• Journal of the Korean Magnetic Resonance Society
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• v.3 no.2
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• pp.109-126
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• 1999

The location of Cu(II) exchanged into measoporous aluminosilicate MCM-41(AlMCM-41) material and its interaction with various adsorbate molecules were investigated by electron spin resonance and electron spin echo modulation spectroscopies. Cu(II) is fully coordinated to adsorbates in a wide open mesopore of AlMCM-41 for the formation of favorable complexes. It was found that in the fresh hydrated material, Cu(II) is octahedrally coordinated to six water molecules as evidenced by an isotropic room temperature ESR signal. This species is located in a cylindrical MCM-41 channel and rotates rapidly at room temperature. Evacuation at room temperature removes some of these water molecules, leaving the Cu(II) coordinated to less water molecules and anchored to oxygens in an MCM-41 channel wall. Dehydration at 450$^{\circ}C$ produces one Cu(II) species located on the internal wall of a channel, which is easily accessible to adsorbates. Adsorption of adsorbate molecules such as water, methanol, ammonia, pyridine, aniline, acetonitrile, benzene, and ethylene on a dehydrated Cu-AlMCM-41 material causes changes in the ESR spectrum of Cu(II), indicating the complex formation with these adsorbates. Cu(II) forms a complex with six molecules of methanol as evidenced by an isotropic room temperature ESR signal and ESEM analysis like upon water adsorption. Cu(II) also forms a square planar complex containing four molecules of N-containing adsorbates such as ammonia, pyridine and aniline based on resolved nitrogen superhyperfine interaction and their ESR parameters. However, Cu(II) forms a complex with six-molecules of acetonitrile based on ESR parameters. Only one molecule of benzene or ethylene is coordinated to Cu(II).

• Journal of the Korean Magnetic Resonance Society
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• v.1 no.2
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• pp.126-140
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• 1997

Mesoporous MCM-41 gallosilicate material was synthesized through shifting through shifting gallosilicate polymer equilibrium towards a MCM-41 phase by addition of acid. The location of Cu(II) exchanged into MCM-41 and its interaction with various adsorbate molecules were investigated by electron spin responance and electron spin echo modulation spectroscopies. It was found that in the fresh hydrated material, Cu(II) is octahedrally coordinated to six water molecules. This species is located in a cylindrical channel and rotates rapidly at room temperature. Evacuation at room temperature removes three of these water molecules, leaving the Cu (II) coordinated to three water molecules and anchored to oxygens in the channel wall. Dehydration at 45$0^{\circ}C$ produces one Cu (II) species located in the inner surface of a channel as evidenced by broadening of its ESR lines by oxygen. Adsorption of polar molecules such as water, methanol and ammonia on dehydrated CuNa-MCM-41 gallosilicate material causes changes in the ESR spectrum of Cu (II), indicating the complex formation with these adsorbates. Cu (II) forms a complex with six molecules of methanol as evidenced by an isotropic room temperature ESR signal and ESEM data like upon water adsorption. Cu(II) also forms a complex containing four molecules of ammonia based on resolved nitrogen superhyperfine interaction.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.2
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• pp.275-283
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• 2012

MCM-41(Mobil's Composition of Matter-41) and expanded graphite(EG) were investigated as potential adsorbents for heavy metal ions including Pb(II), Cu(II) and Ni(II) in various aqueous chemistries. MCM-41 showed shorter equilibrium times and higher adsorption capacities for all three heavy metal ions compared to expanded graphite. The adsorption of three heavy metal ions was significantly affected by the solution pH due to the competition with $H_{3}O^{+}$ at lower pH and precipitation at neutral or higher pH. Adsorptions of heavy metal ions onto MCM-41 and expanded graphite were successfully described with the pseudo-second-order model. During the competitive adsorption of three heavy metal ions, the selectivity of Pb(II) was highest and almost same selectivity was observed with Cu(II) and Ni(II) when MCM-41 was used as an adsorbent, while the expanded graphite exhibited the highest selectivity to Pb(II), followed by Ni(II) and Cu(II).

• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.291-296
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• 1999

The immobilization of APTMS(3-(2-aminoethylamino)propyltrimethoxysilane) and AAPTMS(3-(2-(2-aminoethyl)aminoethylanino)propyltrimethoxysilane) on the surface of high quality mesoporous molecular sieves MCM-41 and MCM-48 have been confirmed by F.T.-IR spectroscopy, Raman spectroscopy, 29Si solid state NMR, and a surface polarity measurement using Reichardt's dye. The formation of metal (Co(Ⅱ), Ni(Ⅱ), and Cu(Ⅱ)) complexes by immobilized aminosilanes have been investigated by photoacoustic spectroscopy(PAS). The assignment of UV-Vis. PAS bands makes it possible to identify the structure of metal complexes within mesoporous molecular sieves. Co(Ⅱ) ion may be coordinated mainly in a tetrahedral symmetry by two APTMS onto MCM-41, and in an octahedral one by two AAPTMS. Both Ni(Ⅱ) and Cu(Ⅱ) coordinated by aminosilanes within MCM-41 form possibly the octahedral complexes such as [Ni(APTMS)2(H20)2]2+, [Ni(AAPTMS)2]2+, [Cu(APTMS)2(H2O)2]2+, and [Cu(AAPTMS)(H2O)3]2+, respectively. The PAS band shapes of complexes onto MCM-48 are similar to those of corresponding MCM-41 with the variation of PAS intensity. Most of metal ion(Ⅱ) within MCM-41 and MCM-48 are coordinated by aminosilanes without the impregnation on the surface.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.737-741
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• 2005

In this study, the effect of copper content on the NO removal efficiency by Cu/MCM-41 has been investigated. MCM-41 was prepared by hydrothermal synthesis using a gel mixture of colloidal silica solution and cetyltrimethylammonium. Cu/MCM-41 was manufactured with copper content (5, 10, 20, and 40%) in Cu(II) acetylacetonate. The surface properties of MCM-41 were investigated by using pH, XRD, and FT-IR analyses. $N_2/77K$ adsorption isotherm characteristics, including the specific surface area and micropore volume were studied by BET's equation and Boer's t-plot methods. NO removal efficiency was confirmed by gas chromatography technique. From the experimental results, the MCM-41 was analyzed to have the surface functional groups of Si-OH and Si-O-Si and the characteristic diffraction lines (100), (110), (200), and (210) corresponding to a hexagonal arrangement structure. The copper content supported on MCM-41 appeared to increase the NO removal efficiency in spite of decreasing the specific surface areas or micropore volumes. Consequently, it was found that the copper content in Cu/MCM-41 played an important role in improving the NO removal efficiency, which was mainly attributed to the catalytic reactions.

• Bulletin of the Korean Chemical Society
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• v.22 no.9
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• pp.1045-1048
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• 2001