• Journal of the Korean GEO-environmental Society
• /
• v.13 no.6
• /
• pp.27-31
• /
• 2012

This study was designed to examine the feasibility of functionalized mesoporous silica as the adsorbent for benzene, toluene, ethylbenzene, and xylene isomers (BTEX) in groundwater. p-Xylene was used as the model compound of BTEX. A series of functionalized mesoporous silica with MCM-41 type of structure was synthesized using a co-condensation method. Monoamine, triamine, nitrile, phenyl, and octyl groups were functionalized to the mesoporous silica structure. Adsorption sites for p-Xylene in a functionalized mesoporous silica were Si-O-Si covalent bond, the surfactant, and the functional group. Octyl-functionalized mesoporous silica with stearyltrimethylammonium chloride as a surfactant showed the highest adsorption ability. The maximum xylene adsorption capacity of the octyl-functionalized mesoporous silica with stearyltrimethylammonium chloride based on Langmuir model was 4.17 mmol/g on $20^{\circ}C$, which was 2.9 times higher than that of MCM-41.

• Applied Chemistry for Engineering
• /
• v.27 no.2
• /
• pp.190-194
• /
• 2016

Tricyclopentadiene (TCPD) is one of the important precursors for making tetrahydrotricyclopentadiene, which is well known as a next-generation fuel with high energy density. In this study, TCPD was obtained by polymerization reaction of dicyclopentadiene (DCPD) using an ionic liquid (IL) supported mesoporous silica catalysts. ILs were supported to two kinds of mesoporous silica catalysts with different pore sizes such as MCM-41 and SBA-15. Four different ILs were supported to mesoporous silicas using anionic precursors such as CuCl or $FeCl_3$ and cationic precursors such as triethylamine hydrochloride or 1-butyl-3-methylimidazolium chloride. We proved that IL supported mesoporous silicas showed better catalytic performance than those of using non-supported prestine IL in the aspect of TCPD yield and DCPD conversion. Among four kinds of IL supported mesoporous silica catalysts, CuCl-based IL supported MCM-41 system showed the highest TCPD yield.

• Applied Chemistry for Engineering
• /
• v.10 no.7
• /
• pp.1096-1098
• /
• 1999

MCM-41 type spherical mesoporous silica material was synthesized, under basic conditions, in the presence of cationic surfactant as templating species. The cationic surfactants used in this experiment were octyltrimethylammonium bromide, dodecyltrimetylammonium bromide, cetyltrimethylammonium bromide, octadecyltrimethyammonium bromide and cetylpyridium bromide. Specific surface area of spherical MCM-41 was as high as $1500m^2/g$ and the pore size decreased with increasing alkyl chain length of surfactant.

• Korean Chemical Engineering Research
• /
• v.44 no.3
• /
• pp.248-253
• /
• 2006

In order to develope an efficient drug delivery system, experimental researches on the supercritical impregnation of ibuprofen onto mesoporous silica, MCM-41,and its drug release characteristics were performed. Supercritical carbon dioxide was adapted as an alternative solvent as it is harmless and able to avoid defects of organic solvents in drug manufacturing processes. The procedure was composed of three steps, that is, as hydrothermal synthesis of MCM-41, supercritical impregnation of ibuprofen onto MCM-41 and release of impregnated ibuprofen. Supercritical impregnation reached equilibrium within 2 h for all cases of this research and the amount of equilibrium impregnation increased with solubility of ibuprofen in supercritical carbon dioxide. Release profiles of impregnated ibuprofen showed a similar behavior for all MCM-41 with different impregnated ibuprofen.

• Analytical Science and Technology
• /
• v.19 no.3
• /
• pp.211-217
• /
• 2006

Diphenyl amine (DPA) was polymerized inside the channels of the mesoporous silica (MCM-41). MCM-41 (C) and MCM-41 (D) were prepared with cetyltrimethyl ammonium bromide (CTAB) and dodecyltrimethyl ammonium bromide (DTAB), respectively and used as hosts. Initially, the self assembly of DPA inside the pores of MCM-41 was made in ${\beta}$-naphthalene sulfonic acid (NSA) medium and subsequently poly (diphenylamine), PDPA was formed by oxidative polymerization. $N_2$ adsorption-desorption measurements of PDPA loaded MCM-41 (C) and MCM-41 (D) show variations in pore volume and surface area between them. A tubular form of poly (diphenylamine), PDPA was envisaged to form in the pores of MCM-41 and supported by high resolution transmission microscopy. The presence of PDPA inside the channel of MCM-41 was further confirmed by FTIR spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.4
• /
• pp.1915-1922
• /
• 2012

In this study, synthesis of mesoporous silica such as, SBA-15, MCM-41, MCM-48, KIT-6 according to various experimental conditions. The CMK(Carbon Mesoporous Korea) was synthsized by various mesoporous silica. Finally, the mesoporous transition metal structure synthesized using CMK structure. Nitrogen adsorption/ desorption, SEM, low angle X-ray diffraction were carried for analysis of each sample. The optimum synthesis condition of mesoporous transition metal structure derived from characteristic analysis. The SBA-15 is best precursor for synthesis of mesoporous transition metal structure. The surface area of copper mesorporous structure from CMK(SBA-15) is $225m^2/g$, pore diameter is 2.91nm by BET analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07b
• /
• pp.1113-1115
• /
• 2002

Mesoporous silica, MCM-41, was synthesized by sol-gel method. The organic structure-directing agent must be removed to make the desired proes. To achieve this, alternative calcination method using microwave oven was adapted to this removal stage. Microwave calcination was shown to provide a novel, rapid and inexpensive method of praparing nanoporous material. It was studied how the porous structure, surface area and pore size distribution were changes under microwave calcination.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.11
• /
• pp.1985-1992
• /
• 2007

Ordered mesoporous silica (MCM-41) materials with different textural properties were prepared using alkyl (dodecyl, cetyl, eicosane) trimethyl ammonium bromide (DTAB, CTAB, ETAB, respectively) as structure directing surfactants, functionalized with amine groups and used as adsorbent for the toxic metal ions, Cr (VI), As (V), Pb (II) and Hg (II). Amino functionalization of mesoporous MCM-41 was achieved by cocondensation of N-[3-(trimethoxysilyl)-propyl] aniline with tetraethyl orthosilicate. Adsorption isotherm and adsorption capacity of the amine functionalized materials for Cr (VI), As (V), Pb (II) and Hg (II) ions were followed by inductively coupled plasma mass spectrometry (ICP-MS). Results demonstrate that amine functionalized MCM-41 prepared with ETAB showed higher adsorption capacity for Cr (VI), As (V), Pb (II) and Hg (II) ions in comparison to MCM-41 prepared with CTAB and DTAB. The higher adsorption capacity for MCM-41(ETAB) was correlated with amine content in the material (determined by CHN analysis) and relative decrease in pore volume and pore diameter. X-ray diffraction (XRD) analysis, nitrogen adsorptiondesorption measurements and Fourier Transform infrared spectrometry (FTIR) were used to follow the changes in the textural parameters and surface properties of the mesoporous materials as a result of amine functionalization to correlate with the adsorption characteristics. The adsorption process was found to depend on the pH of the medium.

• Journal of the Korean Applied Science and Technology
• /
• v.21 no.4
• /
• pp.345-351
• /
• 2004

Highly ordered pure-silica MCM-41 materials possessing well-defined morphology have been successfully prepared with surfactant used as a template. The fabrication of mesoporous silica has received considerable attention due to the need to develop more efficient materials' for catalysis, separations, and chemical sensing. The surface modified MCM-41 was used as anadsorbent for biomolecules. Silica-supported organic groups and DNA adsorption on surface modified MCM-41 were investigated by FT-IR and UV-Vis spectrometer, respectively. The use of MCM-41 as the modification of electrode surfaces were investigated electrochemical properties of metal mediators with biomolecules. The modified ITO electrodes increased peak currents for a redox process of $[Ru(bpy)_3]^{2+}$ relative to the bare electrode. The electrochemical detection of DNA by cyclic voltammetry when the current is saturated in the presence of the mediator appeared more sensitive due to a higher catalytic current on the MCM-41 supported electrodes modified by carboxylic acid functional groups. The carboxyl or amine groups on the surface of MCM-41 interact and react with the $-NH_2$ groups of guanine and backbone, respectively. Highly ordered mesoporous materials with organic groups could find applications as DNA sensors.

• Journal of the Korean Chemical Society
• /
• v.55 no.3
• /
• pp.430-435
• /
• 2011

Coal fly ash of thermal power plants converted into mesoporous materials MCM-41. The synthesized material was characterized by XRD, FT-IR, SEM, and EDS techniques. The catalytic activity of prepared material was studied for the synthesis of 5-arylindene malononitriles via Knoevenagel condensation of aromatic aldehydes and malonontrile is described. The features of present method are easy handling, stability, reusability, and eco-friendliness of catalyst, high yields, short reaction time, simple experimental and work up procedure.