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

• Journal of the Korean Ceramic Society
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• v.44 no.7
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• pp.358-361
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• 2007

Well-ordered mesoporous SiCBN ceramics have been successfully synthesized by infiltrating a polymeric precursor, which was prepared from borazine and 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane via a hydroboration reaction, into a mesoporous carbon (CMK-3) as a hard template. This was followed by pyrolysis at $1400^{\circ}C$ under nitrogen gas and subsequent oxidative removal of the carbon template without chemical etching. The prepared mesoporous SiCBN ceramic was characterized by a small-angle XRD, TEM, and BET surface area. The resulting mesoporous SiCBN ceramic revealed a BET surface area of $275 m^2g^{-1}$ and a pore volume of $0.8 cm^3 g$ with no crystallization.

• Analytical Science and Technology
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• v.13 no.2
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• pp.131-135
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• 2000

We studied adsorption isotherm, surface properties and antibacterial activity of Cu treated activated carbon fiber (ACF). The BET surface area of Cu treated ACF are distributed to $688.2-887.8m^2/g$. The adsorption results show that BET surface areas move gradually to lower value with increasing treated Cu mole concentration. Using t-method, the specific micropore volumes and average pore size were obtained. From the SEM study, it is also observed that many of micropores in activated carbon fiber are blocked surface after the treatment. And we also observed that the activity of E. coli in kind of colon bacillus increases gradually to larger range with increasing Cu mole ratio. From these results, we suggest the antibacterial mechanism for metal treated ACF.

• Carbon letters
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• v.16 no.2
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• pp.93-100
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• 2015

Surface modified carbon felts were utilized as an electrode for the removal of inorganic ions from seawater. The surfaces of the carbon felts were chemically modified by alkaline and acidic solutions, respectively. The potassium hydroxide (KOH) modified carbon felt exhibited high Brunauer-Emmett-Teller (BET) surface areas and large pore volume, and oxygen-containing functional groups were increased during KOH chemical modification. However, the BET surface area significantly decreased by nitric acid ($HNO_3$) chemical modification due to severe chemical dissolution of the pore structure. The capability of electrosorption by an electrical double-layer and the efficiency of capacitive deionization (CDI) thus showed the greatest enhancement by chemical KOH modification due to the appropriate increase of carboxyl and hydroxyl functional groups and the enlargement of the specific surface area.

• Journal of the Mineralogical Society of Korea
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• v.26 no.2
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• pp.81-86
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• 2013

A series of birnessite was synthesized at 25, 40, 60, and $80^{\circ}C$, respectively. Intensities of XRD and the ratio of signal to noise of the peaks for samples increases with increasing temperature up to $60^{\circ}C$, whereas the intensity and ratio for a sample synthesized at $80^{\circ}C$ decrease, showing that crystallinity of the birnessite synthesized at $60^{\circ}C$ is better than that of the synthesized at $80^{\circ}C$. However, BET surface areas for these two samples show that the surface area increases 39.4 to 89.7 $m^2/g$ with increasing synthesizing temperature from 60 up to $80^{\circ}C$, indicating that a small surface area is shown in a well-crystallized birnessite rather than that of a poorly crystallized birnessite. SEM images show that morphologies for samples are seriously influenced by temperature. The morphology of the synthesized at 25 shows a round-shape, while a plate-like morphology is shown in the synthesized birnessite at $80^{\circ}C$. In addition, a porous layered structure is also shown in the synthesized birnessite at $80^{\circ}C$. These results suggest that physicochemical properties of the synthesized birnessite are sensitively affected by mechanical changes of parameters such as temperature during the synthesization.

• 한국전기화학회:학술대회논문집
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• 2001.06a
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• pp.203-208
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• 2001

• Korean Journal of Materials Research
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• v.9 no.4
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• pp.362-367
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• 1999

We intended to make the activated carbon fibers which could separate, remove and recover the volatile organic compounds of benzene, toluene, acetone and methanol. Changing activation temperature and time, large specific surface area and narrow pore distribution could be obtained. The activated carbon fibers have large adsorption capacity and selectivility for those organic compounds. We characterized the adsorption capability of the activated carbon fibers for benzene, toluene, acetone and methanol by BET specific surface area and pore size and micropore volume measurements. In the result of activation, the maximum value of BET specific surface area of the fibers was $1100\m^2$/g at $800^{\circ}C$ for 60 minutes and $K_2$O was reduced actively in this condition. Their average pore size was 5.8~5.9$\AA$. The activated carbon fibers prepared in this work had high adsorption rate to saturation and the selectibility for the above organic compounds. The adsorbed amount of acetone and methanol(diameter of$ 4.3\AA$ and $4.4\AA$ respectively) which are smaller than micropore diameter in size was 43~49%, which was larger value than benzene and toluene(in the same diameter as $5.9\AA$).

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.382-390
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• 2015

Poly(methyl methacrylate) (PMMA) supports and amine additives were investigated to adsorb $CO_2$. PMMA supports were fabricated by using different ratio of pore forming agents (porogen) to control the BET specific surface area, pore volume and distribution. Toluene and xylene are used for porogens. Supported amine sorbents were prepared by wet impregnation of tetraethylenepentamine (TEPA) on PMMA supports. So we could identify the effect of the pore structure of supports and the quantity of impregnated TEPA on the adsorption capacity. The increased amount of toluene as pore foaming agent resulted in the decreased average pore diameter and the increased BET surface area. Polymer supports with huge different pore distribution could be fabricated by controlling the ratio of porogen. After impregnation, the support with micropore structure is supposed the pore blocking and filling effect so that it has low $CO_2$ capacity and kinetics due to the difficulty of diffusing. Macropore structure indicates fast adsorption capacity and low influence of amine loading. In case of support with mesopore, it has high performance of adsorption capacity and kinetics. So high surface area and meso-/macro- pore structure is suitable for $CO_2$ capture.

• Polymer(Korea)
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• v.26 no.4
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• pp.445-451
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• 2002

In this work, the adsorption characteristics and mechanical interfacial properties of treated silicas by silane coupling agents, such as, ${\gamma}$-methacryloxy propyl trimethoxy silane (MPS), ${\gamma}$-glycidoxy propyl trimethoxy silane (GPS), and ${\gamma}$-mercapto propyl trimethoxy silane (MCPS), were investigated. The equilibrium spreading pressure ($pi_e$), surface free energy ($gamma_s$ s/), and specific surface area ($S_{BET}$) were studied by the BET method with $N_2$/77 K adsorption. The developments of nonpolar functional groups of the silica surfaces treated by silane coupling agents led to the increase in the $S_{BET}$, $pi_e$, and $gamma_s$, resulting in the improved tearing energy ($G_{mc}$)of the silica/rubber composites. The composites treated by MPS showed the superior mechanical interfacial properties in these systems. These results explained by changing of crystalline size, dispersion, agglomerate, and surface functional group of silica/rubber composites.

• Carbon letters
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• v.2 no.3_4
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• pp.176-181
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• 2001

A series of activated carbons were prepared from coconut shells and coal-tar pitch binder by physical activation with steam in this study. The effect of variable processes such as activation temperature, activation time and ratio of mixing was investigated for optimizing those preparation parameters. The activation processes were carried out continuously. The nitrogen adsorption isotherms at 77 K on pellet-shaped activated carbons show the same trend of Type I by IUPAC classification. The average pore sizes were about 19-21${\AA}$. The specific surface areas ($S_{BET}$) of pellet typed ACs increased with increasing the activation temperature and time. Specific surface area of AC treated for 90 min at temperature $900^{\circ}C$ was 1082 $m^2/g$. The methylene blue numbers continuously increased with increasing the activation temperature and time. On the other hand, iodine numbers highly increased till activation time of 60 min, but the rate of increase of iodine numbers decreased after that time. This indicates that new micropores were created and the existing micropores turned into mesopores and macropores because of increased reactivity of carbon surface and $H_2O$.