• Korean Chemical Engineering Research
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• v.43 no.3
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• pp.432-437
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• 2005

An electric swing adsorption (ESA) process for recovering highly pure $CO_2$ from the mixed gases was tested. In this study, activated carbon fibers were used as an adsorbent. The activated carbon fibers showed fast adsorption rate and the high adsorption capacity for $CO_2$ adsorption under the condition of the ambient pressure. Activated carbon fiber with higher specific surface area was suitable to repeated adsorption-desorption cycle process, showing consistent breakthrough curve. Especially, the regeneration method by vacuum combined with ESA improved the performance of desorption process by an additional 17％ regeneration efficiency compared to a vacuum only method, and showed the high regeneration efficiency at comparatively low 7-8 Wh energy.

• Journal of Environmental Science International
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• v.17 no.5
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• pp.565-571
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• 2008

The surface properties of activated carbon modified by acids and base were studied. The influence of the surface chemistry on the adsorption of benzene and acetone vapor on modified activated carbons has been investigated The modified activated carbons were obtained by treatment with acetic acid ($CH_3COOH$), nitric acid ($HNO_3$) and sodium hydroxide (NaOH). The modified activated carbons had similar porosity but different surface chemistry and adsorption characteristics. The total surface acidity (sum of functional groups) of activated carbon (AC-AN) treated by nitric acid was 2.6 times larger than that of activated carbon (AC) before the acid treatment. Especially, carboxyl group was much developed by nitric acid treatment. The benzene equilibrium adsorption capacity of AC-AN decreased 20% more than that of AC. However, the acetone equilibrium adsorption capacity of AC-AN increased 20% more than that of AC because of the large increase of carboxyl group and acidity.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.131-139
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• 2020

The current study focused on the preparation of low-cost PVC-based adsorbing membrane. Metakaolin, as available adsorbent, was embedded into the PVC matrix via solution blending method. The as-prepared PVC/metakaolin mixed matrix membranes were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), pure water permeability and contact angle measurements. The results confirmed the improvement of PWP and hydrophilicity due to the presence of metakaolin in the PVC matrix. Additionally the structure of PVC membrane was changed due to the incorporation of metakaolin in the polymer matrix. The static adsorption capacity of all samples was determined through dye removal. The effect of metakaolin dosage (0-7%) and pH (4, 8, 12) on dye adsorption capacity was investigated. The results depicted that the highest adsorption capacity was achieved at pH of 4 for all samples. Additionally, adsorption data were fitted on Langmuir, Freundlich, and Temkin models to determine the appropriate governing isotherm model. Finally, the dynamic adsorption capacity of the optimum PVC/metakaolin membrane was studied using dead-end filtration cell. The dye removal efficiency was determined for pure PVC and PVC/metakaolin membrane. The results demonstrated that PVC/metakaolin mixed matrix membrane had a high adsorption capacity for dye removal from aqueous solution.

• Journal of the Mineralogical Society of Korea
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• v.9 no.1
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• pp.17-25
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• 1996

Usual experimental adsorption isotherms as a function of relative humidity were constructed from adsorbed water contents in soils, which were kept more than 2 days in vacuum desiccators with constant humidities controlled by sulfuric acids of various concentrations. From the experimental data, the adsorption surface areas were calculated on the basis of the existing adsorption theory, such as Langmuir, BET, and Aranovich. Based on the Gibbs function describing chemical potential of perfect gas, the relative humidities in the desiccators were transformed into their chemical potentials, which were assumed to be the same as the potentials of equilibratedly adsorbed water in soils. Moreover, the water potentials were again transformed into the equivalent capillary pressures, heads of capillary rise, and equivalent radius of capillary pores, on the basis of Laplace equation for surface tension pressure of spherical bubbles in water. Adsorption quantity distributions were calculated on the profile of chemical potentials of the adsorbed water, equivalent adsorption and/or capillary pressures, and equivalent capillary radius. The suggested theories were proved through its application for the prediction of temperature rise of sulfuric acid due to hydration heat. Adsorption heat calculated on the basis of the potential difference was dependant on various factors, such as surface area, equilibrium constants in Langumuir, BET, etc.

• Carbon letters
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• v.3 no.4
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• pp.219-225
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• 2002

The two-step surface modifications of activated carbon was carried out to improve the adsorption capacity of toxic heavy metal ions in liquid phase. Physical and chemical properties of the as-received activated carbon (AC) and two kinds of surface-modified activated carbons ($1^{st}AC$ and $2^{nd}AC$) were evaluated through the BET analysis, surface acidity, and oxides measurements. Specific surface area and pore volume did not significantly change, but surface oxide-group remarkably increased by the surface modification. Equilibrium and batch adsorptions of the various metals, such as Pb, Cd, and Cr, using AC, $1^{st}AC$, and $2^{nd}AC$ were performed at initial pH 5. The adsorption capacity and rate of $2^{nd}AC$ were higher than those of AC and $1^{st}AC$. The carboxylic/sodium carboxylate complex groups were developed from the two-step surface modification of activated carbon, which strongly affected the adsorption of metal ions.

• Clean Technology
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• v.14 no.1
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• pp.47-52
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• 2008

Among various mass transfer models to express adsorption rates for any adsorption processes, the linear driving force (LDF) model is used most. The present investigation aims at finding whether this model may be applied to real adsorption process for separation and removal of benzene. Comparison of numerical simulation results calculated by the LDF model with experimental data allowed us to find the mass transfer coefficients that are most appropriate for a specific adsorption process. Various breakthrough curves were obtained from experiments performed at many different temperatures and pressures, which in turn produced suitable mass transfer coefficients. These dependencies of mass transfer coefficient on temperature and pressure were represented by an Arrhenius type- and a power law type empirical equation, respectively.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.636-645
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• 2022

In this study, we investigated the adsorption characteristics of methyl orange (MO), an anionic dye, on ginkgo shell-based activated carbon (AC). For this purpose, ACs (GS-1, GS-2, and GS-4) with different textural properties were prepared using ginkgo shells and potassium hydroxide (KOH), a representative chemical activating agent. The correlation between the textural characteristics of AC prepared and the mixing ratio of KOH was investigated using nitrogen adsorption/desorption isotherms. The MO adsorption equilibrium experiment on the prepared ACs was conducted under different pH (pH 3~11) and temperature (298~318 K) conditions, and the results were investigated by Langmuir, Freundlich, Sips and temperature-dependent Sips equations. The feasibility of the MO adsorption treatment process of the prepared AC was also investigated using the dimensionless Langmuir separation factor. The heterogeneous adsorption properties of MO for the prepared AC examined using the adsorption energy distribution function (AED) were closely related to the system temperature and textural characteristics of AC. The kinetic results of the batch adsorption performed at different temperatures can be satisfactorily explained by the homogeneous surface diffusion model (HSDM), which takes into account the external mass transfer, intraparticle diffusion, and active site adsorption. The relationship between the activation energy value obtained by the Arrhenius plot and the adsorption energy distribution function value was also investigated. In addition, the adsorption process mechanism of MO on the prepared AC was evaluated using Biot number.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.576-583
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• 2023

This study investigated the possibility of new adsorbent materials made from pig bone-based biomass. To this end, the properties of pig bone-based activated carbon (PAC) prepared from animal biomass were investigated, and its carbon dioxide adsorption performance was examined. KOH was used as the activation agent, and the specific surface area increased with increasing activation temperature, and the adsorption efficiency of carbon dioxide also increased. The sample activated at 800 ℃ exhibited the largest specific surface area of 1208.7 m²/g and the highest CO₂ adsorption efficiency of 3.33 mmol/g at 273 K, 1 bar. However, the specific surface area and the CO₂ adsorption efficiency decreased at activation temperatures above 900 ℃ due to crystallinity changes and overactivation. On the other hand, when the selectivity was calculated using the ideal adsorption solution theory, PAC-900 samples at 273 K and below 0.8 bar showed the best selectivity. These results suggest that the high selectivity of carbon dioxide/nitrogen adsorption at 273 K is due to the carbon dioxide adsorption capacity of hydroxyapatite formed by the decomposition of carbonate when pig bone is activated at 900 ℃ and its crystallinity.

• Journal of Adhesion and Interface
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• v.10 no.3
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• pp.141-147
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• 2009

In this study, the high performance hybrid chemical filter (HPHCF) was prepared by web spray using hot melt adhesive. The material of HPHCF was conditionally made of ion exchange resin and PP non-woven fabric. The optimum temperature and pressure for manufacturing of HPHCF conditions were such as $170^{\circ}C$ and 50 psi, respectively. The characteristics of preparated HPHCF and their adsorption properties of ammonia gas were investigated. The ion exchange capacity (IEC) of HPHCF was increased with increasing the resin contents and their values were higher than pure resin and ion exchange fabrics. The removal efficiency for ammonia gas increased with the increase of packing density of hybrid ion exchange fabrics in the column. It showed 13 min which the adsorption breakthrough time was slower than resin and fibers. The maximum value of adsorption for ammonia gas was 98 percent. And also, the velocity was increased with increasing concentration and flow rate of ammonia gas.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.359-372
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• 2015

Purpose: Through studying the expert's and non-experts panel responses to the questions regarding the attributes of chemical-biological protection cloth quality in terms of the levels of customer demand and technical factors has been studied. We are applied to a QFD matrix with find out the relationship between the selective removal efficiency of chemical-biological cloth and the guidelines of technical approach. Methods: We fabricated several composite of ion-exchange resins with selectively permeable performance designed to facilities water vapor transport and selective adsorption of the harmful gases. With these materials, we characterized on the selectively permeable performance to identify ion-exchange resin with chemical-biological protective cloth. Results: Results showed that ion exchange materials possessed performance with selectively efficiencies as NH3, SOx, NOx and HCl gas. The selective adsorption amount of ammonia and hydrogen gases were $90-80{\mu}g/g$ with TRILITE SCR-BH sulfonated ion exchange resin. The PP non-woven/ion exchange resin adsorbent materials possessed performance with water vapor permeability were 1,100-1,350 g/m2/day, it's was two times high value compare with activated carbon. With these materials, we characterized selectively removal efficiency to identify new ion-exchange material with chemical-biological protective capability. Conclusion: This study shows that a QFD aids in deciding with of the adsorption parameters to optimized with chemical-biological protection cloth manufacturing.