• Journal of the Korean Ceramic Society
• /
• v.36 no.6
• /
• pp.577-582
• /
• 1999

Activated carbon fibers were prepared from stabilized PAN fibers by chemical activation using hydroxide. The variations in specific surface area amount of iodine adsorption micro-structure and pore size distribution in the activated carbon fibers after the activation process were discussed. In the chemical activation using potassium hydroxide specific surface area of about 2545m2/g and amount of iodine adsorption of 2049 mg/g were obtained at the condition of KOH/fiber ratio of 1 and 800$^{\circ}C$ Nitrogen adsorption isotherms for PAN based activated carbon fibers showed the type I in the Brunauer-Deming-Deming-Teller classification indicating the micro-pores consisting the activated fibers.

• Carbon letters
• /
• v.9 no.2
• /
• pp.137-144
• /
• 2008

The commercial activated carbons are typically prepared by activation from coconut shell char or coal char containing lots of inorganic impurities. They also have pore structure and pore size distribution depending on nanostructure of precursor materials. In this study, two types of commercial activated carbons were applied for EDLC electrode by removing impurities with acid treatments, and controlling pore size distribution and contents of functional group with heat treatment. The effect of the surface functional groups on electrochemical performance of the activated carbon electrodes was investigated. The initial gravimetric and volumetric capacitance of coconut based activated carbon electrode which was acid treated by $HNO_3$ and then heat treated at $800^{\circ}C$ were 90 F/g and 42 F/cc respectively showing 94% of charge-discharge efficiency. Such a good electrochemical performance can be possibly applied to the medium capacitance of EDLC.

• Carbon letters
• /
• v.2 no.1
• /
• pp.9-14
• /
• 2001

Adsorption and desorption characteristics of methyl iodide at high temperature conditions up to $250^{\circ}C$ by TEDA-impregnated activated carbon, which is used for radioiodine retention in nuclear facility, was experimentally evaluated. In the range of temperature from $30^{\circ}C$ to $250^{\circ}C$, the adsorption capacity of base activated carbon decreased sharply with increasing temperature but that of TEDA-impregnated activated carbon showed higher value even at high temperature ranges. Especially, the desorption amount of methyl iodide on TEDA-impregnated carbon represented lower value than that on unimpregnated carbon. The breakthrough curves of methyl iodide in the fixed bed packed with base carbon and TEDA-impregnated activated carbon at high temperature were compared. TEDA-impregnated activated carbon would be applicable to adsorption process up to $150^{\circ}C$ for the removal of radioiodine in a nuclear facility.

• Journal of Korean Society on Water Environment
• /
• v.25 no.4
• /
• pp.568-572
• /
• 2009

The adsorption characteristics of tartrazine by granular activated carbon were experimentaly investigated in the batch adsorber and the packed column. The adsorptivity of activated carbon for tartrazine was largely improved by pH control, and 98 percent of initial concentration could be removed at pH 3. It was estabilished that the adsorption equilibrium of tartrazine on granular activated carbon was sucessfully fitted by Freundlich isotherm equation in the concentration range from 50 mg/L to 1,000 mg/L. The characteristics of breakthrough curve of activated carbon packed column, which depend on the design variables such as initial concentration, bed height, and flow rate, were studied.

• Carbon letters
• /
• v.11 no.1
• /
• pp.13-21
• /
• 2010

Coconut shell activated carbon (CSAC) was investigated for its ability in the removal of two neutral chlorinated organic compounds, namely trichloroethylene (TCE) and dichloromethane (DCM) from aqueous solution using a packed bed column. The efficiency of the prepared activated carbon was also compared with a commercial activated carbon (CAC). The important design parameters such as flow rate and bed height were studied. In all the cases the lowest flow rate (5 mL/min) and the highest bed height (25 cm) resulted in maximum uptake and per cent removal. The experimental data were analysed using bed depth service time model (BDST) and Thomas model. The regeneration experiments including about five adsorption-desorption cycles were conducted. The suitable elutant selected from batch regeneration experiments (25% isopropyl alcohol) was used to desorb the loaded activated carbon in each cycle.

• Carbon letters
• /
• v.16 no.1
• /
• pp.19-24
• /
• 2015

The breakthrough behaviour of activated charcoal cloth samples against an oxygen analogue (OA) of sulphur mustard has been studied using the modified Wheeler equation. Activated charcoal cloth samples having different surface area values in the range of 481 to $1290m^2/g$ were used for this purpose. Breakthrough behaviour was found to depend on the properties of the activated charcoal cloth, properties of the OA and the adsorption conditions. Activated charcoal cloth with a high surface area of $1290m^2/g$, relatively large surface density of $160g/m^2$ and coarser fiber structure exhibited better kinetic saturation capacity value, 0.19 g/g, against OA vapours when compared to others, thus confirming its potential use in foldable masks for protection against chemical warfare agents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.4
• /
• pp.415-421
• /
• 2004

The voltage profile of Zinc/Air battery during discharge has very flat pattern in a given voltage range, But, if not enough the porosity in cathode, as a result of that capacity, energy and discharge voltage of batteries become low. Therefore, we focused the pore effects in activated carbon for cathode. We examined discharge voltage, specific capacity, specific energy, resistance and characteristics during the GSM pulse discharge upon different kinds of activated carbon in Zinc/Air battery, Also we measured porosity of the air cathode according to the ASTM. So we achieved improvement of specific capacity, specific energy and discharge voltage according to increase meso pores of activated carbon. We found the optimized activated carbon material for Zinc/Air battery.

• Journal of Environmental Health Sciences
• /
• v.19 no.4
• /
• pp.25-32
• /
• 1993

Granular activated carbon is commonly used in fixed-bed adsorbers to remove organic chemicals. In this experiment organic chemical solutions were prepared by adding the reagent grade organic chemical to distilled water. Isotherm adsorption tests of volatile organic chemicals were conducted using bottle-point technique and column test. Organic chemicals after passing through the column were extracted with hexane and analyzed with gas chromatography (Hewlett-Packard 5890) to check the adsorption capacity and breakthrough curve. The result were as follows: 1. The BET surface area of coconut activated carbon was 658~1,010 m$^2$/g where as coconut shell carbon was 6.6 m$^2$/g. Coconut activated carbon increased the BET surface area and adsorption capacity in bottle-point isotherm. 2. The adsorption capacity of coconut activated carbon for trichloroethylene (TCE) was reduced in the presence of humic substance. 3. A decrease in particle size of activated carbon resulted in higher adsorption capacity and lower intraparticle diffusion coefficient. It is reflected not only as a decrease in Freudlich adsorption capacity value (K) but also as an increase in Freudlich exponenent value (1/n).

• Proceedings of the KIEE Conference
• /
• 2005.07c
• /
• pp.2010-2012
• /
• 2005

Activated carbon was activated with chemical treatment to attain high surface area with porous structure. We have been considered activated carbon is the ideal material for high voltage electric double layer capacitor due to their high specific surface area, good conductivity and chemical stability. In this study we found that increase in electrochemical capacitance due to activated carbon. Also chemically activated carbon and water treatment have resulted larger capacitance and also exhibits better electrochemical behavior, and is about 15% more than in untreated state. The structural change in activated carbon through chemical treatment activation was investigated by using SEM and XRD. In this study, the dependence of the activation behavior with KOH in the micro structure of host materials will be discussed. Furthermore, the relation to the electric double layer capacitance, especially the specific capacitance per unit area, is also discussed.

• Journal of the Korean Society of Safety
• /
• v.24 no.4
• /
• pp.34-39
• /
• 2009

The adsorption characteristics of amatanth by granular activated carbon were experimently investigated in the batch adsorber and the packed column. The adsorptivity of activated carbon for amaranth were largely improved by pH control, and 94 percent of initial concentration(100mg/L) could be removed at pH 9. It was estabilished that the adsorption equilibrium of amaranth on granular activated carbon was sucessfully fitted by Freundlich isotherm equation in the concentration range from 1mg/L to 100mg/L. The characteristics of breakthrough curve of activated carbon packed column, which depend on the design variables such as initial concentration, bed height, and flow rate, were studied.