Iron boron-doped titanium dioxide mesocrystals, fibrous membranes thereof and applications thereof

Abstract

The present application relates to a kind of iron boron doped titanium dioxide mesocrystal and its fiber membrane and application. Iron boron doped titanium dioxide mesocrystal is synthesized by one-step calcination method, and then the dispersion liquid containing the mesocrystal and polyvinylidene fluoride is made into fiber membrane by electrospinning method. The structure of the nanoscale mesocrystal is unique, containing mesoporous, high proportion of titanium dioxide {001} high-energy crystal surface and heteroatom doping defects. The mesocrystal has abundant reactive sites, large specific surface area and enhanced light absorption, significantly improving the photocatalytic activity of titanium dioxide. The present application further combines heterogeneous Fenton-like photocatalytic technology with membrane separation technology, and the prepared fiber membrane can efficiently and quickly degrade organic pollutants. The membrane flux is high, the operation is convenient, the catalyst loss problem is solved, the recycling stability of the membrane is good, the cost is low, and it has broad application prospect.

Description

Technical Field

[0001] This invention relates to the fields of catalytic materials and wastewater treatment technology, and in particular to an iron-boron-doped titanium dioxide mesocrystalline material, its fiber membrane, and its applications. Background Technology

[0002] Efficiently degrading organic pollutants in wastewater is one of the key issues in water pollution control. Fenton's reagent is composed of Fe... 2+ Composed of H2O2, the Fenton process, as a typical advanced oxidation process (AOPs), is widely used for the treatment of organic pollutants due to its mild conditions, simple operation, and low energy consumption. Compared to the Fenton reaction, the photo-Fenton reaction under ultraviolet light has enhanced oxidation capacity and reduced H2O2 consumption. However, the homogeneous Fenton process suffers from problems such as high corrosion of reaction equipment and high intensity of iron sludge treatment, thus requiring the search for more efficient and recyclable alternative processes.

[0003] Heterogeneous Fenton-like reactions can solve the problems faced by homogeneous Fenton reactions. Heterogeneous Fenton-like reactions are highly dependent on surface active sites, as these sites can generate active species and activate H₂O₂. Simultaneously, charge transfer between the catalyst and H₂O₂ also plays a crucial role in H₂O₂ activation; sufficient charge transfer can effectively promote the catalytic activity of the catalyst. Furthermore, combining photocatalysis with Fenton-like reactions allows for the generation of holes and electrons on the catalyst surface under photoexcitation, which can activate H₂O₂ to produce oxygen free radicals (·OH, ·O₂). - This promotes iron cycling and rapidly degrades recalcitrant pollutants.

[0004] Titanium dioxide is one of the leading materials for photochemical catalysts today, and it has been extensively studied as a photo-Fenton catalyst. However, due to the limitation of its band gap, titanium dioxide is not easily excited to generate electrons and holes in the visible light region, resulting in low utilization of sunlight. Furthermore, photogenerated electrons and holes easily recombine, leading to low quantum efficiency. These limitations restrict the application of titanium dioxide. Powdered catalysts are also prone to loss during continuous reactions, and the recovery process is cumbersome and can cause secondary pollution.

[0005] Mesocrystalline structures (MSTs) are a class of nanoparticle superstructures formed by crystallographically ordered self-assembly of nanoparticles as basic units. They differ from both individual nanoparticles and bulk materials, possessing a unique ordered self-assembly structure of nanocrystals, high crystallinity, and high porosity. They readily generate and integrate outstanding mechanical, optical, and electrical properties, demonstrating broad application prospects in numerous technological fields.

[0006] Crossland et al. (Nature, 2013, 495, (7440), 215-9) synthesized porous anatase titanium dioxide single crystals using a SiO2 hard template method, which have high specific surface area and high electron mobility; Liu et al. (ACS Cent. Sci. 2015, 1, 400-40) grew titanium dioxide single crystals using an evaporation-driven directional assembly method, which have ultra-high specific surface area and a large number of defects, and dye-sensitized solar cells with light conversion efficiencies as high as 11.6% and 11.3%, respectively.

[0007] Although catalytic technology has achieved good results in water treatment, some challenges remain: first, some organic pollutants are difficult to remove; second, nano- and micron-sized catalysts are prone to loss and difficult to recover; and third, the high cost hinders widespread application. Therefore, new solutions for treating organic pollutants in water are still needed. Summary of the Invention

[0008] The purpose of this invention is to overcome the defects of the existing technology and provide a novel heterogeneous Fenton photocatalyst—iron-boron doped titanium dioxide mesocrystalline. It utilizes the high specific surface area, high electron mobility of the mesocrystalline and the crystal defects generated by heteroatom doping to expand the active sites of the catalyst, extend the available spectral range to improve photocatalytic efficiency, and further combine it with membrane separation technology to degrade organic pollutants, solve the problem of catalyst loss, and simplify operation.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] This invention provides an iron-boron-doped titanium dioxide mesocrystalline structure, wherein the mesocrystalline structure has a particle size of 300–900 nm, the nanoparticles constituting the mesocrystalline structure have a particle size of 5–80 nm, and the molar ratio of iron, boron, and titanium is (0.01–0.2):(0.1–2):1. Preferably, the nanoparticles have a particle size of 20–60 nm.

[0011] Preferably, the mesocrystalline material contains mesopores; more preferably, the pore size of the mesopores is 4–25 nm.

[0012] Preferably, the specific surface area of ​​the mesocrystalline material is 32–60 m². 2 g -1 .

[0013] Preferably, the crystal phase of titanium dioxide is anatase.

[0014] Preferably, the mesocrystalline material exhibits a cage-like skeletal structure.

[0015] Preferably, the molar ratio of iron, boron and titanium is (0.025~0.2)∶(0.25~1)∶1.

[0016] This invention maintains the exposure of the high-energy {001} crystal planes of anatase titanium dioxide after doping with iron and boron heteroatoms. The exposed crystal planes intersect with each other and participate in the formation of a mesocrystalline cage-like framework structure. As the boron content increases, the {001} crystal planes can intersect to form spheres.

[0017] The present invention also provides a method for preparing iron-boron-doped titanium dioxide mesocrystalline material, comprising the following steps: obtaining iron-boron-doped titanium dioxide mesocrystalline material by calcining an aqueous solution containing a surfactant, a titanium source, boric acid, an iron salt and an ammonium salt.

[0018] Preferably, the roasting is performed in a one-step process.

[0019] Preferably, the surfactant is a triblock copolymer, and its concentration in the aqueous solution is 2-10 wt%. More preferably, the surfactant is selected from F127, P123, or a mixture thereof. F127 and P123 are commercially available under the trade names Pluronic or Poloxamer, wherein F127 is a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer, and P123 is a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer.

[0020] Preferably, the titanium source is selected from at least one of titanium ethoxide, titanium propoxide, tetrabutyl titanate, titanium glycolate, titanium glycerol, titanium sulfate, titanium oxysulfate, titanium tetrachloride, titanium tetrafluoride, and ammonium fluorotitanate. More preferably, the titanium source is selected from at least one of titanium tetrachloride, titanium tetrafluoride, or ammonium fluorotitanate.

[0021] Preferably, the concentration of the titanium source in the above aqueous solution is 0.01 to 0.02 mol / L.

[0022] Preferably, the ferric salt is selected from ferrous salts, ferric salts, or mixtures thereof. More preferably, the ferrous salt is selected from at least one of ferrous chloride, ferrous sulfate, or ferrous nitrate, and the ferric salt is selected from at least one of ferric chloride, ferric sulfate, or ferric nitrate.

[0023] Preferably, the ammonium salt is selected from at least one of NH4NO3, NH4Cl, or NH4F. The ammonium salt acts as a buffer in the reaction. 4+ F - H2O, NH4 + The four substances are calcined at 250–300℃ to form NH4TiOF3. When the calcination temperature is raised to 400–600℃, NH4TiOF3 transforms into single-crystal TiO2. However, (NH4)2SO4 and NH4Br have higher decomposition temperatures, requiring above 400℃, and (NH4)2SO4 leaves residual acid or acid salts after decomposition, so these two ammonium salts are not used.

[0024] Preferably, the molar ratio of titanium source, boric acid, iron salt and ammonium salt, based on titanium, boron, iron and ammonium ions, is 1:(0.1-2):(0.01-0.2):(2-6). More preferably, the molar ratio of titanium source, boric acid, iron salt and ammonium salt is 1:(0.25-1):(0.025-0.2):(2-6).

[0025] Preferably, the calcination temperature is 400–800°C, and the heating rate is 1–10°C / min. -1 The constant temperature time is 0.1 to 24 hours.

[0026] Preferably, the method for preparing iron-boron-doped titanium dioxide mesocrystalline material includes the following steps: spreading an aqueous solution containing a surfactant, a titanium source, boric acid, an iron salt, and an ammonium salt on a substrate, and calcining it in a muffle furnace to obtain iron-boron-doped titanium dioxide mesocrystalline material. More preferably, the substrate is selected from at least one of silicon wafers, glass sheets, or ashless filter paper.

[0027] The water mentioned in this invention refers to deionized water.

[0028] The present invention also provides a fiber membrane containing iron-boron-doped titanium dioxide mesocrystalline material. In this invention, the fiber membrane is also referred to as an "iron-boron-doped titanium dioxide mesocrystalline fiber membrane".

[0029] Preferably, the fiber membrane further contains polyvinylidene fluoride (PVDF).

[0030] Preferably, the polyvinylidene fluoride content is 87-95 wt% of the fiber membrane.

[0031] Preferably, the content of iron-boron-doped titanium dioxide mesocrystalline material in the fiber membrane is 5-15 wt% of polyvinylidene fluoride.

[0032] The present invention also provides a method for preparing an iron boron-doped titanium dioxide mesocrystalline fiber membrane, comprising the following steps: preparing a fiber membrane by electrospinning a dispersion containing iron boron-doped titanium dioxide mesocrystalline material and polyvinylidene fluoride.

[0033] Preferably, the solvent of the dispersion is selected from N,N-dimethylformamide (DMF), acetone, or a mixture thereof. More preferably, the volume ratio of DMF to acetone is 1:(1 to 0).

[0034] Preferably, the content of polyvinylidene fluoride in the dispersion is 5-25 wt%.

[0035] Preferably, the content of iron-boron-doped titanium dioxide mesocrystalline material in the dispersion is 5-15 wt% of polyvinylidene fluoride.

[0036] Preferably, the method for preparing the dispersion includes the following steps: dissolving polyvinylidene fluoride in a solvent and stirring, then adding iron-boron-doped titanium dioxide mesocrystalline material and continuing to stir to obtain a uniform dispersion. More preferably, the dispersion is prepared at 25–80°C. More preferably, the stirring time for polyvinylidene fluoride is 1–12 hours, and after adding the iron-boron-doped titanium dioxide mesocrystalline material, stirring continues for 10–24 hours.

[0037] Electrospinning is an effective method for preparing nano / micro fiber materials. Its principle is based on the high-speed jetting of conductive fluid under a high-voltage electrostatic field. The operation process includes: loading a polymer solution or melt into the needle of an electrospinning device, overcoming surface tension under a high-voltage electrostatic field of several thousand to tens of thousands of volts to generate a charged jet stream, drying the jet stream during the jetting process and maintaining a certain amount of charge, and finally falling onto a collector to form a fiber membrane.

[0038] In this invention, preferably, the spinning rate of the electrospinning equipment is 0.5–1 mL / h. -1 The operating voltage is 11–18 kV, and the distance between the needle and the collector is 10–15 cm. Electrospinning is a general technology. When using other electrospinning equipment, the preparation of the fiber membrane of this invention can also be completed by adjusting the spinning solution parameters, equipment parameters, and spinning environment parameters according to the equipment conditions.

[0039] The iron-boron-doped titanium dioxide mesocrystalline fiber film prepared by this invention is off-white and has a smooth and flat surface.

[0040] The diameter of the fibers in the iron-boron doped titanium dioxide mesocrystalline fiber membrane of this invention is 0.1 to 2.0 μm.

[0041] The porosity of the iron-boron-doped titanium dioxide mesocrystalline fiber membrane of this invention is 68-82%.

[0042] The thickness of the fiber membrane of this invention is 50–200 μm.

[0043] The membrane flux of the fiber membrane of this invention is 25–715 L / h. -1 m -2 .

[0044] The water pressure resistance of the fiber membrane of this invention is 2 to 10 kPa.

[0045] This invention also provides the application of iron-boron-doped titanium dioxide mesocrystalline or iron-boron-doped titanium dioxide mesocrystalline fiber membranes in the degradation of organic pollutants or in the preparation of catalysts for the degradation of organic pollutants. Specifically, the iron-boron-doped titanium dioxide mesocrystalline acts as a heterogeneous Fenton photocatalyst to oxidatively degrade organic pollutants.

[0046] The present invention also provides a method for degrading organic pollutants, comprising the following steps: under light irradiation conditions, a solution containing organic pollutants flows through an iron-boron-doped titanium dioxide mesocrystalline or iron-boron-doped titanium dioxide mesocrystalline fiber membrane.

[0047] Preferably, the organic pollutant is selected from at least one of p-chlorophenol, methylene blue, tetracycline, or nitrobenzene.

[0048] Preferably, the concentration of organic pollutants in the solution is ≤30 mg / L.

[0049] Preferably, the pH value of the solution is 2 to 9; more preferably 3 to 5.

[0050] Preferably, hydrogen peroxide is also added to the solution at a concentration of 0–5 mmol / L. -1 Preferably 0.1–2 mmol / L -1 .

[0051] Preferably, during degradation, the flow rate per unit area (membrane flux) of the solution is 25–715 L / h. -1 m -2 Preferably, the illumination is ultraviolet-visible light. More preferably, the wavelength of the ultraviolet-visible light is 365–500 nm, most preferably 365–420 nm, and the irradiance is 4500–10000 W / m². -2 .

[0052] Preferably, after the solution degradation reaction containing organic pollutants is completed, the used fiber membrane can be recycled and reused. The method includes: repeatedly washing the fiber membrane with deionized water, drying it under vacuum at 40°C, and then storing it.

[0053] Compared with existing technologies, this invention provides a novel heterogeneous Fenton photocatalyst—iron-boron-doped titanium dioxide mesocrystalline. It is synthesized using a one-step calcination method, followed by electrospinning to produce a fiber membrane containing this mesocrystalline material and polyvinylidene fluoride. The preparation method is simple and low-cost. The doping with iron and boron heteroatoms forms a titanium dioxide mesocrystalline material with a unique morphology, high energy exposure, and a high proportion of {001} crystal planes. Compared with anatase titanium dioxide, the band gap is reduced to 3.0–2.8 eV, thus enhancing the separation of photogenerated electrons and holes, promoting charge migration, and forming abundant oxygen vacancies on the catalyst surface, increasing surface active sites, which is beneficial for the generation of active species, improving catalytic efficiency, and enhancing light absorption. The prepared fiber membrane has a small fiber diameter, good continuity, is self-supporting in the reaction, and is not prone to aggregation. Moreover, the fiber membrane combines the advantages of photo-Fenton advanced oxidation technology and membrane separation technology, which can improve the removal capacity of organic pollutants and efficiently and rapidly degrade organic pollutants, such as achieving a removal rate of over 98% for p-chlorophenol and over 78% for TOC in solution. Simultaneously, it reduces catalyst loss, solves the catalyst recovery problem, achieves high membrane flux, and demonstrates good stability in membrane recycling. This invention provides a more efficient way to treat wastewater, protect the environment, and improve water quality, with broad application prospects. Attached Figure Description

[0054] Figure 1 The images show scanning electron microscope (SEM) images (left) and transmission electron microscope (TEM) images (right) of iron boron-doped titanium dioxide mesocrystalline material. The bottom corner of the right image shows the FFT plot.

[0055] Figure 2 The nitrogen isothermal adsorption-desorption lines (left) and pore size distribution (right) of iron-boron doped titanium dioxide mesocrystalline material are shown.

[0056] Figure 3 The ultraviolet diffuse reflectance spectrum (left) and band gap diagram (right) of iron-boron doped titanium dioxide mesocrystalline material are shown.

[0057] Figure 4 The diagram shows an electrospinning apparatus (left) and a photograph of the appearance of an iron-boron-doped titanium dioxide mesocrystalline fiber membrane (right).

[0058] Figure 5 Scanning electron microscope (SEM) images before and after the application of iron boron-doped titanium dioxide mesocrystalline fiber membranes to degrade organic pollutants.

[0059] Figure 6 X-ray diffraction (XRD) images of iron boron-doped titanium dioxide mesocrystalline material and its fiber membrane.

[0060] Figure 7 The graph shows the efficiency of removing p-chlorophenol using the iron-boron-doped titanium dioxide mesocrystalline fiber membrane in Example 1.

[0061] Figure 8 The efficiency of removing different concentrations of p-chlorophenol using an iron-boron-doped titanium dioxide mesocrystalline fiber membrane in Example 31 is shown in the graph.

[0062] Figure 9 This is a diagram showing the effect of the fiber membrane cycle test in Example 34. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0064] Example 1

[0065] Add 2g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride (12.8mmol) with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate (8.4mmol) with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixtures. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0066] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The operating voltage was 14kV, the distance between the needle and the collector was 12cm, and spinning was performed. The aluminum foil was fixed on a roller for collection, resulting in a 403cm thick iron-boron doped titanium dioxide mesocrystalline fiber membrane. 2 Thickness 80μm.

[0067] A 13cm thick iron-boron-doped titanium dioxide mesocrystalline fiber membrane was prepared. 2 The degradation of p-chlorophenol was carried out under light irradiation. The wavelength of the light was 420 nm, and the irradiance was 5500 W / m².-2 The p-chlorophenol solution contained 10 mg / L of p-chlorophenol and 0.75 mmol / L of hydrogen peroxide. -1 The solution pH was 3. 15 mL of p-chlorophenol solution was added at a rate of 0.6 mL / min. -1 The flow rate was such that the fiber membrane was passed through it, and the degradation time was 25 minutes.

[0068] The prepared mesocrystalline structures and their fibrous membranes were identified using various testing methods.

[0069] Elemental analysis showed that the molar ratio of iron, boron, and titanium in the mesocrystalline material was 0.05:1:1.

[0070] Figure 1 The images show SEM, TEM, and FFT images of the mesocrystalline structure. After elemental doping, the particles exhibit a cage-like skeletal structure, with exposed titanium dioxide {001} high-energy crystal planes interlocking and assembled. Mesopores are uniformly distributed within the particles. The mesocrystalline particle size is approximately 700 nm, while the nanoparticles constituting the mesocrystalline structure have a size of 20–60 nm. The FFT results show a single-crystal diffraction lattice.

[0071] Figure 2 The left image shows the nitrogen isotherm adsorption-desorption curves and the pore size distribution diagram (right image) for the mesocrystalline titanium dioxide. In the figures, MST, Fe-MST, and FeB-MST represent single-crystal titanium dioxide, iron-doped titanium dioxide, and the iron-boron-doped titanium dioxide mesocrystalline titanium dioxide of this invention, respectively. The BET results show a type IV nitrogen isotherm adsorption-desorption curve, indicating that FeB-MST has a mesoporous structure with a pore size of approximately 15-25 nm and a specific surface area of ​​43 m². 2 g -1 .

[0072] Figure 3 The left image shows the diffuse reflectance spectrum (DRES) and the right image shows the band gap of the mesocrystalline titanium dioxide. The DRES spectrum indicates that the absorption in the visible light region of the catalyst is significantly enhanced after iron-boron doping. The structure of the doped system changes after boron atom doping, resulting in a red shift in UV absorption. The calculated band gap of FeB-MST is 2.95 eV, compared to the 3.20 eV band gap of anatase titanium dioxide. The narrower band gap of the iron-boron-doped mesocrystalline titanium dioxide indicates a lower electron-hole recombination rate in the titanium dioxide system, leading to higher photocatalytic activity.

[0073] Figure 4 The diagram shows an electrospinning apparatus (left) and a photograph of the appearance of an iron-boron-doped titanium dioxide mesocrystalline fiber membrane (right). The membrane is off-white with a smooth, flat surface.

[0074] Figure 5Scanning electron microscopy (SEM) images of the iron-boron-doped titanium dioxide mesocrystalline fiber membrane before and after the degradation of organic pollutants. The images show that the fiber diameter was 0.1–1.5 μm before the reaction, and no change was observed in the SEM images after the reaction, indicating good membrane stability.

[0075] Figure 6 These are X-ray diffraction (XRD) images of iron-boron-doped titanium dioxide mesocrystalline particles and their fibrous films. PVDF represents PVDF, FeB-MST represents iron-boron-doped titanium dioxide mesocrystalline particles, FeB-MST@PVDF represents iron-boron-doped titanium dioxide mesocrystalline fibrous films, and PDF#73-1764 is the standard card for anatase titanium dioxide. The XRD results indicate that the mesocrystalline titanium dioxide particles have a pure anatase phase.

[0076] Figure 7 This is a graph showing the efficiency of the iron-boron-doped titanium dioxide mesocrystalline fiber membrane in removing p-chlorophenol in Example 1. The results show that within 25 minutes, the removal rate of p-chlorophenol reached 98%, and the TOC removal rate of the filtered solution was 78%. Compared with the treatment effect of a pure PVDF membrane, the iron-boron-doped titanium dioxide mesocrystalline fiber membrane improved the removal rate of chlorophenol by approximately 30% and the TOC by approximately 20%.

[0077] Example 2

[0078] 4g of P123 was added to 49mL of deionized water and stirred for 3 hours to obtain solution A. Ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water were stirred for 30 minutes to obtain solution B. 1.59g of titanium tetrafluoride was mixed with 20mL of deionized water to obtain solution C. 1.66g of ammonium fluorotitanate was mixed with 20mL of deionized water to obtain solution D. Solutions A, B, C, and D were mixed in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Boric acid was weighed according to a titanium to boron molar ratio of 1:1 and dissolved in the above mixture. Finally, the total mixture was spread evenly on a silicon wafer. The silicon wafer was placed in a muffle furnace for calcination at a heating rate of 5℃ min⁻¹ and held at 600℃ for 1 hour to obtain iron-boron doped titanium dioxide mesocrystalline powder.

[0079] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron-boron-doped titanium dioxide mesocrystalline fibers (8 wt% of PVDF) were added, and stirring continued for 10 hours to obtain the spinning solution. Electrospinning apparatus parameters were set as follows: electrospinning rate 0.6 mL h⁻¹, operating voltage 14 kV, and distance between needle and collector 12 cm. Spinning was performed, and aluminum foil was fixed on a roller for collection, resulting in an iron-boron-doped titanium dioxide mesocrystalline fiber membrane.

[0080] Example 3

[0081] Add 2g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric sulfate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0082] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0083] Example 4

[0084] 2g of F127 was added to 49mL of deionized water and stirred for 3 hours to obtain solution A. Ferrous sulfate heptahydrate (molar ratio Ti:Fe = 1:0.15), 5g of ammonium nitrate, and 20mL of deionized water were stirred for 30 minutes to obtain solution B. 1.59g of titanium tetrafluoride was mixed with 20mL of deionized water to obtain solution C. 1.66g of ammonium fluorotitanate was mixed with 20mL of deionized water to obtain solution D. Solutions A, B, C, and D were mixed in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Boric acid was weighed according to a titanium to boron molar ratio of 1:1 and dissolved in the above mixture. Finally, the total mixture was spread evenly on a silicon wafer. The silicon wafer was placed in a muffle furnace for calcination at a heating rate of 5℃ min⁻¹ and held at 600℃ for 1 hour to obtain iron-boron doped titanium dioxide mesocrystalline powder.

[0085] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron-boron-doped titanium dioxide mesocrystalline fibers (8 wt% of PVDF) were added, and stirring continued for 10 hours to obtain the spinning solution. Electrospinning apparatus parameters were set as follows: electrospinning rate 0.6 mL h⁻¹, operating voltage 14 kV, and distance between needle and collector 12 cm. Spinning was performed, and aluminum foil was fixed on a roller for collection, resulting in an iron-boron-doped titanium dioxide mesocrystalline fiber membrane.

[0086] Example 5

[0087] Add 6g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.025), 5g of ammonium fluoride, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:0.5 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0088] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0089] Example 6

[0090] Add 6g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.075), 5g of ammonium chloride, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:0.5 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0091] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0092] Example 7

[0093] Add 4g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.02), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrachloride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:0.8 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0094] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h.-1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0095] Example 8

[0096] Add 8g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.5:0.5. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0097] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0098] Example 9

[0099] Add 8g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.1), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:1:0. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixtures. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0100] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0101] Example 10

[0102] Add 8g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0:1. Weigh boric acid according to a titanium to boron molar ratio of 1:0.25 and dissolve it in the above mixtures. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0103] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0104] Example 11

[0105] Add 2g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.2), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1.5 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0106] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0107] Example 12

[0108] 10g of F127 was added to 49mL of deionized water and stirred for 3 hours to obtain solution A. Ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water were stirred for 30 minutes to obtain solution B. 1.59g of titanium tetrafluoride was mixed with 20mL of deionized water to obtain solution C. 1.66g of ammonium fluorotitanate was mixed with 20mL of deionized water to obtain solution D. Solutions A, B, C, and D were mixed in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Boric acid was weighed according to a titanium to boron molar ratio of 1:2 and dissolved in the above mixture. Finally, the total mixture was spread evenly on a silicon wafer. The silicon wafer was placed in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0109] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h.-1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0110] Example 13

[0111] Add 2g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.1), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:0.5 and dissolve it in the above mixtures. Finally, spread the total mixture evenly on ashless filter paper. Place the ashless filter paper in a muffle furnace for calcination at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0112] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0113] Example 14

[0114] Add 6g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:0.5 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 10℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0115] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0116] Example 15

[0117] Add 4g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 400℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0118] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0119] Example 16

[0120] Add 5g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.025), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:0.75 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 4 hours to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0121] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0122] Example 17

[0123] Add 2g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0124] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h.-1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0125] Example 18

[0126] Add 4g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 10g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:0.75 and dissolve it in the above mixtures. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0127] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0128] Example 19

[0129] Add 4g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.2), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 0.80g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0130] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0131] Example 20

[0132] Add 4g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 0.88g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1.5 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0133] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0134] Example 21

[0135] Add 5g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixtures. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0136] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 20 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring was continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0137] Example 22

[0138] Add 5g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixtures. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0139] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 10 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for another 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h.-1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0140] Example 23

[0141] Add 5g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.1), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixtures. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0142] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 60°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0143] Example 24

[0144] Add 2g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0145] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.8 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0146] Example 25

[0147] Add 2g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:0.75 and dissolve it in the above mixtures. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0148] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 11kV, the distance between the needle and the collector is 12cm, spinning is performed, and the aluminum foil is fixed on the roller for collection to obtain an iron boron doped titanium dioxide mesocrystalline fiber membrane.

[0149] Example 26

[0150] Add 2g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.075), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0151] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:1) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h. -1 The working voltage is 14kV, the distance between the needle and the collector is 14cm, spinning is performed, and the aluminum foil is fixed on the roller for collection to obtain an iron boron doped titanium dioxide mesocrystalline fiber membrane.

[0152] Example 27

[0153] Add 8g of F127 to 49mL of deionized water and stir for 3 hours to obtain solution A. Stir ferric nitrate nonahydrate (molar ratio Ti:Fe = 1:0.05), 5g of ammonium nitrate, and 20mL of deionized water for 30 minutes to obtain solution B. Mix 1.59g of titanium tetrafluoride with 20mL of deionized water to obtain solution C. Mix 1.66g of ammonium fluorotitanate with 20mL of deionized water to obtain solution D. Mix solutions A, B, C, and D in a volume ratio of A:B:C:D = 2:1:0.2:0.8. Weigh boric acid according to a titanium to boron molar ratio of 1:1 and dissolve it in the above mixture. Finally, spread the total mixture evenly on a silicon wafer. Place the silicon wafer in a muffle furnace for baking at a heating rate of 5℃ / min. -1 The mixture was kept at 600℃ for 1 hour to obtain iron boron-doped titanium dioxide mesocrystalline powder.

[0154] PVDF was dissolved in DMF and acetone (volume ratio DMF:acetone = 1:0) to obtain a 15 wt% PVDF solution. After stirring at 30°C for 2 hours, iron boron-doped titanium dioxide mesocrystalline material (8 wt% of PVDF) was added, and stirring continued for 10 hours to obtain the spinning solution. The electrospinning apparatus parameters were set, with an electrospinning rate of 0.6 mL / h.-1 The working voltage is 14kV, the distance between the needle and the collector is 12cm, the spinning is performed, the aluminum foil is fixed on the roller for collection, and iron boron doped titanium dioxide mesocrystalline fiber membrane is obtained.

[0155] The iron-boron-doped titanium dioxide mesocrystalline materials and their fiber films prepared in Examples 2-27 were identified using various test methods from Example 1. The identification conclusions were similar to those of Example 1, and will not be detailed here.

[0156] Example 28

[0157] A 13 cm thick iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 1 2 The degradation of p-chlorophenol was carried out under light irradiation. The wavelength of the light was 365 nm, and the irradiance was 5500 W / m². -2 The p-chlorophenol solution contained 10 mg / L of p-chlorophenol and 0.75 mmol / L of hydrogen peroxide. -1 The solution pH is 4. 15 mL of p-chlorophenol solution was added at a rate of 2 mL / min. -1 When the iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 1 was passed through at a flow rate of 7.5 minutes, the fiber membrane achieved a 93% removal rate of p-chlorophenol and a 69% TOC removal rate in the filtered solution. After the p-chlorophenol solution was circulated through the membrane for another 7.5 minutes, the fiber membrane achieved a 98% removal rate of p-chlorophenol and a 80% TOC removal rate.

[0158] Example 29

[0159] A 13 cm thick iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 19 2 The degradation of p-chlorophenol was carried out under light irradiation. The wavelength of the light was 420 nm, and the irradiance was 8000 W / m². -2 The p-chlorophenol solution contained 10 mg / L of p-chlorophenol and 1.5 mmol / L of hydrogen peroxide. -1 The solution pH is 4. 16 mL of p-chlorophenol solution was added at a rate of 4 mL / min. -1 When the iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 1 was passed through at a flow rate of 4 minutes, the fiber membrane achieved a 91% removal rate of p-chlorophenol and a 67% TOC removal rate in the filtered solution. After the p-chlorophenol solution was circulated through the membrane for another 4 minutes, the fiber membrane achieved a 97% removal rate of p-chlorophenol and a 78% TOC removal rate.

[0160] Example 30

[0161] A 13 cm thick iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 24 2The degradation of p-chlorophenol was carried out under light irradiation. The wavelength of the light was 420 nm, and the irradiance was 5500 W / m². -2 The p-chlorophenol solution contained 25 mg / L of p-chlorophenol and 0.75 mmol / L of hydrogen peroxide. -1 The solution pH is 4. 25 mL of p-chlorophenol solution was added at a rate of 5 mL / min. -1 When the iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 1 was passed through at a flow rate of 5 minutes, the fiber membrane removed 71% of the p-chlorophenol and 45% of the TOC in the filtered solution. After the p-chlorophenol solution was circulated through the membrane for another 20 minutes, the fiber membrane removed 93% of the p-chlorophenol and 74% of the TOC.

[0162] Example 31

[0163] A 13 cm thick iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 1 2 Different concentrations of p-chlorophenol were degraded under light irradiation. The wavelength of the light was 420 nm, and the irradiance was 4500 W / m². -2 The p-chlorophenol solutions contained p-chlorophenol concentrations of 5 mg / L, 10 mg / L, 20 mg / L, and 30 mg / L, and hydrogen peroxide concentrations of 2 mmol / L. -1 The solution pH was 4. 125 mL of p-chlorophenol solutions of different concentrations were used at 10 mL / min... -1 The flow rate was such that the iron boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 1 was passed through it, and the membrane was continuously degraded over a period of 25 minutes.

[0164] Figure 8 The efficiency of removing different concentrations of p-chlorophenol using iron-boron-doped titanium dioxide mesocrystalline fiber membranes is shown in the figure. Figure 8 The results show that within 25 minutes, the fiber membrane achieved a removal rate of over 85% for 5–20 mg / L p-chlorophenol, indicating good treatment efficiency. However, the removal rate for 30 mg / L p-chlorophenol was only 65%, which may be related to the higher solution flow rate.

[0165] Example 32

[0166] A 13 cm thick iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 1 2 Methylene blue was degraded under light irradiation. The wavelength of the light was 420 nm, and the irradiance was 5500 W / m². -2 The methylene blue solution contained 10 mg / L of methylene blue and 0.75 mmol / L of hydrogen peroxide. -1 The solution pH is 5. 15 mL of methylene blue solution is added at a rate of 1 mL / min. -1The solution was flowed through the iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 1 at a flow rate of [value missing], and the degradation time was 15 minutes. The fiber membrane achieved a 90% removal rate of methylene blue, and the filtered solution achieved a 71% removal rate of TOC.

[0167] Example 33

[0168] A 13 cm thick iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 1 2 Tetracycline is degraded under light irradiation. The wavelength of the light is 420 nm, and the irradiance is 5500 W / m². -2 The tetracycline solution contained 10 mg / L of tetracycline and 0.75 mmol / L of hydrogen peroxide. -1 The solution pH was 3. 15 mL of tetracycline solution was added at 0.6 mL / min. -1 The solution was passed through the iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 1 at a flow rate of [value missing], and the degradation time was 25 minutes. The fiber membrane achieved a 96% removal rate of tetracycline, and the filtered solution achieved a 75% removal rate of TOC.

[0169] Example 34

[0170] A 13cm thick iron-boron-doped titanium dioxide mesocrystalline fiber membrane prepared in Example 2 2 The degradation of p-chlorophenol under light irradiation was investigated to test its recyclability. The wavelength of the light was 365 nm, and the irradiance was 10000 W / m². -2 The p-chlorophenol solution contained 10 mg / L of p-chlorophenol and 0.75 mmol / L of hydrogen peroxide. -1 The solution pH is 3. 25 mL of p-chlorophenol solution was added at a rate of 1 mL / min. -1 The flow rate was such that the fiber membrane was passed through it, and the degradation time was 25 minutes. The used fiber membrane was washed with deionized water, vacuum dried at 40°C, and then recycled 5 times.

[0171] Figure 9 This image shows the results of a cyclic test of the fiber membrane. It indicates that after five cycles, the removal rate of p-chlorophenol by the fiber membrane remained above 92%, and the membrane flux showed almost no change. SEM images before and after the cycle also show that the membrane's microstructure remained unchanged, indicating good membrane stability and reusability.

Claims

1. A method for preparing iron-boron-doped titanium dioxide mesocrystalline material, characterized in that, Includes the following steps: Iron boron-doped titanium dioxide mesocrystalline material was obtained by one-step calcination of an aqueous solution containing surfactant, titanium source, boric acid, iron salt and ammonium salt. The surfactant is a triblock copolymer, the concentration of the surfactant in the aqueous solution is 2 to 10 wt%, the concentration of the titanium source in the aqueous solution is 0.01 to 0.02 mol / L, and the molar ratio of titanium source, boric acid, iron salt and ammonium salt is 1:(0.1 to 2):(0.01 to 0.2):(2 to 6) based on titanium, boron, iron and ammonium ions. The titanium source is titanium tetrafluoride and ammonium fluorotitanate; The iron salt is selected from divalent iron salts, trivalent iron salts, or mixtures thereof; The ammonium salt is selected from at least one of NH4NO3, NH4Cl or NH4F.

2. A mesocrystalline form of iron-boron-doped titanium dioxide, characterized in that, The mesocrystalline material was prepared according to the preparation method described in claim 1, wherein the particle size of the mesocrystalline material is 300-900 nm, the particle size of the nanoparticles constituting the mesocrystalline material is 5-80 nm, and the molar ratio of the three elements iron, boron, and titanium is (0.01-0.2):(0.1-2):

1. The mesocrystalline material contains mesopores with a pore size of 4~25 nm. The specific surface area of ​​the mesocrystalline material is 32 to 60 m². 2 g -1 ; Titanium dioxide has anatase crystal phase; The mesocrystalline structure exhibits a cage-like framework structure. After doping with iron and boron heteroatoms, the high-energy crystal planes of anatase titanium dioxide {001} are exposed, and the exposed crystal planes intersect with each other, participating in the formation of the cage-like framework structure of the mesocrystalline structure.

3. A fiber membrane, characterized in that, It contains the iron-boron-doped titanium dioxide mesocrystalline material as described in claim 2.

4. The fiber membrane according to claim 3, characterized in that, The fiber membrane also contains polyvinylidene fluoride (PVDF), with PVDF content ranging from 87 to 95 wt% of the fiber membrane. The content of iron-boron-doped titanium dioxide mesocrystalline material is 5 to 15 wt% of PVDF, and the fiber diameter is 0.1 to 2.0 μm.

5. A method for preparing the fiber membrane according to claim 4, characterized in that, Includes the following steps: A dispersion containing iron boron-doped titanium dioxide mesocrystalline material and polyvinylidene fluoride was electrospinned to form a fiber membrane.

6. The application of the iron-boron-doped titanium dioxide mesocrystalline membrane of claim 2 or the fiber membrane of claim 3 or 4 in the degradation of organic pollutants.

7. A method for degrading organic pollutants, characterized in that, Includes the following steps: Under illumination, a solution containing organic contaminants flows through the iron-boron-doped titanium dioxide mesocrystalline membrane of claim 2 or the fiber membrane of claim 3 or 4.

8. The degradation method according to claim 7, characterized in that, The organic pollutant is selected from at least one of p-chlorophenol, methylene blue, tetracycline, or nitrobenzene.

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