• Journal of Energy Engineering
• /
• v.13 no.2
• /
• pp.166-172
• /
• 2004

The activated carbon was produced from Sancheong bamboo by steam and carbon dioxide gas activation methods. The carbonization of raw material was conducted at 90$0^{\circ}C$ and gas activation reactions were conducted with respect to various conditions. -activation temperature 750-90$0^{\circ}C$, the flow rate of steam 0.5-2g-$H_2O$/g-char$.$hr, the flow rate of carbon dioxide 5-30$m\ell$-$CO_2$/g-char-min and activation time 1-5 hr. The prepared activated carbons were measured yield, the adsorption capacity of iodine and methylene blue, BET specific surface area and pore size distribution. The adsorption capacity of iodine (680.5-1526.1 mg/g) and methylene blue (18.3-221.5 mg/g) increased with creasing activation temperature and activation time. The adsorption capacity of iodine and methylene blue increased with the activation gas quantity in the range of 0.5-1.5g-$H_2O$/g-charㆍhr, 5-18.9$m\ell$-Co$_2$/g-charㆍmin. But those decreased over those range due to the pore shrinkage. The steam activation method was superior in efficiency to carbon dioxide activation method.

• Journal of the Korean Ceramic Society
• /
• v.36 no.10
• /
• pp.1016-1021
• /
• 1999

In this study activated carbon fibers were prepared from PAN-based carbon fibers by physical activation with steam or carbon dioxide. The variations in specific surface area amount of iodine adsorption and pore size distribution of the activated carbon fibers after the activation process were discussed. in steam activation BET surface area of about 1019 m2/g was obtained after 77% burn-off while carbn dioxide activation produced ACF with 694m2/g of BET surface area after 52% burn-off. However carbon dioxide activation produced at a similar degree of activation higher micropore volume(0.37 cc/g) and amount of iodine adsorption (1589mg/g) than steam activation. Nitrogen adsorption isotherms for (PAN based activated carbon fibers that prepared by physical activation were of type I in the Brunauer-Deming-Deming-Teller classification

• Carbon letters
• /
• v.1 no.2
• /
• pp.69-75
• /
• 2000

Naphtha cracking bottom oil was reformed with heat treatment and then spun at $310^{\circ}C$. These pitch-based carbon fibers were carbonized at $1000^{\circ}C$ after oxidation at $280^{\circ}C$, for 90 min. These fibers were chemically activated with molar ratio of KOH/CF (1 : 1) at different temperatures ($250{\sim}900^{\circ}C$) for 1 hr. The process of activation was characterized with DTA, TGA, BET surface area and pore size distribution. The activation of fibers by KOH was performed by several process. One is the reduction process that carbon fiber was reacted with $K_2O$ produced from dehydration process above $400^{\circ}C$. The other is the process that $K_2CO_3$ was directly reacted with carbon fiber. At $800^{\circ}C$, the activation was performed by catalyzed mechanism that $K_2O$ was obtained from the reaction of metal potassium with $CO_2$, then was changed to $K_2CO_3$. At $870^{\circ}C$, the activation was also observed that activation mechanism was promoted by metal catalyst with $CO_2$ from decomposition of $K_2CO_3$. The specific surface area of prepared activated carbon fibers was dependent on the activation mechanism. The specific surface area was in the range of $1519{\sim}2000\;cm^3/g$ and was the largest prepared at $870^{\circ}C$. The pores developed were mostly micropores which was very narrow and uniform. The total pore volume was $0.58{\sim}0.77\;cm^3/g$.

• Carbon letters
• /
• v.9 no.2
• /
• pp.127-130
• /
• 2008

This study aims to find a correlation between XRD and Raman result of the activated carbon fibers as a function of its activation degrees. La of the isotropic carbon fiber prepared by oxidation in carbon dioxide gas have been observed using laser Raman spectroscopy. The basic structural parameters of the fibers were evaluated by XRD as well, and compared with Raman result. The La of the carbon fibers were measured to be 25.5 ${\AA}$ from Raman analysis and 23.6 ${\AA}$ from XRD analysis. La of the ACFs were 23.6 ${\AA}$ and 20.4 ${\AA}$, respectively, representing less ordered through activation process. It seems that the $I_D/I_G$ of Raman spectra were related to crystallite size(La). Raman spectroscopy has demonstrated its unique ability to detect structural changes during the activation of the fibers. There was good correlation between the La value obtained from Raman and XRD.

• Carbon letters
• /
• v.15 no.4
• /
• pp.295-298
• /
• 2014

In this work, nanoporous carbons (NPCs) were prepared by the self-assembly of polymeric carbon precursors and block copolymer template in the presence of tetraethyl orthosilicate and colloidal silica. The NPCs' pore structures and total pore volumes were analyzed by reference to $N_2$/77 K adsorption isotherms. The porosity and elemental mercury adsorption of NPCs were increased by activation with carbon dioxide. It could be resulted that elemental mercury adsorption ability of NPCs depended on their specific surface area and micropore fraction.

• Journal of Environmental Science International
• /
• v.10 no.5
• /
• pp.373-380
• /
• 2001

In recent years, the demand of activated carbon has been increasing steadily because of the environmental problems. Among them waste and water treatment and removal of poisonous gas were invorved. Therefore, in this study, activated carbon was made from the waste chinese cabbage and measured the iodine adsorption ability, carbonization yield, and activation yield of the produced activated carbon. The result showed that the carbonization yield was decreased when carbonization temperature was increaed and that the optimal carbonization temperature was $600{\circ}C$. The optimal concentration of NaOH for removing ash in the raw sample was 1~2N. The range of iodine adsorption number of activated carbon using chinese cabbage at $600{\circ}C$. carbonization was 610.82mg/g to 1019.58mg/g. The activation result of carbonization sample showed that the optimal activation condition was the carbonization at $400\circ}C$ and the activation at$700{\circ}C$. So the production of activated carbon using chinese cabbage was possible in the aspect of reuse of resource and decrease of environmental pollution compared to the commercial activated carbon.

• Journal of Korea Foresty Energy
• /
• v.21 no.2
• /
• pp.17-24
• /
• 2002

Activated carbons were prepared from pine bark by steam activation, and pore structures and specific surface areas were then investigated. Three different types of kilns were used for the activation. When the stationary-vertical-or stationary-horizontal-type kiln was used for the steam activation to prepare an activated carbon from the bark, it was not possible to produce activated carbon having high specific surface areas exceeding 1,000 $m^2／g$. Using bark powder improved the specific surface area, but it was still not high enough. When the rotary-horizontal-type kiln was used for the activation, the activated carbons prepared had high specific surface areas of more than 1,000$m^2／g$, which was similar to a commercial first-grade activated carbon. The activated carbon prepared by the rotary kiln had a wide distribution of pore size ranging from microporous to mesoporous.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.223-226
• /
• 2005

For $CO_2-free$ hydrogen production and better utilization of the produced carbon, catalytic decomposition of methane over rubber-grade carbon blacks manufactured from coal tar was carried out. The catalytic activities of several domestic carbon blacks were compared. A pelletized carbon black exhibited considerably lower activity and activation energy than the fluffy( loose) carbon black of the same grade. This difference is considered due to the binder that was added during pelletization. For pelletized carbon blacks, a tendency was observed that the activity per unit mass of catalyst increased with the specific surface area of the carbon black. Another tendency was also observed that the activation energy increased with the primary particle size or decrease of the specific surface area.

• Carbon letters
• /
• v.9 no.3
• /
• pp.203-209
• /
• 2008

The objective of this work is to study the feasibility of the preparation of the activated carbon (AC) from coconut tree flowers using high temperature fluidized bed reactor (HTFBR). The activating agent used in this work is steam. The reactor was operated at various activation temperature (650, 700, 750, 800 and $850^{\circ}C$) and activation time (30, 60, 120 and 240 min) for the production of AC from coconut tree flowers. Effect of activation time and activation temperature on the quality of the AC preparation was observed. Prepared AC was characterized in-terms of iodine number, methylene blue number, methyl violet number, ethylene glycol mono ethyl ether (EGME) surface area and SEM photographs. The best quality of AC from coconut tree flowers (CFC) was obtained at an activation temperature and time of $850^{\circ}C$ and 1 hr restectively. The effectiveness of carbon prepared from coconut tree flowers in adsorbing crystal violet from aqueous solution has been studied as a function of agitation time, carbon dosage, and pH. The adsorption of crystal violet onto AC followed second order kinetic model. Adsorption data were modeled using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity $q_m$ was 277.78 mg/g., equilibrium time was found to be 180 min. This adsorbent from coconut tree flowers was found to be effective for the removal of CV dye.

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