• 한국환경과학회지
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• 제11권4호
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• pp.339-346
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• 2002

Physico-chemical properties of the activated sludges(Suyoung and Changlim treatment plant), such as SVI(sludge volume index), absorbance, specific surface area, and specific resistance using Buchener funnel test were investigated with changing anaerobic storage time. This experimental condition was found that it was possible to estimate a linear relationship between their parameters such as specific surface area specific resistance, and sludge volume index(SVI). The specific surface area and the specific resistance to filtration of the activated sludges of Suyoung and Changlim treatment plant were found as 123.6~136.6$m^2$/gDS and 41.5~44.9$m^2$/gDS(dry solid), and 1.09$\times$10$^{14}$ ~5.48$\times$10$_{14}$ m/kg and 1.05$\times$10$^{14}$ ~2.48$\times$10$^{14}$ m/kg, respectively. The results gave a good linear relationship between the specific surface area and the specific resistance, r=2.25$\times$10$^{12}$ s-8.10$\times$10$^{13}$ ($R^2$=0.8885) at Suyoung treatment plant and r=1.26$\times$10$^{13}$ s-4.75$\times$10$^{14}$ ($R^2$=0.8756) at Changlim treatment plant.

• Journal of Microbiology and Biotechnology
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• 제12권6호
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• pp.878-881
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• 2002

The goal of the current research was to assess the influence of the growth rate of Nocardia amarae on its overall metal binding capacity. Batch sorption isotherms for cadmium (Cd), copper (Cu), and nickel (Ni) showed that Nocardia cells harvested from chemostat cultures at a dilution rate of $0.33d^-1$ had a significantly higher metal sorption capacity than cells grown at 0.5 and $1d^-1$. The cell surface area estimated using a dye technique indicated that pure N. amarae cells grown at a lower growth rate had a significantly more specific surface area than cells harvested from a higher growth rate operation. Accordingly, this difference in the specific surface area seemed to indicate that the higher metal sorption capacity of the slowly growing Nocardia cells was due to their higher specific surface area.

• 펄프종이기술
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• 제45권1호
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• pp.35-41
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• 2013

In this study, we investigated the effect of the number of passes through agrinder on the pore characteristics of nanofibrillated cellulose (NFC) mat. The beaten pulp suspension was used to make NFC suspension using a grinder. To evaluate the pore characteristics of a NFC mat, the surface morphology of the dried NFC mat was observed with FE-SEM and the specific surface area was analyzed with BET nitrogen gas adsorption. The structure of NFC mat was changed with the different number of passes and drying methods. The specific surface area of NFC mat increased with the increase in the number of passes. The 20-passed NFC mat had 20 times larger specific surface area ($141m^2/g$) compared to the 0-passed NFC mat. The specific surface area was strongly correlated with the average pore size in NFC mat. The average pore diameter in NFC mat was calculated from the gas sorption isotherms using BJH model. The value was 13 - 15 nm, indicating that the NFC mat had mesoporous structure.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.64.2-64.2
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• 2010

In order to improve the overall power conversion efficiency in dye-sensitized solar cells (DSSCs), it is very important to secure the sufficient surface area of photocatalytic nanoparticles layer for absorbing dye molecules. It is because increasing the amount of dye absorbed generally results in increasing the amount of light harvesting. In this work, we proposed a new method for increasing the specific surface area of photocatalytic titanium oxide ($TiO_2$) nanoparticles by using an inorganic templating method. Salt-$TiO_2$ composite nanoparticles were synthesized in this approach by spray pyrolyzing both the titanium butoxide and sodium chloride solution. After aqueous removal of salt from salt-$TiO_2$ composite nanoparticles, mesoporous $TiO_2$ nanoparticles with pore size of 2~50 nm were formed and then the specific surface area of resulting porous $TiO_2$ nanoparticle was measured by Brunauer-Emmett-Teller (BET) method. Generally, commercially available P-25 with the average primary size of ~25 nm $TiO_2$ nanoparticles was used as an active layer for dye-sensitized solarcells, and the specific surface area of P-25 was found to be ~50 $m^2/g$. On the other hand, the specific surface area of mesoporous $TiO_2$ nanoparticles prepared in this approach was found to be ~286 $m^2/g$, which is 5 times higher than that of P-25. The increased specific surface area of $TiO_2$ nanoparticles will absorb relatively more dye molecules, which can increase the short curcuit current (Jsc) in DSSCs. The influence of nanoporous structures of $TiO_2$ on the performance of DSSCs will be discussed in terms of the amount of dye molecules absorbed, the fill factor, the short circuit current, and the power conversion efficiency.

• Korean Chemical Engineering Research
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• 제57권1호
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• pp.133-141
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• 2019

침전법으로 환류방법 또는 수열합성법을 이용하여 산 염기점을 갖는 고비표면적 지르코니아를 합성하였다. 제조된 지르코니아는 침전제로 수산화암모늄 수용액을 사용하여 Zr 용액의 pH를 2에서 10 범위 내에서 조절하였으며 질소흡착분석, X-선 회절분석(XRD), 이소프로판올 승온탈착법(IPA-TPD), 주사전자현미경 분석, X-선 광전자분광분석, 산-염기점 분석을 통해 IPA 분해반응의 촉매활성과 연관하여 특성분석을 수행하였다. 환류방법을 사용할 시, tetragonal 상이 높은 지르코니아를 얻기 위해서는 Zr 용액의 pH가 높아야 하며, pH 9 이상에서는 순수한 tetragonal 상의 지르코니아 합성이 가능하였다. 또한, 비표면적이 큰 지르코니아를 얻기 위해서는 높은 pH가 요구되었으며, pH 10에서 합성한 경우에는 $600^{\circ}C$에서 소성 후에도 $260m^2g^{-1}$의 높은 비표면적이 얻어졌다. 하지만 같은 조건 하에서 고압이 수반되는 수열합성에는 $40m^2g^{-1}$ 이하의 매우 낮은 비표면적을 보였으며, monoclinic 상의 지르코니아가 합성되었다. 고 비표면적 tetragonal 상의 지르코니아를 얻기 위해서는 용액의 pH가 가장 큰 영향을 미쳤으며, 용액의 pH와 무관하게 높은 압력이 필요한 수열합성에서는 monoclinic 지르코니아가 생성되었으며 상대적으로 비표면적이 낮게 나타났다. 높은 비표면적과 tetragonal 상을 갖는 지르코니아는 염기점에 비해 산점이 우세하여 IPA 분해반응에서 선택적 탈수반응만 진행되는 프로필렌만 생성되었다.

• The Korean Journal of Ceramics
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• 제4권3호
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• pp.245-248
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• 1998

Porous carbon fiber composites (CFCs) having variable specific surface area ranging 35~1150 $\m^2$/g were reacted to produce silicon carbide fiber composites with SiO vapor generated from a mixture of Si and $SiO_2$ at 1673 K for 2 h under vacuum. Part of SiO vapor generated during conversion process condensed on to the converted fiber surface as amorphous silica. Chemical analysis of the converted CFCs resulting from reaction showed that the products contained 27~90% silicon carbide, 7~18% amorphous silica and 3~63% unreacted carbon, and the composition depended on the specific carbide, 7~18% amorphous silica and 3~63% unreacted carbon, and the composition depended on the specific surface area of CFCs. CFC of higher specific surface area yielded higher degree of conversion of carbon to silicon and conversion products of lower mechanical strength due to occurrence of cracks in the converted caron fiber. As the conversion of carbon to silicon carbide proceeded, pore size of converted CFCs increased as a result of growth of silicon carbide crystallites, which is also linked to the crack formation in the converted fiber.

• 한국세라믹학회지
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• 제28권1호
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• pp.29-36
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• 1991

Microporous glasses in the system TiO2-SiO2-Al2O3-B2O3-CaO-Na2O were prepared by the phase-separation technique. Morphology and distribution of pore and specific surface area of glasses heated and leached out at various conditions were investigated by SEM and Porosimeter. Crystallization of glasses heated above transition temperature was also inspected by X-ray diffraction method. When the heating temperature and time increased, the pore size and volume increased, but the specific surface area decreased above the critical temperature. The phase-separation, specific surface area and pore size showed more sensitive change on the variation of heating temperature than of heating time. The specific surface area and micropore volume of porous glasses prepared in this study were about 120-330$m^2$/g and 0.001-0.01cc/g, respectively. Mean pore size of porous glasses were about 20-90$\AA$. Anatase phases was deposited when the parent glass was heat-treated at 75$0^{\circ}C$ for 6hrs.

• Bulletin of the Korean Chemical Society
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• 제16권6호
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• pp.498-503
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• 1995

The adsorption behaviors of two major components purified, endo Ⅱ and exo Ⅱ, from Trichoderma viride were investigated using microcrystalline cellulose with different specific surface area as substrates. Adsorption was found to apparently obey the Langmuir isotherm and the thermodynamic parameters, ΔH, ΔS, and ΔG, were calculated from adsorption equilibrium constant,K. The adsorption process was found to be endothermic and an adsorption entropy-controlled reaction. The amount of adsorption of cellulase components increased with specific surface area and decreased with temperature and varied with a change in composition of the cellulase components. The maximum synergistic degradation occurred at the specific weight ratio of the cellulase components at which the maximum affinity of cellulase components obtains. The adsorption entropy and enthalpy for respective enzyme system increased with specific surface area increase. The adsorption entropy was shown to have a larger value with enzyme mixture.

• 한국응용과학기술학회지
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• 제28권2호
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• pp.225-231
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• 2011

The electrochemical characteristics of electric double layer capacitor(EDLC) were investigated using various carbon materials. The physical properties such as specific surface area and mean pore size of activated carbon were analyzed by BET. The results of the activated carbon used for electrode material showed that the specific surface areas varied from 600 to 1500 $m^2$/g and mean pore sizes from 1.74 to 2.88 nm. A maximum specific capacitance of 0.30 F/$cm^2$ was obtained for the activated carbon with the highest specific surface area and ionic conductivity. Also, it was found that the electrochemical results of the cyclic charge-discharge tests were stable.

• Applied Biological Chemistry
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• 제31권1호
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• pp.86-91
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• 1988

경북(慶北) 월성산(月城産) Zeolite광석으로 조제(調製)한 $1{\sim}0.5,\;0,5{\sim}0.25,\;0.25{\sim}0.1$ 및 <0. 1mm의 4종류의 Zeolite 획분(劃分)의 비표면적(比表面積)이 수증기(水蒸氣) 및 EGME흡착법(吸着法)에 의(依)해 측정(測定)되었다. 수증기(水蒸氣) 및 EGME에 의(依)한 Zeolite의 비표면적(比表面積)은 각각 평균(平均) 106 및 $161m^2/g$으로 측정물질(測定物質)에 따라 약간의 차이(差異)가 있었으나 두방법(方法) 공히 입경(粒徑)의 대소(大小)에 따른 비표면적(比表面積)의 차이(差異)는 거의 없었다. $H_2O$ 분자경(分子徑)과 Mordenite공경(孔徑)을 근거(根據)하여 비교검토(比較檢討)한 결과측정(結果測定)된 비표면적(比表面積)은 실제표면적(實際表面積)의 일부분(一部分)으로 추정(推定)되었다. 따라서 Zeolite의 표면적(表面積)을 정확(正確)히 측정(測定)하기 위해서는 새로운 측정법(測定法)의 개발(開發) 필요성(必要性)이 인정(認定)된다.