Composition, Structure, and Transport Properties of Bismuth Containing Porous Glasses in KNO 3 Solutions

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 KNO 3 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 KNO 3 solutions under study.