The present work reports results of systematic study of mesoporous materials based on silica gels with incorporated heteropolyacids. These materials have unique catalytic and adsorption properties due to presence of strong acidic sites on their surfaces. In particular, they might be used for adsorption of ions of radioactive isotope <sup>137</sup>Cs from contaminated soils and waters. The materials were synthesized by co-condensation of tetraethoxysilane (TEOS) with phosphotungstic or phosphomolybdic acids using sol-gel technique. Reactions were carried out in acidic media in ethanol/water solution. The following surfactants were used as templates: sodium dodecylsulfate, dodecylamine, trimethylstearylammonium chloride, and Pluronic P123. The products were obtained at various pH, ratios TEOS/heteropolyacid, temperatures, reaction and aging times. Effects of various reaction conditions on the yields and structural characteristics of the products were determined. All samples were amorphous with BET surface areas in the range of 400-1100 m<sup>2</sup>/g. Incorporation of heteropolyacids into silica gel slightly reduced BET surface areas as compared with pure silica gels. The best porous characteristics were achieved at the use of Pluronic P123, which was chosen for further studies. Adsorption properties of the materials and accessibility of adsorption sites were compared in selective adsorption of cesium ions from aqueous solution. Obtained results can be used in development of highly acidic porous catalysts and adsorbents.

Sol-gel synthesis of modified silica gels containing incorporated heteropolyacids

251st National Meeting (2016)

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