• Korean Journal of Soil Science and Fertilizer
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• v.25 no.2
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• pp.111-126
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• 1992

Silica sorption isotherm belonged to the C-type with weak L-type characteristics according to the classification system of adsorption isotherm. Silica sorption isothem fitted well to the Freundlich and Tempkin equation but not to the Langmuir equation. The color interference probably due to $Fe^{2+}$ during spectrometric silca determination by Molybdenum-blue method affected the sorption isotherm in reduced soils or low pH. Four parameters such as the intercept of Freundlich equation, the slope of Tempkin equation, the "Silica reactivity", and the "C-type slope", where the last two parameters were termed in the current study, were examined to assess treatment effects on silica sorption. Among them the "C-type slope" was found out to be the best parameter. The C-type isotherms showed the same high correlation coefficient as Freundlich and Tempkin equation when regressed to the sorption isothem. Plotting the C-type slope on a logarithmic scale vs. the pH showed high linearity. Using the "C-type slope" as a perameter, the pH and soil type affected the silica sorption while the effect of redox condtion was not significant. All Fe and Al extracted by the various reagents, and OM were highly correlated to silica sorption. Among them $Fe_d$ was identified as the highest influencing soil property. Since there is no equivalent reliable method to discriminate the forms of the soil Al-oxides their likely importance remains unclear.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.621-627
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• 2013

In order to apply eco-friendly poly(propylene carbonate) (PPC) into barrier packaging materials, six different PPC/exfoliated graphite (EFG) nanocomposite films with different EFG were successfully prepared by a solution blending method. Their water sorption behavior was gravimetrically investigated as a function of the EFG content and interpreted with respect to their chemical structure and morphology. The water sorption isotherms were reasonably well fitted by Fickian diffusion model, regardless of morphological heterogeneities. With increasing the EFG content, the diffusion coefficient and water uptake decreased from $12.5{\times}10^{-10}cm^2sec^{-1}$ to $7.2{\times}10^{-10}cm^2sec^{-1}$ and from 8.9 wt% to 4.2 wt%, respectively, which indicates that the moisture resistance capacity of PPC was greatly enhanced by incorporating EFG into PPC. The enhanced water barrier property of the PPC/EFG nanocomposite films with the high aspect ratio EFG makes them potential candidates for versatile packaging applications. However, to maximize the performance of the nanocomposite films, further researches are required to increase the compatibility of EFG in the PPC matrix.

• Journal of the Korean Wood Science and Technology
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• v.19 no.4
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• pp.52-61
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• 1991

In this paper, the difference of the property of absorption and desorption for five species in semi-steady state are studied. The species used are listed in Table 1 and the dimension of specimen was $8\times8{\times}T$(Tangential direction)cm and tested in various conditions. A change of average moisture content with time were measured in each cycles. The results obtained are summarized as follows. When the relative humidity in air was maximum or minimum, the distribution of moisture In wood of all specimens were illustrated by exponential curves of decrease or increased from lace 10 center of wood. From the consideration of coefficient of decrease(C), the amount of moisture change of spruce was larger than the others. The pheonomenon was considered no relation to the specific gravity in air dry, but the wood structures. The velocity of the absorption and desorption for species decreased in the order spruce(Picea sitchensis) neodobam(Fagus crenata), solsong(Tsuga heterophylla), meranti(Shorea sp.) and kaesoo(Cercidiphyllum japoicum). In case of constant temperature and water vapor pressure is changed. the amount of absorbed moisture was larger than that of constant water vapor pressure and temperature vaned. In this fact, it is considered that the property of sorption of wood is strongly influenced by vapor pressure gradient than temperature gradient.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.2
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• pp.38-46
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• 2008

Many researchers have reported that many biopolymers making up cell walls of the microorganisms display an ion-exchange property and play a major role in the sorption of the metal ions. Such polymers derived from microbial biomass are potentially useful as biosorbent materials for recovery various metal ions in industrial applications. although synthetic polymers such as ion-exchange resins and chelating resins have been widely used as commercial sorbents. In this study, valuable and commercial biopolymers for metal removal will be introduced.

• Environmental Engineering Research
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• v.22 no.4
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• pp.356-362
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• 2017

This study investigates the use of methyl-esterified eggshell membranes (MESM) for the harvesting of microalgae species under various conditions. Eggshell membranes were esterified with HCl to impact polycationic characteristics. After methyl esterification, the negative surface charge property of eggshell membrane was changed from negative to positive for all pH values to improve microalgae sorption capacity. The harvesting efficiency of microalgae by MESM reached 78-99% for all pH ranges evaluated. In addition, a 150 mesh particle size and $10mg\;L^{-1}$ MESM dose were found to yield up to 98% microalgae harvesting. These results indicate that the high cationic charge of MESM strongly adsorbs the negatively-charged microalgae. MESM is biocompatible and can be applied to the harvest of microalgae.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.125-126
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• 2006

We show that thermal rearrangement of glassy polymers below the thermal degradation temperature can create unexpected and large microvoids in the membranes, leading to unexpected high gas permeability with high gas selectivity. These current polymer membranes display unexpected gas permeation-separation performance. There are above the upper-bound for conventional polymer membranes for several gas pairs. In the present study, molecular simulation, BET sorption, positron annihilation lifetime spectroscopy (PALS), and gas separation experiments were performed to characterize the unusual structure-property relationship of these rigid glassy polymer membranes.

• Journal of Korean society of Dental Hygiene
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• v.19 no.2
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• pp.173-181
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• 2019

Objectives: The resin infiltration technique is a promising alternative therapy for arresting the early dental caries. However, there are very few reports on the safety and biocompatibility of this technique. We evaluated various properties of resin infiltrant (RI) based on a triethylene glycol dimethacrylate (TEGDMA).The water sorption (Wsp) and water solubility (Wsl) was assessed. Additionally, the cytotoxicity of RI against both animal and human fibroblast cell lines was investigated. Methods: The RI of the $Icon^{(R)}$, the first product developed for resin infiltration, is mainly composed of TEGDMA in the resin matrix. The Wsp and Wsl for the RI were measured in accordance with ISO 4049 specifications. Fourier-transform infrared spectroscopy (FTIR) was used for analyzing the polymerization before and after curing of RI. The cytotoxicity of RI against the mouse fibroblasts (L929) and human gingival fibroblasts (hTERT-hNOF) was evaluated using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and the data were analyzed using one-way analysis of variance. Results: Wsp and Wsl of the RI specimens were $53.37{\mu}g/mm^3$ and $10.6{\mu}g/mm^3$, respectively. FTIR analysis revealed a slightly higher degree of curing with longer irradiation time. The degree of conversion for RI was high (80.9%) after 40 seconds of light curing. There was a significant decrease in the viability of L929 and hTERT-hNOF cells at RI extraction solution concentrations above 50%, respectively, compared to that in the negative control (p< 0.05). Conclusions: Even though the RI exhibited positive effect on the early prevention of dental caries, the clinicians should also consider the toxicity of RI on periodontal tissues.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.4
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• pp.259-269
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• 2013

Applicability of ammonium molybdophosphate/iron oxides-polyacrylonitrile (AMP/IO-PAN) composites on the removal of radionuclides in the radioactive wastewater generated from nuclear power plants was investigated. The composites were characterized using the following analytical techniques: X-ray diffraction (XRD), Fourior transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), particle size analyzer (PSA), nitrogen adsorption-desorption and magnetic property measurement system (MPMS). 10wt% of AMP/IO-PAN composite has a saturation magnetization of 2.038 emu/g. Single-solute sorptions of Co, Sr and Cs onto 10wt% of AMP/IO-PAN composite were investigated. The maximum sorption capacities ($Q^0$) predicted by the Langmuir model on 10wt% of AMP/IO-PAN composite were 0.097, 0.086 and 0.66 mmol/g for Co, Sr and Cs, respectively. The maximum sorption capacities ($Q^0$) of Cs predicted by Langmuir model on 0, 10, 20 and 30wt% of AMP/IO-PAN composites were 0.702, 0.655, 0.602 and 0.559 mmol/g, respectively. The maximum sorption capacities ($Q^0$) of Cs decreased with increasing the iron oxide content in the AMP/IO-PAN composites.

• Applied Biological Chemistry
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• v.28 no.2
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• pp.51-55
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• 1985

Dried black soybeans were soaked in water at the temperature range of $4^{\circ}C{\sim}100^{\circ}C$ and in salt or sugar solution at $100^{\circ}C$ in order to investigate their effects on the cooking ratio and diffusion property of color pigments. As the temperature increased, the equilibrated absorbance at 490nm of soaking water after 120min was linearly increased. The activation energy for diffusion of color pigments were found to be 4.23 Kcal/mole at the range of $60^{\circ}C{\sim}100^{\circ}C$ and 8.31 kca1/mo1e at $4^{\circ}C{\sim}60^{\circ}C$. The cooking ratio, % cooked beans after heating, of black soybeans were more affected by the salt concentration that of sugar. Both concentrations reduced the cooking ratio as they increased. The sorption isotherm of Kongjaban showed a quite different curves between the storage at $4^{\circ}C$ and $25^{\circ}C$. The sorption and desorption rates during storage could be represented by the equation of $log({\frac{dw}{dt}}{\times}10^3))=alogt+logb$ with a very high correlation.

• Economic and Environmental Geology
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• v.51 no.6
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• pp.531-542
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• 2018

Batch sorption experiments were performed to remove the uranium (U) in groundwater by using the bamboo charcoal. For 2 kinds of commercialized bamboo charcoals in Korea, the U removal efficiency at various initial U concentrations in water were investigated and the optimal sorption conditions to apply the bamboo charcoal were determined by the batch experiments with replicate at different pH, temperature, and reaction time conditions. From results of adsorption batch experiments, the U removal efficiency of the bamboo charcoal ranged from 70 % to 97 % and the U removal efficiency for the genuine groundwater of which U concentration was 0.14 mg/L was 84 %. The high U removal efficiency of the bamboo charcoal maintained in a relatively wide range of temperatures ($10{\sim}20^{\circ}C$) and pHs (5 ~ 9), supporting that the usage of the bamboo charcoal is available for U contaminated groundwater without additional treatment process in field. Two typical sorption isotherms were plotted by using the experimental results and the bamboo charcoal for U complied with the Langmuir adsorption property. The maximum adsorption concentration ($q_m:mg/g$) of A type and C type bamboo charcoal in the Langmuir isotherm model were 200.0 mg/g and 16.9 mg/g, respectively. When 2 g of bamboo charcoal was added into 100 mL of U contaminated groundwater (0.04 ~ 10.8 mg/L of initial U concentration), the separation factor ($R_L$) and the surface coverage (${\theta}$) maintained lower than 1, suggesting that the U contaminated groundwater can be cleaned up with a small amount of the bamboo charcoal.