• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.11
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• pp.977-984
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• 2013

A hygroscopic rotor comprises many microchannels with high adsorption characteristics. In this study, the iterative adsorption/desorption processes that were affected by the humid air flow in a channel were numerically simulated. In consideration of the accuracy and computational costs, in the desiccant layer, only surface diffusion was considered in this simulation. The results were compared with the previous numerical results and found to show good agreement. By conjugating the heat and mass transfer between the desiccant and the flow layers, temporal and spatial changes in the vapor mass fraction, adsorbed liquid water mass fraction, and temperature in the channel were presented.

• Preventive Nutrition and Food Science
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• v.12 no.2
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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.

• Journal of the Korean Society of Industry Convergence
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• v.8 no.1
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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.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.77-80
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• 2007

To increase the capacity of hydrogen adsorption, transition metals were adopted as catalyst. The PAN-based CNFs involving transition metal were obtained by electrospinning method and heat treatment. To study the surface of carbon fibers, SEM analysis was conducted. The mass of transition metals were spreaded or covered among CNFs. XRD and EDX analysis were used to confirm transition metals on the surface of carbon fibers. Volumetric method was used for studying the capacity of hydrogen adsorption on the carbon fibers involving transition metals. In this study. vanadium has the best characteristics among chromium, titanium, and copper for hydrogen adsorption.

• Membrane and Water Treatment
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• v.15 no.3
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• pp.107-115
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• 2024

This study proposes the recycling of MVS as a value-added product for the removal of phosphate from aqueous solutions. By comparing the phosphate adsorption capacity of each calcined adsorbent at each temperature of MVS, it was determined that the optimal heat treatment temperature of MVS to improve the phosphate adsorption capacity was 800 ℃. MVS-800 suggests an adsorption mechanism through calcium phosphate precipitation. Subsequent kinetic studies with MVS-800 showed that the PFO model was more appropriate than the PSO model. In the equilibrium adsorption experiment, through the analysis of Langmuir and Freundlich models, Langmuir can provide a more appropriate explanation for the phosphate adsorption of MVS-800. This means that the adsorption of phosphate by MVS-800 is uniform over all surfaces and the adsorption consists of a single layer. Thermodynamic analysis of thermally activated MVS-800 shows that phosphate adsorption is an endothermic and involuntary reaction. MVS-800 has the highest phosphate adsorption capacity under low pH conditions. The presence of anions in phosphate adsorption reduces the phosphate adsorption capacity of MVS-800 in the order of CO 3 2-, SO 4 2-, NO 3- and Cl-. Based on experimental data to date, MVS-800 is an environmentally friendly adsorbent for recycling waste resources and is considered to be an adsorbent with high adsorption capacity for removing phosphates from aqueous solutions. This paper combines the advantages of gray predictor and AI fuzzy. The gray predictor can be used to predict whether the bear point exceeds the allowable deviation range, and then perform appropriate control corrections to accelerate the bear point to return to the boundary layer and achieve.

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.61-72
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• 1997

This research aims to remove the heavy metals, nonbiodegradable COD(NBDCOD), and color using the coal waste. The experimental by heat treatment was performed to advance the adsorption capacity. The results are as follows ; i) The coal waste had the adsorption capacity of heavy metals and the rates were in the range of 20 to 30 percents. ii) The heat treatment was the optimum condition that the reaction time was 6 hours at $500^{\circ}C$, , iii) In the column experimen, non-treated coal waste removed the COD and color in the range of 20 to 60 percents. iv) Heat-treated coal waste showed higher removal rate of the color in biological effluent, and heavy metal and COD removal rates were changed by the filteration rates.

• Food Science and Preservation
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• v.24 no.4
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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.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.2
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• pp.150-159
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• 1996

In this study, to obtain the basic data for the optimum moisture control system, moisture adsorption characteristics, adsorption isotherms models for water and surface physical characteristics of burley and flue-cured tobacco were investigated. By the hypothesis' the phenomenon of moisture adsorption of tobacco is the same as the first order reaction, the wetting constant (k) and equilibrium moisture content were obtained. And activation energy, frequency factors were also calculated by applying its data to Arrhenius equation. The Kamei's empirical formula of moisture adsorption isotherms showed the best agreement with the experimental data and its correlation coefficient (r) was 0.997. It can be seen that specific surface area of burley is 157 m2/g, that of flue-cured is 152 m2/g, -△H1 of adsorbed monolayer is 45,972 J/mol, 45,486 J/mol, respectively, and the condensation heat (40,595 J/mol) being caught in adsorbed multilayer is less than that of monolayer.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.3
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• pp.286-297
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• 2010

This study deals with the effect of pretreatment on the $CO_2$ adsorption capacity of zeolitic adsorbents including a commercial A-type zeolite and cation exchanged adsorbents. The pre-heating could change the intrinsic properties such as specific surface area and adsorption capacity of the adsorbent. As a result of the experiment, the moisture previously filled inside might affect the potential adsorption capacity of the adsorbent, and could be disappeared throughout the heat treatment. An optimum pretreatment temperature for the test adsorbent was found to be $400^{\circ}C$, at which temperature enabled more than 90% refreshment. Precise examination through the TPD test showed that the TSA (Temperature Swing Adsorption) process would be desirable in dry adsorption of $CO_2$.

• Clean Technology
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• v.9 no.4
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• pp.153-161
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• 2003

This study was carried out as a basic experiment for development of adsorption process in which benzene and toluene was adsorbed on activated carbon. In the static adsorption experiment, Adsorption character of benzene and toluene was studied by change of temperature and pressure. Activated carbon 12~20mesh and activated carbon 20~40mesh was used as adsorbents, Benzene, toluene and nitrogen as adsorbates. Experimental data were obtained to fitted to Langmuir isotherm and dependence was acquired. Parameters of adsorption heat and adsorption constant was obtained. Static adsorption experiment for binary mixtures confirmed that Langmuir isotherm parameters could be applicable to Extended Langmuir isotherm. Experimental technique used in this study only requires pressure measurement and this technique is different from the conventional method which measures gas mole compositions before adsorption and after adsorption. The dynamic adsorption experiment was carried out and the experimental results was compared with the computer simulation results. In this study, basic data was acquired to decide adsorption conditions in the process.