Method for preparing glass fiber membrane loaded black titanium dioxide composite membrane

Abstract

The invention relates to the technical field of composite materials, in particular to a method for preparing a glass fiber membrane loaded black titanium dioxide composite membrane. The method comprises the following steps: uniformly mixing TiO2 powder with a PVA (Polyvinyl Alcohol) solution A, granulating and drying to obtain TiO2 particles; a graphite powder layer A, a TiO2 particle layer and a graphite powder layer B are sequentially laid in the graphite crucible from bottom to top; carrying out in-furnace calcination, sample preparation and ball milling on the graphite crucible to obtain black titanium dioxide nano powder; dispersing black titanium dioxide nano powder with a PVA solution B to obtain black titanium dioxide slurry; and carrying out suction filtration on the black titanium dioxide slurry by adopting a glass fiber filter membrane to prepare the glass fiber membrane loaded black titanium dioxide composite membrane. The method provided by the invention not only overcomes the technical barrier of the black titanium dioxide thin film process, but also retains the performance index of the black titanium dioxide, simplifies the process flow, reduces the production cost, and is beneficial to reflecting the high-value application of the black titanium dioxide.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly relates to a method for preparing a glass fiber membrane-supported black titanium dioxide composite membrane. Background Art

[0002] As a typical photocatalytic semiconductor material, titanium dioxide has been widely used in the fields of environmental governance (organic pollutant degradation, air purification), new energy (photocatalytic water splitting for hydrogen production, photovoltaic electrodes), and antibacterial materials due to its non-toxicity, high chemical stability, strong oxidation ability, etc. However, the narrow bandgap width of traditional anatase titanium dioxide (~3.2 eV) results in its ability to only absorb ultraviolet light (accounting for 4% of the solar spectrum), severely restricting the practical application value of photocatalytic efficiency. To break through this limitation, researchers have developed black titanium dioxide, introducing oxygen vacancies and Ti 3+ defect states into the crystal through means such as hydrogenation reduction and doping modification, expanding its light response range to the visible-near infrared region (400 - 1200 nm) and significantly improving its solar light utilization rate. However, both the preparation method and application form of black titanium dioxide materials are relatively complex in the technical implementation process and require high equipment requirements.

[0003] Currently, compared with conventional titanium dioxide, black titanium dioxide has a significantly broadened light response range. However, it faces four major technical barriers during the film formation process: 1. Poor controllability of the defect state concentration and distribution; 2. Insufficient stability of nanoparticles and interfacial binding force; 3. High recombination rate of photo-generated carriers; 4. Low process compatibility for large-scale preparation. To overcome the above technical barriers, local optimization is often achieved by sacrificing a certain performance index of black titanium dioxide (such as reducing the defect concentration to improve stability), making it difficult to meet the comprehensive requirements for film activity, durability, and preparation economy in practical applications.

[0004] In the prior art, CN119432129A discloses a method for preparing and applying a low refractive index black titanium dioxide composite material, which discloses a method for producing a low refractive index black titanium dioxide and nano-SiO2 composite material powder using silicon powder and titanium dioxide, and coating the composite material powder into a coating solution and applying it on the glass surface, and then preparing a low refractive index black titanium dioxide composite material coated glass through drying (100 °C) and high-temperature treatment (> 450 °C). The refractive index and resistivity of the black titanium dioxide composite material are significantly reduced. However, the method for preparing the coated glass is complex, requires a large amount of raw materials, and requires two high-temperature treatments (calcination + high-temperature coating).

[0005] CN106637104A and CN106622247A respectively disclose the preparation of black titanium dioxide thin films by pulsed laser sputtering deposition method and electrophoretic deposition method, and achieve the purpose of uniform and controllable thickness of black titanium dioxide thin films. However, for the stability of black titanium dioxide thin films, black titanium dioxide spheres need to be stacked layer by layer, and the spheres are combined by fusion welding, and the problem of insufficient bonding force at the interface with the substrate remains unresolved.

[0006] CN110935449A discloses an efficient and environmentally friendly black titanium dioxide-based photocatalyst and its preparation method, which specifically discloses the preparation of co-doped black titanium dioxide; mixing the co-doped black titanium dioxide, a loading substrate, and a solvent to obtain a mixture; and stirring the mixture, impregnating for more than 12 hours, drying, and then performing heat treatment to obtain the black titanium dioxide-based photocatalyst. The light shielding effect of the disclosed carrier substrate restricts the high-value utilization of light energy by black titanium dioxide.

[0007] In summary, how to realize the high-value application of black titanium dioxide still faces technical challenges. Summary of the Invention

[0008] The present invention provides a method for preparing a glass fiber membrane-supported black titanium dioxide composite membrane, which not only overcomes the technical barriers in the process of thin film formation of black titanium dioxide, retains the performance indicators of black titanium dioxide after thin film formation, but also simplifies the process flow of the black titanium dioxide composite membrane, reduces production costs, and is conducive to realizing the high-value application of black titanium dioxide.

[0009] The method for preparing a glass fiber membrane-supported black titanium dioxide composite membrane includes the following steps:

[0010] 1) Granulation: Mixing TiO2 powder and PVA solution A, granulating, and drying to obtain TiO2 particles;

[0011] 2) Laying materials: Laying graphite powder in a graphite crucible to form a graphite powder layer A, then uniformly placing the TiO2 particles granulated in step 1) on the upper side of the graphite powder layer A to form a TiO2 particle layer, and finally laying graphite powder on the TiO2 particle layer to form a graphite powder layer B;

[0012] 3) Calcination and reduction: Calcining the graphite crucible obtained by laying materials in step 2) in a furnace, making samples, and ball milling to obtain black titanium dioxide nano-powder;

[0013] 4) Dispersion: Dispersing the black titanium dioxide nano-powder obtained by calcination and reduction in step 3) with PVA solution B to obtain a black titanium dioxide slurry;

[0014] 5) Preparation of composite film: Use a glass fiber filter membrane to perform suction filtration on the black titanium dioxide slurry dispersed in step 4) to prepare a composite film with black titanium dioxide loaded on the glass fiber membrane.

[0015] In a specific embodiment of the present invention, in step 1) granulation, the mass ratio of the TiO2 powder to the PVA solution A is (8 - 10):1; preferably, the PVA solution A is a 6wt% aqueous PVA solution.

[0016] In a specific embodiment of the present invention, in step 1) granulation, the particle size of the TiO2 particles is 3 - 5 mm; the drying is carried out at 100 - 120 °C for 2 h.

[0017] In a specific embodiment of the present invention, in step 2) laying materials, the mass ratio of the graphite powder layer A to the graphite powder layer B is (1.5 - 2):1; the mass ratio of the TiO2 particle layer to the total mass of the graphite powder layer A and the graphite powder layer B is 11:6.

[0018] In a specific embodiment of the present invention, in step 3) calcination and reduction, the temperature of the calcination is 750 - 950 °C, and the time is 1 - 2 h; the time for sample preparation is 1 min; the rotation speed of the ball milling is 300 r / min, and the time is 8 h.

[0019] In a specific embodiment of the present invention, in step 3) calcination and reduction, the particle size of the black titanium dioxide nano - powder is 50 - 100 nm, its oxygen vacancy concentration is 5 - 15wt%, and the proportion of the anatase phase is ≥80wt%.

[0020] In a specific embodiment of the present invention, in step 4) dispersion, the mass ratio of the black titanium dioxide nano - powder to the PVA solution B is 1:(0.95 - 1.05).

[0021] In a specific embodiment of the present invention, the PVA solution B is an aqueous PVA solution with a concentration of 0.5 - 5wt%.

[0022] In a specific embodiment of the present invention, in step 5) preparation of the composite film, the mass of the black titanium dioxide slurry is in a ratio of 2 g to the flat - laying area of the glass fiber filter membrane of 19.625 cm 2 ; preferably, the pore size of the glass fiber filter membrane is 5 - 10 μm.

[0023] In a specific embodiment of the present invention, in step 5) preparation of the composite film, the vacuum degree of the suction filtration is ≤0.08 MPa, and the time is 25 - 35 s.

[0024] In the method of the present invention, PVA refers to polyvinyl alcohol.

[0025] The beneficial effects of the present invention are as follows:

[0026] 1. The method for preparing the glass fiber membrane-supported black titanium dioxide composite membrane of the present invention not only simplifies the process, saves costs, but also does not produce harmful production areas, improving the production efficiency and economic benefits of the glass fiber membrane-supported black titanium dioxide composite membrane;

[0027] 2. The method of the present invention uses a glass fiber filter membrane as a carrier / substrate, solving the problem of light shielding effect of traditional carriers (such as carbon fiber), and compared with traditional carbon fiber carriers, the light energy utilization rate of black titanium dioxide can be increased by 50%;

[0028] 3. In the method of the present invention, the chemically inert substrate of the glass fiber filter membrane can inhibit the surface oxidation of black titanium dioxide nanoparticles and maintain the stable defect state of black titanium dioxide;

[0029] 4. The glass fiber membrane-supported black titanium dioxide composite membrane prepared by the method of the present invention has both filtration separation and photocatalytic degradation functions, and can simultaneously achieve pollutant interception and in-situ mineralization. It can not only be applied to the treatment of organic sewage, such as domestic sewage, organic dye wastewater, etc., but also be applied to the field of photothermal interfacial water evaporation, such as solar evaporators, steam-water condensation systems, etc., with a wider range of application scenarios;

[0030] 5. The method of the present invention makes full use of the rich titanium resources in the Panxi region, realizes the effective utilization of resources, and can be combined with glass fiber materials at the same time, applied to sewage treatment and seawater desalination, protecting the ecological environment, and providing a new path for achieving the "dual carbon goal". BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the SEM image of the black titanium dioxide nanopowder provided in Example 1 of the specific embodiment of the present invention;

[0032] Figure 2 It is the TEM image of the black titanium dioxide nanopowder provided in Example 1 of the specific embodiment of the present invention. SPECIFIC EMBODIMENTS

[0033] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments of the present invention fall within the scope protected by the present invention.

[0034] The method for preparing a glass fiber membrane-supported black titanium dioxide composite membrane includes the following steps:

[0035] 1) Granulation: Mix TiO2 powder with PVA solution A, granulate and dry to obtain TiO2 particles;

[0036] 2) Laying materials: Lay graphite powder in a graphite crucible to form graphite powder layer A, then evenly place the TiO2 particles granulated in step 1) on the upper side of graphite powder layer A to form a TiO2 particle layer, and finally lay graphite powder on the TiO2 particle layer to form graphite powder layer B;

[0037] 3) Calcination and reduction: Calcinate the graphite crucible obtained from the auxiliary materials in step 2) in the furnace, make samples and ball mill to obtain black titanium dioxide nano powder;

[0038] 4) Dispersion: Disperse the black titanium dioxide nano powder obtained from calcination and reduction in step 3) with PVA solution B to obtain black titanium dioxide slurry;

[0039] 5) Preparation of composite film: Use a glass fiber filter membrane to filter the black titanium dioxide slurry dispersed in step 4) to prepare a glass fiber membrane-supported black titanium dioxide composite film.

[0040] In some examples, in step 1) granulation, the mass ratio of TiO2 powder to PVA solution A is (8 - 10):1.

[0041] In some examples, PVA solution A is an aqueous PVA solution with a concentration of 6 wt%.

[0042] In some examples, in step 1) granulation, the particle size of TiO2 particles is 3 - 5 mm; drying is carried out at 100 - 120 °C for 2 h.

[0043] In some examples, in step 2) laying materials, the mass ratio of graphite powder layer A to graphite powder layer B is (1.5 - 2):1; the mass ratio of the TiO2 particle layer to the total mass of graphite powder layer A and graphite powder layer B is 11:6.

[0044] In some examples, in step 3) calcination and reduction, the calcination temperature is 750 - 950 °C, the time is 1 - 2 h; the sample preparation time is 1 min; the ball milling speed is 300 r / min, and the time is 8 h.

[0045] In some examples, in step 3) calcination and reduction, the particle size of the black titanium dioxide nano powder is 50 - 100 nm, its oxygen vacancy concentration is 5 - 15 wt%, and the anatase phase proportion is ≥80 wt%.

[0046] In some examples, in step 4) dispersion, the mass ratio of the black titanium dioxide nano powder to PVA solution B is 1:(0.95 - 1.05).

[0047] In some examples, PVA solution B is an aqueous PVA solution with a concentration of 0.5 - 5 wt%.

[0048] In some examples, in step 5) of preparing the composite film, the ratio of the mass of the black titanium dioxide slurry to the laying area of the glass fiber filter membrane is 2 g: 19.625 cm 2 .

[0049] In some examples, the pore size of the glass fiber filter membrane is 5-10 μm.

[0050] In some examples, in step 5) of preparing the composite film, the vacuum degree of suction filtration is ≤0.08 MPa, and the time is 25-35 s.

[0051] The following further gives examples to illustrate the present invention in detail.

[0052] Example 1

[0053] The method for preparing the glass fiber membrane-supported black titanium dioxide composite film in this example includes:

[0054] Weigh 50 g of TiO2 powder and mix it with 5 g of a 6% PVA aqueous solution, granulate to obtain TiO2 particles with a particle size of 3-5 mm, and dry for 2 h at a temperature of 120 °C;

[0055] Place the dried TiO2 particles evenly in a graphite crucible with 20 g of graphite powder laid on the bottom layer. After evenly spreading 10 g of graphite powder on the upper layer, place it in a high-temperature electric furnace and calcine at 750 °C for 2 h to obtain black titanium dioxide particles. After sample preparation and ball milling at a rotation speed of 300 r / min for 8 h, black titanium dioxide nano-powder with a particle size of 50-100 nm and an oxygen vacancy concentration of 10% is obtained;

[0056] The SEM image of the black titanium dioxide nano-powder in this example is as shown in the appendix Figure 1 shown;

[0057] The TEM image of the black titanium dioxide nano-powder in this example is as shown in the appendix Figure 2 shown;

[0058] Mix the obtained black titanium dioxide nano-powder with a 0.5% PVA aqueous solution evenly according to a mass ratio of 1:1 to make a black titanium dioxide slurry;

[0059] Select a glass fiber filter membrane with a diameter of 5 cm and a pore size of 10 μm to perform suction filtration on the black titanium dioxide slurry at 0.08 MPa for 30 s to obtain a glass fiber / black titanium dioxide composite film.

[0060] Example 2

[0061] The method for preparing the glass fiber membrane-supported black titanium dioxide composite film in this example includes:

[0062] Weigh 50 g of TiO2 powder and mix it with 5 g of a 6% PVA aqueous solution, granulate to obtain TiO2 particles with a particle size of 3 - 5 mm, and dry for 2 h at a temperature of 120 °C;

[0063] Evenly place the dried TiO2 particles in a graphite crucible with 20 g of graphite powder laid on the bottom layer. After evenly spreading 10 g of graphite powder on the upper layer, place it in a high-temperature electric furnace and calcine at 750 °C for 2 h to obtain black titanium dioxide particles. After sample preparation and ball milling at a rotation speed of 300 r / min for 8 h, obtain black titanium dioxide nano-powder with a particle size of 50 - 100 nm and an oxygen vacancy concentration of 10%;

[0064] Evenly mix the obtained black titanium dioxide nano-powder with a 1 wt% PVA aqueous solution in a mass ratio of 1:1 to prepare a black titanium dioxide slurry;

[0065] Select a glass fiber filter membrane with a diameter of 5 cm and a pore size of 10 μm, and perform suction filtration on the black titanium dioxide slurry at 0.08 MPa for 30 s to obtain a glass fiber / black titanium dioxide composite membrane.

[0066] Example 3

[0067] The method for preparing a glass fiber membrane-supported black titanium dioxide composite membrane in this example includes:

[0068] Weigh 50 g of TiO2 powder and mix it with 5 g of a 6 wt% PVA aqueous solution, granulate to obtain TiO2 particles with a particle size of 3 - 5 mm, and dry for 2 h at a temperature of 120 °C;

[0069] Evenly place the dried TiO2 particles in a graphite crucible with 20 g of graphite powder laid on the bottom layer. After evenly spreading 10 g of graphite powder on the upper layer, place it in a high-temperature electric furnace and calcine at 750 °C for 2 h to obtain black titanium dioxide particles. After sample preparation and ball milling at a rotation speed of 300 r / min for 8 h, obtain black titanium dioxide nano-powder with a particle size of 50 - 100 nm and an oxygen vacancy concentration of 10%;

[0070] Evenly mix the obtained black titanium dioxide nano-powder with a 3 wt% PVA aqueous solution in a mass ratio of 1:1 to prepare a black titanium dioxide slurry;

[0071] Select a glass fiber filter membrane with a diameter of 5 cm and a pore size of 10 μm, and perform suction filtration on the black titanium dioxide slurry at 0.08 MPa for 30 s to obtain a glass fiber / black titanium dioxide composite membrane.

[0072] Example 4

[0073] The method for preparing a glass fiber membrane-supported black titanium dioxide composite membrane in this example includes:

[0074] Weigh 50 g of TiO2 powder and mix it with 5 g of a 6 wt% PVA aqueous solution, granulate to obtain TiO2 particles with a particle size of 3 - 5 mm, and dry for 2 h at a temperature of 120 °C;

[0075] Evenly place the dried TiO2 particles in a graphite crucible with 20 g of graphite powder laid on the bottom layer. After evenly spreading 10 g of graphite powder on the upper layer, place it in a high-temperature electric furnace and calcine at 750 °C for 2 h to obtain black titanium dioxide particles. After sample preparation and ball milling at a rotation speed of 300 r / min for 8 h, black titanium dioxide nano-powder with a particle size of 50 - 100 nm and an oxygen vacancy concentration of 10% is obtained;

[0076] Evenly mix the obtained black titanium dioxide nano-powder with a 5 wt% PVA aqueous solution in a mass ratio of 1:1 to make a black titanium dioxide slurry;

[0077] Select a glass fiber filter membrane with a diameter of 5 cm and a pore size of 10 μm, and perform suction filtration on the black titanium dioxide slurry at 0.08 MPa for 30 s to obtain a glass fiber / black titanium dioxide composite membrane.

[0078] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a glass fiber membrane-loaded black titanium dioxide composite membrane, characterized in that: The following steps are involved: 1) Granulation: Mix TiO2 powder and PVA solution A, granulate and dry to obtain TiO2 particles; 2) Paving: Graphite powder is spread in a graphite crucible to form a graphite powder layer A, and then the TiO2 particles granulated in step 1) are evenly placed on the upper side of the graphite powder layer A to form a TiO2 particle layer, and finally graphite powder is spread on the TiO2 particle layer to form a graphite powder layer B; 3) Calcination reduction: calcining the graphite crucible obtained from the auxiliary materials in step 2) in a furnace, preparing samples, and ball milling to obtain black titanium dioxide nanopowder; 4) Dispersion: The black titanium dioxide nanopowder calcined and reduced in step 3) is dispersed with PVA solution B to obtain a black titanium dioxide slurry; 5) Preparation of composite membrane: The black titanium dioxide slurry dispersed in step 4) is filtered using a glass fiber filter membrane to prepare a glass fiber membrane-loaded black titanium dioxide composite membrane.

2. The method according to claim 1, characterized in that: Step 1) granulation, the mass ratio of the TiO2 powder to the PVA solution A is (8-10):1; preferably, the PVA solution A is a PVA aqueous solution with a concentration of 6wt%.

3. The method according to claim 1, characterized in that: Step 1) granulation, the particle size of the TiO2 particles is 3-5 mm; the drying is carried out at 100-120° C. for 2 hours.

4. The method according to claim 1, characterized in that: Step 2) Spreading the materials, the mass ratio of the graphite powder layer A to the graphite powder layer B is (1.5-2):1; the ratio of the TiO2 particle layer to the total mass of the graphite powder layer A and the graphite powder layer B is 11:

6.

5. The method according to claim 1, characterized in that: Step 3) calcination reduction, the calcination temperature is 750-950°C, the time is 1-2h; the sample preparation time is 1min; the ball milling speed is 300r / min, and the time is 8h.

6. The method according to claim 1, characterized in that: Step 3) calcination reduction, the particle size of the black titanium dioxide nanopowder is 50-100 nm, the oxygen vacancy concentration is 5-15wt%, and the anatase phase accounts for ≥80wt%.

7. The method according to claim 1, characterized in that: Step 4) Dispersing, the mass ratio of black titanium dioxide nanopowder to PVA solution B is 1:(0.95-1.05).

8. The method according to claim 1 or 8, characterized in that: The PVA solution B is a PVA aqueous solution with a concentration of 0.5 to 5 wt%.

9. The method according to claim 1, characterized in that: Step 5) Prepare a composite membrane, the ratio of the mass of the black titanium dioxide slurry to the paving area of ​​the glass fiber filter membrane is 2g:19.625cm 2 ; Preferably, the pore size of the glass fiber filter is 5-10μm.

10. The method according to claim 1, characterized in that: Step 5) preparing a composite membrane, wherein the vacuum degree of the filtration is ≤ 0.08 MPa, and the time is 25 to 35 seconds.

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