• International Journal of Concrete Structures and Materials
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• 제8권4호
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• pp.327-333
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• 2014

The objective of this work was to examine the influence of carbonation on the microstructure of cement materials. Different materials, which were CEM I mortar and paste, CEM II mortar and paste, were carbonated at $20^{\circ}C$, 65 % relative humidity and 20 % of $CO_2$ concentration. The specific surface area and pore size distribution were determined from two methods: nitrogen adsorption and water adsorption. The results showed that: (1) nitrogen adsorption and water adsorption do not cover the same porous domains and thus, we observed conflicts in the results obtained by these two techniques; (2) the CEM II based materials seemed to be more sensible to a creation of mesoporosity after carbonation than the CEM I based materials. The results of this study also helped to explain why observations in the literature diverge greatly on the influence of carbonation on specific surface area.

• 한국안전학회지
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• 제15권4호
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• pp.88-94
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• 2000

The adsorption characteristics of Tharonil on granular activated carbon were experimentally investigated in an adsorber and in a packed column. It was estabilished that the adsorption equilibrium of Tharonil on granular activated carbon was more successfully fitted by Freundlich isotherm equation than Langmuir isotherm equation in the concentration range from 1 to 1000 mg/1. Intraparticle diffusivities (pore and surface diffusivity) of Tharonil were estimated by the concentration-time curve and adsorption isotherm. The estimated values of pore diffusivity and surface diffusivity are $6.70{\times}10^{-6}$ and $2.0{\times}10^{-9}cm^2/s$, respectively. From comparison of intraparticle diffusivities, it was found that surface diffusion was the limiting step for adsorption rate. The break time and breakthrough curve predicted by constant pattern-linear driving force model were shown to agree with the experimental results.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.189.2-189.2
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• 2014

The most stable adsorption structures and energies of four tautomerized forms (keto-1, enol-1, keto-2, and enol-2) of 3-methyl 5-pyrazolone (MP) adsorbed on Ge(100) surfaces have been investigated by Density Functional Theory (DFT) calculation method. Among its four tautomerized forms, we confirmed three tautomerized forms except keto-1 form show the stable adsorption structures when they adsorbed on the Ge(100)-$2{\times}1$ surface as we calculate the respective stable adsorption structures, activation barrier, transition state energy, and reaction pathways. Moreover, among three possible adsorption structures, we acquired that enol-2 form has most stable adsorption structure with O-H dissociated N-H dissociation bonding structure.

• 한국토양비료학회지
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• 제29권3호
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• pp.218-225
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• 1996

수증기 흡착등온식이 5개의 한국토양 표토에서 측정되었다. 이 실험을 통하여 BET와 아라노비치 흡착식의 적용이 가능하였다. BET 등온시은 상대적 수증기압의 범위가 0.03~0.33이었고 아라노비치식에서는 0.03~0.6범위이었다. 계산된 표면적은 BET보다 아라노비치식에서 높았고 흡착에너지는 반대로 나타났다. 토양에서 수증기의 흡착을 해석하는데는 아라노비치 방법이 유용하였다.

• 대한화학회지
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• 제62권2호
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• pp.79-86
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• 2018

This study reported the adsorption of Cu(II) ions onto activated carbon prepared from Myristica Fragrans shell (MFS AC) over independent variables of contact time, activating chemical (NaOH) concentration, initial adsorbate concentration, initial pH of adsorbate solution and adsorption temperature. The MFS AC structure, morphology and total surface area were characterized by FTIR, SEM and BET techniques, respectively. The Cu(II) ions adsorption on the MFS AC (activated using 0.5 M NaOH) fitted best to Freundlich adsorption isotherm (FAI), and the FAI constant obtained was 0.845 L/g at $30^{\circ}C$ and pH 4.5. It followed the pseudo first order of adsorption kinetic (PFOAK) model, and the PFOAK based adsorption capacity was 107.65 mg/g. Thermodynamic study confirmed the Cu(II) ions adsorption should be exothermic and non-spontaneous process, physical adsorption should be taken place. The total surface area and pore volume based on BET analysis was $99.85m^2/g$ and 0.086 cc/g, respectively.

• 방사성폐기물학회지
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• 제7권4호
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• pp.219-227
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• 2009

세 종류의 산화물($TiO_2$(아나타제), $SiO_2$(비결정성) 및 $Al_2O_3$(비결정성)) 표면에 U(VI)이 흡착될 때 유기산이 미치는 영향을 연구하였다. 유기산으로는 살리실산과 피콜린산을 사용하였다. 유기산의 존재 여부에 따라 달라지는 U(VI)의 흡착률 변화를 pH 함수로 측정하였다. 또한 U(VI)의 존재 여부에 따라 달라지는 유기산의 흡착량을 pH 함수로 측정하였다. $TiO_2$의 경우, 살리실산과 피콜린산이 U(VI)과 수용성 착물을 형성함으로써 U(VI)의 흡착률을 저하시킨다. $SiO_2$의 경우, 살리실산은 U(VI) 흡착에 영향을 주지 않지만, 피콜린산은 오히려 U(VI) 흡착을 증가시킨다. 이 현상을 삼성분 표면착물(ternary surface complex) 생성으로 해석하였으며 U(VI) 흡착에 의존하는 피콜린산의 흡착량 변화, 그리고 흡착된 U(VI)의 형광 특성 변화로 이를 확인하였다. $Al_2O_3$의 경우, 살리실산과 피콜린산 모두 U(VI) 흡착과 무관하게 높은 흡착량을 보였으나 U(VI) 흡착을 감소시키지는 않았다. 따라서 삼성분 표면착물 생성을 배제할 수 없으나 이를 확인하기 위해서는 분광 분석과 같은 추가 연구가 필요하다.

• Macromolecular Research
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• 제9권4호
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• pp.197-205
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• 2001

Platelet adhesion onto elastic polymeric biomaterials was tested in vitro by perfusing human whole blood at a shear rate of 100 sec$\^$-1/ for possible verification of mechanisms of initial platelet adhesion perfusion of blood on the polymeric substrates was performed after treatments either with or without pre-adsorption of 1% blood plasma, and either with or without residence of the protein-preadsorbed substrate in phosphate buffered solution. The surfaces employed were elastic polymers such as poly(ether urethane urea), poly(ether urethane), silicone urethane copolymer, silicone rubber and poly(ether urethane) with the anti-calcifying agent hydroxyethane bisphosphate. Each polymer surface treated was exposed in vitro to the dynamic, heparinized whole blood perfused for upto 6 min and the surface area of platelets initially adhered was measured by employing in situ epifluorescence video microscopy. The blood perfusion was performed on the surfaces treated at the following three different conditions: directly on the bare surfaces, after protein pre-adsorption and after residence in buffer for 3 days of the surfaces protein pre-adsorbed for 2 h. The effects of blood plasma pre-adsorption on the initial platelet adhesion was surface-dependent. The amount of the adsorbed fibrinogen and the surface coverage area of the adhered platelets were dependent on the surface conditions whether substrates were bare surfaces or protein pre-adsorbed ones. To test an effect of possible morphological (re)orientations of the adsorbed proteins on the initial platelet adhesion, the polymeric substrate pre-adsorbed with 1% blood plasma was immersed in phosphate buffered solution for 3 days and then exposed to physiological blood perfusion. The surface area of the platelets adhered on these surfaces was significantly different from that of the surfaces treated with protein pre-adsorption only. These results indicated that platelet adhesion was dependent on the surface property itself and pre-treatment conditions such as blood perfusion without any pre-adsorption of proteins, and blood perfusion either after protein pre-adsorption or after subsequent substrate residence in buffer of the substrate pre-adsorbed with proteins. Understanding of these results may guide for better designs of blood-contacting materials based on protein behaviors.

• Environmental Engineering Research
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• 제8권2호
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• pp.91-97
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• 2003

• Korean Chemical Engineering Research
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• 제50권1호
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• pp.83-87
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• 2012

활성탄소섬유를 사용하여 염소소독 후 수돗물 내에 부산물로 존재하는 4종 트리할로메탄을 제거하였다. THMs의 종류별 농도 및 용액의 온도를 달리하면서 흡착실험을 수행하고 활성탄소섬유의 표면특성에 따른 흡착능력과 흡착메카니즘을 살펴본 결과, 4종의 THMs은 모두 Langmuir 타입의 흡착등온곡선을 보이면서 매우 신속하게 활성탄소섬유에 흡착되었다. THMs의 흡착은 활성탄소섬유의 표면에 균일하게 발달된 미세공의 입구에 물리적 및 화학적 수소결합으로 이루어졌다고 판단된다. Langmuir 타입은 특히 저농도 오염원 일때 제거효율이 높기 때문에 수돗물 내에 약 $30{\mu}g/L$ 수준으로 존재하는 THMs의 제거에는 활성탄소섬유가 매우 효과적임을 알 수 있다. 4종 THMs 종류별 흡착량은 큰 차이는 없으나 chloroform, bromodichloromethane, dibromochloromethane, 및 bromoform 의 순서로 증가하였다. 이는 brom 원자수의 증가와 일치하며 극성의 감소로 용해도가 낮아짐에 따라 흡착량이 증가한 것이다.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1321-1326
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• 2011

In this work, the effects of different surface functional groups on the elemental mercury adsorption of porous carbons modified by chemical treatments were investigated. The surface properties of the treated carbons were observed by Boehm's titration and X-ray photoelectron spectroscopy (XPS). It was found that the textural properties, including specific surface area and pore structures, slightly decreased after the treatments, while the oxygen content of the ACs was predominantly enhanced. Elemental mercury adsorption behaviors of the acidtreated ACs were found to be four or three times better than those of non-treated ACs or base-treated ACs, respectively. This result indicates that the different compositions of surface functional groups can lead to the high elemental mercury adsorption capacity of the ACs. In case of the acid-treated ACs, the $R_{C=O}/R_{C-O}$ and $R_{COOH}/R_{C-O}$ showed higher values than those of other samples, indicating that there is a considerable relationship between mercury adsorption and surface functional groups on the ACs.