Porous hollow silicon oxide amorphous microsphere and preparation method thereof

Abstract

The invention discloses a porous hollow silicon oxide amorphous microsphere and a preparation method thereof, and belongs to the field of powder preparation, and the preparation method comprises the following steps: step 1, mixing tetrabutylammonium bromide and sodium carboxymethyl cellulose in water, dissolving, adding sodium metasilicate, and stirring to obtain a clear and transparent solution; step 2, dissolving diethyl oxalate in water, and performing ultrasonic stirring to obtain a uniform premixed solution; step 3, pouring the clear and transparent solution into the premixed solution, continuously carrying out ultrasonic stirring for a period of time, stopping stirring, and aging at room temperature; step 4, placing the aged mixed solution in an environment with the temperature of 80-90 DEG C to react for 24-48 hours, cooling, and performing centrifugal washing and drying to obtain white powder; and step 5, carrying out heat preservation on the white powder at 900-1100 DEG C for 2-4 hours to obtain the porous hollow silicon oxide amorphous microspheres. The sphere diameter of the porous hollow silicon oxide amorphous microsphere prepared by the preparation method disclosed by the invention is 1.1-4.9 microns.

Description

Technical Field

[0001] The invention belongs to the field of powder preparation, in particular to a porous hollow silicon oxide amorphous microsphere and a preparation method thereof. Background Art

[0002] Porous materials have a wide range of applications in heterogeneous catalysis, adsorption separation, chemical synthesis, environmental protection, biomedicine, etc. due to their special structure. Compared with traditional solid porous materials, hollow porous structure materials have richer pore and cavity structures, greater adjustment in material composition, performance and structure, especially in material diffusion and transmission. They are a new type of functional material with great application potential. Silica materials have been widely used in the above fields due to their high mechanical strength, stable physicochemical properties, non-toxicity, easy surface modification and many other advantages. As an important inorganic material, porous silica combines the advantages of hollow structure to form porous hollow silica microspheres with unique physicochemical properties such as large surface area, low density, good biocompatibility and strong surface permeability. Therefore, they have broad application prospects in drug storage and release, nanocatalysis and reaction, material adsorption and separation, new micro-nano sensors, functional cosmetics and other fields. At present, the main preparation method of porous hollow silica microspheres is mainly based on the template method, which is prepared by using silicate, soft template or hard template and aqueous solution system of hydrolysis catalyst. The silicate used in the template method is generally ethyl silicate, which has high raw material cost, low utilization rate and certain toxicity. The soft template or hard template used in the synthesis process is usually removed by roasting method, which easily leads to structural changes in the template removal process. In addition, some special template synthesis processes are complicated and expensive. Meanwhile, the template method is generally used to prepare nanometer or micro-nanometer sized materials. Although the porous hollow silicon oxide material of micrometer level can be obtained by controlling the techniques such as template and raw material dosage, the wall of the hollow sphere is often very thin, which is very easy to be damaged and has poor performance, which limits its application. Therefore, how to use economical raw materials to prepare micrometer level and hollow porous silicon microspheres with certain wall thickness by simple process is very worthy of research and attention. Summary of the invention

[0003] In order to solve the problems in the prior art, the present invention proposes a porous hollow silicon oxide amorphous microsphere and a preparation method thereof. In the present invention, sodium carboxymethyl cellulose and tetrabutylammonium bromide are dissolved in water and coordinated to form an ion micelle bundle, which has both template and guiding functions. After the raw materials are evenly mixed, diethyl oxalate is hydrolyzed to release hydrogen ions under a low-temperature hydrothermal environment, and the hydrogen ions react with sodium metasilicate to form silica gel, which continuously grows under the action of the ion micelle bundle, and at the same time, a pore structure is formed due to the branching effect of the micelle bundle, and a hollow porous structure is formed after a certain period of hydrothermal treatment, and finally the hollow porous silicon oxide amorphous microsphere is obtained by washing, drying and heat treatment.

[0004] The present invention provides a method for preparing porous hollow silicon oxide amorphous microspheres, comprising the following steps:

[0005] Step 1, after tetrabutylammonium bromide and sodium carboxymethyl cellulose are mixed and dissolved in water, sodium metasilicate is added and stirred to obtain a clear and transparent solution;

[0006] Step 2, dissolving diethyl oxalate in water and stirring with ultrasonic to obtain a uniform premixed solution;

[0007] Step 3, pour the clear and transparent solution into the premixed solution, continue ultrasonic stirring for a period of time (10 min), then stop and age at room temperature;

[0008] Step 4, placing the aged mixed solution in a temperature environment of 80-90° C. for reaction for 24-48 hours, cooling, centrifuging, washing and drying (centrifuging at a speed of 5000 r / min for 3 minutes, washing with water and ethanol alternately 3 times) to obtain a white powder;

[0009] Step 5: Keep the white powder at 900-1100° C. for 2-4 hours to obtain porous hollow silicon oxide amorphous microspheres.

[0010] Furthermore, the aging time in step 3 is 5-8 hours.

[0011] Furthermore, the total molar ratio of tetrabutylammonium bromide, sodium metasilicate, diethyl oxalate, and water in step 1 and step 2 is (2.1-3.2): (3.2-4.7): (7.1-7.7): (747-778); and the molar amounts of step 1 and step 2 are the same; the mass ratio of sodium carboxymethyl cellulose to sodium metasilicate is: (0.2-0.4):1.

[0012] The porous hollow silicon oxide amorphous microspheres prepared by the above method have a diameter of 1.1-4.9 μm.

[0013] Beneficial effects:

[0014] 1. The raw materials used in the present invention are widely available and cheap, the silicon source utilization rate is high, the process is simple, suitable for industrialization, and has broad application prospects.

[0015] 2. The present invention can obtain micron-sized porous hollow silicon oxide amorphous microspheres of different sizes, which are relatively uniform in size and structure, not agglomerated and have high purity.

[0016] 3. The present invention broadens the preparation technology and application field of silica microspheres. The prepared silica microspheres can be used as various carriers, adsorption separation and purification, information and communication and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a SEM image of the porous hollow silicon oxide amorphous microspheres prepared in Example 1;

[0018] Figure 2 The XRD pattern of porous hollow silicon oxide amorphous microspheres prepared in Example 1;

[0019] Figure 3 This is a SEM image of the porous hollow silicon oxide amorphous microspheres prepared in Example 2;

[0020] Figure 4 This is the SEM image of the porous hollow silicon oxide amorphous microspheres prepared in Example 3. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is described in detail below through embodiments, but the protection scope of the present invention is not limited to the embodiments.

[0022] Example 1

[0023] This embodiment provides a porous hollow silicon oxide amorphous microsphere and a preparation method, the raw material ratio: tetrabutylammonium bromide, sodium metasilicate, diethyl oxalate, water has a molar ratio of 2.1:3.2:7.1:747, the water is divided into two parts, and the mass ratio of sodium carboxymethyl cellulose to sodium metasilicate is 0.2:1. The preparation method is as follows:

[0024] 1. Mix tetrabutylammonium bromide and sodium carboxymethyl cellulose in a portion of water and dissolve them, then add sodium metasilicate and stir to obtain a clear and transparent solution;

[0025] 2. Dissolve diethyl oxalate in another portion of water and stir ultrasonically to obtain a uniform premixed solution;

[0026] 3. Pour the above clear and transparent solution into the premixed solution, continue ultrasonic stirring for a period of time (10 min), then stop, and age at room temperature for 5 hours;

[0027] 4. The aged mixed solution was placed in a temperature environment of 80°C for 24 hours, and after cooling, it was centrifuged and washed and dried (centrifuged at a speed of 5000 r / min for 3 minutes, and washed alternately with water and ethanol 3 times);

[0028] 5. The dried white powder was kept at 900°C for 4 hours to obtain porous hollow silicon oxide amorphous microspheres.

[0029] Figure 1 The SEM image of the porous hollow silicon oxide amorphous microspheres prepared in Example 1 shows that the prepared silicon oxide microspheres are porous hollow structures, and the average particle size of the microspheres is about 1.1 μm. Figure 1 It can be seen that the wall thickness of the microspheres is about 300 nm.

[0030] Figure 2 This is the XRD diagram of the porous hollow amorphous silicon oxide microspheres prepared in Example 1. It can be seen that the prepared silicon oxide microspheres are amorphous.

[0031] Example 2

[0032] This embodiment provides a porous hollow silicon oxide amorphous microsphere and a preparation method, the raw material ratio: tetrabutylammonium bromide, sodium metasilicate, diethyl oxalate, water has a molar ratio of 2.5:3.8:7.4:763, the water is divided into two parts, and the mass ratio of sodium carboxymethyl cellulose to sodium metasilicate is 0.3:1. The preparation method is as follows:

[0033] 1. Mix tetrabutylammonium bromide and sodium carboxymethyl cellulose in a portion of water and dissolve them, then add sodium metasilicate and stir to obtain a clear and transparent solution;

[0034] 2. Dissolve diethyl oxalate in another portion of water and stir ultrasonically to obtain a uniform premixed solution;

[0035] 3. Pour the above clear and transparent solution into the premixed solution, continue ultrasonic stirring for a period of time (10 min), then stop, and age at room temperature for 6 hours;

[0036] 4. The aged mixed solution was placed in a temperature environment of 85°C for 18 hours, and after cooling, it was centrifuged, washed and dried (centrifuged at a speed of 5000 r / min for 3 minutes, and washed alternately with water and ethanol 3 times).

[0037] 5. The dried white powder was kept at 1000°C for 3 hours to obtain porous hollow silicon oxide amorphous microspheres.

[0038] Figure 3 This is a SEM image of the porous hollow silicon oxide amorphous microspheres prepared in Example 2. It can be seen that the average particle size of the microspheres is about 2.5 μm.

[0039] Example 3

[0040] This embodiment provides a porous hollow silicon oxide amorphous microsphere and a preparation method, the raw material ratio: tetrabutylammonium bromide, sodium metasilicate, diethyl oxalate, water has a molar ratio of 3.2:4.7:7.7:778, the water is divided into two parts, and the mass ratio of sodium carboxymethyl cellulose to sodium metasilicate is 0.4:1. The preparation method is as follows:

[0041] 1. Mix tetrabutylammonium bromide and sodium carboxymethyl cellulose in a portion of water and dissolve them, then add sodium metasilicate and stir to obtain a clear and transparent solution;

[0042] 2. Dissolve diethyl oxalate in another portion of water and stir ultrasonically to obtain a uniform premixed solution;

[0043] 3. Pour the above clear and transparent solution into the premixed solution, continue ultrasonic stirring for a period of time (10 min), then stop, and age at room temperature for 8 hours;

[0044] 4. The aged mixed solution was placed in a temperature environment of 90°C for 12 hours, cooled, centrifuged, washed and dried (centrifuged at a speed of 5000 r / min for 3 minutes, and washed alternately with water and ethanol 3 times);

[0045] 5. The dried white powder was kept at 1100°C for 2 hours to obtain porous hollow silicon oxide amorphous microspheres.

[0046] Figure 4 This is a SEM image of the porous hollow silicon oxide amorphous microspheres prepared in Example 3. It can be seen that the average particle size of the microspheres is about 4.9 μm.

[0047] The hollow porous silicon oxide amorphous microspheres prepared by the method of the present invention have low raw material cost and simple process. The prepared microspheres are micron-sized hollow porous silicon microspheres with a certain wall thickness.

[0048] The particle size of the silicon oxide amorphous microspheres prepared by the present invention is related to the entire raw material system, mainly related to sodium metasilicate, sodium carboxymethyl cellulose, and tetrabutyl ammonium bromide. According to the raw material ratio range used in the present invention, porous hollow silicon oxide amorphous microspheres of 1.1-4.9 μm can be prepared. The increase in the amount of sodium carboxymethyl cellulose and tetrabutyl ammonium bromide is conducive to the growth of the microsphere size, and increasing the amount of sodium metasilicate can further promote the increase of the microsphere size. When the mass ratio is less than 0.2:1, some microspheres can be generated, but there are many particles with other morphologies.

[0049] In the present invention, the mixed solution is placed in a temperature environment of 80°C-90°C for 24-48 hours, and the reaction temperature is the optimal temperature range for the growth of microspheres. If the temperature is too low, the reaction synthesis efficiency is low and the time consumption is long; if the temperature is too high, the reaction process is too fast, secondary particles are easily generated, and energy is wasted.

[0050] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention.

Claims

1. A method for preparing porous hollow silicon oxide amorphous microspheres, characterized in that: The steps include: Step 1, after tetrabutylammonium bromide and sodium carboxymethyl cellulose are mixed and dissolved in water, sodium metasilicate is added and stirred to obtain a clear and transparent solution; Step 2, dissolving diethyl oxalate in water and stirring with ultrasonic to obtain a uniform premixed solution; Step 3, pour the clear and transparent solution into the premixed solution, stop ultrasonic stirring after a period of time, and age at room temperature; Step 4, placing the aged mixed solution in a temperature environment of 80-90° C. for reaction for 24-48 hours, cooling, centrifuging, washing and drying to obtain a white powder; Step 5: Keep the white powder at 900-1100° C. for 2-4 hours to obtain porous hollow silicon oxide amorphous microspheres.

2. The preparation method according to claim 1, characterized in that: The aging time in step 3 is 5-8 hours.

3. The preparation method according to claim 1, characterized in that: The molar ratio of tetrabutylammonium bromide, sodium metasilicate, diethyl oxalate, and water in step 1 and step 2 is (2.1-3.2): (3.2-4.7): (7.1-7.7): (747-778), and the amount of water in step 1 and step 2 is the same; The mass ratio of the sodium carboxymethyl cellulose to sodium metasilicate is: (0.2-0.4):

1.

4. Porous hollow silicon oxide amorphous microspheres prepared according to the preparation method described in any one of claims 1 to 3.

5. The porous hollow silicon oxide amorphous microspheres according to claim 4, characterized in that: The diameter of the porous hollow silicon oxide amorphous microspheres is 1.1-4.9 μm.

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