• 한국미생물·생명공학회지
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• 제41권1호
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• pp.60-69
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• 2013

Purified melanin pigment from Klebsiella sp. GSK was characterized by thermogravimetric, differential thermal, X-ray diffraction and elemental analysis. This melanin pigment is structurally amorphous in nature. It is thermally stable up to $300^{\circ}C$ and emits a strong exothermic peak at $700^{\circ}C$. Its carbon, hydrogen and nitrogen composition is 47.9%, 6.9% and 12.0%, respectively. It was used to scavenge metal ions and free radicals. After immobilizing the pigment and using it to adsorb copper and lead ions, the metal ion adsorption capacity was evaluated by atomic absorption spectroscopy (AAS) and the identity of melanin functional groups involved in the binding of metal ions was determined by Fourier transform infrared (FT-IR) spectroscopy. Batch adsorption studies showed that 169 mg/g of copper and 280 mg/g of lead were adsorbed onto melanin-alginate beads. The metal ion adsorption capacity of the melanin-alginate beads was relatively significant compared to alginate beads. The metal ion desorption capacity of HCl was greater (81.5% and 99% for copper and lead, respectively) than that of EDTA (80% and 71% for copper and lead, respectively). The ability of the melanin pigment to scavenge free radicals was evaluated by inhibition of the oxidation of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and was shown to be about 74% and 98%, respectively, compared with standard antioxidants.

• 공업화학
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• 제5권2호
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• pp.189-198
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• 1994

초고진공하에서 열탈착 실험에 의하여 오산화바나듐 촉매상에서 일산화탄소와 메탄올의 홉착특성을 연구하였다. 일산화탄소는 오산화바나듐 촉매표면의 격자산소 결함을 갖는 바나듐이온이나 바나듐이온에 결합된 이중결합성 산소에 흡착하였다. 격자산소 결함을 갖는 바나듐이온에 흡착한 일산화탄소는 380K에서 탈착되었으며, 바나듐이온에 결합된 이중결합성 산소에 흡착한 일산화탄소는 격자산소와 결합하여 탄산기의 형태를 형성한 후 이산화탄소로 탈착되면서 촉매 표면을 환원시켰다. 선흡착되거나 후흡착되는 산소에 의하여, 탄산기의 형태로 흡착하는 일산화탄소의 흡착량은 증가하였다. 오산화바나듐 촉매상에서 메탄올을 흡착시킨 후 메탄올, 포름알데히드, 일산화탄소, 수소 등의 열탈착실험에 의하여 메탄올의 흡착특성을 연구하였다. 메탄올은 298 K에서 오산화바나듐 촉매상에 methoxy와 hydroxyl기를 형성하면서 분해흡착하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.80-80
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• 2010

Graphene has attracted tremendous attention for the last a few years due to it fascinating electrical, mechanical, and chemical properties. Up to now, several methods have been developed exclusively to prepare graphene, which include micromechanical cleavage, polycrystalline Ni employing chemical vapor deposition technique, solvent thermal reaction, thermal desorption of Si from SiC substrates, chemical routes via graphite intercalation compounds or graphite oxide. In particular, polycrystalline Ni foil and conventional chemical vapor deposition system have been widely used for synthesis of large-area graphene. [1-3] In this study, synthesis of mono-layer graphene on a Ni foil, the mixing ratio of hydrocarbon ($CH_4$) gas to hydrogen gas, microwave power, and growth time were systemically optimized. It is possible to synthesize a graphene at relatively lower temperature ($500^{\circ}C$) than those (${\sim}1000^{\circ}C$) of previous results. Also, we could control the number of graphene according to the growth conditions. The structural features such as surface morphology, crystallinity and number of layer were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM), transmission electron microscopy (TEM) and resonant Raman spectroscopy with 514 nm excitation wavelength. We believe that our approach for the synthesis of mono-layer graphene may be potentially useful for the development of many electronic devices.

• 공업화학
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• 제27권2호
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• pp.165-170
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• 2016

본 연구에서는, 실제 $150000Nm^3/hr$ 규모의 연소로에서 운전된 $VO_x/TiO_2$ SCR 촉매의 활성저하 원인을 규명하고자 XRD, BET, AES ICP, $H_2$-TPR, $NH_3$-TPD 분석을 수행하였다. $TiO_2$의 상전이 및 $VO_x$의 결정화가 발생하지 않았기 때문에 열에 의한 촉매의 활성저하는 없는 것으로 나타났다. 반면, 성분 분석결과 S의 함량이 검출되지 않고 Ca이 다량 검출됨에 따라 $SO_2$에 의한 피독이 아닌 Ca에 의한 피독이 발생하였음을 확인하였으며 이러한 Ca의 피독은 $NH_3$의 흡착량을 감소시켜 반응활성을 감소시키는 것으로 나타났다.

• 농업과학연구
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• 제46권1호
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• pp.33-44
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• 2019

This study was conducted to examine the components of phytoncide from a pine forest in the southern temperate zone. Recent studies have found that a large amount of phytoncide is released not only from cypress trees but also from pine trees. Because the amount released is the highest during summer, we selected a warm climate region in the southern temperate zone and measured the concentration in the month of August. To capture the phytoncide from the forest atmosphere, we used the adsorption tube method with a mini pump and successfully gathered 9 L of forest air at a flow rate of 150 mL/min. We performed duplicate sampling from two different tubes installed at the same location and derived the mean value. A gas chromatography/mass spectrometer detector with thermal desorption spectroscopy was utilized to perform quantitative and qualitative analyses of the captured material. The results showed that the average phytoncide particle of the pine forest in the southern temperate zone contained a number of components as follows in descending order: ${\alpha}$-Pinene (39%, $0.28ng/m^3$), followed by ${\beta}$-Pinene (16%, $0.11ng/m^3$), D-Limonene (8%, $0.06ng/m^3$), camphor (6%, $0.04ng/m^3$), camphene (6%, $0.04ng/m^3$), and p-Cymene (5%, $0.04ng/m^3$). There were also 13 additional phytoncide components in trace amounts. The results of this study are expected to provide a useful dataset for building a "Healing-forest".

• 공업화학
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• 제4권4호
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• pp.721-730
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• 1993

$Cu_xH_3-2_xPMo_{12}O_{40}{\cdot}_nH_2O$에서 구리의 치환양 x를 변화시켜 여러 가지의 헤테로폴리산 동염 촉매를 제조하고, 열분석, X-선 회절분석, 적외선 분광분석, 비표면적 측정, 전자현미경 분석, 암모니아의 승온탈착법 등으로 촉매의 특성을 조사하였다. 아크롤레인의 산화반응에 대한 이 촉매계의 반응특성은 고정층 연속반응기에서 조사하였다. 이 촉매들은 $200^{\circ}C$ 근처에서 결정수의 탈리가 일어났고 구리의 치환에 따른 구조수의 탈리는 $300{\sim}400^{\circ}C$ 사이에서 관찰되었다. 이들 촉매는 Keggin 구조를 가짐을 확인할 수 있었고, 구리의 치환양이 증가함에 따라 Keggin 음이온인 $(PMo_{12}O_{40})^{3-}$의 분해 정도가 증가하였으며, 이때 분해 생성물로 소량의 $MoO_3$와 $P_2O_5$가 관찰되었다. x가 증가할수록 아크롤레인의 전화율이 감소하였는데 이것은 비표면적과 전체 산점의 양이 감소하였기 때문인 것으로 판단된다. 그러나 단위면적당 반응속도와 아크릴산의 선택도는 x=1.0에서 가장 높게 나타났으며 이 촉매는 독특한 산점분포를 나타내었다.