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Bismuth containing porous glasses (BPGs) were prepared on the basis of high-silica micro- and macroporous glasses and also of microporous glasses thermally treated at 750°C. The chemical composition of the glasses was determined by standard analytical methods and X-ray fluorescence analysis. Energy dispersive X-ray analysis showed that bismuth is predominantly formed at the half-thickness of the membranes. Characterization of the glass morphology was carried out by scanning electron microscopy. Their structural properties (specific surface area, volume porosity, structural resistance coefficient, average pore radius) and electrosurface ones (specific electrical conductivity, transport numbers of ions in the pore channels, electrokinetic potential) were studied in 10−4–10−1 M KNO3 solutions in a neutral pH range. The results were compared with similar properties of PG membranes not modified with bismuth(III) oxide. Porous glasses doped with bismuth oxide were found to restore their electrosurface characteristics in the neutral pH range in the concentration range of KNO3 solutions under study. [ABSTRACT FROM AUTHOR]

The results of a study of the rheological properties (shrinkage on heating, viscosity) of porous glasses (PGs) obtained as a result of through acid leaching of two-phase sodium borosilicate glass doped with small additives of P2O5 and fluoride ions, as well as bismuth-containing PGs and quartzoid glasses based on them, depending on the temperature of the heat treatment of the PG and in comparison with the characteristics of the samples obtained from sodium borosilicate glass without additives, are presented. It is found that doping glass with the indicated impurities leads to a decrease in the thermal resistance of the obtained PGs and bismuth-containing PGs. The introduction of bismuth nitrate into PG in the case of the low-temperature treatment (at 120°C) lowers the temperature for the same viscosity values of quartzoid glasses by 15–20°C, in contrast to samples without additives, as well as from higher-temperature treatment (at 650°C) PGs with additives. [ABSTRACT FROM AUTHOR]

Composite materials (CMs) doped with AgI or AgBr and Tb3+ or Sm3+ ions are synthesized based on matrices of high-silica nanoporous glass (NPGs). The structure of the CMs is studied by IR spectroscopy in the frequency range of 4000 to 400 cm–1. Bands corresponding to the Ag–O vibrations are found in the IR transmittance spectra of the CMs in the range of 604 to 592 cm–1. The presence of bands is established, which is associated with the existence of O–Ln–OH, Ln–O–Ln, Ln–O–H, and Ln–O (Ln = Tb, Sm) bonds compared with the NPG and series of materials without rare-earth ions (terbium or samarium). The peaks corresponding to the Ag2O and Sm2O3 oxides are found in the CMs at 940–936 and 640 and 640 cm–1, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Bismuth-containing composite materials are synthesized by the impregnation of matrices of thermally modified porous glass in 0.5 M water solutions of bismuth nitrate followed by the heat treatment of the bismuth-containing composite material in a wide temperature range of 50 to 870°C. The samples which differ by the regime of the thermal modification of porous glass (PG) (120, 400, and 600°C, duration 1 or 2 h) and the temperature of the heat treatment are studied by the near infrared spectroscopy. Dehydroxylation and glass surface concentration with impurity boron atoms occur with the growth of the heat treatment temperature. Bands caused by the absorption of Bi+ ions, bismuth active centers associated with silicon, and Bi4 and Bi3 bismuth dimers are found. [ABSTRACT FROM AUTHOR]