CN115787139A - A kind of micro-mesoporous structure SiO2 fiber material and preparation method thereof - Google Patents

Abstract

The application discloses a micro-mesoporous structure _SiO2 fiber material and a preparation method thereof, belonging to the technical field of micro-mesoporous structure materials. The preparation method of the micro-mesoporous structure _SiO2 fiber material of the present application comprises: after mixing the pore-forming agent, catalyst, tetraethyl orthosilicate and ethanol and/or water for the pre-hydrolysis time _T1 , adding the spinning aid solution for hydrolysis At time T ₂ , the spinning solution is obtained; the spinning solution is used for electrospinning, and after the spinning is completed, it is calcined to form holes, and the micro-mesoporous structure SiO ₂ fiber material is obtained. The preparation method of the present application has the advantages of simple and easy operation, high production efficiency, continuous process and low cost, and can effectively improve the micro-mesoporous structure and diameter size of the fiber material at the same time, so that the micro-mesoporous structure SiO ₂ fiber material It has a good application prospect in the field of catalyst carrier and pollutant adsorption.

Description

A kind of micro-mesoporous structure SiO2 fiber material and preparation method thereof

technical field

The application belongs to the technical field of micro-mesoporous structure materials, and in particular relates to a micro-mesoporous structure _SiO2 fiber material and a preparation method thereof.

Background technique

Micro-mesoporous structure SiO ₂ material has the characteristics of high specific surface area, adjustable pore size, rich pore structure and active sites, excellent acid corrosion resistance and thermal stability, and can be used as adsorption medium, catalyst carrier, etc. in the field of loading and adsorption middle.

At present, the preparation of micro-mesoporous SiO ₂ materials generally adopts the hydrothermal method, and usually needs to put the reaction solution into a hydrothermal kettle for hydrothermal reaction. For example, Nan Haiming and others put the aqueous solution of α-linolenic acid, γ-APS and TEOS into a hydrothermal kettle, reacted hydrothermally at a certain temperature for 48h, and cooled, filtered and dried the product overnight at a temperature of 70°C to obtain Micro-mesoporous structure SiO ₂ materials.

However, in actual production, it is found that the preparation of micro-mesoporous _SiO2 materials by hydrothermal method has the following problems: first, the production efficiency is low, the production process is discontinuous, which is not conducive to industrialization; second, the hydrothermal products are usually ultrafine powders, It is very easy to agglomerate during use; third, the size distribution uniformity of the prepared micro-mesoporous SiO ₂ powder is poor, which greatly limits the application of the micro-mesoporous SiO ₂ powder.

Contents of the invention

The purpose of this application is to provide a kind of micro-mesoporous structure SiO ₂ fiber material and preparation method thereof, aim to solve the production efficiency of micro-mesoporous SiO ₂ material prepared by hydrothermal method is low, production process is discontinuous, is unfavorable for industrialization and The product is easy to agglomerate, and the technical problem of product micro-mesopore size is not uniform.

In order to realize the above-mentioned application purpose, the technical scheme of the present application is:

The first aspect of the present application provides a method for preparing a micro-mesoporous structure SiO ₂ fiber material. The preparation method of the present application comprises the following steps:

After mixing the pore-forming agent, catalyst, tetraethyl orthosilicate, ethanol and/or water for a pre-hydrolysis time _T1 , adding a spinning aid solution for a hydrolysis time _T2 to obtain a spinning solution;

Electrospinning is carried out by using the spinning liquid, and calcined to form holes after spinning, so as to obtain a micro-mesoporous structure SiO ₂ fiber material.

In a preferred implementation of the first aspect, the pore-forming agent is cetyltrimethylammonium bromide, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer A sort of.

In a preferred implementation manner of the first aspect, the spinning aid solution is one of 10wt% polyvinylpyrrolidone aqueous solution or 12.5wt% polyvinylpyrrolidone ethanol solution.

In a preferred implementation of the first aspect, the component content of the spinning solution includes:

Spinning aid solution 35-70wt%; pore forming agent 2-15wt%; catalyst 0.01-1wt%;

Tetraethyl orthosilicate 10-20wt%; ethanol 10-35wt%; water 0-20wt%.

In a preferred implementation manner of the first aspect, the catalyst is one of hydrochloric acid and oxalic acid.

In the preferred implementation mode of the first aspect, the process parameters of the electrospinning are: the voltage is 12-25KV, the perfusion speed is 5-20μL/min, the drum speed is 20-100r/min, and the receiving distance is 10-40cm , The sliding table speed is 0-80cm/min.

In a preferred implementation manner of the first aspect, the process parameters of calcination to form pores are: heating rate of 2-10°C/min, calcination temperature of 500-650°C, and calcination time of 1-5h.

The second aspect of the embodiments of the present application also provides the SiO ₂ fiber material with micro-mesoporous structure prepared by the preparation method described in the first aspect.

Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application at least include:

In the preparation method provided by this application, the pore-forming agent, catalyst, tetraethyl orthosilicate, ethanol and water are mixed and pre-hydrolyzed, and then the spinning aid solution is added to hydrolyze to form a spinning solution, and the spinning solution is subjected to electrospinning, And by calcining the spinning product, the micro-mesoporous structure SiO ₂ fiber material can be prepared. On the one hand, the synthesis time can be shortened and the hydrothermal kettle is no longer needed. It has the advantages of high production efficiency and continuous production process. Large-scale equipment is required, the production cost is low, the operation is simple and easy, and it is conducive to industrialization; on the other hand, through the combination of pore-forming agent, catalyst, tetraethyl orthosilicate and alcohol and/or water, combined with the process parameters of electrospinning, The diameter of micro-mesoporous fibers can be effectively controlled to avoid the generation of micro-mesoporous powder materials; the third aspect combines electrospinning with pore-forming agents, catalysts, tetraethyl orthosilicate and alcohol and/or water And calcination process parameters, effectively control the micro-mesoporous structure and at the same time control the diameter of the micro-mesoporous fibers, so as to improve the uniformity of the micro-mesoporous size distribution.

The research of the examples shows that the micro-mesoporous structure _SiO2 fiber material synthesized by the present application is a multi-level structure, which is specifically manifested in the presence of a micro-mesoporous structure on the body of a single fiber, while the fibers are formed by stacking and overlapping. Micron-scale pore structure, the performance of these two structures can make the fiber material have high specific surface area and porosity, which can provide abundant active sites for applications such as environmental purification and chemical catalysis. At the same time, the micro-mesoporous structure SiO ₂ fiber material does not disintegrate in water, is resistant to acid corrosion, and is stable at high temperatures, and is easy to recycle and process in adsorption applications, and is not easy to cause secondary pollution.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings that need to be used in the description of the embodiments. Apparently, the drawings in the following description are only some embodiments described in this application, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

Fig _. 1 is the micro-mesoporous structure SiO of the embodiment of the application The schematic diagram of the preparation process of fiber material;

Fig. 2 is the micro-mesoporous structure SiO that the application embodiment ₁ prepares The SEM figure of fiber membrane CMC1;

Fig. 3 is the micro-mesoporous structure SiO that the application embodiment ₂ prepares The SEM figure of fiber membrane CMC2;

Fig. 4 is the micro-mesoporous structure SiO that the application embodiment ₃ prepares The SEM figure of fiber membrane CMC3;

Fig. 5 is the micro-mesoporous structure SiO that the application embodiment 4 prepares _The SEM figure of fiber membrane CMC4;

Fig. 6 is the micro-mesoporous structure SiO that the application embodiment 5 prepares The SEM picture of fiber membrane _CMC5 ;

Fig. 7 is an SEM image of the micro-mesoporous structure SiO ₂ fiber membrane CMC6 prepared in Example 6 of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Apparently, the described embodiments are some of the embodiments of the present application, but not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

In the following description of this embodiment, the term "and/or" is used to describe the association relationship of associated objects, which means that there may be three kinds of relationships, for example, A and/or B, which can mean: A exists alone, B exists alone and at the same time There are cases A and B. Among them, A and B can be singular or plural. The character "/" generally indicates that the contextual objects are an "or" relationship.

In the following description of this embodiment, the term "at least one" refers to one or more, and "multiple" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one (one) of a, b or c", or "at least one (one) of a, b and c" can mean: a, b, c, a-b (that is, a and b), a-c, b-c, or a-b-c, wherein a, b, and c can be single or multiple.

Those skilled in the art should understand that in the following description of the embodiments of the present application, the sequence of serial numbers does not mean the sequence of execution, some or all steps can be executed in parallel or sequentially, and the execution sequence of each process should be based on its functions and internal It is logically determined and should not constitute any limitation to the implementation process of the embodiment of the present application.

Terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a" and "the" used in the embodiments of this application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

In the first aspect, the embodiment of the present application provides a method for preparing a micro-mesoporous structure SiO ₂ fiber material. Please refer to FIG. 1, wherein, FIG. 1 shows a schematic diagram of the preparation process of the micro-mesoporous structure SiO ₂ fiber material of the present application. According to Fig. 1, the preparation method of the embodiment of the present application comprises the following steps:

S101: After mixing the pore forming agent, catalyst, tetraethyl orthosilicate, ethanol and/or water for a pre-hydrolysis time T ₁ , adding a spinning aid solution for a hydrolysis time T ₂ to obtain a spinning solution. Specifically, add the pore-forming agent, catalyst, ethanol, water and tetraethyl orthosilicate into the flask, stir evenly and carry out pre-hydrolysis for a certain time T ₁ , then add the spinning aid solution and continue the hydrolysis time T ₂ to obtain the spinning liquid. Wherein, the hydrolysis time _T1 is preferably 0-6h, and the hydrolysis time _T2 is preferably 1.5-12h.

S102: Electrospinning the spinning solution, and calcining to form pores after spinning, so as to obtain a micro-mesoporous structure SiO ₂ fiber material. Among them, the electrospinning machine used in the electrospinning process is a common equipment in the field, and the electrospinning process is a conventional operation in the field. This application only controls the process parameters of the electrospinning.

In the embodiment of the present application, the pore-forming agent, catalyst, tetraethyl orthosilicate and ethanol and/or water are mixed for a pre-hydrolysis time _T1 , and the spinning aid solution is added for hydrolysis _T2 to form a spinning solution, which is electrostatically Spinning enables the generation of micro-mesoporous structures of _SiO2 fiber materials. Among them, the pore-forming agent can automatically assemble into a structure similar to a liquid crystal template in absolute ethanol or ethanol aqueous solution. When adding tetraethylorthosilicate and performing electrospinning, the silicon material is deposited and polymerized around the liquid crystal phase to form a hexagonal structure. Organic-inorganic hybrid body, and then remove the pore-forming agent by calcination, the preparation of micro-mesoporous structure SiO ₂ fiber material can be realized; the catalyst is used to adjust the degree of hydrolysis of tetraethyl orthosilicate and finally control the fiber diameter, effectively Solve the problem that the micro-mesoporous structure SiO ₂ fiber material is easy to agglomerate; the spinning aid is used to adjust the viscosity and electrical conductivity of the spinning solution and finally control the fiber diameter, and further solve the problem that the micro-mesoporous structure SiO ₂ fiber material is easy to agglomerate . Therefore, the actual generation of the preparation method of the embodiment of the application has the following advantages:

First, it can shorten the synthesis time and eliminate the need for a hydrothermal kettle. It has the advantages of high production efficiency and continuous production process. At the same time, it does not need large-scale equipment, low production cost, and easy operation, which is conducive to industrialization;

In the second aspect, the diameter of micro-mesoporous fibers can be effectively controlled and the formation of micro-mesoporous fibers can be effectively controlled by combining pore-forming agents, catalysts, tetraethyl orthosilicate, alcohol, and water together with the process parameters of electrospinning powder material;

In the third aspect, through the combination of pore-forming agent, catalyst, tetraethyl orthosilicate, alcohol and water, combined with the process parameters of electrospinning and calcination, the micro-mesoporous structure can be effectively controlled while controlling the micro-mesoporous fiber diameter, thereby improving the uniformity of micro-mesopore size distribution.

In the embodiment of the present application, the pore-forming agent is preferably one of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and cetyltrimethylammonium bromide After being dissolved in absolute ethanol or hydroalcoholic solution, these pore formers will self-assemble into micelles and exist stably, and can be removed by calcination after spinning, which can provide stable and easy micro-mesoporous formation. Removed template structure.

In the embodiment of the present application, the spinning aid solution is one of 10wt% polyvinylpyrrolidone aqueous solution or 12.5wt% polyvinylpyrrolidone ethanol solution. Among them, the molar mass of polyvinylpyrrolidone Mw=1.3×10 ⁷ g/mol, the spinning aid solution can regulate the viscosity, surface tension, conductivity and other properties of the spinning solution, so as to realize the effective control of the fiber diameter during spinning. control.

In the embodiment of the present application, the component content of the spinning solution includes:

Spinning aid solution 35-70wt%; pore forming agent 2-15wt%; catalyst 0.01-1wt%;

Tetraethyl orthosilicate 10-20wt%; ethanol 10-35wt%; water 0-20wt%.

In the examples of this application, on the basis of compounding pore-forming agent, catalyst, tetraethyl orthosilicate, ethanol and/or water, by controlling the content ratio of each component, it is effectively ensured that tetraethyl orthosilicate and pore-forming While controlling the dissolved amount of the agent, it can effectively control the diameter of the formed fiber. Wherein, the solvent water or ethanol in the spinning aid solution and the water or ethanol contained in the spinning solution are metered separately.

In the embodiment of the present application, the catalyst is preferably one of hydrochloric acid and oxalic acid, wherein the concentration of hydrochloric acid is preferably 2mol/L, these catalysts can adjust the degree of hydrolysis of tetraethyl orthosilicate and effectively control the fiber diameter . Wherein, the solvent water in the hydrochloric acid and the water contained in the spinning solution are measured separately.

In the embodiment of the present application, the process parameters for electrospinning are: the voltage is 12-25KV, the perfusion speed is 5-20μL/min, the drum speed is 20-100r/min, the receiving distance is 10-40cm, the sliding table speed It is 0-80cm/min. By controlling these process parameters of spinning, the fiber diameter and shape can be effectively avoided, and the formation of micro-mesoporous powder materials can be avoided, thus solving the problem of micro-mesoporous structure prepared by hydrothermal method. SiO ₂ material is easy to agglomerate.

In the embodiment of the present application, the process parameters for calcination are: heating rate 2-10°C/min, calcination temperature 500-650°C, and calcination time 1-5h. By controlling the calcination process parameters, not only can the pore-forming agent be guaranteed And the spinning aid is fully removed, so that the micro-mesoporous forming effect is good, and the micro-mesoporous structure and specific surface area can be effectively controlled.

The second aspect of the embodiment of the present application also provides the micro-mesoporous structure SiO ₂ fiber material synthesized by the preparation method described in the first aspect. The preparation method based on the first aspect has the effect of controlling the diameter, shape, pore structure and specific surface area of the fiber material, so the micro-mesoporous structure _SiO2 fiber material prepared by the first aspect preparation method has better flexibility. At the same time, the specific surface area is 100-650m ² /g, the average fiber diameter is 300-700nm, and the pore size distribution on the fiber body is 1.1-7.5nm.

The technical solutions of the present invention will be further elaborated below in conjunction with specific embodiments.

Example 1

The preparation method provided in this embodiment 1 specifically includes the following steps:

S101: Add pore-forming agent, catalyst, ethanol, water and tetraethyl orthosilicate into the flask, stir evenly and carry out pre-hydrolysis time T ₁ , then add spinning aid solution for mixing and hydrolysis time T ₂ to obtain spinning solution . Wherein, the component contents and process parameters of the prepared spinning solution are as described in Table 1.

Table 1-Component content and process parameters of spinning solution

S102: Perform electrospinning on the spinning solution prepared in step S101, wherein the process parameters of electrospinning are: the voltage is 18KV, the perfusion speed is 10μL/min, the drum speed is 50r/min, the receiving distance is 20cm, and the sliding The table speed was 50 cm/min.

S103: Calcining in a muffle furnace to form pores after spinning is completed, to obtain a micro-mesoporous structure SiO ₂ fiber membrane CMC1. Among them, the process parameters of calcination into pores are: heating rate 5°C/min, holding temperature 550°C, holding time 2h.

The micro-mesoporous SiO ₂ fiber membrane CMC1 was characterized by SEM, and the results are shown in Figure 2. Among them, Fig. 2 shows the SEM image of the micro-mesoporous structure SiO ₂ fiber membrane CMC1.

According to Fig. 2, it can be seen that the distribution of fiber diameter is wide, and the average diameter is 608nm. Among them, the large number of broken fibers may be due to the high content of spinning aids and the high viscosity of the spinning solution, resulting in a large diameter of the final formed fiber, and the large number of broken fibers after forming may be due to the decrease in fiber flexibility after sintering.

Example 2

The present embodiment 2 provides micro-mesoporous structure _SiO The preparation method of fiber membrane CMC2 specifically comprises the following steps:

S101: Add pore-forming agent, catalyst, ethanol, water and tetraethyl orthosilicate into the flask, stir evenly and carry out pre-hydrolysis time T ₁ , then add spinning aid solution for mixing and hydrolysis time T ₂ to obtain spinning solution . Wherein, the component contents and process parameters of the prepared spinning solution are as described in Table 2.

Table 2-Component content and process parameters of spinning solution

S102: Electrospinning the spinning solution prepared in step S101, wherein the process parameters of electrospinning are: the voltage is 15KV, the perfusion speed is 10μL/min, the drum speed is 50r/min, the receiving distance is 20cm, and the sliding The table speed was 50 cm/min.

S103: Calcining in a muffle furnace to form pores after spinning is completed, to obtain a micro-mesoporous structure SiO ₂ fiber membrane CMC2. Among them, the process parameters of calcination into pores are: heating rate 5°C/min, holding temperature 550°C, holding time 3h.

The SEM characterization of the micro-mesoporous structure SiO ₂ fiber membrane CMC2 is shown in Figure 3. Among them, Fig. 3 shows the SEM image of micro-mesoporous structure SiO ₂ fiber membrane CMC2.

According to Figure 3, it can be seen that the fiber diameter distribution is wide, the average diameter is 500nm, and the fiber cross section tends to be flattened, which may be caused by the high water content in the spinning solution and the low voltage during spinning. The lower the voltage, the slower the jet movement, the longer the time it stays in the air, and the more serious the solvent volatilization. At the same time, the diffusion speed of the solvent inside the fiber is lower than the volatilization speed of the solvent on the fiber surface, which makes the fiber size uneven and the cross section tend to be flattened.

Example 3

Present embodiment 3 provides micro-mesoporous structure SiO The preparation method of _fibrous membrane CMC3 specifically comprises the following steps:

S101: Add pore-forming agent, catalyst, ethanol, water and tetraethyl orthosilicate into the flask, stir evenly and carry out pre-hydrolysis time T ₁ , then add spinning aid solution for mixing and hydrolysis time T ₂ to obtain spinning solution . Among them, the component content and process parameters of the prepared spinning solution are as described in Table 3.

Table 3-Component content and process parameters of spinning solution

S102: Perform electrospinning on the spinning solution prepared in step S101, wherein the process parameters of electrospinning are: the voltage is 18KV, the perfusion speed is 12μL/min, the drum speed is 50r/min, the receiving distance is 20cm, and the sliding The table speed was 50 cm/min.

S103: Calcining in a muffle furnace to form pores after spinning is completed, to obtain a micro-mesoporous structure SiO ₂ fiber membrane CMC3. Among them, the process parameters of calcination into pores are: heating rate 2°C/min, holding temperature 550°C, holding time 3h.

The SEM characterization of the micro-mesoporous structure SiO ₂ fiber membrane CMC3 is shown in Figure 4. Among them, Fig. 4 shows the SEM image of micro-mesoporous structure SiO ₂ fiber membrane CMC3.

According to Fig. 4, it can be seen that the distribution of fiber diameter is wide, and the average diameter is 463nm. This is because the greater the voltage, the greater the splitting and stretching of the fibers.

Example 4

The present embodiment 4 provides micro-mesoporous structure SiO The preparation method of _fiber membrane CMC4 specifically comprises the following steps:

S101: Add pore-forming agent, catalyst, ethanol, water and tetraethyl orthosilicate into the flask, stir evenly and carry out pre-hydrolysis time T ₁ , then add spinning aid solution for mixing and hydrolysis time T ₂ to obtain spinning solution . Wherein, the component contents and process parameters of the prepared spinning solution are as described in Table 4.

Table 4-component content and process parameters of spinning solution

S102: Electrospinning the spinning solution prepared in step S101, wherein the process parameters of electrospinning are: the voltage is 15KV, the perfusion speed is 10μL/min, the drum speed is 50r/min, the receiving distance is 20cm, and the sliding The table speed was 50 cm/min.

S103: Calcining in a muffle furnace to form pores after spinning is completed, to obtain a micro-mesoporous structure SiO ₂ fiber membrane CMC4. Among them, the process parameters of calcination into pores are: heating rate 5°C/min, holding temperature 550°C, holding time 3h.

The micro-mesoporous structure SiO ₂ fiber membrane CMC4 was characterized by SEM, and the results are shown in FIG. 5 . Among them, Fig. 5 shows the SEM image of the micro-mesoporous structure SiO ₂ fiber membrane CMC4.

According to Figure 5, it can be seen that the fiber diameter distribution is relatively uniform, and the average diameter is 336nm, which is caused by the more ethanol content and the more volatile solvent during the spinning process.

Example 5

Present embodiment 5 provides micro-mesoporous structure SiO The preparation method of _fibrous membrane CMC5 specifically comprises the following steps:

S101: Add pore-forming agent, catalyst, ethanol, water and tetraethyl orthosilicate into the flask, stir evenly and carry out pre-hydrolysis time T ₁ , then add spinning aid solution for mixing and hydrolysis time T ₂ to obtain spinning solution . Wherein, the component contents and process parameters of the prepared spinning solution are as described in Table 5.

Table 5-Component content and process parameters of spinning solution

S102: Electrospinning the spinning solution prepared in step S101, wherein the process parameters of electrospinning are: voltage 15KV, perfusion speed 15 μL/min, drum speed 50r/min, receiving distance 20cm, sliding The table speed was 50 cm/min.

S103: Calcining in a muffle furnace to form pores after spinning is completed, to obtain a micro-mesoporous structure SiO ₂ fiber membrane CMC5. Among them, the process parameters of calcination into pores are: heating rate 2°C/min, holding temperature 550°C, holding time 3h.

The micro-mesoporous SiO ₂ fiber membrane CMC5 was characterized by SEM, and the results are shown in Figure 6. Among them, Fig. 6 shows the SEM image of micro-mesoporous structure SiO ₂ fiber membrane CMC5.

According to Figure 6, it can be seen that the fiber diameter distribution is relatively uniform, and the average diameter is 318nm. Among them, the number of broken fibers is relatively large. This is because the hydrolysis time is short and the degree of hydrolysis of tetraethyl orthosilicate in the spinning solution is low. During electrospinning, the degree of fiber entanglement is low, resulting in a small diameter of the final formed fiber and poor mechanical properties of the formed fiber.

Example 6

Present embodiment 6 provides micro-mesoporous structure SiO The preparation method of _fibrous membrane CMC6 specifically comprises the following steps:

S101: Add pore-forming agent, catalyst, ethanol, water and tetraethyl orthosilicate into the flask, stir evenly and carry out pre-hydrolysis time T ₁ , then add spinning aid solution for mixing and hydrolysis time T ₂ to obtain spinning solution . Among them, the component content and process parameters of the prepared spinning solution are as described in Table 6.

Table 6-Component content and process parameters of spinning solution

S102: Electrospinning the spinning solution prepared in step S101, wherein the process parameters of electrospinning are: voltage 15KV, perfusion speed 15 μL/min, drum speed 50r/min, receiving distance 20cm, sliding The table speed was 50 cm/min.

S103: Calcining in a muffle furnace to form pores after spinning is completed, to obtain a micro-mesoporous structure SiO ₂ fiber membrane CMC5. Among them, the process parameters of calcination into pores are: heating rate 2°C/min, holding temperature 550°C, holding time 3h.

The micro-mesoporous structure SiO ₂ fiber membrane CMC6 was characterized by SEM, and the results are shown in FIG. 7 . Among them, Fig. 7 shows the SEM image of micro-mesoporous structure SiO ₂ fiber membrane CMC6.

According to Figure 7, it can be seen that the fiber formability is good, no obvious fracture phenomenon is observed, and the average diameter of the fiber is 469nm. However, the fiber diameter size distribution is broad. This is because the hydrolysis time is longer and the alcohol content in the spinning solution increases, making the volatilization of the solvent in the jet more susceptible to environmental influences during the spinning process. Makes the fiber diameter size distribution wider.

Based on the above, the present application mixes pore-forming agent, catalyst, tetraethyl orthosilicate, ethanol and water for pre-hydrolysis, then adds spinning aid solution to hydrolyze to form spinning solution, and carries out electrospinning of the spinning solution, and The spinning product is calcined to prepare and form micro-mesoporous structure SiO ₂ fiber material, realize the high efficiency, low cost and continuous industrial production of micro-mesoporous structure SiO ₂ fiber material, and improve the micro-mesoporous structure The pore structure and fiber size uniformity of the porous SiO ₂ fiber material, on the one hand, make the micro-mesoporous structure SiO ₂ fiber material have high specific surface area and porosity, and on the other hand, make the micro-mesoporous structure SiO ₂ fiber material It is rich in hydroxyl groups and has good hydrophilic performance, and it does not disintegrate in water, is resistant to acid corrosion, and is stable at high temperatures. The third aspect is that it is easy to recycle and process in adsorption applications, and it is not easy to cause secondary pollution. Therefore, the micro-mesoporous structure _SiO2 fiber material prepared in this application has broad application prospects in the fields of catalyst support and pollutant adsorption.

Various implementations in this specification are described in a progressive manner, the same or similar parts of the various implementations can be referred to each other, and each implementation focuses on the difference from other implementations.

The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the application; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still use the technology described in the foregoing embodiments The technical solution shall be modified, or some or all of the technical features shall be equivalently replaced; and these modifications or replacements shall not make the essence of the corresponding technical solution depart from the scope of the technical solution of the present application.

Claims (8)

1. a kind of micro-mesoporous structure _SiO The preparation method of fiber material is characterized in that, comprises the following steps: After mixing the pore-forming agent, catalyst, tetraethyl orthosilicate, ethanol and/or water for a pre-hydrolysis time _T1 , adding a spinning aid solution for a hydrolysis time _T2 to obtain a spinning solution; Electrospinning is carried out by using the spinning liquid, and calcined to form holes after spinning, so as to obtain a micro-mesoporous structure SiO ₂ fiber material. 2. micro-mesoporous structure SiO according to claim ₁ The preparation method of fiber material is characterized in that, described pore forming agent is hexadecyl trimethyl ammonium bromide, polyethylene oxide-polyethylene oxide One of the propylene oxide-polyethylene oxide triblock copolymers. 3. micro-mesoporous structure SiO according to claim ₁ The preparation method of fiber material is characterized in that, described spinning aid solution is the polyvinylpyrrolidone aqueous solution of 10wt% or the polyvinylpyrrolidone ethanol solution of 12.5wt% One of. 4. micro-mesoporous structure SiO according to claim ₃ The preparation method of fiber material is characterized in that, the component content of described spinning solution comprises: Spinning aid solution 35-70wt%; pore forming agent 2-15wt%; catalyst 0.01-1wt%; Tetraethyl orthosilicate 10-20wt%; ethanol 10-35wt%; water 0-20wt%. 5. micro-mesoporous structure SiO according to claim ₁ The preparation method of fiber material is characterized in that, described catalyst is a kind of in hydrochloric acid and oxalic acid. 6. The preparation method of micro-mesoporous structure _SiO2 fiber material according to claim 1, characterized in that, the process parameters of the electrospinning are: the voltage is 12-25KV, and the perfusion speed is 5-20μL/min , The drum speed is 20-100r/min, the receiving distance is 10-40cm, and the sliding table speed is 0-80cm/min. 7. The preparation method of micro-mesoporous structure _SiO2 fiber material according to claim 1, characterized in that, the process parameters of the pore formation by calcination are: heating rate 2-10°C/min, calcination temperature 500- 650°C, the calcination time is 1-5h. 8. A _SiO2 fiber material with a micro-mesoporous structure prepared according to any one of the preparation methods of claims 1-7.

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