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Information × Registration Number 0211U009494, 0110U004580 , R & D reports Title Hybrid organic-inorganic nanoadsorbents - improvement of the synthesis and development of their production technology popup.stage_title Head Zub Yuriy Leonidovych, Registration Date 23-12-2011 Organization Institute of Surface Chemistry of the National Academy of Sciences of Ukraine popup.description2 Using spray drying method for two-component (considering alkoxysilanes) systems in the presence of surfactants (as template) mesoporous silica microspheres with functional surface layers can be obtained. Thus, using octadecyltrimethylammonium bromide as template, we synthesized porous microspheres (SBET = 747m2/g, d = 2,3 nm) containing phosphonic acid residues on their surfaces. It was shown, that boiling the sample in concentrated hydrochloric acid leads to complete hydrolysis of ester phosphonate groups without damaging siloxane network or porous structure. The final formula of the obtained sample: [SiO1.81 (OZ)0.38]0.91 [SiO1.35(OZ)0.29(CH2)2P(O) (OH)2]0.09 (where Z = H or Et)). According 31P solid-state NMR spectroscopy, approximately 15% of phosphonic acid groups interact with the surface silanol groups with the formation of P-O-Si bonds. It was shown, that one-step template method (template - P123) produces mesoporous silicas with surface Si(CH2)2Р(О)(OC2H5)2 functional groups. Their treatment with conc. hydrochloric acid leads to hydrolysis of ethoxy groups at phosphorus atoms, which is confirmed by IR spectroscopy. It was established, that post-synthetic treatment of the samples also increases their specific surfaces (till 600 m2/g), as well as the sorption volume, and pore diameter. Drying in vacuum at 110 ?C of samples treated with acid, gives a small number of fragments Si (CH2)2Р(О)(OH)-ОSi . However, according to TEM, the samples retain their mesoporous structure. The sorption properties of silica microspheres with surface phosphonic groups obtained by spray drying method towards of neodymium (III) and dysprosium (III) ions (in aqueous solutions) were also studied. It was shown that complexes LnL3 и LnL2+ are formed during sorption in the surface layers of mesopores. According to calculations, the "lanthanide contraction" effect causes the formation of more complexes with two ligand groups for the ion with smaller radius (Dy), and for ion with a larger radius (Nd), both complexes are formed in equal amounts in the same conditions. We demonstrated the possibility of regeneration of mesoporous microspheres using two cycles of adsorption-desorption of REE ions. Meanwhile, no significant changes in the structure of the microspheres and the composition of their surface layer are observed. Using of P123 as template, one can synthesize mesoporous SBA-15 silicas, containing thiourea groups Si(CH2)3NHC (S) NHC2H5 in the surface layers. The resulting samples are characterized by relatively high content of complexing groups and the presence of ordered spatial structure with a hexagonal lattice type. These samples have a high potential for removing heavy metal ions from aqueous solutions. According to the developed techniques implying using trifunctional silanes with fluor-containing groups in ammonium medium in the presence of tetraethoxysilane, we obtained thermally-stable xerogels with fluor-containing groups in the surface layers. The resulting silicas have well-developed porous structures (SBET = 400 - 960 m2/g, Vs = 0.66-0.93 cm3/g), and their average pore diameters depend on the length of fluorinated chains and comprise ~ 3-4 nm or ~17-20 nm. The parameters of the porous structure of these materials are determined by the ratios of reacting alkoxysilanes (ie, the content fluorinated precursor) and the nature of the functional group (the length of fluorinated chain). It was established, that synthesized hybrid materials are organophilic. The greatest affinity to hydrocarbons is exhibited by samples obtained on the basis of trifunctional silane with long fluorinated chain. Product Description popup.authors Гончарик В.П. Дударко О.А. Мельник І.В. Назарчук Г.І. Погорілий Р.П. Томіна В.В. popup.nrat_date 2020-04-02 Close