• Analytical Science and Technology
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• v.13 no.2
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• pp.194-199
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• 2000

The study on the adsorption, the surface properties and the antibacterial effects of the Ni-treated PAN based activated carbon fibers was carried out. In the adsorption study on the Ni-treated PAN based ACFs, Type I isotherms for N1-N3 and Type II-Type III isotherms for N4-N6 were obtained, respectively. Futhermore, their adsorbed volumes slowly were decreased with the increase in the mole concentration of Ni on the treated PAN based ACFs. From the BET equation, the specific surface areas of the Ni-treated PAN based ACFs were in the range of $692.58-895.24m^2/g$. The micropore volumes obtained from ${\alpha}_s$-method using common-t value were $0.19-0.56cm^3/g$. The surfaces of PAN based ACFs partially blocked by metal after the treatment were observed from the SEM micrographs. Finally, from the antibacterial effects using Shake flask method against E. coli, the percentage of the effects was 92.5-100% and the antibacterial effect was increased with the increase in mole concentration of Ni treated.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.1
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• pp.1-10
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• 2017

Adsorption is a plausible technology using solid adsorbents for dry capture of carbon dioxide ($CO_2$). In general, narrow size distribution of tiny pores and surface chemical functionalities of solid adsorbents enhance the adsorption capacity of gaseous $CO_2$ molecules. In order to utilize the advantages of fibrous adsorbents, this work prepared activated carbon nanofibers (ACNFs) via the electrospinning process using a polymer precursor of polyacylonitrile (PAN). The spun fibers were 390 nm to 580 nm in thickness with an average surface area of $27.3m^2/g$. The surface structure was improved by a programmed thermal activation at $800^{\circ}C$ in $CO_2$ atmosphere. It was also found that the nitrogen-groups including pyrrole and pyridine were created during the activation facilitaing the selective adsorption as forming enhanced active sites. The finally obtained adsorption capacities were 2.74 mmol/g for pure $CO_2$ flow and 0.74mmol/g for 3000 ppm.

• Analytical Science and Technology
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• v.13 no.5
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• pp.573-583
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• 2000

Activated carbon fibers (ACFs) were prepared from various precursors of plantic, synthetic, and mixed fabrics of viscous rayon and cotton. Their adsorption performances of phenol and methylene blue in aqueous phase were evaluated through their adsorption isotherms, adsorption rates and breakthrough curves. The two adsorbates showed type I adsorption isotherm on ACFs. Adsorption rates to ACFs were 100 fold faster than to GAC. The effective diffusion coefficients of the adsorbates in ACFs were twenty fold greater than in GAC. The ACFs removed completely ten organic pollutants from a prepared water specimens through the 2nd column of a natural filtration method where 50 L of the water samples were treated.

• 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.

• Journal of the Korean Electrochemical Society
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• v.5 no.3
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• pp.117-124
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• 2002

Poly(acrylonitrile)(PAN) solutions in dimethylformamide(DMF) were electrospun to prepare webs consisting of 400nm ultra-fine fibers. The webs were oxidatively stabilized, activated by steam and resulted to be activated carbon fibers(ACFs). The specific surface area was $800\~1230 m^2/g$, which showed a trend of a decrease of the surface area with an increase in activation temperature, showing opposite behavior to the other ACFs. The activation energy of the stabilized fibers for the steam activation was determined as 29.2 kJ/mol to be relatively low indicating the easier activation than that of other carbonized fibers. The ACF webs were characterized by pore size and specific surface uea which would be related to the specific capacitance of the electrical double layer capacitor (EDLC). The specific capacitances measured were 27 F/g, 25 F/g, 22 F/g at the respective activation temperature of $700^{circ}C,\;750^{\circ}C\;800^{\circ}C$, showing similar trend with the specific surface area i.e., the higher activation temperature was, the lower specific capacitance resulted.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.1027-1034
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• 2007

This research was focused on the selective separation of $CO_2$ or $CH_4$ from mixture of these gases, by controlling the size of pore or pore gate. Pitch based activated carbon fibers(ACF) were used as adsorbents. The size of pore gate was controlled by the molecule having similar size to that of pore opening. After the adsorption of adsorbate on pore surface, planar molecules such as benzene and naphthalene covered the pore gate. The slow release of adsorbate from the pores covered by planar molecules makes apertures between planar molecules covering pore gate and this structure can be fixed by rapid pyrolysis. The control of pore gate using benzene as covering molecules could not accomplished due to the simultaneous volatilization of benzene and adsorbate$(CO_2)$ caused by similar temperatures of benzene volatilization and adsorbate desorption. Therefore we replaced benzene with naphthalene looking for the stability at a $CO_2$ desorption temperature. The naphthalene molecule was adsorbed on the ACF up to 15% of ACF weight and showed no desorption until $100^{\circ}C$, indicating that the molecule could be used as a good cover molecule. Naphthalene could cover almost all the pore gate, reducing BET surface area from 753 $m^2/g$ to 0.7 $m^2/g$. A mixed gas$(CO_2:CH_4=50:50)$ was adsorbed on the naphthalene treated OG-7A ACF. The amount of $CO_2$ adsorption increased with total pressure, whileas thai of $CH_4$ was not so much influenced on the pressure, indicating that $CO_2$ made more compounds on the ACF surface along with total pressure increase. The most $CO_2$ and the least $CH_4$ were adsorbed in the condition of 0.4 atm, resulting in the highly pure $CH_4$ left in ACF.

• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.598-603
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• 2015

In this study, electrochemical properties of pitch-based activated carbon fibers (ACFs) were investigated by different heat-treatment temperature of the pitch-based ACFs in order to improve the specific capacitance of electric double-layer capacitor (EDLC). The ACFs were prepared by different heat-treatment temperatures of 1050 and $1450^{\circ}C$, after activation with 4 M KOH at $800^{\circ}C$ using stabilized pitch fiber. The specific surface area of prepared ACFs increased from $828m^2/g$ to $987m^2/g$, also the micropore and mesopore volumes of prepared ACFs were increased. These results because pore was produced by desorbing oxygen and hydrogen elements within the ACFs, and pore size was increased by contraction ACFs by heat-treatment process. Because of the porous properties, the specific capacitance was increased from 73 F/g to 119 F/g using cyclic voltammetry with 1 M $H_2SO_4$ at scan rates of 5 mV/s.