Super-hydrophobic melamine sponge with roughness constructed based on multiple particles as well as preparation method and application of super-hydrophobic melamine sponge

Abstract

The invention belongs to the technical field of oil-water separation materials, and particularly relates to a super-hydrophobic melamine sponge with roughness constructed based on multiple particles and a preparation method and application thereof. The preparation method comprises the following steps: loading silicon dioxide nanoparticles with different particle sizes on melamine sponge through a simple dip-coating method by utilizing the bonding capacity of phenolic resin to construct a rough structure surface; and under the synergistic effect of the nanoparticles with different particle sizes, the surface roughness of the sponge is further improved. And then stearic acid is introduced to carry out hydrophobization treatment on the rough surface, so that the sponge has the super-hydrophobic / super-oleophylic characteristic. The prepared phenolic resin, silicon dioxide, stearic acid and melamine sponge shows excellent oil-water separation performance on organic solvents and oil compounds, and has stability in a high-temperature or strong acid / strong alkali environment.

Description

Technical Field

[0001] This invention belongs to the field of oil-water separation materials technology, specifically relating to a superhydrophobic melamine sponge based on roughness constructed from multiple particles, its preparation method, and its application. Background Technology

[0002] In today's society, oil-water separation is an important environmental and industrial technological requirement. Traditional oil-water separation methods have many limitations and fail to meet the requirements of high efficiency, stability, and economy. Melamine sponge, with its unique three-dimensional porous structure and high specific surface area, has become a highly promising oil-water separation material. However, its hydrophilicity and limited adsorption capacity restrict its effectiveness in practical applications. Therefore, developing a high-efficiency, stable, and economical oil-water separation material is of significant practical importance.

[0003] Existing methods for preparing superhydrophobic melamine sponges (MS) mainly include: immersing melamine sponges in graphene oxide (GO) solution, coating with polydimethylsiloxane (PDMS), modifying with silane coupling agents, modifying with polydopamine, and loading cuprous sulfide nanoparticles and PDMS to obtain superhydrophobic-superoleophilic properties for oil-water separation, achieving separation efficiencies of over 99%. In addition, biomimetic melamine sponges with mechanical / chemical durability and low fire risk have been developed through synergistic modification of MOFs and PDMS.

[0004] However, superhydrophobic melamine sponges still suffer from drawbacks such as poor adhesion between the superhydrophobic material and the substrate, leading to easy detachment; poor durability, with the surface easily contaminated by oil, resulting in degradation of the superhydrophobic properties; and some synthesis methods involve secondary pollution of raw materials, high costs, and complex processes, making large-scale production difficult. Furthermore, they exhibit low efficiency in separating high-viscosity oils and insufficient stability in harsh environments such as high-radiation environments. Therefore, the development of a highly efficient, stable, and economical oil-water separation material is urgently needed. Summary of the Invention

[0005] This invention aims to provide a superhydrophobic melamine sponge based on roughness constructed from multiple particles, its preparation method, and its application. This sponge achieves superhydrophobic / superoleophilic properties by constructing a rough structure on the surface of the melamine sponge and performing hydrophobic modification, exhibiting excellent oil-water separation performance and stability.

[0006] The main steps of the method for constructing a roughness-based superhydrophobic melamine sponge using multiple particles are as follows: (1) At 51°C, 65 mL of ethanol and 2 mL of ammonia (25 wt%) were mixed evenly. Then, 6.5 mL of LTEOS was added dropwise, stirred for 6 h, centrifuged, washed three times with ethanol, and finally dried at 60°C to obtain 20 nm silica particles.

[0007] 4 mL of TEOS was added to 40 mL of ethanol under stirring at room temperature, followed by 1.6 mL of ammonia (25 wt%), and stirring was maintained for 20 min. The mixture was left to stand unstirred for 2 days to generate uniform 40-80 nm silica nanoparticles. After centrifugation, the nanoparticles were washed three times with ethanol and finally dried at 60 °C to obtain dry 40-80 nm silica nanoparticles.

[0008] (2) Preparation of phenolic resin solution: Add 0.4-0.6 g of phenolic resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder solution. Next, prepare a silica / ethanol solution: Add 40-80 nm silica particles and 20 nm silica particles to 50 mL of ethanol at a mass ratio to prepare a silica-ethanol solution. Then, immerse the pretreated melamine sponge in the binder solution and soak it under ultrasonic conditions for 1 h to obtain phenolic resin@melamine sponge. Then, put the phenolic resin@melamine sponge into 10 mL of silica / ethanol solution and soak it for 6-18 h. After soaking, take it out and dry it in an oven at 60 ℃ to obtain phenolic resin@silica@melamine sponge.

[0009] The mass ratio of 40-80 nm silica particles to 20 nm silica particles is 1:0.5-2; the concentration of the silica ethanol solution is 0.1 g / ml.

[0010] (3) Prepare a stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge for a certain period of time, and then dry it in an oven at 60 ℃ to obtain a superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0011] The stearic acid solution concentration was 7.5-12.5 mM, and the polyurethane sponge soaking time was 2-6 h.

[0012] The superhydrophobic melamine sponge prepared by the above method based on the roughness of multiple particles is applied to oil-water separation, especially for separating organic solvents and oil compounds.

[0013] The beneficial effects of this invention are: 1. This invention is the first to integrate a micro-nano rough structure constructed by dual-size silica nanoparticles with low surface energy modification of stearic acid into a sponge skeleton through a phenolic resin high adhesion substrate, thereby achieving an integrated design of superhydrophobicity (contact angle 153.5°), high oil absorption (23.54-56.84 g / g) and corrosion resistance / mechanical stability, breaking through the bottleneck of single function of traditional hydrophobic materials.

[0014] 2. This invention innovatively proposes to construct a graded rough surface by compounding two types of silica nanoparticles with sizes of 20nm and 40-80nm in a mass ratio of 0.5-2:1, and then modifying it with 10mM stearic acid for low surface energy. The resulting superhydrophobic material has a separation efficiency of over 98.36% for immiscible oil-water systems such as hexane / water and chloroform / water.

[0015] 3. This invention uses stearic acid for surface modification to reduce environmental risks; phenolic resin strongly anchors silica nanoparticles to ensure structural integrity; it maintains high efficiency in hydrophobicity and separation performance after 13 cycles of use, and is resistant to repeated mechanical pressure and chemical corrosion (pH 3–11, high salt solution).

[0016] 4. The material of this invention maintains superhydrophobicity in acidic / alkaline / high-salt wastewater, making it suitable for complex industrial scenarios; the oil-water separation efficiency does not significantly decrease after 13 cycles, and its lifespan is superior to conventional materials; it covers light oil (n-hexane) to heavy oil (chloroform), with an adsorption capacity as high as 56.84 g / g.

[0017] 5. This invention efficiently separates immiscible oil-water mixtures such as machine tool oil and petrochemical wastewater (>98.36% efficiency); it is resistant to pH 3-11 and high salt corrosion, and is suitable for acidic wastewater scenarios such as electroplating and chemical industries; this invention combines the advantages of fluorine-free design and long cycle life, which can reduce secondary pollution and replacement costs. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process for preparing superhydrophobic melamine sponge according to the present invention.

[0019] Figure 2 The images show the FT-IR spectra of the original sponge and the modified sponge made of phenolic resin@silica@stearic acid@melamine in Example 1.

[0020] Figure 3 XPS images of the original sponge and the modified sponge (phenolic resin@silica@stearic acid@melamine sponge) in Example 1.

[0021] Figure 4 FESEM images of the original melamine sponge (ac), phenolic resin@silica@melamine sponge (df), and the superhydrophobic melamine sponge (gi) obtained in Example 1.

[0022] Figure 5 Droplets of water (stained with methylene blue) and n-hexane (stained with Sudan II) on the surface of the superhydrophobic melamine sponge obtained in Example 1 (water on the left and n-hexane with adsorption traces on the right), and droplets of water in the middle of the superhydrophobic melamine sponge obtained in Example 1.

[0023] Figure 6 The image shows the water contact angle of the superhydrophobic melamine sponge obtained in Example 1.

[0024] Figure 7 These are comparative images of the superhydrophobic melamine sponge obtained in Example 1 and the original melamine sponge in different states in water.

[0025] Figure 8 This is a diagram showing the silver mirror phenomenon of the superhydrophobic melamine sponge obtained in Example 1 in water.

[0026] Figure 9 This is a graph showing the adsorption capacity of the superhydrophobic melamine sponge obtained in Example 1 for different organic solvents or oils.

[0027] Figure 10 The image shows the superhydrophobic melamine sponge obtained in Example 1 adsorbing n-hexane and chloroform (stained with Sudan II).

[0028] Figure 11 The graph shows the separation efficiency of the superhydrophobic melamine sponge obtained in Example 1 for different organic solvent / water mixtures.

[0029] Figure 12 This is a comparison chart showing the adsorption capacity of the superhydrophobic melamine sponge obtained in Example 1 for 13 cycles of adsorption of chloroform and n-hexane.

[0030] Figure 13 The diagram shows the compression cycle of the superhydrophobic melamine sponge obtained in Example 1 (a) and the trend of water contact angle change (b).

[0031] Figure 14 The variation trend of water contact angle of the superhydrophobic melamine sponge obtained in Example 1 when immersed in solutions with different salt concentrations (a), solutions with different pH values ​​(b), and deionized water at different temperatures (c).

[0032] Figure 15 The changes in the shape of water droplets on the surface of the superhydrophobic melamine sponge obtained in Example 1 at different times. Detailed Implementation

[0033] The present invention will be further described below with reference to embodiments, but is not limited thereto. Example 1

[0034] (1) At 51°C, 65 mL of ethanol and 2 mL of ammonia (25 wt%) were mixed evenly. Then, 6.5 mL of LTEOS was added dropwise, stirred for 6 h, centrifuged, washed three times with ethanol, and finally dried at 60°C to obtain 20 nm silica particles.

[0035] 4 mL of TEOS was added to 40 mL of ethanol under stirring at room temperature, followed by 1.6 mL of ammonia (25 wt%), and stirring was maintained for 20 min. The mixture was left to stand for 2 days without stirring to generate uniform silica nanoparticles of 40-80 nm. After centrifugation, the nanoparticles were washed three times with ethanol and finally dried at 60 °C to obtain dry silica nanoparticles of 40-80 nm (average particle size of 60 nm).

[0036] A volume of 1*1*1 cm 3 Pretreated melamine sponges were obtained by sonicating them in ethanol and deionized water for 1 hour each and then drying them at 60°C.

[0037] (2) Add 0.5 g of phenolic resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder. Add 0.05 g of silica particles with an average particle size of 60 nm and 0.05 g of silica particles with an average particle size of 20 nm to 50 mL of ethanol to prepare a silica ethanol solution. Then, immerse four pretreated melamine sponges in the binder and soak them under ultrasonic conditions at a frequency of 40 kHz for 1 h to obtain phenolic resin@melamine sponge. Then, put them into the silica ethanol solution and soak them for 12 h. After soaking, take them out and dry them in an oven at 60 ℃ to obtain phenolic resin@silica@melamine sponge.

[0038] (3) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0039] Figure 2 FT-IR spectra of the original sponge and the modified sponge (phenolic resin@silica@stearic acid@melamine sponge). The 809, 1573, and 3374 cm⁻¹ spectra of the original melamine sponge are shown. -1 The nearby absorption bands are attributed to triazine ring bending, CN stretching, and NH stretching, respectively; at 1326 and 1442 cm⁻¹ -1 The strong bending adsorption peak at 1190 cm⁻¹ is due to the -CH-bending structure. These absorption bands confirm the chemical composition of the melamine sponge. A new peak appears after modification. -1 The peaks near 1296 and 811 cm⁻¹ represent Si-O-Si bonds. -1 The observation of Si-CH3 bonds at the peak values, which contribute to hydrophobicity, indicates the presence of silica nanoparticles on the modified sponge. At 2908, 2843, 1698, and 1463 cm⁻¹, [the following values ​​were observed]. -1Three absorption peaks were observed at the point, which are related to the symmetrical CH stretching vibration, the asymmetrical -CH2- group, and the OCO group, respectively. These are characteristic peaks of stearic acid, indicating that stearic acid exists on the sponge skeleton.

[0040] Figure 3 XPS images of the original and modified melamine sponge (phenolic resin@silica@stearic acid@melamine sponge) are shown. To further determine the changes in the chemical composition of the sponge after each modification, electron binding energies were analyzed by XPS. The figure shows the elemental composition results of the original and modified melamine sponges. The characteristic peaks at 284.80, 398.99, and 532.06 eV are attributed to the C1s, N1s, and O1s characteristic peaks of the original melamine sponge, respectively, which is consistent with other literature reports. Furthermore, the characteristic peaks at 102.08 and 153.98 eV are attributed to Si 2p and Si 2s, indicating the presence of silica.

[0041] Figure 4 These are FE-SEM images of the original melamine sponge, phenolic resin@silica@melamine sponge, and phenolic resin@silica@stearic acid@melamine sponge. To more intuitively observe the surface morphology of the phenolic resin@silica@stearic acid@melamine sponge, FE-SEM was used to study the morphology of the original sponge and the phenolic resin@silica@stearic acid@melamine sponge. The pretreated melamine sponge exhibits a three-dimensional porous structure with a smooth surface. Figure 4 ac). For example Figure 4 (df) Under the action of phenolic resin, nanoparticles are firmly fixed on the surface of the sponge, and the sponge's skeleton is uniformly coated with particles, and these particle protrusions do not block the sponge's pores. These particles create a rough morphology on the sponge surface, providing an important microstructure for enhancing the sponge's hydrophobicity. Figure 4 (gi) After introducing stearic acid into the modified sponge, the surface of the sponge was rougher than that of the unmodified sponge, indicating that the stearic acid was successfully coated onto the sponge. After a series of modifications, the sponge still maintained its unique three-dimensional structure.

[0042] The phenolic resin@silica@stearic acid@melamine sponge exhibits water droplet repulsion, which is related to the introduction of nanoparticle silica and surface free energy stearic acid. Furthermore, when the modified sponge is cut in half, water droplets appear as spherical objects resting on the sponge. This indicates that both the internal and external surfaces of the phenolic resin@silica@stearic acid@melamine sponge have been successfully modified, resulting in superhydrophobic properties. Figure 5 The wettability of the phenolic resin@silica@stearic acid@melamine sponge surface was evaluated by measuring the water contact angle (WCA), and the result was 153.5°. Figure 6 ).

[0043] like Figure 7 As shown, the original sponge and the modified sponge (phenolic resin@silica@stearic acid@melamine) were immersed in water and placed on the water surface and at the bottom of a beaker, respectively. The original sponge absorbed water instantly upon contact with the water surface and sank to the bottom of the beaker; while the modified sponge (phenolic resin@silica@stearic acid@melamine) remained floating on the water surface after contact with water.

[0044] When an external force is applied to push it into the water ( Figure 8 This creates a "silver mirror" effect. This is mainly because the surface of the phenolic resin@silicon dioxide@stearic acid@melamine sponge is covered with many micro and nano materials. When an external force is applied and the sponge is submerged in water, a large amount of air is trapped between the superhydrophobic sponge surface and the surrounding water.

[0045] The modified sponge was immersed in 20 mL of oil or organic solvent (petroleum ether, n-octane, n-hexane, acetone, toluene, DMF, chloroform, carbon tetrachloride) for saturated adsorption. The mass before and after adsorption was measured, and the adsorption capacity can be calculated according to the following equation: Q = (m1 - m0) / m0 Where m0 and m1 are the masses of the modified sponge before and after adsorption, respectively, and Q is the adsorption capacity.

[0046] Test results are as follows Figure 9 As shown, the modified sponge exhibits excellent adsorption capacity, with an adsorption capacity that can reach 23.54 (n-hexane) to 56.84 (trichloromethane) times its own weight.

[0047] Deionized water and organic solvents (n-hexane, chloroform, n-octane, acetone, toluene, DMF, and petroleum ether) were mixed at a volume ratio of 1:1. A modified sponge was added to adsorb the organic solvents. The mass of deionized water before and after separation was measured. The oil-water separation efficiency can be calculated using the following equation: η=m b / m a Where m a m b η represents the mass of deionized water before and after separation, respectively, and η is the oil-water separation efficiency.

[0048] Test results are as follows Figure 11 As shown, the oil-water separation efficiency of the functional sponge phenolic resin@silica@stearic acid@melamine sponge was specifically evaluated by measuring the mass of water before and after gravity separation. The phenolic resin@silica@stearic acid@melamine sponge achieved a separation efficiency of over 98.36% for hexane / water, chloroform / water, n-octane / water, acetone / water, toluene / water, DMF / water, and petroleum ether / water, indicating a very high oil-water separation efficiency.

[0049] The recyclability of the modified sponge was studied through adsorption-desorption experiments. After each saturation adsorption cycle, the sponge was completely compressed and dried before being used in the next cycle. After 13 cycles, the modified sponge still maintained adsorption capacities of 20.6 g / g for hexane and 50.0 g / g for chloroform. Figure 12 Therefore, the superhydrophobic melamine sponge prepared by this invention has excellent durability.

[0050] Elastic deformation-recovery experiments were conducted on a phenolic resin@silica@stearic acid@melamine sponge under a 500 g weight. The water contact angle of the sponge was measured every 20 cycles. Figure 13 As shown, after 140 compressions, the water contact angle of the phenolic resin@silica@stearic acid@melamine sponge decreased slightly, but remained greater than 140°. This is because the strong adhesiveness of the phenolic resin makes it difficult for the nanoparticles loaded on the sponge surface to detach. Therefore, the functional superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge exhibits excellent mechanical stability, enabling it to effectively separate oil and water.

[0051] In practical applications, special absorbent materials are often used in outdoor environments, so extreme environments are common. This necessitates that the prepared functional superhydrophobic materials possess high chemical stability. Therefore, in this experiment, hydrochloric acid solutions, sodium hydroxide solutions, and salt solutions of different pH values ​​were first prepared. Modified sponges were placed in these solutions for 12 hours to evaluate the chemical stability of the functional sponge phenolic resin@silica@stearic acid@melamine sponge. The experimental results are as follows: Figure 14 As shown in (a) and (b), the hydrophobic angle of the phenolic resin@silica@stearic acid@melamine sponge decreased to varying degrees, but it still retained hydrophobicity. Experimental data showed that the functional superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge exhibited good corrosion resistance in strong acid, strong alkali, and salt solutions. Furthermore, in practical applications, ambient temperature has a significant impact on functional materials. Therefore, a high-temperature resistance test was conducted on the phenolic resin@silica@stearic acid@melamine sponge. The experimental results are as follows... Figure 14 As shown in (c), the modified sponge still retains its hydrophobicity after being soaked at different temperatures for 12 hours. Therefore, the experiment proves that the functional superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge has excellent high-temperature stability and is expected to become an applied adsorbent material.

[0052] In addition, adding 0.2 mL of water (stained with methylene blue) to the surface of a phenolic resin@silica@stearic acid@melamine sponge and allowing it to stand for 0 h, 0.5 h, 6 h, and 12 h respectively, can reduce the surface temperature of the sponge. Figure 15It is clear that the water droplets on the sponge surface are spherical. As time goes by, the water droplets gradually decrease in size and darken in color, but still maintain their spherical shape, which shows that the sponge's hydrophobicity does not change over time. Example 2

[0053] (1) The preparation steps of silica nanoparticles and the process of pretreating melamine sponge are the same as in Example 1.

[0054] (2) Add 0.4 g of phenolic resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder. Add 0.05 g of silica particles with an average particle size of 60 nm and 0.05 g of silica particles with an average particle size of 20 nm to 50 mL of ethanol to prepare a silica / ethanol solution. Then immerse the pretreated melamine sponge in the solution and soak it under ultrasonic conditions for 1 h to obtain phenolic resin@melamine sponge. Add 10 mL of ethanol to the prepared silica solution, put the phenolic resin@melamine sponge into the solution, soak it for 12 h, and after soaking, take it out and dry it in an oven at 60 ℃ to obtain phenolic resin@silica@melamine sponge.

[0055] (3) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0056] The modified sponge has a water contact angle of 152°, and adsorption capacities for n-hexane and chloroform are 22.6 g / g and 47.8 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 98.2%. Example 3

[0057] (1) The preparation steps of silica nanoparticles and the process of pretreating melamine sponge are the same as in Example 1.

[0058] (2) Add 0.6 g of phenolic resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder. Add 0.05 g of silica particles with an average particle size of 60 nm and 0.05 g of silica particles with an average particle size of 20 nm to 50 mL of ethanol to prepare a silica ethanol solution. Then immerse the pretreated melamine sponge in the solution and soak it under ultrasonic conditions for 1 h to obtain phenolic resin@melamine sponge. Add 10 mL of ethanol to the prepared silica solution, put the phenolic resin@melamine sponge into the solution, soak it for 12 h, and after soaking, take it out and dry it in an oven at 60 ℃ to obtain phenolic resin@silica@melamine sponge.

[0059] (3) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0060] The modified sponge has a water contact angle of 151°, and adsorption capacities for n-hexane and chloroform are 20.1 g / g and 48.7 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 97.8%. Example 4

[0061] (1) The preparation steps of silica nanoparticles and the process of pretreating melamine sponge are the same as in Example 1.

[0062] (2) Add 0.5 g of phenolic resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder. Add 0.1 g of silica particles with an average particle size of 60 nm and 0.05 g of silica particles with an average particle size of 20 nm to 50 mL of ethanol to prepare a silica ethanol solution. Then immerse the pretreated melamine sponge in the solution and soak it under ultrasonic conditions for 1 h to obtain phenolic resin@melamine sponge. Add 10 mL of ethanol to the prepared silica solution, put the phenolic resin@melamine sponge into the solution, soak it for 12 h, and after soaking, take it out and dry it in an oven at 60 ℃ to obtain phenolic resin@silica@melamine sponge.

[0063] (3) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0064] The modified sponge has a water contact angle of 150°, and adsorption capacities for n-hexane and chloroform are 32.7 g / g and 51.5 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 96.3%. Example 5

[0065] (1) The preparation steps of silica nanoparticles and the process of pretreating melamine sponge are the same as in Example 1.

[0066] (2) Add 0.5 g of phenolic resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder. Add 0.05 g of silica particles with an average particle size of 60 nm and 0.1 g of silica particles with an average particle size of 20 nm to 50 mL of ethanol to prepare a silica ethanol solution. Then immerse the pretreated melamine sponge in the solution and soak it under ultrasonic conditions for 1 h to obtain phenolic resin@melamine sponge. Add 10 mL of ethanol to the prepared silica solution, put the phenolic resin@melamine sponge into the solution, soak it for 12 h, and after soaking, take it out and dry it in an oven at 60 ℃ to obtain phenolic resin@silica@melamine sponge.

[0067] (3) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0068] The modified sponge has a water contact angle of 150°, and adsorption capacities for n-hexane and chloroform are 19.7 g / g and 53.1 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 97.4%. Example 6

[0069] (1) The preparation steps of silica nanoparticles and the process of pretreating melamine sponge are the same as in Example 1.

[0070] (2) Add 0.5 g of phenolic resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder. Add 0.05 g of silica particles with an average particle size of 60 nm and 0.05 g of silica particles with an average particle size of 20 nm to 50 mL of ethanol to prepare a silica ethanol solution. Then immerse the pretreated melamine sponge in the solution and soak it under ultrasonic conditions for 1 h to obtain phenolic resin@melamine sponge. Add 10 mL of ethanol to the prepared silica solution, put the phenolic resin@melamine sponge into the solution, soak it for 6 h, and after soaking, take it out and dry it in an oven at 60 ℃ to obtain phenolic resin@silica@melamine sponge.

[0071] (3) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0072] The modified sponge has a water contact angle of 148°, and adsorption capacities for n-hexane and chloroform are 20.9 g / g and 54.2 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 95.8%. Example 7

[0073] (1) The preparation steps of silica nanoparticles and the process of pretreating melamine sponge are the same as in Example 1.

[0074] (2) Add 0.5 g of phenolic resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder. Add 0.05 g of silica particles with an average particle size of 60 nm and 0.05 g of silica particles with an average particle size of 20 nm to 50 mL of ethanol to prepare a silica ethanol solution. Then immerse the pretreated melamine sponge in the solution and soak it under ultrasonic conditions for 1 h to obtain phenolic resin@melamine sponge. Add 10 mL of ethanol to the prepared silica solution, put the phenolic resin@melamine sponge into the solution, soak it for 18 h, and after soaking, take it out and dry it in an oven at 60 ℃ to obtain phenolic resin@silica@melamine sponge.

[0075] (3) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0076] The modified sponge has a water contact angle of 149°, and adsorption capacities for n-hexane and chloroform are 21.8 g / g and 53.8 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 96.3%. Example 8

[0077] (1)-(2) are the same as in Example 1.

[0078] (3) Prepare a 12.5 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0079] The modified sponge has a water contact angle of 153°, and adsorption capacities for n-hexane and chloroform are 18.1 g / g and 48.4 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 95.4%. Example 9

[0080] (1)-(2) are the same as in Example 1.

[0081] (3) Prepare a 7.5 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain a superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0082] The modified sponge has a water contact angle of 151°, and adsorption capacities for n-hexane and chloroform are 21.1 g / g and 51.4 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 97.7%. Example 10

[0083] (1)-(2) are the same as in Example 1.

[0084] (3) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 2 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0085] The modified sponge has a water contact angle of 147°, and adsorption capacities for n-hexane and chloroform are 20.5 g / g and 53.7 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 97.0%. Example 11

[0086] (1)-(2) are the same as in Example 1.

[0087] (3) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 6 h, and then dry it in an oven at 60 ℃ to obtain a superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0088] The modified sponge has a water contact angle of 151°, and adsorption capacities for n-hexane and chloroform are 19.6 g / g and 52.0 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 98.1%. Comparative Example 1

[0089] (1) 20 nm silicon dioxide particles were obtained as in Example 1.

[0090] (2) Mix 40 mL of ethanol and 4 mL of deionized water, add 1.2 mL of 25% ammonia water under magnetic stirring, slowly add 2 mL of TEOS dropwise over 5 min, and continue stirring at 25 °C for 2 h to obtain a milky white sol; add 0.1 M HCl to neutralize to pH≈7 to terminate the reaction, centrifuge at 10000 rpm for 10 min to collect the precipitate, wash twice with ethanol and once with deionized water, and vacuum dry at 60 °C for 12 h to obtain silica nanoparticles with an average particle size of about 30 nm.

[0091] (3) Add 0.5 g of phenolic resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder. Add 0.05 g of 20 nm silica particles and 0.05 g of 30 nm silica particles to 50 mL of ethanol to prepare a 20 nm silica / 30 nm silica ethanol solution. Then immerse the pretreated melamine sponge in the binder and soak it under ultrasonic conditions for 1 h to obtain phenolic resin@melamine sponge. Then immerse it in the silica ethanol solution for 12 h. After soaking, take it out and dry it in an oven at 60 ℃ to obtain phenolic resin@silica@melamine sponge.

[0092] (4) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@silica@stearic acid@melamine sponge.

[0093] The modified sponge has a water contact angle of 151°, and adsorption capacities for n-hexane and chloroform are 24.6 g / g and 50.1 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 96.7%. Comparative Example 2

[0094] (1) Add 0.5 g of phenolic resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder. Then immerse the pretreated melamine sponge in it and soak it under ultrasonic conditions for 1 h to obtain phenolic resin@melamine sponge. Put the phenolic resin@melamine sponge into it and soak it for 12 h. After soaking, take it out and dry it in an oven at 60 ℃ to obtain phenolic resin@melamine sponge.

[0095] (2) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge phenolic resin@stearic acid@melamine sponge.

[0096] The modified sponge has a water contact angle of 142°, and adsorption capacities for n-hexane and chloroform are 20.8 g / g and 43.1 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 96.9%. Comparative Example 3

[0097] (1) The preparation method of silica nanoparticles is the same as in Example 1.

[0098] (2) Add 0.5 g of epoxy resin and 100 mL of acetone to a beaker and stir for 30 min to obtain a stable binder. Prepare a silica solution by mixing silica particles with an average particle size of 60 nm and 20 nm at a mass ratio of 1:1 with a total mass of 0.1 g. Then immerse the pretreated melamine sponge in the solution and soak it under ultrasonic conditions for 1 h to obtain epoxy resin@melamine sponge. Add 10 mL of ethanol to the prepared silica solution, put the epoxy resin@melamine sponge into it, soak it for 12 h, and after soaking, take it out and dry it in an oven at 60 ℃ to obtain epoxy resin@silica@melamine sponge.

[0099] (3) Prepare a 10 mM stearic acid-ethanol solution, dissolve it by sonication, soak the dried epoxy resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain superhydrophobic sponge epoxy resin@silica@stearic acid@melamine sponge.

[0100] The modified sponge has a water contact angle of 151°, and adsorption capacities for n-hexane and chloroform are 18.12 g / g and 49.6 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 98.0%. Comparative Example 4

[0101] (1)-(2) are the same as in Example 1.

[0102] (3) Prepare a 10 mM oleic acid-ethanol solution, dissolve it by sonication, soak the dried phenolic resin@silica@melamine sponge in it for 4 h, and then dry it in an oven at 60 ℃ to obtain a superhydrophobic sponge phenolic resin@silica@oleic acid@melamine sponge.

[0103] The modified sponge has a water contact angle of 143°, and adsorption capacities for n-hexane and chloroform are 17.6 g / g and 45.5 g / g, respectively. The separation efficiency of the n-hexane / water mixture is 97.6%.

[0104] 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 method for preparing a superhydrophobic melamine sponge with roughness constructed from multiple particles, characterized in that, The preparation method steps are as follows: (1) Phenolic resin and acetone are mixed and stirred to obtain a stable adhesive. The pretreated melamine sponge is immersed in it and soaked under ultrasonic conditions to obtain phenolic resin@melamine sponge. (2) Mix silica nanoparticles of different sizes evenly in ethanol, immerse phenolic resin@melamine sponge in it, remove and dry after immersion to obtain phenolic resin@silica@melamine sponge; (3) Prepare a stearic acid-ethanol solution, immerse the dried phenolic resin@silica@melamine sponge in it, take it out and dry it to obtain a superhydrophobic melamine sponge based on the roughness of multiple particles.

2. The method for preparing superhydrophobic melamine sponge as described in claim 1, characterized in that, In step (1), the pretreated melamine sponge was obtained by sonicating in ethanol and deionized water for 1 hour each, followed by drying at 60 °C. Each sponge had a volume of 1*1*1 cm. 3 The number of units invested is 4.

3. The method for preparing superhydrophobic melamine sponge according to claim 1, characterized in that, In step (1), the concentration of phenolic resin in acetone is 4-6 g / L, and the mixture is magnetically stirred for 30 min.

4. The method for preparing superhydrophobic melamine sponge according to claim 1, characterized in that, In step (2), the particle sizes of the silica nanoparticles of different sizes are 20 nm and 40-80 nm, respectively, and the mass ratio of the two is 1:0.5-2.

5. The method for preparing superhydrophobic melamine sponge according to claim 1, characterized in that, In step (2), the soaking time is 6-18 hours.

6. The method for preparing superhydrophobic melamine sponge according to claim 1, characterized in that, In step (3), the concentration of stearic acid-ethanol solution is 7.5-12.5 mM, and the soaking time is 2-6 h.

7. A superhydrophobic melamine sponge prepared according to any one of claims 1-6.

8. An application of a superhydrophobic melamine sponge prepared according to any one of claims 1-6, characterized in that, The superhydrophobic melamine sponge is used to separate organic solvents and oil compounds.

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