Selective sorptive removal of Methyl Red from individual and binary component solutions by mesoporous organosilicas of MCM-41 type.

Organosilicas with chemically immobilized 3-aminopropyl and Methyl Red-containing surface groups were prepared by sol-gel condensation of tetraethyl orthosilicate and (3-aminopropyl)triethoxysilane in the presence of dye as part of the mixed micelles or dye-containing silane as silica source. The hexagonally arranged mesoporous structure of synthesized materials was confirmed by low-temperature nitrogen adsorption-desorption, x-ray diffraction, and TEM studies. Chemical composition of MCM-41-type organosilicas was established by FT-IR spectroscopy and chemical analysis of surface layer.

Structural Variety and Adsorptive Properties of Mesoporous Silicas with Immobilized Oligosaccharide Groups.

In this research, we report on the synthesis of mesoporous silicas with various quantities of immobilized oligosaccharide groups and different pore ordering degree. The hydrothermal co-condensation of tetraethyl orthosilicate and β-cyclodextrin-containing organosilane in the presence of cetyltrimethylammonium bromide template was employed. The purpose of this investigation was to show the opportunity of increasing β-cyclodextrin content in silica matrix by changing the molar ratio of initial reagents during organosilane synthesis and to determine whether the enhancing of immobilized groups on the surface influences on model aromatic compound adsorption from water.

Sol-Gel Synthesis of Ordered β-Cyclodextrin-Containing Silicas.

New approaches for β-cyclodextrin-containing silicas synthesis were demonstrated. Materials with hexagonally ordered mesoporous structure were prepared by postsynthesis grafting and by co-condensation methods. β-Cyclodextrin activated by a N,N'-carbonyldiimidazole was employed for postsynthesis treatment of 3-aminopropyl-modified MCM-41 support as well as for sol-gel synthesis with β-cyclodextrin-containing organosilane and tetraethyl orthosilicate participation in the presence of cetyltrimethylammonium bromide.

Synthesis, characterization and sorption properties of silica modified with some derivatives of β-cyclodextrin.

Nanoporous β-cyclodextrin-containing silicas which differ by functional substituents of wide edge of attached cyclic oligosaccharide molecules (alcohol, bromoacetyl, thiosemicarbazidoacetyl groups) have been synthesized. The structure and chemical composition of the surface, porosity of obtained materials, their chemical and thermal stability have been characterized by scanning electron microscopy, IR spectroscopy, thermogravimetry, nitrogen ad-desorption, elemental and chemical analyses of solid surface. Sorption of trace amounts of cadmium (II) in the presence of ten- and hundred-fold excess of hardness salts by synthesized organosilicas has been studied.

Designing of the centers for adsorption of bile acids on a silica surface.

Silicas chemically modified with attached aminopropyl, imidazolyl, and trimethylsilyl groups, with adsorptive and coordinative grafted hemin were synthesized. Adsorption of some bile acids on the surface of hydroxylated silica, synthesized siliceous adsorbents and cholestyramine has been studied. It was found that the main contribution to the total adsorption is caused by electrostatic attraction between anions of bile acids and positively charged sites of the surface of modified silica and also by dispersion interactions between steroid skeleton of bile acids and functional groups of modified silicon dioxides.

Supramolecular structures on silica surfaces and their adsorptive properties.

The study of adsorptive and chemical immobilization of beta-cyclodextrin on a surface of hydroxylated silicas with various porous structure is described. Using IR spectroscopy, thermal gravimetrical analysis with a programmed heating, and chemical analysis of the silica surface, it is shown that the process of adsorption-desorption of beta-cyclodextrin depends on the porous structure of the silica. The reaction of esterification was used for chemical grafting of beta-cyclodextrin on the surface of hydroxylated silicas.

Synthesis and properties of supramolecular systems based on silica.

The synthesis of mono-tosyl-beta-cyclodextrin (Ts-beta-CD) and its attachment to the surface of aminopropylsilica are reported. The resulting material was characterized by IR spectroscopy, elemental analysis, and quantitative evaluation of the surface compounds. The maximum amount of beta-cyclodextrin (beta-CD) grafted on the surface of silica was 60% of the computer-calculated value.

Study of interaction of poly(1-vinyl-2-pyrrolidone) with a surface of highly dispersed amorphous silica.

Interaction of poly(1-vinyl-2-pyrrolidone) with the surface of highly dispersed silica and character of its thermal destruction were investigated by means of ad-desorption measurement, vibration and electron spectroscopy, and thermal gravimetric analysis with programmed heating. The correlation between the character of polymer keeping on the surface of silicon dioxide and its thermal decomposition was established.