Multi-element metal organic framework material containing graded holes as well as preparation method and application of multi-element metal organic framework material

Abstract

The invention discloses a multi-element metal organic framework material containing graded holes as well as a preparation method and application thereof, and relates to the technical field of materials. The multi-element metal organic framework material containing the hierarchical pores is prepared by taking diphenyldicarboxylic acid and functionalized terephthalic acid as organic connectors and zirconium salt as a metal source through solvothermal reaction, the functionalized terephthalic acid is tetrafluoroterephthalic acid, 2-aminoterephthalic acid, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, and 2, 5-diaminoterephthalic acid, 2-hydroxyterephthalic acid, or 2, 5-dihydroxyterephthalic acid. The multi-element metal organic framework material containing the graded holes is prepared by self-assembly of diphenyldicarboxylic acid capable of being coordinated with metal ions, functionalized terephthalic acid and zirconium for providing the metal ions, can enrich environmental pollutant bisphenol compounds with high capacity, and shows excellent reproducibility and reusability; and the preparation process is simple, the cost is low, and the application prospect is good.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to a multi-element metal organic framework material containing hierarchical pores and a preparation method and application thereof. Background Art

[0002] Persistent organic pollutants (POPs) are relatively chemically resistant, can persist for years before decomposing, are globally circulated through evaporation and deposition processes, and are highly bioaccumulative in organic tissues, posing a threat to environmental ecology and biological systems. Bisphenol compounds (BPs), such as bisphenol A (BPA) and its substitutes bisphenol B (BPB), bisphenol F (BPF) and bisphenol AF (BPAF), are endocrine disrupting chemicals and are widely used in the production of thermal paper, medical equipment, toys, electronic products, etc.

[0003] Persistent organic pollutants are ubiquitous in the environment and are currently found in surface water and sediments, and their concentrations are increasing. Toxicological studies have shown that BPs exhibit potential toxic effects on organisms, such as disrupting the endocrine system of humans and other organisms, and are associated with fertility, cardiovascular disease, obesity, allergic diseases, and neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. Therefore, the efficient removal of BPs from the environment and the follow-up detection of residual BPs in the environment after removal are of great significance for protecting the environment and human health.

[0004] At present, there are many materials used for BPs removal or enrichment detection, such as metal organic framework materials (MOFs), covalent organic framework materials (COFs), metal oxides, carbon materials, etc. Among them, MOFs with periodic network structures formed by self-assembly of inorganic metal centers (metal ions or metal clusters) and bridging organic ligands have been favored by scientific researchers due to their large specific surface area, regular pore structure, low price, simple synthesis conditions, large adsorption capacity and good stability. The performance of MOFs in the field of separation and enrichment has also been widely studied. However, the limited action sites and single functional group types of pure MOFs materials limit the large-scale practical application of this material. Multi-component MOFs materials constructed by multiple organic linkers and metal coordination have solved the above problems to a certain extent because they exhibit special physicochemical properties that single-component MOFs do not have. However, most of the multi-component MOFs materials reported so far have a single pore size, while it is reported that multi-level pore structure materials can better "capture" analytes and exhibit higher performance than single pore size materials. Therefore, preparing multi-MOFs materials with a multi-level pore structure to maximize the performance of the materials can provide protection for the environment and the health of organisms. Summary of the invention

[0005] The purpose of the present invention is to provide a multinary metal organic framework material containing hierarchical pores and its preparation method and application, so as to solve the problems existing in the above-mentioned prior art. The multinary metal organic framework material (X-BDC@UiO-67) containing hierarchical pores of the present invention is assembled from biphenyl dicarboxylic acid, functionalized terephthalic acid and zirconium source that provides metal ions, which can enrich environmental pollutant bisphenol compounds with high capacity, and exhibits excellent reproducibility and reusability. Moreover, its preparation process is simple, the cost is low, and it has good application prospects.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is to provide a multi-element metal organic framework material (X-BDC@UiO-67) containing hierarchical pores: using two dicarboxylic acid ligands of different chain lengths, biphenyl dicarboxylic acid and functionalized terephthalic acid as organic linkers, and zirconium salt as a metal source, and preparing the material through a solvent thermal reaction;

[0008] The functionalized terephthalic acid is tetrafluoroterephthalic acid, 2-aminoterephthalic acid, 2,5-diaminoterephthalic acid, 2-hydroxyterephthalic acid or 2,5-dihydroxyterephthalic acid.

[0009] Furthermore, the zirconium salt is zirconium tetrachloride.

[0010] In the present invention, the functionalized terephthalic acid is more preferably tetrafluoroterephthalic acid, and the corresponding multi-metal organic framework material containing hierarchical pores is named 4F-BDC@UiO-67.

[0011] The second technical solution of the present invention is to provide a method for preparing the multi-element metal organic framework material containing hierarchical pores, comprising the following steps:

[0012] The multi-metal organic framework material (X-BDC@UiO-67) containing hierarchical pores is obtained by using biphenyl dicarboxylic acid and functionalized terephthalic acid as organic linkers and zirconium salt as a metal source through a solvent thermal reaction.

[0013] Furthermore, the solvent used in the solvothermal reaction is dimethylformamide.

[0014] Furthermore, a solution buffer is added to the solvent thermal reaction system; the solution buffer is benzoic acid.

[0015] Furthermore, in the solvent thermal reaction system, the concentration of the biphenyl dicarboxylic acid is 4.5-11.5 mM, the concentration of the functionalized terephthalic acid is 2.2-9.2 mM, and the concentration of the zirconium salt is 10-18 mM.

[0016] Furthermore, in the solvothermal reaction system, the concentration of benzoic acid is 0.2-0.8M.

[0017] Furthermore, the temperature of the solvent thermal reaction is 100° C.; the time of the solvent thermal reaction is 20-26 hours.

[0018] Furthermore, before the solvothermal reaction, the method further comprises a step of subjecting the reaction system to ultrasonic treatment; the time of the ultrasonic treatment is preferably 30-60 minutes.

[0019] Furthermore, after the solvothermal reaction is completed, the process further includes steps of washing, centrifuging and drying the product.

[0020] The more preferred preparation steps of the multinary metal organic framework material (X-BDC@UiO-67) containing hierarchical pores of the present invention are as follows: dissolving biphenyl dicarboxylic acid, functionalized terephthalic acid and zirconium tetrachloride in a dimethylformamide solution, ultrasonically treating, adding benzoic acid to the above solution, continuing the ultrasonic treatment, and then placing it in an oven at 100°C for heating; after the reaction is completed, washing the obtained product, centrifuging it, and drying it to obtain the multinary metal organic framework material (X-BDC@UiO-67) containing hierarchical pores.

[0021] The washing is preferably performed by washing with dimethylformamide and ethanol three times in sequence; the centrifugation is preferably performed at a speed of 10,000 rpm for 5 minutes; and the drying is preferably performed by vacuum drying at 80° C. for 6 hours.

[0022] The invention adopts a one-step solvent thermal method to synthesize a multi-element metal organic framework material containing hierarchical pores, has a simple operation process, a simple process and can be prepared in large quantities.

[0023] The third technical solution of the present invention: provides the use of the above-mentioned multi-metal organic framework material containing hierarchical pores in the removal and enrichment of environmental organic pollutants; the organic pollutants are persistent organic pollutants.

[0024] The fourth technical solution of the present invention is to provide the application of the above-mentioned multi-metal organic framework material containing hierarchical pores in the removal and detection of bisphenol pollutants.

[0025] The multi-element metal organic framework material containing hierarchical pores of the present invention can be used as a solid phase extraction material to remove and enrich bisphenol compounds in complex matrices, and can be used in conjunction with a high performance liquid chromatography-diode array detector (HPLC-DAD) to detect its content to evaluate environmental safety.

[0026] The present invention adopts a dual ligand as an organic linker. In a more preferred technical solution, the CF functional group contained in the introduced ligand can act as a hydrogen bond donor and generate hydrogen bond interaction force with the bisphenol compound containing a hydroxyl group. Moreover, since the electron cloud density around the fluorine atom is very high, the fluorine atom in the CF functional group contained in the introduced ligand can form a strong FF interaction with the organic pollutant containing F (such as bisphenol AF, perfluorinated compounds, etc.); by using organic linkers with different sizes as dual ligands, the prepared material has a hierarchical pore structure, provides pores of different sizes, and increases the adsorption sites and surface area; the unsaturated metal sites contained in the material can act as a type of mild Lewis acid site to coordinate the bisphenol compound containing a hydroxyl group. Compared with the original unfunctionalized single-component single-pore UiO-67, the CF functional group in the novel 4F-BDC@UiO-67 of the present invention can be used as a hydrogen bond donor, the newly added unsaturated metal site can be used as a Lewis acid site, and the hierarchical pore structure can expose more active sites to provide additional hydrogen bonds and FF interaction forces, coordination forces and size exclusion effects for the adsorption, removal and separation and enrichment of harmful bisphenol pollutants, which is beneficial to improve the removal performance and the sensitivity of the detection method. Due to this unique property, the MOF with the introduction of CF functional groups and hierarchical pore structures can enrich and adsorb bisphenol pollutants, achieving effective removal and trace detection of bisphenol.

[0027] As an adsorption and enrichment material, the 4F-BDC@UiO-67 of the present invention inherits the excellent properties of single-component MOFs materials and adds functional groups and multi-level pore characteristics. It has multiple advantages such as high specific surface area and porosity, good crystallinity and dispersibility, high stability, simple preparation and easy industrialization. At the same time, the introduction of CF functional groups, hierarchical pore structure and newly added unsaturated metal sites greatly increase the affinity of the material to the target, which is beneficial to improving the enrichment performance.

[0028] The present invention discloses the following technical effects:

[0029] The present invention adopts dual ligands of different chain lengths as organic linkers, and adopts a one-step solution thermal reaction to prepare a multi-element metal organic framework material containing hierarchical pores. The unique hierarchical pore structure contained in the material provides pores of different sizes including micropores and mesopores (micropores can provide action sites, and mesopores can quickly transfer mass), which can increase adsorption sites and surface area; the newly added unsaturated metal sites in the material can be used as a type of mild Lewis acid site to coordinate bisphenol compounds containing hydroxyl groups, greatly improving the adsorption and removal performance of the material and the sensitivity of the detection method; the material is used as an enrichment material for the removal and enrichment of environmental bisphenol pollutants, can enrich environmental pollutant bisphenol compounds with high capacity, and exhibits excellent reproducibility and reusability.

[0030] The preparation process of the present invention is simple, and the obtained multi-metal organic framework material containing hierarchical pores has ultra-high removal capacity and super-good enrichment ability for bisphenol pollutants. Good stability and easy regeneration enable the material to be repeatedly used, greatly reducing costs. It has good application prospects in the fields of detecting and removing bisphenol pollutants in complex environmental matrices, and can provide guarantees for the efficient removal and sensitive detection of bisphenol compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 SEM (a), TEM (b)-(c) and Mapping (dg) images of 4F-BDC@UiO-67 prepared in Example 1.

[0033] Figure 2 These are the SEM images of 16.7% 4F-BDC@UiO-67 prepared in Example 2 (a), the SEM image of 33.3% 4F-BDC@UiO-67 prepared in Example 3 (b), and the SEM image of 66.7% 4F-BDC@UiO-67 prepared in Example 4 (c).

[0034] Figure 3 This is the SEM image of UiO-67 prepared in Comparative Example 1.

[0035] Figure 4 NH prepared in Example 5 2 -BDC@UiO-67 (ab) and SEM images of 2OH-BDC@UiO-67 (cd) prepared in Example 6.

[0036] Figure 5 FT-IR spectra of UiO-67, 16.7% 4F-BDC@UiO-67, 33.3% 4F-BDC@UiO-67, 4F-BDC@UiO-67, 66.7% 4F-BDC@UiO-67 (a); Thermogravimetric analysis of UiO-67 and 4F-BDC@UiO-67 (b), N 2 Adsorption isotherm curve (c) and pore size distribution curve (d).

[0037] Figure 6Thermodynamic adsorption performance of bisphenol by the 4F-BDC@UiO-67 adsorbent prepared in Example 1 is measured, wherein (a) is the adsorption isotherm, (b) is the Langmuir model, and (c) is the Freundlich model.

[0038] Figure 7 This is a comparison chart of the enrichment performance of the multi-metal organic framework material (4F-BDC@UiO-67) adsorbent containing hierarchical pores prepared in Example 1 and UiO-67 prepared in Comparative Example 1 for bisphenol environmental pollutants.

[0039] Figure 8 NH prepared in Example 5 2 Comparison of the enrichment performance of bisphenol environmental pollutants by 2OH-BDC@UiO-67 prepared in Example 6 and UiO-67 prepared in Comparative Example 1.

[0040] Fig. 9 This is a diagram of the reuse performance of 4F-BDC@UiO-67 prepared in Example 1. DETAILED DESCRIPTION

[0041] 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.

[0042] It should be understood that the terms described in the present invention are only for describing a particular embodiment 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. The intermediate value in any stated value or stated range, and each smaller range between 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.

[0043] 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.

[0044] 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.

[0045] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0046] Example 1

[0047] The multinary metal-organic framework material (4F-BDC@UiO-67) containing hierarchical pores is prepared by solvothermal method using tetrafluoroterephthalic acid and biphenyl dicarboxylic acid containing CF functional groups as organic ligands, zirconium tetrachloride as metal source, dimethylformamide as solvent, and benzoic acid as solution buffer; wherein the tetrafluoroterephthalic acid linker contains two carboxyl groups and four CF functional groups, and the biphenyl dicarboxylic acid ligand contains two carboxyl functional groups.

[0048] Preparation of multi-element metal-organic framework materials (4F-BDC@UiO-67) containing hierarchical pores:

[0049] Add biphenyl dicarboxylic acid (0.40 g), tetrafluoroterephthalic acid (0.393 g), and zirconium tetrachloride (0.256 g) to DMF (80 mL), and ultrasonicate for 1 h to obtain a clear and transparent solution. Add 5.3 g of benzoic acid to the above solution, ultrasonicate vigorously for 1 h (60 W), and then transfer to a reactor and place it in an oven preheated to 100 ° C for 24 h. After the reaction is completed, the obtained product is washed alternately with dimethylformamide and ethanol for 3 times, centrifuged at a speed of 10000 rpm for 3 min, and the obtained product is vacuum dried at 80 ° C for 6 h to obtain 4F-BDC@UiO-67.

[0050] Example 2

[0051] Preparation of 16.7% 4F-BDC@UiO-67:

[0052] Add biphenyl dicarboxylic acid (0.67 g), tetrafluoroterephthalic acid compound (0.131 g), zirconium tetrachloride (0.256 g) to DMF (80 mL), and ultrasonicate for 1 h to obtain a clear and transparent solution. Add 5.3 g of benzoic acid to the above solution, ultrasonicate vigorously for 1 h (60 W), and then transfer to a reactor and place it in an oven preheated to 100 ° C to react for 24 h. After the reaction is completed, the obtained product is washed alternately with dimethylformamide and ethanol for 3 times, centrifuged at a speed of 10000 rpm for 3 min, and the obtained product is vacuum dried at 80 ° C for 6 h to obtain 16.7% 4F-BDC@UiO-67.

[0053] Example 3

[0054] Preparation of 33.3% 4F-BDC@UiO-67:

[0055] Add biphenyl dicarboxylic acid (0.53 g), tetrafluoroterephthalic acid (0.262 g), and zirconium tetrachloride (0.256 g) to DMF (80 mL), and ultrasonicate for 1 h to obtain a clear and transparent solution. Add 5.3 g of benzoic acid to the above solution, ultrasonicate vigorously for 1 h (60 W), and then transfer to a reactor and place it in an oven preheated to 100 ° C for 24 h. After the reaction is completed, the obtained product is washed alternately with dimethylformamide and ethanol for 3 times, centrifuged at 10000 rpm for 3 min, and the obtained product is vacuum dried at 80 ° C for 6 h to obtain 33.3% 4F-BDC@UiO-67.

[0056] Example 4

[0057] Preparation of 66.7% 4F-BDC@UiO-67

[0058] Add biphenyl dicarboxylic acid (0.266g), tetrafluoroterephthalic acid (0.524g), and zirconium tetrachloride (0.256g) to DMF (80mL), and obtain a clear and transparent solution after ultrasonic treatment for 1h. Add 5.3g of benzoic acid to the above solution, vigorously ultrasonicate for 1h (60W), and then transfer to a reactor and place it in an oven preheated to 100°C for reaction for 24h. After the reaction is completed, the obtained product is washed alternately with dimethylformamide and ethanol for 3 times, centrifuged at a speed of 10000rpm for 3min, and the obtained product is vacuum dried at 80°C for 6h to obtain 66.7% 4F-BDC@UiO-67.

[0059] Example 5

[0060] NH 2 Preparation of -BDC@UiO-67

[0061] Add biphenyl dicarboxylic acid (0.40 g), 2-aminoterephthalic acid (0.299 g), and zirconium tetrachloride (0.256 g) to DMF (80 mL), and ultrasonicate for 1 h to obtain a clear and transparent solution. Add 5.3 g of benzoic acid to the above solution, ultrasonicate vigorously for 1 h (60 W), and then transfer to a reactor and place in an oven preheated to 100 ° C to react for 24 h. After the reaction is completed, the obtained product is washed alternately with dimethylformamide and ethanol for 3 times, centrifuged at a speed of 10000 rpm for 3 min, and the obtained product is vacuum dried at 80 ° C for 6 h to obtain NH 2 -BDC@UiO-67.

[0062] Example 6

[0063] Preparation of 2OH-BDC@UiO-67

[0064] Add biphenyl dicarboxylic acid (0.40 g), 2,5-dihydroxyterephthalic acid (0.327 g), and zirconium tetrachloride (0.256 g) to DMF (80 mL), and obtain a clear and transparent solution after ultrasonic treatment for 1 h. Add 5.3 g of benzoic acid to the above solution, vigorously ultrasonicate for 1 h (60 W), and then transfer to a reactor and place it in an oven preheated to 100 ° C for 24 h. After the reaction is completed, the obtained product is washed alternately with dimethylformamide and ethanol for 3 times, centrifuged at a speed of 10000 rpm for 3 min, and the obtained product is vacuum dried at 80 ° C for 6 h to obtain 2OH-BDC@UiO-67.

[0065] Comparative Example 1

[0066] Preparation of UiO-67

[0067] Add biphenyl dicarboxylic acid (0.8 g) and zirconium tetrachloride (0.256 g) to DMF (80 mL), and ultrasonicate for 1 h to obtain a clear and transparent solution. Add 5.3 g of benzoic acid to the above solution, ultrasonicate vigorously for 1 h (60 W), and then transfer to a reactor and place in an oven preheated to 100 ° C to react for 24 h. After the reaction is completed, the obtained product is washed alternately with dimethylformamide and ethanol for 3 times, centrifuged at a speed of 10000 rpm for 3 min, and the obtained product is vacuum dried at 80 ° C for 6 h to obtain UiO-67.

[0068] Figure 1 SEM (a), TEM (b)-(c) and Mapping (dg) images of 4F-BDC@UiO-67 prepared in Example 1.

[0069] Figure 2These are the SEM images of 16.7% 4F-BDC@UiO-67 prepared in Example 2 (a), the SEM image of 33.3% 4F-BDC@UiO-67 prepared in Example 3 (b), and the SEM image of 66.7% 4F-BDC@UiO-67 prepared in Example 4 (c).

[0070] Figure 3 This is the SEM image of UiO-67 prepared in Comparative Example 1.

[0071] Figure 4 NH prepared in Example 5 2 -BDC@UiO-67 (ab) and SEM images of 2OH-BDC@UiO-67 (cd) prepared in Example 6.

[0072] Figure 5 FT-IR spectra of UiO-67, 16.7% 4F-BDC@UiO-67, 33.3% 4F-BDC@UiO-67, 4F-BDC@UiO-67, 66.7% 4F-BDC@UiO-67 (a); Thermogravimetric analysis of UiO-67 and 4F-BDC@UiO-67 (b), N 2 Adsorption isotherm curve (c), pore size distribution curve (d). Figure 5 As can be seen in (d), the original UiO-67 has a uniform microporous structure (1.72 nm), and the 4F-BDC@UiO-67 prepared in Example 1 exhibits a multi-level pore structure with pore sizes distributed in the range of micropores (1.89 nm) and mesopores (3.33, 4.93, and 6.78 nm).

[0073] Adsorption removal performance verification:

[0074] In order to verify the adsorption and removal ability of the multi-metal organic framework material (4F-BDC@UiO-67) containing hierarchical pores obtained in the present invention on bisphenol pollutants, the bisphenol removal performance of the 4F-BDC@UiO-67 material prepared in Example 1 was measured:

[0075] 20 mg of 4F-BDC@UiO-67 adsorbent was added to bisphenol solutions (20 mL) with different initial concentrations, and the mixture was subjected to ultrasonic adsorption (0.5 h). The removal capacity of the prepared 4F-BDC@UiO-67 material for BPs was obtained by fitting the data obtained from the thermodynamic adsorption experiment using the Langmuir and Freundlich isotherm adsorption models.

[0076] Figure 6Thermodynamic adsorption performance of bisphenol by the 4F-BDC@UiO-67 adsorbent prepared in Example 1, (a) is the adsorption isotherm, (b) is the Langmuir model, and (c) is the Freundlich model.

[0077] Depend on Figure 6 It can be seen that the adsorption process of bisphenol compounds by 4F-BDC@UiO-67 prepared in the present invention conforms to the Langmuir model (R 2 =0.9467–0.9931), indicating that the adsorption process is monolayer molecular adsorption. According to the Langmuir model ( Figure 6 b), the adsorption capacities of 4F-BDC@UiO-67 for bisphenol F (BPF), bisphenol A (BPA), bisphenol B (BPB), and bisphenol AF (BPAF) are 229.89, 364.96, 409.84, and 591.72 mg g, respectively. -1 , indicating that 4F-BDC@UiO-67 has a high removal capacity for bisphenol, which may be because the introduction of CF functional groups, the addition of unsaturated metal sites and the hierarchical pore structure provide more binding sites for the prepared material, increase the interaction between the material and the analyte, and enhance the extraction of BPs, which helps to effectively remove pollutants and improve the sensitivity of the detection method. It can be seen that the prepared multi-metal organic framework material (4F-BDC@UiO-67) adsorbent containing hierarchical pores shows a high practical application potential.

[0078] Effect verification 1:

[0079] (1) In order to verify the effect of the active sites (CF functional group, newly added unsaturated metal sites and multi-level pores) introduced by the preparation method on improving the adsorption performance of the material and to verify the adsorption capacity of the product obtained by the present invention for bisphenol, the 4F-BDC@UiO-67 adsorbent prepared in Example 1 and the NH4O4 adsorbent prepared in Example 5 were subjected to the following tests: 2 The enrichment performance of bisphenols by 2-BDC@UiO-67, 2OH-BDC@UiO-67 prepared in Example 6 and UiO-67 prepared in Comparative Example 1 was compared. Specifically, 15 mg of the above adsorbent was added to a 200 ng / mL mixed standard solution of bisphenol A (BPA), bisphenol B (BPB), bisphenol F (BPF) and bisphenol AF (BPAF) (i.e., the concentration of each bisphenol was 200 ng / mL), and adsorption enrichment was carried out at room temperature, and the adsorption amount was compared after adsorption to saturation.

[0080] Figure 7 This is a comparison chart of the enrichment performance of bisphenol environmental pollutants by the 4F-BDC@UiO-67 adsorbent prepared in Example 1 and the UiO-67 prepared in Comparative Example 1. Figure 8 NH prepared in Example 52 Comparison of the enrichment performance of bisphenol environmental pollutants by 2OH-BDC@UiO-67 prepared in Example 6 and UiO-67 prepared in Comparative Example 1.

[0081] from Figure 7 It can be seen that the adsorption amount of bisphenol A (BPA), bisphenol B (BPB), bisphenol F (BPF), and bisphenol AF (BPAF) by the multi-metal organic framework material containing hierarchical pores (4F-BDC@UiO-67) is 6.3, 3.5, 1.9, and 1.5 times that of the unfunctionalized single-component single-pore UiO-67 (calculated by peak area value). The results show that compared with the unfunctionalized single-component single-pore UiO-67, the multi-metal organic framework material containing hierarchical pores (4F-BDC@UiO-67) prepared by this strategy exhibits better enrichment and removal capacity for bisphenol environmental pollutants, indicating that the adsorbent prepared by this preparation method has great potential in increasing the adsorption performance of the material.

[0082] from Figure 8 It can be seen that the prepared NH 2 The enrichment performance of bisphenol by 2-BDC@UiO-67 and 2OH-BDC@UiO-67 adsorbents was better than that of unfunctionalized single-component single-pore size UiO-67. This result once again proves the potential of the materials prepared by this synthesis strategy in improving the enrichment performance of materials.

[0083] Effect verification 2:

[0084] In order to verify the durability and potential commercial value of the prepared material, 4F-BDC@UiO-67 was used as an example to explore its reusability in enriching bisphenol pollutants. After each enrichment operation (the enrichment operation is the same as the effect verification example 1), the material was washed 4 times with acetonitrile and dried before the next enrichment experiment.

[0085] Fig. 9 This is a graph showing the recycling performance of 4F-BDC@UiO-67 prepared in Example 1. Fig. 9 It can be seen that the prepared material still has good reusability after 8 adsorption-desorption cycles. The enrichment performance of the adsorbent under different cycles is shown in Table 1.

[0086] Table 1

[0087] Cycle times BPF BPA BPB BPAF First cycle 100％ 100％ 100％ 100％ 3rd cycle 98.6％ 95.3％ 92.9％ 98.5％ 5th cycle 95.3％ 99.1％ 91.6％ 96.1％ 8th cycle 91.3％ 92.8％ 88.2％ 90.8％

[0088] Wherein, cycle enrichment performance (%) = bisphenol enrichment of the adsorbent in the Nth cycle / initial bisphenol enrichment of the adsorbent.

[0089] The novel multi-element metal organic framework material 4F-BDC@UiO-67 containing hierarchical pores prepared in Example 1 of the present invention is self-assembled by using dual organic ligands (biphenyl dicarboxylic acid and functionalized terephthalic acid) and metal zirconium ions. With the synergistic effect between the components, it has more diverse active sites and adsorption sites than single-component MOFs (UiO-67 or 4F-UiO-66), and therefore has better adsorption selectivity. In addition, since two organic ligands with different chain lengths are selected, the hierarchical pore structure in the synthetic material can adapt to adsorbates of different sizes, avoiding the limitations of single pore size materials. Compared with the unfunctionalized metal-organic framework material (MOF) containing a single component and a single pore size, the morphology of the multi-metal organic framework material 4F-BDC@UiO-67 containing hierarchical pores of the present invention has changed significantly and contains more affinity sites. Compared with the UiO-67 material, the 4F-BDC@UiO-67 containing newly added CF functional groups, unsaturated metal sites and a multi-level pore structure has greatly increased the enrichment ability of bisphenol, and the enrichment performance is 1.5-6.3 times that of the unfunctionalized UiO-67.

[0090] The solid phase extraction technology constructed by the 4F-BDC@UiO-67 material provided by the present invention exhibits excellent removal performance when adsorbing bisphenol pollutants, and exhibits much higher enrichment performance than the unfunctionalized single-component single-pore UiO-67 in enriching trace BPs in the environment in conjunction with HPLC-DAD, indicating that the prepared new multi-element metal-organic framework material (4F-BDC@UiO-67) containing hierarchical pores has potential application value in removing or detecting or monitoring organic pollutants in the environment using HPLC-DAD.

[0091] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A multi-element metal organic framework material containing hierarchical pores, characterized in that: The product was prepared by solvothermal reaction with biphenyl dicarboxylic acid and functionalized terephthalic acid as organic linkers and zirconium salt as metal source. The functionalized terephthalic acid is tetrafluoroterephthalic acid, 2-aminoterephthalic acid, 2,5-diaminoterephthalic acid, 2-hydroxyterephthalic acid or 2,5-dihydroxyterephthalic acid.

2. The multi-element metal organic framework material containing hierarchical pores according to claim 1, characterized in that: The zirconium salt is zirconium tetrachloride.

3. The method for preparing a multi-element metal organic framework material containing hierarchical pores according to any one of claims 1 to 2, characterized in that: The following steps are involved: The multi-element metal organic framework material containing hierarchical pores is obtained by using biphenyl dicarboxylic acid and functionalized terephthalic acid as organic linkers and zirconium salt as a metal source through solvent thermal reaction.

4. The preparation method according to claim 3, characterized in that: The solvent used in the solvothermal reaction is dimethylformamide.

5. The preparation method according to claim 4, characterized in that: A solution buffer is also added into the solvent thermal reaction system; the solution buffer is benzoic acid.

6. The preparation method according to claim 3, characterized in that: In the solvent thermal reaction system, the concentration of the biphenyl dicarboxylic acid is 4.5-11.5 mM, the concentration of the functionalized terephthalic acid is 2.2-9.2 mM, and the concentration of the zirconium salt is 10-18 mM.

7. The preparation method according to claim 5, characterized in that: In the solvothermal reaction system, the concentration of benzoic acid is 0.2-0.8M.

8. The preparation method according to claim 3, characterized in that: The temperature of the solvent thermal reaction is 100° C.; the time of the solvent thermal reaction is 20-26 hours.

9. Use of the multi-metal organic framework material containing hierarchical pores as described in any one of claims 1 to 2 in removing and enriching environmental organic pollutants.

10. Use of the multi-element metal organic framework material containing hierarchical pores as claimed in any one of claims 1 to 2 in removing and detecting bisphenol pollutants.

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