• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.1059-1064
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• 1998

We have investigated various kind of graphite and MCMB6-28 to develop carbon negative electrode for lithium ion secondary battery. The interlayer length of them was $3.358{\sim}3.363{\AA}$ and the BET specific surface area was $2.95{\sim}26.15m^2/g$. From this study, When the interlayer of them was large and the BET specific surface area was high, the electrochemical characteristics of them was very excellent. Adding 0, 3, 5, wt% of KJ-Black as conducting agent to various graphitic carbon active materials, interface resistance of electrode and electrolyte was less, but rechargeability was better at 3 wt%. At constant current charge and discharge test, discharge capacity was small according to large current.

• Analytical Science and Technology
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• v.13 no.1
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• pp.89-95
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• 2000

Three grades of activated carbon fibers (ACFs) were prepared from various precursors of plantic, synthetic, and mixed fabrics of viscose rayon and cotton. The ACFs an exhibited type I isotherms on the adsorption of nitrogen or argon. Micropore analysis revealed that the ACFs have uniform micropore size distribution in which their peak diameters were in the range of $5.6{\pm}0.3{\AA}$. The BET surface area of ACFs up to $1600m^2g^{-1}$ was proportional to the adsorption capacity of iodine. The BET values of the ACFs prepared were proportional to the burn-off degree of the products.

• YAKHAK HOEJI
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• v.35 no.4
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• pp.277-282
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• 1991

Rheological, colloidal and micromeritical properties were followed to investigate aging mechanisms of hydrous aluminum oxide suspension using Zeta-meter systems, BET adsorption apparatus, Master sizer and electronmicroscope. The results indicate that hydrous aluminum oxide suspension revealed plastic flow with thixotropy. The viscosity, thixotropy and yield value were increased with increasing concentration. During aging process, the viscosity and thixotropic index were increased by an addition of glycerin, however, sorbitol stabilized aging process of the suspension being accompanied with growth of particle size and reduction in specific surface area, pore area and pore volume, and consistency. Diminution of adsorptive power of the particles was also protected by addition of sorbitol to hydrous aluminum oxide suspension. From these results, one of aging mechanism of hydrous aluminum oxide suspension assumed growth and/or crystallization of colloidal particles in aqueous suspension.

• Journal of the Korean Vacuum Society
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• v.2 no.4
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• pp.491-500
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• 1993

The adsorption of nitrogen (77K) and carbon dioxide(273K) was performed on a series of activated carbon fiber. Theadsorption iotherm of nitrogen was typical type 1 and that of carbon dioxide was convex. As the specific surface area increases, there are linear increases in BET constant C mean pore diameter, the width of pore size distribution, wide micropore volume, total micropore volume, total pore volume and external surface area, however, narrow micropore volume was nealy constant . The total micorpore volume fraction in total pore volume is above 97%.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.3
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• pp.207-218
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• 2017

In this study, pitch-based activated carbon fibers (ACFs) were modified with pyrolysis fuel oil (PFO). Carbonized ACF samples were activated at $850^{\circ}C$, $880^{\circ}C$ and $900^{\circ}C$. A scanning electron microscope (SEM) and a BET surface area apparatus were employed to evaluate the indoor radon removal of each sample. Among three samples, the BET surface area and micropore area of ACF880 recorded the highest value with $1,420m^2{\cdot}g^{-1}$ and $1,270m^2{\cdot}g^{-1}$. Moreover, ACF880 had the lowest external surface area and BJH adsorption cumulative surface area of pores with $151m^2{\cdot}g^{-1}$ and $35.5m^2{\cdot}g^{-1}$. This indicates that satisfactory surface area depends on the appropriate temperature. With the above scope, ACF880 also achieved the highest radon absorption rate and speed in comparison to other samples. Therefore, we suggest that the optimum activation temperature for PFO containing ACFs is $880^{\circ}C$ for effective indoor radon adsorption.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.936-941
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• 2010

This study was conducted to investigate formaldehyde removals by silver nano-particles attached on the surface of granular activated carbon (Ag-AC) and to compare the results to those obtained with ordinary activated carbon (AC). The BET analysis showed that the overall surface area and the fraction of micropores (less than $20{\AA}$ diameter) of the Ag-AC were significantly decreased because the silver particles blocked the small pores on the surface of the Ag-AC. The formaldehyde removal capacity of the Ag-AC determined using the Freundlich isotherm was higher than that of AC. Despite the decreased BET surface area and micropore volume, the Ag-AC had the increased removal capacity for formaldehyde, presumably due to catalytic oxidation by silver nano-particles. In contrast, the adsorption intensity of the Ag-AC, estimated by 1/n in the Freundlich isotherm equation, was similar to that of the ordinary AC, indicating that the surface modification using silver nano-particles did not affect the adsorption characteristics of AC. In a column experiment, the Ag-AC also showed a longer breakthrough time than that of the AC. Simulation results using the homogeneous surface diffusion model (HSDM) were well fitted to the breakthrough curve of formaldehyde for the ordinary AC, but the predictions showed substantial deviations from the experimental data for the Ag-AC. The discrepancy was due to the catalytic oxidation of silver nano-particles that was not incorporated in the HSDM. Consequently, a new numerical model that takes the catalytic oxidation into accounts needs to be developed to predict the combined oxidation and adsorption process more accurately.

• Polymer(Korea)
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• v.35 no.1
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• pp.66-71
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• 2011

With the synthesis of hyper crosslinked polymer particle (HCPP), having microporous structure with hydroxyl functional group, synthesized via polymerization reaction consists of three stepssuspension polymerization, hyper crosslinking by Friedel-Craft catalysis and hydrolysis reaction, the effects of the ratio of each monomer, hyper crosslinking conditions and $CO_2$ supercritical drying on the variations of surface morphology, pore size & distribution and BET surface area of HCPP have been investigated. It was observed that the formation of surface crack or fracture of HCPP was intimately related with the degree of hyper crosslinking reaction between microphase separated domains. And the value of BET surface area of HCPP increased with the increase of reaction temperature, time and the amounts of solvent used in hyper crosslinking step. Moreover, $CO_2$ supercritical drying was proven to be a very effective method for removing stabilizer, unreacted monomers and oligomers from HCPP but needed to add methanol as a co-solvent for efficient removing of residual catalyst.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.1
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• pp.23-29
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• 2007

Pitch-coated anatase $TiO_2$ typed was prepared by $CCl_4$ solvent mixing method with different mixing ratios. Since the carbon layers derived from pitch on the $TiO_2$ particles were porous, the pitch-coated $TiO_2$ sample series showed a good adsorptivity and photo decomposition activity. The BET surface area for the carbon layer in the sample increases to increasing with pitch contents. The SEM results present to the characterization of porous texture on the pitch-coated $TiO_2$ sample and pitch distributions on the surfaces for all the materials used. From XRD data a weak and broad carbon peak of graphene with pristine anatase peaks were observed in the X-ray diffraction patterns for the pitch-coated $TiO_2$. The EDX spectra show the presence of C, O and S with strong Ti peaks. Most of these samples are richer in carbon and major Ti metal than any other elements. Finally, the excellent photocatalytic activity of pitch-coated $TiO_2$ with slope relationship between relative concentration of MB ($c/c_o$) and t could be attributed to the homogeneous coated pitch on the external surface by $CCl_4$ solvent method.

• Journal of the Korean Ceramic Society
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• v.45 no.3
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• pp.150-156
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• 2008

Pitch-binded activated carbon fiber(ACF)/$TiO_2$ composite photocatalysts were prepared by Carbon Tetra Chloride (CTC) solvent mixing method with different mixing ratios of anatase to ACF. The result of the textural surface properties demonstrated that there is a slight increase in the Brunauer, Emmett and Teller (BET) surface area of composites with an increase of the amount of ACF. The surfaces structure morphologies of the composites were observed using an Scanning Electron Microscope (SEM). In the XRD patterns for all ACF/$TiO_2$ composites, the diffraction peaks showed the formation of anatase crystallites. The EDX spectra showed the presence of C, O and Si with strong Ti peaks. Most of these samples were richer in carbon and major Ti metal than any other elements. From the photo-decomposition results, the excellent activity of the ACF/$TiO_2$ composites between c/$c_0$ for methylene blue and UV irradiation time could be attributed to both the effects of the photocatalysis of the supported $TiO_2$ and adsorptivity of activated carbon fiber and another carbon derived from pitch.

• Carbon letters
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• v.8 no.1
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• pp.37-42
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• 2007

Carbon nanofiber (CNF) grown catalytically was chemically activated with KOH to attain structural change of CNF. The structural changes of CNF through KOH activation were investigated by using BET and SEM. From the results of BET, it was found that KOH activation was effective to develop particular sizes of pores on the CNF surface, increasing the surface area of CNF. Activated CNF was applied as an anode catalyst support of fuel cell. The effects of different activation conditions including the activation temperature and the activation time on the specific surface area of the CNF activated with KOH were investigated to obtain appropriate structure as a catalyst support. The 60 wt% Pt-Ru catalyst prepared was observed by using TEM and XRD.