A method for synchronously preparing a profiled inorganic nanofiber membrane

Abstract

The present application relates to a kind of methods for preparing heteromorphic inorganic nanofiber membrane synchronously.The method is first to dissolve polymer spinning aid, acidic chloride precursor, silica precursor in volatile solvent, using electrospinning technology to carry out spinning solution and form film, then the hybrid nanofiber membrane containing polymer spinning aid, acidic chloride precursor and silica precursor is calcined at high temperature, and heteromorphic inorganic nanofiber membrane is obtained.Compared with the nanofiber membrane material prepared by the existing process technology, the heteromorphic nanofiber membrane in the present application shows good gas purification performance, high efficiency for particulate matter separation, low filtration resistance, and provides a reference for high-efficiency low-energy air purification membrane material and other related fields.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of air purification membrane preparation, and relates to a method for synchronously preparing a special-shaped inorganic nanofiber membrane. BACKGROUND

[0002] Air purification is crucial for passive pollution control of advanced manufacturing and human health protection. The air permeability and separation performance of gas purification materials are core technical indicators related to process energy consumption and efficiency, and are also the main target direction of the development of gas purification materials. Nanofiber membranes have high specific surface area and high porosity, and have become one of the main methods for manufacturing high-efficiency air purification materials. At present, gas purification nanofiber membranes with special fiber structures, such as spiderweb-shaped nanofiber membranes (CN104562444A), effectively improve the physical interception ability of particulate matter, and to some extent, realize high-efficiency air filtration. However, due to the cross-sectional shape and packing density of electrospun fibers, it is still an important challenge to simultaneously improve the air permeability and separation efficiency of the fiber membrane. SUMMARY

[0003] The application solves the problems in the prior art and provides a method for synchronously preparing a high-efficiency, low-resistance special-shaped inorganic nanofiber membrane, and the preparation process is simple. The method can be applied to air purification in a high-temperature environment.

[0004] The technical scheme of the application is as follows:

[0005] A method for synchronously preparing a special-shaped inorganic nanofiber membrane, wherein the mass ratio of a high-molecular auxiliary spinning agent, an acidic chloride precursor, a silicon oxide precursor solution and a volatile solvent is 5:(0.5-20):(0.5-100):50; rod-shaped and strip-shaped structure fibers are mixed, the rod-shaped fibers have a diameter in the range of 300-500 nm, and the strip-shaped fibers have a width in the range of 750-1640 nm and a thickness in the range of 90-110 nm, and the specific operation includes the following steps:

[0006] (1) slowly pour the high-molecular particles into a solvent, heat at 60-90 DEG C, fully stir to obtain a high-molecular auxiliary spinning agent, slowly pour the acidic chloride into the volatile solvent, fully stir to obtain an acidic chloride precursor, slowly pour the silicon oxide precursor into the solvent, fully stir to obtain a silicon oxide precursor, mix the high-molecular auxiliary spinning agent, the acidic chloride precursor and the silicon oxide precursor according to a certain proportion, uniformly stir at room temperature, and obtain a spinning solution;

[0007] (2) use electrospinning technology to spin the spinning solution at a certain temperature and humidity environment, at a certain injection speed, spinning voltage and receiving distance, and obtain composite fibers containing the high-molecular auxiliary agent, the acidic chloride precursor and the silicon oxide precursor;

[0008] (3) high-temperature calcination of the composite fiber containing the high-molecular auxiliary spinning agent, the acidic chloride precursor and the silicon oxide precursor according to a certain temperature rising procedure, to obtain the profiled inorganic fiber membrane.

[0009] The high-molecular auxiliary spinning agent in step (1) of the application includes one or more of polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, polyvinyl butyral and polyethylene glycol.

[0010] The acidic chloride precursor in step (1) of the application includes one or more of hydrogen chloride, ammonium chloride, stannous chloride, tin chloride and zinc chloride.

[0011] The silicon oxide precursor in step (1) of the application includes one or more of methyl orthosilicate and ethyl orthosilicate.

[0012] The solvent in step (1) of the application includes one or more of water, methanol, ethanol, isopropanol and n-butanol.

[0013] In the stirring and dissolving process in step (1) of the application, the temperature is room temperature to 100 ℃, and the stirring time is 0.1-10 h.

[0014] The temperature during spinning in step (2) of the application is 25-35 ℃, the humidity is 30%-45%, the advancing speed of the spinning solution is 0.5-1.5 mL / h, the spinning voltage is 10-20 kV, and the distance from the spinning needle of the electrostatic spinning machine to the receiving plate is 5-20 cm.

[0015] The medium-high temperature calcination process in step (3) of the application is: increasing the temperature from room temperature to 600-1000 ℃ at a rate of 0.5-15 ℃ / min, and then keeping the temperature for 1-2 h.

[0016] The profiled inorganic nanofiber membrane prepared by the application can be applied to the interception of PM.

[0017] Beneficial effects: the profiled inorganic nanofiber membrane prepared by the application mixes rod-shaped and strip-shaped structure fibers, and the fiber diameter, membrane pore size and other parameters can be controlled by changing the condition parameters. The prepared nanofiber membrane exhibits good air purification performance, has excellent interception performance for PM X (x=0.3, 0.5, 1.0, 2.5, 5.0, 10) and other particulate matters, has low filtration resistance, can be applied to the field of gas purification, and has broad application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a microstructure electron microscope pattern of the profiled inorganic nanofiber membrane prepared synchronously in Example 1.

[0019] Figure 2 Microstructure electron microscope images of the heteromorphic inorganic nanofiber membrane prepared synchronously in Example 2.

[0020] Figure 3 Microstructure electron microscope images of the heteromorphic inorganic nanofiber membrane prepared synchronously in Example 3.

[0021] Figure 4 Microstructure electron microscope images of the heteromorphic inorganic nanofiber membrane prepared synchronously in Example 4.

[0022] Figure 5 Microstructure electron microscope images of the heteromorphic inorganic nanofiber membrane prepared synchronously in Example 5.

[0023] Figure 6 Microstructure electron microscope images of the heteromorphic inorganic nanofiber membrane prepared synchronously in Example 6.

[0024] Figure 7 Fiber diameter distribution images of the heteromorphic inorganic nanofiber membrane prepared synchronously in Examples 1-5.

[0025] Figure 8 Pore size distribution images of the heteromorphic inorganic nanofiber membrane prepared synchronously in Examples 1-5.

[0026] Figure 9 PM filtration performance evaluation spectrum of the heteromorphic inorganic nanofiber membrane prepared synchronously in Example 7. X (x = 0.3, 0.5, 1.0, 2.5, 5.0, 10).

[0027] Figure 10 Cyclic filtration performance evaluation spectrum of the heteromorphic inorganic nanofiber membrane prepared synchronously in Example 7. 0.3 PM. DETAILED DESCRIPTION

[0028] The present application will be described in detail below with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical solution of the present application, and detailed implementation and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0029] The present application provides a method for synchronously preparing a heteromorphic inorganic nanofiber membrane, Example 1

[0030] A method for synchronously preparing a heteromorphic inorganic nanofiber membrane, comprising the following steps:

[0031] Polymer assistant solvent preparation: 10 g of 1788 type polyvinyl alcohol particles were slowly poured into a conical flask containing 90 g of water, and after swelling for about 5 h at room temperature with stirring, the solid was completely dissolved by continuing stirring at 90 °C for 5 h. The solution was then placed in an oven at 90 °C for 12 h, and then cooled to room temperature to obtain a polyvinyl alcohol solution with a polymer to solvent mass ratio of 1:10. Acidic chloride precursor solution and silica precursor solution preparation: 1.5 g of tin tetrachloride crystals were poured into a beaker containing 4.5 g of ethanol, and stirred at room temperature for 0.5 h to obtain an acidic chloride precursor solution; 10.4 g of tetraethyl orthosilicate was poured into a beaker containing 4.45 g of deionized water, and stirred at room temperature for 2 h to obtain a silica precursor solution; 55 parts of the polymer assistant solvent, 0.5 parts of the acidic chloride precursor solution and 0.5 parts of the silica precursor solution were mixed and stirred at room temperature to obtain an electrospinning precursor solution with a mass ratio of polymer assistant solvent, acidic chloride precursor, silica precursor and solvent of 5:0.5:0.5:50; electrospinning film preparation: the electrospinning temperature was 25 °C and the humidity was 30%, the electrospinning solution was pushed at a speed of 0.5 mL / h, the electrospinning voltage was 10 kV, and the distance between the electrospinning needle and the receiving plate was 5 cm. Calcination: the obtained composite fiber was heated from room temperature to 600 °C at a rate of 0.5 °C / min, and held for 1 h.

[0032] Figure 1 The obtained heteromorphic inorganic nanofiber membrane was prepared synchronously, the average diameter of the rod-shaped fibers was 300 nm, the average width of the ribbon-shaped fibers was 750 nm, the average thickness was 100 nm, and the average pore size was 1.6 μm. Example 2

[0033] Polymer assistant preparation: 10 g of polyvinyl butyral particles were slowly poured into a conical flask containing 90 g of ethanol. After stirring at room temperature for about 5 h, the solid was completely dissolved by stirring at 90 °C for 5 h. The solution was placed in an oven at 90 °C for 12 h and then cooled to room temperature to obtain a polyvinyl butyral solution with a mass ratio of polymer to solvent of 1:10. Acidic chloride precursor solution and silica precursor solution preparation: 1.5 g of tin dichloride crystals were poured into a beaker containing 4.5 g of ethanol and stirred at room temperature for 0.5 h to obtain an acidic chloride precursor solution. 10.4 g of methyl orthosilicate was poured into a beaker containing 4.45 g of deionized water and stirred at room temperature for 2 h to obtain a silica precursor solution. 55 parts of the polymer assistant, 20 parts of the acidic chloride precursor solution and 100 parts of the silica precursor solution were mixed and stirred at room temperature to obtain an electrospinning precursor solution with a mass ratio of polymer assistant, acidic chloride precursor, silica precursor and solvent of 5:20:100:50. Electrospinning: the temperature during electrospinning was 25-35 °C and the humidity was 45%. The electrospinning solution was pushed at a speed of 1.5 mL / h, the spinning voltage was 14 kV and the distance between the spinning needle of the electrospinning machine and the receiving plate was 25 cm. Calcination: the obtained composite fiber was heated from room temperature to 1000 °C at a rate of 15 °C / min and kept for 2 h.

[0034] Figure 2 The obtained inorganic nanofiber membrane with a shape of bar and strip had an average diameter of 380 nm, an average width of 1170 nm, an average thickness of 110 nm and an average pore size of 1.7 μm. Example 3

[0035] Polymer assistant preparation: 10 g of polyvinyl butyral particles were slowly poured into a conical flask containing 90 g of n-butanol, and stirred at room temperature for about 5 h to swell, then continued to stir at 90 °C for 5 h until the solid was completely dissolved, and then placed in a 90 °C oven for 12 h, and then cooled to room temperature to obtain a polyvinyl butyral solution with a polymer to solvent mass ratio of 1:10. Acidic chloride precursor solution and silica precursor solution preparation: 1.5 g of hydrogen chloride was taken as the acidic chloride precursor solution; and 10.4 g of tetramethyl orthosilicate was poured into a beaker containing 4.45 g of deionized water, and stirred at room temperature for 2 h to obtain a silica precursor solution; 55 parts of the polymer assistant, 15 parts of the acidic chloride precursor solution and 60 parts of the silica precursor solution were mixed and stirred at room temperature to obtain an electrospinning precursor solution with a mass ratio of polymer assistant, acidic chloride precursor, silica precursor and solvent of 5:15:60:50; electrospinning film preparation: the temperature during electrospinning was 30 °C and the humidity was 35%, the electrospinning solution was pushed at a speed of 1.15 mL / h, the spinning voltage was 14 kV, and the distance between the spinning needle of the electrospinning machine and the receiving plate was 25 cm. Calcination: the obtained composite fiber was heated from room temperature to 800 °C at a rate of 10 °C / min, and kept at 800 °C for 1 h.

[0036] Figure 3 For the obtained synchronously prepared anisotropic inorganic nanofiber membrane, the average diameter of the rod-shaped fibers was 350 nm, the average width of the ribbon-shaped fibers was 1410 nm, the average thickness was 100 nm, and the average pore size was 1.73 μm. Example 4

[0037] The preparation of the acidic chloride precursor solution and the silica precursor solution was changed to: 1.5 g of tin tetrachloride crystals was poured into a beaker containing 4.5 g of ethanol, and stirred at room temperature for 0.5 h to obtain an acidic chloride precursor solution; 10.4 g of tetramethyl orthosilicate was poured into a beaker containing 4.45 g of deionized water, and stirred at room temperature for 2 h to obtain a silica precursor solution; 55 parts of the polymer assistant, 10 parts of the acidic chloride precursor solution and 70 parts of the silica precursor solution were mixed and stirred at room temperature to obtain an electrospinning precursor solution with a mass ratio of polymer assistant, acidic chloride precursor, silica precursor and solvent of 5:10:70:50; electrospinning film preparation: the temperature during electrospinning was 25 °C and the humidity was 30%, the electrospinning solution was pushed at a speed of 1 mL / h, the spinning voltage was 13 kV, and the distance between the spinning needle of the electrospinning machine and the receiving plate was 12 cm. Calcination: the obtained composite fiber was heated from room temperature to 800 °C at a rate of 5 °C / min, and kept at 800 °C for 1 h, and the other steps were completely consistent with Example 1.

[0038] Figure 4The obtained heteromorphic inorganic nanofiber membrane was prepared synchronously, the average diameter of the rod-shaped fibers was 340 nm, the average width of the ribbon-shaped fibers was 1600 nm, the average thickness was 100 nm, and the average pore size was 1.87 μm. Example 5

[0039] The preparation of the acidic chloride precursor solution and the silicon oxide precursor solution was changed as follows: 1.5 g of tin tetrachloride crystals was poured into a beaker containing 4.5 g of ethanol, and stirred at room temperature for 0.5 h to obtain the acidic chloride precursor solution; 10.4 g of tetraethyl orthosilicate was poured into a beaker containing 4.45 g of deionized water, and stirred at room temperature for 2 h to obtain the silicon oxide precursor solution; 55 parts of the polymer spinning aid, 30 parts of the acidic chloride precursor solution and 70 parts of the silicon oxide precursor solution were mixed, and stirred at room temperature to obtain an electrospinning precursor solution with a mass ratio of polymer spinning aid, acidic chloride precursor, silicon oxide precursor and solvent of 5:30:70:50; membrane preparation by electrospinning: the temperature during electrospinning was 30 ℃, the humidity was 40%, the pushing speed of the electrospinning solution was 0.95 mL / h, the spinning voltage was 12 kV, and the distance between the spinning needle of the electrospinning machine and the receiving plate was 13 cm; calcination: the obtained composite fibers were increased from room temperature to 800 ℃ at a speed of 15 ℃ / min, and kept at 800 ℃ for 1 h, and the other steps were completely consistent with those of Example 1.

[0040] Figure 5 The obtained heteromorphic inorganic nanofiber membrane was prepared synchronously, the average diameter of the rod-shaped fibers was 330 nm, the average width of the ribbon-shaped fibers was 1640 nm, the average thickness was 100 nm, and the average pore size was 3.2 μm. Example 6

[0041] The preparation of the acidic chloride precursor solution and the silicon oxide precursor solution was changed as follows: 1.5 g of tin tetrachloride crystals was poured into a beaker containing 4.5 g of ethanol, and stirred at room temperature for 0.5 h to obtain the acidic chloride precursor solution; 10.4 g of tetraethyl orthosilicate was poured into a beaker containing 4.45 g of deionized water, and stirred at room temperature for 2 h to obtain the silicon oxide precursor solution; 55 parts of the polymer spinning aid, 30 parts of the acidic chloride precursor solution and 70 parts of the silicon oxide precursor solution were mixed, and stirred at room temperature to obtain an electrospinning precursor solution with a mass ratio of polymer spinning aid, acidic chloride precursor, silicon oxide precursor and solvent of 5:30:70:50; membrane preparation by electrospinning: the temperature during electrospinning was 30 ℃, the humidity was 40%, the pushing speed of the electrospinning solution was 1 mL / h, the spinning voltage was 15 kV, and the distance between the spinning needle of the electrospinning machine and the receiving plate was 16 cm; calcination: the obtained composite fibers were increased from room temperature to 600 ℃ at a speed of 5 ℃ / min, and kept at 600 ℃ for 1 h, and the other steps were completely consistent with those of Example 1.

[0042] Figure 6 The obtained synchronization is used to prepare the shaped inorganic nanofiber membrane. Example 7

[0043] The shaped inorganic nanofiber membrane prepared in Examples 1-5 is used to filter PM X NaCl particles (x = 0.3, 0.5, 1.0, 5.0, 10) at a gas velocity of 5.33 cm / s, Figure 9 The results show that it has a PM X filtration efficiency of more than 99.96%; as Figure 10 shown, the shaped nanofiber membrane exhibits excellent PM 0.3 filtration performance at a gas velocity of 5.33 cm / s, and the shaped inorganic nanofiber membrane prepared in Example 5 has a PM 0.3 filtration efficiency that remains essentially unchanged in 20 filtration cycles, and the filtration pressure drop increases from 67 Pa to 87 Pa.

Claims

1. A method of simultaneously preparing a shaped inorganic nanofiber membrane for use in filtration of dust particulate matter, characterized by, The polymer assistant, acid chloride precursor and silicon oxide precursor are dissolved in a volatile solvent, the polymer assistant and the precursor mixed solution are spun into a film by electrospinning technology, and the heteromorphic inorganic nanofiber film is obtained by high temperature calcination, and the specific operation includes the following steps: (1) Preparation of polymer assistant: 10 g of polyvinyl alcohol particles is slowly poured into a conical flask containing 90 g of water, and stirred at room temperature for 5 h, then stirred at 90 DEG C for 5 h until the solid is completely dissolved, and then placed in a 90 DEG C oven for 12 h, and then cooled to room temperature to obtain a polyvinyl alcohol solution; Preparation of acid chloride precursor solution: 1.5 g of tin tetrachloride crystal is poured into a beaker containing 4.5 g of ethanol, and stirred at room temperature for 0.5 h to obtain an acid chloride precursor solution; Preparation of silicon oxide precursor solution: 10.4 g of methyl orthosilicate is poured into a beaker containing 4.45 g of deionized water, and stirred at room temperature for 2 h to obtain a silicon oxide precursor solution; Mixing 55 parts of polymer assistant, 10 parts of acid chloride precursor solution and 70 parts of silicon oxide precursor solution by mass ratio, and stirring at room temperature to obtain an electrospinning precursor solution; (2) The spinning solution is spun by electrospinning technology under certain temperature and humidity conditions, with a certain injection speed, spinning voltage and receiving distance, to obtain a composite fiber containing polymer assistant, acid chloride precursor and silicon oxide precursor; (3) The composite fiber containing polymer assistant, acid chloride precursor and silicon oxide precursor obtained in step (2) is calcined at a certain temperature raising program to obtain a heteromorphic inorganic fiber film, and the heteromorphic inorganic nanofiber film contains rod-shaped and strip-shaped structure fibers, the diameter of the rod-shaped fiber is 340 nm, and the width of the strip-shaped fiber is 1600 nm and the thickness is 100 nm.

2. The method of claim 1, wherein the method of simultaneous preparation of the shaped inorganic nanofiber membrane applied to filtration of dust particulate matter is characterized by: The temperature during spinning in step (2) is 25-35 DEG C, the humidity is 30%-45%, the injection speed of the spinning solution is 0.5-1.5 mL / h, the spinning voltage is 10-20 kV, and the distance between the spinning needle of the electrospinning machine and the receiving plate is 5-20 cm.

3. The method of claim 1, wherein the method of simultaneous preparation of a shaped inorganic nanofiber membrane for application in filtration of dust particulate matter is characterized by: In step (3), the high temperature calcination process is as follows: the temperature is raised from room temperature to 600-1000 DEG C at a rate of 0.5-15 DEG C / min, and then kept at this temperature for 1-2 h.

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