• Carbon letters
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• 제8권4호
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• pp.299-306
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• 2007

Four stream- activated carbons were prepared by carbonizing apricot stones at $600^{\circ}C$ followed by gasification with steam at $950^{\circ}C$ to burn-off's=17, 32, 49 and 65%. The textural parameters of these activated carbons were determined from nitrogen adsorption results at 77 K. The total pore volume and the mean pore radius increased with the increase of % burn-off whereas the surface area increased with the increase of burn- off from 17 to 32 and further to 49%. Further increase of burn-off to 65% was associated with a considerable decrease in surface area as a result of pronounced pore widening due to pore erosion. The surface pH values of the carbons investigated range between 7.1 and 8.2. The adsorption of oxamyl onto the activated carbon followed pseudo-second order kinetics and the equilibrium adsorption isotherms fitted Langmuir adsorption model. The adsorption of oxamyl proved to be of the physical type and took place in non-micropores. The amount of oxamyl adsorbed expressed as $q_m$ depends to a large extent to the surface area located in non-micropores $S^{\propto}\;_n$, where a straight line relationship passing through the origin was obtained.

• 청정기술
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• 제16권1호
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• pp.33-38
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• 2010

시화/반월 산단 내 활성탄 흡착탑을 사용하는 대표적인 업체에서 수거한 폐활성탄의 탈착특성 및 열량특성을 조사하였다. 열중량분석기를 이용하여 폐활성탄의 탈착반응특성을 조사하였다. 탈착특성 데이터를 바탕으로 탈착반응특성 비교에 중요한 요소인 반응차수 및 활성화에너지를 구하기 위하여 Freeman-Carroll법을 사용하여 반응차수와 활성화에너지 값을 구하였다. 또한 폐활성탄에 흡착되어 있는 휘발성 유기 화합물의 총탄화수소 배출특성을 이용하여 톨루엔을 기준으로 한 휘발성 유기 화합물의 열량을 계산하였다. 본 연구에서 는 반응차수가 0.1~0.8, 활성화에너지가 6.8~26.4 kJ/mol로 나타났으며, 열량은 업체별로 0.4~10.7 kcal/kg으로 나타났다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.304-304
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• 2009

In this study, the adsorption behaviors of mercury ions on the electroless Cu-plated activated carbons have been investigated. The amount of copper on activated carbons have been confirmed by atomic absorption spectrophotometer (AAS). The surface properties of the ACs studied have been characterized by using Boehm's titration method and scanning electron microscopy (SEM).Experimental results showed the adsorption capacity of mercury ions was increased as the electroless Cu plating. This was probably due to the introduction of copper on ACs leaded to an increase in the surface basicity.

• Journal of Electrochemical Science and Technology
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• 제9권2호
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• pp.157-162
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• 2018

In the study, herbaceous biomass waste including giant miscanthus, corn stalk, and wheat stalk were used to prepare commercially valuable activated carbons by KOH activation. The waste biomass predominantly consists of cellulose/hemicellulose and lignin, in which decomposition after carbonization and activation contributed to commercially valuable specific surface areas (>$2000m^2/g$) and specific capacitances (>120 F/g) that exceeded those of commercial activated carbon. The significant electrochemical performance of the herbaceous biomass-derived activated carbons indicated the feasibility of utilizing waste biomass to fabricate energy storage materials. Furthermore, with respect to both economic and environmental perspectives, it is advantageous to obtain activated carbon from herbaceous biomass waste given the ease of handling biomass and the low production cost of activated carbon.

• 상하수도학회지
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• 제20권5호
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• pp.719-726
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• 2006

Adsorption isotherms and kinetics for taste and odor (T&O) compounds and natural organic matters (NOMs) were performed to evaluate the impacts of activated carbon particle size on coagulation and adsorption. Adsorption capacities for iodine, T&O compounds, and NOM of all the activated carbons under #325 mesh were more excellent than those of virgin activated carbons. Small activated carbon particles were more rapidly adsorbed low molecular weight T&O compounds in the water, while those were slowly adsorbed high molecular weight NOM. When the activated carbon and alum were added simultaneously, the adsorption capacity for organics was better than alum was added alone.

• 분석과학
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• 제19권2호
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• pp.121-130
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• 2006

In this study, silver pre-treated activated carbons are transformed using sulfuric acid. From the results of adsorption, each isotherm shows a distinct knee band, which is characteristic of microporous adsorbents with capillary condensation in micropores. In order to reveal the causes of the differences in adsorption capacity and specific surface area after the samples were washed with various strengths of sulfuric acid, surface morphology and external pore structure were investigated by SEM. X-ray diffraction patterns indicated that Ag-activated carbons show better performance for silver and silver compounds removal by post-treatment with acid. The FT-IR spectra of silver-activated carbon samples show that the acid post-treatment was consequently associated with the removal of silver with an increased surface functional group containing oxygen of the activated carbon. The type and quality of oxygen groups are determined on the method proposed by Boehm. For the chemical composition microanalysis of silver-activated carbons transformed by post-treatment with sulfuric acid, samples were analyzed by EDX.

• Carbon letters
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• 제9권1호
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• pp.8-16
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• 2008

Oxidized activated carbons were prepared by reacting steam-activated carbon developed from pecan shells with nitric acid of varying strength (15, 30, 45 and 60%). The textural properties and the chemistry of the surface of the non-oxidized and of the oxidized carbons were determined from nitrogen adsorption and base neutralization capacities. The uptake of Pb(II) and Cd(II) from aqueous solution by these carbons was determined by kinetic and equilibrium experiments as well as by the column method. Treatment with nitric acid brought about drastic decrease in surface area and remarkable increase in the pore size of the carbon with these changes depending on the strength of nitric acid. Nitric acid increased the surface acidity by developing new surface oxygen functional groups of acidic nature. $HNO_3$-oxidized carbons exhibited high adsorption capacities for Pb(II) and Cd(II). The adsorption of these ions increased with the decrease of the surface pH of the carbon and with the increase of the solution pH from 2.5 to 6 and 7. The amount adsorbed from lead and cadmium was also related to the amount of surface acidity, the pH of the point of zero charge and on some metal ion parameters. Cadmium and lead uptake by the investigated carbons followed pseudo-second order model and the equilibrium sorption data fitted Langmuir adsorption model.

• Carbon letters
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• 제9권2호
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• pp.137-144
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• 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.

• 한국환경과학회지
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• 제15권7호
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• pp.695-699
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• 2006

This study is to investigate the relationship between pore structures of activated carbons and adsorption characteristics of toluene vapor using dynamic adsorption method. The surface areas of below $10{\AA}$ in the pore diameter of activated carbons used in this experiment were in the range of 72 -93 % of total cumulative surface area and the toluene vapor equilibrium adsorption capacities were in the range of 350 - 390mg/g. Activated carbons having larger toluene adsorption capacity than the compared activated carbons had relatively pores in the pore diameter range of $7-10{\AA}$. Linear relationship between equilibrium adsorption capacity and cumulative sur- face area was in the diameter range of over $7{\AA}$. It was thought that toluene vapor was relatively well adsorbed on surfaces of pores of over $7{\AA}$.

• Carbon letters
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• 제14권4호
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• pp.234-242
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• 2013

Potassium hydroxide-activated carbons (CK21, CK11, and CK12) were prepared from pistachio nutshells. Physicochemical properties of activated carbons were characterized by TGA, $pH_{pzc}$, Fourier transform infrared spectroscopy, scanning electron microscopy, and $N_2$-adsorption at $-196^{\circ}C$. The examinations showed that activated carbons have high surface area ranging between 695-1218 $m^2/g$, total pore volume ranging between 0.527-0.772 mL/g, and a pore radius around 1.4 nm. The presence of acidic and basic surface C-O groups was confirmed. Batch adsorption experiments were carried out to study the effects of adsorbent dosage, temperature, initial concentration of adsorbate, and contact time on deltamethrin adsorption by activated carbons. The kinetic studies showed that the adsorption data followed a pseudo-second order kinetic model. The Langmuir model showed a maximum adsorption capacity of 162.6 mg/g at $35^{\circ}C$ on CK12. Thermodynamic studies indicated that adsorption was spontaneous and increased with temperature, suggesting an endothermic process.