Flower-shaped ZnO / ZIF-8 material as well as preparation method and application thereof

Abstract

The invention discloses a flower-shaped ZnO / ZIF-8 material as well as a preparation method and application thereof, and belongs to the technical field of chemical and environmental analysis. The preparation method of the flower-like ZnO / ZIF-8 material comprises the following steps: (1) uniformly mixing a zinc source, urea and a morphology regulator in a solvent to obtain a mixed solution; then sequentially carrying out hydrothermal reaction, centrifugation and roasting treatment to obtain flower-shaped ZnO; (2) mixing and reacting the flower-shaped ZnO with an alcoholic solution of 2-methylimidazole to obtain the flower-shaped ZnO / ZIF-8 material. The dispersive solid-phase extraction technology constructed by the ZnO / ZIF-8 material disclosed by the invention shows high adsorption performance in bisphenol pollutant removal, shows excellent sensitivity and anti-interference capability in detection, and has potential application value in removal and purification or detection of environmental organic pollutants by utilizing chromatography.

Description

Technical Field

[0001] The invention belongs to the technical field of chemistry and environmental analysis, and in particular relates to a flower-shaped ZnO / ZIF-8 material and a preparation method and application thereof. Background Art

[0002] Metal organic frameworks (MOFs), as a new type of crystalline porous material, have attracted extensive attention in the field of adsorption due to their adjustable pore size, clear geometric structure, simple synthesis, and significant specific surface area. However, the limited binding sites of pure MOF restrict its large-scale application. Therefore, several methods have been developed to increase the performance of original MOF materials, including modifying functional groups and compounding with other materials. Among them, composite materials composed of metal oxides as the core and MOF as the outer layer material have been widely studied because they can combine the advantages of metal oxides and MOFs and provide unique physicochemical properties.

[0003] It is well known that the structure and morphology of materials affect their performance to a certain extent. Materials with the same composition but different morphologies show quite different performances. Compared with spherical materials, materials with unique flower-like morphology have greater specific surface area, can provide more recognition sites and are more convenient for mass transfer, and have great potential in the field of separation and enrichment. In view of the unique properties given to the materials by the flower-like morphology and the many advantages of metal oxide / metal organic framework materials (MO / MOF) themselves, it is of great research significance to prepare ZnO / ZIF-8 with special morphology to provide better enrichment performance for analytes. However, the current research on flower-like structures is basically focused on single materials such as oxides, hydroxides, sulfides, and MOFs, and there are no reports on research on flower-like MO / MOF materials and their properties. Summary of the invention

[0004] In view of the above technical problems, the present invention proposes a flower-shaped ZnO / ZIF-8 material and a preparation method and application thereof.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention:

[0007] A method for preparing a flower-shaped ZnO / ZIF-8 material comprises the following steps:

[0008] (1) mixing a zinc source, urea and a morphology modifier in a solvent to obtain a mixed solution; then sequentially performing a hydrothermal reaction, centrifugation and calcination to obtain flower-shaped ZnO;

[0009] (2) The flower-shaped ZnO is mixed with an alcohol solution of 2-methylimidazole and reacted to obtain a flower-shaped ZnO / ZIF-8 material.

[0010] Optionally, the morphology regulator is trisodium citrate.

[0011] Optionally, in the mixed solution of step (1), the concentration of the zinc source is 0.02-0.08 mol / L, the concentration of the urea is 0.04-0.16 mol / L, and the concentration of the trisodium citrate is 2-8 mmol / L.

[0012] Furthermore, the zinc source is zinc acetate.

[0013] Optionally, the hydrothermal reaction conditions are: reacting at 120° C. for 5-8 hours.

[0014] Optionally, the conditions during the roasting process are:

[0015] The temperature was raised to 250-350°C at a heating rate of 1-3°C / min, and then kept at this temperature for 1.5-3h.

[0016] Optionally, the mass ratio of the flower-shaped ZnO to 2-methylimidazole in step (2) is: 0.05:(1-5). Further, the mass ratio is preferably 0.05:1, 0.05:2, 0.05:3, 0.05:4, 0.05:5; more preferably 0.05:2.

[0017] Optionally, the reaction conditions in step (2) are: reacting at room temperature for 5 min-40 min. Further, the reaction time is preferably 5 min, 10 min, 15 min, 20 min, 30 min, 40 min; more preferably 20 min.

[0018] The second technical solution of the present invention:

[0019] The flower-shaped ZnO / ZIF-8 material prepared by the above preparation method.

[0020] The third technical solution of the present invention:

[0021] The above flower-shaped ZnO / ZIF-8 material is used in the removal and enrichment, separation and detection of trace environmental pollutants.

[0022] Optionally, the environmental pollutants are pesticide residues and endocrine disruptors.

[0023] Optionally, the environmental pollutants are bisphenol pollutants; more preferably, they are bisphenol F, bisphenol A, bisphenol B, and bisphenol AF.

[0024] The fourth technical solution of the present invention:

[0025] Application of the above flower-shaped ZnO / ZIF-8 material as a solid phase extraction material.

[0026] Compared with the prior art, the present invention has the following advantages and technical effects:

[0027] The flower-shaped ZnO / ZIF-8 material provided by the present invention has a unique flower-shaped structure (i.e., the petals are sealed together at the mouth, similar to a honeycomb structure), which can provide a channel for rapid mass transfer for the target and shorten the pretreatment time; and the petals have a relatively large surface area, which can expose more active sites, increase the affinity of the material for the target, further improve the sensitivity of the sample pretreatment method and more effectively remove pollutants; the metal oxide (ZnO) core and the outer layer converted MOF (ZIF-8) of the present invention show better synergistic effects on the target.

[0028] The preparation method provided by the present invention can be used to prepare ZnO / ZIF-8 materials with different structures and properties according to the physicochemical properties and structural characteristics of the target object by changing the addition amount of the organic linker and the reaction time, and the preparation process is simple and easy to operate.

[0029] The solid phase extraction technology constructed by the ZnO / ZIF-8 material provided by the present invention exhibits excellent sensitivity and anti-interference ability in the detection of bisphenol compounds (BPs), and has potential application value in the detection or adsorption removal of environmental organic pollutants by chromatography. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings constituting a part of the present invention are used to provide a further understanding 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 an improper limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 The SEM and TEM images of the flower-shaped ZnO and flower-shaped ZnO / ZIF-8 products obtained in Example 1;

[0032] Figure 2 The infrared image (a), XRD image (b), thermogravimetric image (c), and N 2 Adsorption-desorption isotherms (d);

[0033] Figure 3 The figure is a comparison of the adsorption effects of materials (a) prepared with different reaction times and materials (b) prepared with different addition amounts of 2-methylimidazole on bisphenol in Examples 1-10;

[0034] Figure 4 Optimization diagram of the effects of adsorbent mass (a), extraction time (b), desorbent volume (c) and desorption time (d) on BPs peak area;

[0035] Figure 5 It is a comparison chart of the BPs enrichment performance of the flower-shaped ZnO / ZIF-8 prepared in Example 1 and the spherical ZnO / ZIF-8 prepared in Comparative Example 1;

[0036] Figure 6 The adsorption isotherm (a), Langmuir model (b) and Freundlich model (c) of flower-shaped ZnO / ZIF-8 prepared in Example 1 on BPs;

[0037] Figure 7 This is the liquid chromatogram of the flower-shaped ZnO / ZIF-8 prepared in Example 1 when detecting BPs. DETAILED DESCRIPTION

[0038] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0039] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0040] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0041] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0042] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0043] The present invention discloses a method for preparing a ZnO / ZIF-8 material with a unique flower-like structure, and evaluates the application of the synthesized material in enriching and removing trace environmental pollutants. The solid phase extraction technology constructed with ZnO / ZIF-8 material shows high adsorption performance in the removal of bisphenol pollutants and excellent sensitivity and anti-interference ability in the detection of bisphenol compounds, providing a new idea for promoting the application of heterojunction materials in the detection of environmental organic pollutants.

[0044] The embodiment of the present invention discloses a method for preparing a flower-shaped ZnO / ZIF-8 material, comprising the following steps:

[0045] (1) Preparation of flower-like ZnO: zinc acetate and urea are mixed in a solvent, a morphology regulator is added, a solid product is separated by centrifugation after a hydrothermal reaction, and the obtained solid product is calcined in an air atmosphere to obtain the flower-like ZnO;

[0046] (2) Preparation of flower-shaped ZnO / ZIF-8 material: A solution containing the flower-shaped ZnO and a solution containing an organic linker are mixed, and the flower-shaped ZnO / ZIF-8 material is obtained after reaction.

[0047] In some optional embodiments, in step (1): the solvent is ultrapure water, the concentration of zinc acetate is 0.02-0.08 mol / L, the concentration of urea is 0.04-0.16 mol / L, and the concentration of citric acid is 2-8 mmol / L.

[0048] In some optional embodiments, in step (1): the reaction temperature is 120°C and the reaction time is 5-8h.

[0049] In some optional embodiments, in step (1), the calcination is performed by heating the temperature to 250-350° C. at a heating rate of 1-3° C. / min and then keeping the temperature for 1.5-3 h.

[0050] In some alternative embodiments, the organic linker is 2-methylimidazole.

[0051] In some optional embodiments, in step (2): the solvent in the solution is methanol; the reaction temperature is room temperature, and the reaction time is 5-40 min; after the reaction is completed, the product is washed, and the washing is performed 3 times with ethanol.

[0052] In addition, the present invention also provides a flower-shaped ZnO / ZIF-8 material obtained according to the above preparation method.

[0053] The above flower-shaped ZnO / ZIF-8 material is used in the removal and enrichment, separation and detection of trace environmental pollutants.

[0054] In some optional embodiments, the environmental pollutants are pesticide residues, endocrine disruptors and other substances.

[0055] In some optional embodiments, the environmental pollutant is a bisphenol pollutant.

[0056] Application of the above flower-shaped ZnO / ZIF-8 material as a solid phase extraction material.

[0057] The "room temperature" in the present invention refers to 20-30°C unless otherwise specified.

[0058] The raw materials used in the present invention are all purchased from the market.

[0059] The technical solution of the present invention is further illustrated by the following embodiments.

[0060] Example 1

[0061] A method for preparing a flower-shaped ZnO / ZIF-8 material comprises the following steps:

[0062] (1) Preparation of flower-shaped ZnO:

[0063] 3mmol zinc acetate, 6mmol urea, and 0.3mmol trisodium citrate were added to 75mL ultrapure water in sequence to form a clear solution under ultrasound, and then transferred to a 100mL reactor to react at 120°C for 6h, and the solid product was separated by centrifugation, and then washed with ultrapure water and anhydrous ethanol, and then the washed solid material was dried in a 60°C vacuum drying oven to obtain zinc hydroxide carbonate precursor; the dried solid product was heated to 300°C at a rate of 2°C / min in an air atmosphere and kept warm for 2h to obtain flower-like ZnO. Among them, the electron microscope image of flower-like ZnO is shown in Figure 1 (a) and (c);

[0064] (2) Preparation of flower-shaped ZnO / ZIF-8 materials:

[0065] 2g of 2-methylimidazole was added to 13.5mL of methanol and ultrasonically dissolved into a clear solution. 0.05g of flower-shaped ZnO was added to the above methanol solution and ultrasonically formed into a uniform suspension. The mixture was allowed to stand at room temperature for 20min, and the precipitate was collected by centrifugation. The precipitate was washed with water (50mL×3) and ethanol (50mL×3) in sequence. The obtained powder was vacuum dried at 60°C to obtain the flower-shaped ZnO / ZIF-8 (20min) material. The electron microscope image of the flower-shaped ZnO / ZIF-8 is shown in Figure 1 (b) and (d) of .

[0066] Example 2

[0067] The difference from Example 1 is that the standing time at room temperature in step (2) is 5 minutes, and the other conditions are the same as those in Example 1; the obtained flower-shaped ZnO / ZIF-8 (5min) material.

[0068] Example 3

[0069] The difference from Example 1 is that the standing time at room temperature in step (2) is 10 min, and the other conditions are the same as those in Example 1; the obtained flower-shaped ZnO / ZIF-8 (10 min) material.

[0070] Example 4

[0071] The difference from Example 1 is that the standing time at room temperature in step (2) is 15 min, and the other conditions are the same as those in Example 1; the obtained flower-shaped ZnO / ZIF-8 (15 min) material.

[0072] Example 5

[0073] The difference from Example 1 is that the standing time at room temperature in step (2) is 30 min, and the other conditions are the same as those in Example 1; the obtained flower-shaped ZnO / ZIF-8 (30 min) material.

[0074] Example 6

[0075] The difference from Example 1 is that the standing time at room temperature in step (2) is 40 min, and the other conditions are the same as those in Example 1; the obtained flower-shaped ZnO / ZIF-8 (40 min) material.

[0076] Example 7

[0077] The difference from Example 1 is that the amount of 2-methylimidazole added in step (2) is 1 g, and the other conditions are consistent with Example 1; the obtained flower-shaped ZnO / ZIF-8 (1 g) material.

[0078] Example 8

[0079] The difference from Example 1 is that the amount of 2-methylimidazole added in step (2) is 3 g, and the other conditions are the same as those in Example 1; the obtained flower-shaped ZnO / ZIF-8 (3 g) material.

[0080] Example 9

[0081] The difference from Example 1 is that the amount of 2-methylimidazole added in step (2) is 4 g, and the other conditions are the same as those in Example 1; the obtained flower-shaped ZnO / ZIF-8 (4 g) material.

[0082] Example 10

[0083] The difference from Example 1 is that the amount of 2-methylimidazole added in step (2) is 5 g, and the other conditions are the same as those in Example 1; the obtained flower-shaped ZnO / ZIF-8 (5 g) material.

[0084] Figure 1 The SEM and TEM images of the flower-shaped ZnO and flower-shaped ZnO / ZIF-8 (20 min) materials prepared in Example 1 are shown in FIG. Figure 1 It can be seen that the flower-like ZnO material and the flower-like ZnO / ZIF-8 (20min) material are spherical and have a large number of flaky petals. The petals have a larger surface area and can expose more active sites. Figure 1 It can be seen from (e)-(h) that the flower-like ZnO / ZIF-8 (20min) material includes four elements: Zn, O, C, and N, and the four elements are evenly distributed. Figure 1 (a) is the SEM image of flower-like ZnO, (b) is the SEM image of flower-like ZnO / ZIF-8, (c) and (d) are TEM images of flower-like ZnO / ZIF-8, and (l) is the energy dispersive X-ray spectrum of flower-like ZnO / ZIF-8. The above results indicate that flower-like ZnO is successfully transformed into flower-like ZnO / ZIF-8.

[0085] Figure 2 The infrared image (a), XRD image (b), thermogravimetric image (c), and N 2 Adsorption-desorption isotherm diagram (d). Figure 2 In the middle (a) infrared image, it can be seen that the flower-shaped ZnO / ZIF-8 spectrum has an obvious imidazole peak; Figure 2 In (b), it can be seen that the flower-shaped ZnO / ZIF-8 XRD pattern shows the characteristic peaks of ZIF-8; Figure 2 In (c), it can be seen that the thermal stability of flower-like ZnO / ZIF-8 decreases; Figure 2 In (d), it can be seen that the specific surface area of ​​flower-like ZnO / ZIF-8 is greatly increased. The above results indicate that flower-like ZnO is successfully transformed into flower-like ZnO / ZIF-8.

[0086] Comparative Example 1

[0087] A method for preparing a spherical ZnO / ZIF-8 material comprises the following steps:

[0088] (a) 5.49 g of zinc acetate dihydrate was added to 250 mL of diethylene glycol and refluxed at 160 °C for 1 h. After the mixture was cooled to room temperature, the white powder was collected by centrifugation and washed with ethanol several times, and dried in vacuum at 60 °C to obtain spherical ZnO;

[0089] (b) 2 g of 2-methylimidazole was added to 13.5 mL of methanol and ultrasonically dissolved into a clear solution. 0.05 g of spherical ZnO was added to the above methanol solution and ultrasonically formed into a uniform suspension. The mixture was allowed to stand at room temperature for 20 min, and the precipitate was collected by centrifugation. The precipitate was washed with water (50 mL×3) and ethanol (50 mL×3) in sequence. The obtained powder was vacuum dried at 60° C. to obtain the spherical ZnO / ZIF-8 material.

[0090] Comparative Example 2

[0091] The difference from Example 1 is that zinc acetate is replaced by an equal amount of ferric chloride. Other conditions are the same as in Example 1.

[0092] In this comparative example, zinc acetate was replaced by an equal amount of ferric chloride, and iron oxide could not be synthesized.

[0093] Effect verification

[0094] (1) In order to select the best synthesis conditions, the following tests were performed on the extraction performance of the materials prepared in Examples 1-10:

[0095] 25 mg of the material was added to a solution containing 200 ng mL -1 The 30 mL sample solution was placed in a centrifuge tube and ultrasonicated in a water bath for 3 min to allow the target analyte to be fully adsorbed by the material. After centrifugation, the supernatant was discarded, and the material was transferred to a 5 mL centrifuge tube, centrifuged again to discard the supernatant, and 1 mL of acetonitrile was used to elute the BPs on the adsorbent. After ultrasonication in a water bath for 9 min, the elution was obtained by centrifugation.

[0096] Figure 3 The comparison of the adsorption effect of materials (a) prepared with different reaction times and materials (b) prepared with different 2-methylimidazole additions on bisphenol shows that when the addition amount of 2-methylimidazole is set to 2g and the reaction time is set to 20min, the adsorption capacity of the composite material on bisphenol reaches the best. Therefore, the flower-shaped ZnO / ZIF-8 (20min) material synthesized with a reaction time of 20min and a 2-methylimidazole addition of 2g was selected for subsequent experiments.

[0097] (2) The factors affecting the enrichment performance of the flower-shaped ZnO / ZIF-8 (20 min) adsorbent prepared in Example 1 were optimized by:

[0098] The flower-shaped ZnO / ZIF-8 (20 min) adsorbent (10-30 mg) prepared in Example 1 was added to 30 mL of a mixed standard containing bisphenol compounds (200 ng mL -1) solution in a centrifuge tube. The centrifuge tube was placed in an ultrasonic instrument with a power of 60W and a temperature of 25±2℃ for extraction for a period of time (1-11min). After centrifugation, the supernatant was poured out and the material was transferred to a 5mL centrifuge tube. The BPs on the adsorbent were eluted with a certain volume (0.5-3.0mL) of acetonitrile. After ultrasonic desorption in a water bath for a certain period of time (1-11min), the elution was obtained by centrifugation. After desorption, the eluate was collected by centrifugation and placed in N 2 Finally, the residue was reconstituted in 100 μL ACN, filtered through a 0.22 μm nylon membrane, and subjected to HPLC-DAD analysis.

[0099] Figure 4 This is an optimization diagram of the effects of adsorbent mass (a), extraction time (b), desorbent volume (c) and desorption time (d) on the BPs peak area (n=3, the average value obtained from three repeated experiments); it can be seen from the figure that the optimal adsorbent dose is 25 mg, the optimal extraction time is 3 min, the optimal desorption solution volume is 1 mL, and the optimal desorption time is 9 min.

[0100] (3) In order to verify the enrichment ability of the product obtained in the present invention for trace bisphenol compounds (BPs), the flower-shaped ZnO / ZIF-8 prepared in Example 1 and the product of Comparative Example 1 were subjected to extraction tests. The specific conditions of the extraction were:

[0101] The products of Example 1 and Comparative Example 1 (25 mg) were added to the target compound (200 ng mL -1 , 30mL) of water sample was ultrasonicated for 5min, and then solid-liquid phase separation was performed to obtain a precipitate, and the obtained precipitate was added to 2mL of acetonitrile for ultrasonication (9min) to complete the elution process, the eluted supernatant was dried, and the dried residue was re-dissolved with 80μL of acetonitrile. Finally, 5μL of the re-dissolved sample was taken for detection by high performance liquid chromatography-diode array detector (HPLC-DAD).

[0102] Figure 5The figure is a comparison of the enrichment performance of BPs by the flower-shaped ZnO / ZIF-8 prepared in Example 1 and the spherical ZnO / ZIF-8 prepared in Comparative Example 1. As can be seen from the figure, the enrichment effect of the flower-shaped ZnO / ZIF-8 prepared in Example 1 of the present invention on four BPs, namely bisphenol A (BPA), bisphenol B (BPB), bisphenol AF (BPAF) and bisphenol F (BPF), is higher than that of spherical ZnO / ZIF-8, indicating the potential of the unique flower-shaped ZnO / ZIF-8 prepared in Example 1 of the present invention in separating and enriching BPs. The high extraction performance may be because the flower-shaped morphology can expose more recognition sites to accommodate more targets, increase the affinity of the material for the target, improve the extraction capacity for the target, and help to improve the sensitivity of the sample pretreatment method and more effectively remove pollutants.

[0103] (4) In order to verify the adsorption and removal ability of the product obtained in the present invention on the environmental pollutant bisphenol compounds (BPs), the thermodynamic adsorption performance of the flower-shaped ZnO / ZIF-8 prepared in Example 1 was tested. The specific operation is:

[0104] 5 mg of flower-like ZnO / ZIF-8 was added to a BPs solution containing different concentrations (0-300 mg / L, 5 mL) and ultrasonicated for 3 h to reach adsorption equilibrium. After centrifugation, 1 mL of the sample solution was filtered through a 0.22 μm nylon membrane and analyzed by HPLC-DAD.

[0105] Figure 6 The adsorption isotherms (a), Langmuir model (b) and Freundlich model (c) of flower-like ZnO / ZIF-8 on BPs. Figure 6 As can be seen in (a), the adsorption capacities of flower-like ZnO / ZIF-8 for BPAF, BPA, BPF, and BPB are 408, 381, 364, and 403 mg / g, respectively. That is, the large adsorption capacity of flower-like ZnO / ZIF-8 for BPs is related to the fact that the flower-like structure exposes more adsorption sites.

[0106] (5) In order to verify the anti-interference ability of the product obtained in the present invention, the flower-shaped ZnO / ZIF-8 prepared in Example 1 was subjected to an extraction test. The water sample was taken from a lake in the school. In order to remove possible suspended particles, it was filtered through a 0.22 μm nylon membrane before extraction and stored in a refrigerator at 4°C for HPLC-DAD analysis. The analysis results are shown in FIG. Figure 7 (line a) shows.

[0107] The specific conditions of the detection are: using a ZORBAX SB-C18 (250mm×4.6mm, 5μm) chromatographic column for sample separation, a mixture of acetonitrile (ACN) (A) and water (B) as the mobile phase, and a gradient elution of bisphenols as follows: 0-4min=50-70% A, 4-8min=70-50% A, the detection wavelength is set to 270nm, and the flow rate is set to 1.0mL / min. The injection volume is 5μL, the column temperature is maintained at 25°C, and the flower-shaped ZnO / ZIF-8 is used as the SPE material in conjunction with HPLC-DAD to detect bisphenol environmental pollutants in the environment. The chromatographic analysis is performed on an Agilent 1260HPLC (Agilent Technologies, Santa Clara, California) system equipped with a diode array detector (DAD) to detect the target. The test results are as follows: Figure 7 shown.

[0108] Figure 7 This is the liquid chromatogram of the flower-shaped ZnO / ZIF-8 prepared in Example 1 when detecting BPs. As can be seen from the figure, when the untreated water sample is directly injected, no target substance is detected ( Figure 7 After the water sample was enriched with the prepared flower-like ZnO / ZIF-8, the BPF analyte was detected ( Figure 7 The target was spiked (the target was added to the water sample before filtration to prepare 20 ng mL -1 The aqueous solution is then filtered, enriched, and tested) Figure 7 As shown in the middle c line, where chromatographic peak 1 is bisphenol F, chromatographic peak 2 is bisphenol A, chromatographic peak 3 is bisphenol B, and chromatographic peak 4 is bisphenol AF), the results show that the prepared flower-like ZnO / ZIF-8 has a good detection effect on bisphenol environmental pollutants and can be used for the detection and monitoring of trace pollutants in the environment. Figure 7 It can also be seen that the flower-shaped ZnO / ZIF-8 has good detection performance for bisphenol pollutants and a symmetrical chromatographic peak shape, indicating that the established method is not affected by complex environmental water matrices, has strong anti-interference ability and good selectivity for complex environmental water sample matrices.

[0109] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a flower-shaped ZnO / ZIF-8 material, characterized in that: The following steps are involved: (1) mixing a zinc source, urea and a morphology modifier in a solvent to obtain a mixed solution; then sequentially performing a hydrothermal reaction, centrifugation and calcination to obtain flower-shaped ZnO; (2) The flower-shaped ZnO is mixed with an alcohol solution of 2-methylimidazole to react to obtain a flower-shaped ZnO / ZIF-8 material.

2. The method for preparing a flower-shaped ZnO / ZIF-8 material according to claim 1, characterized in that: The morphology regulator is trisodium citrate.

3. The method for preparing a flower-shaped ZnO / ZIF-8 material according to claim 1, characterized in that: In the mixed solution of step (1), the concentration of the zinc source is 0.02-0.08 mol / L, the concentration of the urea is 0.04-0.16 mol / L, and the concentration of the morphology regulator is 2-8 mmol / L.

4. The method for preparing a flower-shaped ZnO / ZIF-8 material according to claim 1, characterized in that: The conditions of the hydrothermal reaction are: reacting at 120° C. for 5-8 hours; and / or The conditions during the calcination process are: heating the temperature to 250-350° C. at a heating rate of 1-3° C. / min, and then keeping the temperature at this temperature for 1.5-3 hours.

5. The method for preparing a flower-shaped ZnO / ZIF-8 material according to claim 1, characterized in that: The mass ratio of the flower-shaped ZnO to 2-methylimidazole in step (2) is 0.05:(1-5).

6. The method for preparing a flower-shaped ZnO / ZIF-8 material according to claim 5, characterized in that: The reaction conditions in step (2) are: reacting at room temperature for 5 min-40 min.

7. The method for preparing a flower-shaped ZnO / ZIF-8 material according to claim 6, characterized in that: The mass ratio of the flower-shaped ZnO to 2-methylimidazole in step (2) is 0.05:2; and the reaction time is 20 minutes.

8. A flower-shaped ZnO / ZIF-8 material prepared according to the preparation method according to any one of claims 1 to 7.

9. Use of the flower-shaped ZnO / ZIF-8 material as claimed in claim 8 in removing, enriching, separating and detecting trace environmental pollutants.

10. Use of the flower-shaped ZnO / ZIF-8 material as claimed in claim 8 as a solid phase extraction material.

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