A 0D / 2D composite metal organic framework material and its preparation method and application

Abstract

The present invention discloses a 0D / 2D composite metal organic framework material and its preparation and application, belonging to the technical field of metal organic framework material preparation. The present invention is based on an in-situ growth strategy and uses a solvothermal method to synthesize a 0D / 2D composite metal organic framework material UiO‑66 / PCN‑134. The synthesis method of the composite metal organic framework material is simple and convenient, and it can efficiently adsorb tetracycline in an aqueous environment and realize in-situ photodegradation, and has great application potential.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal organic framework material preparation, and specifically relates to a 0D / 2D composite metal organic framework material and a preparation method and application thereof. Background Art

[0002] Tetracycline (TC) is widely used due to its low production cost and high antibacterial activity. As one of the commonly used antibiotics, TC often flows into rivers, groundwater and other water bodies with the discharge of domestic wastewater and medical wastewater, and has been frequently detected in various natural water bodies. Due to its high hydrophilicity and low volatility, TC can stably exist and migrate in the water environment, which has an adverse effect on aquatic organisms. TC will also increase the drug resistance of bacteria, and after entering the human body with drinking water, it affects the balance of human flora and poses a threat to human public health. Therefore, effective methods are urgently needed to remove it.

[0003] So far, researchers have used a variety of technologies to remove tetracycline, such as biodegradation, membrane separation, adsorption and advanced oxidation processes. In practical applications, tetracycline mainly comes from domestic sewage, which has a large amount of water and a very low concentration. The use of an adsorption-degradation integrated treatment method can reduce energy consumption, destructively remove pollutants and achieve in-situ regeneration of adsorbents. However, this technology has very high requirements for materials, and the required materials should have both good adsorption and degradation capabilities.

[0004] In recent years, as a new type of porous material, metal organic frameworks (MOFs) have attracted much attention. It is formed by the self-assembly of inorganic metal centers (metal ions or metal clusters) and bridging organic ligands, and has the advantages of high specific surface area, large porosity, and modifiability. At present, in order to further expand the application of MOFs in different fields, multifunctional composite materials have been constructed. Many studies are devoted to growing one MOF on another MOF to form a MOF / MOF heterostructure. Due to the synergistic effect between different MOFs, MOF / MOF composites have shown great potential in many applications, including gas adsorption, gas separation, catalysis and sensing. Generally speaking, the two composite MOFs need to match the lattice parameters and have a small lattice mismatch. The synthesized composite material has the pore structure and active sites of both, and can be used as a multifunctional material.

[0005] Based on this, the present invention proposes a modification strategy of growing a 0D metal organic framework onto a 2D metal organic framework. In the synthesized 0D / 2D composite metal organic framework material, due to lattice adaptation, nanoparticles UiO-66 grow on the surface of 2D PCN-134 nanoplates, thereby forming a 0D / 2D UiO-66 / PCN-134 heterostructure. The material has both high adsorption capacity and photoreactivity, and can be used for adsorption-degradation removal of tetracycline in water environments. Summary of the invention

[0006] The purpose of the present invention is to provide a 0D / 2D composite metal organic framework material and its preparation method and application. The composite metal organic framework material has both high adsorption capacity and photoreactivity, can efficiently adsorb and remove tetracycline in an aqueous environment, and its preparation process is simple and has good application prospects.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A 0D / 2D composite metal organic framework material is prepared by in-situ growing a zero-dimensional (0D) nano-granular metal organic framework UiO-66 on the surface of a two-dimensional (2D) nano-plate-shaped metal organic framework PCN-134; the material specifically comprises the following steps:

[0009] (1) Preparation of nanoplate-like metal-organic framework: 30 mg of zirconium oxychloride octahydrate and 2.2 mL of acetic acid were added to 2 mL of DMF, heated at 100 °C for 1 hour, and then cooled to room temperature; 7 mg of tetrakis(4-carboxyphenyl)porphyrin and 10 mg of 1,3,5-tris(4-carboxyphenyl)benzene were added to 7 mL of DMF, and ultrasonicated for 10 minutes; the two prepared solutions were then mixed, ultrasonicated for 10-20 minutes, and heated at 120 °C for 24 hours. The solid was collected by centrifugation, washed twice with acetone, and then vacuum dried at 120 °C for 12 hours to obtain a 2D nanoplate-like metal-organic framework PCN-134; after cooling to room temperature, it was washed twice with DMF and dissolved in 10 mL of DMF to obtain a PCN-134 solution;

[0010] (2) Preparation of 0D / 2D composite metal-organic framework material: 33.4 mg of zirconium tetrachloride, 25 mg of terephthalic acid and 0.7 mL of acetic acid were dissolved in 10 mL of DMF, and then added to the PCN-134 solution prepared in step 2). After sufficient oscillation, ultrasonication was performed for 10-20 minutes, and then heating was performed at 120 °C for 24 hours. The solid was collected by centrifugation and washed twice with DMF by centrifugation. Then, vacuum drying was performed at 120 °C for 12 hours to obtain the 0D / 2D composite metal-organic framework material UiO-66 / PCN134.

[0011] The obtained 0D / 2D composite metal-organic framework material can efficiently adsorb and degrade tetracycline in water environment under the presence of visible light.

[0012] The significant advantages of the present invention are:

[0013] (1) The present invention grows a 0D metal organic framework UiO-66 on the surface of a 2D nanoplate-like metal organic framework PCN-134, and successfully synthesizes a 0D / 2D composite metal organic framework material UiO-66 / PCN-134 for the first time.

[0014] (2) The preparation method of the present invention is simple and convenient and can quickly synthesize the composite material.

[0015] (3) The composite material prepared by the present invention has the advantages of two metal organic framework materials, and thus has good adsorption performance and photoreactivity, and can quickly and efficiently remove tetracycline in the water environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the X-ray powder diffraction pattern of the 0D / 2D composite metal organic framework material obtained in Example 1;

[0017] Figure 2 TEM comparison images of the 2D metal organic framework (a) and the 0D / 2D composite metal organic framework material (b) obtained in Example 1;

[0018] Figure 3 A comparison diagram of the adsorption-photodegradation process of tetracycline using the 0D / 2D composite metal organic framework material obtained in Example 1;

[0019] Figure 4 This is a comparison chart of the removal efficiency of tetracycline by the 0D / 2D composite metal-organic framework material obtained in Example 1 and common commercial materials. DETAILED DESCRIPTION

[0020] In order to make the contents of the present invention easier to understand, the technical solution of the present invention is further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0021] Example 1

[0022] The preparation of a 0D / 2D composite metal organic framework material comprises the following steps:

[0023] (1) Preparation of 2D metal organic framework: 30 mg of zirconium oxychloride octahydrate and 2.2 mL of acetic acid were added to 2 mL of DMF, heated at 100 °C for 1 hour, and then cooled to room temperature; in another vial, 7 mg of tetrakis(4-carboxyphenyl)porphyrin and 10 mg of 1,3,5-tris(4-carboxyphenyl)benzene were added to 7 mL of DMF, and ultrasonicated for 10 minutes; then the two prepared solutions were mixed, ultrasonicated for 10-20 minutes, and heated at 120 °C for 24 hours, and the solid was collected by centrifugation, washed twice with acetone, and then vacuum dried at 120 °C for 12 hours to obtain a 2D nanoplate metal organic framework PCN-134; after cooling to room temperature, it was washed twice with DMF and dissolved in 10 mL of DMF to obtain a PCN-134 solution;

[0024] (2) Preparation of 0D / 2D composite metal-organic framework material: 33.4 mg of zirconium tetrachloride, 25 mg of terephthalic acid and 0.7 mL of acetic acid were dissolved in 10 mL of DMF, and then added to the PCN-134 solution prepared in step 2). After thorough oscillation, ultrasonication was performed for 10 minutes, and then heating was performed at 120 °C for 24 hours. The solid was collected by centrifugation and washed twice with DMF by centrifugation. Then, the solid was vacuum dried at 120 °C for 12 hours to obtain the 0D / 2D composite metal-organic framework material UiO-66 / PCN134.

[0025] Product Characterization

[0026] Figure 1 This is the X-ray powder diffraction pattern of the 0D / 2D composite metal-organic framework material obtained in Example 1. As can be seen from the figure, the main diffraction peaks of the 0D / 2D composite metal-organic framework material have characteristic peaks of both the 0D metal-organic framework and the 2D metal-organic framework, indicating that the metal-organic framework is successfully composited and the composite does not change the crystal structure of the metal-organic framework.

[0027] Figure 2 The transmission electron microscopy comparison of the 2D metal organic framework (a) and the 0D / 2D composite metal organic framework material (b) obtained in Example 1. It can be seen from the figure that the 2D metal organic framework is a hexagonal nanoplate with a smooth surface under the microscope (a); while the 0D / 2D composite metal organic framework material is formed by coating the surface of the 2D metal organic framework PCN-134 with the nano-granular 0D metal organic framework UiO-66 (b).

[0028] Performance Testing

[0029] Tetracycline was adsorbed and photodegraded using the 0D / 2D composite metal-organic framework material obtained in Example 1. The experimental conditions were as follows: 10 mg of the 0D / 2D composite metal-organic framework material was added to 100 mL of a 20 mg / L tetracycline aqueous solution, and the reaction was oscillated in a constant temperature shaker (200 rpm, 25°C) under dark conditions for 150 minutes to reach adsorption and desorption equilibrium, and then the light was turned on for a photocatalytic degradation experiment. During the experiment, solution samples were collected, and the tetracycline concentration was measured at 357 nm by a UV-vis spectrophotometer.

[0030] Figure 3 The process comparison diagram of the adsorption-photodegradation removal of tetracycline by the 2D metal organic framework (PCN-134) and the 0D / 2D composite metal organic framework material obtained in Example 1. As can be seen from the figure, the 0D / 2D composite metal organic framework and the 2D metal organic framework material both reached the adsorption-desorption equilibrium state after 150 min of dark adsorption, at which time the tetracycline concentration in the solution no longer decreased, but the adsorption rate of tetracycline by the 0D / 2D composite metal organic framework (50%) was significantly higher than that of the 2D metal organic framework material (40%); and under visible light irradiation, since the 0D / 2D composite metal organic framework and the 2D metal organic framework material can photocatalytically degrade tetracycline, the concentration of tetracycline in the solution further decreased. After irradiation for 120 min, the 0D / 2D composite metal organic framework and the 2D metal organic framework material degraded 46% and 37% of tetracycline, respectively, so the total removal rates of tetracycline by the two were 96% and 77%, respectively. According to previous literature reports (Dong Wenbo. Preparation of UiO-66 and its composite materials and experimental study on tetracycline adsorption and photocatalytic degradation. Hunan University, 2019. 003892.), the removal rate of tetracycline by UiO-66 is only 55.5%. This shows that the adsorption and photodegradation performance of the obtained 0D / 2D composite metal organic framework material for tetracycline is significantly better than that of single UiO-66 and PCN-134, which proves that the composite of 2D metal organic framework PCN-134 and UiO-66 has a synergistic effect.

[0031] Figure 4 This is a comparison of the removal efficiency of tetracycline by 0D / 2D composite metal organic framework materials and common commercial materials. From previous literature, we know that zirconium dioxide (Yu JP, Guo YF, Zhao YR, et al. Visible-lightphotocatalytic tetracycline degradation over nanodots-assembledN-ZrO 2- xnanostructures: Performance, degradation pathways and mechanistic insight. Journal of Alloys and Compounds, 2022, 895:162582), graphite phase carbon nitride (Huang LJ, Liu H, Wang Y, et al. Construction of ternary Bi 2 O 3 / biochar / gC 3 N 4 heterojunction to accelerate photoinduced carrier separation for enhancedtetracycline photodegradation. Applied Surface Science, 2023, 616:156509) and titanium dioxide (P25) (Vo T K. Mo-modifiedTiO2 mesoporous microspheres prepared by spraypyrolysis for adsorption-photocatalytic water remediation. Journal of Sol-GelScience and Technology, 2022,103(3): 853-864.) had removal rates of tetracycline of <10%, 32.8% and 40%, respectively, while the 0D / 2D composite metal-organic framework material of the present invention can remove 96% of tetracycline, proving that it has great potential for the removal of tetracycline.

[0032] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. Application of an 0D / 2D composite metal organic framework material in the adsorption and degradation of tetracycline in an aqueous environment, characterized in that: The 0D / 2D composite metal organic framework material is synthesized by in-situ growing a zero-dimensional nano-granular metal organic framework UiO-66 on the surface of a two-dimensional nano-plate-shaped metal organic framework PCN-134.

2. The use according to claim 1, characterized in that: The preparation method of the 0D / 2D composite metal organic framework material specifically comprises the following steps: (1) Preparation of nanoplate-like metal-organic framework: 30 mg of zirconium oxychloride octahydrate and 2.2 mL of acetic acid were added to 2 mL of DMF, heated at 100 °C for 1 hour, and then cooled to room temperature; 7 mg of tetrakis(4-carboxyphenyl)porphyrin and 10 mg of 1,3,5-tris(4-carboxyphenyl)benzene were added to 7 mL of DMF, and ultrasonicated for 10 minutes; the two prepared solutions were then mixed, ultrasonicated for 10-20 minutes, and heated at 120 °C for 24 hours, and the solid was collected by centrifugation, washed with acetone, and vacuum dried to obtain a nanoplate-like metal-organic framework PCN-134; the solid was washed twice with DMF and dissolved in 10 mL of DMF to obtain a PCN-134 solution; (2) Preparation of 0D / 2D composite metal-organic framework material: 33.4 mg of zirconium tetrachloride, 25 mg of terephthalic acid and 0.7 mL of acetic acid were dissolved in 10 mL of DMF, and then added to the PCN-134 solution obtained in step (1). After sufficient oscillation, the mixture was ultrasonicated for 10-20 minutes and then heated at 120°C for 24 hours. The solid was collected by centrifugation, washed with DMF by centrifugation and dried in vacuo to obtain the 0D / 2D composite metal-organic framework material.

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