• 한국환경과학회지
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• 제5권3호
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• pp.369-376
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• 1996

The adsorption of the anionic surfactants, sodium lauryl sulfate (SLS) and sodium dodecylbenzene sulfonate (SDBS) anion surfactants form aqueous solutions with nonionic resins, Amberlite XAD-2, XAD-4 and XAD-7 at temperatures in 15~45$^{\circ}C$ range was studied. Several adsorption isotherm models were used to fit the experimental data, The best results were obtained with the Redlich-Peterson equation and the Freundlich model provided remarkably good fits. For a particular resin at a particular temperature, SDBS was more extensively adsorbed than SLS. The highest adsorption were obtained with XAD-4 resin and the specific surface area of the resins plays a major role in adsorption of the surfactants. Estimations of the isosteric heat of adsorption were indicative of an exothermic process, and their magnitudes manifested a physisorption process.

• Preventive Nutrition and Food Science
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• 제12권2호
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• pp.111-114
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• 2007

Water vapor adsorption kinetics of Inonotus mushroom powders were investigated in temperature and water activity ranges of 20 to 40$^{\circ}C$ and 0.30 to 0.81, respectively. Initial water vapor adsorption rate of mushroom powders increased with increases in temperature and water activity. The temperature dependency of water activity followed the Clausius-Clapeyron equation. The net isosteric heat of sorption increased with an increase in water activity. Water vapor adsorption kinetics of the mushroom powders can be well described by a simple empirical model. Temperature dependency of the reaction rate constant followed the Arrhenius relationship. The activation energy ranged from 56.86 to 91.35 kJ/mol depending on water activity. Kinetic compensation relationship was observed between k$_o$ and E$_a$ with the isokinetic temperature of 790.27 K.

• 한국산업융합학회 논문집
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• 제8권1호
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• pp.37-45
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• 2005

Adsorption equilibrium data of pure solvent vapors (n-Hexane, Toluene, MEK) as well as their binary mixtures on activated carbon (sorbonorit $B_4$) were experimentally determined in the range of 293.2~323.2 K and beyond saturated vapor pressure corresponding to experimental temperature. Langmuir, Freundlich, LRC, W-VSM, FH-VSM were estimated for the predication of single component as well as binary mixtuer systems. The isosteric heat of adsorption at infinite dilution of pure n-hexane, toluene, MEK on activated carbon were 45.18, 25.85, 34.62 Kcal/mol, respectively, also, n-hexane-toluene binary adsorption of activated carbon formed an azeotrope at 293.2 K and total pressure 5.1~10.3 mmHg.

• Korean Chemical Engineering Research
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• 제58권3호
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• pp.458-465
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• 2020

활성탄에 의한 acid fuchsin (AF) 염료의 흡착에 대한 등온선, 동력학 및 열역학적 특성치를 흡착제의 양, pH, 초기 농도, 접촉시간 및 온도를 변수로 하여 수행하였다. 활성탄을 사용한 AF의 흡착에 대한 pH의 영향은 산성(pH 8)에서 흡착백분율이 높은 욕조 현상을 나타냈다. 등온흡착 데이터는 Freundlich, Langmuir, Dubinin-Radushkevich 등온흡착식에 맞춰 보았다. Freundlich 식이 가장 높은 일치도를 나타냈으며, 흡착메카니즘이 다분자층 흡착임을 알았다. 흡착용량은 온도증가와 함께 증가하였다. Freundlich의 분리계수는 이 흡착공정이 적합한 처리공정임을 나타냈다. Dubinin-Radushkevich 등온흡착식에 의해 평가된 흡착 에너지는 활성탄에 의한 AF의 흡착이 물리 흡착임을 확인시켰다. 흡착동력학은 유사이차반응속도식에 잘 맞았다. 입자내 확산 모델에 의해 흡착점에서의 표면 확산이 율속단계로 평가되었다. 흡착공정의 활성화 에너지와 엔탈피 변화는 각각 21.19 kJ/mol, 23.05 kJ/mol 이었다. Gibbs 자유 에너지 변화는 흡착반응이 온도가 높아질수록 자발성이 더 진다는 것을 알려주었다. 양의 엔트로피는 이공정이 비가역적이라는 것을 나타냈다. 등량 흡착열은 본질덕으로 물리흡착임을 나타냈다.

• 한국환경과학회지
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• 제21권6호
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• pp.705-711
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• 2012

Adsorption experiment of carbon dioxide was performed on MCM41 silica with a 30 wt.% EDA(ethylenediamine) loading at different $CO_2$ inlet concentration and various adsorption temperature. The surface characteristics of $CO_2$ capturing agent were carried out using BET analysis, X-ray diffraction and FT-IR. The results of BET showed 781 $m^2/g$ for MCM41 and 464 $m^2/g$ for EDA/MCM41. X-ray diffraction results reveled typical hexagonal pore system. The higher sorption capacity of EDA/MCM41 was about 80 $mg_{CO2}/g_{sorbent}$ with 50% $CO_2$ inlet concentration and 303 K adsorption temperature. The isosteric heat of adsorption in 303-353 K ranged from -25.47 to -28.24 KJ/mole for EDA/MCM41, which indicates $CO_2$-EDA/MCM41 interaction with exothermic adsorption process. Finally, the performance of EDA/MCM41 in 10 consecutive sorption-desorption runs was a stable with only a minor drop in its sorption capacity.

• 공업화학
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• 제18권6호
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• pp.603-606
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• 2007

ECD가 장착된 기체크로마토그래프를 이용하여 다이옥신과 구조적으로 유사한 1,2-디클로로벤젠의 그래파이트 흡착특성을 고찰하였다. 그래파이트에서 1,2-디클로로벤젠의 평형흡착상수는 흡착온도 220, 240, $260^{\circ}C$에서 각각 10.333, 6.167, $4.270m^3/kg$ 값을 나타내었다. 표면 흡착열은 11.554 kcal/mol로 나타났으며 이는 그래파이트의 비표면적이 작고 표면기능기의 양이 적었기 때문이다.

• Korean Chemical Engineering Research
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• 제58권1호
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• pp.127-134
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• 2020

상용흡착제 실로퓨트에 의한 Taxus chinensis 유래 주요 타르 성분인 아세나프텐의 흡착 특성을 조사하였다. 초기 아세나프텐 농도, 흡착 온도 및 시간에 따른 흡착 데이터를 Langmuir, Freundlich, Temkin 및 Dubinin-Radushkevich 등온흡착식에 적용한 결과, Langmuir 등온흡착식이 가장 적합하였다. 동역학적 흡착 데이터는 유사 이차 속도식에 가장 잘 따름을 알 수 있었다. 열역학적 파라미터로부터 흡착 공정이 적합하며 비자발적 발열이었다. 등량흡착열은 흡착량에 의존하지 않아 실로퓨트의 표면에너지가 균일함을 알 수 있었다.

• 한국식품저장유통학회지
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• 제24권4호
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• pp.505-509
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• 2017

Water vapor adsorption kinetics of vacuum-dried jujube powder were investigated in temperature and relative humidity ranges of 10 to $40^{\circ}C$ and 32 to 75%, respectively. Water vapor was initially adsorbed rapidly and then reached equilibrium condition slowly. Reaction rate constant for water vapor adsorption of vacuum-dried jujube powder increased with an increase in temperature. The temperature dependency of water activity followed the Clausius-Clapeyron equation. The net isosteric heat of sorption increased with an increase in water activity. Good straight lines were obtained with plotting of $1/(m-m_0)$ vs. 1/t. It was found that water vapor adsorption kinetics of vacuum-dried jujube powder was accurately described by a simple empirical model, and temperature dependency of the reaction rate constant followed the Arrhenius-type equation. The activation energy ranged from 50.90 to 56.00 kJ/mol depending on relative humidity. Arrhenius kinetic parameters ($E_a$ and $k_0$) for water vapor adsorption by vacuum-dried jujube powder showed an effect between the parameters with the isokinetic temperature of 302.51 K. The information on water vapor adsorption kinetics of vacuum-dried jujube powder can be used to establish the optimum condition for storage and processing of jujube.

• Preventive Nutrition and Food Science
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• 제20권3호
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• pp.215-220
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• 2015

The moisture sorption isotherms of vacuum-dried edible green alga (Capsosiphon fulvescens) powders were determined at 25, 35, and $45^{\circ}C$ and water activity ($a_w$) in the range of 0.11~0.94. An inversion effect of temperature was found at high water activity (>0.75). Various mathematical models were fitted to the experimental data, and Brunauer, Emmett, and Teller model was found to be the most suitable model describing the relationship between equilibrium moisture content and water activity (<0.45). Henderson model could also provide excellent agreement between the experimental and predicted values despite of the intersection point. Net isosteric heat of adsorption decreased from 15.77 to 9.08 kJ/mol with an increase in equilibrium moisture content from 0.055 to $0.090kg\;H_2O/kg$ solids. The isokinetic temperature ($T_{\beta}$) was 434.79 K, at which all the adsorption reactions took place at the same rate. The enthalpy-entropy compensation suggested that the mechanism of the adsorption process was shown to be enthalpy-driven.

• 공업화학
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• 제9권2호
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• pp.286-293
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• 1998

연소배가스로부터 $CO_2$를 선택적으로 분리하기 위한 활성탄 흡착공정 사용시 흡착능 향상을 위하여 $CO_2$와 친화력이 있는 화합물을 함침시키는 방법과 KOH를 함침시킨 후 고온에서 열처리하므로서 활성화시키는 방법이 사용되었다. 알칼리금속, 알칼리토금속, 또는 전이금속의 염화물을 함침시킨 활성탄에 대한 $CO_2$의 흡착량을 측정한 결과 함침 전의 활성탄의 흡착량보다 적었다. 이것은 함침되는 물질이 $CO_2$에 대한 친화력이 없이 단지 활성탄의 미세기공만 막는 결과임을 알 수 있었다. 알칼리금속수산화물 중 KOH를 함침시킨 활성탄에 대한 $CO_2$의 파과실험 결과 유입되는 기체에 수분이 있을 경우 흡착량이 증가했는데 이것은 KOH가 $CO_2$를 흡수하는 성질 때문이었다. 그러나 이 흡착제에 함친된 KOH가 $CO_2$와 반응하여 $K_2CO_3$로 변함에 따라 재현성이 없음을 알 수 있었다. KOH를 함침시킨 후 $800^{\circ}C$에서 열처리하여 활성화시킨 활성탄의 경우 함침된 KOH의 양이 증가할수록 $CO_2$의 흡착량이 증가했으며, KOH와 활성탄의 무게비(KOH/Activated-Carbon)가 4일 때 최대였다. 이 흡착제에 대해 온도별로 측정된 $CO_2$의 흡착량으로부터 Clausius-Clapeyron식을 이용하여 등량흡착열을 구했다. 그리고 고정층 파과실험을 통해 $CO_2$농도와 유속에 따른 파과특성을 살펴보았다.