LDO@MOFs Composite Material, Its Preparation Method and Application

Abstract

The present invention discloses an LDO@MOFs composite material, its preparation method and application. The method prepares composite materials with different functional groups through in-situ generation. The doping of LDO not only enhances the adsorption capacity through interlayer ion exchange, but also its strong ferromagnetism provides great convenience for the separation and regeneration of the material. Compared with the prior art, the advantages are as follows: The LDO@MOFs synthesized in the present invention has a large porosity and a high specific surface area. In addition, this project also modifies by doping different functional groups. By adding LDO, relying on its high specific surface area and ion exchange effect, the adsorption effect is synergistically improved. In addition, the LDO@MOFs composite material prepared in the present invention with strong fluorescence performance has excellent detection ability and can realize sensitive detection of antibiotics in water. Finally, the magnetic composite material greatly simplifies the recycling and detection process of the material and also greatly reduces the recycling cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater pollutant degradation and detection, and relates to a layered trimetallic oxide / fluorescent metal-organic framework composite material, its preparation method and application, specifically an LDO@MOFs composite material, its preparation method and application. Background Technique

[0002] There are potential risks when antibiotics enter the aquatic environment after use. On the one hand, most antibiotics cannot spontaneously degrade in the natural environment, and their concentrations continue to increase during the enrichment process; on the other hand, excessive antibiotics may threaten the entire ecosystem by selecting antibiotic-resistant bacteria or resistance genes. So far, the detection of antibiotics mainly relies on various expensive and complex instruments, such as high-performance liquid chromatography (HPLC), mass spectrometry (MS), Raman spectroscopy (RS), fluorescence detection (FD), capillary electrophoresis (CE), etc. The high cost and cumbersome operation process have seriously hindered the popularization and application of the above methods. At the same time, fluorescence detection has gradually become a popular detection method due to its high selectivity and convenient operation. Currently, the mainstream methods for removing antibiotics mainly include advanced oxidation methods, photocatalytic methods, adsorption methods, biodegradation methods, etc. Among the above removal methods, the adsorption method has unique advantages such as simple operation, low energy consumption, and high efficiency. More ideally, if an antibiotic adsorbent can effectively detect the target substance, it can greatly improve the efficiency and provide new prospects for the design of related materials. Summary of the Invention

[0003] Technical Problem to be Solved: In order to overcome the deficiencies of the prior art and obtain a method capable of simultaneously detecting and removing antibiotics in wastewater, the present invention provides an LDO@MOFs composite material, its preparation method and application.

[0004] Technical Solution: A preparation method of an LDO@MOFs composite material, the method comprising the following steps:

[0005] S1. Prepare a terpyridine ligand

[0006] The terpyridine ligand is 4-phenylterpyridine, 4-methylphenylterpyridine, 4-carboxyphenylterpyridine and / or 4-nitrophenylterpyridine; the preparation methods are respectively:

[0007] 4-phenylterpyridine: Mix benzaldehyde and sodium hydroxide, dissolve with deionized water, add 2-acetylpyridine and ethanol, stir and react, filter the reaction solution to collect the precipitate, wash and dry the precipitate, then add ammonium acetate and ethanol, react in an oil bath, reflux with ventilation, filter, wash and dry to obtain 4-phenylterpyridine;

[0008] 4-Methylphenylterpyridine: p-Tolualdehyde and 2-acetylpyridine were mixed, wetted with ethanol, and sodium hydroxide solution was added dropwise under ice bath conditions for reaction. After the reaction, the solution was filtered and the resulting precipitate was dissolved in ethanol. Sodium hydroxide and ammonia water were added thereto, and after reaction at 60 °C, it was filtered, washed, and dried to obtain 4-methylphenylterpyridine;

[0009] 4-Carboxyphenylterpyridine: p-Carboxybenzaldehyde and 2-acetylpyridine were mixed, wetted with ethanol, and sodium hydroxide solution was added dropwise under ice bath conditions for reaction. Sodium hydroxide and ammonia water were added thereto, and after reaction at 60 °C, it was acidified with glacial acetic acid to pH 3-4, filtered, washed, and dried to obtain 4-carboxyphenylterpyridine;

[0010] 4-Nitrophenylterpyridine: p-Nitrobenzaldehyde was dissolved in ethanol and aqueous sodium hydroxide solution, and then 2-acetylpyridine was slowly added. The reaction was stirred at room temperature or under ice bath conditions. After the reaction, the precipitate was washed alternately with water and ethanol, filtered, and dried to obtain 4-nitrophenylterpyridine;

[0011] S2. Preparation of NiFeCo-LDO

[0012] Nickel nitrate, iron nitrate, and cobalt nitrate were dissolved in deionized water. Sodium hydroxide solution was added dropwise under a nitrogen atmosphere to adjust the pH value of the solution to 10-11. Then, the resulting solution was hydrothermally treated at 60 °C, washed, and dried to obtain the initial product NiFeCo-LDH. The initial product was ground into a fine powder and calcined in a muffle furnace at 500 °C to obtain NiFeCo-LDO;

[0013] S3. Synthesis of LDO@MOFs composite material

[0014] The terpyridine ligand prepared in S1 was added to dichloromethane, mixed with a methanol solution of zinc benzoate, and NiFeCo-LDO prepared in S2 and benzoic acid were added. The reaction was stirred, filtered, washed, and dried to obtain the in-situ generated LDO@MOFs composite material.

[0015] Preferably, in the preparation process of 4-phenylterpyridine in S1, the molar ratio of benzaldehyde, sodium hydroxide, 2-acetylpyridine, and ammonium acetate is 1:2:2:5.

[0016] Preferably, in the preparation process of 4-methylphenylterpyridine in S1, the molar ratio of p-tolualdehyde, sodium hydroxide, ammonia water, and 2-acetylpyridine is 1:3:1:1.

[0017] Preferably, in the preparation process of 4-carboxyphenylterpyridine in S1, the molar ratio of p-carboxybenzaldehyde, sodium hydroxide, ammonia water, and 2-acetylpyridine is 1:3:1:1.

[0018] Preferably, in the preparation process of 4-nitrophenylterpyridine in S1, the molar ratio of p-nitrobenzaldehyde, sodium hydroxide and 2-acetylpyridine is 1:3:1.

[0019] Preferably, in S2, the molar ratio of nickel nitrate, iron nitrate and cobalt nitrate is 1:1:2, and the concentration of the sodium hydroxide solution is 2 mol / L.

[0020] Preferably, in S3, the molar ratio of the terpyridine ligand, NiFeCo-LDO and zinc benzoate is 1:1:1, the molar ratio of dichloromethane and methanol is 1:1, and the molar ratio of benzoic acid and zinc benzoate is 1:1.

[0021] The LDO@MOFs composite material prepared by any of the above methods.

[0022] The application of the above-mentioned LDO@MOFs composite material in detecting and removing antibiotics in water.

[0023] Preferably, the mass ratio of the composite material to the antibiotic is 3:20.

[0024] Among them, the specific method for the LDO@MOFs composite material to detect and remove antibiotics in water is as follows: use a fluorescence spectrophotometer to test the fluorescence intensity of the LDO@MOFs composite material prepared in S3, add it to antibiotic solutions with different concentrations, and use an ultraviolet spectrophotometer to test its initial absorbance. After reacting for 240 min, take the supernatant to test its absorbance, recover the material with a magnet, and test its fluorescence intensity. Compare the changes in absorbance and fluorescence intensity before and after, and calculate the adsorption capacity and fluorescence detection performance according to the formula.

[0025] The principle of the method of the present invention lies in: the present invention obtains LDO@MOFs composites with different functional groups by in-situ generation. Due to the synergistic effect, the composite has good fluorescence detection and removal performance for antibiotics in water. The doping of LDO not only enhances the adsorption capacity through interlayer ion exchange, but its strong ferromagnetism also provides great convenience for the separation and regeneration of the material. This invention provides a basis for the rational topological design of LDO@MOFs composite materials.

[0026] Beneficial effects: The LDO@MOFs synthesized in the present invention has a large porosity and a high specific surface area. In addition, this project also modifies by doping different functional groups. By adding LDO, with its high specific surface area and ion exchange effect, the adsorption effect is synergistically improved. In addition, the LDO@MOFs composite material prepared in the present invention with strong fluorescence performance has excellent detection ability and can realize the sensitive detection of antibiotics in water. Finally, the magnetic composite material greatly simplifies the recovery and detection process of the material and also greatly reduces the recovery cost. Description of the Drawings

[0027] Figure 1 XRD patterns (a) and infrared spectra (b) of NiFeCo-LDH, NiFeCo-LDO, Zn-MOF-COOH, and LDO@Zn-MOF-COOH prepared in Example 1;

[0028] Figure 2 Transmission electron microscope images of NiFeCo-LDO (a), Zn-MOF-COOH (b), and LDO@Zn-MOF-COOH (c-d) prepared in Example 1, and scanning electron microscope images of NiFeCo-LDO (e) and LDO@Zn-MOF-COOH (f);

[0029] Figure 3 Adsorption effect diagrams of LDO@MOFs for sulfadiazine (a), sulfamerazine (b), ciprofloxacin (c), and norfloxacin (d) at different pH values as described in Example 2 and Comparative Example 1;

[0030] Figure 4 Adsorption effect diagrams of LDO@MOFs for sulfadiazine (a), sulfamerazine (b), ciprofloxacin (c), and norfloxacin (d) at different temperatures as described in Example 2 and Comparative Example 2;

[0031] Figure 5 Adsorption effect diagrams of LDO@MOFs for sulfadiazine (a), sulfamerazine (b), ciprofloxacin (c), and norfloxacin (d) at different times as described in Example 2 and Comparative Example 3;

[0032] Figure 6 Detection effect diagrams of LDO@MOFs for sulfadiazine (a), sulfadiazine detection standard curve (b), sulfamerazine detection effect diagram (c), sulfamerazine detection standard curve (d), ciprofloxacin detection effect diagram (e), ciprofloxacin detection standard curve (f), norfloxacin detection effect diagram (g), and norfloxacin detection standard curve (h) at different concentrations as described in Example 3;

[0033] Figure 7 Detection effect diagrams of LDO@MOFs for sulfadiazine (a), sulfamerazine (b), ciprofloxacin (c), and norfloxacin (d) at different pH values as described in Example 3 and Comparative Example 4;

[0034] Figure 8 Detection effect diagrams of LDO@MOFs for sulfadiazine (a), sulfamerazine (b), ciprofloxacin (c), and norfloxacin (d) at different temperatures as described in Example 3 and Comparative Example 5. Detailed implementation manners

[0035] The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and essence of the present invention, modifications and substitutions made to the methods, steps or conditions of the present invention all fall within the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0036] Example 1

[0037] (1) Preparation method of a series of terpyridine ligands, specifically including the following steps:

[0038] Preparation of 4-phenylterpyridine: Add 4.6 - 5 ml of benzaldehyde to a round-bottom flask, weigh 3.6 - 4 g of sodium hydroxide, completely dissolve it with 60 mL of deionized water, add it to the round-bottom flask, dropwise add 60 mL of ethanol and 10 mL of 2-acetylpyridine, and stir and react for 24 hours. Filter and dry, transfer the obtained white solid to a three-necked flask, add 36 - 40 g of ammonium acetate, and add 200 - 300 mL of ethanol, heat in an oil bath to 80 °C, and reflux with ventilation for 24 hours. After the reaction, a yellow suspension is obtained, filter, wash and dry to obtain the final product.

[0039] Preparation of 4-methylphenylterpyridine: Add 4 - 5 g of p-methylbenzaldehyde and 2.4 g of 2-acetylpyridine to a round-bottom flask, moisten with 10 mL of ethanol, and stir in an ice bath. Weigh 2 - 3 g of sodium hydroxide and dissolve it in 100 mL of deionized water, gradually drop it into the round-bottom flask, and react in the ice bath for 24 hours. Dissolve the obtained solid with 150 - 200 mL of ethanol, add 2.5 g of sodium hydroxide and 10 mL of ammonia water thereto, and heat at 60 °C for 24 hours. Filter, wash and dry to obtain the final product.

[0040] Preparation of 4-carboxyphenylterpyridine: Add 4 - 5 g of p-carboxybenzaldehyde and 4 - 5 g of 2-acetylpyridine to a round-bottom flask, moisten with 10 mL of ethanol, and stir in an ice bath. Weigh 2 - 3 g of sodium hydroxide, dissolve it with 100 mL of deionized water, and gradually drop it into the round-bottom flask. React under ice bath conditions for 24 hours, add 100 mL of ethanol and 10 mL of ammonia water to the reaction solution, react at 60 °C for 24 hours, acidify the reaction solution to pH = 3 - 4 with glacial acetic acid, filter, wash and dry to obtain the final product.

[0041] Preparation of 4-nitrophenylterpyridine: Dissolve 2 - 3 g of p-nitrobenzaldehyde with 20 - 30 mL of ethanol and 2% NaOH aqueous solution, slowly add 1 - 2 g of 2-acetylpyridine, stir at room temperature for 1 hour, filter, wash and dry to obtain the final product.

[0042] (2) Preparation of NiFeCo-LDO: NiFeCo-LDO was obtained by calcining NiFeCo-LDH. Briefly, 5.8158 g of nickel nitrate, 8.08 g of iron nitrate, and 11.6412 g of cobalt nitrate were dissolved in 100 mL of deionized water. Under a nitrogen atmosphere, a 2 mol / L NaOH solution was added dropwise at a rate of 800 r / min to adjust the pH of the solution to 10 - 11. Then, the resulting solution was hydrothermally treated at a constant temperature of 60 °C for about 24 hours. The precipitated dark brown LDH was separated from the solution by centrifugation at 8000 rpm for 10 minutes. The precipitate was washed with deionized water until the pH = 7 and then dried in an oven at 60 °C until the product NiFeCo-LDH was obtained. The obtained NiFeCo-LDH was ground into a fine powder and calcined in a muffle furnace at 500 °C for 8 hours to obtain NiFeCo-LDO.

[0043] (3) Synthesis of LDO@MOFs: LDO was embedded on the surface of in-situ generated Zn-MOFs. 0.15 g of the terpyridine ligand obtained in step (1) was added to 5 mL of dichloromethane to obtain a dichloromethane solution of the ligand, which was mixed with a methanol solution of zinc benzoate (0.15 g / 5 mL). 0.15 g of NiFeCo-LDO prepared in step (2) and 0.15 g of benzoic acid were added, and the mixture was stirred and reacted for 24 hours. After filtration, washing, and drying, the in-situ generated LDO@MOFs material was obtained.

[0044] The prepared NiFeCo-LDO, Zn-MOF-COOH, and LDO@Zn-MOF-COOH were characterized by infrared and XRD, as Figure 1 (a) shows. It can be seen that the characteristic diffraction peak crystal forms of LDH, LDO, and Zn-MOFs are good, and the corresponding positions are consistent with the literature, indicating the successful synthesis of the above materials. The XRD pattern of LDO@Zn-MOF-COOH shows characteristic peaks similar to those of LDO and Zn-MOF-COOH, indicating the successful combination of the two. In addition, the characteristic peaks of LDH corresponding to the (003) and (006) crystal planes reappear in LDO@Zn-MOF-COOH, which may be due to the "memory effect" of LDH under hydrothermal conditions, and LDO is partially reduced to LDH. The FTIR spectra of LDO, Zn-MOF-COOH, and LDO@Zn-MOF-COOH are as Figure 1 (b) shows. These spectra include the stretching vibration peaks of pyridine at 1620 cm -1 , 1580 cm -1 and 1475 cm -1 , as well as the out-of-plane bending vibration peak of the benzene ring at 763 cm-1. And LDO@Zn-MOF-COOH has a peak at 2500 cm -1~3500 cm -1 showed a broad absorption band at this position, which may be due to the symmetric stretching of carboxyl groups, indicating the successful preparation of the composite material.

[0045] Figure 2 are the TEM images and SEM images of NiFeCo-LDO, Zn-MOF-COOH, and LDO@Zn-MOF-COOH, as Figure 2 (a) and Figure 2 (b) show. The TEM images show that Zn-MOF-COOH has a rod-like morphology with a length of 2 μm, and LDO is hexagonal nanosheets with uniform size. In the sample of LDO@MOF-COOH, as Figure 2 (c) and (d) show, we observed that LDO particles with a size of about 100 nm are uniformly supported on the surface of rod-like MOF. The SEM results further confirm the morphology of LDO@MOF-COOH, as Figure 2 (e) and (f) show.

[0046] Example 2

[0047] Method for removing antibiotics from wastewater by layered trimetal oxide / fluorescent metal-organic framework composite material: First, prepare typical antibiotic standard solutions with different concentrations (1, 5, ¹0, 15, 20, 25, 30, 40, and 50 mg / L) respectively. Weigh 3.0 mg of the pre-prepared material (LDO@MOF, LDO@MOF-CH3, LDO@MOF-COOH, or LDO@MOF-NO2) and put it into a beaker containing 30 ml of antibiotic solution. Oscillate at room temperature for 240 minutes, then centrifuge and measure the remaining concentration in the supernatant with an ultraviolet spectrophotometer. The adsorption capacity is calculated by the following formula.

[0048]

[0049] In the formula, q t (mg / g) is the adsorption amount at time point t, C0 (mg / L) and C t are the initial concentration of the antibiotic solution and the concentration of the supernatant at time point t, respectively. V (ml) is the volume of the antibiotic solution, and m (mg) is the mass of the adsorbent.

[0050] Comparative Example 1

[0051] was basically the same as the method, except that the concentration of the selected antibiotic solution was 30 mg / L, and the concentration of the antibiotic was adjusted by adding hydrochloric acid or sodium hydroxide buffer solution. Adsorption experiments were carried out at pH = 4, 5, 6, 7, 8, 9 respectively. The adsorption amounts of different materials for four antibiotics under the above pH conditions are as Figure 3As shown, taking the adsorption of sulfadiazine by LDO@Zn-MOF-COOH as an example, its adsorption capacity increases in the range of pH 4.0 - 6.0 and decreases in the range of pH 6.0 - 9.0, and the adsorption capacity is the largest at pH = 6.0. This may be the result of the electrostatic interaction between the antibiotic and the adsorbent. Similarly, the optimal adsorption pH values of LDO@Zn-MOF, LDO@Zn-MOF-CH3, and LDO@Zn-MOF-NO2 for antibiotics are 7.0, 8.0, and 8.0 respectively.

[0052] Comparative Example 2

[0053] It is basically the same as the method, except that the concentration of the selected antibiotic solution is 30 mg / L, and the adsorption experiments are carried out at temperatures of 20°C, 25°C, 30°C, 35°C, and 40°C respectively. The adsorption capacities of different materials for the four antibiotics under the above temperature conditions are as Figure 4 shown. Taking the adsorption of sulfadiazine by LDO@Zn-MOF-COOH as an example, when the experimental temperature is lower than 45°C, the total adsorption capacity increases with the increase of temperature, and when it is higher than 45°C, the total adsorption capacity decreases. This may be the result of π-π interaction and hydrogen bond binding. Similarly, the optimal adsorption temperatures of LDO@Zn-MOF, LDO@Zn-MOF-CH3, and LDO@Zn-MOF-NO2 are 35°C, 30°C, and 35°C respectively.

[0054] Comparative Example 3

[0055] It is basically the same as the method, except that the concentration of the selected antibiotic solution is 30 mg / L, and samples are taken at times of 0, 1, 5, 10, 20, 30, 60, 90, 120, 150, 180, and 240 min respectively, and the concentration of the supernatant is measured. The adsorption capacities of different materials for the four antibiotics under the above pH conditions are as Figure 5 shown. Taking the adsorption of sulfadiazine as an example, at the beginning of adsorption, with the increase of adsorption time, the adsorption capacities of various adsorbents increase sharply. The adsorption capacities of LDO@Zn-MOF-COOH and LDO@Zn-MOF-NO2 reach equilibrium after 60 and 90 min respectively, and the adsorption time of LDO@Zn-MOF-CH3 and LDO@Zn-MOF is 120 min. It shows that LDO@Zn-MOF-COOH and LDO@Zn-MOF-NO2 have a faster adsorption rate and higher efficiency for antibiotics, and the adsorption capacity is significantly improved after functional group modification.

[0056] Example 3

[0057] Method for detecting antibiotics in wastewater by layered trimetal oxide / fluorescent metal-organic framework composite material:

[0058] Weigh 3 mg of the prepared LDO@MOFs material, measure its fluorescence intensity I0 using a fluorescence spectrophotometer, and place it in a beaker containing 30 ml of antibiotic solutions with different concentrations (1, 5, 10, 15, 20, 25, 30, 40, and 50 mg / L). Place it on a shaker at room temperature for 240 minutes, separate it, and measure its fluorescence intensity I. Calculate the quenching efficiency according to the following Stern-Volmer equation (Equation 2):

[0059] I0 / I = 1 + K sv [c](2)

[0060] In the formula, I0 is the fluorescence intensity at time point 0, I is the fluorescence concentration at time point t, [c] is the initial concentration of the antibiotic solution, and K sv is the fluorescence quenching constant.

[0061] The fluorescence quenching efficiencies of different materials for different antibiotics were tested. As Figure 6 shown, in the low concentration range (0.1 - 50 mg / L), the I0 / I - 1 of LDO@Zn-MOFs shows a linear relationship with the antibiotic concentration. However, as the concentration continues to increase, a linear shift phenomenon occurs, which may be the result of energy transfer, charge transfer between the antibiotic and LDO@Zn-MOFs, and the self-absorption of LDO@Zn-MOFs. The above various influencing factors make the s-v curve change linearly in the low concentration range and non-linearly in the high concentration range. The quenching constants of each antibiotic were obtained through fitting calculations. LDO@Zn-MOF-COOH shows the best quenching efficiency, probably due to the combination of electron transfer and resonance energy transfer. In addition, its strong adsorption ability for antibiotics and good enrichment effect on antibiotics may also be one of the factors affecting the detection effect.

[0062] Comparative Example 4

[0063] The method is basically the same as that in Example 3, except that the concentration of the selected antibiotic solution is 20 mg / L, and the concentration of the antibiotic is adjusted by adding hydrochloric acid or sodium hydroxide buffer solution, and the fluorescence quenching experiments are carried out at pH = 4, 5, 6, 7, 8, 9 respectively. The quenching efficiencies of different materials for the four antibiotics under the above pH conditions are as Figure 7 shown. The optimal detection pH values of the four materials for antibiotics are 6.0, 7.0, 8.0, 8.0 respectively. This may be due to the combined effect of internal electron transfer and adsorption preconcentration.

[0064] Comparative Example 5

[0065] Basically the same as the method of Example 3, except that the concentration of the selected antibiotic solution is 30 mg / L, and the fluorescence quenching experiments are carried out at temperatures of 20 °C, 25 °C, 30 °C, 35 °C, and 40 °C respectively. The quenching efficiencies of different materials for the four antibiotics under the above temperature conditions are as Figure 8 shown. The optimum detection temperatures of the four materials for the antibiotics are 30 °C, 30 °C, 30 °C, and 30 °C respectively.

Claims

1. Preparation method of LDO@MOFs composite material, characterized in that, The method includes the following steps: S1. Prepare terpyridine ligands The terpyridine ligands are 4-phenylterpyridine, 4-methylphenylterpyridine, 4-carboxyphenylterpyridine, and / or 4-nitrophenylterpyridine; the preparation methods are as follows: 4-phenylterpyridine: Mix benzaldehyde and sodium hydroxide, dissolve with deionized water, add 2-acetylpyridine and ethanol, stir and react, filter the reaction solution to collect the precipitate, wash and dry the precipitate, then add ammonium acetate and ethanol, react in an oil bath, reflux with ventilation, filter, wash and dry to obtain 4-phenylterpyridine; 4-methylphenylterpyridine: Mix p-methylbenzaldehyde and 2-acetylpyridine, moisten with ethanol, dropwise add sodium hydroxide solution under ice bath conditions to react, filter the solution after reaction and dissolve the obtained precipitate with ethanol, add sodium hydroxide and ammonia water thereto, react at 60 °C, filter, wash and dry to obtain 4-methylphenylterpyridine; 4-carboxyphenylterpyridine: Mix p-carboxybenzaldehyde and 2-acetylpyridine, moisten with ethanol, dropwise add sodium hydroxide solution under ice bath conditions to react, add sodium hydroxide and ammonia water thereto, react at 60 °C, acidify with glacial acetic acid to pH 3-4, filter, wash and dry to obtain 4-carboxyphenylterpyridine; 4-nitrophenylterpyridine: Dissolve p-nitrobenzaldehyde with ethanol and aqueous sodium hydroxide solution, then slowly add 2-acetylpyridine, stir and react at room temperature or ice bath, wash the precipitate alternately with water and ethanol after reaction, filter and dry to obtain 4-nitrophenylterpyridine; S2. Prepare NiFeCo-LDO Dissolve nickel nitrate, iron nitrate and cobalt nitrate in deionized water, dropwise add sodium hydroxide solution under a nitrogen atmosphere, adjust the pH value of the solution to 10-11, then hydrothermally treat the obtained solution at 60 °C, wash and dry to obtain the initial product NiFeCo-LDH, grind the initial product into fine powder, and calcine in a muffle furnace at 500 °C to obtain NiFeCo-LDO; S3. Synthesize LDO@MOFs composite material Add the terpyridine ligand prepared in S1 to dichloromethane, mix with a methanol solution of zinc benzoate, add the NiFeCo-LDO prepared in S2 and benzoic acid, stir and react, filter, wash and dry to obtain the in-situ generated LDO@MOFs composite material.

2. The preparation method of the LDO@MOFs composite material according to claim 1, wherein, In the preparation process of 4-phenylterpyridine in S1, the molar ratio of benzaldehyde, sodium hydroxide, 2-acetylpyridine and ammonium acetate is 1:2:2:

5.

3. The preparation method of the LDO@MOFs composite material according to claim 1, characterized in that, In the preparation process of 4-methylphenylterpyridine in S1, the molar ratio of p-methylbenzaldehyde, sodium hydroxide, ammonia water and 2-acetylpyridine is 1:3:1:

1.

4. The preparation method of the LDO@MOFs composite material according to claim 1, characterized in that, In the preparation process of 4-carboxyphenylterpyridine in S1, the molar ratio of p-carboxybenzaldehyde, sodium hydroxide, ammonia water and 2-acetylpyridine is 1:3:1:

1.

5. The preparation method of the LDO@MOFs composite material according to claim 1, wherein, In the preparation process of 4-nitrophenylterpyridine in S1, the molar ratio of p-nitrobenzaldehyde, sodium hydroxide and 2-acetylpyridine is 1:3:

1.

6. The preparation method of the LDO@MOFs composite material according to claim 1, characterized in that, In S2, the molar ratio of nickel nitrate, iron nitrate and cobalt nitrate is 1:1:2, and the concentration of the sodium hydroxide solution is 2 mol / L.

7. The preparation method of the LDO@MOFs composite material according to claim 1, characterized in that, In S3, the molar ratio of the terpyridine ligand, NiFeCo-LDO, and zinc benzoate is 1:1:1, the ratio of dichloromethane to methanol is 1:1, and the molar ratio of benzoic acid to zinc benzoate is 1:

1.

8. The LDO@MOFs composite material prepared by the method according to any one of claims 1-7.

9. Use of the LDO@MOFs composite material according to claim 8 in detecting and removing antibiotics in water.

10. The application according to claim 9, wherein The mass ratio of the composite material to the antibiotic is 3:20.

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