Multifunctional super-hydrophobic melamine sponge based on core-shell metal organic framework structure as well as preparation method and application of multifunctional super-hydrophobic melamine sponge

Abstract

The invention belongs to the field of high-performance oil-water separation composite materials, and particularly relates to a multifunctional super-hydrophobic melamine sponge based on a core-shell metal organic framework structure as well as a preparation method and application of the multifunctional super-hydrophobic melamine sponge. The multifunctional super-hydrophobic melamine sponge is prepared by coating the core-shell structure copper sulphide coated CuFe-MOF, polyvinyl alcohol and octadecyl trichlorosilane on a melamine sponge. The prepared sponge shows excellent hydrophobicity and efficient oil-water separation capacity, the water contact angle of the sponge is as high as 157.4 degrees, and the oil-water separation efficiency can still be maintained at 98.9% after 20 times of circulating oil absorption. The temperature of the sponge can be rapidly increased to 112.5 DEG C under simulated sunlight irradiation, and the adsorption capacity of thickened oil is remarkably improved. And the sponge also has the capability of catalyzing a photo-Fenton reaction, and can effectively adsorb pollutants in seawater. The sponge provided by the invention provides an environment-friendly and efficient new scheme for treating viscosity reduction and magnetic drive oil absorption of high-viscosity crude oil.

Description

Technical Field

[0001] The present invention belongs to the field of high-performance oil-water separation composite materials, and particularly relates to a multifunctional superhydrophobic melamine sponge based on a core-shell metal-organic framework structure, a preparation method thereof, and an application thereof. Background Art

[0002] Oil spill accidents occur frequently, causing irreversible pollution to the environment. And due to the low fluidity and high viscosity of viscous crude oil, the adsorption of viscous oil still poses challenges. Conventional oil spill remediation strategies include mechanical skimming, chemical dispersion, in-situ burning, and microbial degradation. These methods have certain limitations, are prone to secondary pollution, and have low recovery efficiency. Therefore, new oil spill treatment methods need to be explored. In recent years, various oil adsorption materials have come into the public eye, such as polyurethane sponges, melamine sponges, aerogels, etc., which have been prepared into excellent oil-absorbing materials. However, it is difficult for viscous oil to be adsorbed into the internal structure of conventional porous adsorption materials, which limits the practical application of porous oil-absorbing materials.

[0003] Increasing the temperature is the simplest method to significantly reduce the viscosity of crude oil. Inspired by this concept, some studies have achieved the viscosity reduction of heavy oil through electrothermal means. However, there are certain potential safety hazards and energy waste in long-term power supply near seawater. Therefore, photothermal viscosity reduction is a more promising and environmentally friendly viscosity reduction method. At present, some studies have achieved the coating of photothermal components on the substrate, converting the solar light energy into heat energy to realize the recovery of viscous oil. However, complex processes and chemical reagents harmful to the environment are involved in these materials. Therefore, it is of great significance to develop a more feasible and effective method for preparing photothermal hydrophobic / oleophilic adsorbents.

[0004] Among many candidate materials, metal-organic framework compounds (MOFs) and metal sulfides have attracted much attention due to their unique physical and chemical properties, but they still have some limitations in practical applications.

[0005] MOFs have the advantages of high specific surface area, high porosity, and strong structural designability. Their diverse pore sizes and pore structures can meet the size and adsorption requirements of different adsorbates, and the abundant functional groups and active sites can have specific interactions with the adsorbates, thereby achieving efficient adsorption. However, MOF materials also have some deficiencies. First of all, their stability is poor. Many MOFs are prone to structural collapse or decomposition in water or organic solvents, and their chemical stability is poor, being sensitive to acids, alkalis, water vapor, air, etc., which limits their service life and application scope in practical applications. Secondly, the adsorption selectivity of MOFs needs to be improved. In a complex adsorption system, it is easily interfered by impurity molecules, affecting the adsorption effect on the target substance. Moreover, the preparation cost of MOF materials is relatively high. The synthesis process often requires strict condition control, such as high temperature, high pressure, etc., and the yield is low, making it difficult to meet the needs of large-scale industrial applications.

[0006] Metal sulfides have unique physical and chemical properties, such as high specific surface area, abundant active sites, and adjustable band gaps, etc., which make them show good application prospects in the adsorption field. They have strong adsorption ability for certain specific heavy metal ions or organic substances, and some metal sulfides have certain magnetism, which is convenient for separation from the solution after adsorption. However, there are also some problems with metal sulfides. Their stability is insufficient, and in a complex chemical environment or during long-term use, phenomena such as aggregation, oxidation, or dissolution are likely to occur, resulting in a decline in adsorption performance. In addition, the preparation process of metal sulfides is complex and often requires strict control of conditions such as temperature, pressure, and reaction time. It is difficult to achieve large-scale and low-cost production during the preparation process. Moreover, metal sulfide nanoparticles are prone to aggregation, resulting in a decrease in specific surface area and active sites, thus affecting their adsorption performance. To inhibit aggregation, various additives usually need to be added or special preparation methods need to be adopted, but this also increases the preparation cost and process difficulty to a certain extent.

[0007] In view of the above deficiencies of MOFs and metal sulfides in the field of adsorption materials, developing new preparation methods, modification means, and composite material systems to improve their properties such as stability, adsorption selectivity, and adsorption capacity is of great significance for promoting the development and application of adsorption materials. Summary of the Invention

[0008] To solve the environmental protection and cleaning problems after the leakage of high-viscosity crude oil, the present invention provides a multifunctional superhydrophobic melamine sponge for high-viscosity oil-water separation and organic dye degradation and its preparation method. Using the melamine sponge as the substrate, by coating the core-shell structured copper sulfide@CuFe-MOF nanoparticles on the sponge surface, utilizing its photothermal conversion characteristics and magnetism, combined with polyvinyl alcohol (PVA) as the binder and octadecyltrichlorosilane (OTS) as the hydrophobic agent, a superhydrophobic octadecyltrichlorosilane / copper sulfide@CuFe-MOF / melamine sponge is successfully constructed. This sponge exhibits excellent superhydrophobic performance (the water contact angle is as high as 157.4°), efficient oil-water separation ability (the separation efficiency exceeds 99%), and can rapidly heat up to 112.5°C under simulated sunlight irradiation, significantly improving the adsorption capacity for heavy oil. In addition, this sponge also has the ability to catalyze the photo-Fenton reaction to degrade organic dyes, realizing the multifunctional integration of high-viscosity oil-water separation, emulsion purification, and organic pollutant degradation, and has broad application prospects.

[0009] The preparation method of the multifunctional superhydrophobic melamine sponge based on the core-shell metal-organic framework structure mainly includes the following steps:

[0010] (1) Dissolve copper nitrate hydrate and thiourea in ethylene glycol, then add polyvinylpyrrolidone (PVP), stir evenly and perform ultrasonic treatment. Subsequently, transfer the mixture to a high-pressure reactor and react at 180 °C for 4 h. After cooling to room temperature, collect the product by centrifugation, wash it with deionized water and ethanol, and then disperse the obtained nanoparticles in a water / ethanol solution to obtain a copper sulfide-PVP composite dispersion.

[0011] The mass ratio of polyvinylpyrrolidone to copper nitrate hydrate is: 1.39 - 1.56:1.63.

[0012] (2) Dissolve ferric chloride hexahydrate and copper chloride dihydrate in ethylene glycol, then add sodium acetate and polyethylene glycol, stir evenly and transfer the mixture to a high-pressure reactor and react at 200 °C for 8 h. After the reaction is completed, collect the product by centrifugation, wash it with deionized water and ethanol, and dry it to obtain a CuFe2O4 precursor.

[0013] (3) Disperse the copper sulfide-PVP composite obtained in step (1), the CuFe2O4 precursor obtained in step (2), and trimesic acid (H3BTC) in a mixed solution of water and ethanol. After ultrasonic treatment, transfer the mixture to a high-pressure autoclave lined with polytetrafluoroethylene and react at 150 °C for 12 h. After the reaction is completed, collect the product by centrifugation, wash it with deionized water and ethanol, and finally dry it under vacuum at 60 °C to obtain core-shell structured copper sulfide@CuFe-MOF.

[0014] Among them, the volume-mass ratio of the copper sulfide-PVP dispersion: CuFe2O4 precursor: trimesic acid is 5 mL: 0.15 - 0.84 g: 0.45 - 0.74 g.

[0015] (4) Dissolve polyvinyl alcohol (PVA) in deionized water, stir evenly and add copper sulfide

[0016] @CuFe-MOF powder, perform ultrasonic treatment for 0.5 - 2.5 h, then immerse it in 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonic treatment for 0.5 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide@CuFe-MOF / melamine sponge.

[0017] Among them, the concentration of polyvinyl alcohol in deionized water is 0.17 - 0.66 g / 50 mL; the mass ratio of polyvinyl alcohol to copper sulfide@CuFe-MOF is 0.5 - 2:1.

[0018] (5) Octadecyltrichlorosilane (OTS) was dissolved in n - hexane. After ultrasonic treatment for 30 min, it was immersed in the copper sulfide@CuFe - MOF / melamine sponge obtained in step (4), and ultrasonic treatment was continued for 30 - 60 min. Finally, it was dried at 80 °C to obtain the final super - hydrophobic octadecyltrichlorosilane / copper sulfide@CuFe - MOF / melamine sponge.

[0019] Among them, the concentration of octadecyltrichlorosilane in n - hexane was 0.4 - 1.2 mL / 50 mL.

[0020] The multifunctional super - hydrophobic melamine sponge based on the core - shell metal - organic framework structure prepared by the above method is used for high - viscosity oil - water separation, emulsion purification, and catalytic degradation of organic dyes.

[0021] Among them, high - viscosity oil - water separation includes the adsorption of methyl silicone oil, castor oil, or pump oil; catalytic degradation of organic dyes includes the degradation of methylene blue, methyl orange, rhodamine B, or crystal violet.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. For the first time, the present invention integrates magnetic - drive control, core - shell structure - assisted photothermal conversion, catalytic photo - Fenton reaction for degrading organic dyes, and super - hydrophobic / super - oleophilic properties into a single melamine sponge substrate. Through the design of the core - shell structure of copper sulfide@CuFe - MOF, the synergistic enhancement of photothermal effect and catalytic activity is realized. At the same time, the introduction of magnetic components (CuFe - MOF) endows the material with magnetic response ability, solving the problems of single - function of traditional oil - absorbing materials and difficulty in adapting to complex environments.

[0024] 2. The present invention innovatively constructs a copper sulfide@CuFe - MOF core - shell heterojunction. Through the energy - band matching of copper sulfide (strong near - infrared absorption) and CuFe - MOF (visible - light absorption and catalytic activity), the separation efficiency of photo - generated electron - hole pairs is optimized, significantly improving the photothermal conversion performance (the temperature rises to 112.5 °C within 150 s of illumination) and the photo - Fenton catalytic degradation ability (the dye degradation rate > 90% within 90 min). This structure also realizes super - hydrophobicity (water contact angle of 157.4°) and high oil - absorption capacity (103.89 g / g) through increasing surface roughness and synergistic hydrophobic modification with octadecyltrichlorosilane.

[0025] 3. The present invention uses a fluorine - free hydrophobic agent (octadecyltrichlorosilane) and a biocompatible binder (PVA), avoiding the use of perfluorinated compounds and toxic solvents in traditional preparations, reducing environmental risks. By in - situ growing the core - shell structure through a one - step hydrothermal method, the preparation process is simplified, and the material stability is improved (the efficiency still reaches 98.9% after 20 cycles).

[0026] 4. The material of the present invention has a faster heating rate (112.5 °C) under the same light intensity, and the oil absorption capacity is increased by 29.29 times (comparison before and after illumination). At the same time, magnetic-driven manipulation and emulsion separation are realized for the first time (separation efficiency > 99%). Its photo-Fenton catalytic function further expands the application scenarios, and can degrade organic pollutants (such as methylene blue, rhodamine B) while adsorbing crude oil.

[0027] 5. The present invention solves the problems of low adsorption efficiency and cumbersome operation of high-viscosity crude oil through magnetic drive and photothermal viscosity reduction technology, and is applicable to the rapid response of offshore oil spill accidents. The material still maintains stable hydrophobicity in a seawater environment (pH 3 - 11, high salinity), and can achieve low-carbon operation through solar energy drive, combining environmental protection and economy.

[0028] 6. The introduction of metal sulfides can improve the stability of MOFs, making them more stable in complex environments and reducing the risk of structural collapse and performance degradation; at the same time, the porous structure of MOFs can provide a stable dispersion environment for metal sulfides to prevent their aggregation and oxidation. In addition, the two can produce a synergistic effect during the adsorption process. For example, metal sulfides can functionalize MOFs, change their surface properties and pore structure, and improve the adsorption efficiency; MOFs can act as a carrier to make metal sulfides more evenly dispersed, expose more active sites, and enhance the adsorption effect. Brief Description of the Drawings

[0029] Figure 1 It is a schematic flow chart and related properties of the superhydrophobic melamine sponge prepared by the present invention.

[0030] Figure 2 It is the XRD spectra of copper sulfide, CuFe-MOF and copper sulfide@CuFe-MOF in Example 1.

[0031] Figure 3 It is the infrared spectra of copper sulfide, CuFe-MOF and copper sulfide@CuFe-MOF in Example 1.

[0032] Figure 4 It is the water contact angle diagram of the superhydrophobic melamine sponge obtained in Example 1.

[0033] Figure 5 It is the silver mirror phenomenon diagram of the superhydrophobic melamine sponge obtained in Example 1 in water.

[0034] Figure 6 It is the adsorption capacity diagram of the superhydrophobic melamine sponge obtained in Example 1 for different organic solvents or oil substances.

[0035] Figure 7 It is the separation efficiency diagram of the superhydrophobic melamine sponge obtained in Example 1 for different organic solvent / water mixtures.

[0036] Figure 8 Adsorption capacity comparison diagram of the superhydrophobic melamine sponge obtained in Example 1 for chloroform and n-hexane after 20 cycles of adsorption.

[0037] Figure 9 Temperature change diagram over time under sunlight irradiation for the superhydrophobic melamine sponge, superhydrophobic copper sulfide melamine sponge, superhydrophobic CuFe-MOF melamine, and original melamine sponge obtained in Example 1.

[0038] Figure 10 Process diagram of the superhydrophobic CuFe-MOF sponge obtained in Example 1 during the adsorption of high-viscosity castor oil under sunlight irradiation.

[0039] Figure 11 Comparative test of heavy oil adsorption of the superhydrophobic melamine sponge before and after xenon lamp irradiation.

[0040] Figure 12 Transmittance comparison diagram before and after separation of chloroform-in-water, n-hexane-in-water, and toluene-in-water emulsions by the superhydrophobic CuFe-MOF sponge obtained in Example 1.

[0041] Figure 13 Trend of relative concentration change of methylene blue in the octadecyltrichlorosilane / copper sulfide @ CuFe-MOF / MS / hydrogen peroxide system (C t / C0). Detailed implementation manners

[0042] The present invention will be further described below in conjunction with examples, but is not limited thereto.

[0043] Example 1

[0044] (1) Dissolve 1.63 g of copper nitrate dihydrate and 0.53 g of thiourea in 70 mL of ethylene glycol, add 0.78 g of polyvinylpyrrolidone (PVP), stir evenly and then perform ultrasonic treatment for 30 min. Subsequently, transfer the mixture to a 100 mL autoclave and react at 180 °C for 4 h. After the reaction, collect the product by centrifugation (10,000 rpm), wash it three times with deionized water and ethanol respectively, and finally disperse it in 50 mL of a water / ethanol mixture (40 mL of water + 10 mL of ethanol) on a shaker to obtain a copper sulfide-PVP complex.

[0045] (2) Dissolve 1.35 g of iron(III) chloride hexahydrate and 0.426 g of copper(II) chloride dihydrate in 40 mL of ethylene glycol. Add 3.6 g of sodium acetate and 1.0 g of polyethylene glycol. After stirring evenly, transfer the mixture to a 100 mL autoclave and react at 200 °C for 8 h. After the reaction is completed, collect the product by centrifugation (10,000 rpm), wash it three times with deionized water and ethanol respectively, and dry it to obtain the CuFe2O4 precursor.

[0046] (3) Disperse 5 mL of the copper sulfide-PVP composite solution obtained in step (1), 0.3 g of the CuFe2O4 precursor obtained in step (2), and 0.45 g of benzene-1,3,5-tricarboxylic acid (H3BTC) in a 50 mL mixed solution of water and ethanol (40 mL of water + 10 mL of ethanol), ultrasonically treat for 30 min, then transfer the mixture to a Teflon-lined autoclave and react at 150 °C for 12 h. After the reaction is completed, collect the product by centrifugation, wash it three times with deionized water and ethanol respectively, and finally dry it under vacuum at 60 °C to obtain the core-shell structured copper sulfide@CuFe-MOF.

[0047] (4) Dissolve 0.5 g of polyvinyl alcohol (PVA) in 50 mL of deionized water. After stirring evenly, add 0.33 g of the copper sulfide@CuFe-MOF powder obtained in step (3), ultrasonically treat for 30 min, and then immerse it in 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonically treating for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain the copper sulfide@CuFe-MOF / melamine sponge.

[0048] (5) Dissolve 1 mL of octadecyltrichlorosilane (OTS) in 50 mL of n-hexane, ultrasonically treat for 30 min, then immerse the copper sulfide@CuFe-MOF / melamine sponge obtained in step (4), continue ultrasonically treating for 30 min, and finally dry it at 80 °C to obtain the final superhydrophobic octadecyltrichlorosilane / copper sulfide

[0049] @CuFe-MOF / melamine sponge.

[0050] Figure 2XRD characterization results of copper sulfide, CuFe-MOF, and copper sulfide@CuFe-MOF. In the XRD pattern of copper sulfide, the characteristic peaks are located at 29.22°, 31.68°, 47.86°, 59.14°, and 73.62°, which are consistent with the crystal structure of copper sulfide reported in the literature. In the XRD pattern of CuFe-MOF, the diffraction peaks appear at 10.88°, 20.08°, 24.02°, 36.38°, 43.34°, 53.66°, 57.20°, and 61.30°, indicating that the prepared CuFe-MOF has good crystallinity. In the spectrum of copper sulfide@CuFe-MOF, both the characteristic diffraction peaks of copper sulfide and those of CuFe-MOF appear, which not only confirms the coexistence of copper sulfide and CuFe-MOF but also marks the successful synthesis of the core-shell structure copper sulfide@CuFe-MOF.

[0051] Figure 3 IR spectral characterization results of copper sulfide, CuFe-MOF, and copper sulfide@CuFe-MOF. In the infrared spectrum of copper sulfide, the absorption peak at 617 cm -1 is the characteristic absorption peak of copper sulfide, which can be attributed to the stretching vibration of Cu-S. In the infrared spectrum of CuFe-MOF, the broad absorption band in the range of 3600 - 3000 cm -1 corresponds to the O-H vibration of coordinated water molecules; the absorption peaks at 1623 cm -1 , 1572 cm -1 , 1450 cm -1 and 1384 cm -1 can be attributed to the vibration of carboxylate groups in the organic ligand H3BTC; the absorption peaks at 763 cm -1 and 713 cm -1 are related to the characteristic vibration of the meta-trisubstituted structure of the benzene ring in H3BTC. In the infrared spectrum of copper sulfide@CuFe-MOF, the characteristic absorption peaks of both copper sulfide and CuFe-MOF appear simultaneously, further proving the successful synthesis of the core-shell structure of copper sulfide@CuFe-MOF.

[0052] Figure 4 Hydrophobic angle diagram of the modified sponge. The water contact angle of the modified sponge can reach 157.4°, and there is an obvious "silver mirror phenomenon" underwater ( Figure 5 ), proving that the superhydrophobic melamine sponge prepared by the present invention has excellent superhydrophobicity.

[0053] The modified sponge was immersed in 20 mL of oily substances or organic solvents (chloroform, n-hexane, octane, dichloromethane, benzene, toluene, petroleum ether, heavy oil) for saturated adsorption, and its mass before and after adsorption was measured. The adsorption capacity can be calculated according to the following equation:

[0054] Q = (m1 - m0) / m0

[0055] Where m0 and m1 are the masses of the modified sponge before and after adsorption respectively, and Q is the adsorption capacity.

[0056] The test results are as Figure 6 shown. The modified sponge exhibits excellent adsorption capacity, and its adsorption capacity can reach 39.11 (for n - hexane) - 103.89 (for chloroform) times its own weight.

[0057] Deionized water and organic solvents (chloroform, n - hexane, octane, dichloromethane, benzene, toluene, petroleum ether) were mixed at a volume ratio of 1:1, and the modified sponge was added to adsorb the organic solvents. The masses of the deionized water before and after separation were measured, and the oil - water separation efficiency can be calculated by the following equation:

[0058] η = m b / m a

[0059] Where m a and m b are the masses of the deionized water before and after separation respectively, and η is the oil - water separation efficiency.

[0060] The test results are as Figure 7 shown. The separation efficiencies of the sponge for chloroform / water, n - hexane / water, octane / water, dichloromethane / water, benzene / water, toluene / water, petroleum ether / water are 99.14%, 99.95%, 99.92%, 99.98%, 99.98%, 99.94%, 99.95% respectively, proving that the super - hydrophobic melamine sponge prepared by the present invention has excellent oil - water separation performance.

[0061] The recyclability of the modified sponge was studied through adsorption - desorption experiments. After the sponge reached saturation adsorption each time, it was completely compressed and dried for the next cycle. After 20 cycles, the adsorption capacities of the modified sponge for n - hexane and chloroform were still up to 36.52 g / g and 95.64 g / g ( Figure 8 ), so the super - hydrophobic melamine sponge prepared by the present invention has excellent durability.

[0062] The temperature changes of the original sponge and the modified sponge under sunlight irradiation were explored through experiments, and further the oil - water separation effect of the modified sponge on high - viscosity oil - water under sunlight irradiation was studied. As Figure 9 shown, after 150 s of sunlight irradiation, the surface temperature of the original sponge rose from 30.0 °C to 81.9 °C, while the surface temperature of the modified sponge rose from 30.0 °C to 112.5 °C. The temperature of the modified sponge was significantly higher than that of the original sponge. As Figure 10As shown in the figure, under sunlight irradiation, the modified sponge rapidly heats up itself and can quickly adsorb highly viscous methyl silicone oil on the water surface, achieving efficient oil-water separation. Therefore, the superhydrophobic melamine sponge prepared by the present invention has excellent photothermal performance and thermal conductivity.

[0063] The emulsion purification ability of the modified sponge for chloroform-in-water, hexane-in-water, and toluene-in-water emulsions was explored through experiments. The specific experimental steps are as follows:

[0064] Mix 48 mL of water and 8 mL of oil (chloroform, hexane, toluene), add 0.02 g of Span 80 as a surfactant, and stir at high speed for 6 h to prepare three oil-in-water emulsions. Immerse the modified sponge into the three emulsions through external force and stir to achieve emulsion purification. Use an ultraviolet spectrophotometer to measure the light transmittance of each emulsion before and after separation. The results are as Figure 11 shown. After treatment with the modified sponge, the light transmittance of each emulsion has been greatly improved and all reached more than 90%. Therefore, the modified sponge has high emulsion purification ability.

[0065] The adsorption and degradation abilities of the original sponge and the modified sponge (both with a volume of 1×1×1 cm 3 ) for common organic dyes were compared through experiments. In the experiments, methylene blue, methyl orange, rhodamine B, and crystal violet were used as target dyes respectively, a 0.1 g / L dye solution was prepared, and adsorption and degradation experiments were carried out under sunlight.

[0066] As Figure 13 shown, the original sponge can only adsorb a small amount of dye and has almost no degradation effect under light conditions. In contrast, after 90 min of light irradiation, the degradation rates of methylene blue, methyl orange, rhodamine B, and crystal violet by the modified sponge reached 95%, 92%, 90%, and 88% respectively. In addition, the adsorption amount of the modified sponge for dyes is significantly higher than that of the original sponge, and it still maintains a high adsorption and degradation efficiency in multiple cycle experiments.

[0067] Therefore, the modified sponge not only has high dye adsorption ability, but also can achieve rapid degradation of dyes through the photo-Fenton reaction, showing good catalytic performance and environmental adaptability, providing an efficient and environmentally friendly solution for the treatment of organic pollutants.

[0068] Experimental Example 2

[0069] (1) The preparation steps of copper sulfide-PVP, CuFe2O4 precursor, and core-shell structured copper sulfide@CuFe-MOF are the same as those in Example 1.

[0070] (2) Dissolve 0.3 g of polyvinyl alcohol (PVA) in 50 mL of deionized water. After stirring evenly, add 0.2 g of the copper sulfide@CuFe-MOF powder obtained in step (1), and ultrasonically treat for 30 min. Then immerse it in 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonically treating for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide@CuFe-MOF / melamine sponge.

[0071] (3) Obtain the final superhydrophobic octadecyltrichlorosilane / copper sulfide@CuFe-MOF / melamine sponge in the same way as in Example 1.

[0072] The water contact angle of the modified sponge is 152°, the adsorption capacities for n-hexane and chloroform are 35.9 g / g and 99.5 g / g respectively, and the separation efficiency of the n-hexane / water mixture is 98.5%.

[0073] Experimental Example 3

[0074] (1) The preparation steps of copper sulfide-PVP, CuFe₂O₄ precursor and core-shell structured copper sulfide@CuFe-MOF are the same as in Example 1.

[0075] (2) Dissolve 0.35 g of polyvinyl alcohol (PVA) in 50 mL of deionized water. After stirring evenly, add 0.23 g of the copper sulfide@CuFe-MOF powder obtained in step (1), and ultrasonically treat for 30 min. Then immerse it in 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonically treating for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide@CuFe-MOF / melamine sponge.

[0076] (3) Obtain the final superhydrophobic octadecyltrichlorosilane / copper sulfide@CuFe-MOF / melamine sponge in the same way as in Example 1.

[0077] The water contact angle of the modified sponge is 151°, the adsorption capacities for n-hexane and chloroform are 35.2 g / g and 98.7 g / g respectively, and the separation efficiency of the n-hexane / water mixture is 98.2%.

[0078] Experimental Example 4

[0079] (1) The preparation steps of copper sulfide-PVP, CuFe₂O₄ precursor and core-shell structured copper sulfide@CuFe-MOF are the same as in Example 1.

[0080] (2) Dissolve 0.6 g of polyvinyl alcohol (PVA) in 50 mL of deionized water. After stirring evenly, add 0.4 g of the copper sulfide@CuFe-MOF powder obtained in step (1), and ultrasonically treat for 30 min. Then immerse it in 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonic treatment for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide@CuFe-MOF / melamine sponge.

[0081] (3) Obtain the final superhydrophobic octadecyltrichlorosilane / copper sulfide@CuFe-MOF / melamine sponge in the same way as in Example 1.

[0082] The water contact angle of the modified sponge is 152°, the adsorption capacities for n-hexane and chloroform are 32.7 g / g and 95.4 g / g respectively, and the separation efficiency of the n-hexane / water mixture is 96.5%.

[0083] Experimental Example 5

[0084] (1) The preparation steps of copper sulfide-PVP, CuFe2O4 precursor and core-shell structured copper sulfide@CuFe-MOF are the same as in Example 1.

[0085] (2) Dissolve 0.66 g of polyvinyl alcohol (PVA) in 50 mL of deionized water. After stirring evenly, add 0.33 g of the copper sulfide@CuFe-MOF powder obtained in step (1), and ultrasonically treat for 30 min. Then immerse it in 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonic treatment for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide@CuFe-MOF / melamine sponge.

[0086] (3) Obtain the final superhydrophobic octadecyltrichlorosilane / copper sulfide@CuFe-MOF / melamine sponge in the same way as in Example 1.

[0087] The water contact angle of the modified sponge is 151°, the adsorption capacities for n-hexane and chloroform are 32.4 g / g and 95.2 g / g respectively, the separation efficiency of the n-hexane / water mixture is 97.5%, and the surface temperature rises to 93.1 °C after 150 s of xenon lamp irradiation.

[0088] Experimental Example 6

[0089] (1) The preparation steps of copper sulfide-PVP, CuFe2O4 precursor and core-shell structured copper sulfide@CuFe-MOF are the same as in Example 1.

[0090] (2) Dissolve 0.17 g of polyvinyl alcohol (PVA) in 50 mL of deionized water. After stirring evenly, add 0.33 g of the copper sulfide@CuFe-MOF powder obtained in step (1), and ultrasonically treat for 30 min. Then immerse it in 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonically treating for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide@CuFe-MOF / melamine sponge.

[0091] (3) Obtain the final superhydrophobic octadecyltrichlorosilane / copper sulfide@CuFe-MOF / melamine sponge in the same way as in Example 1.

[0092] The water contact angle of the modified sponge is 145°, the adsorption capacities for n-hexane and chloroform are 35.8 g / g and 94.2 g / g respectively, and the separation efficiency of the n-hexane / water mixture is 96.4%.

[0093] Example 7

[0094] (1) Obtain the copper sulfide-PVP composite in the same way as in Example 1.

[0095] (2) Obtain the CuFe2O4 precursor in the same way as in Example 1.

[0096] (3) Disperse 5 mL of the copper sulfide-PVP composite solution obtained in step (1), 0.15 g of the CuFe2O4 precursor obtained in step (2), and 0.74 g of trimesic acid (H3BTC) in a 50 mL mixed solution of water and ethanol, ultrasonically treat for 30 min, and then transfer the mixture to a polytetrafluoroethylene-lined autoclave and react at 150 °C for 12 h. After the reaction is completed, collect the product by centrifugation, wash it with deionized water and ethanol, and finally dry it under vacuum at 60 °C to obtain core-shell structured copper sulfide@CuFe-MOF.

[0097] (4) Dissolve 0.5 g of polyvinyl alcohol (PVA) in 50 mL of deionized water. After stirring evenly, add 0.33 g of the copper sulfide@CuFe-MOF powder obtained in step (3), and ultrasonically treat for 30 min. Then immerse it in 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonically treating for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide@CuFe-MOF / melamine sponge.

[0098] (5) Dissolve 1 mL of octadecyltrichlorosilane (OTS) in 50 mL of n - hexane, ultrasonically treat for 30 min, then immerse the copper sulfide@CuFe - MOF / melamine sponge obtained in step (4), continue ultrasonically treating for 30 min, and finally dry at 80 °C to obtain the final super - hydrophobic octadecyltrichlorosilane / copper sulfide

[0099] @CuFe - MOF / melamine sponge.

[0100] The water contact angle of the modified sponge is 149°, the adsorption capacities for n - hexane and chloroform are 38.7 g / g and 95.6 g / g respectively, and the separation efficiency of the n - hexane / water mixture is 96.7%.

[0101] Example 8

[0102] (1) Obtain the copper sulfide - PVP composite as in Example 1.

[0103] (2) Obtain the CuFe₂O₄ precursor as in Example 1.

[0104] (3) Disperse 5 mL of the copper sulfide - PVP composite solution obtained in step (1), 0.62 g of the CuFe₂O₄ precursor obtained in step (2), and 0.65 g of trimesic acid (H₃BTC) in a 50 mL water - ethanol mixed solution, ultrasonically treat for 30 min, then transfer the mixture to a polytetrafluoroethylene - lined autoclave and react at 150 °C for 12 h. After the reaction, collect the product by centrifugation, wash it with deionized water and ethanol, and finally dry it under vacuum at 60 °C to obtain the core - shell structured copper sulfide@CuFe - MOF.

[0105] (4) Dissolve 0.5 g of polyvinyl alcohol (PVA) in 50 mL of deionized water, stir evenly, add 0.33 g of the copper sulfide@CuFe - MOF powder obtained in step (3), ultrasonically treat for 30 min, then immerse 6 original melamine sponges (volume: 1×1×1 cm 3 ), continue ultrasonically treating for 2 h. After the treatment, squeeze the sponges dry and dry them at 120 °C for 3 h to obtain the copper sulfide@CuFe - MOF / melamine sponge.

[0106] (5) Dissolve 1 mL of octadecyltrichlorosilane (OTS) in 50 mL of n - hexane, ultrasonically treat for 30 min, then immerse the copper sulfide@CuFe - MOF / melamine sponge obtained in step (4), continue ultrasonically treating for 30 min, and finally dry at 80 °C to obtain the final super - hydrophobic octadecyltrichlorosilane / copper sulfide

[0107] @CuFe - MOF / melamine sponge.

[0108] The water contact angle of the modified sponge is 156°, the adsorption capacities for n-hexane and chloroform are 37.3 g / g and 98.4 g / g respectively, and the separation efficiency of the n-hexane / water mixture is 97.4%.

[0109] Example 9

[0110] (1) Dissolve 1.63 g of copper nitrate dihydrate and 0.53 g of thiourea in 70 mL of ethylene glycol, add 1.56 g of polyvinylpyrrolidone (PVP), stir evenly and then perform ultrasonic treatment for 30 min. Subsequently, transfer the mixture to a 100 mL autoclave and react at 180 °C for 4 h. After the reaction, collect the product by centrifugation (10,000 rpm), wash it with deionized water and ethanol, and finally disperse it in a 50 mL water / ethanol mixture (40 mL of water + 10 mL of ethanol) on a shaker to obtain a copper sulfide-PVP composite.

[0111] (2)-(5) are the same as in Example 1.

[0112] The water contact angle of the modified sponge is 156°, the adsorption capacities for n-hexane and chloroform are 29.1 g / g and 86.4 g / g respectively, and the separation efficiency of the n-hexane / water mixture is 96.7%.

[0113] Example 10

[0114] (1) Dissolve 1.63 g of copper nitrate dihydrate and 0.53 g of thiourea in 70 mL of ethylene glycol, add 0.39 g of polyvinylpyrrolidone (PVP), stir evenly and then perform ultrasonic treatment for 30 min. Subsequently, transfer the mixture to a 100 mL autoclave and react at 180 °C for 4 h. After the reaction, collect the product by centrifugation (10,000 rpm), wash it with deionized water and ethanol, and finally disperse it in a 50 mL water / ethanol mixture (40 mL of water + 10 mL of ethanol) on a shaker to obtain a copper sulfide-PVP composite.

[0115] (2)-(5) are the same as in Example 1.

[0116] The water contact angle of the modified sponge is 147°, the adsorption capacities for n-hexane and chloroform are 32.6.1 g / g and 91.2 g / g respectively, and the separation efficiency of the n-hexane / water mixture is 97.2%.

[0117] Experimental Example 11

[0118] (1) The preparation steps of copper sulfide-PVP, CuFe2O4 precursor and core-shell structured copper sulfide@CuFe-MOF are the same as in Example 1.

[0119] (2) Dissolve 0.5 g of polyvinyl alcohol (PVA) in 50 mL of deionized water. After stirring evenly, add 0.33 g of the copper sulfide@CuFe-MOF powder obtained in step (1), and perform ultrasonic treatment for 30 min. Then immerse it into 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonic treatment for 1.5 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide@CuFe-MOF / melamine sponge.

[0120] (3) Obtain the final superhydrophobic octadecyltrichlorosilane / copper sulfide@CuFe-MOF / melamine sponge in the same way as in Example 1.

[0121] The water contact angle of the modified sponge is 155°, the adsorption capacities for n-hexane and chloroform are 37.8 g / g and 101.5 g / g respectively, and the separation efficiency of the n-hexane / water mixture is 98.9%.

[0122] Experimental Example 12

[0123] (1) The preparation steps of copper sulfide-PVP, CuFe2O4 precursor and core-shell structured copper sulfide@CuFe-MOF are the same as those in Example 1.

[0124] (2) Dissolve 0.5 g of polyvinyl alcohol (PVA) in 50 mL of deionized water. After stirring evenly, add 0.33 g of the copper sulfide@CuFe-MOF powder obtained in step (1), and perform ultrasonic treatment for 30 min. Then immerse it into 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonic treatment for 2.5 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide@CuFe-MOF / melamine sponge.

[0125] (3) Obtain the final superhydrophobic octadecyltrichlorosilane / copper sulfide@CuFe-MOF / melamine sponge in the same way as in Example 1.

[0126] The water contact angle of the modified sponge is 155°, the adsorption capacities for n-hexane and chloroform are 33.8 g / g and 100.5 g / g respectively, and the separation efficiency of the n-hexane / water mixture is 98.9%.

[0127] Experimental Example 13

[0128] (1) The preparation steps of copper sulfide-PVP, CuFe2O4 precursor and core-shell structured copper sulfide@CuFe-MOF are the same as those in Example 1.

[0129] (2) The preparation steps of obtaining copper sulfide@CuFe-MOF / melamine sponge are the same as those in Example 1.

[0130] (3) Dissolve 0.8 mL of octadecyltrichlorosilane (OTS) in 50 mL of n - hexane, ultrasonically treat for 30 min, then immerse the copper sulfide@CuFe - MOF / melamine sponge obtained in step (2), continue ultrasonically treating for 30 min, and finally dry at 80 °C to obtain the final super - hydrophobic octadecyltrichlorosilane / copper sulfide@CuFe - MOF / melamine sponge.

[0131] The water contact angle of the modified sponge is 152°, the adsorption capacities for n - hexane and chloroform are 39.2 g / g and 103.9 g / g respectively, and the separation efficiency of the n - hexane / water mixture is 99.2%.

[0132] Experimental Example 14

[0133] (1) The preparation steps of copper sulfide - PVP, CuFe₂O₄ precursor and core - shell structured copper sulfide@CuFe - MOF are the same as those in Example 1.

[0134] (2) The preparation steps of obtaining copper sulfide@CuFe - MOF / melamine sponge are the same as those in Example 1.

[0135] (3) Dissolve 1.2 mL of octadecyltrichlorosilane (OTS) in 50 mL of n - hexane, ultrasonically treat for 30 min, then immerse the copper sulfide@CuFe - MOF / melamine sponge obtained in step (2), continue ultrasonically treating for 30 min, and finally dry at 80 °C to obtain the final super - hydrophobic octadecyltrichlorosilane / copper sulfide@CuFe - MOF / melamine sponge.

[0136] The water contact angle of the modified sponge is 153°, the adsorption capacities for n - hexane and chloroform are 38.9 g / g and 102.7 g / g respectively, and the separation efficiency of the n - hexane / water mixture is 99.1%.

[0137] Comparative Example 1

[0138] (1) Dissolve 1.63 g of copper nitrate dihydrate and 0.53 g of thiourea in 70 mL of ethylene glycol, stir evenly and ultrasonically treat for 30 min. Subsequently, transfer the mixture to a 100 mL autoclave and react at 180 °C for 4 h. After the reaction, collect the product by centrifugation (10,000 rpm), and wash with deionized water and ethanol, and dry at 80 °C to obtain copper sulfide powder.

[0139] (2) Dissolve 0.5 g of polyvinyl alcohol (PVA) in 50 mL of deionized water, stir evenly and add 0.33 g of the copper sulfide powder obtained in step (1), ultrasonically treat for 30 min, and then immerse 6 original melamine sponges (volume: 1×1×1 cm 3), continue ultrasonic treatment for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide / melamine sponge.

[0140] (3) Dissolve 1 mL of octadecyltrichlorosilane (OTS) in 50 mL of n-hexane, perform ultrasonic treatment for 30 min, then immerse the copper sulfide / melamine sponge obtained in step (2), continue ultrasonic treatment for 30 min, and finally dry at 80 °C to obtain the final superhydrophobic octadecyltrichlorosilane / copper sulfide / melamine sponge.

[0141] The water contact angle of the modified sponge is 155°, the adsorption capacities for n-hexane and chloroform are 32.1 g / g and 94.8 g / g respectively, the separation efficiency of the n-hexane / water mixture is 96.8%, and the surface temperature rises to 99.4 °C after 150 s of xenon lamp irradiation.

[0142] Comparative Example 2

[0143] (1) The steps for preparing the CuFe2O4 precursor are the same as in Example 1.

[0144] (2) Disperse 0.3 g of the CuFe2O4 precursor obtained in step (1) and 0.45 g of trimesic acid (H3BTC) in a 50 mL mixed solution of water and ethanol, perform ultrasonic treatment for 30 min, then transfer the mixture to a high-pressure autoclave lined with polytetrafluoroethylene and react at 150 °C for 12 h. After the reaction is completed, collect the product by centrifugation, wash it with deionized water and ethanol, and finally dry it under vacuum at 60 °C to obtain CuFe-MOF powder.

[0145] (3) Dissolve 0.5 g of polyvinyl alcohol (PVA) in 50 mL of deionized water, stir evenly, add 0.33 g of the CuFe-MOF nanoparticles obtained in step (3), perform ultrasonic treatment for 30 min, then immerse 6 original melamine sponges (volume: 1×1×1 cm 3 ), continue ultrasonic treatment for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain CuFe-MOF / melamine sponge.

[0146] (4) Dissolve 1 mL of octadecyltrichlorosilane (OTS) in 50 mL of n-hexane, perform ultrasonic treatment for 30 min, then immerse the CuFe-MOF / melamine sponge obtained in step (2), continue ultrasonic treatment for 30 min, and finally dry at 80 °C to obtain the final superhydrophobic octadecyltrichlorosilane / copper sulfide / CuFe-MOF / melamine sponge.

[0147] The water contact angle of the modified sponge is 155°, the adsorption capacities for n - hexane and chloroform are 38.1 g / g and 96.8 g / g respectively, the separation efficiency of the n - hexane / water mixture is 97.8%, and the surface temperature rises to 89.4 °C after 150 s of xenon lamp irradiation.

[0148] Comparative Example 3

[0149] (1) Dissolve 0.45 g of stannous chloride dihydrate and 0.53 g of thiourea in 70 mL of ethylene glycol, add 0.78 g of polyvinylpyrrolidone (PVP), stir evenly and then perform ultrasonic treatment for 30 min. Subsequently, transfer the mixture to a 100 mL autoclave and react at 190 °C for 4 h. After the reaction is completed, collect the product by centrifugation (10,000 rpm) and wash it with deionized water and ethanol to obtain the tin sulfide - PVP composite.

[0150] (2) Obtain the CuFe₂O₄ precursor in the same way as in Example 1.

[0151] (3) Disperse 5 mL of the tin sulfide - PVP composite solution obtained in step (1), 0.3 g of the CuFe₂O₄ precursor obtained in step (2), and 0.45 g of benzene - 1,3,5 - tricarboxylic acid (H₃BTC) in a 50 mL mixed solution of water and ethanol, perform ultrasonic treatment for 30 min, and then transfer the mixture to a Teflon - lined autoclave and react at 150 °C for 12 h. After the reaction is completed, collect the product by centrifugation and wash it with deionized water and ethanol, and finally dry it in vacuum at 60 °C to obtain the core - shell structured tin sulfide@CuFe - MOF.

[0152] (4) Dissolve 0.5 g of polyvinyl alcohol (PVA) in 50 mL of deionized water, stir evenly and then add 0.33 g of the tin sulfide@CuFe - MOF powder obtained in step (3), perform ultrasonic treatment for 30 min, and then immerse it into 6 original melamine sponges (volume: 1×1×1 cm 3 ), and continue ultrasonic treatment for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain the tin sulfide@CuFe - MOF / melamine sponge.

[0153] (5) Dissolve 1 mL of octadecyltrichlorosilane (OTS) in 50 mL of n - hexane, perform ultrasonic treatment for 30 min, and then immerse it into the tin sulfide@CuFe - MOF / melamine sponge obtained in step (4), continue ultrasonic treatment for 30 min, and finally dry it at 80 °C to obtain the final super - hydrophobic octadecyltrichlorosilane / tin sulfide

[0154] @CuFe - MOF / melamine sponge.

[0155] The water contact angle of the modified sponge is 153°, the adsorption capacities for n - hexane and chloroform are 35.1 g / g and 96.8 g / g respectively, the separation efficiency of the n - hexane / water mixture is 95.9%, and the surface temperature rises to 83.2 °C after 150 s of xenon lamp irradiation.

[0156] Comparative Example 4

[0157] (1) The preparation of the copper sulfide - PVP composite is the same as in Example 1.

[0158] (2) Add 20 mL of DMF, 20 mL of ethanol, and 20 mL of deionized water into a beaker in sequence and carry out magnetic stirring. Add 5 mL of the copper sulfide - PVP composite obtained in step (1), 0.88 g of Ni(NO3)2·6H2O, 0.24 g of terephthalic acid, and 0.78 g of PVP into the beaker in sequence, and then stir magnetically for 1 h. Then, transfer the mixture into a 100 - mL autoclave, place it in a blast dryer at 150 °C, and react for 10 h. After the reaction is completed, take out the autoclave, cool it to room temperature, centrifuge it in a centrifuge at 10000 r / min, and wash it once with DMF, deionized water, and ethanol in sequence. Finally, disperse the obtained solid in 50 mL of a water / ethanol mixture (40 mL of water + 10 mL of ethanol) with a shaker to obtain copper sulfide@Ni - MOF.

[0159] (3) Dissolve 0.5 g of polyvinyl alcohol (PVA) in 50 mL of deionized water, stir evenly, add 0.33 g of the copper sulfide@Ni - MOF powder obtained in step (2), perform ultrasonic treatment for 30 min, and then immerse 6 original melamine sponges (volume: 1×1×1 cm 3 ) and continue ultrasonic treatment for 2 h. After the treatment is completed, squeeze the sponge dry and dry it at 120 °C for 3 h to obtain copper sulfide@Ni - MOF / melamine sponge.

[0160] (4) Dissolve 1 mL of octadecyltrichlorosilane (OTS) in 50 mL of n - hexane, perform ultrasonic treatment for 30 min, then immerse the copper sulfide@Ni - MOF / melamine sponge obtained in step (4), continue ultrasonic treatment for 30 min, and finally dry it at 80 °C to obtain the final super - hydrophobic octadecyltrichlorosilane / copper sulfide@Ni - MOF / melamine sponge.

[0161] The water contact angle of the modified sponge is 156°, the adsorption capacities for n - hexane and chloroform are 37.4 g / g and 92.9 g / g respectively, the separation efficiency of the n - hexane / water mixture is 95.9%, and the surface temperature rises to 87.2 °C after 150 s of xenon lamp irradiation.

[0162] The above-described embodiments are merely preferred examples given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art of this technology on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A multifunctional superhydrophobic melamine sponge based on a core-shell metal-organic framework structure, characterized in that: The multifunctional superhydrophobic melamine sponge is prepared by immersing a melamine sponge into a mixed solution of core-shell structured copper sulfide@CuFe-MOF and polyvinyl alcohol, and then treating it with octadecyltrichlorosilane.

2. The multifunctional superhydrophobic melamine sponge based on the core-shell metal-organic framework structure according to claim 1, characterized in that The preparation method of the core-shell structured copper sulfide@CuFe-MOF is as follows: Disperse copper sulfide-PVP complex, CuFe2O4 precursor and trimesic acid in a mixed solution of water and ethanol. After ultrasonic treatment, transfer the mixture to an autoclave and react at 150 °C for 12 h. Then collect the product by centrifugation, wash it with deionized water and ethanol, and finally dry it under vacuum to obtain the core-shell structured copper sulfide@CuFe-MOF.

3. The multifunctional superhydrophobic melamine sponge based on the core-shell metal-organic framework structure according to claim 2, wherein, The volume-mass ratio of the copper sulfide-PVP dispersion: CuFe2O4 precursor: trimesic acid is 5 mL: 0.15 - 0.84 g: 0.45 - 0.74 g.

4. The multifunctional superhydrophobic melamine sponge based on the core-shell metal-organic framework structure according to claim 2, wherein, The preparation method of the copper sulfide-PVP complex is as follows: Dissolve copper nitrate hydrate and thiourea in ethylene glycol, then add polyvinylpyrrolidone, stir evenly and perform ultrasonic treatment. Transfer the mixture to a high-pressure reaction kettle and react at 180 °C for 4 h. Then collect the product by centrifugation, wash it with deionized water and ethanol, and disperse the obtained particles in a water / ethanol solution to obtain a copper sulfide-PVP complex dispersion.

5. The multifunctional superhydrophobic melamine sponge based on the core-shell metal-organic framework structure according to claim 2, wherein The preparation method of the CuFe2O4 precursor is as follows: Dissolve ferric chloride hexahydrate and copper chloride dihydrate in ethylene glycol, then add sodium acetate and polyethylene glycol, stir evenly and transfer the mixture to a high-pressure reaction kettle. React at 200 °C for 8 h, then collect the product by centrifugation, wash it with deionized water and ethanol, and dry it to obtain the CuFe2O4 precursor.

6. A preparation method of the multifunctional superhydrophobic melamine sponge based on a core-shell metal-organic framework structure according to claim 1, characterized in that, The steps of the preparation method are as follows: (1) Add copper sulfide@CuFe-MOF and polyvinyl alcohol to deionized water according to the mass ratio, stir evenly and perform ultrasonic treatment for 30 min. Then immerse a melamine sponge and continue ultrasonic treatment for 0.5 - 2.5 h, and then dry it to obtain a copper sulfide@CuFe-MOF melamine sponge; (2) Immerse the copper sulfide@CuFe-MOF melamine sponge obtained in step (1) into a n-hexane solution of octadecyltrichlorosilane, perform ultrasonic treatment for 30 min and then dry it to obtain a superhydrophobic octadecyltrichlorosilane / copper sulfide@CuFe-MOF / melamine sponge.

7. The preparation method of the multifunctional superhydrophobic melamine sponge based on the core-shell metal-organic framework structure according to claim 6, characterized in that, In step (1), the mass ratio of copper sulfide@CuFe-MOF to polyvinyl alcohol is 1:0.5 - 1:2; the concentration of polyvinyl alcohol in deionized water is 0.17 - 0.66 g / 50 mL; the drying temperature is 120 °C and the drying time is 3 h.

8. The preparation method of the multifunctional superhydrophobic melamine sponge based on the core-shell metal-organic framework structure according to claim 6, characterized in that, In step (2), the concentration of octadecyltrichlorosilane in the n-hexane solution is 0.4 - 1.2 mL / 50 mL, and the drying temperature is 80 °C.

9. Use of the multifunctional superhydrophobic melamine sponge based on a core-shell metal-organic framework structure according to claim 1, characterized in that, The multifunctional superhydrophobic melamine sponge is used for high-viscosity oil-water separation, emulsion purification and catalytic degradation of organic dyes.

10. Use of the multifunctional superhydrophobic melamine sponge based on a core-shell metal-organic framework structure according to claim 9, characterized in that, The high-viscosity oil-water separation includes the adsorption of methyl silicone oil, castor oil or pump oil; the catalytic degradation of organic dyes includes the degradation of methylene blue, methyl orange, rhodamine B or crystal violet.

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