Bimetal MOF (Metal Organic Framework) photo-thermal super-hydrophobic polyurethane sponge as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of oil-water separation materials, and particularly discloses a bimetallic MOF photo-thermal super-hydrophobic polyurethane sponge and a preparation method and application thereof. Bimetal MOF photo-thermal super-hydrophobic polyurethane sponge ODTMS (at) Ag / Co-MOF (at) PDA (at) PU is prepared by adopting an in-situ growth method, a PDA layer is formed on the surface of the sponge through dopamine oxidation auto-agglutination, and then Ag-MOF and Co-MOF are grown on the sponge in situ by using the same organic ligand. In order to further enhance the hydrophobic property of the MOF sponge, long-chain alkyl trimethoxy silane is hydrolyzed and condensed, and a non-toxic low-surface-energy polysiloxane adhesive layer is formed on the surface of the sponge. The process is simple and environment-friendly, the raw materials are easy to obtain, the modified sponge has excellent oil-water separation performance, reusability, environmental stability, photo-thermal performance and micro-plastic absorption capacity, and the material can be applied to marine oil spill, micro-plastic absorption and sewage treatment.

Description

Technical Field

[0001] This invention belongs to the field of oil-water separation materials technology, and specifically discloses a bimetallic MOF photothermal superhydrophobic polyurethane sponge, its preparation method and application. Background Technology

[0002] In recent years, societal progress in production and daily life has exacerbated the serious problem of water pollution, posing a significant threat to natural ecosystems and human health. This threat primarily stems from the rising incidence of water pollution-related diseases caused by a variety of sources, such as oily wastewater, heavy metals, microplastics, and dyes.

[0003] Among these pollutants, oily wastewater is considered a particularly harmful environmental hazard. Traditional water purification technologies, including in-situ incineration, chemical dispersion, biodegradation, and photocatalysis, often fall short in terms of efficiency, sustainability, and energy consumption, frequently leading to secondary pollution. Compared to these traditional water purification technologies, physical adsorption offers advantages such as simple operation, low raw material and manufacturing costs, and environmental friendliness, attracting researchers' attention. Due to their excellent absorption capacity and large absorption volume, porous materials are highly favored among the adsorbent materials required for physical adsorption methods. Among them, polyurethane sponges have attracted widespread attention due to their chemical stability, excellent elasticity, high porosity, superior absorption efficiency, corrosion resistance, and cost-effectiveness. However, polyurethane sponges lack the specificity required for direct oil-water separation, and their performance is generally average, lacking the special properties for efficiently removing microplastics, organic dyes, etc. Summary of the Invention

[0004] To address the technical problems identified in the background section, this invention provides a green, environmentally friendly, simple, and easy-to-operate method for preparing a bimetallic MOF photothermal superhydrophobic polyurethane sponge. This sponge is a superhydrophobic / superoleophilic material that is resistant to acids and alkalis, corrosion, and compression, exhibits good reusability, and can efficiently perform continuous oil-water separation. Furthermore, this composite sponge possesses excellent photothermal properties and can effectively absorb microplastics from wastewater, thus mitigating the environmental challenges mentioned in the background section to some extent.

[0005] Specifically, the method of the present invention for preparing bimetallic MOF photothermal superhydrophobic polyurethane sponges is as follows: (1) Cut the untreated PU into 1×1×1cm pieces. 3 The sponge was shaped into cubes and ultrasonically cleaned with ethanol and deionized water for 30 minutes each to remove impurities from the PU surface. After cleaning, the sponge was placed in a forced-air drying oven to dry for later use.

[0006] (2) 0.15 g of dopamine and pretreated PU were added sequentially to 125 mL of buffer solution (Tris-HCl, pH=8.5) and stirred at room temperature for 24 h at 180 rpm using a magnetic stirrer. After stirring, the PU with the PDA layer on the surface was removed and rinsed repeatedly with anhydrous ethanol and deionized water until the solution was clear. Finally, the sponge was placed in a 60 °C drying oven for 12 h to obtain the PDA@PU sample.

[0007] (3) Silver nitrate and cobalt nitrate hexahydrate were dissolved in 100 mL of deionized water to prepare solution A. 2-Methylimidazole was dissolved in 80 mL of anhydrous ethanol to prepare solution B. Then, solution A was slowly added to solution B under stirring at 500 rpm, followed by the addition of PDA@PU. The reaction was carried out in an oil bath for 24 h. After the reaction was completed, the product was washed and dried to obtain Ag / Co-MOF@PDA@PU.

[0008] The mass ratio of silver nitrate, cobalt nitrate hexahydrate, and 2-methylimidazole is 0.4-0.8: 0.12-0.36: 0.8-1.8.

[0009] (4) Add 0.3 mL of acetic acid and 30 mL of ethanol solution (95%) to a beaker and stir well. Slowly add 0.5-1.5 mL of long-chain alkyltrimethoxysilane and continue stirring at room temperature for 3 h. Finally, add Ag / Co-MOF@PDA@PU and continue stirring at 180 rpm at room temperature for 3 h. After stirring, dry in a 60℃ oven for 6 h to obtain the bimetallic MOF photothermal superhydrophobic polyurethane sponge ODTMS@Ag / Co-MOF@PDA@PU.

[0010] Long-chain alkyltrimethoxysilanes are: octadecyltrimethoxysilane, dodecyltrimethoxysilane, or hexadecyltrimethoxysilane.

[0011] The advantages of this invention compared to the prior art are: 1. The modification process of this invention is simple, convenient, and low in cost. The raw materials are non-toxic, harmless, and environmentally friendly.

[0012] 2. The sponge of this invention has excellent superhydrophobicity (water contact angle of 160.2°), high oil absorption capacity (28.1-81.5 g / g), excellent microplastic absorption capacity (saturated absorption rate of 0.82 g / g, 0.63 g / g, and 0.68 g / g for PP-150mm, PVC-50mm, and PE-50mm, respectively), and good photothermal properties.

[0013] 3. The superhydrophobic melamine sponge prepared by this invention has excellent oil-water separation performance, reusability, and environmental stability. Attached Figure Description

[0014] Figure 1 The images show a comparison of the original sponge and the composite sponge of Example 1 of this invention using FESEM.

[0015] Figure 2 (a) is a water contact angle test of water droplets on the original sponge and the composite sponge of Example 1 of the present invention, and a state diagram of water droplets and some oil droplets on the surfaces of both. (b) is a state diagram of water droplets on the cross section of the composite sponge of Example 1 of the present invention. (c) is a picture of the silver mirror phenomenon of the composite sponge of Example 1 of the present invention in water. (d) is a state diagram of the original sponge sinking in water and the composite sponge of Example 1 of the present invention floating on water. (e) is a state diagram of water droplets on the composite sponge of Example 1 of the present invention changing over time.

[0016] Figure 3 This describes the absorption capacity of the composite sponge in Example 1 of the present invention for different organic solvents / oils.

[0017] Figure 4 This is a graph showing the hydrophobic angle data of the composite sponge in Example 1 of the present invention after soaking for 12 hours at different pH levels.

[0018] Figure 5 This is a graph showing the hydrophobic angle data of the composite sponge in Example 1 of the present invention after soaking in different salt concentrations for 12 hours.

[0019] Figure 6 The composite sponge of Example 1 of this invention has a strength of 1.5 Kw / m. 2 The surface temperature changes over time to reach its peak under simulated solar xenon lamp irradiation.

[0020] Figure 7 This is a process flow diagram of the present invention. Detailed Implementation

[0021] The present invention will be further described below with reference to embodiments, but is not limited thereto. Example 1

[0022] (1) Cut the untreated PU into 1×1×1cm pieces. 3 The sponge was shaped into cubes and ultrasonically cleaned with ethanol and deionized water for 30 minutes each to remove impurities from the PU surface. After cleaning, the sponge was placed in a 60℃ forced-air drying oven for 12 hours to dry. (2) 0.15 g of dopamine and pretreated PU were added to 125 mL of buffer solution (Tris-HCl, pH=8.5) and stirred at room temperature at 180 rpm for 24 h using a magnetic stirrer. After stirring, the PU with PDA layer on the surface was taken out and rinsed repeatedly with anhydrous ethanol and deionized water until the solution was clear. Finally, the sponge was placed in a 60℃ drying oven for 12 h to obtain the PDA@PU sample. (3) Dissolve 0.6 g silver nitrate and 0.24 g cobalt nitrate hexahydrate in 100 mL deionized water to prepare solution A. Dissolve 1.31 g 2-methylimidazole in 80 mL anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction is carried out in an oil bath at 90 °C for 24 h. After the reaction is complete, rinse with deionized water until no powder particles fall off when the sponge is placed in the water, and the water is clear and not turbid. Dry the product to obtain Ag / Co-MOF@PDA@PU.

[0023] Figure 1 The images show a comparison of FESEM images of the original sponge and the composite sponge of Example 1 of this invention. As can be seen from the images, the composite sponge of this invention has bulk Co-MOF nanoparticles and strip Ag-MOF nanoparticles loaded on its skeleton. The loading is relatively large and uniform, which proves the success of the in-situ growth method for loading the two types of nanoparticles.

[0024] (4) Add 0.3 mL of acetic acid and 30 mL of ethanol solution (95%) to a beaker and stir well. Add 1 mL of octadecyltrimethoxysilane (ODTMS) dropwise at a rate of one drop per second and continue stirring at room temperature for 3 h. Finally, add Ag / Co-MOF@PDA@PU and continue stirring at 180 rpm at room temperature for 3 h. After stirring, dry in a 60℃ forced-air drying oven for 6 h to obtain the bimetallic MOF photothermal superhydrophobic polyurethane sponge ODTMS@Ag / Co-MOF@PDA@PU.

[0025] (i) Further study on the hydrophobic properties, saturated adsorption capacity, and environmental stability of the superhydrophobic melamine prepared in this invention to evaluate its actual oil-water separation capability: (1) Hydrophobic properties Figure 2(a) shows the water contact angle test (160.2°) of water droplets on the original sponge and the composite sponge of Example 1 of the present invention, as well as the state diagrams of water droplets and some oil droplets on both surfaces. (b) shows the state diagram of water droplets on the cross-section of the composite sponge of Example 1 of the present invention, where the water droplets appear as spherical objects on the surface. (c) shows the silver mirror phenomenon of the composite sponge of Example 1 of the present invention in water. (d) shows the original sponge sinking in water while the composite sponge of Example 1 of the present invention floats on the water. (e) shows the state diagram of water droplets on the composite sponge of Example 1 of the present invention over time, where it can be seen that the water droplets always remain spherical on the sponge surface over time. All of the above demonstrate the excellent superhydrophobic properties of the composite sponge.

[0026] (2) Adsorption capacity for oily substances and organic solvents like Figure 3 As shown, the composite sponge of the present invention has an adsorption capacity of 28.7 g / g (n-hexane) and 76.2 g / g (chloroform) for oil and organic solvents, respectively, and has good oil absorption capacity.

[0027] (3) Environmental stability The composite sponge was soaked in acidic or alkaline solutions with pH values ​​of 1, 3, 5, 7, 9, 11, and 13 for 12 hours. The sponge was then removed, rinsed with anhydrous ethanol, dried, and its water contact angle was measured. Figure 4 The composite sponge was soaked in NaCl solutions with concentrations of 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0% for 12 hours. The sponge was then removed, rinsed with anhydrous ethanol, dried, and the water contact angle was measured. Figure 5 The composite sponge can maintain a superhydrophobic state of over 150° under various environments, proving its good environmental stability.

[0028] (II) The photothermal properties of the composite sponge play a crucial role in its absorption of high-viscosity heavy oil, and are of great significance in practical applications. The photothermal properties of the composite sponge of this invention were studied using the following experiments: The composite sponge was placed in an area with a strength of 1.5 kW / m². 2 The surface temperature was measured and its stable peak value was determined by irradiating the material under a xenon lamp simulating sunlight for 3 minutes using an infrared thermal imaging instrument. Figure 6 As shown, the composite sponge can quickly reach a peak temperature of 82.3℃ after 30 seconds of irradiation, proving that the composite sponge has good photothermal properties.

[0029] (III) Water pollution caused by microplastics poses a significant threat to natural ecosystems and human health. Therefore, the microplastic removal capacity of the composite sponge of this invention was investigated: Typical microplastics PP-150mm (microplastic particle size 150mm), PVC-50mm, and PE-50mm were dissolved in toluene oil phase at 100℃. A composite sponge, weighed as m1, was immersed in the oil phase for absorption in toluene containing dissolved microplastic particles. After absorption saturation, the sponge was dried and weighed as m2. The microplastic absorption rate of the sponge is represented by Q and can be calculated using the following formula: Q = (m2 - m1) / m1 Calculations showed that the saturated absorption rates of the composite sponge for PP-150mm, PVC-50mm, and PE-50mm were 0.82 g / g, 0.63 g / g, and 0.68 g / g, respectively, indicating good microplastic absorption capacity. Example 2

[0030] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Dissolve 0.4 g silver nitrate and 0.24 g cobalt nitrate hexahydrate in 100 mL deionized water to prepare solution A. Dissolve 1.02 g 2-methylimidazole in 80 mL anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction is carried out in an oil bath at 90 °C for 24 h. After the reaction is complete, wash and dry the product to obtain Ag / Co-MOF@PDA@PU; (4) The preparation steps of ODTMS@Ag / Co-MOF@PDA@PU are the same as step (4) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 30.2 g / g for hexane and 78.9 g / g for chloroform, with a hydrophobic angle of 156.7º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.80 g / g, 0.61 g / g, and 0.65 g / g, respectively. The composite sponge also achieves a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 63.8℃, indicating poor photothermal performance. Example 3

[0031] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Dissolve 0.8 g silver nitrate and 0.24 g cobalt nitrate hexahydrate in 100 mL deionized water to prepare solution A. Dissolve 1.6 g 2-methylimidazole in 80 mL anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction was carried out in an oil bath at 90 °C for 24 h. After the reaction was completed, the product was washed and dried to obtain Ag / Co-MOF@PDA@PU; (4) The preparation steps of ODTMS@Ag / Co-MOF@PDA@PU are the same as step (4) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 26.5 g / g for hexane and 73.8 g / g for chloroform, with a hydrophobic angle of 158.6º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.81 g / g, 0.61 g / g, and 0.66 g / g, respectively. The composite sponge has a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 83.4℃, indicating good photothermal performance. Example 4

[0032] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Dissolve 0.4 g silver nitrate and 0.12 g cobalt nitrate hexahydrate in 100 mL deionized water to prepare solution A. Dissolve 0.8 g 2-methylimidazole in 80 mL anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction is carried out in an oil bath at 90 °C for 24 h. After the reaction is complete, wash and dry the product to obtain Ag / Co-MOF@PDA@PU; (4) The preparation steps of ODTMS@Ag / Co-MOF@PDA@PU are the same as step (4) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 30.8 g / g for hexane and 79.4 g / g for chloroform, with a hydrophobic angle of 156.6º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.62 g / g, 0.42 g / g, and 0.45 g / g, respectively. The composite sponge also achieves a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 62.6℃, indicating poor photothermal performance. Example 5

[0033] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Dissolve 0.6 g silver nitrate and 0.12 g cobalt nitrate hexahydrate in 100 mL deionized water to prepare solution A. Dissolve 1.09 g 2-methylimidazole in 80 mL anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction is carried out in an oil bath at 90 °C for 24 h. After the reaction is complete, wash and dry the product to obtain Ag / Co-MOF@PDA@PU; (4) The preparation steps of ODTMS@Ag / Co-MOF@PDA@PU are the same as step (4) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 29.8 g / g for hexane and 78.2 g / g for chloroform, with a hydrophobic angle of 157.8º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.64 g / g, 0.45 g / g, and 0.47 g / g, respectively. The composite sponge also achieves a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value are 80.5℃, indicating good photothermal performance. Example 6

[0034] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Dissolve 0.8 g silver nitrate and 0.12 g cobalt nitrate hexahydrate in 100 mL deionized water to prepare solution A. Dissolve 1.38 g 2-methylimidazole in 80 mL anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction is carried out in an oil bath at 90 °C for 24 h. After the reaction is complete, wash and dry the product to obtain Ag / Co-MOF@PDA@PU; (4) The preparation steps of ODTMS@Ag / Co-MOF@PDA@PU are the same as step (4) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 27.8 g / g for hexane and 76.6 g / g for chloroform, with a hydrophobic angle of 158.8º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.65 g / g, 0.46 g / g, and 0.48 g / g, respectively. The composite sponge also achieves a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 83.2℃, indicating good photothermal performance. Example 7

[0035] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Dissolve 0.4 g silver nitrate and 0.36 g cobalt nitrate hexahydrate in 100 mL deionized water to prepare solution A. Dissolve 1.24 g 2-methylimidazole in 80 mL anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction is carried out in an oil bath at 90 °C for 24 h. After the reaction is complete, wash and dry the product to obtain Ag / Co-MOF@PDA@PU; (4) The preparation steps of ODTMS@Ag / Co-MOF@PDA@PU are the same as step (4) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 28.6 g / g for hexane and 77.6 g / g for chloroform, with a hydrophobic angle of 157.8º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.82 g / g, 0.63 g / g, and 0.66 g / g, respectively. The composite sponge also achieves a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 63.9℃, indicating poor photothermal performance. Example 8

[0036] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Dissolve 0.6 g silver nitrate and 0.36 g cobalt nitrate hexahydrate in 100 mL deionized water to prepare solution A. Dissolve 1.53 g 2-methylimidazole in 80 mL anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction is carried out in an oil bath at 90 °C for 24 h. After the reaction is complete, wash and dry the product to obtain Ag / Co-MOF@PDA@PU; (4) The preparation steps of ODTMS@Ag / Co-MOF@PDA@PU are the same as step (4) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 26.4 g / g for hexane and 74.8 g / g for chloroform, with a hydrophobic angle of 158.2º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.82 g / g, 0.64 g / g, and 0.66 g / g, respectively. The composite sponge also achieves a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value are 82.5℃, indicating good photothermal performance. Example 9

[0037] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Dissolve 0.8 g silver nitrate and 0.36 g cobalt nitrate hexahydrate in 100 mL deionized water to prepare solution A. Dissolve 1.82 g 2-methylimidazole in 80 mL anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction was carried out in an oil bath at 90 °C for 24 h. After the reaction was completed, the product was washed and dried to obtain Ag / Co-MOF@PDA@PU; (4) The preparation steps of ODTMS@Ag / Co-MOF@PDA@PU are the same as step (4) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 23.2 g / g for hexane and 72.8 g / g for chloroform, with a hydrophobic angle of 158.4º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.83 g / g, 0.64 g / g, and 0.67 g / g, respectively. The composite sponge has a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 83.6℃, ​​indicating good photothermal performance. Example 10

[0038] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) The preparation steps of Ag / Co-MOF@PDA@PU are the same as step (3) in Example 1; (4) Add 0.3 mL of acetic acid and 30 mL of ethanol solution (95%) to a beaker and stir well. Slowly add 0.5 mL of octadecyltrimethoxysilane (ODTMS) and continue stirring at room temperature for 3 h. Finally, add Ag / Co-MOF@PDA@PU and continue stirring at 180 rpm at room temperature for 3 h. After stirring, dry in a 60℃ oven for 6 h to obtain the bimetallic MOF photothermal superhydrophobic polyurethane sponge ODTMS@Ag / Co-MOF@PDA@PU.

[0039] The composite sponge exhibits saturated oil absorption capacities of 28.9 g / g for hexane and 76.6 g / g for chloroform, with a hydrophobic angle of 156.4º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.82 g / g, 0.63 g / g, and 0.68 g / g, respectively. The composite sponge has a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 82.1℃, indicating good photothermal performance. Example 11

[0040] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) The preparation steps of Ag / Co-MOF@PDA@PU are the same as step (3) in Example 1; (4) Add 0.3 mL of acetic acid and 30 mL of ethanol solution (95%) to a beaker and stir well. Slowly add 1.5 mL of octadecyltrimethoxysilane (ODTMS) and continue stirring at room temperature for 3 h. Finally, add Ag / Co-MOF@PDA@PU and continue stirring at 180 rpm at room temperature for 3 h. After stirring, dry in a 60℃ oven for 6 h to obtain the bimetallic MOF photothermal superhydrophobic polyurethane sponge ODTMS@Ag / Co-MOF@PDA@PU.

[0041] The composite sponge exhibits saturated oil absorption capacities of 28.6 g / g for hexane and 76.0 g / g for chloroform, with a hydrophobic angle of 158.6º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.82 g / g, 0.63 g / g, and 0.68 g / g, respectively. The composite sponge has a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 82.3℃, indicating good photothermal performance. Example 12

[0042] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) The preparation steps of Ag / Co-MOF@PDA@PU are the same as step (3) in Example 1; (4) Add 0.3 mL of acetic acid and 30 mL of ethanol solution (95%) to a beaker and stir well. Slowly add 1 mL of hexadecyltrimethoxysilane (HDTMS) and continue stirring at room temperature for 3 h. Finally, add Ag / Co-MOF@PDA@PU and continue stirring at 180 rpm at room temperature for 3 h. After stirring, dry in a 60℃ oven for 6 h to obtain the bimetallic MOF photothermal superhydrophobic polyurethane sponge HDTMS@Ag / Co-MOF@PDA@PU.

[0043] The composite sponge exhibits saturated oil absorption capacities of 28.7 g / g for hexane and 76.3 g / g for chloroform, with a hydrophobic angle of 158.8º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.80 g / g, 0.60 g / g, and 0.67 g / g, respectively. The composite sponge has a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 81.6℃, indicating good photothermal performance. Example 13

[0044] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) The preparation steps of Ag / Co-MOF@PDA@PU are the same as step (3) in Example 1; (4) Add 0.3 mL of acetic acid and 30 mL of ethanol solution (95%) to a beaker and stir until homogeneous. Slowly add 1 mL of dodecyltrimethoxysilane (12-TMOS) and continue stirring at room temperature for 3 h. Finally, add Ag / Co-MOF@PDA@PU and continue stirring at 180 rpm at room temperature for 3 h for dip coating. After stirring, dry in a 60℃ forced-air drying oven for 6 h to obtain bimetallic MOF photothermal superhydrophobic polyurethane sponge 12-TMOS@Ag / Co-MOF@PDA@PU.

[0045] The composite sponge exhibits saturated oil absorption capacities of 28.7 g / g for hexane and 76.3 g / g for chloroform, with a hydrophobic angle of 157.2º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.79 g / g, 0.59 g / g, and 0.66 g / g, respectively. The composite sponge achieves a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value are 80.4℃, indicating good photothermal performance. Comparative Example 1

[0046] (1) The PU preparation steps are the same as those in Example 1 (1); (2) Solution A was prepared by dissolving 0.6 g silver nitrate and 0.24 g cobalt nitrate hexahydrate in 100 mL deionized water. Solution B was prepared by dissolving 1.31 g 2-methylimidazole in 80 mL anhydrous ethanol. Solution A was then slowly added to solution B at a rate of 5 mL / s under stirring at 500 rpm, followed by the addition of PU. The reaction was carried out in an oil bath at 90 °C for 24 h. After the reaction was completed, the product was washed and dried to obtain Ag / Co-MOF@PU.

[0047] (3) The preparation steps of ODTMS@Ag / Co-MOF@PU are the same as those in Example 1 (4). The composite sponge exhibits saturated oil absorption capacities of 15.4 g / g for hexane and 38.6 g / g for chloroform, with a hydrophobic angle of 154.6º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.65 g / g, 0.42 g / g, and 0.45 g / g, respectively. The composite sponge has a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 54.6℃, indicating poor photothermal performance. Comparative Example 2

[0048] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Add 0.3 mL of acetic acid and 30 mL of ethanol solution (95%) to a beaker and stir well. Slowly add 1 mL of octadecyltrimethoxysilane (ODTMS) and continue stirring at room temperature for 3 h. Finally, add PDA@PU and continue stirring at 180 rpm at room temperature for 3 h for dip coating. After stirring, dry in a 60℃ forced-air drying oven for 6 h to obtain ODTMS@PDA@PU.

[0049] The composite sponge exhibits saturated oil absorption capacities of 34.3 g / g for hexane and 85.7 g / g for chloroform, with a hydrophobic angle of 158.7º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.12 g / g, 0.08 g / g, and 0.06 g / g, respectively. The composite sponge also achieves a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 58.5℃, indicating poor photothermal performance. Comparative Example 3

[0050] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) The preparation steps of Ag / Co-MOF@PDA@PU are the same as step (3) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 28.9 g / g for hexane and 76.6 g / g for chloroform, with a hydrophobic angle of 0º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.78 g / g, 0.58 g / g, and 0.66 g / g, respectively. The composite sponge achieves a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value are 80.4℃, indicating good photothermal performance. Comparative Example 4

[0051] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Dissolve 0.6 g of silver nitrate in 100 mL of deionized water to prepare solution A. Dissolve 0.87 g of 2-methylimidazole in 80 mL of anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction was carried out in an oil bath at 90 °C for 24 h. After the reaction was completed, the product was washed and dried to obtain Ag-MOF@PDA@PU; (4) The preparation steps of ODTMS@Ag-MOF@PDA@PU are the same as step (4) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 33.6 g / g for hexane and 83.3 g / g for chloroform, with a hydrophobic angle of 158.9º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.18 g / g, 0.13 g / g, and 0.09 g / g, respectively. The composite sponge has a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 75.6℃, indicating good photothermal performance. Comparative Example 5

[0052] (1) The PU preparation steps are the same as those in Example 1 (1); (2) The preparation steps of PDA@PU are the same as step (2) in Example 1; (3) Dissolve 0.24 g of cobalt nitrate hexahydrate in 100 mL of deionized water to prepare solution A. Dissolve 0.44 g of 2-methylimidazole in 80 mL of anhydrous ethanol to prepare solution B. Then, under stirring at 500 rpm, slowly add solution A to solution B at a rate of 5 mL / s, followed by the addition of PDA@PU. The reaction was carried out in an oil bath at 90 °C for 24 h. After the reaction was completed, the product was washed and dried to obtain Co-MOF@PDA@PU; (4) The preparation steps of ODTMS@Co-MOF@PDA@PU are the same as step (4) in Example 1; The composite sponge exhibits saturated oil absorption capacities of 33.9 g / g for hexane and 83.8 g / g for chloroform, with a hydrophobic angle of 158.2º. Its saturated absorption rates for PP-150mm, PVC-50mm, and PE-50mm are 0.78 g / g, 0.58 g / g, and 0.62 g / g, respectively. The composite sponge also achieves a strength of 1.5 kW / m². 2 Under simulated solar xenon lamp irradiation, the surface temperature change and its stable peak value were 62.6℃, indicating poor photothermal performance.

Claims

1. A bimetallic MOF photothermal superhydrophobic polyurethane sponge, characterized in that: The bimetallic MOF photothermal super-hydrophobic polyurethane sponge is prepared by dopamine oxidation self-polymerization on the sponge surface to form a PDA layer, and then Ag-MOF and Co-MOF are grown in situ on the sponge using the same organic ligand to prepare the bimetallic MOF photothermal super-hydrophobic polyurethane sponge ODTMS@Ag / Co-MOF@PDA@PU.

2. The bimetallic MOF photothermal superhydrophobic polyurethane sponge of claim 1, wherein: The preparation method of the polyurethane sponge comprises the following steps: (1) The PU is ultrasonically cleaned and then dried for standby; (2) Dopamine DA and the PU of step (1) are added into a buffer solution and stirred for coating, and then taken out, washed with anhydrous ethanol and deionized water until the solution is clear, and dried to obtain PDA@PU; (3) Silver nitrate and cobalt nitrate hexahydrate are dissolved in deionized water to obtain solution A; 2-methylimidazole is dissolved in anhydrous ethanol to obtain solution B; then, solution A is added to solution B under stirring, and the PDA@PU of step (2) is added, and after reaction in an oil bath, the product is washed and dried to obtain Ag / Co-MOF@PDA@PU; (4) Acetic acid and ethanol are added into a beaker and stirred uniformly, long-chain alkyl trimethoxysilane is added dropwise, and after continuous stirring, the Ag / Co-MOF@PDA@PU of step (3) is added, and after continuous stirring, the bimetallic MOF photothermal super-hydrophobic polyurethane sponge is obtained by washing with anhydrous ethanol and drying.

3. The bimetallic MOF photothermal superhydrophobic polyurethane sponge of claim 2, wherein: In step (2), the amount of dopamine DA is 0.15 g, and the coating time of dopamine DA is 24 h.

4. The bimetallic MOF photothermal superhydrophobic polyurethane sponge of claim 2, wherein: In step (3), when the bimetallic MOF is grown in situ, the mass ratio of silver nitrate, cobalt nitrate hexahydrate and 2-methylimidazole is 0.4-0.8:0.12-0.36:0.8-1.

82.

5. The bimetallic MOF photothermal superhydrophobic polyurethane sponge of claim 2, wherein: In step (3), when the bimetallic MOF is grown in situ, the temperature of the oil bath is 90℃, and the reaction time is 24 h.

6. The bimetallic MOF photothermal superhydrophobic polyurethane sponge of claim 2, wherein: In step (4), the long-chain alkyl trimethoxysilane is octadecyl trimethoxysilane, dodecyl trimethoxysilane or hexadecyl trimethoxysilane; and the amount of long-chain alkyl trimethoxysilane is 0.5-1.5 mL.

7. The bimetallic MOF photothermal superhydrophobic polyurethane sponge of claim 2, wherein: In step (4), 0.3 mL of acetic acid is dissolved in 30 mL of 95% ethanol solution, and the Ag / Co-MOF@PDA@PU of step (3) is continuously stirred at room temperature for 3 h before and after addition.

8. Use of the bimetallic MOF photothermal superhydrophobic polyurethane sponge according to any one of claims 1-7, characterized in that: The bimetallic MOF photothermal super-hydrophobic polyurethane sponge is used for oil-water separation or micro-plastic absorption treatment.

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