N-doped K-TiO2 photocatalytic material derived from NH2-MIL-125 (Ti) as well as preparation method and application of N-doped K-TiO2 photocatalytic material

Abstract

The invention discloses an NH2-MIL-125 (Ti)-derived N-doped K-TiO2 photocatalytic material as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly, preparing NH2-MIL-125 (Ti) through a solvothermal method, and preparing the photocatalytic material by taking melamine as a nitrogen source and a pore-forming agent and NH2-MIL-125 (Ti) through wet grinding, mixing and calcining; compared with traditional TiO2, the prepared K-TiO2 has a larger specific surface area, the utilization rate of visible light is increased, the forbidden band width is shortened, the photocatalyst has higher carrier separation efficiency, the degradation rate of the photocatalyst to 20 mg / L ciprofloxacin solution within one hour reaches 96.09%, the rate constant is about three times that of directly calcined MOFs, and the photocatalyst can be applied to the field of photocatalysts. And the bacillus subtilis has excellent antibiotic degradation capability and relatively high chemical stability.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, and relates to photocatalytic materials, specifically to an N-doped K-TiO2 photocatalytic material derived from NH2-MIL-125(Ti) and its preparation method and application. Background Technology

[0002] In recent years, with the rapid development of the pharmaceutical and aquaculture industries, antibiotics have been produced and used in large quantities. However, due to their incomplete biological metabolism and the limitations of traditional water treatment processes, a large amount of incompletely degraded antibiotics enters the water cycle system, causing persistent pollution. Even at low concentrations, these pollutants can induce microorganisms to produce resistance genes, posing a potential and long-term threat to the ecological environment and human health. Therefore, developing technologies for the efficient and deep degradation of antibiotic wastewater has become a critical issue that urgently needs to be addressed.

[0003] To address this issue, developing efficient, green, and low-cost antibiotic wastewater treatment technologies has become a research hotspot. Among numerous advanced oxidation technologies, photocatalysis is considered one of the most promising water treatment technologies due to its advantages such as direct utilization of solar energy, mild reaction conditions, no secondary pollution, and thorough mineralization of organic pollutants. Among various photocatalysts, titanium dioxide (TiO2) has become the earliest researched and most widely used semiconductor material in the field of photocatalysis due to its high chemical stability, non-toxicity, low cost, and high photocatalytic activity. However, titanium dioxide also has disadvantages such as a wide band gap and a fast recombination rate of photogenerated electron-hole pairs. Elemental doping in TiO2 can suppress the recombination of photogenerated carriers, thereby improving photocatalytic efficiency.

[0004] AJLMelo et al. prepared Nd-doped TiO2 nanofiber photocatalysts using electrospinning. By doping with rare earth elements, the specific surface area of ​​the material was significantly increased, reducing electron-hole recombination and extending the absorption range of TiO2 into the visible light spectrum. The degradation rate of norfloxacin under sunlight reached 99.54%, and the photocatalytic performance remained stable after five cycles of solar irradiation. However, the preparation method is complex and costly, hindering industrial-scale production (Materials Today Communications, 2025, 113946). Hailu Ashebir et al. synthesized N-doped TiO2 / BC nanocomposite materials via a sol-gel method, forming highly crystalline anatase TiO2, which shortened the band gap. In the laboratory, the degradation rate of pharmaceutical wastewater was 85.2%, but the utilization rate of visible light was low, hindering large-scale applications (Materials Science and Engineering: B, 2025, 323: 118735). Wang et al. prepared N-doped TiO2 molecularly imprinted composite materials via a sol-gel method, whose vacancy effect increased selective adsorption capacity compared to non-imprinted materials. This synergistic mechanism of adsorption and photocatalysis significantly improved the efficiency of electron-hole pair separation. Nitrogen-doped titanium dioxide enhanced visible light responsiveness through the hybridization of N2p and O2p orbitals, effectively narrowing the band gap and promoting the excitation of electron-hole pairs in the photocatalytic reaction, thereby improving the photocatalytic performance of the catalyst and providing insights for the future development of targeted photocatalytic applications. However, the material has a small specific surface area, which is not conducive to providing a large number of active sites (Chemical Physics Letters, 2025, 876: 142239). Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an N-doped K-TiO2 photocatalytic material derived from NH2-MIL-125(Ti), its preparation method, and its application. This material has a large specific surface area, high photocatalytic activity, good chemical stability, and a simple and low-cost preparation method.

[0006] To achieve the above objectives, the present invention employs the following technical solution: A method for preparing an N-doped K-TiO2 photocatalytic material derived from NH2-MIL-125(Ti) includes the following steps: S1. Add 2-aminoterephthalic acid to a mixed solvent of N,N-dimethylformamide and methanol, and stir until clear to obtain a solution with a concentration of 0.01~0.2 mol / L. Add tetrabutyl titanate to the above solution and stir continuously until dissolved, so that the concentration of tetrabutyl titanate in the solution is 0.01~0.1 mol / L. Transfer the solution to the lining of the reaction vessel and place it in an oven to react at 100~190℃ for 8~30 h. After the reaction is completed, centrifuge to collect the product, and vacuum dry to obtain NH2-MIL-125(Ti). S2. According to the mass ratio of NH2-MIL-125(Ti) to melamine (0.1~1):1, NH2-MIL-125(Ti) and melamine are mixed evenly by wet grinding. After the sample is naturally dried, it is calcined in a muffle furnace at 350~600℃ for 1~4 h in air atmosphere to finally obtain N-doped K-TiO2 photocatalytic material.

[0007] The present invention also has the following technical features: Preferably, the ratio of N,N-dimethylformamide to methanol in the mixed solvent of N,N-dimethylformamide and methanol in step one is 6:1.

[0008] Preferably, the continuous stirring time in step one is 30 to 50 minutes.

[0009] Preferably, the vacuum drying in step one is [2] drying in a vacuum drying oven at 50~150℃ for 5~24h.

[0010] Preferably, the wet grinding in step two involves adding ethanol to an agate mortar until it is slightly fluid and grinding for 10-30 minutes.

[0011] Preferably, the heating rate of the muffle furnace during the calcination process in step two is 1~8 ℃ / min.

[0012] This invention also protects a method for preparing NH4+ using the method described above. 2- MIL-125(Ti)-derived N-doped K-TiO2 photocatalytic materials and their application in photocatalytic degradation of antibiotics.

[0013] Compared with the prior art, the present invention has the following technical effects: The preparation method of this invention first prepares NH2-MIL-125(Ti) via a solvothermal method. Melamine is then used as the nitrogen source and pore-forming agent, and the mixture is wet-milled, ground, and calcined with NH2-MIL-125(Ti) to prepare a layered N-doped K-TiO2 with a rich porous structure. The product structure exhibits a layered structure composed of coarse particles. The large specific surface area and high porosity significantly enhance the photocatalytic active sites of the material. The N-doped K-TiO2 shortens the band gap, increases the utilization rate of visible light, and has higher carrier separation efficiency, exhibiting high photocatalytic activity, high chemical stability, and excellent antibiotic degradation ability. The degradation rate of a 20 mg / L ciprofloxacin solution reaches 96.09% within one hour. The preparation process of this invention is simple, controllable, and low in cost. Attached Figure Description

[0014] Figure 1 The image shows a scanning electron microscope (SEM) image of the N-doped K-TiO2 photocatalyst material derived from NH2-MIL-125(Ti) prepared in Example 1. Figure 2 The UV-Vis absorbance curve of the N-doped K-TiO2 photocatalyst material derived from NH2-MIL-125(Ti) prepared in Example 2; Figure 3 The graph shows the free radical capture performance of the N-doped K-TiO2 photocatalytic material derived from NH2-MIL-125(Ti) prepared in Example 3. Figure 4 The image shows the recycling performance of the N-doped K-TiO2 photocatalyst material derived from NH2-MIL-125(Ti) prepared in Example 4. Figure 5 The XRD patterns of the N-doped K-TiO2 photocatalyst material derived from NH2-MIL-125(Ti) prepared in Example 5 before and after use; Figure 6 The image shows the photocatalytic performance of the N-doped K-TiO2 photocatalytic material derived from NH2-MIL-125(Ti) prepared in Example 6. Detailed Implementation

[0015] The following detailed explanation of the specific content of the present invention is provided in conjunction with embodiments. These descriptions are intended to explain the present invention and not to limit it.

[0016] In the following examples, the ratio of N,N-dimethylformamide to methanol in the mixed solvent of N,N-dimethylformamide and methanol is 6:1.

[0017] Example 1 S1. 2-Aminoterephthalic acid was added to a mixed solvent of N,N-dimethylformamide and methanol and stirred until clear to obtain a solution with a concentration of 0.01 mol / L. Tetrabutyl titanate was added to the above solution and stirred for 30 min until dissolved, so that the concentration of tetrabutyl titanate in the solution was 0.01 mol / L. The solution was transferred to the lining of the reaction vessel and placed in an oven to react at 190℃ for 8 h. After the reaction was completed, the product was collected by centrifugation with methanol and dried in a vacuum drying oven at 50℃ for 24 h to obtain NH2-MIL-125(Ti). S2. According to the mass ratio of NH2-MIL-125(Ti) and melamine of 0.1:1, NH2-MIL-125(Ti) and melamine were mixed evenly in an agate mortar with ethanol added until slight flow. After the sample was dried naturally, it was calcined at 350℃ for 4 h in an air atmosphere in a muffle furnace with a heating rate of 2℃ / min. Finally, N-doped K-TiO2 photocatalytic material was obtained.

[0018] like Figure 1 These are scanning images of the K-TiO2 photocatalyst material prepared by this method, from... Figure 1 It can be seen that a layered N-doped K-TiO2 with abundant pore structure was generated, and the layers are composed of coarse particles, which greatly enhances the photocatalytic active sites of the material. This structure has not been reported in the current research on MOF-derived TiO2.

[0019] Example 2 S1. 2-Aminoterephthalic acid was added to a mixed solvent of N,N-dimethylformamide and methanol and stirred until clear to obtain a solution with a concentration of 0.02 mol / L. Butyl titanate was added to the above solution and stirred for 35 min until dissolved, so that the concentration of butyl titanate in the solution was 0.03 mol / L. The solution was transferred to the lining of the reaction vessel and placed in an oven to react at 180℃ for 26 h. After the reaction was completed, the product was collected by centrifugation with methanol and dried in a vacuum drying oven at 100℃ for 12 h to obtain NH2-MIL-125(Ti). S2. According to the mass ratio of NH2-MIL-125(Ti) and melamine of 0.2:1, NH2-MIL-125(Ti) and melamine were mixed evenly in an agate mortar with ethanol added until slightly flowing and ground for 15 min. After the sample was naturally dried, it was calcined in a muffle furnace at 400℃ in air atmosphere for 4 h. The heating rate of the muffle furnace was 2 ℃ / min. Finally, N-doped K-TiO2 photocatalytic material was obtained.

[0020] like Figure 2The UV-Vis absorbance curve of the K-TiO2 photocatalyst material prepared by this method is shown below. Figure 2 It can be seen that the absorbance of K-TiO2 photocatalyst material extends to 431 nm, which broadens the absorption range of the photocatalyst.

[0021] Example 3 S1. 2-Aminoterephthalic acid was added to a mixed solvent of N,N-dimethylformamide and methanol and stirred until clear to obtain a solution with a concentration of 0.05 mol / L. Butyl titanate was added to the above solution and stirred for 40 min until dissolved, so that the concentration of butyl titanate in the solution was 0.06 mol / L. The solution was transferred to the lining of the reaction vessel and placed in an oven at 150 °C for 18 h. After the reaction was completed, the product was collected by centrifugation with methanol and dried in a vacuum drying oven at 150 °C for 5 h to obtain NH2-MIL-125(Ti). S2. According to the mass ratio of NH2-MIL-125(Ti) and melamine of 0.3:1, NH2-MIL-125(Ti) and melamine were mixed evenly in an agate mortar with ethanol added until slightly flowing and ground for 25 min. After the sample was naturally dried, it was calcined at 500℃ in an air atmosphere in a muffle furnace for 4 h. The heating rate of the muffle furnace was 3℃ / min. Finally, N-doped K-TiO2 photocatalytic material was obtained.

[0022] like Figure 3 To assess the free radical capture performance of the K-TiO2 photocatalytic material prepared in this embodiment, from... Figure 3 It can be seen that active substances play a very important role in the degradation of antibiotics, among which ·O 2- Free radicals > h + >OH free radical, ·O 2- Free radicals are the main active species in K-TiO2 photocatalytic materials.

[0023] Example 4 S1. 2-Aminoterephthalic acid was added to a mixed solvent of N,N-dimethylformamide and methanol and stirred until clear to obtain a solution with a concentration of 0.12 mol / L. Butyl titanate was added to the above solution and stirred for 45 min until dissolved, so that the concentration of butyl titanate in the solution was 0.09 mol / L. The solution was transferred to the lining of the reaction vessel and placed in an oven to react at 100℃ for 30 h. After the reaction was completed, the product was collected by centrifugation with methanol and dried in a vacuum drying oven at 80℃ for 12 h to obtain NH2-MIL-125(Ti). S2. According to the mass ratio of NH2-MIL-125(Ti) and melamine of 0.5:1, NH2-MIL-125(Ti) and melamine were mixed evenly in an agate mortar with ethanol added until slightly flowing and ground for 20 min. After the sample was naturally dried, it was calcined at 600℃ in an air atmosphere in a muffle furnace for 1 h. The heating rate of the muffle furnace was 1℃ / min. Finally, N-doped K-TiO2 photocatalytic material was obtained.

[0024] like Figure 4 To assess the recyclability of the K-TiO2 photocatalyst material prepared in this embodiment, from... Figure 4 It can be seen that the cycle efficiency of the K-TiO2 photocatalytic material did not decrease significantly, indicating that the photocatalytic cycle degradation efficiency of the K-TiO2 photocatalytic material is very stable.

[0025] Example 5 S1. Add 2-aminoterephthalic acid to a mixed solvent of N,N-dimethylformamide and methanol, and stir until clear to obtain a solution with a concentration of 0.08 mol / L. Add tetrabutyl titanate to the above solution and stir continuously for 50 min until dissolved, so that the concentration of tetrabutyl titanate in the solution is 0.1 mol / L. Transfer the solution to the lining of the reaction vessel and place it in an oven to react at 120℃ for 10 h. After the reaction is completed, the product is collected by centrifugation with methanol and dried in a vacuum drying oven at 50~150℃ for 5~24 h to obtain NH2-MIL-125(Ti). S2. According to the mass ratio of NH2-MIL-125(Ti) and melamine of 0.8:1, NH2-MIL-125(Ti) and melamine were mixed evenly in an agate mortar with ethanol added until slightly flowing and ground for 15 min. After the sample was naturally dried, it was calcined in a muffle furnace at 400℃ in air atmosphere for 2 h. The heating rate of the muffle furnace was 5 ℃ / min. Finally, N-doped K-TiO2 photocatalytic material was obtained.

[0026] Figure 5 XRD patterns of the K-TiO2 photocatalyst material prepared in this embodiment before and after use, from... Figure 5 It can be seen that the XRD patterns of the K-TiO2 photocatalyst material did not change significantly before and after use, indicating that the K-TiO2 photocatalyst material has a stable structure.

[0027] Example 6 S1. Add 2-aminoterephthalic acid to a mixed solvent of N,N-dimethylformamide and methanol, stir until clear to obtain a solution with a concentration of 0.2 mol / L, add tetrabutyl titanate to the above solution and stir for 30 min until dissolved, so that the concentration of tetrabutyl titanate in the solution is 0.15 mol / L, transfer the solution to the lining of the reaction vessel and place it in an oven to react at 150℃ for 20 h, after the reaction is completed, wash with methanol by centrifugation and collect the product, dry in a vacuum drying oven at 100℃ for 10 h to obtain NH2-MIL-125(Ti); S2. According to the mass ratio of NH2-MIL-125(Ti) and melamine of 1:1, NH2-MIL-125(Ti) and melamine were mixed evenly in an agate mortar with ethanol added until slightly flowing and ground for 10 min. After the sample was naturally dried, it was calcined in a muffle furnace at 400℃ in air atmosphere for 3 h. The heating rate of the muffle furnace was 8 ℃ / min. Finally, N-doped K-TiO2 photocatalytic material was obtained.

[0028] Figure 6 To assess the photocatalytic performance of the K-TiO2 photocatalytic material prepared in this embodiment, from... Figure 6 It can be seen that the photocatalytic degradation efficiency of ciprofloxacin is as high as 96.09%, and the doping of N improves the photocatalytic activity.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an N-doped K-TiO2 photocatalytic material derived from NH2-MIL-125(Ti), characterized in that, Includes the following steps: S1. Add 2-aminoterephthalic acid to a mixed solvent of N,N-dimethylformamide and methanol, and stir until clear to obtain a solution with a concentration of 0.01~0.2 mol / L. Add tetrabutyl titanate to the above solution and stir continuously until dissolved, so that the concentration of tetrabutyl titanate in the solution is 0.01~0.1 mol / L. Transfer the solution to the lining of the reaction vessel and place it in an oven to react at 100~190℃ for 8~30 h. After the reaction is completed, centrifuge to collect the product, and vacuum dry to obtain NH2-MIL-125(Ti). S2. According to the mass ratio of NH2-MIL-125(Ti) to melamine (0.1~1):1, NH2-MIL-125(Ti) and melamine are mixed evenly by wet grinding. After the sample is naturally dried, it is calcined in a muffle furnace at 350~600℃ for 1~4 h in air atmosphere to finally obtain N-doped K-TiO2 photocatalytic material.

2. The preparation method of the N-doped K-TiO2 photocatalytic material derived from NH2-MIL-125(Ti) as described in claim 1, characterized in that, In step one, the ratio of N,N-dimethylformamide to methanol in the mixed solvent of N,N-dimethylformamide and methanol is 6:

1.

3. The preparation method of the N-doped K-TiO2 photocatalytic material derived from NH2-MIL-125(Ti) as described in claim 1, characterized in that, The continuous stirring time mentioned in step one is 30~50 min.

4. The preparation method of the N-doped K-TiO2 photocatalytic material derived from NH2-MIL-125(Ti) as described in claim 1, characterized in that, The vacuum drying described in step one is [1] drying in a vacuum drying oven at 50~150℃ for 5~24h.

5. The NH4+ as described in claim 1 2- The method for preparing MIL-125(Ti)-derived N-doped K-TiO2 photocatalytic material is characterized by, The wet grinding method described in step two involves adding ethanol to an agate mortar until it is slightly fluid and grinding for 10-30 minutes.

6. The NH4OH as described in claim 1 2- The method for preparing MIL-125(Ti)-derived N-doped K-TiO2 photocatalytic material is characterized by, The heating rate of the muffle furnace during the calcination process described in step two is 1~8 ℃ / min.

7. A method for preparing NH4+ using any one of claims 1 to 6 2- N-doped K-TiO2 photocatalytic material derived from MIL-125(Ti).

8. A method using NH as described in claim 7 2- Application of MIL-125(Ti)-derived N-doped K-TiO2 photocatalytic material in the photocatalytic degradation of antibiotics.

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