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Антропова, Т. В.; Tsyganova, T. A.; Roskova, G. P.; Kostyreva, I. G.; Polyakova, I. N.; Медведева, С. В.

doi:10.1023/a:1011340612491

“…The study of the properties of porous glass membranes in electrolyte solutions was started with their structural characteristics in a 0.1 M HCl solution. After a 7-day contact between membranes and solution, their structure resistance coefficients β , volume porosity W in (measured by gravimetry), and the amount of SiO 2 ( ) that passed from the pore space into a solution 1 If the last number is 120, this means that this PG was not subjected to an additional thermal treatment but was only dried at 120 ° C.…”

Section: The Effect Of Thermal Treatment On the Structural And Electrmentioning

confidence: 99%

“…

Currently, high-silica porous glasses (PGs) prepared by the acid leaching of liquated alkali borosilicate glasses are widely used in practice.The influence of the composition of original glasses and conditions of their leaching on the colloidal properties of resultant porous glass membranes was studied in [1][2][3].The goal of this work is to study the effect of thermal treatment of prepared PGs on their structural (specific surface area, structure resistance coefficient, filtration factor of a liquid, and average pore radius) and electrokinetic (membrane conductivity, ion transport numbers, and electrokinetic potential) characteristics.The objects of this study were membranes prepared from industrial alkali borosilicate glasses 8B and 8V with a two-skeleton structure, as well as from SFP glass produced by the addition of small amounts of fluorine and phosphorus to the original 8B glass. The chemical composition of original glasses characterized in the Laboratory of analytical and inorganic chemistry of the Institute of Silicate Chemistry, Russian Academy of Sciences, is presented in Table 1.

In order to unify the thermal prehistory of the studied glasses, all samples were "homogenized"; i.e., allowed to stand at a temperature about 20-30 ° C higher than that of their liquation and hardened at 550 ° C in air.

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mentioning

confidence: 99%

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The Effect of Thermal Treatment on the Structural and Electrokinetic Properties of Porous Glass Membranes

Volkova

¹

,

Ермакова

²

,

Sidorova

³

et al. 2005

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Currently, high-silica porous glasses (PGs) prepared by the acid leaching of liquated alkali borosilicate glasses are widely used in practice.The influence of the composition of original glasses and conditions of their leaching on the colloidal properties of resultant porous glass membranes was studied in [1][2][3].The goal of this work is to study the effect of thermal treatment of prepared PGs on their structural (specific surface area, structure resistance coefficient, filtration factor of a liquid, and average pore radius) and electrokinetic (membrane conductivity, ion transport numbers, and electrokinetic potential) characteristics.The objects of this study were membranes prepared from industrial alkali borosilicate glasses 8B and 8V with a two-skeleton structure, as well as from SFP glass produced by the addition of small amounts of fluorine and phosphorus to the original 8B glass. The chemical composition of original glasses characterized in the Laboratory of analytical and inorganic chemistry of the Institute of Silicate Chemistry, Russian Academy of Sciences, is presented in Table 1.In order to unify the thermal prehistory of the studied glasses, all samples were "homogenized"; i.e., allowed to stand at a temperature about 20-30 ° C higher than that of their liquation and hardened at 550 ° C in air. The duration of the thermal treatment of original alkali borosilicate glasses corresponded to the time needed to establish the equilibrium due to metastable phase separation [4][5][6][7]. Conditions of the thermal treatment of original glasses, the volume concentrations of the components in two-phase glasses, their densities (as measured by the hydrostatic weighing in water at 20 ° C) are also listed in Table 1. Volume concentrations of the components were calculated with allowance made for their mass content and glass density.To produce porous glass membranes, the samples of two-phase glasses prepared as polished discs 2 mm thick with diameters of 34-35 mm were leached in a 3 or 4 M hydrochloric acid solution at 100 ° C. The leaching time was approximately twofold longer than the time required to close the treated layers. Leached samples were washed with distilled water for 5 days, and thus obtained PGs were dried at 120 ° C for 1 h. The leaching conditions and the chemical compositions of resultant PGs (characterized in the Laboratory of analytical chemistry of the Institute of Silicate Chemistry, Russian Academy of Sciences by standard methods [4]) are listed in Table 2. A part of dried samples was used to study their structural and electrosurface characteristics, and the remainder of samples was thermally treated at T TT = 400, 600, or 750 ° C for 1 h. We also studied the structural and electrosurface characteristics of PGs subjected to thermal treatment.We clarify the designations used to mark the studied porous glass membranes with the reference to the fol-Abstract -The properties of porous glass membranes prepared by acid leaching of sodium borosilicate glasses 8B and 8V and also 8B glass containing sm...

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“…It has been established that the hydrochloric acid (HCl) concentration and the leaching treatment time leads to the transformation of the micro-and mesoporous structure of porous glasses. Recently, Kreisberg et al [5] have shown structural transformation of the porous structure and, especially, the silica particle morphologies inside the pores by varying the acid concentration from 1 to 3 M. Moreover, former studies have shown that a leaching temperature of 50°C leads to the formation of a more homogeneous glass with less silica precipitate compared to those leached at 1000°C [12].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the leaching conditions (i.e., acidic concentration, time of leaching and addition of basic solution) have also been investigated [5,6,9,[12][13][14][15][16]. It has been established that the hydrochloric acid (HCl) concentration and the leaching treatment time leads to the transformation of the micro-and mesoporous structure of porous glasses.…”

Section: Introductionmentioning

confidence: 99%