• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.43.2-43.2
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• 2010

Most of previous methods for the dispersions of carbon nanotube were achieved by various chemical functionalizations. In this study, however, we generated highly water dispersed carbon nanofibers by altering intrinsic materials property only, such as crystallinity of outer layers of carbons, without chemical treatment. Although most of chemical functionalization requires acidic treatment and may degrade their chemical functions by interacting with other molecules, suggested strategy demonstrated a simple but chemically non-degradable carbon nanotube for the application of various medical applications, such as drug delivery system and implant coatings.Furthermore, protein adsorption was increased by the reducing surface crystalinity since outer activated surface induced more adsorption of oxygen and eventually greater protein adsorption than pristine carbon nanofibers.

• Analytical Science and Technology
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• v.17 no.1
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• pp.82-84
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• 2004

The quantitative trace analysis of ions could be deteriorated by filter papers because of the effect of adsorption. Generally the adsorption of anions on filter paper did not occurred. Instead, $Cl^-$ and $NO{_3}^-$ ions were extracted from the filter papers. However, most metal ions were adsorbed on the filter papers by the formation of hydroxide in neutral solution. The adsorption of metal ions except $Ag^+$ ion could be avoided depend on the acid concentrations.

• Carbon letters
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• v.7 no.2
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• pp.97-104
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• 2006

The influence of carbon surface area, carbon-oxygen groups associated with the carbon surface and the solution pH on the adsorption of Pb(II) ions from aqueous solutions has been studied using three activated carbons. The adsorption isotherms are Type I of BET classification and the data obeys Langmuir adsorption equation. The BET surface area has little effect on the adsorption while it is strongly influenced by the presence of acidic carbon oxygen surface groups. The amount of these surface groups was enhanced by oxidation of the carbons with different oxidizing agents and reduced by eliminating these groups on degassing at different temperatures. The adsorption of Pb(II) ions increases on each oxidation and decreases on degassing the oxidized carbons. The increase in adsorption on oxidation has been attributed to the formation of acidic carbon-oxygen surface groups and the decrease to the elimination of these acidic surface groups on degassing. The adsorption is also influenced by the pH of the aqueous solution. The adsorption is only small at pH values lower than 3 but is considerably larger at higher pH values. Suitable mechanisms consistent with the adsorption data have been suggested.

• Journal of Environmental Science International
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• v.22 no.12
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• pp.1651-1660
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• 2013

The adsorption of lithium ion onto zeolite was investigated depending on contact time, initial concentration, cation forms, pH, and adsorption isotherms by employing batch adsorption experiment. The zeolite was converted into different forms such $K^+$, $Na^+$, $Mg^{2+}$, $Ca^{2+}$, and $Al^{3+}$. The zeolite had the higher adsorption capacity of lithium ion in $K^+$ form followed by $Na^+$, $Ca^{2+}$, $Mg^{2+}$, and $Al^{3+}$ forms, which was in accordance with their elctronegativities. The lithium ion adsorption was explained using the Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms and kinetic models. Adsorption rate of lithium ion by zeolite modified in $K^+$ form was controlled by pseudo-second-order and particle diffusion kinetic models. The maximum adsorption capacity obtained from Langmuir isotherm was 17.0 mg/g for zeolite modified in $K^+$ form. The solution pH influenced significantly the lithium ions adsorption capacity and best results were obtained at pH 5-10.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2471-2476
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• 2014

The aim of the present study is to explore the possibility of utilizing loess for the adsorption of total phosphorous (T-P) and total nitrogen (T-N) in water. Batch adsorption studies were performed to evaluate the influences of various factors like initial concentration, contact time and temperature on the adsorption of T-P and T-N. The adsorption data showed that loess is not effective for the adsorption of T-N. However, loess exhibited much higher adsorption capacity for T-P. At concentration of $1.0mgL^{-1}$, approximately 97% of T-P adsorption was achieved by loess. The equilibrium data were fitted well to the Langmuir isotherm model. The pseudo-second-order kinetic model appeared to be the better-fitting model because it has higher $R^2$ compared with the pseudo-first-order and intra-particle kinetic model. The theoretical adsorption equilibrium $q_{e,cal}$ from pseudo-second-order kinetic model was relatively similar to the experimental adsorption equilibrium $q_{e,exp}$. The thermodynamic parameters such as free energy ${\Delta}G$, the enthalpy ${\Delta}H$ and the entropy ${\Delta}S$ were also calculated.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.539-546
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• 2017

In this study, an outstanding anion exchange chemical filter was prepared for acidic gas removal. Commercial anion exchange resin was attached to polyurethane (PU) foam by using different types of pressure sensitive adhesive (PSA). The water and chemical resistance and also adhesive elongation were investigated. Also, the behavior of HCl and HF adsorption was evaluated as functions of the initial concentration and flow rate. ATE-701, AT-4000C and HCA-1000 showed 900, 1,500% and 2,400% of the elongation, respectively. It was confirmed that the desorption ratio of HCA-1000 was less than 6% and had excellent durability in water and chemical resistance tests. The adsorption occurred faster as the concentration and flow rate of HCl and HF increased. But 100% adsorption equilibrium occurred after 110 minutes, regardless of the concentration and flow rate. In addition, SEM morphology showed that the adhesive was uniformly dispersed, while the porous structure of the ion exchange resin was maintained, and the chemical filter exhibited excellent durability for the adsorption/desorption process.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.920-923
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• 1998

In this work, the adsorption characteristics of the activated carbon treated with 30 wt. %HCl and 30 wt. % NaOH were investigated. The acid and base values were determined by Boehm's method and the surface area and porosity was measured by BET-method with $N_2$-adsorption. Also, the adsorption characteristics of the activated carbons treated with acid and base chemical solutions were investigated with $CO_2$ and $NH_3$-adsorption. From which, relatively different adsorption behaviors of the modified activated carbons were observed in the amounts of $CO_2$ and $NH_3$ adsorptions, even though the physical surface structures of the activated carbons, such as specific surface area, pore size and pore volume, were not significantly changed.

• Journal of the Korean Chemical Society
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• v.9 no.4
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• pp.185-189
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• 1965

Korean acid clays and silica gel were put into action on benzene solution of dye, such as aniline yellow, o-nitro aniline and oil orange, and then the adsorptivity of dye in nonaqueous solution was measured, with the result that adsorptivity was greater with silica than acid clays and it had no relation to acidity. And when chemical compounds, such as amine, alcohol, halogen derivative, were added to each dye solution by 10%(in volume), the change of the adsorptivity of dye by solid acid(that is, the interfered adsorption rate) decreased in order of amine > alcohol > halogen derivative, and in homologue the smaller the molecular weight, the larger was the effect. So adsorption in nonaqueous solution was a selective adsorption of chemical compounds which contained negative groups such as amine and hydroxyl radicals, and it had no relation to surface tension and showed inverted phenomenon of Traube series. It is guessed that the inverted phenomenon (the interfered adsorption phenomenon) was due to the polar chemical adsorption between active $SiO_2$ which was an origin of solid acid and the adsorbed substances, considering that the order of inversion was nearly in accord with dipole moment of added solvents. The results of this study led to find adsorption mechanism and inverted phenomenon of Traube series in nonaqueous solution.

• Journal of the Korean Chemical Society
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• v.36 no.3
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• pp.351-359
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• 1992

Interaction of xenon with alkaline-earth cations in Y zeolite supercage was studied by xenon adsorption and $^{129}Xe$ NMR experiments. The CaY and the BaY samples were prepared by exchanging $Ca^{2+}$ and $Ba^{2+}$ into a high-purity NaY zeolite. Xenon adsorption isotherms of these samples were obtained by using a conventional volummetric gas adsorption apparatus in the range of 260 to 320 K and the chemical shift in the $^{129}Xe$ NMR spectrum of the adsorbed xenon was measured at 296 K. The chemical shift against pressure was quantitatively explained assuming that the xenon gas exchanged very rapidly between various adsorption sites consisting of zeolite-framework surface and alkaline-earth ion. From this analysis, it was found that the alkaline-earth ion adsorbed xenon more strongly than $Na^+$ ion and zeolite-framework surface. Baring on the difference of the adsorption strength, the number of the alkaline-earth cations present in the zeolite supercage could be estimated by analyzing the adsorption isotherm.

• Journal of Environmental Science International
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• v.14 no.1
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• pp.61-69
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• 2005

Adsorption characteristics of toluene vapor, which is one of important source of volatile organic compounds (VOCs), by activated carbon were investigated using a fixed bed adsorption column. The operating parameters such as breakthrough curve, adsorption capacity, mass transfer zone (MTZ), and length of unused bed (LUB) were studied. The experimental results showed that the breakthrough time decreased with increasing inlet toluene concentration and gas flow rate. MTZ and LUB increased with the increase of inlet concentration, gas flow rate, and particle size of activated carbon. The adsorption capacity increased with the increase of inlet toluene concentration, while it decreased with increasing particle size. However, it was kept at constant value regardless of the increase of gas flow rate. Adsorption isotherm of toluene vapor could be represented by the Freundlich adsorption equation fairly well. From the adsorption experiments using some VOC gases such as toluene, xylene, butyl acetate. butanol and acetone, it was also found that the adsorption capacity was higher in the case of gas with higher boiling point and lower vapor pressure.