. The efficiency of Cu ions in SC1 was not changed by increasing cleaning temperature. Fe ions were soluble only in acid solution like SC2 or m-SC2 solution. The removal efficiencies of Fe ions in acid solutions were enhanced by increasing cleaning temperature. It is found that the behavior of metallic contaminants as Cu and Fe from silicon surfaces in cleaning solutions could be explained in terms of Pourbaix diagram.

• 한국진공학회지
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• 제10권2호
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• pp.267-274
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• 2001

원격 수소 플라즈마에 의한 Si 웨이퍼 표면 위의 Cr, Ni 및 Cu불순물의 제거 효과를 조사하였다. Si 웨이퍼를 이 불순물들이 포함되어 있는 아세톤으로 집중적으로 오염시켰으며 최적 공정조건을 결정하기 위해 rf-power와 plasma노출시간을 변화시키면서 실험을 수행하였다. 리모트 수소 플라즈마 세정 후 Si 웨이퍼 표면은 Total X-ray Reflection Fluorescence(TXRF), Surface Photovoltage(SPV) 및 Atomic Forece Microscope(AFM)에 의해 분석되었다. 리모트 수소 플라즈마 세정 후 Cr, Ni 및 Cu불순물의 농도는 감소하였고 소수 전하운반자수명은 전반적으로 증가하였다. 또한 AFM 분석결과 표면 거칠기는 전반적으로 향상되었고 Si 기판에 거의 손상을 주지 않았다. TXRF 분석결과는 리모트 수소 플라즈마 세정이 적절한 공정 조건에서 이루어질 때 금속 오염물의 제거에 아주 효과적임을 보여주었다. 또한, Cr, Ni 및 Cu 불순물의 제거는 $SiO_2$가 제거될 때 $SiO_2$에 묻어 함께 제거되는 이른바 lift-off mechanism에 의한 것으로 사료된다.

• 산업기술연구
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• 제10권
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• pp.83-88
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• 1990

The samples used for this work were low grade c1ay($Fe_2O_3$ : 2.90%, $TiO_2$ : 1.65%) produced from Youngsan-po district, and for the iron-bearing impurities removal having a bad influence on Kaoline sample was carried out column floatatoin using Oleic acid, Potassium oleat, Aero 840 promotor, Aero 870 promotor and Keroseneas collectors. For removal of the iron-vearing impurities from the kaoline, investigated first chemical composition size distribution of Kaoline sample, also performanced a basic study on pulp density, collector and pH change on a sort of frother. The flotation separation of impurities from kaoline can be achieved by using both oleic acid and Aero 840 promotor as collectors within narrow acid limits(pH 2-3). Pine oil was more effective frother than MIBC with olelic acid as aa collector.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.405-406
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• 2012

• Environmental Engineering Research
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• 제24권2호
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• pp.181-190
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• 2019

Constructed wetlands are improvised man-made systems, designed for adopting the principle of natural wetlands for purifying wastewater - the elixir of life. They are used widely as a cost-effective and energy-efficient solution for treating greywater generated from different tertiary treatment sources. It provides an elaborate platform for research activities in an attempt to recycle earth's natural resources. Among the several organic impurities removal mechanisms existing in constructed wetland systems, the earth's active microbial population plays a vital role. This review deals with the recent advancements in constructed wetland systems from a microbiological perspective to (effect/ devise/ formulate) chemical and physical treatment for water impurities. It focuses on microbial diversity studies in constructed wetlands, influence of wetland media on microbial diversity and wetland performance, role of specific microbes in water reuse, removal of trace elements, some heavy metals and antibiotics in constructed wetlands. The impurities removal processes in constructed wetlands is achieved by combined interactive systems such as selected plant species, nature of substrate used for microbial diversity and several biogeochemical effected reaction cycles in wetland systems. Therefore, the correlation studies that have been conducted by earlier researchers in microbial diversity in wetlands are addressed herewith.

• 자원리싸이클링
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• 제20권1호
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• pp.61-68
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• 2011

산세척을 통해 금속급 실리콘을 정련하기 위해 황산, 질산, 염산과 불산의 혼산 용액을 사용하여 $50^{\circ}C$에서 불순물의 제거 거동을 조사하였다. 금속급 실리콘에 함유된 불순물중 붕소는 산세척으로 제거되지 않았고, 농축효과로 인해 처리 후 농도가 종가하였다. 본 실험범위에서 인은 약 60% 정도 제거되었다. 황산과 질산용액으로 처리시 주요 불순 금속의 제거율은 50% 미만으로 정련 효과가 크지 않았다. 염산과 불산의 혼산으로 산세척하면 주요 불순 금속이 90% 정도 제거되었다. 각 산세척조건에서 얻은 실리콘의 순도와 주요 불순 금속들의 제거율에 대한 자료를 제시하였다.

• 한국염색가공학회지
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• 제10권1호
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• pp.43-50
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• 1998

In order to investigate the effect of contained impurities of polyester fiber fabric on the scouring and dyeing property, 3 kinds of polyester fabrics were heat-set treated at $160-200^\circ{C}$ and evaluated its scouring and dyeing property by through with soxhlet extraction and K/S value of the dyed fabric derived from the surface reflectance. The impurities such as oiling and sizing agent are adhered more strongly on the polyester fabric surface by heat setting temperature. In scouring test, the removal of the these re-adhered impurities on the polyester fabric is very difficult in comparing with unheat-set treated polyester fabric. It is also confirmed that the remained impurities on the polyester fiber decreased its dyeing property.

• 자원리싸이클링
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• 제29권6호
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• pp.57-64
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• 2020

본 연구에서는 LCD 터치 패널 유리의 재활용을 위해 기계적 방법과 화학적 용해법을 혼용하여 OCA 및 유기 불순물을 제거하는 실험을 진행하였다. 터치 패널의 기계적 파분쇄를 위해 cut mill과 oscillation mill을 이용하였으며, OCA와 유기 불순물의 제거를 위해 물, 에탄올, 디클로로메탄을 이용하여 터치 패널 파쇄물을 세정하였다. 세정 이후 TGA를 통해 유기 불순물의 제거 효율을 평가한 결과 디클로로메탄 단일 용매를 사용한 경우 세정 효과가 가장 뛰어났으며, 세정 온도가 증가함에 따라 유기 불순물의 제거 효과가 증가함을 확인하였다. 제타 전위 측정을 통해 터치 패널 유리 파쇄물의 용매 내 분산도를 평가한 결과, 세정 효과가 가장 낮은 물의 제타 전위 절대값이 타용매에 비해 낮았으며, 유기물의 제거 효과는 화학적인 용해 특성뿐 아니라 용매 내 물리적인 분산 특성에 의해서도 영향을 받을 수 있음을 확인하였다.

• 한국분말재료학회지
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• 제9권4호
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• pp.235-244
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• 2002

The effects of residual impurities on solid state sintering of the powder injection molded (PIMed) W-15wt%Cu nanocomposite powder were investigated. The W-Cu nanocomposite powder was produced by the mech-ano-chemical process consisting of high energy ball-milling and hydrogen reduction of W blue powder-cuO mixture. Solid state sintering of the powder compacts was conducted at $1050^{\circ}C$ for 2~10 h in hydrogen atmosphere. The den-sification of PIM specimen was slightly larger than that of PM(conventional PM specimen), being due to fast coalescence of aggregate in the PIM. The only difference between PIM and PM specimens was the amount of residual impurities. The carbon as a strong reduction agent effectively reduced residual W oxide in the PIM specimen. The $H_2O$ formed by $H_2$ reduction of oxide disintegrated W-Cu aggregates during removal process, on the contrary to this, micropore volume rapidly decreased due to coalescence of the disintegrated W-Cu aggregates during evolution of CO.It can be concluded that the higher densification was due to the earlier occurred Cu phase spreading that was induced by effective removal of residual oxides by carbon.