• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1936-1938
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• 2011

Phosphonium montmorillonites (P-MMTs) were prepared by intercalating dodecyl tributyl phosphonium salt into sodium montmorillonite (Na-MMT) through an ion-exchange method. Microstructure and antibacterial activity of phosphonium montmorillonites were studied by FT-IR, TGA, XRD and Minimum Inhibitory Concentration (MIC), respectively. The results show that phosphonium montmorillonites exhibit higher thermal stability than conventional ammonium montmorillonites, the onset temperature of decomposition is higher than 300 $^{\circ}C$, and the basal spacing of phosphonium montmorillonites is enlarged compared to that of sodium montmorillonite. Phosphonium montmorillonites also show good antibacterial activity with the MIC against E. coli and S. aureus of 150 and 50 $mg{\cdot}L^{-1}$, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.43-52
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• 2000

Deodorization characteristics and removal rate of sulfur-containing odor have been investigated in the soil filter reactors packed with montmorillonites (Mont.), rice hulls(Rh.), and thickening-activated sludge(Ts.). And variation of pH and $SO_4{^{2-}}$ with the removal of malodorous sulfur compounds have been investigated together. As compared removal rate of montmorillonites between wet and dry condition for sulfur compounds through batch test, it showed that wet condition was better than dry one; removal ratio, as wet/dry, was $H_2S$ of 1.2 and $CH_3SH$ of 1.9, and decrease of pH and increase of $SO_4{^{2-}}$ concentration in the wet condition also showed to be larger than in dry condition. In continuous test for biological deodorization experiment, removal rate of sulfur compounds in reactor packed with Mont., Rh. and Ts, was more than 98 %, and the variation of static pressure was maintained stably under condition of SV $150h^{-1}$, LV 4.2 mm/sec and SV $200h^{-1}$, LV 5.6 mm/sec, and in reactor packed with Mont. and Rh., $H_2S$ was 76.4 % to 87.2 % and $CH_3SH$ was 87.8 % to 93.3 % under the same condition. From above results, it ascertained that it can obtain the high deodorization efficiency by inoculating thickening-activated sludge in soil filter using montmorillonites.

• Economic and Environmental Geology
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• v.19 no.spc
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• pp.131-138
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• 1986

Hydrogen and oxygen isotope ratios of thirteen of the under 2 micron size fraction of the montmorillonites were measured. The oxygen isotopic compositions of these samples range from + 17.0 to +25.1 permil and the hydrogen isotope compositions range from -47.5 to -65.8 permil with an average standard deviation of 0.7 and 2.7 permil, respectively. The oxygen isotope compositions show a positive relationship with stratigraphy whereas the hydrogen isotope compositions do not. It suggest that the montmorillonite attained isotopic equilibrium at the maximum burial depth and ratained their oxygen isotope composition on subsequent uplift. Possibilities of montmorillonite formation by weathering or hydrothermal alteration of volcanic material are eliminated by the ${\delta}D$ and ${\delta}^{18}O$ values of these samples. Calculated formation temperature lie between 29 to $80^{\circ}C$.

• Polymer(Korea)
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• v.27 no.4
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• pp.392-395
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• 2003

Phosrhonium salt exchanged montmorillonites were prepared from a reaction between alkyl triphenyl phosponium bromide and Na$^{＋}$-montmorillonite. Epoxy-clay nanocomposites were also prepared by using cycloaliphtic epoxy, methyl tetrahydrophthalic anhydride as a hardener, and triphenyl butyl phosphonium bromide as an accelerator. TEM and XRD results suggested that clay minerals in the epoxy-montmorillonites composite were intercalated. Mechanical properties such as tensile modulus and strength were measured and the effect of nanocomposite formation was also discussed.

• Economic and Environmental Geology
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• v.22 no.3
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• pp.207-219
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• 1989

Eight under 2 micron size fractions of the montmorillonite from Jugjeonri area, Gyeongsanbug-do, were studied and then this result has been compared with data from Yongdongri area. Montmorillonites occurring at the same stratigraphic horizon in each area show limited variation in chemical composition, but shows some degree of differences in exchangeable cation compositions and total layer charges of montmorillonites from Jugjeonri to Yongdongri area. In general, samples from Jugjeonri show higher amount of exchangeable Na and layer charge due to relatively higher substitution of Mg for Al in octahedral sites than those from Yongdongri area. But Their dehydroxylation endothermic peaks of the samples from both areas are abnormal type with a small range of variation of peak temperature. This variation seems to reflect tetrahedral substitution of AI for Si for samples from Yongdongri whereas samples from Jugjeonri do not show shuch a tendency. However, samples from Jugjeonri proved to be relatively higher dehydroxylation peak temperatures than those of the other. DSC data for sample from Jugjeonri also show that divalent-cation saturated montmorillonite have relatively a higher endothermic heat capacities than monovalent-cation saturated one as shown in previous work. Two different morphologies of montmorillonites, honeycomb structure and closely packed intergrowth, by SEM were observed in samples from both areas but the later one is common. The scalloped type is relatively abundant in the sample from Yongdongri than the other. The dominant habit by TEM are irregularly shaped foliated aggregates and platy shaped particles. In general, foliated aggregates which are easy to disperse are relatively abundant in the samples from Jugjeon compared with those from Yongdongri area.

• Journal of the Mineralogical Society of Korea
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• v.1 no.2
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• pp.117-130
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• 1988

The morphology of the Ca-montmorillonites from the Gampo area was investigated by the use of scanning and transmission electron microscope. These bulk samples show an irregular or rugged surface with well developed cavities and relict outline of original ash material at low magnification by SEM, indicating that montmorillonites are derived from volcanogenic material. Two different types of morphology of montmorillonites by SEM were observed which appear to depend very much on the space available for crystal growth. One is honeycomb structure montmorillonite growing in an open space. The other is the closely packed aggregates of intergrown montmorillonite showing platy particles where available space for the growth is limited. Several different habits of montmorillonite within a single sample can be observed by TEM. The dominant habit observed is the irregularly shaped and foliated aggregates and the platy shaped particles. In general, platy shaped particles are relatively abundant in the samples from Yongdongri compared with those from Jugjeonri area.

• Polymer(Korea)
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• v.27 no.2
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• pp.129-134
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• 2003

It has been known that the intercalation of long alkyl chains in montmorillonites (MMT) increased the hydrophobicity as well as gallery spacing of UT, which has influenced on the exfoliation behavior of various polymers. A series of organophilic MMTs were synthesized from the water/isopropyl alcohol solution of MMT with ammonium salts of various alkyl amines. The properties of obtained MMTs such as thermal decomposition temperature, gallery spacing as well as hydrophobic property were investigated. The X-ray diffraction experiments on organophilic montmorillonite demonstrated that the increase of length of alkyl substituent resulted in increase in the spacing between silicate layers, which was ranged from 13.1 to 29.4 $\AA$. On the other hand, introduction of (di-, tri-) alkyl substituents in ammonium salts decreased water absorption of organophiplic montmorillonite to 2.7%.

• Economic and Environmental Geology
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• v.18 no.3
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• pp.253-261
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• 1985

Detailed chemical compositions of thirteen montmorillonites and their thermal behaviour by differential thermal and thermogravimetric analysis have been studied. Comparison of structural formulae with experimental results by thermal analysis gave evidence of that both substitutions of Fe for Al in octahedral and Al for Si in tetrahedral positions appear to affect dehydroxylation temperature, which is valid for the present samples. Further detailed study of this topic using well-known samples which have various degree of substitution will be justified.

• Polymer(Korea)
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• v.27 no.2
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• pp.135-141
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• 2003

A series of organophilic montmorillonites (MMTs) modified with various alkyl siloxane amino oligomer groups have been synthesized and their properties were investigated. New organophilic MMTs containing siloxane amino oligomers with alkyl group instead of conventional alkyl amines were synthesized to improve thermal stability as well as gallery spacing. The organophilic MMTs were synthesized from MMT by utilizing the siloxane amino oligomers with various alkyl groups in the water/dioxane solution, which was performed without aq. HCl. Thermal decomposition temperature, gallery spacing, and hydrophobicity of synthesized organophilic MMTs were investigated. X-ray diffraction and TEM experiment results on new organophilic MMTs demonstrated that introduction of siloxane amine oligomers increased d-spacing between silicate layers. The decomposition temperatures of new organophilic MMTs measured by TGA was remarkably improved above 200℃ as compared with those of conventional alkyl substituted organophilic MMTs.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.965-968
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• 2004

H-montmorillonite was modified by interlayer surface silylation using 3-aminopropyltriethoxysilane and dodecylamine in ethanol without a pre-swelling step. Dodecylamine acts as a gallery expander and silylation catalyst. The evaporation of ethanol from the dispersion yields well-ordered silylated montmorillonites with large basal spacing between 1.50 and 4.20 nm. Solid-state $^29Si$ CP MAS NMR of the silylated samples showed $Q^2\;and\;Q^3$ signals as well as $T^2\;and\;T^3$ signals. The increase in the relative intensity of $Q^3\;for\;Q^2$ and the appearance of $T^2\;and\;T^3$ signals was attributed to the grafting of 3-aminopropyltriethoxysilane to the interlayer surface silanol groups.