• 한국응용과학기술학회지
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• 제32권3호
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• pp.480-487
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• 2015

In this study, several kinds of active carbons with high specific surface area and micro pore structure were prepared from the coconut shell charcoal using chemical activation method. The physical property of prepared active carbon was investigated by experimental variables such as activating chemical agents to char coal ratio, flow rate of inert gas and temperature. It was shown that chemical activation with KOH and NaOH was successfully able to make active carbons with high surface area of $1900{\sim}2500m^2/g$ and mean pore size of 1.85~2.32 nm. The coin cell using water-based binder in the electrolyte of LiPF6 dissolved in mixed organic solvents (EC:DMC:EMC=1:1:1 vol%) showed better capacity than that of oil-based binder. Also, it was found that the coin cell of water-based binder shows an improved cycling performance and coulombic efficiency.

• 한국재료학회지
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• 제9권4호
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• pp.362-367
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• 1999

We intended to make the activated carbon fibers which could separate, remove and recover the volatile organic compounds of benzene, toluene, acetone and methanol. Changing activation temperature and time, large specific surface area and narrow pore distribution could be obtained. The activated carbon fibers have large adsorption capacity and selectivility for those organic compounds. We characterized the adsorption capability of the activated carbon fibers for benzene, toluene, acetone and methanol by BET specific surface area and pore size and micropore volume measurements. In the result of activation, the maximum value of BET specific surface area of the fibers was $1100\m^2$/g at $800^{\circ}C$ for 60 minutes and $K_2$O was reduced actively in this condition. Their average pore size was 5.8~5.9$\AA$. The activated carbon fibers prepared in this work had high adsorption rate to saturation and the selectibility for the above organic compounds. The adsorbed amount of acetone and methanol(diameter of$ 4.3\AA$ and $4.4\AA$ respectively) which are smaller than micropore diameter in size was 43~49%, which was larger value than benzene and toluene(in the same diameter as $5.9\AA$).

• 자원리싸이클링
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• 제14권1호
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• pp.47-54
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• 2005

본 연구에서는 농산물 폐기물인 국산 포도씨를 원료로 사용하여 roasting, cabonization, chemical activation 과정을 각각 거쳐 활성탄을 제조하였다. 화학적 활성화는 NaOH, KOH, ZnCl$_2$를 활성화제로 사용하였다. 100-300wt%의 중량비율로 활성화하여 제조된 활성탄의 N$_2$-BET 비표면적은 44.09~121.33 m$^2$/g으로 측정되었다. 포도씨 활성탄에 메틸렌 블루를 흡착 시킨 후 UV spectrometer를 사용하여 투광도를 측정하였으며, 투광도 측정 시 메틸렌 블루의 최대 흡광파장은 660 nm로 설정하였다. 그 결과 메틸렌블루의 흡착은 NaOH 활성화제를 사용하여 제조한 활성탄에서 가장 잘 이루어졌으며, 평형 흡착 시간은 60분인 것으로 나타났다.

• 자원리싸이클링
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• 제17권6호
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• pp.68-78
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• 2008

국내에서 대표적으로 버려지는 폐벌목인 잣나무와 리기다소나무를 이용하여 고부가가치 제품으로 활용할 수 있는 활성탄 개발을 위해 활성탄 제조의 최적조건을 측정하였다. 폐벌목 활성탄 제조에 관한 연구는 저온열분해 공정에 의한 폐벌목의 목탄 제조공정과 화학적 활성화 반응을 이용한 목탄의 활성탄 제조공정으로 나누어지며 본 논문은 화학적 활성화 반응을 이용한 목탄의 활성탄 제조공정을 다루고 있다. 일반적으로 활성화제는 알칼리 약품을 이용하고 있으며 본 연구에서는 탄소와 활성화 반응이 잘 이루어지는 KOH와 NaOH를 사용하였다. 실험결과, KOH로 제조된 활성탄이 NaOH로 제조된 활성탄 보다 요오드 흡착력과 비표면적(BET) 등 물성이 우수하였으며 이는 세정공정 후 활성탄의 잔류물이 KOH는 검출되지 않았으나 NaOH는 $3{\sim}4%$의 잔류물이 있는 것으로 보아 목탄과 KOH의 반응이 더 활발함을 알 수 있었다. 일반적으로 잣나무를 이용하여 제조된 활성탄의 물성치가 리기다소나무를 이용한 활성탄 보다 우수함을 알 수 있었다. 목탄과 활성화제의 최적 침적비율은 400 wt.%임을 알 수 있었다 세정방법은 5M 염산용액으로 세척하여 중화시킨 후 증류수로 세정하는 방법이 활성탄의 물성을 높일 수 있었다. 본 연구의 최적 실험조건에서 잣나무를 이용하여 제조된 활성탄의 경우 BET값이 약 $2400\;m^2/g$에 이르렀다.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2002년도 Current Trends in Toxicological Sciences
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• pp.73-73
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• 2002

Thioacetamide has been known to cause immune suppression. The object of the present study is to investigate the role of metabolic activation by flavin- containing monooxygenases (FMO) in thioacetamide-induced immune response. To determine whether the metabolites of thioacetamide produced by FMO causes the immunosuppression, methimazole (MMI), an FMO inhibitor, was used to block the FMO pathway.(omitted)

• Journal of the Korean Wood Science and Technology
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• 제49권4호
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• pp.299-314
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• 2021

본 연구에서는 리그닌 기반 다공성 탄소(lignin-based porous carbon; LBPC)를 수산화칼륨(KOH)으로 활성화할 때 온도가 비표면적과 전기화학적 특성에 미치는 영향을 알아보았다. 리그닌과 acrylonitrile을 그라프트 중합으로 합성한 리그닌-polyacrylonitrile (PAN) 공중합체를 전구체로 하여 LBPC를 제조한 후 LBPC를 KOH로 600, 700, 800, 900℃에서 활성화하여 활성화 처리한 LBPC (KA-LBPC-6, 7, 8, 9)를 제조하였다. KA-LBPC의 표면 특성을 알아보기 위해 주사전자현미경으로 관찰하였으며, 비표면적 분석을 통해 기공 특성을 파악하였다. 전기화학적 특성은 3전극 시스템으로 분석하였다. 실험 결과 SEM 사진상에서 활성화 처리에 의한 미세기공 형성을 관찰하였다. KA-LBPC-7의 비표면적은 2480.1 m²/g, 미세기공 부피는 0.64 cm³/g, 중기공 부피는 0.76 cm³/g으로 KA-LBPC 중에서 가장 좋은 기공 특성을 보였다. 전기화학적 특성 역시 2 mV/s의 주사속도에서 비정전용량이 151.3 F/g이었던 KA-LBPC-7이 가장 좋은 것으로 나타났다.

• 공업화학
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• 제28권6호
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• pp.663-669
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• 2017

활성화제로 KOH, NaOH 및 $ZnCl_2$를 사용하여 폐감귤박으로부터 활성탄을 제조하였다. 최적조건(활성화제의 침적비율 300%, 활성화 온도 : KOH의 경우 $900^{\circ}C$, NaOH의 경우 $700^{\circ}C$, $ZnCl_2$의 경우 $600^{\circ}C$, 활성화 시간 1.5 h)에서 제조한 활성탄을 각각 ACK, ACN 및 ACZ로 명명하였다. 이들 활성탄을 사용하여 회분식 반응기에서 아세톤, 벤젠 및 메틸메르캅탄(MM) 등의 3가지 대상가스에 대한 흡착 특성을 검토하였다. 이들 활성탄에 의한 3가지 대상 가스의 흡착은 Langmuir 모델식보다는 Freundlich 모델식에 더 부합되는 것으로 나타났다. 그리고 흡착 속도실험결과는 유사 1차 속도식보다는 유사 2차 속도식에 잘 부합하였으며, 입자 내 확산 모델 결과는 흡착 과정에서 외부물질전달과 입자확산이 동시에 일어나는 것을 시사해 주었다.

• 한국재료학회지
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• 제23권11호
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• pp.643-648
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• 2013

Activated carbon (AC) was synthesized from rice husks using the chemical activation method with KOH, NaOH, a combination of (NaOH + $Na_2CO_3$), and a combination of (KOH + $K_2CO_3$) as the chemical activating reagents. The activated carbon with the highest surface area (around $2000m^2/g$) and high porosity, which allows the absorption of a large number of ions, was applied as electrode material in electric double layer capacitors (EDLCs). The AC for EDLC electrodes is required to have a high surface area and an optimal pore size distribution; these are important to attain high specific capacitance of the EDLC electrodes. The electrodes were fabricated by compounding the rice husk activated carbons with super-P and mixed with polyvinylidene difluoride (PVDF) at a weight ratio of 83:10:7. AC electrodes and nickel foams were assembled with potassium hydroxide (KOH) solution as the electrolyte. Electrochemical measurements were carried out with a three electrode cell using 6 M KOH as electrolyte and Hg/HgO as the reference electrode. The specific capacitance strongly depends on the pore structure; the highest specific capacitance was 179 F/g, obtained for the AC with the highest specific surface area. Additionally, different activation times, levels of heating, and chemical reagents were used to compare and determine the optimal parameters for obtaining high surface area of the activated carbon.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2001년도 가을 학술발표회 논문집
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• pp.303-305
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• 2001

Porous carbons have beef used as adsorbents, filters, catalyst supports, etc. due to well-development pore structure. Porous carbons can be prepared by two different activation processes i.e. physical activation by steam or CO$_2$, and chemical activation by KOH, H$_3$PO$_4$ etc. from various raw material. Recently, agricultural wastes such as rice hulls [1], coconut shell [2-31 and straws [4] are growing interest as precursors fur porous carbons due to its easy availability and cheapness. (omitted)

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.29.1-29.1
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• 2009

Fabrication of good quality P-type GaN remained as a challenge for many years which hindered the III-V nitrides from yielding visible light emitting devices. Firstly Amano et al succeeded in obtaining P-type GaN films using Mg doping and post Low Energy Electron Beam Irradiation (LEEBI) treatment. However only few region of the P-GaN was activated by LEEBI treatment. Later Nakamura et al succeeded in producing good quality P-GaN by thermal annealing method in which the as deposited P-GaN samples were annealed in N2 ambient at temperatures above $600^{\circ}C$. The carrier concentration of N type and P-type GaN differs by one order which have a major effect in AlGaN based deep UV-LED fabrication. So increasing the P-type GaN concentration becomes necessary. In this study we have proposed a novel method of activating P-type GaN by electrochemical potentiostatic method. Hydrogen bond in the Mg-H complexes of the P-type GaN is removed by electrochemical reaction using KOH solution as an electrolyte solution. Full structure LED sample grown by MOCVD serves as anode and platinum electrode serves as cathode. Experiments are performed by varying KOH concentration, process time and applied voltage. Secondary Ion Mass Spectroscopy (SIMS) analysis is performed to determine the hydrogen concentration in the P-GaN sample activated by annealing and electrochemical method. Results suggest that the hydrogen concentration is lesser in P-GaN sample activated by electrochemical method than conventional annealing method. The output power of the LED is also enhanced for full structure samples with electrochemical activated P-GaN. Thus we propose an efficient method for P-GaN activation by electrochemical reaction. 30% improvement in light output is obtained by electrochemical activation method.