Preparation method and application of MIL-88B(Fe) / ZnTi-LDH photocatalyst

Abstract

The present invention discloses a preparation method of a MIL-88B(Fe) / ZnTi-LDH photocatalyst and its application in the field of photocatalytic degradation of antibiotics. The method comprises the following steps: S1, preparation of MIL-88B(Fe) powder; S2, preparation of ZnTi-LDH powder; S3, and further preparation of the MIL-88B(Fe) / ZnTi-LDH photocatalytic composite material by a solution casting method using N,N-dimethylformamide as a solvent. Compared with existing high-efficiency metal-organic frameworks or layered double hydroxides, the main elements of the MIL-88(Fe) / ZnTi-LDH composite material are not only abundant in source, with inexpensive raw materials, but also low in toxicity. More importantly, the material exhibits a high removal effect on tetracycline, and has certain practical application value.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalyst preparation, and in particular to a preparation method and application of a MIL-88B(Fe) / ZnTi-LDH photocatalyst. Background Art

[0002] Tetracycline, a broad-spectrum antibiotic, has been widely used in human medicine, veterinary medicine, and animal husbandry and aquaculture to prevent or treat bacterial infections. However, overuse of antibiotics can lead to bacterial resistance, resulting in an alarming increase in the number of antibiotic-resistant bacteria. Due to its excellent physical and chemical stability, tetracycline is difficult to degrade using traditional wastewater treatment methods. Photocatalysis has proven to be an effective strategy for the efficient removal of antibiotics from water, making the development of highly active, environmentally friendly, and low-cost photocatalysts crucial. Metal-organic frameworks (MOFs), crystalline microporous materials constructed from coordinated metal oxo groups and organic linkers, have attracted widespread attention in the environmental field due to their high surface area, tunable pore size, and uniformly distributed active sites. Among various MOFs, iron-based MILs (MILs) with the Fe3-μ3-oxo group exhibit outstanding visible light responsiveness. MIL-88B(Fe), a member of this class of iron-based MILs, is characterized by its stable structure, ease of synthesis, and environmental friendliness, making it a popular choice for the degradation of environmental pollutants. However, the rapid recombination of electron-hole pairs remains a major obstacle to the practical application of MIL-88B(Fe). Layered double hydroxides (LDHs) are two-dimensional, layered inorganic compounds resembling hydrotalcites (or anionic clays). They have attracted considerable attention due to their unique two-dimensional structure, large specific surface area, tunable band gap, low cost of preparation, environmental friendliness, and excellent photocatalytic performance. Zinc-titanium layered double hydroxides (Zn-Ti) are n-type semiconductor materials, which are simple to prepare and environmentally friendly and are commonly used as photocatalytic materials. Therefore, the present invention prepared a complex of two-dimensional Zn-Ti layered double hydroxides and MIL-88B(Fe) by solution casting and applied it to the degradation of tetracycline in water. Summary of the Invention

[0003] The purpose of the present invention is to solve the technical problems existing in the prior art and provide a preparation method of a MIL-88B(Fe) / ZnTi-LDH photocatalyst and its application.

[0004] To achieve the above object, the present invention provides a technical solution: a method for preparing a MIL-88B(Fe) / ZnTi-LDH photocatalyst, the method comprising the following steps:

[0005] S1. Preparation of MIL-88B(Fe) powder: 60-70 parts by weight of ferric chloride hexahydrate, 30-40 parts of terephthalic acid, and 3-4 mL of sodium hydroxide solution are added to 50-80 mL of N,N-dimethylformamide and dissolved in a beaker. The mixture is ultrasonicated for 10-30 minutes and stirred for 20-40 minutes. The mixture is then hydroheated in an oven at 100-120°C for 12-16 hours, washed, and dried to obtain MIL-88B(Fe) powder.

[0006] S2. Preparation of ZnTi-LDH powder: Add 30-40 parts by weight of zinc nitrate hexahydrate and 10-20 parts of tetrabutyl titanate to an ethanol solution, stir for 15-20 minutes, then add 50-60 parts of urea, continue stirring for 10-15 minutes, and hydroheat at 100-120° C. for 18-24 hours to obtain the desired ZnTi-LDH powder;

[0007] S3. Preparation of MIL-88B(Fe) / ZnTi-LDH photocatalytic composite material by solution casting method: The MIL-88B(Fe) powder obtained in step S1 and the ZnTi-LDH powder obtained in step S2 are simultaneously placed in a beaker containing a specific solvent and ultrasonicated for 10 to 20 minutes, then slowly stirred at a temperature of 50 to 60°C until all the solvent is evaporated, and then placed in an oven at 100 to 150°C and maintained for 3 to 5 hours; the obtained powder is ground to obtain a MIL-88B(Fe) / ZnTi-LDH photocatalytic composite material, which is recorded as MZ-X, where X is the mass percentage of ZnTi-LDH in the composite.

[0008] Preferably, the MIL-88B(Fe) / ZnTi-LDH photocatalytic composite material obtained in step S3 constructs an nn-type heterojunction between MIL-88B(Fe) and ZnTi-LDH.

[0009] Preferably, in step S1, the molar ratio of ferric chloride hexahydrate to terephthalic acid is (0.8-1.2):1, and the solubility of sodium hydroxide is 2-4 mol / L.

[0010] Preferably, the molar ratio of titanium ions to zinc ions in step S2 is (1-2):5, and 60-80 mL of ethanol solution is added in step S2, and the volume ratio of the ethanol solution is ethanol:deionized water is (1-2):1.

[0011] Preferably, the specific solvent in step S3 is N,N-dimethylformamide, and the volume is 5 to 10 mL.

[0012] Preferably, in step S3, the mass ratio of the ZnTi-LDH powder to the total mass of the mixed powder of MIL-88B(Fe) and ZnTi-LDH is (1-5):10.

[0013] The present invention also discloses an application of a MIL-88B(Fe) / ZnTi-LDH photocatalyst, including an MIL-88B(Fe) / ZnTi-LDH composite material prepared by any of the above-mentioned methods for preparing a MIL-88B(Fe) / ZnTi-LDH photocatalyst, which is applied in the field of photocatalytic degradation of antibiotics.

[0014] Beneficial effects of the present invention:

[0015] 1. Compared with pure MIL-88B(Fe), the present invention improves the separation of electron-hole pairs by coupling with two-dimensional ZnTi-LDH, enhances the photocatalytic activity of the material, and has an excellent removal effect on tetracycline.

[0016] 2. Compared with other composite methods, the present invention adopts solution casting method, which is simple to operate, has low requirements on equipment, short reaction time, is conducive to large-scale production, and greatly reduces production costs.

[0017] 3. Compared with existing high-efficiency metal-organic frameworks or layered double hydroxides, the MIL-88(Fe) / ZnTi-LDH composite material of the present invention has abundant sources of main elements, cheap raw materials, and low toxicity, and has certain practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] Figure 1 The activity diagram of the composite material obtained in Examples 1 to 3 for photodegradation of tetracycline;

[0020] Figure 2 is a curve of tetracycline adsorption volume of the composite material obtained in Examples 1 to 3;

[0021] Figure 3 The XRD patterns of the composite materials obtained in Examples 1 to 3 are shown. DETAILED DESCRIPTION

[0022] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0023] Reference Figure 1-Figure 3A preferred embodiment of the present invention is a method for preparing a MIL-88B(Fe) / ZnTi-LDH photocatalyst, characterized in that the method comprises the following steps:

[0024] S1. Preparation of MIL-88B(Fe) powder: 60-70 parts by weight of ferric chloride hexahydrate, 30-40 parts of terephthalic acid, and 3-4 mL of sodium hydroxide solution are added to 50-80 mL of N,N-dimethylformamide and dissolved in a beaker. The mixture is ultrasonicated for 10-30 minutes and stirred for 20-40 minutes. The mixture is then hydroheated in an oven at 100-120°C for 12-16 hours, washed, and dried to obtain MIL-88B(Fe) powder.

[0025] S2. Preparation of ZnTi-LDH powder: Add 30-40 parts by weight of zinc nitrate hexahydrate and 10-20 parts of tetrabutyl titanate to an ethanol solution, stir for 15-20 minutes, then add 50-60 parts of urea, continue stirring for 10-15 minutes, and hydroheat at 100-120° C. for 18-24 hours to obtain the desired ZnTi-LDH powder;

[0026] S3. Preparation of MIL-88B(Fe) / ZnTi-LDH photocatalytic composite material by solution casting method: The MIL-88B(Fe) powder obtained in step S1 and the ZnTi-LDH powder obtained in step S2 are simultaneously placed in a beaker containing a specific solvent and ultrasonicated for 10 to 20 minutes, then slowly stirred at a temperature of 50 to 60°C until all the solvent is evaporated, and then placed in an oven at 100 to 150°C and maintained for 3 to 5 hours; the obtained powder is ground to obtain a MIL-88B(Fe) / ZnTi-LDH photocatalytic composite material, which is recorded as MZ-X, where X is the mass percentage of ZnTi-LDH in the composite.

[0027] In this embodiment, the MIL-88B(Fe) / ZnTi-LDH photocatalytic composite material obtained in step S3 constructs an nn-type heterojunction between MIL-88B(Fe) and ZnTi-LDH, inhibiting the recombination of photogenerated electron-hole pairs, thereby improving the photocatalytic activity of the composite; under visible light irradiation for 40 minutes, the optimally proportioned composite has a tetracycline removal rate of 93.13%; in addition, the composite material also has excellent adsorption performance for TC, and has potential applications in the field of photocatalytic wastewater treatment.

[0028] In this embodiment, the molar ratio of ferric chloride hexahydrate to terephthalic acid in step S1 is (0.8-1.2):1, and the solubility of sodium hydroxide is 2-4 mol / L.

[0029] In this embodiment, the molar ratio of titanium ions to zinc ions in step S2 is (1-2):5, and 60-80 mL of ethanol solution is added in step S2, and the volume ratio of the ethanol solution is ethanol:deionized water is (1-2):1.

[0030] In this embodiment, the specific solvent in step S3 is N,N-dimethylformamide, and the volume is 5 to 10 mL.

[0031] In this embodiment, in step S3, the mass ratio of the ZnTi-LDH powder to the total mass of the mixed powder of MIL-88B(Fe) and ZnTi-LDH is (1-5):10.

[0032] The present invention also discloses an application of a MIL-88B(Fe) / ZnTi-LDH photocatalyst, and also includes the application of the MIL-88B(Fe) / ZnTi-LDH composite material prepared by the preparation method of any of the above-mentioned MIL-88B(Fe) / ZnTi-LDH photocatalysts in the field of photocatalytic degradation of antibiotics.

[0033] The present invention combines MIL-88B (Fe) with ZnTi-LDH to achieve efficient adsorption and photodegradation of tetracycline.

[0034] Compared with pure MIL-88B(Fe), the present invention improves the separation of electron-hole pairs and enhances the photocatalytic activity of the material by coupling with a two-dimensional ZnTi-LDH, thereby having an excellent removal effect on tetracycline. Compared with other composite methods, the present invention adopts a solution casting method, which is simple to operate, has low requirements on equipment, and has a short reaction time, is conducive to large-scale production, and greatly reduces production costs. Compared with existing high-efficiency metal-organic frameworks or layered double hydroxides, the MIL-88(Fe) / ZnTi-LDH composite material has abundant sources of main elements, cheap raw materials, and low toxicity, and has certain practical application value.

[0035] As a preferred embodiment of the present invention, it may also have the following additional technical features:

[0036] Example 1:

[0037] Step S1, Preparation of MIL-88B(Fe) Powder: 2.7000 g of ferric chloride hexahydrate and 1.1600 g of terephthalic acid were added to 50 mL of N,N-dimethylformamide and 4 mL of sodium hydroxide solution (4 mol / L), followed by sonication for 30 minutes and magnetic stirring for 30 minutes. The resulting mixture was placed in a reactor and maintained at 100°C for 12 hours. The solid was collected by centrifugation at 8000 rpm for 5 minutes, then stirred overnight in deionized water, centrifuged, washed, and then dried at 60°C for 12 hours to obtain MIL-88B(Fe) powder.

[0038] Step S2, Preparation of ZnTi-LDH Powder: Dissolve 2.1860g of zinc nitrate hexahydrate in 80mL of ethanol (volume ratio: ethanol:deionized water 1:1). Add 0.5000g of tetrabutyl titanate dropwise to the solution. Stir for 20 minutes, then add 4.0000g of urea and continue stirring for 10 minutes. The mixture is then transferred to a reactor and incubated at 120°C for 24 hours. The reaction mixture is centrifuged, rinsed repeatedly with deionized water and anhydrous ethanol, and then dried in a 75°C oven for 12 hours. Finally, grind to obtain ZnTi-LDH powder.

[0039] Step S3, Preparation of MIL-88B(Fe) / ZnTi-LDH Photocatalytic Composite Material: 0.3600 g of MIL-88B(Fe) powder obtained in step S1 and 0.0040 g of ZnTi-LDH powder obtained in step S2 were simultaneously placed in 8 mL of N,N-dimethylformamide. The mixture was first ultrasonicated for 10 minutes, then slowly stirred at 60°C until the solvent was completely evaporated, and then placed in a 120°C oven for 4 hours. The resulting powder was ground to obtain a MIL-88B(Fe) / ZnTi-LDH photocatalytic composite material, which was designated as MZ-10%.

[0040] Example 2: The difference from Example 1 is that 0.2800 g of MIL-88B(Fe) powder obtained in step S1 and 0.1200 g of ZnTi-LDH powder obtained in step S2 were placed in 8 mL of N,N-dimethylformamide. The resulting MIL-88B(Fe) / ZnTi-LDH photocatalytic composite material is designated MZ-30%.

[0041] Example 3: The difference from Example 1 is that 0.2000 g of MIL-88B(Fe) powder obtained in step S1 and 0.2000 g of ZnTi-LDH powder obtained in step S2 were placed in 8 mL of N,N-dimethylformamide. The resulting MIL-88B(Fe) / ZnTi-LDH photocatalytic composite material is designated MZ-50%.

[0042] Reference Figure 1-Figure 3The composite material has excellent degradation performance for tetracycline, and the solution casting method does not destroy the crystal structure of MIL-88B(Fe) and ZnTi-LDH.

[0043] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0044] The above descriptions are only preferred embodiments of the present invention. Any technical solution that achieves the purpose of the present invention by substantially the same means shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a MIL-88B(Fe) / ZnTi-LDH photocatalyst, characterized by: The method comprises the following steps: S1. Preparation of MIL-88B(Fe) powder: By weight, 60-70 parts of ferric chloride hexahydrate, 30-40 parts of terephthalic acid, and 3-4 mL of sodium hydroxide solution were added to 50-80 mL of N,N-dimethylformamide and dissolved in a beaker. The mixture was ultrasonicated for 10-30 min and stirred for 20-40 min. The mixture was then hydroheated in an oven at 100-120°C for 12-16 h, washed, and dried to obtain MIL-88B(Fe) powder. S2. Preparation of ZnTi-LDH powder: Add 30-40 parts by weight of zinc nitrate hexahydrate and 10-20 parts of tetrabutyl titanate to an ethanol solution, stir for 15-20 minutes, then add 50-60 parts of urea, continue stirring for 10-15 minutes, and hydroheat at 100-120°C for 18-24 hours to obtain the desired ZnTi-LDH powder; S3. Preparation of MIL-88B(Fe) / ZnTi-LDH photocatalyst by solution casting: The MIL-88B(Fe) powder obtained in step S1 and the ZnTi-LDH powder obtained in step S2 were simultaneously placed in a beaker containing a specific solvent and ultrasonicated for 10-20 min. The mixture was then slowly stirred at 50-60°C until the solvent was completely evaporated. The mixture was then placed in an oven at 100-150°C for 3-5 h. The obtained powder was ground to obtain a MIL-88B(Fe) / ZnTi-LDH photocatalyst, which was designated as MZ-X. The mass ratio of ZnTi-LDH powder to the total mass of MIL-88B(Fe) and ZnTi-LDH mixed powder is (3~5):10; The MIL-88B(Fe) / ZnTi-LDH photocatalyst constructs a nn-type heterojunction between MIL-88B(Fe) and ZnTi-LDH.

2. The method for preparing a MIL-88B(Fe) / ZnTi-LDH photocatalyst according to claim 1, characterized in that: In step S1, the molar ratio of ferric chloride hexahydrate to terephthalic acid is (0.8-1.2):1, and the solubility of sodium hydroxide is 2-4 mol / L.

3. The method for preparing a MIL-88B(Fe) / ZnTi-LDH photocatalyst according to claim 1, characterized in that: In step S2, the molar ratio of titanium ions to zinc ions is (1-2):5, and 60-80 mL of ethanol solution is added in step S2, wherein the volume ratio of ethanol to deionized water in the ethanol solution is (1-2):

1.

4. The method for preparing a MIL-88B(Fe) / ZnTi-LDH photocatalyst according to claim 1, wherein: The specific solvent in step S3 is N,N-dimethylformamide, and the volume is 5-10 mL.

5. An application of a MIL-88B(Fe) / ZnTi-LDH photocatalyst, characterized by: It also includes a MIL-88B(Fe) / ZnTi-LDH photocatalyst prepared by the preparation method of any one of claims 1 to 4, and the MIL-88B(Fe) / ZnTi-LDH photocatalyst is used in the field of photocatalytic degradation of antibiotics.

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