• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.633-638
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• 2019

Indoor air quality underground facilities are not equipped for the removal of volatile organic compounds (VOCs) and they are usually treated by diffusion methods such as ventilation. In this study, an adsorption filter was prepared using various coating methods such as carbon nano fiber (CNF) and dip coating. As a result, the adsorption performance was improved by 2 to 20 times or more compared to that of using the metal foam support. This is maybe due to the enhancement of pore distribution which was confirmed by SEM. In addition, the adsorption performance was 13.95 mg/g by adding lignin, and also an average adsorption performance of 13.25 mg/g was maintained after washing indicating that a highly durable adsorption filter material was prepared. It can be suggested that the developed adsorption filter material can be a potential solution that can fundamentally control VOCs, not via the concentration reduction of mechanical ventilation in underground facilities.

• Journal of Environmental Science International
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• v.31 no.2
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• pp.171-180
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• 2022

Zeolitic material, Z-Y3, was synthesized from coal fly ash (CFA) under low-alkaline conditions (NaOH/CFA ratio = 0.3 and NaOH solution concentrations of 0.0, 0.5, and 1.0 M) using a fusion/hydrothermal method. The adsorption capacities of the fabricated Z-Y3 samples for Cs and Sr ions and the desorption capacity of Na ions were evaluated. The XRD patterns of the Z-Y3 sample fabricated using a 1.0 M NaOH solution (Z-Y3 (1.0 M)) indicated the successful synthesis of a zeolitic material, because the diffraction peaks of Z-Y3 coincided with those of the Na-A zeolite in the 2θ range of 7.18-34.18. Moreover, the SEM images revealed that morphology of the Z-Y3 (1.0 M) sample, which presented zeolitic materials characteristics, consisted of sharp-edged cubes. The adsorption isotherms of Cs and Sr ions on all the fabricated Z-Y3 samples were described using the Langmuir model, and the maximum adsorption capacities of Cs and Sr were calculated to be 0.14-0.94 mmol/g and 0.19-0.78 mmol/g, respectively. The desorption of Na ions from the Cs and Sr ions adsorbed Z-Y3 samples followed the Langmuir desorption model. The maximum desorption capacities of Na ions from the Cs and Sr ions adsorbed Z-Y3 (1.0 M) samples were 1.28 and 1.49 mmol/g, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.251-257
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• 2008

Food compost, having a higher organic contents than soil, could be an alternative material to prevent the proliferation of heavy metals contamination in soil. In this study we used a convection-dispersion local equilibrium sorption model(CDE) and a two-site non-equilibrium sorption model to find the effects on the adsorption and transportation of Pb by mixing food compost with soil and we also tried to find the effect of velocity and concentration of the injected solution on the characteristics of Pb. We measured Pb concentrations in injection-liquid and in effluent, and then applied them to CXTFIT program. As a result of column experiments, some parameters(D, R, ${\beta}$, ${\omega}$) used in two-site non-equilibrium adsorption model were obtained. Characteristics of Pb adsorption and transport were analyzed using the parameters(D, R, ${\beta}$, ${\omega}$) obtained from the CXTFIT program, We could know that mixed soil with food compost showed a higher adsorption capacity from the retardation factor(R) calculated from the breakthrough curve(BTCs) of Pb. Rs of soil and mixed soil are 20.45, 37.45 respectively, indicating that the adsorption and the transportation characteristics could be accessed quantitatively by using of two-site non-equilibrium adsorption model.

• Journal of Environmental Science International
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• v.20 no.2
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• pp.215-222
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• 2011

The adsorption behavior of nitrate nitrogen was investigated from aqueous solution using char prepared from oak chip. The removal rate of nitrate nitrogen was found to be dependent on temperature and it is increased as the temperature increase. Adsorption equilibrium data of nitrate nitrogen on oak char. reasonably fitted Langmuir and Freundlich isotherm models. The adsorption energy obtained from D-R model was 12.5 kJ/mole at $20^{\circ}C$ indicating an ion exchange process as primary adsorption mechanism. Thermodynamic parameters such as ${\Delta}G^o$, ${\Delta}H^o$, and ${\Delta}S^o$ were -23.76 kJ/mole, 26.1 kJ/mole and 89.7 J/K mole at $20^{\circ}C$, respectively, indicated that the nature of nitrate nitrogen adsorption is spontaneous and endothermic.

• Membrane and Water Treatment
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• v.8 no.1
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• pp.73-88
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• 2017

Adsorption kinetics of aqueous ferric ion ($Fe^{3+}$) onto bio-natural rice grains (BRG) have been studied in a batch system. The influence of contact time (0-180 minutes), the dosage of BRG adsorbent (10, 20, 40, and $60gL^{-1}$), and ambient temperature (27, 37, 47, and $57^{\circ}C$) for the adsorption system have been reported. The equilibrium time achieved after 20 minutes of adsorption contact time. The maximum removal of ferric ion is 99% by using $60gL^{-1}$ of BRG, $T=37^{\circ}C$, and $50mgL^{-1}$ ferric ion solution. Adsorption kinetic and diffusion models, such as pseudo-first order, pseudo-second order, and Weber-Morris intra-particle diffusion model, have been used to describe the adsorption rate and mechanism of the ferric ion onto BRG surface. The sorption data results are fitted by Lagergren pseudo-second order model ($R^2=1.0$). The kinetic parameters, rate constant, and sorption capacities have been calculated. The new information in this study suggests that BRG could adsorb ferric ion from water physiosorption during the first 5 minutes. Afterward, the electrostatic interaction between ferric ion and BGR-surface could take place as a very weak chemisorptions process. Thus, there is no significant change could be noticed in the FTIR spectra after adsorption. I recommend producing BGR as a bio-natural filtering material for removing the ferric ion from water.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2358-2366
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• 2013

Iron oxide (ferrihydrite, hematite, and magnetite) coated silica gels were prepared using a low-cost, easily-scalable and straightforward method as the adsorbent material for arsenic removal application. Adsorption of the anionic form of arsenic oxyacids, arsenite ($AsO^{2-}$) and arsenate ($AsO{_4}^{3-}$), onto hematite coated silica gel was fitted against non-linear 3-parameter-model Sips isotherm and 2-parameter-model Langmuir and Freundlich isotherm. Adsorption kinetics of arsenic could be well described by pseudo-second-order kinetic model and value of adsorption energy derived from non-linear Dubinin-Radushkevich isotherm suggests chemical adsorption. Although arsenic adsorption process was not affected by the presence of sulfate, chloride, and nitrate anions, as expected, bicarbonate and silicate gave moderate negative effects while the presence of phosphate anions significantly inhibited adsorption process of both arsenite and arsenate. When the actual efficiency to remove arsenic was tested against 1 L of artificial arsenic-contaminated groundwater (0.6 mg/L) in the presence competing anions, the reasonable amount (20 g) of hematite coated silica gel could reduce arsenic concentration to below the WHO permissible safety limit of drinking water of $10{\mu}g/L$ without adjusting pH and temperature, which would be highly advantageous for practical field application.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.67-71
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• 1997

Activated carbons are the microporous carbonaceous adsorbents which are prepared from carbon-containing source materials such as wood, coal, lignite, peteroleum and sometimes synthetic high polymers. [1-2] Activated carbons shows an ability to adsorbe hydrocarbons of the gas phase. Activated carbons are used in the purification of many kinds of gas phases like hexane, benzene, toluene, gasoline, phenol etc.[3] In this study, cokes from bitminous coal were activated for the purpose of preparing the activated carbons by steam activation. The effect of the activation temperature, time, steam concentration and flow rate on the n-butane adsorption, burn off, surface area and average pore size of the activated carbons, were investigated. The adsorption characteristics of the activated carbons for gasoline are indirectly estimated by n-butane adsorption.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.10a
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• pp.40-44
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• 2000

$Bi_2Sr_2Ca_nCu_{n+1}O_y$($n{\geq}0$; BSCCO)thin film is fabricated via two different processes using an ion beam sputtering method i.e. co-deposition and layer-by-layer deposition. A single phase of Bi2212 can be fabricated via the co-deposition process. While it cannot be obtained by the layer-by-layer process. Ultra-low growth rate in our ion beam sputtering system brings out the difference in Bi element adsorption between the two processes and results in only 30% adsorption against total incident Bi amount by layer-by-layer deposition, in contrast to enough Bi adsorption by co-deposition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.117-121
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• 2002

In this paper, the proper manufacturing method to the use of Illite with many application was studied. We confirmed merit of manufacturing and forming according as respective temperature. The variety of crystallization and surface was confirmed by X-ray diffraction(XRD) analysis and SEM. Then, we performed the experiments such as a antibiosis, a heavy metal adsorption and a gas deodorizaton to confirm the function of Illite. As a result, the adsorption of gas decreased according as the heat treatment of Illite, but the ability of antibiosis wasn't changed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.796-800
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• 2000

Bi$_2$Sr$_2$Ca$_{n}$Cu$_{n+1}$ O$_{y}$(n$\geq$0; BSCCO) thin film is fabricated via two different processes using an ion beam sputtering method i.e. co-deposition and layer-by-layer deposition. A single phase of Bi2212 can be fabricated via the co-deposition process. While it cannot be obtained by the layer-by-layer process. Ultra-low growth rate in our ion beam sputtering system brings out the difference in Bi element adsorption between the two processes and results in only 30% adsorption against total incident Bi amount by layer-by-layer deposition, in contrast to enough Bi adsorption by co-deposition.on.n.