A hyperbranched magnetic modified MOFs-based composite material, a preparation method and application thereof

Abstract

The application discloses a hyperbranched magnetic modified MOFs-based composite material and a preparation method and application thereof, and the preparation steps of the hyperbranched magnetic modified MOFs-based composite material include the following steps: preparing a magnetic Fe3O4 magnetic material or purchasing a commercially available one; preparing a Zn-MOF material by using sodium hydroxide, trimesic acid, N-N dimethylformamide, ethanol and zinc acetate dihydrate; preparing a carboxyl-terminated hyperbranched polymer by using diethanolamine, methanol, methyl acrylate, trimethylolpropane, p-toluene sulfonic acid and maleic anhydride; and reacting the magnetic Fe3O4 with the Zn-MOF and the carboxyl-terminated hyperbranched polymer to obtain the hyperbranched magnetic modified MOFs-based composite material. The hyperbranched magnetic modified MOFs-based composite material prepared by using the application can remove the chroma in water, can realize the effect of low dosage and high removal rate, and has stable recycling regeneration effect and high removal efficiency.

Description

Technical Field

[0001] This invention relates to the field of chemical engineering technology, specifically to a hyperbranched magnetically modified MOFs-based composite material, its preparation method, and its application. Background Technology

[0002] In the current wastewater treatment field, high-chroma wastewater contains complex pollutants and is characterized by high COD and recalcitrant degradation. Adsorption, as one of the main methods for removing pollutants from water bodies, involves adding adsorbents that quickly contact the wastewater pollutants and selectively adsorb the target substances through chemical bonds and other forces, thus removing the pollutants by adhering to the adsorbent surface. However, commonly used adsorbents have drawbacks such as weak adsorption capacity for some pollutants, poor regeneration capacity, and the generation of toxic byproducts during the treatment process.

[0003] MOFs, or metal-organic frameworks, are a class of coordination polymers formed by the self-assembly of transition metal ions and organic polydentate ligands containing nitrogen, oxygen, sulfur, and other atoms. They possess a three-dimensional porous structure, with their microstructure mainly consisting of nodes and connecting bridges. Typically, metal ions act as nodes, and organic ligands serve as connecting bridges, forming a three-dimensional, extended network structure. MOFs exhibit strong stability, high specific surface area, high porosity, ease of functionalization, and tunable pore size, and are frequently used for the removal of pollutants from water. However, traditional MOFs materials often suffer from difficulties in separation and recovery, and their adsorption capacity still needs improvement.

[0004] To improve the recyclability of MOFs (Metal-Oxide-Facility) materials, magnetic Fe3O4 is typically used to assemble MOFs, forming core-shell magnetic MOFs with Fe3O4 as the magnetic core. Furthermore, to further enhance the adsorption properties of magnetic MOFs, they are often grafted with polymers before practical application to improve their adsorption performance. Commonly used polymers for grafting magnetic MOFs include chitosan, PEI, and PDDA. After modification, these polymers can graft functional groups such as –COOH, –NH2, and –OH onto the resulting magnetic MOF composite material. These functional groups can adsorb and remove pollutants through hydrogen bonding, π bonding, and electrostatic adsorption. However, in practical applications, the polymers used for grafting modification of magnetic MOFs composites are generally chain or linear polymers. These polymers are mainly grafted onto the surface of MOFs materials through electrostatic forces and van der Waals forces to form active adsorption sites for MOFs materials. However, as the magnetic MOFs materials are repeatedly regenerated, these adsorption sites are gradually replaced or complexed on their surface, resulting in the adsorption stability and regeneration stability of magnetic MOFs composites still needing to be improved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a hyperbranched magnetically modified MOFs-based composite material, its preparation method, and its application. The hyperbranched magnetically modified MOFs-based composite material prepared using the method of this invention not only significantly improves the recycling efficiency of traditional Zn-MOF materials but also further reduces the amount of material used, improves the treatment effect, and maintains stable performance.

[0006] To achieve the above objectives, the specific solution adopted by the present invention is as follows:

[0007] A method for preparing hyperbranched magnetically modified MOFs-based composite materials includes the following steps:

[0008] S1. Preparation of Zn-MOF

[0009] S11. Sodium hydroxide, pyromellitic acid, N,N dimethylformamide, ethanol and deionized water are mixed evenly in a mass ratio of 1:1.75:30:200:420 and then ultrasonically assembled in a constant temperature water bath at 30°C to obtain mixed solution A.

[0010] S12. Add zinc acetate dihydrate and sodium hydroxide to mixed solution A at a mass ratio of (1-6):1 and react fully. Separate by centrifugation, wash with water and alcohol three times each, and dry under vacuum to obtain Zn-MOF.

[0011] S2. Preparation of magnetic Zn-MOF

[0012] The magnetic Fe3O4 and the Zn-MOF prepared in step S1 were dispersed in an appropriate amount of ethanol solution at a mass ratio of 1:(1~10). The mixture was first stirred evenly in a water bath at 30°C, then ultrasonically assembled, and finally dried to obtain the magnetic Zn-MOF material.

[0013] S3. Preparation of carboxyl-terminated hyperbranched polymers

[0014] S31. Mix diethanolamine and methanol in a volume ratio of 1:3 to 3:1, and stir at room temperature until the diethanolamine is completely dissolved to obtain mixed solution B.

[0015] S32. Take an appropriate amount of methyl acrylate and slowly add it dropwise to mixed solution B, and mix thoroughly. Then react at 35°C for 4 hours and at 85°C for 1.5 hours in sequence. The degree of polymerization of the monomer is increased by segmented temperature program to obtain mixed solution C. S33. Add trimethylolpropane and p-toluenesulfonic acid to mixed solution C at a molar ratio of (50-80):1. First heat at 120°C for 3 hours, and then heat at 100°C for 1 hour. The monomer of the polymer is stabilized and the esterification reaction is promoted by segmented temperature program to obtain mixed solution D.

[0016] S34. Maleic anhydride and p-toluenesulfonic acid were added to mixed solution D in a molar ratio of 20:1 to 60:1, and reacted at 80°C for 2.5 h and 130°C for 12 h, respectively. The monomer reaction was made more complete and the polymerization was more complete by using programmed temperature rise and heat preservation reaction to obtain a carboxyl-terminated hyperbranched polymer.

[0017] S4, Synthetic hyperbranched magnetically modified MOFs-based composite materials

[0018] The magnetic Zn-MOF prepared in step S2 and the carboxyl-terminated hyperbranched polymer prepared in step S3 are dissolved in a mixed solution of acetic acid and nitric acid at a mass ratio of 1:2 to 4:1. The resulting solution is ultrasonically assembled, repeatedly washed with deionized water, and then thoroughly dried to obtain the hyperbranched magnetically modified MOFs-based composite material.

[0019] As a preferred embodiment, in step S32, the volume ratio of methyl acrylate to mixed solution B is 1:2 to 4:1.

[0020] A hyperbranched magnetically modified MOFs-based composite material is prepared by the method described above.

[0021] A hyperbranched magnetically modified MOFs-based composite material, the monomer structure of which is as follows:

[0022]

[0023] Application of a hyperbranched magnetically modified MOFs-based composite material in the field of color removal from water.

[0024] As a preferred embodiment, hyperbranched magnetically modified MOFs-based composite materials are added to high-chroma wastewater at a final concentration of 20 mg / L to 2500 mg / L. The mixture is continuously stirred at a temperature of 20°C to 60°C and a speed of 80 rpm to 150 rpm to remove color from the water. The hyperbranched magnetically modified MOFs-based composite materials are then regenerated under the action of a permanent magnet. The regenerated hyperbranched magnetically modified MOFs-based composite materials can be used again to remove color from water.

[0025] As a preferred embodiment, the high-chroma wastewater includes, but is not limited to, wastewater containing dyes, metallurgical wastewater, drilling wastewater, mining wastewater, and water bodies with algal blooms.

[0026] The hyperbranched magnetically modified MOFs-based composite material of this invention has a simple preparation method. First, magnetic Fe3O4, Zn-MOF, and HBP-COOH are synthesized separately. Then, they are assembled by ultrasound, with Zn-MOF and HBP-COOH encapsulating the Fe3O4 surface to form a core-shell structure, thus preparing the hyperbranched magnetically modified MOFs-based composite material. Compared with Zn-MOF, this hyperbranched magnetically modified MOFs-based composite material has a larger specific surface area after modification, providing a larger surface area for solution decolorization. When used to treat colorimetric wastewater, it removes macromolecules through electrostatic adsorption, π-π interactions, and the formation of stable metal ligands with the colorimetric macromolecules in the water through open metal sites. Furthermore, the intermolecular hydrogen bonds formed by amino, hydroxyl, and carboxyl groups on the material can interact with intramolecular hydrogen bonds for removal. Simultaneously, the presence of magnetic Fe3O4 makes it easy to separate from water by applying a magnetic field.

[0027] Beneficial effects:

[0028] 1) Traditional MOF materials typically have internal pore sizes of around 2 nm, which to some extent restricts the diffusion of target pollutants within the pores, thus limiting adsorption efficiency and making recovery difficult. The hyperbranched magnetically modified MOF-based composite material of this invention, by encapsulating Zn-MOF on the surface of Fe3O4 to form a core-shell structure with Fe3O4 as the core, and further assembling it with a terminal carboxyl-terminated hyperbranched polymer, significantly enhances adsorption capacity. This allows for efficient and stable adsorption of color molecules in water. Compared to traditional adsorbents, this hyperbranched magnetically modified MOF-based composite material requires less dosage, exhibits strong adsorption capacity, and can achieve efficient and stable regeneration, enhancing the removal of color molecules from water. Regarding material regeneration, the hyperbranched magnetically modified MOF-based composite material can be recovered through efficient magnetic separation and then regenerated using ultrasonic methods, enabling multiple cycles of regeneration. This provides a theoretical basis and technical support for the development and preparation of novel environmentally friendly adsorbent materials.

[0029] 2) The hyperbranched magnetically modified MOFs-based composite material of the present invention is used to treat high-color wastewater, and no pretreatment such as pH adjustment, dilution, or centrifugation is required before treatment.

[0030] 3) The hyperbranched magnetically modified MOFs-based composite material used in this invention has a simple preparation process, is highly operable, can achieve rapid separation by applying an external magnetic field, and requires a low dosage.

[0031] 4) The hyperbranched magnetically modified MOFs-based composite material used in this invention exhibits strong regeneration stability, a simple and easy-to-operate regeneration method, and stable regeneration results. After adsorption, the hyperbranched magnetically modified MOFs-based composite material is separated by applying an external magnetic field. Then, it is used for color molecule separation via ultrasonication. After washing several times with deionized water, it can be reused in the adsorption treatment of color wastewater. Compared with traditional MOFs materials, this material can achieve stable recycling and regeneration, significantly reducing usage costs.

[0032] 5) The hyperbranched magnetically modified MOFs-based composite material and its application provided by this invention have good adsorption effect, with a removal rate of over 80% in 0.5 hours and over 90% in 2 hours. It has low requirements for separation equipment and can be promoted on a large scale for industrial application.

[0033] 6) The hyperbranched magnetically modified MOFs-based composite material provided by the present invention can be separated from water by an external magnetic field, which can prevent the material from entering the water and accumulating in the food chain, as well as the generation of toxic byproducts, thus avoiding potential health risks. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0035] This invention discloses a method for preparing hyperbranched magnetically modified MOFs-based composite materials, comprising the following steps:

[0036] S1. Prepare magnetic Fe3O4 by coprecipitation method or commercially available method.

[0037] The steps for preparing magnetic Fe3O4 by coprecipitation are as follows:

[0038] S11. Dissolve FeSO4 7H2O and FeCl3 6H2O in deionized water at a molar ratio of 1:2. Add an appropriate amount of NH4OH at room temperature and stir vigorously to bring the pH of the solution to 10.

[0039] S12. Take the lower black precipitate from the solution, heat it at 80℃ for 30 min, wash it repeatedly 3-5 times, and freeze-dry it to obtain magnetic Fe3O4; S2. Prepare Zn-MOF

[0040] S21. Sodium hydroxide, pyromellitic acid, N,N dimethylformamide, ethanol and deionized water are mixed evenly in a mass ratio of 1:1.75:30:200:420 and sonicated in a constant temperature water bath at 30℃ for 30 min to obtain mixed solution A.

[0041] S22. Add zinc acetate dihydrate and sodium hydroxide to mixed solution A at a mass ratio of (1-6):1 and react for 1.5 h. Centrifuge (8000 r / min), wash with water and alcohol three times each, and dry under vacuum at 40 °C for 2 h to obtain Zn-MOF.

[0042] S3. Preparation of magnetic Zn-MOF

[0043] The magnetic Fe3O4 prepared in step S1 and the Zn-MOF prepared in step S2 are dispersed in an appropriate amount of ethanol solution at a mass ratio of 1:(1~10). The mixture is first stirred in a water bath at 30℃ for 3 hours, then sonicated for 1 hour, and dried at 60℃ to obtain the magnetic Zn-MOF material.

[0044] S4. Preparation of carboxyl-terminated hyperbranched polymer (HBP-COOH)

[0045] S41. Mix diethanolamine and methanol in a volume ratio of 1:3 to 3:1, and stir at room temperature until the diethanolamine is completely dissolved to obtain mixed solution B.

[0046] S42. Take an appropriate amount of methyl acrylate, slowly add the methyl acrylate dropwise to the mixed solution B and mix thoroughly. The volume ratio of methyl acrylate to mixed solution B is 1:2 to 4:1. Then react at 35°C for 4 hours and at 85°C for 1.5 hours to obtain mixed solution C.

[0047] S43. Trimethylolpropane and p-toluenesulfonic acid were added to mixed solution C in a molar ratio of (50-80):1. The mixture was first heated at 120°C for 3 hours, and then heated at 100°C for 1 hour to obtain mixed solution D.

[0048] S44. Maleic anhydride and p-toluenesulfonic acid were added to mixed solution D in a molar ratio of 20:1 to 60:1, and reacted at 80°C for 2.5 h and 130°C for 12 h, respectively, to obtain a carboxyl-terminated hyperbranched polymer.

[0049] S5, Synthetic hyperbranched magnetically modified MOFs-based composite materials

[0050] The magnetic Zn-MOF prepared in step S3 and the carboxyl-terminated hyperbranched polymer prepared in step S4 were dissolved in a mixed solution of acetic acid (1%) and nitric acid (65%) with a volume ratio of 1:2 to 4:1 at a mass ratio of 1:2. The resulting solution was sonicated for 30 min, washed repeatedly with deionized water 6 times, and then dried at 70 °C for 24 h to obtain the hyperbranched magnetically modified MOFs-based composite material (Fe3O4@Zn-MOF / HBP-COOH).

[0051] A hyperbranched magnetically modified MOFs-based composite material, prepared by the above method, has the following monomer structural formula:

[0052]

[0053] The application of hyperbranched magnetically modified MOFs-based composite materials in the removal of color from water is as follows: hyperbranched magnetically modified MOFs-based composite materials are added to high-color wastewater at a final concentration of 20 mg / L to 2500 mg / L. The mixture is continuously stirred at a temperature of 20℃ to 60℃ and a speed of 80 rpm to 150 rpm to fully adsorb color macromolecules in the water. Then, it is dispersed under ultrasound for 30 min (ultrasound frequency 25 kHz to 40 kHz). Finally, the hyperbranched magnetically modified MOFs-based composite materials are regenerated under the action of a permanent magnet. The regenerated hyperbranched magnetically modified MOFs-based composite materials can be used again to remove color from water.

[0054] The high-chromatic wastewater includes, but is not limited to, wastewater containing dyes, metallurgical wastewater, drilling wastewater, mining wastewater, and water bodies with algal blooms. The dyes contained in the wastewater include, but are not limited to, malachite green, methylene blue, basic fuchsin, rhodamine B, and crystal violet.

[0055] Specifically, the applicable pH range for high-color wastewater can be broadened to 3.0-10.

[0056] Preferably, the hyperbranched magnetically modified MOFs-based composite material is added to the high-chroma wastewater at a dosage of 20-1000 mg / L, with a stirring time of 2 hours and a stirring speed of 100 rpm.

[0057] It should be noted that, since the embodiments of the present invention involve both preparation methods and application embodiments, these two aspects are described separately in this specification.

[0058] First, the technical solution of the present invention will be described in detail below with reference to specific embodiments of the preparation method.

[0059] Example 1-1

[0060] A method for preparing hyperbranched magnetically modified MOFs-based composite materials includes the following steps:

[0061] S1. Preparation of Zn-MOF

[0062] S11. Prepare a mixture of sodium hydroxide, pyromellitic acid (H3BTC), N,N dimethylformamide, ethanol and deionized water in a mass ratio of 1:1.75:30:200:420; sonicate in a constant temperature water bath at 30℃ for 30 min to obtain mixed solution A.

[0063] S12. Add zinc acetate dihydrate and sodium hydroxide to mixed solution A at a mass ratio of 1:1 and react for 1.5 h. Centrifuge (8000 r / min), wash with water and alcohol three times each, and vacuum dry at 40 °C for 2 h to obtain Zn-MOF.

[0064] S2. Preparation of magnetic Zn-MOF

[0065] Magnetic Fe3O4 and Zn-MOF from step ② were dispersed in an appropriate amount of ethanol solution at a mass ratio of 1:1. After stirring in a water bath at 30℃ for 3 hours and sonicating for 1 hour, the mixture was dried at 60℃ to obtain magnetic Zn-MOF.

[0066] S3. Preparation of carboxyl-terminated hyperbranched polymer (HBP-COOH)

[0067] S31. Diethanolamine and methanol are mixed at a volume ratio of 1:3 and stirred at room temperature until the diethanolamine is completely dissolved to obtain mixed solution B.

[0068] S32. Methyl acrylate and mixed solution B are slowly added dropwise to the solution at a volume ratio of 1:2 to ensure thorough mixing. The mixture is then reacted at 35℃ and 85℃ for 4 hours and 1.5 hours respectively to obtain mixed solution C.

[0069] S33. Trimethylolpropane and p-toluenesulfonic acid were added to mixed solution C at a molar ratio of 50:1, and heated at 120℃ and 100℃ for 3 h and 1 h respectively to obtain mixed solution D.

[0070] S34. Maleic anhydride and p-toluenesulfonic acid were added to mixed solution D at a molar ratio of 20:1, and reacted at 80℃ and 130℃ for 2.5h and 12h, respectively, to obtain a carboxyl-terminated hyperbranched polymer (HBP-COOH).

[0071] S4, Synthetic hyperbranched magnetically modified MOFs-based composite materials

[0072] Magnetic Zn-MOF and carboxyl-terminated hyperbranched polymer were dissolved in a 1:1 solution of acetic acid (1%) and nitric acid (65%) at a mass ratio of 1:2. The resulting solution was sonicated for 30 min, washed repeatedly with deionized water 6 times, and dried at 70 °C for 24 h to obtain hyperbranched magnetically modified MOFs-based composite material.

[0073] Examples 1-2

[0074] A method for preparing hyperbranched magnetically modified MOFs-based composite materials includes the following steps:

[0075] S1. Preparation of Zn-MOF

[0076] S11. Prepare a mixed solution by mixing sodium hydroxide, trimesic acid (H3BTC), N,N-dimethylformamide, ethanol, and deionized water in a mass ratio of 1:1.75:30:200:420. Sonicate the solution in a constant temperature water bath at 30°C for 30 minutes to obtain mixed solution A.

[0077] S12. Add zinc acetate dihydrate and sodium hydroxide to mixed solution A at a mass ratio of 6:1 and react for 1.5 h. Centrifuge (8000 r / min), wash with water and alcohol three times each, and vacuum dry at 40 °C for 2 h to obtain Zn-MOF.

[0078] S2. Preparation of magnetic Zn-MOF

[0079] Magnetic Fe3O4 and Zn-MOF from step ② were dispersed in an appropriate amount of ethanol solution at a mass ratio of 1:10. After stirring in a water bath at 30℃ for 3 hours and sonicating for 1 hour, the mixture was dried at 60℃ to obtain magnetic Zn-MOF.

[0080] S3. Preparation of carboxyl-terminated hyperbranched polymer (HBP-COOH)

[0081] S31. Diethanolamine and methanol are mixed at a volume ratio of 3:1 and stirred at room temperature until the diethanolamine is completely dissolved to obtain mixed solution B.

[0082] S32. Methyl acrylate and mixed solution B are slowly added dropwise to the solution at a volume ratio of 4:1 to ensure thorough mixing. The mixture is then reacted at 35℃ and 85℃ for 4 hours and 1.5 hours respectively to obtain mixed solution C.

[0083] S33. Trimethylolpropane and p-toluenesulfonic acid were added to mixed solution C at a molar ratio of 80:1, and heated at 120℃ and 100℃ for 3 h and 1 h respectively to obtain mixed solution D.

[0084] S34. Maleic anhydride and p-toluenesulfonic acid were added to mixed solution D at a molar ratio of 60:1, and reacted at 80℃ and 130℃ for 2.5h and 12h, respectively, to obtain a carboxyl-terminated hyperbranched polymer (HBP-COOH).

[0085] S4, Synthetic hyperbranched magnetically modified MOFs-based composite materials

[0086] Magnetic Zn-MOF and carboxyl-terminated hyperbranched polymer were dissolved in a 1:1 solution of acetic acid (1%) and nitric acid (65%) at a mass ratio of 4:1. The resulting solution was sonicated for 30 min, washed repeatedly with deionized water 6 times, and dried at 70 °C for 24 h to obtain hyperbranched magnetically modified MOFs-based composite material.

[0087] Examples 1-3

[0088] A method for preparing hyperbranched magnetically modified MOFs-based composite materials includes the following steps:

[0089] S1. Preparation of Zn-MOF

[0090] S11. Prepare a mixed solution by mixing sodium hydroxide, trimesic acid (H3BTC), N,N-dimethylformamide, ethanol, and deionized water in a mass ratio of 1:1.75:30:200:420. Sonicate the solution in a constant temperature water bath at 30°C for 30 minutes to obtain mixed solution A.

[0091] S12. Add zinc acetate dihydrate and sodium hydroxide to the mixed solution in step ① at a mass ratio of 3:1 and react for 1.5 h. Centrifuge (8000 r / min), wash with water and alcohol three times each, and vacuum dry at 40 °C for 2 h to obtain Zn-MOF.

[0092] S2. Preparation of magnetic Zn-MOF

[0093] Magnetic Fe3O4 and Zn-MOF from step ② were dispersed in an appropriate amount of ethanol solution at a mass ratio of 1:5. After stirring in a water bath at 30℃ for 3 hours and sonicating for 1 hour, the mixture was dried at 60℃ to obtain magnetic Zn-MOF.

[0094] S3. Preparation of carboxyl-terminated hyperbranched polymer (HBP-COOH)

[0095] S31. Diethanolamine and methanol are mixed at a volume ratio of 0.9:1 and stirred at room temperature until the diethanolamine is completely dissolved to obtain mixed solution B.

[0096] S32. Methyl acrylate and mixed solution B are slowly added dropwise to the solution at a volume ratio of 2:1 to ensure thorough mixing. The mixture is then reacted at 35℃ and 85℃ for 4 hours and 1.5 hours respectively to obtain mixed solution C.

[0097] S33. Trimethylolpropane and p-toluenesulfonic acid were added to mixed solution C at a molar ratio of 60:1, and heated at 120℃ and 100℃ for 3 h and 1 h respectively to obtain mixed solution D.

[0098] S34. Maleic anhydride and p-toluenesulfonic acid were added to mixed solution D at a molar ratio of 35:1, and reacted at 80℃ and 130℃ for 2.5h and 12h, respectively, to obtain a carboxyl-terminated hyperbranched polymer (HBP-COOH).

[0099] S4, Synthetic hyperbranched magnetically modified MOFs-based composite materials

[0100] Magnetic Zn-MOF and carboxyl-terminated hyperbranched polymer were dissolved in a 1:1 solution of acetic acid (1%) and nitric acid (65%) at a mass ratio of 4:5. The resulting solution was sonicated for 30 min, washed repeatedly with deionized water 6 times, and dried at 70 °C for 24 h to obtain hyperbranched magnetically modified MOFs-based composite material.

[0101] Secondly, the technical solution of the present invention will be described in detail below with reference to specific embodiments in terms of application.

[0102] Example 2-1

[0103] The hyperbranched magnetically modified MOFs-based composite material prepared in Example 1-1 was added to a malachite green dye solution (pH = 5.89) at a final concentration of 20 mg / L. After thorough stirring (120 rpm), the solution was allowed to settle under a 1200 G magnetic field. After 2 hours, the absorbance of the supernatant was measured, and the malachite green concentration in the supernatant was calculated using the standard curve equation. Finally, the removal rate was calculated using formula (1), yielding a removal rate of 95.8%. After adsorption, the Fe3O4@Zn-MOF / HBP-COOH was regenerated by ultrasound, and the regeneration rate was calculated according to formula (2), which showed a regeneration rate of 99.5%. The regenerated Fe3O4@Zn-MOF / HBP-COOH was then added to the same malachite green solution at a final concentration of 20 mg / L. After stirring thoroughly (120 rpm), the solution was allowed to settle on a 1200 G magnetic field. After 2 hours, the absorbance of the supernatant was measured, and the separation efficiency of the regenerated Fe3O4@Zn-MOF / HBP-COOH was calculated to be 95.9% using formula (1).

[0104]

[0105]

[0106] Example 2-2

[0107] The Fe3O4@Zn-MOF / HBP-COOH prepared in Examples 1-2 was added to the algal bloom water solution (pH = 9.23) at a final concentration of 2500 mg / L. After thorough stirring (150 rpm), the solution was allowed to settle under a 2800 G magnetic field. After 2 hours, the absorbance of the supernatant was measured, and the algal bloom concentration in the supernatant was calculated using the standard curve equation. Finally, the removal rate was calculated using formula (1), and the removal rate was found to be 94.5%. After adsorption, the Fe3O4@Zn-MOF / HBP-COOH was regenerated by ultrasound, and the regeneration rate was calculated according to formula (2), which showed a regeneration rate of 97.2%. The regenerated Fe3O4@Zn-MOF / HBP-COOH was then added to the same algal bloom solution at a final concentration of 2500 mg / L. After stirring thoroughly (150 rpm), the solution was allowed to settle on a 2800 G magnetic field. After 2 hours, the absorbance of the supernatant was measured. Based on the standard curve equation, the separation efficiency of the regenerated Fe3O4@Zn-MOF / HBP-COOH was calculated to be 93.5% using formula (1).

[0108] Example 2-3

[0109] The Fe3O4@Zn-MOF / HBP-COOH prepared in Examples 1-3 was added to drilling wastewater (pH = 8.37) at a final concentration of 1500 mg / L. After thorough stirring (150 rpm), the solution was allowed to settle under a 2100 G magnetic field. After 2 hours, the absorbance of the supernatant was measured, and the bentonite concentration in the wastewater supernatant was calculated using the standard curve equation. Finally, the removal rate was calculated using formula (1), yielding a removal rate of 95.8%. After adsorption, the Fe3O4@Zn-MOF / HBP-COOH was regenerated by ultrasonication, and the regeneration rate was calculated according to formula (2), which showed a regeneration rate of 96.9%. The regenerated Fe3O4@Zn-MOF / HBP-COOH was then added to the same drilling wastewater solution at a final concentration of 1500 mg / L. After stirring thoroughly (120 rpm), the solution was allowed to settle on a 2100 G magnetic field. After 2 hours, the absorbance of the supernatant was measured. Based on the standard curve equation, the separation efficiency of the regenerated Fe3O4@Zn-MOF / HBP-COOH was calculated to be 95.4% using formula (1).

[0110] Examples 2-4

[0111] The Fe3O4@Zn-MOF / HBP-COOH prepared in Examples 1-2 was added to a methylene blue solution (concentration 100 mg / L, pH = 5.25) at a final concentration of 500 mg / L. After thorough stirring (120 rpm), the solution was allowed to settle under a 2100 G magnetic field. After 2 hours, the absorbance of the supernatant was measured, and the methylene blue concentration in the supernatant was calculated using the standard curve equation. Finally, the removal rate was calculated using formula (1), yielding a removal rate of 96.7%. After adsorption, Fe3O4@Zn-MOF / HBP-COOH was regenerated by ultrasound, and the regeneration rate was calculated according to formula (2), which showed a regeneration rate of 98.4%. The regenerated Fe3O4@Zn-MOF / HBP-COOH was then added to the same methylene blue solution at a final concentration of 100 mg / L. After stirring thoroughly (120 rpm), the solution was allowed to settle on a 2100 G magnetic field. After 2 hours, the absorbance of the supernatant was measured. Based on the standard curve equation, the separation efficiency of Fe3O4@Zn-MOF / HBP-COOH after regeneration was calculated to be 95.2% using formula (1).

[0112] Examples 2-5

[0113] The Fe3O4@Zn-MOF / HBP-COOH prepared in Examples 1-3 was added to the metallurgical wastewater solution (Cu) at a final concentration of 800 mg / L. 2+ The solution (concentration 50 mg / L, pH = 9.95) was thoroughly stirred (150 rpm) and then allowed to settle under a 2800 G magnetic field. After 2 hours, the absorbance of the supernatant was measured. Using the standard curve equation, the Cu content of the wastewater supernatant was calculated. 2+ Concentration. Finally, the removal rate was calculated using formula (1), and the removal rate was 97.8%. After adsorption, the Fe3O4@Zn-MOF / HBP-COOH was regenerated by ultrasonic method, and the regeneration rate was calculated according to formula (2), and the regeneration rate was 97.2%. The regenerated Fe3O4@Zn-MOF / HBP-COOH was added to the same metallurgical wastewater solution at a final concentration of 800 mg / L. After stirring thoroughly (150 rpm), it was allowed to settle on a 2800 G magnetic field. After 2 hours, the absorbance of the supernatant was measured. Based on the standard curve equation, the separation efficiency of Fe3O4@Zn-MOF / HBP-COOH after regeneration was calculated to be 96.3% using formula (1).

[0114] Examples 2-6

[0115] The Fe3O4@Zn-MOF / HBP-COOH prepared in Example 1-1 was added to an alkaline fuchsin dye solution (concentration 40 mg / L, pH = 9.95) at a final concentration of 400 mg / L. After thorough stirring (120 rpm), the solution was allowed to settle under a 1600 G magnetic field. After 2 hours, the absorbance of the supernatant was measured, and the concentration of alkaline fuchsin in the wastewater supernatant was calculated using the standard curve equation. Finally, the removal rate was calculated using formula (1), and the removal rate was found to be 94.7%. After adsorption, the Fe3O4@Zn-MOF / HBP-COOH was regenerated by ultrasound, and the regeneration rate was calculated according to formula (2), which showed a regeneration rate of 97.5%. The regenerated Fe3O4@Zn-MOF / HBP-COOH was then added to the same basic fuchsin dye solution at a final concentration of 400 mg / L. After stirring thoroughly (120 rpm), the solution was allowed to settle on a 1600 G magnetic field. After 2 hours, the absorbance of the supernatant was measured. Based on the standard curve equation, the separation efficiency of the regenerated Fe3O4@Zn-MOF / HBP-COOH was calculated to be 93.1% using formula (1).

[0116] Examples 2-7

[0117] The Fe3O4@Zn-MOF / HBP-COOH prepared in Examples 1-3 was added to the mining wastewater at a final concentration of 500 mg / L. 3+ The solution (concentration 100 mg / L, pH = 4.32) was thoroughly stirred (120 rpm) and then allowed to settle under a 1600 G magnetic field. After 2 hours, the absorbance of the supernatant was measured. Based on the standard curve equation, the Fe content of the wastewater supernatant was calculated. 3+ Concentration. Finally, the removal rate was calculated using formula (1), and the removal rate was 96.8%. After adsorption, the Fe3O4@Zn-MOF / HBP-COOH was regenerated by ultrasonic method, and the regeneration rate was calculated according to formula (2), and the regeneration rate was 98.5%. The regenerated Fe3O4@Zn-MOF / HBP-COOH was added to the same mining wastewater solution at a final concentration of 500 mg / L. After stirring thoroughly (120 rpm), it was allowed to settle on a 1600 G magnetic field. After 2 hours, the absorbance of the supernatant was measured. Based on the standard curve equation, the separation efficiency of Fe3O4@Zn-MOF / HBP-COOH after regeneration was calculated to be 96.1% using formula (1).

[0118] Examples 2-8

[0119] The Fe3O4@Zn-MOF / HBP-COOH prepared in Examples 1-2 was added to Rhodamine B wastewater (concentration 20 mg / L, pH = 4.05) at a final concentration of 400 mg / L. After thorough stirring (120 rpm), the solution was allowed to settle under a 1600 G magnetic field. After 2 hours, the absorbance of the supernatant was measured, and the concentration of Rhodamine B in the wastewater supernatant was calculated using the standard curve equation. Finally, the removal rate was calculated using formula (1), yielding a removal rate of 93.6%. After adsorption, the Fe3O4@Zn-MOF / HBP-COOH was regenerated by ultrasonication, and the regeneration rate was calculated according to formula (2), which showed a regeneration rate of 96.3%. The regenerated Fe3O4@Zn-MOF / HBP-COOH was then added to the same Rhodamine B wastewater solution at a final concentration of 400 mg / L. After stirring thoroughly (120 rpm), the solution was allowed to settle on a 1600 G magnetic field. After 2 hours, the absorbance of the supernatant was measured. Based on the standard curve equation, the separation efficiency of the regenerated Fe3O4@Zn-MOF / HBP-COOH was calculated to be 92.5% using formula (1).

[0120] Examples 2-9

[0121] The Fe3O4@Zn-MOF / HBP-COOH prepared in Example 1-1 was added to the crystal violet dye wastewater (concentration 30 mg / L, pH = 5.42) at a final concentration of 800 mg / L. After thorough stirring (120 rpm), the solution was allowed to settle under a 2800 G magnetic field. After 2 hours, the absorbance of the supernatant was measured, and the concentration of crystal violet in the wastewater supernatant was calculated using the standard curve equation. Finally, the removal rate was calculated using formula (1), and the removal rate was found to be 94.5%. After adsorption, the Fe3O4@Zn-MOF / HBP-COOH was regenerated by ultrasonication, and the regeneration rate was calculated according to formula (2), which showed a regeneration rate of 97.8%. The regenerated Fe3O4@Zn-MOF / HBP-COOH was then added to the same crystal violet wastewater solution at a final concentration of 400 mg / L. After stirring thoroughly (120 rpm), the solution was allowed to settle on a 2800 G magnetic field. After 2 hours, the absorbance of the supernatant was measured. Based on the standard curve equation, the separation efficiency of the regenerated Fe3O4@Zn-MOF / HBP-COOH was calculated to be 92.9% using formula (1).

[0122] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention in any way. All equivalent transformations or modifications made in accordance with the essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing hyperbranched magnetically modified MOFs-based composite materials, characterized in that, Includes the following steps: S1. Preparation of Zn-MOF S11. Sodium hydroxide, pyromellitic acid, N,N dimethylformamide, ethanol and deionized water are mixed evenly in a mass ratio of 1:1.75:30:200:420 and then ultrasonically assembled in a constant temperature water bath at 30°C to obtain mixed solution A. S12. Add zinc acetate dihydrate and sodium hydroxide to mixed solution A at a mass ratio of (1~6):1 and react fully. Centrifuge and wash with water and alcohol three times each, and then dry under vacuum to obtain Zn-MOF. S2. Preparation of magnetic Zn-MOF The magnetic Fe3O4 and the Zn-MOF prepared in step S1 were dispersed in an appropriate amount of ethanol solution at a mass ratio of 1:(1~10). The mixture was first stirred evenly in a water bath at 30°C, then ultrasonically assembled, and finally dried to obtain the magnetic Zn-MOF material. S3. Preparation of carboxyl-terminated hyperbranched polymers S31. Mix diethanolamine and methanol in a volume ratio of 1:3 to 3:1, and stir at room temperature until the diethanolamine is completely dissolved to obtain mixed solution B. S32. Take an appropriate amount of methyl acrylate, slowly add the methyl acrylate dropwise to the mixed solution B, and mix thoroughly. Then react at 35°C for 4 hours and at 85°C for 1.5 hours to obtain mixed solution C. S33. Trimethylolpropane and p-toluenesulfonic acid were added to mixed solution C at a molar ratio of (50~80):

1. The mixture was first heated at 120℃ for 3 hours, and then heated at 100℃ for 1 hour to obtain mixed solution D. S34. Maleic anhydride and p-toluenesulfonic acid were added to mixed solution D in a molar ratio of 20:1 to 60:1, and reacted at 80°C for 2.5 h and 130°C for 12 h, respectively, to obtain a carboxyl-terminated hyperbranched polymer. S4, Synthetic hyperbranched magnetically modified MOFs-based composite materials The magnetic Zn-MOF prepared in step S2 and the carboxyl-terminated hyperbranched polymer prepared in step S3 are dissolved in a mixed solution of acetic acid and nitric acid at a mass ratio of 1:2 to 4:

1. The resulting solution is ultrasonically assembled, repeatedly washed with deionized water, and then thoroughly dried to obtain hyperbranched magnetically modified MOFs-based composite material. In the hyperbranched magnetically modified MOFs-based composite material, Zn-MOF and HBP-COOH are wrapped on the surface of Fe3O4 to form a ternary core-shell structure, wherein the magnetic core is Fe3O4, the middle layer is Zn-MOF, and the outer shell is a carboxyl-terminated hyperbranched polymer.

2. The method for preparing a hyperbranched magnetically modified MOFs-based composite material according to claim 1, characterized in that, In step S32, the volume ratio of methyl acrylate to mixed solution B is 1:2 to 4:

1.

3. A hyperbranched magnetically modified MOFs-based composite material, characterized in that, It is prepared by the method described in any one of claims 1-2.

4. An application of the hyperbranched magnetically modified MOFs-based composite material as described in claim 3, characterized in that, Applications in the removal of color from water bodies.

5. The application of the hyperbranched magnetically modified MOFs-based composite material according to claim 4, characterized in that, Hyperbranched magnetically modified MOFs-based composite materials were added to high-chroma wastewater at a final concentration of 20 mg / L to 2500 mg / L. The mixture was continuously stirred at a temperature of 20℃ to 60℃ and a speed of 80 rpm to 150 rpm to remove color from the water. The hyperbranched magnetically modified MOFs-based composite materials were then regenerated under the action of a permanent magnet. The regenerated hyperbranched magnetically modified MOFs-based composite materials can be used again to remove color from water.

6. The application of the hyperbranched magnetically modified MOFs-based composite material according to claim 5, characterized in that, The high-chroma wastewater includes, but is not limited to, wastewater containing dyes, metallurgical wastewater, drilling wastewater, mining wastewater, and water bodies with algal blooms.

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