• Archives of Pharmacal Research
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• 제14권3호
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• pp.249-254
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• 1991

Activated carbons from rice-straw can be used as an adsorbents for the purification of water were prepared and evaluated. The adsorptive capacities of activated carbons were measured by iodine, potassium permangante, phenol and metals. It was observed by electron microscope (SEM) and IR spectrum that organic components in the rice-straw and its carbonization product were disappeared. Slit-shaped and porousstructures were formed by activation. There was no relationship between temperature and adsorption of iodine but adsorption of potassium permanganate increased as temperature rose. The adsorption of the phenol was greater than 99%. The adsorption data of phenol at $25^\circ{C}$ obeyed the Freundlich's isotherm. Various metals except sodium were not removed by 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.

• Carbon letters
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• 제2권2호
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• pp.105-108
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• 2001

In this work, the activated carbons (ACs) with high micropores were synthesized from the polystyrene (PS) with KOH as activating agent. And the influence of activation temperature on porosity of the ACs studied was investigated. The porous structures of ACs were characterized by nitrogen adsorption at 77K using BET and D-R equations, and MP and BJH methods. The weight loss behaviors of the samples impregnated with KOH were also monitored using thermogravimetric analyzer (TGA). As a result, it was found that the samples could be successfully converted into ACs with well-developed micropores. From the results of pore size analysis, it was confirmed that elevated activation temperature does lead to the formation and deepening of microstructures without significant change in mesostructures. A thermogravimetric study showed that KOH could suppress the thermal decomposition of the sample, resulting in the increase of carbon yields.

• Carbon letters
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• 제2권2호
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• pp.91-98
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• 2001

Porous carbons have been prepared from different parts of banana stems using two different routes, viz., by pyrolysing the mass at different temperatures as well as by treating the dried mass with chemicals followed by pyrolysis. The pyrolysis behaviour of all these materials has been studied up to $1000^{\circ}C$. Samples treated with acids exhibit more increase in surface area as compared to those treated with alkalies or salts. Analysis of BET surface area shows that the carbon prepared at low temperature shows mixed porosity, i.e., micro and mesopores. Samples heated to high temperature above $700^{\circ}C$ show decrease in macroporosity and increase in microporosity. Liquid adsorption studies have been made using methylene blue and heavy oil. The activated carbons so prepared exhibit higher oil adsorption mainly in the macro and mesopores.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.627-627
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• 2009

In this work, the activated carbons (ACs) with high porosity were synthesized from pitch by KOH chemical activation. The structure and surface properties of ACs were characterized by means of elemental analysis, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy(XPS). And, the influence of the KOH-to-pitch ratio on the porosity of the ACs was investigated using the nitrogen adsorption isotherms at 77 K and a scanning electron microscopy (SEM). As a result, pitch could be successfully converted into ACs with well-developed micro and mesopores. The specific surface areas and pore volumes were increased with an increase of the KOH-to-pitch ratio. Furthermore, it was found that the addition of KOH led to the transformation of the micropores to the meso- and macropores. In the application to electric double layer capacitors (EDLC), the pitch-based ACs showed a higher capacitance per weight and per volume, and an excellent electrochemical stability in the high voltage region.

• Carbon letters
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• 제8권2호
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• pp.134-136
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• 2007

In this work, activated carbons (ACs) were prepared from polystyrene-based cation-exchangeable resin (PSI) by a chemical activation with KOH as an activating agent. The surface morphologies were observed by using SEM, and the textural properties were investigated by using nitrogen adsorption at 77 K. From the experimental results, it was found that the well-developed micro- and mesopores were produced by a chemical activation, and the textural properties including specific surface areas and pore volumes were greatly enhanced. The electrochemical behaviors of the ACs showed similar phenomena with that of textural properties. These results indicated that KOH activation played an important role in the changes of surface, and pore structures, resulting in enhancing the electrochemical properties of the ACs prepared in present work.

• 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.

• 한국지하수토양환경학회지:지하수토양환경
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• 제11권2호
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• pp.1-12
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• 2006

HOCs(hydrophobic organic chemicals)로 오염된 토양을 복원하기 위해 적용한 토양세척 공정에서 발생한 계면활성제 용액을 재사용하는 기술로 활성탄을 사용하였으며 이때 계면활성제와 HOCs 의 분배를 예측 할 수 있는 모델을 개발하였다. 모델은 활성탄이 주입된 계면활성제/HOC 계에서 평형 상태의 농도 분배를 바탕으로 하였다. 본 연구에서 사용한 계면활성제는 Triton X-100, HOC는 phenanthrene, 활성탄은 Darco 20-40, 12-20, 4-12 메쉬 이다. 개발 된 모델을 통해 계면활성제의 농도, HOC의 농도, 활성탄 주입량 그리고 활성탄 입자의 크기에 따른 영향을 살펴보았다. 전산 모사를 통해 각 물질들의 분배결과를 얻었으며 이를 바탕으로 계산된 선택도는 활성탄을 이용한 계면활성제 재사용 기술의 평가에 사용되었다. 본 모델의 전산모사 결과 CMC(s)를 전후하여 서로 다른 분배 양상을 보였으며 모든 경우에서 선택도 값이 1보다 커서 활성탄을 이용한 기술이 적절한 방법임을 알 수 있었다. 모델은 계면활성제를 재사용하기 위한 복잡한 실험 이전 단계에서 간단한 전산 모사를 통해 공정의 성능을 평가할 수 있는 모델로 활용할 수 있을 것이다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제11권2호
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• pp.13-21
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• 2006

다환방향족 탄화수소는 화석연료의 사용 등으로 자연계에 유출되며, 매우 낮은 용해도로 인해 토양과 강한 결합을 형성하여 장기적으로 영향을 준다. 이러한 PAHs로 오염된 토양을 복원하기 위해 계면활성제를 사용한 토양세척 공법을 사용하게 되며, 공정 시 계면활성제의 사용으로 전체 복원 비용이 증가하게 된다. 이에 토양복원 시 사용된 계면활성제의 재사용을 위한 연구들이 많이 진행되고 있다. 본 연구에서는 활성탄을 이용한 계면활성제 재사용 기술을 개발하였다. 활성탄으로는 원료물질과 활성방법이 같고 입자 크기가 다른 세 가지 GAC(Darco 4-12, 12-20, 20-40 메쉬)를 사용하였으며, PAH로는 phenanthrene을 계면활성제로는 Triton X-100을 사용하여 회분식으로 실험을 수행하였다. 이때 Triton X-100 용액에서 phenanthrene의 선택적 흡착정도를 보기위해 선택도를 사용하였다. 실험결과 입자 크기가 작을수록, 비표면적과 기공 부피가 클수록 높은 선택도를 나타내었다. 선택도는 세 활성탄 모두 1보다 높아 Triton X-100 용액으로부터 phenanthrene이 효과적으로 분리됨을 알 수 있었다. 본 연구의 결과, PAHs와 같은 소수성물질로 오염된 토양의 세척시 발생하는 계면활성제 용액을 적절한 특성을 가진 활성탄을 이용하면 오염물질을 선택적으로 제거시킬 수 있음을 알 수 있다. 따라서 활성탄을 이용한 선택적 흡착을 이용하면 토양 세척시 계면활성제 사용량을 줄이게 되어 복원 비용을 절감하는 효과를 가져올 것으로 예상된다.

• Bulletin of the Korean Chemical Society
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• 제21권1호
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• pp.49-55
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• 2000

A series of m-, and p-substituted phenyl 2-thiophenecarboxylates and benzoates was prepared by the reaction of the corresponding acyl chlorides and phenols. Their $^1H$ and $^{13}C$ NMR chemical shifts were analyzed using single substituent parameter (S SP) and dual substituent parameter (DSP) methods. The relative aromaticity index of thiophene was estimated to be 0.92 from the plot of the chemical shift of the carbonyl carbons of the thienoyl esters against chemical shift of the carbonyl carbons of the benzoyl esters.