• Journal of the Korean Ceramic Society
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• v.41 no.1
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• pp.41-44
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• 2004

Hydrophilicity and hydrophobicity of pottery bodies can be controlled via chemical substitution of layered clay with hydrophilic and hydrophobic organics. In this study, organo-clay nanocomposites were prepared by ion-exchange of montmorillonite with dodecylamine and hexadecylamine, respectively. Substitution sites of organics and the interval changes of layered materials are characterized by FT-IR and WAXD and organics amounts loaded and water comtents contained by C/S analysis and TG-DSC. The organics were selectively intercalated so that increase layer interval from 12${\AA}\; to\;16{\AA}$. Organo-modified clay is changed to more hydrophobic comparing to clay itself.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2968-2972
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• 2013

A highly efficient and environmentally benign protocol has been developed for the first time to produce a wide range of biologically active 5-hydroxyindole derivatives using montmorillonite KSF clay as a reusable solid acid catalyst. The use of recyclable clay makes this procedure quite simple, more convenient and cost-effective.

• Environmental Engineering Research
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• v.20 no.2
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• pp.133-140
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• 2015

The aim of this study was to investigate the bacteriophage removal in various clay minerals and clay-amended soils. Batch experiments in kaolinite, montmorillonite, and bentonite showed that kaolinite was far more effective at the MS2 removal than montmorillonite and bentonite. In kaolinite, the log removal increased from 0.046 to 2.18, with an increase in the adsorbent dose from 0.3 to $50g\;L^{-1}$, whereas the log removals in montmorillonite and bentonite increased from 0.007 to 0.40 and from 0.012 to 0.59, respectively. The MS2 removal in kaolinite-amended silt loam soils was examined at three different soil-to-solution (STS) ratios. Results indicated that the log removal of MS2 increased with an increase in the kaolinite content and the STS ratio. At the STS ratio of 1:10, the log removal of MS2 increased from 2.33 to 2.80 with an increase in the kaolinite content from 0% to 10% in kaolinite-amended soils. The log removals of MS2 at the STS ratios of 1:2 and 1:1 increased from 2.84 to 3.47 and from 3.46 to 4.76, respectively, with an increase in the kaolinite content from 0% to 10%. Results also indicated that the log removals of PhiX174 and $Q{\beta}$ in kaolinite-amended soils were similar to each other, but they were far lower than those of MS2 at all the kaolinite contents. The log removal of PhiX174 increased from 0.16 to 0.32, whereas the log removal of $Q{\beta}$ changed from 0.17 to 0.22 with an increase in the kaolinite content from 0% to 10%.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.545-550
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• 2011

Urea intercalated into montmorillonite (MT) exhibits remarkably enhanced N use efficiency, maintaining its fast effectiveness. This study dealt with the release property of urea from metal-urea-clay hybrid with MT (MUCH) under continuous-flow conditions and the cumulative impacts of its successive application on physicochemical properties of soils. Releases of urea were completed within 4 hrs under continuous-flow condition regardless of the types and the leaching solutions. However, urea release property was significantly affected by both the form of fertilizer and the presence of electrolytes in solution. The fast release property of urea from MUCH in continuous-flow condition was not significantly affected by soil properties such as soil pH and soil texture. In addition, its successive application did not lead to any noticeable change in soil physicochemical properties, water stable aggregate rate, water holding capacity and cation exchange capacity in both sandy loam and clay loam soils. Therefore, this study strongly supported that urea intercalated into MT could be applied as fast-effective N fertilizer, in particular for additional N supply.

• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.305-314
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• 2002

The dehydration of hexadecyltrimethylammonium (HDTMA)-exchanged montmorillonite has been studied using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The dehydration in HDTMA-montmorillonite seems to influence the swelling behavior of the organo-clay during heating. The basal d(001) spacing vs temperature curve of the HDTMA-montmorillonite has one broad swelling edge with a shoulder on the low-temperature side. We believe that the shoulder at $100^{\circ}C$ for the HDTMA-montmorillonite is due to interlayer swelling induced by the initial rearrangement of surfactants, and the second edge at $200^{\circ}C$ is caused by interlayer swelling resulting from the secondary vertical reorientation of alkyl chains. It seems that the dehydration of organo-clay induces a reorientation of the alkyl chains by transition to more vertical position relative to the silicate sheets, allowing instantly greater d-spacing.

• Geomechanics and Engineering
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• v.10 no.6
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• pp.807-826
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• 2016

In this study, aiming to investigate the effects of sulfate attack on cement stabilized highly plastic clay; an experimental study was carried out considering the effects of cement type, sulfate type and its concentration, cement content and curing period. Unconfined compressive strength and chloride-ion penetration tests were performed to obtain strength and permeability characteristics of specimens cured under different conditions. Test results were evaluated along with microstructural investigations including SEM and EDS analyses. Results revealed that use of sulfate resistance cement instead of normal portland cement is more plausible for soils under the threat of sulfate attack. Besides, it was verified that sulfate concentration is responsible for strength loss and permeability increase in cement stabilized montmorillonite. Finally, empirical equations were proposed to estimate the unconfined compressive strength of cement stabilized montmorillonite, which was exposed to sulfate attack for 28 days.

• Journal of the Korean Society of Industry Convergence
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• v.13 no.2
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• pp.93-98
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• 2010

Polypropylene / montmorillonite / wood flour nanocomposites are melt-mixed by using a twin screw extruder. The montmorillonite is intercalated by the wood flour and the basal spacing of montmorillonite is increased with increasing the content of wood flour. The exfoliation constantly occurs by adding more than 10 wt.% of maleic anhydride-grafted polypropylene as the compatibilizer, which is used for improving the interfacial adhesion between matrix and filler. Also, the maleic anhydride-grafted polypropylene enhances the mechanical properties of the nanocomposites.

• Environmental Engineering Research
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• v.14 no.1
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• pp.26-31
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• 2009

Sorption of $Ni^{2+}$ in aqueous solution was studied using montmorillonite. The experimental and equilibrium data fitted well to the Langmuir isotherm model. From the kinetics data for nickel sorption onto montmorillonite, the diffusion of $Ni^{2+}$ inside the clay particles was the dorminant step controlling the sorption rate and as such more important for $Ni^{2+}$ sorption than the external mass transfer. $Ni^{2+}$ was sorbed due to strong interactions with the active sites of the sorbent and the sorption process tends to follow the pseudo second-order kinetics. Thermodynamic parameters (${\Delta}G^{\circ},\;{\Delta}H^{\circ},\;{\Delta}S^{\circ}$) indicated a non spontaneous and endothermic adsorption process while the positive low value of the entropy change suggests low randomness of the solid/solution interface during the uptake of $Ni^{2+}$ by montmorilionite. Heavy metals such as $Ni^{2+}$ in aqueous bodies can effectively be sorbed by montmorillonite.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.747-756
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• 2012

The purpose of this study was to investigate adsorption characteristics of organo-clays for removal of p-xylene. As part of efforts to examine the adsorption capacities of some organo-clays for p-xylene, batch isotherm tests were carried out. Organo-clay minerals were synthesized under hydrothermal conditions using Na-montmorillonite as host clay and dimethyldioctadecylammonium (DMDA) bromide and benzyldimethyldodecylammonium (BDDA) chloride as organic surfactants, respectively. All synthetic organo-clay minerals were characterized by powder x-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDX). The modification using dimethyldioctadecylammonium (DMDA) bromide showed the higher adsorption ability for p-xylene than benzyldimethyldodecylammonium (BDDA) chloride. On the other hand, the maximum adsorption capacity, $Q_{max}$ of DMDA modified montmorillonite estimated by Langmuir model was 27.0 mg/g, which was the higher value than other organo-clays.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.11
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• pp.1614-1621
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• 2013

The aim of this study was to investigate the effects of graded levels of montmorillonite, a constituent of clay, on performance, hematological parameters and bone mineralization in weaned pigs. One hundred and twenty, 35-d-old crossbred pigs (Duroc${\times}$Large White${\times}$Landrace, $10.50{\pm}1.20$ kg) were used in a 28-d experiment and fed either an unsupplemented corn-soybean meal basal diet or similar diets supplemented with 0.5, 1.0, 2.5 or 5.0% montmorillonite added at the expense of wheat bran. Each treatment was replicated six times with four pigs (two barrows and two gilts) per replicate. Feed intake declined (linear and quadratic effect, p<0.01) with increasing level of montmorillonite while feed conversion was improved (linear and quadratic effect, p<0.01). Daily gain was unaffected by dietary treatment. Plasma myeloperoxidase declined linearly (p = 0.03) with increasing dietary level of montmorillonite. Plasma malondialdehyde and nitric oxide levels were quadratically affected (p<0.01) by montmorillonite with increases observed for pigs fed the 0.5 and 1.0% levels which then declined for pigs fed the 2.5 and 5.0% treatments. In bone, the content of potassium, sodium, copper, iron, manganese and magnesium were decreased (linear and quadratic effect, p<0.01) in response to an increase of dietary montmorillonite. These results suggest that dietary inclusion of montmorillonite at levels as high as 5.0% does not result in overt toxicity but could induce potential oxidative damage and reduce bone mineralization in pigs.