• Biotechnology and Bioprocess Engineering:BBE
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• 제11권6호
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• pp.503-509
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• 2006

Molecularly imprinted polymeric microbeads (MIPMs) were prepared by the suspension and modified suspension polymerization methods using D-phenylalanine as the template, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, toluene as the porogen, polyvinyl alcohol as the stabilizer, and sodium dodecyl sulfate as the surfactant. The addition of a surfactant to the conventional suspension polymerization mixture decreased the mean particle size of the MIPMs and increased the adsorption selectivity. For the modified suspension polymerization method, the mean particle size of the MIPMs was smaller than the particle size of MIPMs prepared via conventional suspension polymerization. Moreover, the adsorption selectivity improved considerably compared to the adsorption selectivities of MIPs reported previously.

• Bulletin of the Korean Chemical Society
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• 제16권2호
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• pp.89-95
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• 1995

The adsorption of methanethiol and benzenethiol on Ag(111) and Ag(100) surfaces is studied respectively, employing ASED (Atom Superposition and Electron Delocalization) method. Metal surfaces are modelled by 3-layer clusters. The corresponding thiolate anions are taken as adsorbates. The highly coordinated binding sites are most favored for both surfaces. The tilted angles of C-S axis from the surface normal are nearly zero. There's Charge transfer from adsorbate to substrate and the stretching frequency of C-S bond upon adsorption is blue-shifted from its gas phase counterpart, and its amount is the smallest at most highly coordinated site. FMO (Fragment Molecular Orbital) analysis of the system give the explanation for these results.

• Bulletin of the Korean Chemical Society
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• 제16권2호
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• pp.143-148
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• 1995

Ketene (CH2CO) adsorption on Ag(111) has been studied in ultrahigh vacuum using electron energy loss spectroscopy and temperature programmed desorption. Ketene adsorbs molecularly on Ag(111) at temperatures below 126 K. The coverage increases linearly with exposure until saturation. No multilayer formation and no shift in desorption temperature with coverage were observed, indicating a lack of attractive interaction between adsorbate molecules. The desorption activation energy is estimated to be 7.8 kcal/mol by assuming first order kinetics and a pre-exponential factor of 1013 sec-1. The adsorption geometry of ketene on the surface is determined from the relative intensities of the vibrational energy loss peaks. The CCO axis of CH2CO is found to be almost parallel to (∼4°away from) the surface and the molecular plane is almost perpendicular to the surface (∼3°tilt).

• Bulletin of the Korean Chemical Society
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• 제20권9호
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• pp.999-1004
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• 1999

Two compact sized globular proteins, β-lactoglobulin and α-lactalbumin were kinetically characterized at the aqueous solution surface with the measurement of surface pressure (π) and surface concentration (Γ) via a radiotracer method. The adsorption kinetics was of diffusion control at early times, the rates of increase of πand Γ being lower at longer times due to growing energy barrier. At low concentrations, an apparent time lag was observed in the evolution of π for β-lactoglobulin but not for α-lactalbumin which was shown to be due to the non-linear nature of the p- G relationship for the former. The area per molecule of an adsorbed β-lactoglobulin during adsorption was smaller than that for spread monolayer since β-lactoglobulin was not fully unfolded during the adsorption. For α-lactalbumin, however, no such difference in the molecular areas for adsorbed and spread monolayer was observed indicating thereby that α-lactalbumin unfolded much more rapidly (has looser tertiary structure) than β-lactoglobulin. Surface excess concentrations of α-lactalbumin was found to evolve in two steps possibly due to the change in the orientation of the adsorbed protein from a side-on to an end-on orientation.

• 한국환경과학회지
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• 제23권5호
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• pp.943-962
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• 2014

Industrial gas drying, dilute gas mixtures purification, air fractionation, hydrogen production from steam reformers and petroleum refinery off-gases, etc are conducted by using adsorptive separation technology. The pressure swing adsorption (PSA) has certain advantages over the other methods, such as absorption and membrane, that are a low energy requirement and cost-effectiveness. A key component of PSA systems is adsorbents that should be highly selective to a gas being separated from its mixture streams and have isotherms suitable for the operation principle. The six standard types of isotherms have been examined in this review, and among them the best behavior in the adsorption of $CO_2$ as a function of pressure was proposed in aspects of maximizing a working capacity upon excursion between adsorption and desorption cycles. Zeolites and molecular sieves are historically typical adsorbents for such PSA applications in gas and related industries, and their physicochemical features, e.g., framework, channel structure, pore size, Si-to-Al ratio (SAR), and specific surface area, are strongly associated with the extent of $CO_2$ adsorption at given conditions and those points have been extensively described with literature data. A great body of data of $CO_2$ adsorption on the nanoporous zeolitic materials have been collected according to pressure ranges adsorbed, and these isotherms have been discussed to get an insight into a better $CO_2$ adsorbent for PSA processes.

• 분석과학
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• 제24권2호
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• pp.94-104
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• 2011

본 연구에서는 양쪽성 메조 다공성 실리카를 다양한 조건(용매, 계면활성제와 올리고머의 량, 용액의 pH)에서 합성하였다. 메조 다공성 실리카를 사용하여 염소 소독으로 인해 음용수 중에 미량 존재하는 변이원성 물질인 MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2-(5H)-furanone)의 흡착에 관한 특성을 연구하였다. 소수성과 친수성의 양쪽성 폴리우레탄 올리고머를 사용하여 합성된 메조다공성 실리카의 경우 뛰어난 흡착특성을 나타내었다. 그리고 보조 계면 활성제의 경우에는 비이온성이며 분자량이 큰 폴리 에틸렌 프로필렌 옥사이드(PEO-PPO)를 사용하여 합성된 메조 다공성 실리키가 가장 좋은 흡착 특성을 보였다.

• 대한화학회지
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• 제9권4호
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• pp.185-189
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• 1965

韓國産 酸性白土類 및 silica gel을 aniline yellow, o-nitro aniline, oil orange 色素 benzene 溶液과 작용시켜 非水溶液에서의 色素吸着率을 측정하였다. 그 吸着率은 silica gel이 酸性白土類보다 컸으며 酸性度에는 무관하였다. 또 上記 色素溶液에 각 10%의 添加溶劑 amine, alcohol, halogen類 化合物등을 加하여 高體酸의 色素吸着率의 변화(吸着阻害率)에 대하여 조사한 결과 위에 적은 順으로 그 영향이 적어지고, 同族體에서는 分子量이 적을 수록 그 영향이 커짐을 알았다. 따라서 非水溶液에서의 吸着은 amine基, 水酸基등과 같은 陰性基를 갖는 化合物은 選擇吸着하고 界面張力에 무관계하여 Traulbe系列의 逆轉現象을 나타내었다. 그 逆轉現象(吸着潮害現象)은 그 順位가 添加溶制의 雙極子能率과 대체적으로 일치하는 것으로 보아 固體酸模體인 活性硅酸과 被吸着體사이의 極盛的化學吸着에 의한 것이라 推定된다. 本實驗結果로부터 固體酸의 非水溶液에서의 吸着메카니즘, Traube 系列의 逆轉現象에 관하여 考察하게 되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2002년도 제22회 학술발표회 초록집
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• pp.57-57
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• 2002

• Advances in nano research
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• 제15권2호
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• pp.105-111
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• 2023

Integrin αvβ3 is one of the receptors expressed in cancer cells. RGD peptides have the potential to target integrin αvβ3 (receptor), which can increase drug delivery efficiency. In this study, 55 different RGD dimer motifs were investigated. At first, the binding energy between RGD peptides and the receptor was calculated using molecular docking. Then, three RGD peptides with the strongest binding energy with the receptor were selected, and their dynamic adsorption on the receptor was simulated by molecular dynamics (MD). The obtained results showed that a sequence that has RGD at the beginning and end with tryptophan (TRP) has strong Lennard-Jones (LJ) and electrostatic interactions with Integrin αvβ3 and has changed the conformation of receptor significantly, which analyzed by root mean square deviation (RMSD) and radius of gyration.

• 한국재료학회지
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• 제26권6호
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• pp.298-305
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• 2016

In this work, recent progress on graphene/metal oxide composites as advanced materials for $HgCl_2$ and $CO_2$ capture was investigated. Density Functional Theory calculations were used to understand the effects of temperature on the adsorption ability of $HgCl_2$ and water vapor on $CO_2$ adsorption on CaO (001) with reinforced carbon-based nanostructures using B3LYP functional. Understanding the mechanism by which mercury and $CO_2$ adsorb on graphene/CaO (g-CaO) is crucial to the design and fabrication of effective capture technologies. The results obtained from the optimized geometries and frequencies of the proposed cluster site structures predicted that with respect to molecular binding the system possesses unusually large $HgCl_2$ ($0.1-0.4HgCl_2g/g$ sorbent) and $CO_2$ ($0.2-0.6CO_2g/g$ sorbent) uptake capacities. The $HgCl_2$ and $CO_2$ were found to be stable on the surface as a result of the topology and a strong interaction with the g-CaO system; these results strongly suggest the potential of CaO-doped carbon materials for $HgCl_2$ and $CO_2$ capture applications, the functional gives reliable answers compared to available experimental data.