• 자원리싸이클링
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• 제17권1호
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• pp.59-65
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• 2008

본 연구에서는 폐건전지에 함유되어 있는 이산화망간을 재활용하는 방안을 검토하고자 니켈함유 폐수의 흡착 처리시 흡착제로서 이산화망간을 사용하여 그 특성을 조사하였다. 수중에서 니켈 이온의 거동을 MINTEQ프로그램을 이용하여 조사하고, 흡착질의 초기농도, 반응온도, 그리고 흡착제의 양 및 pH변화에 따른 흡착 특성의 변화양상을 검토하였다. 흡착실험의 결과로부터 흡착질인 $Ni^{2+}$의 초기농도가 증가할수록 흡착량이 감소함을 알 수 있었고, 온도에 따른 $Ni^{2+}$의 흡착특성을 열역학적으로 고찰하였다. 또한 흡착제인 이산화망간의 양이 증가함에 따라 흡착량이 증가하는 것으로 나타났으며, pH가 증가함에 따라 평형흡착량은 증가하는 것으로 조사되었다.

• 대한화학회지
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• 제33권4호
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• pp.350-356
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• 1989

타르, 니코틴 등 몇 가지 연초 에어로솔 성분의 흡착거동을 해석한 결과 비교적 저비점 피흡착질의 흡착률은 축적 동공부피의 증가와 더불어 증가하였다. 반면 비교적 고비점 피흡착질의 흡착률은 보다 작은 반경의 동공부피가 증가할수록 감소하였다. 여기에 사용된 흡착제는 활성탄, 실리카겔, 알루미나 및 활성백토이었다. 비표면적이 큰 흡착제가 보다 큰 흡착률을 가진다는 일반적인 경향은 고비점 피흡착질에 대해서는 성립되지 않았다. 이상의 결과는 위의 흡착거동을 탈착등온식을 기초로 하여 동공부피분포와 관련시켜 검토하므로써 얻어진 것이다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.230-230
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• 2009

In this work, Porous Carbons (PCs) were prepared by using a chemical acid treatment, and the hydrogen storage behaviors of PCs doped by Pt nanoparticles were investigated. The hydrogen storage capacities of the Pt-doped carbons with a platinum content of 0.2 - 1.5 wt.% were evaluated by a volumetric adsorption method at 298K and 10 MPa. The microstructures of samples were examined by XRD and SEM. It was found that the hydrogen storage capacitiesof the PCs dramatically increased, but the amount of hydrogen stored from the samples began to decrease after 0.6 wt.% of Pt content due to the pore blocking. These results indicate that a suitable amount of supported catalysts and layer intervals of carbons had a very important impact on hydrogen storage behaviors.

• 콘크리트학회논문집
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• 제29권4호
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• pp.389-397
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• 2017

시멘트내 $C_3A$상과 $C_4AF$상은 염소이온과 반응하여 프리델염을 생성한다. 프리델염은 구조체에서 염소를 포함하기 때문에 염소이온의 흡착에 매우 중요하다. 외부에서 염소이온이 침투하면, 칼슘 알루미네이트 수화물은 염소이온을 고정하므로, $C_3A$상과 $C_4AF$상 및 AFm상의 염소 흡착 거동을 고찰하는 것은 고정화 현상을 이해하는데 매우 중요하다. 한편, 흡착 등온은 시멘트와 프리델염의 상호관계에서 정량적인 지식을 제공할 뿐만 아니라 그 상호관계의 특성을 이해하는데 매우 중요하다. 본 연구의 목적은 $C_3A$상, $C_4AF$상 및 AFm상의 염소이온 흡착 거동을 고찰하는데 있다. $C_3A$상과 $C_4AF$상의 흡착등온은 이론적 화학당량보다 다소 낮았으며 Langmuir 흡착등온식으로 표현할 수 있었다. AFm상의 흡착등온은 이론적 화학당량보다 매우 낮았으며, Freundlich 흡착등온식으로 표현하였다. 또한 흡착등온 모델에서 온도의 영향 매개변수를 실험범주내에서 온도의 함수로 제안하였다.

• 전기화학회지
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• 제10권3호
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• pp.219-228
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• 2007

The phase-shift method and correlation constants, i.e., the electrochemical impedance spectroscopy (EIS) techniques for studying linear relationships between the behaviors (${\varphi}\;vs.\;E$) of the phase shift ($0^{\circ}{\leq}-{\varphi}{\leq}90^{\circ}$) for the optimum intermediate frequency and those (${\theta}\;vs.\;E$) of the fractional surface coverage ($1{\geq}{\theta}{\geq}0$), have been proposed and verified to determine the Langmuir, Frumkin, and Temkin adsorption isotherms (${\theta}\;vs.\;E$) of H for the cathodic $H_2$ evolution reaction (HER) at noble and transition-metal/aqueous solution interfaces. At the Pt/0.1 MKOH aqueous solution interface, the Langmuir, Frumkin, and Temkin adsorption isotherms (${\theta}\;vs.\;E$), equilibrium constants ($K=5.6{\times}10^{-10}\;mol^{-1}\;at\;0{\leq}{\theta}<0.81$, $K=5.6{\times}10^{-9}{\exp}(-4.6{\theta})\;mol^{-1}\;at\;0.2<{\theta}<0.8$, and $K=5.6{\times}10^{-10}{\exp}(-12{\theta})\;mol^{-1}\;at\;0.919<{\theta}{\leq}1$, interaction parameters (g = 4.6 for the Temkin and g = 12 for the Frumkin adsorption isotherm), rates of change of the standard free energy ($r=11.4\;kJ\;mol^{-1}$ for g=4.6 and $r=29.8\;kJ\;mol^{-1}$ for g=12), and standard free energies (${\Delta}G_{ads}^0=52.8\;kJ\;mol^{-1}\;at\;0{\leq}{\theta}<0.81,\;49.4<{\Delta}G_{\theta}^0<56.2\;kJ\;mol^{-1}\;at\;0.2<{\theta}<0.8$ and $80.1<{\Delta}_{\theta}^0{\leq}82.5\;kJ\;mol^{-1}\;at\;0.919<{\theta}{\leq}1$) of OH for the anodic $O_2$ evolution reaction (OER) are also determined using the phase-shift method and correlation constants. The adsorption of OH transits from the Langmuir to the Frumkin adsorption isotherm (${\theta}\;vs.E$), and vice versa, depending on the electrode potential (E) or the fractional surface coverage (${\theta}$). At the intermediate values of ${\theta}$, i.e., $0.2<{\theta}<0.8$, the Temkin adsorption isotherm (${\theta}\;vs.\;E$) correlating with the Langmuir or the Frumkin adsorption isotherm (${\theta}\;vs.\;E$), and vice versa, is readily determined using the correlation constants. The phase-shift method and correlation constants are accurate and reliable techniques to determine the adsorption isotherms and related electrode kinetic and thermodynamic parameters. They are useful and effective ways to study the adsorptions of intermediates (H, OH) for the sequential reactions (HER, OER) at the interfaces.

• Korean Chemical Engineering Research
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• 제47권5호
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• pp.608-614
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• 2009

본 연구에서는, 비이온성 삼원공중합체 계면활성제인 $EO_{20}PO_{70}EO_{20}$를 주형으로 사용해, 다양한 Si/Ru 몰 비의 루테늄이 치환된 SBA-15들(Ru-SBA-15)을 합성하였다. 촉매 또는 선택적 흡착제 등으로써의 응용가능성을 검토하기 위해 Ru-SBA-15의 질소 또는 산소 흡착/탈착 거동을 조사하였다. Ru-SBA-15의 기공 크기는 Barrett-Joyner-Halenda(BJH) 및 Broekhoff-de Boer/Frenkel-Halsey-Hill isotherm(BdB-FHH) 방법($D_{BdB-FHH}$)을 이용하여 결정하였다. Si/Ru 비율이 50/1인 Ru-SBA 15의 $D_{BJH}$와 $D_{BdB-FHH}$는 각각 3.9, 4.7 nm였다. 투과전자현미경(TEM) 관찰에 의해 Si/Ru의 몰비율이 50인 Ru-SBA 15의 기공 크기는 4.7 nm로 나타났고, 이것은 BdB-FHH 방법을 사용한 $N_2$ 흡착 결과와 일치하였다. 산소 흡착/탈착 등온선으로부터 얻은 Brunauer-Emmett-Teller(BET) 기공 표면적은 질소의 흡착/탈착 등온선으로부터의 기공 표면적보다 높았는데, 각각 $612.7m^2/g$, 그리고 $573.3m^2/g$이었다. X선 회절(XRD) 패턴과 TEM 분석에 의해 본 연구에서 합성한 Ru-SBA-15는 잘 정렬된 육방정계 정렬을 가지는 것을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제46권6호
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• pp.847-856
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• 2014

Spent resin waste containing a high concentration of $^{14}C$ radionuclide cannot be disposed of directly. A fundamental study on selective $^{14}C$ stripping, especially from the IRN-150 mixed bed resin, was carried out. In single ion-exchange equilibrium isotherm experiments, the ion adsorption capacity of the fresh resin for non-radioactive $HCO_3{^-}$ ion, as the chemical form of $^{14}C$, was evaluated as 11mg-C/g-resin. Adsorption affinity of anions to the resin was derived in order of $NO_3{^-}$ > $HCO_3{^-}{\geq}H_2PO_4{^-}$. Thus the competitive adsorption affinity of $NO_3{^-}$ ion in binary systems appeared far higher than that of $HCO_3{^-}$ or $H_2PO_4{^-}$, and the selective desorption of $HCO_3{^-}$ from the resin was very effective. On one hand, the affinity of $Co^{2+}$ and $Cs^+$ for the resin remained relatively higher than that of other cations in the same stripping solution. Desorption of $Cs^+$ was minimized when the summation of the metal ions in the spent resin and the other cations in solution was near saturation and the pH value was maintained above 4.5. Among the various solutions tested, from the view-point of the simple second waste process, $NH_4H_2PO_4$ solution was preferable for the stripping of $^{14}C$ from the spent resin.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권2호
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• pp.128-135
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• 2005

Mixed-mode hydrophobic/ionic matrices exhibit a salt-tolerant property for adsorbing target protein from high-ionic strength feedstock, which allows the application of undiluted feedstock via an expanded bed process. In the present work, a new type of mixed-mode adsorbent designed for expanded bed adsorption, Fastline $PRO^{\circledR}$, was challenged for the capture of nattokinase from the high ionic fermentation broth of Bacillus subtilis. Two important factors, pH and ion concentration, were investigated with regard to the performance of nattokinase ad-sorption. Under initial fermentation broth conditions (pH 6.6 and conductivity of 10 mS/cm) the adsorption capacity of nattokinase with Fastline PRO was high, with a maximum capacity of 5,350 U/mL adsorbent. The elution behaviors were investigated using packed bed adsorption experiments, which demonstrated that the effective desorption of nattokinase could be achieved by effecting a pH of 9.5. The biomass pulse response experiments were carried out in order to evaluate the biomass/adsorbent interactions between Bacillus subtilis cells and Fastline PRO, and to demonstrate a stable expanded bed in the feedstock containing Bacillus subtilis cells. Finally, an EBA process, utilizing mixed-mode Fastline PRO adsorbent, was optimized to capture nattokinase directly from the fermentation broth. The purification factor reached 12.3, thereby demonstrating the advantages of the mixed-mode EBA in enzyme separation.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.765-768
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• 2009

In this work, we prepared the activated multi-walled carbon nanotubes (Acti-MWNTs) with well developed physical surface structures, high specific surface area, and higher adsorption capacity by a physical activation process, in order to enhance the hydrogen storage capacity. The Acti-MWNTs' changes in the crystalline phase and in their lattice distortions were characterized by X-ray diffraction (XRD). The textural properties of the Acti-MWNTs were investigated by a nitrogen adsorption isotherms by Brunauer-Emmett-Teller (BET) equation and Harvath-Kawazoe (H-K) calculation, respectively. The hydrogen storage capacity of the Acti-MWNTs was investigated by BEL-HP at 298 K/100 bar. The hydrogen storage capacity of the Acti-MWNTs was improved with the physical activation, resulted from the formation of new hydrogen-favorable sites on the Acti-MWNT surfaces. In conclusion, the physical activation was one of the effective method to enhance the hydrogen storage capacity of the MWNTs.

• 한국초전도ㆍ저온공학회논문지
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• 제22권2호
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• pp.1-6
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• 2020

Large-scale civil engineering works discharge a large amount of soil suspension contaminated with natural heavy metals. Most of the heavy metal ions due to industrial activities and minings are accumulated in the soils and the sediments of lakes and inner bays through the rivers. It is necessary to remove heavy metals from the soils and the sediments, because some of these heavy metals, such as arsenic and cadmium, have significant biological effects even in small amounts. This study proposes a new volume reduction method of the contaminated soils and sediments by superconducting magnetic separation. Our process can remove the specific minute minerals selectively, which adsorbs heavy metals depending on pH. As a fundamental study, the adsorption behaviors of arsenic and cadmium on minute minerals as a function of pH were investigated, and the adsorption mechanism was discussed based on the crystal structure and pH dependence of surface potential in each minute minerals.