JPH02311329A - Porous glass and its preparation - Google Patents

Abstract

PURPOSE:To provide porous glass having a good alkali resistance and a large pore volume, most of which is originated from pores having pore radii of >=100Angstrom , by comprising a specific composition having a suitable content of TiO2 in the SiO2-TiO2 porous glass. CONSTITUTION:The porous glass has a composition comprising (a) 5 to 20wt.% of TiO2, (b) 3 to 20wt.% of an alkali(ne) earth metal oxide, (c) SiO2 of the remaining amount excluding the components (a), (b) and (d) and (d) <=10wt.% of a component other than the abovementioned components, and further has a pore volume of >=0.2ml/g, the pores having pore radii of 100 to 10000Angstrom . The porous glass can be prepared by mixing porous glass comprising SiO2 and TiO2 with an aqueous solution of an alkali(ne) earth metal compound, heating the homogeneous mixture at approximately 500 to 900 deg.C to form glass, and subsequently eluting water-soluble components.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a porous glass and a method for producing the same.

[Problems to be Solved by the Prior Art and the Invention 1 Porous glass with very well-aligned pores has good substance separation performance. Therefore, it is attracting attention as a chemical industry for gas separation, reverse osmosis, ultrafiltration, blood purification, etc., as a medical separation membrane material, as a carrier for enzymes and catalysts, as a packing material for chromatography, etc.

However, since the skeleton of conventional porous glass is mainly composed of 5iOz, when used in an aqueous solution, it dissolves little by little and the pore diameter expands. In addition, it had serious drawbacks in durability, such as dissolving in an alkaline solution in a short time.

Therefore, 5iO2-ZrO2-based porous glass (JP-A-62-202839 and Showa 61 Proceedings of the Ceramics Association Annual Meeting P, 493-494) are known.

However, it is known that in this method, the amount of zirconia that enters the glass framework is small compared to the amount of norconia used.

In addition, in the 5iO2-ZrO21A porous glass obtained by this method, zirconia is not present in the glass skeleton but in the pores of the glass skeleton in a considerable amount as zirconia dels, so zirconia dels must be eluted with a strong acid. , porous glass cannot be obtained.

Further, titanate porous glass is known as the 5i02 T;
No. 854, No. 60-239343). According to this method, titanate porous glass with a high titania content can be obtained and also has good alkali resistance. however,
Because the titania content is too high, it is a porous glass in which titania is crystallized, and the average pore radius is 30.
terialsScience, 2 East, 4309-43
16 (1985). ) = 4 = The present invention has good alkali resistance and large pore volume, most of which have a pore radius of 100 Å or more, by containing an appropriate amount of titania in the glass composition. The object of the present invention is to provide a porous glass derived from pores and a method for producing the same.

[Means for Solving the Problems] According to the present invention, there is provided a porous glass containing silica, titania, and an alkali metal and/or alkaline earth metal oxide as essential components, which has high alkali resistance and It is possible to easily obtain a material in which the total volume of pores with a pore radius in the range of 100 A to 10,000 A is 9.2+nl/g or more. □To explain the present invention in more detail, the porous glass according to the present invention has a pore radius of 100 to
It has a pore volume of 0,2+nl/H or more in the range of 10,000 people, usually 0,'5 ml/g or more. This pore volume can be determined by the manufacturing method, and it is possible to provide the optimum pore volume depending on the application. For example, it is easy to provide a material with a pore volume of 1.0 ml/g or more; We can also provide quality glass.

In the porous glass according to the present invention, the volume occupied by pores with a radius of less than 100 pores is small. Usually radius 20~10,
80% or more, preferably 90% or more of the total volume occupied by pores with a diameter of 10,000 Å is present in a radius of 100”-10,000 Å. In a preferred embodiment of the present invention, pores with a radius of 20 to 10,000 Å are present in a radius of 100” to 10,000 Å. Of the total volume occupied by pores, 60% or more, preferably 70% or more, have a radius of 500 to 5.000.
It exists in the part of 000 people. That is, the ratio of the pore volume occupied by the medium pore radius is extremely large.

In the porous glass according to the present invention, there are pores with a radius of more than 10,000 Å, but the proportion thereof is not so large. And part of what is measured as the pore volume of the part with radius larger than 10,000 Å is
This is thought to originate from the gaps between particles rather than from the pores of the particles.

The composition of the porous glass according to the present invention is 5 to 30% by weight of titania, 3.520% by weight of alkali metal and/or alkaline earth metal oxide, and the remainder is essentially silica. . However, titania, alkali metals and/or
Alternatively, components other than the alkaline earth metal oxide and silica are not excluded at all, and in some cases, components other than the above may be included in an amount of 10% by weight or less. The preferred composition of the porous glass according to the present invention is titania 10-30
The percentage by weight of alkali metal and/or alkaline earth metal oxides 3. is also 15% by weight.

The porous glass according to the present invention can be produced by mixing a porous gel made of silica and titania with an aqueous solution of an alkali metal and/or alkaline earth metal compound. to a homogeneous mixture consisting of 500 to 900
It can be manufactured by heating to ℃ and vitrifying it. When components other than silica, titania, and alkali metal and/or alkaline earth metal oxides are to be contained in the porous glass, it is preferable to contain them in advance in the porous del.

To obtain a porous gel, first, furkyl silicate is added to a solution of a lower alcohol such as methanol or ethanol with a small amount of water and an acid such as hydrochloric acid, and hydrolysis and synthesis are performed to form a partial condensate. do. Titanium alkoxide is added to this and heated to obtain a precursor. A porous del is obtained by dropping the organic solution of the precursor into water to form droplets, and then adding ammonia to the water in which the droplets are suspended to gel the droplets. The pore volume of the porous gel is preferably 0.5+nl/g or more.

If a porous gel with a pore volume smaller than this is used, the pore volume of the finally produced porous glass may become too small. (The pore volume of a porous gel is calculated by drying the porous gel at 100°C and then injecting it in the air at 2°C/in.
Refers to the volume occupied by pores with a radius of 2 O-u20,000 for those heated at 700'C* and held at this temperature for 5 hours).

Note that porous gels are not limited to those made from the above-mentioned furkyl silicate and titanium alkoxide, but may also be obtained by a coprecipitation method from titanium tetrachloride and silicon tetrachloride, titanium sulfate, titanyl sulfate, etc., and sodium silicon. It is also possible to use a silica-titania co-precipitated gel. In addition, if you want to include components other than alumina, boron oxide, other silica, titania, and alkali metal and/or alkaline earth metal oxides in the final porous glass, porous gel can be manufactured. It is preferable to add an aluminum compound or a boron compound during the process to uniformly contain alumina or boron oxide in the porous gel. For example, when an aluminum alkoxide is used in combination with a partial condensate of an alkyl silicate and a titanium alkoxide, a porous delta of silica-titania-alumina can be obtained. Although the porous gel can be mixed with the next alkali metal and/or alkaline earth metal compound while still containing water, it is usually dried to remove the water and organic solvent it contains. Preferably, the mixture is mixed. The degree of drying is arbitrary, as long as the aqueous solution of the alkali metal and/or alkaline earth metal compound can quickly penetrate into the porous gel. If desired, the porous gel may be fired prior to mixing with the alkali metal and/or alkaline earth metal compound. Note that the porous gel may have any shape, such as a plate shape or a microsphere shape.

As the alkali metal compound or alkaline earth metal compound to be mixed with the porous gel, ordinary compounds such as inorganic salts, hydroxides, or organic salts of alkali metals or alkaline earth metals can be used. Inorganic salts of alkali metals and alkaline earth metals include LiCl, NaCL, KCI
, B a Cl □, Ca Cl 2 and other halogen compounds, N a 2 CO2, K2 CO2, B a COy
Carbonates such as nitrates, nitrates, sulfates, etc. can be used. Further, as the organic salt of the alkali metal or alkaline earth metal, carboxylates such as acetates, or alkoxides can be used.

The amount of alkali metal compound and alkaline earth metal compound used is 0.0101 per 1 g of dry porous gel.
-5l0 preferably o, osg-XJsg and 2.

Even if the amount used is greater than this, the following reaction will proceed in the same way; if the amount is less than this range, the effect may not be sufficient or only a portion of the gel will become porous vitrified.

In order to uniformly disperse the alkali metal and/or alkaline earth metal compound in the porous gel, mixing the porous gel with the alkali metal and/or alkaline earth metal compound involves adding the former to the latter as an aqueous solution in order to uniformly disperse the alkali metal and/or alkaline earth metal compound in the porous gel. This is done by dipping. If both are mixed in a solid state, it is difficult to obtain a product that is uniformly vitrified to the inside in the next heating step.

The porous gel impregnated with an alkali metal and/or alkaline earth metal compound is suitably dried and then heated to vitrify it.

Heating conditions vary depending on the quantitative ratio of the porous gel to the alkali metal compound or alkaline earth metal compound, the type of the alkali metal compound or alkaline earth metal compound, the desired product, etc., but are generally 500°C. The above heating is carried out at a heating temperature of 900° C. or less and a heating time of 1 hour to 24 hours. If the heating temperature is low or the heating time is short,
If the growth of the glass particles is insufficient and, on the other hand, the heating temperature is too high or the heating time is too long, the glass will have almost no porosity.

The heating atmosphere can be either in the presence of air or in an inert gas atmosphere.

In this heat treatment step, the alkali metal and/or alkaline earth metal compound reacts with the silica and titania of the porous gel to form a glass made of silica, titania, and alkali metal and/or alkaline earth metal oxide. Fine particles are generated.

After the heat treatment, it is washed with water to remove excess alkali metal compounds, alkaline earth metal compounds, and water-soluble compounds produced by the reaction. Washing with water may be carried out with water containing acid or alkali, if desired.

After washing with water, the product is dried at around 100°C.

Furthermore, if it is necessary to remove adsorbed water from the porous glass product, the adsorbed water may be desorbed by heating to 200° C. or higher.

When the morphology of the porous glass of the present invention is observed using a scanning electron microscope, it is confirmed that the glass-like fine particles have a substantially uniform diameter and are connected to each other as if they were fused. This shape is similar to the porous glass obtained by the conventional phase separation method, but the gel interposed between the glass skeletons, which is seen in the porous glass obtained by the conventional phase separation method, is not observed.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

In the examples, pore distribution and volume were determined using a mercury intrusion poronmeter (Autobore 9200 manufactured by Micrometrics).
It was measured with The measurement range of pores is 20 Å or more in radius.

The specific surface area was calculated by the BET method using the nitrogen adsorption method. The model used for the measurement was Carlo Erba's Two Buttomatic 18.
It is 00.

Example 1 [Manufacture of raw material gel] 250 g of tetraethylorthosilicate (manufactured by Tokyo Kasei)
, 68.2 g of ethanol, 5.4 g of water and 0.2 g of ethanol. IN-
6 by adding a solution consisting of 9.4 g of MCI ethanol solution.
A partial condensate of tetraethylorthosilicate was prepared by heating at 0 °C for 30 min (H20/Si(OE t
), molar ratio 0.25). To this, titanium ethoxide 26
．． 2g, ethanol 10g and Improper Tools 10t
After adding r to make a homogeneous solution, the temperature of the oil bath was 12
After heating at 0° C. for 1.5 hours, almost no volatile components were distilled out.

Next, the temperature of the oil bath was increased to 150°C to further distill out the volatile liquid, and the precursor solution was 238.9. I got it.

Add 22.5 ml of t-7 mil alcohol to this precursor 451.
and 6.01 g of cyclohexane to make a homogeneous solution d.

This solution was added dropwise to an aqueous solution consisting of 433.9 g of water, 13.5 g of ethanol, and 3.4 g of Tween 20 (polyoxyethylene sorbitan monolaurate) to form droplets, and then 36% of 28% ammonia water was added while stirring.
An ammonia solution consisting of 1 and 22.5 nl of water was added little by little to form a gel. Stirring was continued for an additional 2 hours, and then the product was allowed to settle overnight. After removing the supernatant by decantation, ethanol was added and the mixture was stirred for 30 minutes, followed by decantation again for washing. The solution was further separated from the solution by filtration, and then dried in a dryer at 100°C for 3 hours. This dried gel was microparticles with a particle size of about 10 μm to 400 μm. In addition, when this del was fired at 700°C for 5 hours, the content was 84% by weight 5io2 16% by weight T i O
The composition of No. 2 had a total pore volume of 3.10 cc/g, and showed a broad pore distribution in the range of about 50 to 20,000 pores.

[Manufacture of Porous Glass] To 1.5 g of the dried del produced as described above, 8.07 [1] of a 15% by weight aqueous solution of barium chloride was added, and the aqueous solution was adsorbed onto the gel. After drying this at 110°C for 5 hours,
The temperature was raised to C at 2° C./min, and the mixture was fired in air at this temperature for 5 hours. After cooling to room temperature, it was poured into 250+nl of water and stirred for 3 hours. The supernatant liquid was removed by decanting, 250 ml of water was added again, heated at 90"C for 3 hours, and then allowed to cool. The supernatant liquid was removed by decanting, then 11 water was added, stirred, and then filtered. Collect the product, 11
It was dried at 0° C. for 5 hours (yield: 1.37 g).

As a result of chemical analysis, the composition of the obtained product was found to be silica 79
．． 5% by weight, titania 12.6% by weight, barium oxide 7
．． It was 9% by weight. The specific surface area was 12If12/g, and the peak position of the pore distribution was at a pore radius of 2.000 mm. Pore volume is radius 20・s 10,000
The human range is 1.41b+l/g, radius 100~1
0,000Å is 1.40vll/gz radius 500
~5,000 people had 1.20 m1/g. In addition, the pore volume in the radius range of 20 to 80,000 people is 1.
It was 97+al/g.

Example 2 A mixture of dry gel and barium chloride was heated at 760°C for 5 minutes.
A porous glass was produced in the same manner as in Example 1, except that the glass was fired for a certain period of time. The composition of the product is 74.5% by weight of silica
, titania 13.5% by weight, and barium oxide 12.0% by weight. The specific surface area was 34LI12/g, and the peak position of the pore distribution was at a pore radius of 1947 mm. The pore volume is 1.851/g for those with a radius of 20-1, 10,000 people, 1,69 m17g for those with a radius of 100-10,000 people, and 50.0-5,000 pores for a radius of 1.851/g.
0 people had i,31+el/g. In addition, the pore volume in a radius of 2O-u80,000 people is 2.51/
It was g.

Example 3 For 1.0 g of dry gel, 5.8 ml of a 5% by weight aqueous solution of sodium chloride (0.29.
) and baked at 700°C for 5 hours.
Porous glass was produced in the same manner as 6. The product has a radius of 2
Pore volume in the range of O-u80,000 is 2.91m1
/g, the peak position of the pore distribution was at a pore radius of 1487 mm, and the specific surface area was 211I12/g. The pore distribution curve is shown in Figure 2, and the pore volume of a person with a radius of 20 x 10,000 is 2.05 x 1/g and a radius of 100 - 910,00.
The pore volume of 0 Å is 1.99 x 1/g, the radius is 500~5,
000 people was 1.73 m1/g. The composition is approximately 83% by weight of silica and approximately 13% by weight of titania.
, oxidation) IJium is estimated to be about 4% by weight.

Example 4 1. Except for firing at 730°C for 5 hours. A porous glass was produced in the same manner as in Example 3. The product has a radius of 20~
Pore volume in the range of 80,000 people is 2.10+el/g
, the peak position of the pore distribution is at the pore radius of 1948 people,
The specific surface area was 10III2/g.

The pore volume in the pore radius range of 20 to 10,000 Å is 1.211/g, the pore volume in the pore radius 100 to 10,000 Å is 1.15 m1/g, and the pore volume in the pore radius 500 to 5,000 Å is 1.211/g. It was 0.89 ml/g.

Note that the composition is estimated to be almost the same as that of Example 3, or to have slightly more sodium oxide.

Comparative Example 1 Tetraethyl orthosilicate (manufactured by Tokyo Kasei) 500g
, 136.3 g of ethanol, 43.24 g of water and 0
．． A solution consisting of 18.7 g of 1N-HCl ethanol solution was added and heated at 60 °C for 30 minutes to prepare a partial condensate of tetraethylorthosilicate (H20/Si
(OEt)=) molar ratio 1.0, HCI/5i(OEt
)<molar ratio o, o O1). Next, under an argon atmosphere, the oil bath was heated at a temperature of 120°C for 1.5 hours to distill off volatile components, and then the oil bath temperature was raised to 150°C.
The volatile liquid was further distilled off to obtain 337.5 g of a solution containing a partial condensate of silicon alkoxide. Add 22.5 tnl of t-amyl alcohol to 45 ml of this solution.
and 7.5+nl of cyclohexane were added to make a homogeneous solution.

Add this to 433.9g of water, 13.5g of ethanol and T+
1Ieen20 (polyoxyethylene sorbitan mo/laure))) to form droplets, and then, while continuing to stir, an ammonia solution consisting of 28% ammonia water 36I111 and water 22.5ml. It was added little by little to form a gel.

Stirring was continued for a further 5 hours and then the product was precipitated overnight. After removing the supernatant liquid by decantation, ethanol was added and the mixture was stirred for 3.0 minutes, followed by re-decantation and washing. After further separation from the solution by filtration,
It was dried in a dryer at 100°C for 8 hours. 2 of these dried products
The temperature was raised to 600° C. at a rate of ° C./min, and the temperature was maintained at this temperature for 3 hours under air circulation for firing. The product is 100% S
The composition consisted of iO2. .

Comparative Example 2 To 137.0 g of tetraethylorthosilicate, 37.4 g of ethanol, 3.0 g of water, and 0.0 g of ethanol were added. Add a solution consisting of 5.24 g of 1N-HCl in ethanol, and heat at 60°C.
, for 30 minutes to prepare a partially synthesized tetraethylorthosilicate. To this, titanium ethoxide 15
0. OR, 10g of ethanol and 10g of isopropanol
After adding g to make a homogeneous solution, the oil bath temperature was 120℃.
After heating at ℃ for 1.5 hours to distill off volatile components,
The oil bath temperature was set at 150° C., and the volatile liquid was further distilled off to obtain 255.9 g of a precursor solution. 9.41111 cyclohexane was added to 37.5 ml of this precursor solution and mixed for 30 minutes.

This mixture was mixed with 531 g of water, 60 g of ethanol and Tw
een20 9. After dropping it into an aqueous solution consisting of Og to form droplets, while continuing to stir, 28% ammonia water 4
An ammonia aqueous solution of 5 tnl and 1,051 liters of water was added little by little to form a gel. - At night, the precipitated microscopic bodies were separated by decantation, ethanol was added, stirred, and allowed to stand again. The supernatant liquid was separated by decantation and then dried by an evaporator. After further drying this sample at 250°C, the temperature was raised to 600°C at a rate of 1°C/min, and the sample was fired at this temperature for 3 hours under air circulation.

Chemical analysis revealed that this fired product contained 39.8% by weight of SiO2.
The composition was 58.5% by weight TiO2.

[Alkali elution test] For each sample of Examples 1 to 4 and Comparative Examples 1 to 3,
Alkali resistance was compared by quantifying the amount of eluted silica. That is, approximately 100 mg of sample was accurately weighed, and 0. The solution was soaked in 10'0 IIll of IN aqueous sodium hydroxide solution and left at room temperature for 24 hours.The solution was then sampled and the eluted silica was quantified. Table 1 shows the ratio of eluted silica to the sample used. From Table 1, it is clear that the samples according to the present invention have a very low SiO2 elution rate and good alkali resistance.

Even when compared with the results of Comparative Example 2, which has a very high Tie2 content, it can be seen that the 5in2 elution rate is low.

Table vk1 [Effects of the Invention] The porous glass according to the present invention has good alkali resistance even though the content of titania is relatively small.

In addition, its pore distribution is relatively sharp, with a radius of 10
Most of them exist in the range of 0 to 10,000 Å, and the proportion of those with a radius of 20 to 100 people is small. Also,
Pore volume, peak position of pore distribution, etc. can also be changed significantly by selecting manufacturing conditions.

The porous glass according to the present invention can be used not only for the use of known porous glasses but also for a wider range of uses since it can be used in an alkaline aqueous solution.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the pore distribution of the porous glass obtained in Example 1. FIG. 2 is a diagram showing the pore distribution of the porous glass obtained in Example 3. In these figures, 1 indicates a pore distribution curve, and 2 indicates an integral pore volume curve. - #S3 Figure is an electron micrograph showing the particle structure of the porous glass obtained in Example 1.

Claims (6)

[Claims] (1) It has the following composition, and the pore radius is 100 to 10,
An alkali-resistant porous glass having a volume of 0.000 Å pores of 0.2 ml/g or more. (a) Titania: 5 to 30% by weight (b) Alkali metal and/or alkaline earth metal oxide: 3 to 20% by weight (c) Silica: balance excluding a, b, and d (d) Components other than the above :10% by weight or less (2) It has the following composition, and the pore radius is 100 to 10,
An alkali-resistant porous glass having a volume of 0.000 Å pores of 0.2 ml/g or more. (a) Titania: 10 to 30% by weight (b) Alkali metal and/or alkaline earth metal oxide: 3 to 15% by weight (c) Silica: balance excluding a, b, and d (d) Components other than the above :10% by weight or less (3) More than 80% of the total volume of pores with a pore radius of 20 to 10,000 Å has a pore radius of 100 to 10,000 Å
A claim characterized in that the pores of
Porous glass according to 1) or (2). (4) Claim (1) characterized in that 60% or more of the total volume of pores with a pore radius of 20 to 10,000 Å is occupied by pores with a pore radius of 500 to 5,000 Å.
The porous glass according to any one of ) to (3). (5) The porous glass according to any one of claims (1) to (4), wherein the elution rate of silica is 5% or less. (6) Mix an alkali metal and/or alkaline earth metal compound with a porous gel mainly composed of silica and titania, heat-treat the mixture at a temperature of 500 to 900°C to vitrify it, and then make it water-soluble. The method for producing porous glass according to any one of claims (1) to (5), characterized in that the components are eluted.