Superhydrophobic melamine sponge for dye degradation and emulsion purification and method of making same

Abstract

The application belongs to the technical field of wastewater treatment composite materials, and particularly relates to a super-hydrophobic melamine sponge for dye degradation and emulsion purification and a preparation method thereof. Ag-MOF and hydroxyl zinc fluoride nanoparticles are synthesized through a simple hydrothermal method, and the two kinds of nanoparticles are loaded onto the melamine sponge by using polydimethylsiloxane to obtain super-hydrophobic super-oil-wetting Ag-MOF@hydroxyl zinc fluoride@polydimethylsiloxane@melamine sponge, the hydrophobic angle of which is as high as 155.3°, and the adsorption capacity reaches 54.6-109.7g / g. Meanwhile, the super-hydrophobic super-oil-wetting Ag-MOF@hydroxyl zinc fluoride@polydimethylsiloxane@melamine sponge also shows excellent oil-water separation capacity (99%), dye degradation capacity (99%) and emulsion purification capacity (98%). Therefore, the modified sponge prepared by the application has a wide application prospect in the field of wastewater treatment.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology for wastewater treatment, specifically relating to a superhydrophobic melamine sponge for dye degradation and emulsion purification and its preparation method. Background Technology

[0002] Water pollution is currently a major global concern, causing enormous economic losses and significant damage to ecosystems. Therefore, effectively removing oils, organic solvents, and organic dyes from wastewater is urgently needed. Compared to other wastewater treatment technologies, adsorption is considered a highly efficient, low-cost, and simple method. Among various adsorption materials, sponges are widely used due to their porous structure, high adsorption capacity, reusability, and ease of recycling. Furthermore, sponges can be loaded with other nanoparticles through physical blending or chemical modification, thereby greatly improving their adsorption performance.

[0003] Nanoscale metal-organic frameworks (MOFs) possess characteristics such as high porosity, high specific surface area, and high stability, thus occupying an important position in the field of adsorption. Currently, many studies have successfully prepared MOF-based sponges for the removal of organic pollutants from wastewater. However, most sponges exhibit low adsorption capacity and slow adsorption rates for organic dyes. Furthermore, while most superhydrophobic sponges can adsorb insoluble oils from oily wastewater, they cannot treat soluble dyes, which limits their applications. Therefore, developing superhydrophobic sponges that can not only adsorb oils and organic solvents but also efficiently degrade dyes is of great significance. Summary of the Invention

[0004] To address the technical problems identified in the background section, this invention provides a superhydrophobic melamine sponge for dye degradation and emulsion purification. Using melamine as a substrate, Ag-MOF and zinc hydroxyfluoride nanoparticles were synthesized via a simple hydrothermal method. The two nanoparticles were then bonded to the melamine sponge using polydimethylsiloxane, a low surface energy material. This successfully prepared a superhydrophobic and superoleophilic Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge, achieving efficient oil-water separation, dye degradation, and emulsion purification. It can be widely used in wastewater treatment.

[0005] The hydrothermal synthesis method for Ag-MOF nanoparticles is as follows: 1.64 g of 2-methylimidazole is dissolved in 25 mL of ammonium hydroxide solution to obtain solution A; 0.58 g of silver nitrate is dissolved in 3 mL of deionized water to obtain solution B. Solution B is slowly poured into solution A, stirred for 30 min, and then transferred to a high-pressure reactor. After reacting at 100 °C for 24 h, the mixture is centrifuged, and the resulting solid is dried at 80 °C for 12 h to obtain Ag-MOF nanoparticles.

[0006] The hydrothermal synthesis method for zinc hydroxyfluoride nanoparticles is as follows: 0.0891 g alanine and 0.6585 g zinc acetate dihydrate are dissolved in 25 ml deionized water and stirred for 30 min. Then, 0.1782 g sodium hexafluorosilicate is added to the mixed solution and stirred for 30 min. The mixture is then transferred to a high-pressure reactor and reacted at 120 °C for 12 h. After centrifugation, the obtained solid is dried at 70 °C for 4 h to obtain zinc hydroxyfluoride nanoparticles.

[0007] The method for preparing superhydrophobic and superoleophilic Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge is as follows: A certain amount of Ag-MOF, zinc hydroxyfluoride, and polydimethylsiloxane are added to 50 mL of n-hexane solution at a certain mass ratio. After stirring for 30 min, four melamine sponges (volume: 1×1×1 cm) that have been washed with ethanol and deionized water are added to the mixed solution. 3 After stirring evenly, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@hydroxyzinc fluoride@polydimethylsiloxane@melamine sponge.

[0008] The mass ratio of Ag-MOF, zinc hydroxyfluoride and polydimethylsiloxane is 0.5:1:6-1:1:10, and the sponge stirring time is 1-4 hours.

[0009] The superhydrophobic melamine sponge of the present invention is used for dye degradation and emulsion purification.

[0010] The beneficial effects of this invention are as follows:

[0011] 1. The superhydrophobic melamine sponge prepared by this invention has the characteristics of simple preparation method, green and environmentally friendly preparation process and readily available raw materials.

[0012] 2. Ag-MOF has uniform micropore size and high specific surface area (676m²). 2 / g), zinc hydroxyfluoride possesses optimized geometry and a large specific surface area (271m²) of nanosheet-assembled microspheres. 2 / g), combining the two and loading them onto melamine sponge is beneficial for promoting rapid adsorption of dyes.

[0013] 3. The superhydrophobic melamine sponge prepared by this invention exhibits excellent comprehensive performance. Even with a hydrophobic angle of 155.3°, its adsorption capacity still reaches 54.6-109.7 g / g. It also demonstrates excellent oil-water separation capability (99%) and emulsion purification capability (98%). Furthermore, it possesses highly efficient dye degradation capability under conditions of efficient oil-water separation, achieving a removal rate of up to 99% for malachite green. Therefore, the multifunctional modified sponge prepared by this invention has broad application prospects in the field of wastewater treatment. Attached Figure Description

[0014] Figure 1 The image shows a SEM image of the superhydrophobic melamine sponge obtained in Example 1.

[0015] Figure 2 The XRD patterns of Ag-MOF and zinc hydroxyfluoride in Example 1 are shown.

[0016] Figure 3 The image shows the SEM images of Ag-MOF and zinc hydroxyfluoride in Example 1.

[0017] Figure 4 The image shows the water contact angle of the superhydrophobic melamine sponge obtained in Example 1.

[0018] Figure 5 The image shows the morphology of a superhydrophobic melamine sponge obtained in Example 1 and its cross-section, with water droplets placed on the original melamine sponge.

[0019] Figure 6 The images show the original melamine sponge and the superhydrophobic and superoleophilic melamine sponge obtained in Example 1 in water.

[0020] Figure 7 This is a comparison chart of the adsorption capacity of the superhydrophobic melamine sponge obtained in Example 1 for different organic solvents or oils.

[0021] Figure 8 This is a comparison chart showing the separation efficiency of the superhydrophobic melamine sponge obtained in Example 1 for different organic solvent / water mixtures.

[0022] Figure 9 This is a comparison chart showing the adsorption capacity of the superhydrophobic melamine sponge obtained in Example 1 for n-hexane and chloroform after 10 cycles of adsorption.

[0023] Figure 10 This is a comparison chart of the transmittance of the superhydrophobic melamine sponge obtained in Example 1 before and after purification of four emulsions: hexane in water, dichloromethane in water, water in hexane, and water in dichloromethane.

[0024] Figure 11 This is a comparison chart of the removal rates of different dyes on the superhydrophobic melamine sponge obtained in Example 1.

[0025] Figure 12 This is a comparison chart showing the removal rates of malachite green dye at different concentrations by the superhydrophobic melamine sponge obtained in Example 1.

[0026] Figure 13 The graph shows a comparison of the removal rates of malachite green at a concentration of 10 mg / L within 1 hour between the original melamine sponge and the modified sponges obtained in Example 1, Comparative Example 1, and Comparative Example 2.

[0027] Figure 14This is a comparison chart of the hydrophobic angle and n-hexane adsorption capacity of the modified sponges obtained in Example 1, Comparative Example 1, and Comparative Example 2. Detailed Implementation

[0028] The present invention will be further described below with reference to embodiments, but is not limited thereto. Example 1

[0029] (1) 1.64 g of 2-methylimidazole was dissolved in 25 mL of ammonium hydroxide solution to obtain solution A; 0.58 g of silver nitrate solution was dissolved in 3 mL of deionized water to obtain solution B. Solution B was slowly poured into solution A, stirred for 30 min, and then transferred to a high-pressure reactor. After reacting at 100 °C for 24 h, the mixture was centrifuged. The resulting solid was dried at 80 °C for 12 h to obtain Ag-MOF nanoparticles with a specific surface area of ​​676 m². 2 / g.

[0030] (2) Dissolve 0.0891 g alanine and 0.6585 g zinc acetate dihydrate in 25 ml of deionized water. After stirring for 30 min, add 0.1782 g sodium hexafluorosilicate to the mixed solution and stir for another 30 min. Then transfer the mixture to a high-pressure reactor and react at 120 °C for 12 h. After centrifugation, dry the resulting solid at 70 °C for 4 h to obtain zinc hydroxyfluoride nanoparticles with a specific surface area of ​​271 m². 2 / g.

[0031] (3) Add 0.05g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.3g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After stirring for 3 hours, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0032] Figure 2 The XRD characterization results of Ag-MOF and zinc hydroxyfluoride are shown. In the XRD pattern of Ag-MOF, prominent peaks are observed at 2θ values ​​of 16.9°, 28.0°, 28.8°, 39.4°, 44.3°, and 65.4°, confirming the successful preparation of highly crystalline Ag-MOF. In the XRD pattern of zinc hydroxyfluoride, all diffraction peaks point to the orthorhombic phase of zinc hydroxyfluoride, and no other diffraction peaks caused by impurities were observed. Therefore, the prepared zinc hydroxyfluoride microspheres possess high crystallinity and high purity.

[0033] Figure 3The images show SEM images of Ag-MOF and zinc hydroxyfluoride. As can be seen, both Ag-MOF and zinc hydroxyfluoride are nanoparticles. Ag-MOF is formed by clusters of nanoparticles, while zinc hydroxyfluoride is composed of petal-shaped microspheres assembled from nanosheets. Both possess abundant porous structures, which facilitates the adsorption of more dye molecules.

[0034] (i) Further study on the hydrophobic properties, saturated adsorption capacity, oil-water separation efficiency and reusability of the superhydrophobic melamine prepared in this invention to evaluate the oil-water selectivity of the modified sponge.

[0035] (1) Hydrophobic properties

[0036] Figure 4 The hydrophobic angle diagram shows that Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge has a hydrophobic angle of up to 155.3°. When deionized water droplets are placed on the surfaces of the original melamine sponge and the modified sponge, the water droplets on the original sponge are quickly absorbed, while the water droplets on the modified sponge remain spherical, and the water droplets on its cross-section also remain spherical. Figure 5 When the original sponge and the modified sponge are placed in deionized water at the same time, the original sponge sinks to the bottom, while the modified sponge floats on the surface. Figure 6 Therefore, the superhydrophobic melamine sponge prepared by this invention has excellent superhydrophobic properties.

[0037] (2) Adsorption capacity for oily substances and organic solvents

[0038] like Figure 7 As shown, Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge has an adsorption capacity of 54.6 (n-hexane)-109.7 (chloroform) g / g, exhibiting excellent adsorption capacity.

[0039] (3) Oil-water separation capacity test

[0040] like Figure 8 As shown, the modified sponge achieved separation efficiencies of 99.2%, 99.8%, 99.7%, 99.7%, 99.5%, and 99.7% for mixtures of chloroform / water, n-hexane / water, dichloromethane / water, benzene / water, toluene / water, and petroleum ether / water, respectively, with oil-water separation reaching 99%. This demonstrates that the superhydrophobic melamine sponge prepared in this invention has excellent oil-water separation performance.

[0041] (4) Reusability test

[0042] Reusability is of great significance in practical applications. The reusability of Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge was studied through cyclic adsorption-compression experiments. Figure 9As shown, after 10 cycles, the modified sponge still retains adsorption capacities of 51.6 g / g for hexane and 104.5 g / g for chloroform, with adsorption capacity decreasing by only about 5%. Therefore, the superhydrophobic melamine sponge prepared in this invention has excellent reusability.

[0043] (II) Stable, miscible emulsions are more difficult to separate than immiscible oil-water mixtures. The purification capabilities of modified sponges for emulsions containing chloroform (water-encapsulated), hexane (water-encapsulated), and toluene (water-encapsulated) were investigated experimentally. The specific experimental steps are as follows:

[0044] Two oil-in-water emulsions were prepared by mixing deionized water and n-hexane / dichloromethane at a volume ratio of 8:1 and stirring at high speed for 6 h (160 mL deionized water, 20 mL n-hexane / dichloromethane). Then, deionized water and n-hexane / dichloromethane were mixed at a volume ratio of 1:8 and sonicated for 30 min. Finally, 0.08 g of surfactant Span80 was added (20 mL deionized water, 160 mL n-hexane / dichloromethane), and the mixture was stirred for 6 h to obtain two water-in-oil emulsions. A modified sponge was immersed in the four emulsions, and the transmittance of the four emulsions before and after separation was measured using a UV spectrophotometer. Figure 10 As shown, the transmittance of each emulsion after purification by the modified sponge reached over 91%. Therefore, the modified sponge prepared in this invention has a highly efficient emulsion purification capability.

[0045] (III) Most colored dyes are toxic and difficult to biodegrade due to their complex molecular structure. The removal rate of different dyes (all at a concentration of 10 mg / L) by modified sponges within 150 min was investigated experimentally. For example... Figure 11 As shown, the modified sponge exhibits strong adsorption for cationic dyes such as malachite green, achieving a removal rate of 99.3% for malachite green. Further investigation was conducted to determine the removal rate of different concentrations of malachite green by the modified sponge within 150 minutes. Figure 12 As shown, within 150 min, the modified sponge achieved removal rates of 99.3%, 98.5%, 94.5%, 93.9%, and 93.4% for malachite green concentrations of 5 mg / L, 10 mg / L, 15 mg / L, 20 mg / L, and 25 mg / L, respectively, with all removal rates exceeding 90%. Example 2

[0046] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0047] (2) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0048] (3) Add 0.05g Ag-MOF, 0.025g zinc hydroxyfluoride and 0.3g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 ethanol and deionized water-washed melamine sponges (volume: 1×1×1cm) to the mixed solution. 3 After stirring for 3 hours, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0049] The modified melamine sponge has a hydrophobic angle of 152.6°, an adsorption capacity of 52.8 g / g for n-hexane, and a separation efficiency of 97.5% for n-hexane / water mixture. Example 3

[0050] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0051] (2) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0052] (3) Add 0.025g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.3g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 ethanol and deionized water-washed melamine sponges (volume: 1×1×1cm) to the mixed solution. 3 After stirring for 3 hours, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0053] The modified melamine sponge has a hydrophobic angle of 151.9°, an adsorption capacity of 52.4 g / g for n-hexane, and a separation efficiency of 96.8% for n-hexane / water mixture. Example 4

[0054] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0055] (2) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0056] (3) Add 0.05g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.1g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 ethanol and deionized water-washed melamine sponges (volume: 1×1×1cm) to the mixed solution. 3 After stirring for 3 hours, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0057] The modified melamine sponge has a hydrophobic angle of 151.4°, an adsorption capacity of 53.4 g / g for n-hexane, and a separation efficiency of 97.2% for n-hexane / water mixture. Example 5

[0058] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0059] (2) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0060] (3) Add 0.05g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.2g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After stirring for 3 hours, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0061] The modified melamine sponge has a hydrophobic angle of 152.9°, an adsorption capacity of 54.1 g / g for n-hexane, and a separation efficiency of 97.9% for n-hexane / water mixture. Example 6

[0062] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0063] (2) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0064] (3) Add 0.05g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.4g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After stirring for 3 hours, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0065] The modified melamine sponge has a hydrophobic angle of 154.2°, an adsorption capacity of 53.2 g / g for n-hexane, and a separation efficiency of 98.6% for n-hexane / water mixture. Example 7

[0066] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0067] (2) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0068] (3) Add 0.05g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.5g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution.3 After stirring for 3 hours, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0069] The modified melamine sponge has a hydrophobic angle of 155.0°, an adsorption capacity of 52.9 g / g for n-hexane, and a separation efficiency of 99.1% for n-hexane / water mixture. Example 8

[0070] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0071] (2) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0072] (3) Add 0.05g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.3g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After stirring for 1 hour, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0073] The modified melamine sponge has a hydrophobic angle of 151.9°, an adsorption capacity of 50.2 g / g for n-hexane, and a separation efficiency of 97.4% for n-hexane / water mixture. Example 9

[0074] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0075] (2) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0076] (3) Add 0.05g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.3g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After stirring for 2 hours, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0077] The modified melamine sponge has a hydrophobic angle of 153.9°, an adsorption capacity of 53.8 g / g for n-hexane, and a separation efficiency of 98.5% for n-hexane / water mixture. Example 10

[0078] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0079] (2) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0080] (3) Add 0.05g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.3g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After stirring for 4 hours, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0081] The modified melamine sponge has a hydrophobic angle of 154.8°, an adsorption capacity of 52.4 g / g for n-hexane, and a separation efficiency of 99.1% for n-hexane / water mixture.

[0082] Comparative Example 1

[0083] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0084] (2) Add 0.1g Ag-MOF and 0.3g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After stirring for 3 hours, Ag-MOF@polydimethylsiloxane@melamine sponge was obtained by curing at 180℃ for 1 hour.

[0085] The modified melamine sponge has a hydrophobic angle of 151.5°, an adsorption capacity of 46.9 g / g for n-hexane, a separation efficiency of 97.4% for n-hexane / water mixture, and a removal rate of 96.5% for 10 mg / L malachite green within 60 min.

[0086] Comparative Example 2

[0087] (1) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0088] (2) Add 0.1g of zinc hydroxyfluoride and 0.3g of polydimethylsiloxane to 50mL of n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After stirring for 3 hours, the mixture was cured at 180°C for 1 hour to obtain hydroxyl zinc fluoride@polydimethylsiloxane@melamine sponge.

[0089] The modified melamine sponge has a hydrophobic angle of 152.0°, an adsorption capacity of 49.1 g / g for n-hexane, a separation efficiency of 97.6% for n-hexane / water mixture, and a removal rate of 89.8% for 10 mg / L malachite green within 60 min.

[0090] Comparative Example 3

[0091] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0092] (2) The preparation method of zinc hydroxyfluoride nanoparticles is the same as in Example 1.

[0093] (3) Add 0.05g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.3g polydimethylsiloxane to 50mL n-hexane solution, sonicate for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After ultrasonic treatment for 3 hours, Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge was obtained by curing at 180℃ for 1 hour.

[0094] The modified melamine sponge has a hydrophobic angle of 153.2°, an adsorption capacity of 49.6 g / g for n-hexane, a separation efficiency of 98.2% for n-hexane / water mixture, and a removal rate of 93.4% for 10 mg / L malachite green within 60 min.

[0095] Comparative Example 4

[0096] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0097] (2) Dissolve 0.2195g of zinc acetate dihydrate in 25mL of ethylene glycol, stir for 30min, add 0.3299g of sodium tungstate dihydrate, stir the mixture for 30min, transfer it to a high-pressure reactor, react at 150℃ for 12h, centrifuge, and dry the obtained solid at 70℃ for 4h to obtain zinc tungstate nanoparticles.

[0098] (3) Add 0.05g Ag-MOF, 0.05g zinc tungstate and 0.3g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After stirring for 3 hours, Ag-MOF@zinc tungstate@polydimethylsiloxane@melamine sponge was obtained by curing at 180℃ for 1 hour.

[0099] The modified melamine sponge has a hydrophobic angle of 151.8°, an adsorption capacity of 50.2 g / g for n-hexane, a separation efficiency of 97.5% for n-hexane / water mixture, and a removal rate of 78.5% for 10 mg / L malachite green within 60 min.

[0100] Comparative Example 5

[0101] (1) The preparation method of Ag-MOF nanoparticles is the same as in Example 1.

[0102] (2) Dissolve 0.0891g alanine and 0.6585g zinc acetate dihydrate in 25ml deionized water, stir for 30min, add 0.1782g sodium hexafluorosilicate to the mixed solution, stir for 30min, transfer to a high-pressure reactor, react at 120℃ for 6h, centrifuge, and dry the obtained solid at 70℃ for 4h to obtain zinc hydroxyfluoride nanoparticles.

[0103] (3) Add 0.05g Ag-MOF, 0.05g zinc hydroxyfluoride and 0.3g polydimethylsiloxane to 50mL n-hexane solution, stir for 30min, and then add 4 melamine sponges (volume: 1×1×1cm) that have been washed with ethanol and deionized water to the mixed solution. 3 After stirring for 3 hours, the mixture was cured at 180℃ for 1 hour to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge.

[0104] The modified melamine sponge has a hydrophobic angle of 153.8°, an adsorption capacity of 48.8 g / g for n-hexane, a separation efficiency of 98.6% for n-hexane / water mixture, and a removal rate of 90.6% for 10 mg / L malachite green within 60 min.

[0105] The embodiments described above are merely preferred examples to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A superhydrophobic melamine sponge, characterized in that, The superhydrophobic melamine sponge uses melamine as a substrate and loads Ag-MOF nanoparticles and zinc hydroxy fluoride nanoparticles onto the melamine sponge using polydimethylsiloxane to obtain a superhydrophobic Ag-MOF@zinc hydroxy fluoride@polydimethylsiloxane@melamine sponge. The method for preparing the zinc hydroxyfluoride nanoparticles is as follows: 0.0891 g alanine and 0.6586 g zinc acetate dihydrate are dissolved in 25 mL of deionized water, stirred for 30 min, and then 0.1782 g sodium hexafluorosilicate is added. After stirring until completely dissolved, the mixture is transferred to a high-pressure reactor. After the reaction is complete, the mixture is centrifuged and dried to obtain zinc hydroxyfluoride nanoparticles. The reaction in the high-pressure reactor was carried out at 120°C for 12 hours, and the drying was carried out at 70°C for 4 hours. The mass ratio of Ag-MOF, zinc hydroxyfluoride, and polydimethylsiloxane is 0.5:1:6-1:1:10; The preparation method of the superhydrophobic melamine sponge is as follows: Ag-MOF, zinc hydroxyfluoride and polydimethylsiloxane are added to n-hexane solution in a mass ratio, stirred for 30 min, and then the pretreated melamine sponge is added to the mixed solution. After stirring evenly, it is cured to obtain Ag-MOF@zinc hydroxyfluoride@polydimethylsiloxane@melamine sponge. The superhydrophobic melamine sponge is used for malachite green dye degradation and emulsion purification.

2. The superhydrophobic melamine sponge as described in claim 1, characterized in that, The preparation method of Ag-MOF nanoparticles is as follows: 2-methylimidazole is dissolved in ammonium hydroxide solution to obtain solution A; silver nitrate is dissolved in deionized water to obtain solution B; solution B is added to solution A; after stirring for 30 min, the mixture is transferred to a high-pressure reactor; after the reaction is complete, it is centrifuged and dried to obtain Ag-MOF nanoparticles.

3. The superhydrophobic melamine sponge as described in claim 2, characterized in that, The amount of 2-methylimidazole used was 1.64 g, the amount of ammonium hydroxide was 25 mL, the amount of silver nitrate was 0.58 g, and the amount of deionized water was 3 mL. The reaction in the high-pressure reactor was maintained at 100 °C for 24 h, and the drying was carried out at 80 °C for 12 h.

4. The superhydrophobic melamine sponge as described in claim 1, characterized in that: The pretreated melamine sponge was obtained by sonicating in ethanol and deionized water for 1 hour respectively, followed by drying at 60°C. Each sponge had a volume of 1*1*1 cm. 3 The number of units invested is 4.

5. The superhydrophobic melamine sponge as described in claim 1, characterized in that: The time for adding the sponge and stirring evenly is 1-4 hours, and the curing is carried out at 180℃ for 1 hour.

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