• Corrosion Science and Technology
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• 제9권6호
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• pp.281-288
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• 2010

This study examined the carbon corrosion at Pt/C interface in proton exchange membrane fuel cell environment. The Pt nano particles were electrodeposited on carbon substrate, and then the corrosion behavior of the carbon electrode was examined. The carbon electrodes with Pt nano electrodeposits exhibited the higher oxidation rate and lower oxidation overpotential compared with that of the electrode without Pt. This phenomenon was more active at $75^{\circ}C$ than $25^{\circ}C$. In addition, the current transients and the corresponding power spectral density (PSD) of the carbon electrodes with Pt nano electrodeposits were much higher than those of the electrode without Pt. The carbon corrosion at Pt/C interface was highly accelerated by Pt nano electrodeposits. Furthermore, the polarization and power density curves of PEMFC showed degradation in the performance due to a deterioration of cathode catalyst material and Pt dissolution.

• 한국식품영양과학회지
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• 제43권4호
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• pp.564-569
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• 2014

Benzo(a)pyrene 함량이 4.1 ppb가 되도록 첨가한 참기름에 흡착제인 활성탄을 첨가하였을 때 첨가량, 교반시간, 교반온도가 증가함에 따라 benzo(a)pyrene 함량이 줄어들었다. 참기름에 활성탄을 0.5%(w/w) 투입하고, 30분간 $70^{\circ}C$에서 교반하였을 때 볶은 참기름에 존재하고 있는 benzo(a)pyrene의 함량은 0.91 ppb까지 낮아져 식품공전규격인 2.0 ppb 이하의 적합 수준의 참기름을 얻을 수 있었다. 경기권 재래시장에서 판매되고 있는 재래식 압착 참기름 30건의 benzo(a)pyrene의 함량은 0.19 ppb부터 4.11 ppb로 나타났다. 경기권 재래시장에서 구입한 참기름 중 benzo(a)pyrene 함량이 가장 높은 3가지 시료(2.14~4.11 ppb)를 위와 같은 최적의 흡착조건으로 처리하였을 때 benzo(a)pyrene의 함량은 0.43~0.86 ppb로 매우 효과적으로 감소하였다. 본 연구는 활성탄 첨가 후 교반처리만으로 볶음공정을 반드시 거치는 참기름에서 규격 이상의 벤조피렌이 검출되는 것을 저감화 하는 방법을 제시함으로써 참기름이 안전하게 생산, 유통될 수 있는 데에 응용할 수 있을 것으로 생각된다.

• 한국세라믹학회지
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• 제42권1호
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• pp.56-61
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• 2005

아나타제 $TiO_{2}$, 활성탄, 세라믹섬유를 포함하는 VOC 흡착과 광산화분해 특성을 동시에 갖는 내구성이 우수한 광촉매 종이를 제조하여 그 특성을 분석하였다. 광촉매 종이 제조용 슬러리 내에 함유되어 있는 $TiO_{2}$를 활성탄 및 세라믹섬유 표면에 선택적으로 결합시키기 위한 PDADMAC의 적정농도범위는 $10{\~}15ppm$이었으며, 제지방법에 의해 만들어진 광촉매 종이는 두께 0.4mm, 평량 $380g/m^{2}$을 나타내었다. 제조된 광촉매 종이는 활성탄에 의한 흡착과 $TiO_{2}$에 의한 광산화 분해 반응이 동시에 진행되어 이들 두 반응이 각각 단독으로 진행되는 VOC 제거용 소재에 비하여 아세트알에히드의 제거속도를 크게 증가시켰다. 또한 세라믹섬유-$TiO_{2}$, 활성탄-$TiO_{2}$의 선택적인 결합은 UV 조사시 $TiO_{2}$에 의한 기지내 유기물의 분해를 방지하여 내구성을 개선하는데 효과적이었다.

• 한국식품저장유통학회지
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• 제16권1호
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• pp.75-81
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• 2009

옥수수기름의 제조공정 단계별 공정유 및 이 과정에서 발생되는 부산물에 함유되어 있는 B(a)P 함량을 측정하고 이의 제거방안에 대하여 연구하였다. 옥수수기름에서 높은 수준의 B(a)P가 검출되는 원인은 옥수수에 함유되어 있는 B(a)P의 80% 이상이 옥수수 배아에 집중적으로 분포하는데 따른 현상이었다. 이로부터 얻어진 원유를 일반적인 정제공정을 거칠 경우 최종 탈취유에서는 $2.15{\mu}g$/kg가 검출 되었다. 따라서, 옥수수기름에서 일반적인 정제공정에 의해서는 현행 우리나라의 식용유 중 B(a)P 함유량 $2.0{\mu}g$/kg 이하의 법적 규격을 충족시키기 어려움을 쉽게 알 수 있었다. 이에 탈색공정에서 사용하는 2%(w/w) 내외의 산성백토 대신 산성백토:활성탄소=90:10(w/w)의 혼합분을 처리하여 $0.09{\mu}g$/kg 수준의 탈취유를 얻을 수 있었다. 이 때, 활성탄소의 처리량은 산성백토 대비 10% (w/w) 수준이 적정하였으며, 이의 증가에 따른 B(a)P 제거율 증가는 기대하기 어려웠다. 처리하는 활성탄소의 입도가 B(a)P 제거에 미치는 영향이 컸는데, $50{\sim}100$ mesh 수준의 입도를 갖는 것이 최적의 조건임을 확인하였다.

• Carbon letters
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• 제22권
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• pp.110-114
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• 2017

• 한국미생물·생명공학회지
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• 제27권6호
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• pp.433-439
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• 1999

Among microorganisms isolated from soil, YJ-66 strain was the best producer of flocculant and was examined for flocculating ability in the active carbon and CaCl2. YJ-66 strain was the best producer of flocculant and was examined for flocculating ability in the active carbon and CaCl2. YJ-66 strain was identified to be a species belonging to the genus Achromobacter. The optimum culture condition for production of bioflocculant with the isolated strain was for 72hrs at 3$0^{\circ}C$ and pH7.5. The favorable carbon, nitrogen sources and inorganic salts for production of the flocculant were sucrose, peptone, MgSO4 and KH2PO4, whose optimal concentrations were 2%. 0.067%, 0.1% and 0.1%, respectively. Addition of the carbon and inorganic salts significantly increased the production of flocculant. Compositions of optimized culture medium for bioflocculant production by Achromobacter sp. YJ-66 were 2% sucrose, 0.067% peptone, 0.1% MgSO4 and 0.1% KH2PO4 in initial pH 7.5 during at 3$0^{\circ}C$ for 72hrs.

• 한국수소및신에너지학회논문집
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• 제22권4호
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• pp.527-533
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• 2011

CNFs had been well addressed due to numerous promising applications in science and technology. Besides the same physicochemical properties of ordinary carbon materials such as active carbons and carbon black, they exhibit specific, e.g., tubular or fibrous structures, a large surface area, high electrical conductivity stability, as well as extremely high mechanical strengh and modulus, which make them a superior material for electrochemical capacitors. In this study, CNFs were pretreated by mechanical milling with different time in mortar and pestle. The milled CNFs were used as active material of electrode whose electrochemical property was tested to find physicochemical characterization variation. CNF electrode milled for 5 min has the highest electric capacitance. XPS spectrum were employed to explore changes in functional group induced from mechanical milling. Crystal size was calculated to analyze change of peak from different milling time by XRD. The CNF milled for 5 min has the largest crystal size and the highest electric capacitance.

• Journal of Electrochemical Science and Technology
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• 제9권4호
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• pp.330-338
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• 2018

The adhesion strength as well as the electrochemical properties of $LiNi_{0.4}Mn_{0.4}Co_{0.2}O_2$ electrodes containing various conductive carbons (CC) such as fiber-like carbon, vapor-grown carbon fiber, carbon nanotubes, particle-like carbon, Super P, and Ketjen black is compared. The morphological properties is investigated using scanning electron microscope to reveal the interaction between the different CC and the active material. The surface and interfacial cutting analysis system is also used to measure the adhesion strength between the aluminum current collector and the composite film, and the adhesion strength between the active material and the CC of the electrodes. The results obtained from the measured adhesion strength points to the fact that the structure and the particle size of CC additives have tremendous influence on the binding property of the composite electrodes, and this in turn affects the electrochemical property of the configured electrodes.

• 한국표면공학회지
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• 제51권5호
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• pp.332-336
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• 2018

Alkaline oxygen electrocatalysis, targeting anion exchange membrane alkaline-based metal-air batteries has become a subject of intensive investigation because of its advantages compared to its acidic counterparts in reaction kinetics and materials stability. However, significant breakthroughs in the design and synthesis of efficient oxygen reduction catalysts from earth-abundant elements instead of precious metals in alkaline media still remain in high demand. One of the most inexpensive alternatives is carbonaceous materials, which have attracted extensive attention either as catalyst supports or as metal-free cathode catalysts for oxygen reduction. Also, carbon composite materials have been recognized as the most promising because of their reasonable balance between catalytic activity, durability, and cost. In particular, heteroatom (e.g., N, B, S or P) doping on carbon materials can tune the electronic and geometric properties of carbon, providing more active sites and enhancing the interaction between carbon structure and active sites. Here, we focused on boron and nitrogen doped nanocarbon composit (BNC nanocarbon) catalysts synthesized by a solution plasma process using the simple precursor of pyridine and boric acid without further annealing process. Additionally, guidance for rational design and synthesis of alkaline ORR catalysts with improved activity is also presented.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.181-184
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• 2001

The biological fixation of carbon dioxide using microalgae have many advantages over chemicals and remove carbon dioxide simultaneously. A ketocarotenoid astaxanthin is hyper-accumulated in the green freshwater microalga, Haematococcus pluvialis. In the present study, the combine effects of carbon dioxide concentration and light intensity on the growth of H. pluvilais were investigated. The carbon dioxide concentration above 10% caused a severe inhibition and around 5% is optimal for growth. Adaptation to high concentration of carbon dioxide enhanced the $CO_2$ tolerance. Specific growth rate calculated differently based upon cell number or dry weight because of the distinctive life cycle patterns of H. pluvialis : small-sized motile green cell and thick cell walled red cyst cell. Based on the light dependence of H. pluvialis, internally illuminated air-lift photobioreactor was designed and operated. Gradual increase of light supply gave more active growth and more effective productivity of astaxanthin than constant light supply.