• Environmental Engineering Research
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• v.10 no.2
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• pp.45-53
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• 2005

Metal oxide particles with mole ratio of aluminum: titanium of 1:1 were synthesized by a sol-gel method. Langmuir (a) and Freundlich (b) adsorption isotherms of dissolved lead [Pb(Ⅱ)] ion on the metal oxide particles containing aluminum and titanium were determined as follows, respectively,(a) , (b) at pH 6where, correlation coefficients (R2) of Langmuir and Freundlich adsorption isotherms were 0.95 and 0.96, respectively.The overall adsorption rate of Pb(Ⅱ) on the metal oxide particles containing aluminum and titanium was determined by a differential bed reactor. The overall adsorption rate at pH 6 was as a following equation.at pH 6

• Textile Coloration and Finishing
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• v.4 no.4
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• pp.97-103
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• 1992

For manufacturing a high sorptive ACF, we used orthognal array experimental design to get optimum condition. The ability of ACF was measured by $CCl_4$ adsorption and showed those manufacturing conditions were effective in the order of treatment time>oxidative gas>treatment temperature. The optimal condition presented the maximum adsorption rate was at 90$0^{\circ}C$ for 6 minutes with $CO_2$/$H_2O$ gas in the PAN based ACF manufacturing process. The adsorption rate of developed ACF in this experiment was over 100%.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.389-395
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• 2006

The use of pine bark, a natural adsorbent prepared from Korean Red Pine (Pinus densifloral), was studied for its adsorption behavior of lead ion from aqueous solution. Adsorption experiments were carried out on lead ion concentrations of 10mg/L. Adsorption of lead ion could be described by both Langmuir and Freundlich adsorption isotherms. Treatment of the bark with nitric acid greatly increased initial adsorption rate, and equilibrium sorption capacity increased by approximately 48%. A pseudo second-order kinetic model fitted well for the kinetic behavior of lead ion adsorption onto the bark. Acid-treated bark demonstrated its adsorption capacity quite close to that of granular activated carbon. Results of this study indicated that ion exchange and chelation were involved in the adsorption process.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2560-2564
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• 2011

Mesoporous silicon dioxide (meso-$SiO_2$) was prepared using cetyltrimethylammonium bromide as the structure-directing reagent and tetraethyl orthosicate as the silicon source. The influence of pH value on the adsorption behavior of bisphenol A (BPA) was investigated. The adsorption capacity of BPA onto meso-$SiO_2$ increases slightly with pH value from 2 to 6, and then gradually decreases as further improving pH value. The effect of temperature was also studied, and the adsorption capacity of BPA gradually declines with increasing temperature. The adsorption kinetics and thermodynamics of BPA were examined. It is found that the adsorption of BPA onto meso-$SiO_2$ is in good agreement with Langmuir adsorption model. The rate constant of adsorption is $5.17{\times}10^{-3}g\;mg^{-1}\;min^{-1}$, and the maximum adsorption capacity is as high as 353.4 $mg\;g^{-1}$ at 20 $^{\circ}C$.

• Journal of Korean Society on Water Environment
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• v.38 no.2
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• pp.82-94
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• 2022

In this study, chemically modified biochar (NSBP500, KSBP500, OSBP500) derived from starfish was utilized to improve the adsorption ability of the SBP500 (Starfish Biochar Pyrolyzed at 500℃) in a solution contaminated with heavy metals. According to the biochar modification performance evaluation batch tests, the removal rate and adsorption amount of NSBP500 increased 1.4 times for Cu, 1.5 times for Cd, and 1.2 times for Zn as compared to the control sample SBP500. In addition, the removal rate and adsorption amount of KSBP500 increased 2 times for Cu, 1.8 times for Cd, and 1.2 times for Zn. The removal rate and adsorption amount of OSBP500 increased 5.8 times for Cu. The FT-IR analysis confirmed the changes in the generation and movement of new functional groups after adsorption. SEM analysis confirmed Cu in KSBP500 was in the form of Cu(OH)₂ and resembled the structure of nanowires. The Cd in KSBP500 was densely covered in cubic form of Cd(OH)₂. Lead(Pb) was in the form of Pb₃(OH)₂(CO₃)₂ in a hexagonal atomic layer structure in NSBP500. In addition, it was observed that Zn was randomly covered with Zn₅(CO₃)₂(OH)₆ pieces which resembled plates in KSBP500. Therefore, this study confirmed that biochar removal efficiency was improved through a chemical modification treatment. Accordingly, adsorption and precipitation were found to be the complex mechanisms behind the improved removal efficiency in the biochar. This was accomplished by electrostatic interactions between the biochar and heavy metals and ion exchange with Ca²⁺.

• Resources Recycling
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• v.31 no.6
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• pp.25-35
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• 2022

The adsorption/desorption behavior and separation conditions of vanadium and tungsten ions were investigated using a gel-type anion-exchange resin. In the adsorption experiment with the initial acidity of the solution, the adsorption rate of vanadium was remarkably low in strong acids and bases. Additionally, the adsorption rate of tungsten was low in a strong base. An increase in the reaction temperature increased the adsorption reaction rate and maximum adsorption. The effect of tungsten on the maximum adsorption was minimal. The adsorption isotherms of vanadium and tungsten on the ion-exchange resin were suitable for the Langmuir adsorption isotherms of both the ions. For tungsten, the adsorption isotherms of vanadium and tungsten were polyoxometalate. Both ion-exchange resins were simulated using similar quadratic reaction rate models. Vanadium was desorbed in the aqueous solutions of HCl or NaOH, the desorption characteristics of vanadium and tungsten depended on the desorption solution, and tungsten was desorbed in the aqueous solution of NaOH. It was possible to separate the two ions using the desorption process. The desorption reaction reached equilibrium within 30 min, and more than 90% recovery was possible.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.5
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• pp.655-662
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• 2004

An adsorption process to recover the pure $CH_4\;and\;CO_2$ from its mixture was examined. In this study, activated carbon fibers were used as a selective adsorbent. The activated carbon fibers has 78~94% micropore volume and 10.5~20.3${\AA}$ narrow pore size, and showed high adsorption rate and the good selectivity for $CO_2$ under the ambient pressure. The ACF with high surface area showed short mass transfer zone and long breakthrough time and, its adsorption capacity depended on the microporosity. Compared with single component adsorption, the amount adsorbed $CO_2$ on ACF increased by the roll-up of $CH_4$ in mixed gases. The adsorption selectivity increased as now rate and $CO_2$ concentration of mixed gases increased, showing 5.2 selectivity for 75% $CO_2$ concentration.

• 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.

• Membrane and Water Treatment
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• v.9 no.2
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• pp.79-85
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• 2018

In this work, batch adsorption of anionic dye acid green-25 (AG-25) from aqueous solution has been carried out at room temperature using anion exchange membrane (DF-120B) as a noval adsorbent. The effect of various experimental parameters such as contact time, membrane dosage, ionic strength and temperature on the adsorption of dye were investigated. Kinetic models namely pseudo-first-order, pseudo-second-order, Elovich, liquid film diffusion, Bangham and modified freundlich models were employed to evaluate the experimental data. Parameters like adsorption capacities, rate constant and related correlation coefficients for every model are calculated and discussed. It showed that adsorption of AG-25 onto DF-120B followed pseudo-first-order rate expression. Thermodynamic study indicates that adsorption of AG-25 onto DF-120B is an exothermic and spontaneous process.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.189-190
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• 2020

The importance of indoor air quality management has recently been highlighted due to environmental problems such as indoor air pollution. Among indoor air pollutants, carbon dioxide occurs in cooking, heating, burning, and causes forgetfulness, dementia and amnesia. Radon, which occurs in building materials, soil and ground, is a type 1 carcinogen that causes lung cancer in the body through breathing. These substances can be released from the room through ventilation, but there is a limit to reducing the amount of indoor activity due to reduced ventilation conditions due to increased indoor activity time. However, these substances can be removed from the gas by adsorption. The purpose of this study was to identify the properties of granular active and powdered active white soil and mix them to make cement-based active white soil adsorbent matrix for carbon dioxide, fine dust and radon gas adsorption, and to evaluate indoor air improvements according to the mixing scale. The results of the experiment showed that active carbon dioxide adsorption performance increased for carbon dioxide and radon as the exchange rate increased through physical adsorption. In particular, the higher the replacement rate of the granular active bag, the better adsorption performance was shown.