• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.678-684
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• 2001

Porous silica-pillared montmorillonites were prepared by simultaneous intercalation of dodecylamine-TEOS [tetraethylorthosilicate, Si(OC2H5)4] into the H-montmorillonite and intragallery amine-catalyzed hydrolysis of TEOS. Mixtures of the H-montmorillonite, dodecylamine and TEOS at molar ratios of 1 : 2 : 15-30 and 1 : 2-6 : 20 resulted to swollen and viscous gel once at room temperature, allowing intercalation compounds which dodecylamine and TEOS were simultaneously intercalated into interlayer of H-montmorillonite. The hydrolysis of the gallery TEOS was conducted in water solution for 40 min at room temperature, affording siloxane-pillared H-montmorillonite. Calcination of samples at 500 $^{\circ}C$ in air resulted in silica-pillared montmorillonite with large specific surface areas between 403 and 577 m2 /g, depending on the reaction stoichiometry. The reaction at H-montmorillonite : dodecylamine : TEOS reaction stoichiometries of 1 : 2 : 15 and 1 : 4 : 20 resulted in high specific surface areas and mesopores with a narrow pore size distribution. Result indicates that the intragallery-amine catalyze the hydrolysis of gallery-TEOS and simultaneously have a role of gallery-templated micellar assemblies.

• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.273-282
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• 2002

Al-pillared montmorillonite was synthesized from Na-saturated montmorillonite which was prepared by ionic substitution from Ca-montmorillonite of the Jabut mine, Gyeongiu City d(001), surface areas, and dehydration and ionic substitution properties have been compared for both Ca-montmorillonite and Al-pillared montmorillonite. d(001) spacings of Ca-montmorillonite and Al-pillared montmorillonite were 15.1 $\AA$ and $18.3\AA$, respectively. Dehydration took place before $350 ^{\circ}C$ in Ca-montmorillonite, whereas linealy up to $550^{\circ}C$ in Al-pillared montmorillonite. BET surface areas are 5～6 times larger in Al-pillared montmorillonite ($192 \m^2$/g) than Camontmorillonite. Ca-montmorilonite shows high selectivity for $Na^{＋}$ /, whereas Al-pillared montmorillonite for $Ca^{2＋}$ . The former shows decreasing d(001) spacing with increasing substitution of $Na^{＋}$ and irregular interstratified structure at high substitution of $Ca^{2＋}$ /, whereas the latter shows linear decreasing pattern in d(001) spacing with increasing $Ca^{ 2+}$.

• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.315-327
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• 2002

Al-pillared clay was synthesized by constructing pillars of aluminum oxides at the interlayer of montmorillonite in bentonite. XRD, DTA and chemical analyses of Al-pillared clay were performed to examine mineralogical properties. Batch adsorption experiments were also conducted to determine the adsorption properties of this synthesized clay for phosphate ions. XRD analyses showed that the interlayer space of Al-pillared clay expanded to 18.03 $\AA$ at room temperature and shifted to $17 \AA$ after heating to $550^{\circ}C$. A small change in interlayer space after heating indicates high thermal stability. The interlayer expansion by glycerol was also very small. From DTA analyses, pillared clay showed the characteristic endothermic peaks at 270 and $420^{\circ}C$ , which might be caused by dehydration in framework of pillars between interlayers. Adsorption experiment revealed that Al-pillared clay had an excellent adsorption capacity to the phosphate ions, whereas montmorillonite had very low adsorption capacity to phosphate ions. In phosphate solution concentration up to 300 mg/L, 2 g of pillared clay could uptake almost 100% of phosphate ions from 20 mL of solution. After heat treatment of the phosphate adsorbed pillared clay at 50$0^{\circ}C$ to remove phosphate, the calcined pillared clay could adsorb phosphate ions with a little decreased adsorption efficiency. This fact indicates that Al-pillared clay can be recycled for the adsorption of phosphate ions.

• Bulletin of the Korean Chemical Society
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• v.19 no.11
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• pp.1185-1188
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• 1998

Layered nanocomposite, SiO2/TiO2 sol pillared clay, has been prepared by the ion exchange reaction of Na' ion in montmorillonite with positively charged mixed SiO2/TiO2 sol. The nanosized sol particles were synthesized by mixing SiO2 sol solution with TiO2 one, which is obtained by acidic hydrolysis of TEOS and TiCl4, respectively. From powder XRD, the basal spacing (d001) of the sample calcined at 400 ℃ was found to be ca. 60 Å, due to the multistacking of nanosized SiO2 and TiO2 sol particles, which was confirmed by the pore size analysis from 129Xe NMR and micropore analysis calculated from nitrogen adsorption. The BET specific surface area shows the value of 684 m2g-1 (Langmuir 1115 m2g-1), which is the highest among various pillared clays ever reported previously, and the total porosity is found to be 0.51 mlg-1, and the pores are mainly composed of micropore with a size of ca. 11.8 Å. This result agrees with the adsorption capacity obtained from water adsorption. According to diffuse reflectance ultraviolet-visible spectroscopy, it is found that the TiO2 particles stabilized in the interlayer space of montmorillonite are quantum-sized of ca. 20 Å.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3005-3012
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• 2013

The effect of Mn-promotion on high surface area Al-pillared montmorillonite (AlMMT) supported Co nanoparticles prepared by hydrothermal method have been investigated. A series of different weight% Mn-promoted Co nanoparticles were prepared and characterized by XRD, TPR, TGA, BET and SEM techniques. An increase in the surface area of MMT is observed with Al-pillaring. Fischer-Tropsch catalytic activity of the as prepared catalysts was studied in a fixed bed micro reactor at $225^{\circ}C$, $H_2/CO$ = 2 and at 1 atm pressure. The data showed that by the addition of Mn the selectivity of $C_1$ dropped drastically while that of $C_2-C_{12}$ hydrocarbons increased significantly over all the Mn-promoted Co/AlMMT catalysts. The $C_{13}-C_{20}$ hydrocarbons remained almost same for all the catalysts while the selectivity of $C_{21+}$ long chain hydrocarbons decreased considerably with the addition of Mn. The catalyst with 3.5%Mn showed lowest $C_{21+}$ and highest $C_2-C_{12}$ hydrocarbons selectivity due to cracking of long chain hydrocarbons over acidic sites of MMT.

• Journal of Korean Society on Water Environment
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• v.34 no.6
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• pp.621-631
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• 2018

In this study, catalyst was made through incipient wetness method using palladium (Pd) as noble metal, indium (In) as secondary metal, and montmorillonite (MK10) and Al pillared montmorillonite (Al-MK10) as supporters. The nitrate reduction rate of the catalysts was measured by batch experiments where H2 gas was used as reducing agent and formic acid as pH controller. Transmission electron microscopy (TEM) equipped with energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were all used to determine the elemental distribution of Pd, In, Al, and Si on catalysts. It was observed that Al pillaring increased the Al/Si elemental composition ratio and point of zero charge of MK10, but decreased its BET specific surface area and pore volume. The nitrate reduction rate of Al-MK10 Pd/In was 2.0 ~ 2.5 times higher than that of MK10 Pd/In using artificial groundwater (GW) in ambient temperature and pressure. Nitrate reduction rates in GW were 1.2 ~ 1.7 times lower than those in distilled deionized water (DDW). Nitrate reduction rates in acidic conditions were higher than those in neutral condition in both GW and DDW. The amount of produced NH3-N over degraded NO3- at acid conditions was lower than that of neutral condition. Even though the leaching of Pd after reaction was measured in DDW it was not detected when both Al-MK10 Pd/In and MK10 Pd/In were used in GW. The modification of montmorillonite as a supporter significantly increased the reductive catalytic activities of nitrates. However, the ratio of producing ammonia by-products to degraded nitrates in ambient temperature and pressure was similar.

• Bulletin of the Korean Chemical Society
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• v.21 no.10
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• pp.1049-1051
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• 2000

A chromia-pillared clay has been prepared by ion exchange type intercalation reaction between the sodium ion in montmorillonite and the trimeric chromium oxyformate (TCF) ion, and by subsequent heat-treatment. The structural and thermal properties have been systematically studied by thermal analysis, powder XRD, IR spec-troscopy, and XAS. The gallery height of~6.8 $\AA$ upon intercalation of the TCF ion suggests that the $Cr_3O$ plane is parallel to the aluminosilicate layers. Even though the basal spacing of TCF intercalated clay decreases slightly upon heating, the layer structure was retained up to $550^{\circ}C$ as confirmed by XRD and TG/DTA. Ac-cording to the EXAFS spectroscopic analysis, it is identified that the (Cr-Cr) distance of 3.28 $\AA$ between vertex-linked CrO6 octahedra in TCF splits into 2.64 $\AA$, 2.98 $\AA$, and 3.77 $\AA$ due to the face-, edge-, and corner-shared CrO6 octahedra after heating at $400^{\circ}C$, implying that a nano-sized chromium oxide phase was stabilized within the interlayer space of clay.

• Journal of the Korean Ceramic Society
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• v.41 no.1
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• pp.81-85
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• 2004

Nanoporous materials with nanometer-sized pores, are of great interest in the various applications such as selective adsorbents, heterogeneous catalysts and catalyst supports because of their high porosity, surface area, and size selective adsorption properties. This study is aimed to prepare nanoporous catalytic materials on the basis of two-dimersional clay by pillaring of $SiO_2$ sol particles. $SiO_2$ Pillared Montmorillonite (Si-PILM) was prepared by ion exchanging the interlayer $Ni^{2+}$ ions of clay with $SiO_2$ nano-sized particles of which the surface was modified with nicked polyhydroxy cations sach as $Ni_4(OH)_4^{4+}$. Nano-sized $SiO_2$ particles were formed by the controlled hydrolysis of tetraethyl orthosilicate (TEOS). Upon pillaring of $Ni^+$-modified $SiO_2$ nano particles between the clay layers, the basal spacing was expanded largely to $45{\AA}$ and the extremely large specific surface area ($S_{BET}$) of $760m^2/g$ was obtained.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2870-2874
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• 2011

Soil pollution around railroad has been occurred mainly by diesel and lubricant oil, which is difficult to treat due to high carbon number. In this study, we investigated the feasibility of inorganic-inorganic nanohybrid photo-catalyst for the remediation of diesel-contaminated railroad soil. Generally, the $TiO_2$ nanoparticle easily removes organic pollutants due to photo and natural clay of layer structure. Also, montmorillonite (MMT) have an excellent absorption property with organic component. So, we prepared $TiO_2$ pillared MMT nanohybrid photo-catalyst as a chemical oxidant through the integration of theses advantage. As a result, the removal efficiency of diesel was more than 45% at a laboratory-scale test with diesel concentration and the amount of $TiO_2$-MMT. In future, we will improve the removal efficiency of diesel to optimize experimental parameters and apply the field soil The remediation method using photo-catalyst can be used to clean up the railroad soil polluted with high concentration instead of common methods such as soil washing, bioremediation, etc..