A modified melamine sponge, its preparation method and application

Abstract

This invention provides a modified melamine sponge, its preparation method, and its application, belonging to the field of petroleum resource cleanup and recycling technology. This invention utilizes carbon black as a photothermal conversion material loaded onto melamine sponge, giving the sponge photothermal conversion properties. Polydopamine is used as a binder, which not only effectively strengthens the adhesion between carbon black and the melamine sponge skeleton but also introduces roughness through its own deposition, improving hydrophobicity. Simultaneously, polydopamine also has broadband solar energy absorption characteristics, exhibiting a synergistic effect with carbon black in photothermal conversion. Octadecylamine is used as a superhydrophobic modifying agent to obtain the modified melamine sponge. This modified melamine sponge is superhydrophobic, preventing water absorption while absorbing oil, and also possesses excellent photothermal conversion capabilities, rapidly converting absorbed sunlight into its own heat, thereby heating the contacting heavy oil in situ, reducing the viscosity of the heavy oil, increasing its fluidity, and thus improving the oil absorption rate and capacity.

Description

Technical Field

[0001] This invention belongs to the field of petroleum resource cleanup and recycling technology, specifically relating to a modified melamine sponge, its preparation method, and its application. Background Technology

[0002] With the development of the chemical industry, the demand for offshore crude oil extraction and the transportation of petroleum and chemical solvents has increased. Leaks during the storage and transportation of crude oil and chemicals, as well as illegal industrial discharges, cause significant damage to marine and freshwater resources. Therefore, there is an urgent need for efficient crude oil spill treatment and recovery technologies. However, the global average seawater temperature is approximately 20°C, making the separation and reabsorption of crude oil extremely difficult. Superhydrophobic and superoleophilic sponges with selective absorption properties show great promise for oil-water separation and the adsorption of oil sludge on water surfaces. However, this superhydrophobic and superoleophilic sponge still has poor absorption effect, and can only absorb about 50 times its own weight of oil or organic solvent. For example, CN110003519A describes a method for preparing a superhydrophobic sponge with photothermal effect and magnetic drive flame retardant, including the following steps: Step (1) Pre-treatment of melamine sponge: Immerse the melamine sponge in deionized water, clean it with ultrasound, take it out and dry it, then immerse it in an organic solvent for ultrasonic cleaning, and dry it to obtain the pre-treated melamine sponge; Step (2) Preparation of nanomagnetic particles and PDMS treatment solution: Add PDMS prepolymer to an organic solvent and stir it with magnetic force, then add a curing agent and stir to disperse it evenly; then add nanomagnetic particles to PDMS resin solution under mechanical stirring and ultrasonic dispersion, stir and sonicate to obtain nanomagnetic particles and PDMS treatment solution; Step (3) Immerse the pre-treated melamine sponge in the nanomagnetic particles and PDMS treatment solution, sonicate it, squeeze out the excess treatment solution in the melamine sponge, and then vacuum dry the soaked melamine sponge to obtain the superhydrophobic sponge.

[0003] Therefore, how to improve the adsorption performance of sponges has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a modified melamine sponge, its preparation method, and its applications. The modified melamine sponge provided by this invention exhibits excellent selective absorption and high-capacity absorption performance for heavy oil.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] The present invention provides a modified melamine sponge, comprising a melamine sponge and carbon black, polydopamine and octadecylamine loaded on the melamine sponge.

[0007] This invention also provides a method for preparing the modified melamine sponge described above, comprising the following steps:

[0008] (1) Immerse the melamine sponge in the carbon black dispersion and load it once to obtain the carbon black-loaded melamine sponge;

[0009] (2) The carbon black-loaded melamine sponge obtained in step (1) is immersed in a Tris buffer solution containing dopamine hydrochloride to carry out in-situ polymerization to obtain carbon black-loaded and polydopamine-loaded melamine sponge.

[0010] (3) The melamine sponge loaded with carbon black and polydopamine obtained in step (2) is immersed in an organic solution of octadecylamine for secondary loading to obtain modified melamine sponge.

[0011] Preferably, in step (1), the carbon black has a particle size of 20-30 nm and a specific surface area of ​​150-190 m². 2 / g, the volatile matter content of carbon black is 7~8%.

[0012] Preferably, the concentration of the carbon black dispersion in step (1) is 1.5~2.5 g / L.

[0013] Preferably, the loading time in step (1) is 15~30 minutes.

[0014] Preferably, in step (2), the concentration of dopamine hydrochloride in the tris(hydroxymethyl)aminomethane buffer solution containing dopamine hydrochloride is 1.5~2.5 g / L.

[0015] Preferably, the in-situ polymerization time in step (2) is 16~24h.

[0016] Preferably, the concentration of the organic solution of octadecylamine in step (3) is 3.0~4.5wt%.

[0017] Preferably, the time for the secondary load in step (3) is 25~40 minutes.

[0018] The present invention also provides the application of the modified melamine sponge described in the above technical solution or the modified melamine sponge prepared by the preparation method described in the above technical solution in the absorption of heavy oil.

[0019] This invention provides a modified melamine sponge, comprising a melamine sponge and carbon black, polydopamine, and octadecylamine loaded onto the melamine sponge. This invention utilizes carbon black as a photothermal conversion material loaded onto the melamine sponge, giving the melamine sponge photothermal conversion properties. Polydopamine is used as a binder, which not only effectively strengthens the adhesion between the carbon black and the melamine sponge skeleton but also introduces roughness due to its own deposition, improving hydrophobicity. Simultaneously, polydopamine also has broadband solar energy absorption characteristics, exhibiting a synergistic effect with carbon black in photothermal conversion. Furthermore, polydopamine contains amine functional groups and numerous cyclic indole structures, increasing the variety and number of functional groups on the melamine sponge and improving the loading of octadecylamine. Octadecylamine is used as a superhydrophobic modifying agent to obtain the modified melamine sponge. This modified melamine sponge exhibits superhydrophobicity, preventing water absorption while absorbing oil, and also possesses excellent photothermal conversion capabilities, rapidly converting absorbed sunlight into its own heat, thereby heating the contacting heavy oil in situ, reducing the viscosity of the heavy oil, increasing its fluidity, and thus improving the oil absorption rate and capacity. Experimental results show that the modified melamine sponge provided by this invention has a water contact angle of 153.2 ± 0.6° at 1.0 kW / m². 2 Under simulated sunlight irradiation, the surface temperature of the modified melamine sponge can reach 76.2℃ within 1 minute, demonstrating highly efficient photothermal conversion performance. The oil absorption capacity of heavy and extra-heavy oils (3671~44204 mPa·s) can reach 114~126 times its own weight. After 10 cycles of oil absorption, the absorption capacity still remains above 100 times its own weight. The modified melamine sponge exhibits excellent absorption and circulation performance in absorbing heavy and extra-heavy oils. Attached Figure Description

[0020] Figure 1 This is a process flow diagram for preparing the modified melamine sponge according to the present invention;

[0021] Figure 2 The water contact angle of the clean melamine sponge in Example 1;

[0022] Figure 3 The water contact angle of the modified melamine sponge prepared in Example 1;

[0023] Figure 4 The water contact angle of the modified melamine sponge prepared in Example 2;

[0024] Figure 5 The water contact angle of the modified melamine sponge prepared in Example 3;

[0025] Figure 6 The water contact angle of the modified melamine sponge prepared in Comparative Example 4;

[0026] Figure 7The water contact angle of the modified melamine sponge prepared in Example 4;

[0027] Figure 8 The water contact angle of the modified melamine sponge prepared in Comparative Example 5;

[0028] Figure 9 The graph shows the temperature variations of the upper and lower surfaces of the modified melamine sponge prepared in Example 1 with different light intensities.

[0029] Figure 10 The graph shows the temperature change of the upper surface of the modified melamine sponge under different light intensities over time.

[0030] Figure 11 The modified melamine sponge prepared in Example 1 has an oil absorption capacity of 10 times when it adsorbs crude oil A.

[0031] Figure 12 The modified melamine sponge prepared in Example 1 has an oil absorption capacity of 10 times when it adsorbs crude oil B.

[0032] Figure 13 The modified melamine sponge prepared in Example 1 has an oil absorption capacity of 10 times when it adsorbs crude oil C.

[0033] Figure 14 The image shows the modified melamine sponge prepared in Example 1 after ten cycles of adsorbing crude oil A, followed by cleaning and drying, and its water contact angle.

[0034] Figure 15 The image shows the modified melamine sponge prepared in Example 1 after ten cycles of adsorbing crude oil B, followed by cleaning and drying, and its water contact angle.

[0035] Figure 16 The image shows the modified melamine sponge prepared in Example 1 after ten cycles of adsorbing crude oil C, followed by cleaning and drying, and its water contact angle.

[0036] Figure 17 The process of the modified melamine sponge prepared in Example 1 absorbing heavy oil from water. Detailed Implementation

[0037] The present invention provides a modified melamine sponge, comprising a melamine sponge and carbon black, polydopamine and octadecylamine loaded on the melamine sponge.

[0038] In this invention, the water contact angle of the modified melamine sponge is preferably ≥150°; the modified melamine sponge has a water contact angle of 1.0 kW / m 2 Under sunlight irradiation, the surface temperature should preferably rise to above 76°C within 1 minute; for a viscosity of 3×10 3 ~4.5×10 4For heavy and extra-heavy oils at mPa·s, the absorption capacity of the modified melamine sponge is preferably 114 to 126 times its own weight.

[0039] This invention utilizes carbon black as a photothermal conversion material loaded onto melamine sponge, giving the melamine sponge photothermal conversion properties. Polydopamine is used as a binder, which not only effectively strengthens the adhesion between carbon black and the melamine sponge skeleton but also introduces roughness through its own deposition, improving hydrophobicity. Simultaneously, polydopamine also possesses broadband solar energy absorption characteristics, exhibiting a synergistic effect with carbon black in photothermal conversion. Furthermore, polydopamine contains amine functional groups and numerous cyclic indole structures, increasing the variety and number of functional groups on the melamine sponge and enhancing the loading of octadecylamine. Octadecylamine is used as a superhydrophobic modifier to obtain a modified melamine sponge. This modified melamine sponge exhibits superhydrophobicity, preventing water absorption while absorbing oil, and also possesses excellent photothermal conversion capabilities, rapidly converting absorbed sunlight into its own heat, thereby heating the contacting heavy oil in situ, reducing the viscosity of the heavy oil, increasing its fluidity, and thus improving the oil absorption rate and capacity.

[0040] The modified melamine sponge provided by this invention can rapidly heat itself up through solar heat, thereby heating crude oil in situ, absorbing crude oil quickly and in large capacity, and after absorbing oil, the absorbed oil can be squeezed out and recycled.

[0041] This invention also provides a method for preparing the modified melamine sponge described above, comprising the following steps:

[0042] (1) Immerse the melamine sponge in the carbon black dispersion and load it once to obtain the carbon black-loaded melamine sponge;

[0043] (2) The carbon black-loaded melamine sponge obtained in step (1) is immersed in a tris(hydroxymethyl)aminomethane buffer solution containing dopamine hydrochloride and polymerized in situ to obtain carbon black-loaded and polydopamine-loaded melamine sponge.

[0044] (3) The melamine sponge loaded with carbon black and polydopamine obtained in step (2) is immersed in an organic solution of octadecylamine for secondary loading to obtain modified melamine sponge.

[0045] Unless otherwise specified, all raw materials used in this invention are commercially available products well known in the art.

[0046] This invention involves immersing a melamine sponge in a carbon black dispersion and subjecting it to a single loading process to obtain a carbon black-loaded melamine sponge.

[0047] In this invention, the porosity of the melamine sponge is preferably 95-99%, more preferably 99%; the density of the melamine sponge is preferably 9.0-9.8 kg / m³. 3More preferably 9.5 kg / m 3 .

[0048] In this invention, the melamine sponge is preferably cut, cleaned and dried sequentially before use.

[0049] The present invention does not impose any special limitations on the cutting operation; any operation known to those skilled in the art can be used to cut to the required size.

[0050] In this invention, the cleaning process preferably includes: ultrasonically cleaning the melamine sponge sequentially with anhydrous ethanol and ultrapure water; the ultrasonic cleaning time is preferably 15-30 minutes, more preferably 20 minutes. This invention effectively removes dirt from the melamine sponge.

[0051] In this invention, the drying temperature is preferably 50~80℃, more preferably 60℃; the drying time is preferably 8~24h, more preferably 8h.

[0052] In this invention, the carbon black dispersion is preferably obtained by ultrasonication of carbon black and ultrapure water. This invention does not impose any particular limitations on the operation of preparing the carbon black dispersion by ultrasonication of carbon black and ultrapure water, as long as a carbon black dispersion is obtained.

[0053] In this invention, the particle size of the carbon black is preferably 20-30 nm; the specific surface area of ​​the carbon black is preferably 150-190 m². 2 / g; the volatile matter content of the carbon black is preferably 7~8%.

[0054] In this invention, the concentration of the carbon black dispersion is preferably 1.5~2.5 g / L, more preferably 2.0 g / L. Limiting the concentration of the carbon black dispersion within the above range improves the modification effect on melamine sponges.

[0055] The present invention does not have special requirements on the amount of melamine sponge and carbon black dispersion, as long as the melamine sponge is completely submerged.

[0056] The present invention does not have any special limitations on the operation of immersing the melamine sponge in the carbon black dispersion; any operation known to those skilled in the art can be used.

[0057] In this invention, the primary loading is preferably performed under ultrasonic conditions. This invention does not have special requirements for the ultrasonic power; any ultrasonic power well-known in the art can be used. This invention utilizes ultrasound to fully disperse and load carbon black onto the melamine sponge; during the ultrasonic immersion of the melamine sponge in the carbon black dispersion, a large number of carbon black nanoparticles are loaded onto the surface of the melamine sponge, thereby improving the photothermal conversion performance of the melamine sponge.

[0058] In this invention, the duration of the single load is preferably 15-30 minutes, more preferably 20 minutes. This invention does not impose any special limitations on the temperature of the single load; it can be performed at room temperature.

[0059] After one loading is completed, the present invention preferably removes the product obtained from the carbon black dispersion and then dries it to obtain a carbon black-loaded melamine sponge.

[0060] The present invention does not impose any special limitations on the operation of removing carbon black from the dispersion; any operation known to those skilled in the art can be used.

[0061] In this invention, the drying temperature is preferably 50~80℃, more preferably 60℃; the drying time is preferably 8~24h, more preferably 8h.

[0062] After obtaining the carbon black-loaded melamine sponge, this invention immerses the carbon black-loaded melamine sponge in a tris(hydroxymethyl)aminomethane buffer solution containing dopamine hydrochloride for in-situ polymerization, yielding a melamine sponge loaded with carbon black and polydopamine. This invention utilizes polydopamine, formed by the self-polymerization of dopamine, as a binder. This not only effectively strengthens the adhesion between the carbon black and the sponge skeleton but also introduces roughness due to its own deposition, improving hydrophobicity. Polydopamine also possesses broadband solar energy absorption characteristics, exhibiting a synergistic effect with carbon black in photothermal conversion. Simultaneously, polydopamine contains amine functional groups and numerous cyclized indole structures, increasing the variety and number of functional groups on the melamine sponge, facilitating subsequent grafting of octadecylamine.

[0063] In this invention, the Tris buffer solution containing dopamine hydrochloride is preferably obtained by mixing dopamine hydrochloride, Tris and ultrapure water.

[0064] In this invention, the concentration of dopamine hydrochloride in the Tris buffer solution containing dopamine hydrochloride is preferably 1.5~2.5 g / L, more preferably 2.0 g / L; the pH of the Tris buffer solution containing dopamine hydrochloride is preferably 8.3~8.7, more preferably 8.5; and the concentration of Tris in the Tris buffer solution containing dopamine hydrochloride is preferably 50 mM.

[0065] In this invention, the Tris buffer solution containing dopamine hydrochloride is preferably adjusted for pH using dilute hydrochloric acid.

[0066] In this invention, the volume ratio of the Tris buffer solution containing dopamine hydrochloride to the melamine sponge loaded with carbon black is preferably ≥5. By limiting the above volume ratio, this invention ensures that the surface of the melamine sponge skeleton can be fully coated after the dopamine self-polymerizes into polydopamine.

[0067] The present invention does not have any particular limitations on the operation of immersing the carbon black-loaded melamine sponge in a tris(hydroxymethyl)aminomethane buffer solution containing dopamine hydrochloride; any operation known to those skilled in the art can be used.

[0068] In this invention, the in-situ polymerization time is preferably 16-24 hours, more preferably 18-20 hours; the in-situ polymerization is preferably carried out under stirring conditions; the stirring rate is preferably 400-500 rpm.

[0069] After the in-situ polymerization is completed, the present invention preferably removes the product obtained by the in-situ polymerization from the Tris buffer solution containing dopamine hydrochloride, and then washes and dries it in sequence to obtain a melamine sponge loaded with carbon black and polydopamine.

[0070] The present invention does not have any particular limitations on the operation of removing the sample from the Tris buffer solution containing dopamine hydrochloride; any operation known to those skilled in the art can be used.

[0071] In this invention, the washing solution used is preferably ultrapure water. This invention does not impose any special limitations on other washing operations, as long as the ultrapure water becomes clear.

[0072] In this invention, the drying temperature is preferably 50~80℃, more preferably 60℃; the drying time is preferably 8~24h, more preferably 8h.

[0073] After obtaining the melamine sponge loaded with carbon black and polydopamine, this invention further impregnates the melamine sponge with carbon black and polydopamine in an organic solution of octadecylamine for secondary loading, thereby obtaining a modified melamine sponge. This invention utilizes octadecylamine as a superhydrophobic modifier grafted onto the melamine sponge, giving the melamine sponge superhydrophobicity, enabling it to absorb oil while preventing water absorption, thus improving oil absorption rate and oil absorption capacity.

[0074] In this invention, the solvent for the organic solution of octadecylamine is preferably anhydrous ethanol; the concentration of the organic solution of octadecylamine is preferably 3.0~4.5 wt%, more preferably 3.5 wt%. In this invention, anhydrous ethanol is inexpensive and has low pollution levels, and will not inhibit the reaction process during the subsequent modification of melamine sponge.

[0075] The present invention does not impose any special limitations on the preparation method of the organic solution of the octadecylamine; any operation known to those skilled in the art can be used.

[0076] In an embodiment of the present invention, the organic solution of octadecylamine is prepared by mixing anhydrous ethanol with octadecylamine, heating in a water bath to 60°C, and then cooling to room temperature.

[0077] The present invention does not have any particular limitations on the operation of immersing the melamine sponge loaded with carbon black and polydopamine into an organic solution of octadecylamine; any operation known to those skilled in the art can be used.

[0078] In this invention, the secondary loading time is preferably 25-40 minutes, more preferably 30 minutes. This invention does not impose any special limitations on the temperature of the secondary loading; it can be performed at room temperature.

[0079] After the secondary loading is completed, the product obtained by the secondary loading is preferably taken out of the solution and then subjected to a first drying, washing and a second drying in sequence to obtain the modified melamine sponge.

[0080] The present invention does not impose any special limitations on the operation of removing the contents from the solution; any operation known to those skilled in the art can be used.

[0081] In this invention, the temperature of the primary drying step is preferably 25~60℃, more preferably 60℃; the drying time is preferably 8~24h, more preferably 8h. This invention utilizes a primary drying step to ensure that octadecylamine is more evenly and firmly loaded onto the sponge.

[0082] In this invention, the detergent used for washing is preferably anhydrous ethanol. This invention does not impose any special limitations on the washing operation; any operation well-known to those skilled in the art can be used.

[0083] In this invention, the temperature of the secondary drying is preferably 25~60℃, more preferably 60℃; the time of the secondary drying is preferably 8~24h, more preferably 8h.

[0084] The preparation method provided by this invention is simple to operate.

[0085] The process flow diagram for preparing modified melamine sponge according to this invention is as follows: Figure 1 As shown.

[0086] from Figure 1 As can be seen, firstly, the melamine sponge is immersed in a carbon black dispersion and sonicated, then removed and dried to obtain a carbon black-loaded melamine sponge; then, the carbon black-loaded melamine sponge is immersed in a Tris buffer solution containing dopamine hydrochloride, stirred, removed and dried to obtain a carbon black and polydopamine-loaded melamine sponge; finally, the carbon black and polydopamine-loaded melamine sponge is immersed in an anhydrous ethanol solution of octadecylamine for modification, removed and dried to obtain a modified melamine sponge.

[0087] The present invention also provides the application of the modified melamine sponge described in the above technical solution or the modified melamine sponge prepared by the preparation method described in the above technical solution in the absorption of heavy oil.

[0088] The present invention does not impose any special limitations on the operation of the modified melamine sponge in absorbing heavy oil; any operation familiar to those skilled in the art can be used.

[0089] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0090] Example 1

[0091] The modified melamine sponge consists of melamine sponge and carbon black, polydopamine, and octadecylamine loaded on the melamine sponge;

[0092] The preparation method of the modified melamine sponge consists of the following steps:

[0093] (1) The melamine sponge was cut into cubes of 2cm×2cm×2cm, and then ultrasonically cleaned with anhydrous ethanol and ultrapure water for 20min each, and then dried in an oven at 60℃ for 8h to obtain clean melamine sponge; wherein the porosity of the melamine sponge was 99% and the density was 9.5kg / m³. 3 ;

[0094] (2) Add 0.2g of carbon black to 100mL of ultrapure water and sonicate for 20min to obtain a carbon black dispersion with a concentration of 2.0g / L. Immerse the clean melamine sponge obtained in step (1) into the carbon black dispersion and sonicate for 20min for loading. After removal, place it directly in a 60℃ oven and dry for 8h to obtain a melamine sponge loaded with carbon black. The carbon black has a particle size of 20~30nm and a specific surface area of ​​150~190m². 2 / g, volatile matter 7~8%;

[0095] (3) Dilute concentrated hydrochloric acid to 1M, then dissolve 1g of dopamine hydrochloride in 500mL of ultrapure water, add 50mM of Tris, stir to dissolve, measure the pH of the prepared solution with a pH meter, add 1M hydrochloric acid dropwise to the prepared solution until the pH of the solution is 8.5, and obtain a Tris buffer solution containing dopamine hydrochloride; wherein, the concentration of dopamine hydrochloride in the Tris buffer solution containing dopamine hydrochloride is 2.0g / L;

[0096] (4) The carbon black-loaded melamine sponge obtained in step (2) is immersed in the Tris buffer solution containing dopamine hydrochloride obtained in step (3), and stirred at 500 rpm for 24 h for in-situ polymerization. Then it is taken out, washed with ultrapure water until the water is clear, and then placed in a 60℃ oven to dry for 8 h to obtain carbon black-loaded melamine sponge and polydopamine; wherein the volume ratio of the Tris buffer solution containing dopamine hydrochloride to the carbon black-loaded melamine sponge is 5.

[0097] (5) Add 96.5g of anhydrous ethanol to a beaker, add 3.5g of octadecylamine to the beaker, heat in a water bath to 60°C, and then cool the solution to room temperature to obtain an anhydrous ethanol solution of octadecylamine with a concentration of 3.5wt%. Then immerse the melamine sponge loaded with carbon black and polydopamine obtained in step (4) into the anhydrous ethanol solution of octadecylamine, let it stand for 30min for secondary loading, then take it out and dry it in a 60°C oven for 8h to obtain a sponge wrapped with a white shell of octadecylamine. Then put this sponge into anhydrous ethanol until the white shell is completely dissolved. Finally, dry it in a 60°C oven for 8h to obtain a modified melamine sponge, denoted as OPCM.

[0098] Example 2

[0099] Based on Example 1, the concentration of the anhydrous ethanol solution of octadecylamine was changed to 3.0 wt%, while other conditions remained unchanged.

[0100] Example 3

[0101] Based on Example 1, the concentration of the anhydrous ethanol solution of octadecylamine was changed to 4.0 wt%, while other conditions remained unchanged.

[0102] Example 4

[0103] Based on Example 1, the time for the secondary load was changed to 40 minutes, while other conditions remained unchanged.

[0104] Comparative Example 1

[0105] The method for preparing carbon black-loaded melamine sponge is as follows: based on Example 1, the concentration of the carbon black dispersion is changed to 1.5 g / L, while other conditions remain unchanged.

[0106] Comparative Example 2

[0107] The method for preparing carbon black-loaded melamine sponge is as follows: based on Example 1, the concentration of the carbon black dispersion is changed to 2.5 g / L, while other conditions remain unchanged.

[0108] Comparative Example 3

[0109] The method for preparing carbon black-loaded melamine sponge is as follows: based on Example 1, the concentration of the carbon black dispersion is changed to 1.0 g / L, while other conditions remain unchanged.

[0110] Comparative Example 4

[0111] Based on Example 1, the concentration of the anhydrous ethanol solution of octadecylamine was changed to 2.5 wt%, while other conditions remained unchanged.

[0112] Comparative Example 5

[0113] Based on Example 1, the time for the secondary load was changed to 20 minutes, while other conditions remained unchanged.

[0114] Structural and performance characterization:

[0115] 1. The photothermal temperature of the carbon black-loaded melamine sponges in Example 1 and Comparative Examples 1-3 was measured. The photothermal temperature was measured using a xenon lamp simulating 1kW / m². 2 The surface temperature of melamine sponge (CM) loaded with carbon black was measured using an infrared thermal imager under sunlight irradiation. The results are shown in Table 1.

[0116] Table 1. Surface temperatures of carbon black-loaded melamine sponges in Example 1 and Comparative Examples 1-3

[0117]

[0118] As shown in Table 1, the photothermal temperature of CM increases with the increase of carbon black dispersion concentration; when the carbon black dispersion concentration is 1.0 g / L, the surface temperature of CM only reaches 66.7℃; while when the carbon black dispersion concentration is 2.0 g / L and 2.5 g / L, the surface temperature of CM can reach about 75℃.

[0119] 2. Water contact angle tests were performed on the clean melamine sponge from Example 1, the modified melamine sponges prepared in Examples 1-3, and Comparative Example 4. The tests were conducted using a Teclis Tracker interfacial tensiometer (manufactured by a French company). The melamine sponge and the modified melamine sponge were placed flat on the instrument platform. Using the syringe provided with the instrument, 5 μL of deionized water was added to the surface of the sponge each time using the pendant drop method. The water contact angle was calculated using the sessile drop young-Laplace software. Measurements were repeated at five different locations on each sample, and the mean and standard deviation were calculated. The results are as follows: Figures 2-6 As shown in Table 2, Figure 2 The water contact angle of the clean melamine sponge in Example 1; Figure 3 The water contact angle of the modified melamine sponge prepared in Example 1; Figure 4 The water contact angle of the modified melamine sponge prepared in Example 2; Figure 5 The water contact angle of the modified melamine sponge prepared in Example 3; Figure 6 The water contact angle is shown for the modified melamine sponge prepared in Comparative Example 4.

[0120] Table 2. Water contact angles of the clean melamine sponge in Example 1, the modified melamine sponges prepared in Examples 1-3, and Comparative Example 4.

[0121]

[0122] Depend on Figures 2-6 As shown in Table 2, the hydrophobicity of the modified melamine sponge increases with the increase of the concentration of the anhydrous ethanol solution of octadecylamine. When the concentration of the anhydrous ethanol solution of octadecylamine is 2.5 wt%, the water contact angle of the modified melamine sponge is <150°. When the concentration of octadecylamine is 3.5 wt% and 4.0 wt%, the water contact angle of the modified melamine sponge is >153°, which shows superhydrophobicity. The stronger the hydrophobicity, the higher the oil-water separation efficiency.

[0123] 3. The modified melamine sponges prepared in Example 4 and Comparative Example 5 were tested for water contact angle according to the above method. The results are as follows: Figures 7-8 As shown in Table 3, Figure 7 The water contact angle of the modified melamine sponge prepared in Example 4; Figure 8 The water contact angle is shown in Comparative Example 5 for the modified melamine sponge.

[0124] Table 3. Water contact angles of the clean melamine sponge in Example 1, and the modified melamine sponges prepared in Examples 1, 4, and Comparative Example 5.

[0125]

[0126] Depend on Figure 2 , 3 As can be seen from Tables 7-8 and 3, the water contact angle of the modified melamine sponge reaches its maximum when the secondary load time is 30 min.

[0127] 4. The photothermal conversion temperature of the modified melamine sponge OPCM prepared in Example 1 was tested: a xenon lamp was used as the light source to simulate sunlight, and the light intensity of the xenon lamp source was set to 0.5 kW / m². 2 1.0kW / m 2 1.5kW / m 2 2.0kW / m 2 2.5kW / m 2 The modified melamine sponge was irradiated for 6 minutes each time, with one cycle lasting 10 minutes. This cycle, from the moment the OPCM light source was turned on to the point where the temperature dropped to room temperature after the light source was turned off, took 10 minutes. The surface temperature of the modified melamine sponge was recorded over time using an infrared thermal imager. The results are as follows: Figure 9 and 10 As shown, Figure 9The graph shows the temperature variations of the upper and lower surfaces of the modified melamine sponge prepared in Example 1 with different light intensities. Figure 10 The graph shows the temperature change of the upper surface of the modified melamine sponge under different light intensities over time.

[0128] Depend on Figure 9 and 10 It can be seen that as the light intensity increases from 0.5 kW / m², 2 Up to 2.5kW / m 2 The surface temperature of the modified melamine sponge increased from 46.5℃ to 117.2℃; when the light intensity was 1.0 kW / m²... 2 At this point, the surface temperature of the modified melamine sponge reaches 76.2℃. Clearly, the steady-state temperature at the top of the modified melamine sponge is positively correlated with the light power, and a similar relationship exists at the bottom. Under different light intensities, the surface temperature of the modified melamine sponge rises rapidly and stabilizes within 1 minute, indicating that the modified melamine sponge can rapidly convert absorbed light into heat and transfer it to the bottom of the sponge. Therefore, the rapid heating and thermal conductivity of the modified melamine sponge surface can reduce the viscosity of heavy oil, increase its fluidity, and thus improve its oil absorption efficiency.

[0129] 5. The heavy oil absorption performance of the modified melamine sponges prepared in Examples 1-4 was tested: Three types of heavy oil and extra-heavy oil with different viscosities were selected (at room temperature of 20°C, the viscosities were crude oil A: 44204 mPa·s, crude oil B: 9373 mPa·s, and crude oil C: 3671 mPa·s, respectively). The dry weight of the modified melamine sponge that had not absorbed heavy oil was weighed and recorded. Then, at 1kW / m 2 Under simulated sunlight, modified melamine sponges were immersed in heavy oil for 40 minutes. They were then gently removed with tweezers, and the mass of the modified melamine sponge after absorbing heavy oil was measured when no excess oil dripped down. The absorption capacity of the modified melamine sponge for heavy oil (Q) is then determined. W The result (g / g) is calculated using the following formula:

[0130]

[0131] Where m0 is the dry weight of the modified melamine sponge that has not absorbed heavy oil, and m1 is the mass of the modified melamine sponge that has absorbed heavy oil.

[0132] According to the formula, the calculation is as follows:

[0133] The modified melamine sponge prepared in Example 1 had a maximum saturated absorption capacity of 126 g / g for crude oil A, 117 g / g for crude oil B, and 114 g / g for crude oil C. Under no light conditions, the modified melamine sponge was difficult to immerse in heavy oil. It took 43 minutes for the modified melamine sponge to be immersed in crude oil C; and 1 hour for it to be immersed in crude oil B by approximately 1 cm. The modified melamine sponge remained on the surface of crude oil A. At 1 kW / m³... 2 Under simulated sunlight irradiation, the complete immersion times of the modified melamine sponge on the surfaces of crude oils A, B, and C were approximately 33 min, 10 min, and 6.5 min, respectively, showing a significant increase in immersion rate. This indicates that the solar photothermal conversion plays a crucial role in the oil absorption of the modified sponge. The excellent photothermal conversion performance of the modified melamine sponge allows it to heat the heavy oil upon heating, reducing its viscosity and increasing its fluidity. Furthermore, the hydrophobic and capillary forces of the modified melamine sponge accelerate its absorption rate of crude oil; its oil absorption capacity increases to more than 114 times its own weight.

[0134] The modified melamine sponge prepared in Example 2 has a maximum saturated absorption capacity of 124 g / g for crude oil A, 116 g / g for crude oil B, and 114 g / g for crude oil C.

[0135] The modified melamine sponge prepared in Example 3 has a maximum saturated absorption capacity of 127 g / g for crude oil A, 117 g / g for crude oil B, and 114 g / g for crude oil C.

[0136] The modified melamine sponge prepared in Example 4 has a maximum saturated absorption capacity of 125 g / g for crude oil A, 117 g / g for crude oil B, and 113 g / g for crude oil C.

[0137] 6. The cyclic oil absorption performance of the modified melamine sponge prepared in Example 1 was tested: The oil absorption method described in 5 above allowed the modified melamine sponge to absorb heavy oil. After each oil absorption, the absorbed oil was released by squeezing. The heavy oil absorption capacity of the modified melamine sponge was calculated according to the formula in 5. Each oil absorption cycle was recorded as one complete oil absorption cycle. Then, the squeezed sponge was immersed in 40 mL of cyclohexane three times, each time for 5 minutes. After immersion, the sponge was removed, the absorbed cyclohexane was released by squeezing, and then it was dried in a 60℃ oven for 3.5 hours before being used again to absorb heavy oil. The results are as follows: Figures 11-16 As shown, Figure 11 The modified melamine sponge prepared in Example 1 has an oil absorption capacity of 10 times when it adsorbs crude oil A. Figure 12 The modified melamine sponge prepared in Example 1 has an oil absorption capacity of 10 times when it adsorbs crude oil B. Figure 13 The modified melamine sponge prepared in Example 1 has an oil absorption capacity of 10 times when it adsorbs crude oil C. Figure 14The image shows the modified melamine sponge prepared in Example 1 after ten cycles of adsorbing crude oil A, followed by cleaning and drying, and its water contact angle. Figure 15 The image shows the modified melamine sponge prepared in Example 1 after ten cycles of adsorbing crude oil B, followed by cleaning and drying, and its water contact angle. Figure 16 The image shows the modified melamine sponge prepared in Example 1 after ten cycles of adsorbing crude oil C, followed by cleaning and drying, and its water contact angle.

[0138] Depend on Figures 11-16 It can be seen that after 10 cycles, the absorption capacity of the modified melamine sponge still remains more than 100 times its own weight, showing excellent high absorption capacity; moreover, the modified melamine sponge is not damaged, showing good rigidity and toughness; at the same time, the modified melamine sponge still has excellent hydrophobic properties, with water contact angles of 142.2°, 147.5° and 144.7°, all above 140°. Its excellent performance in cyclic oil absorption is due to its robust hydrophobic modification, stable mechanical properties and excellent photothermal properties.

[0139] 7. An oil absorption experiment was conducted on the modified melamine sponge prepared in Example 1: At 20°C, 1g of heavy oil was dropped onto a petri dish containing tap water, and gently stirred with a magnetic stirrer to disperse the oil droplets, simulating the dispersion and floating of heavy oil from a marine oil spill. A xenon lamp was used as the light source to simulate sunlight, and the light intensity of the xenon lamp was set to 1.0 kW / m². 2 To simulate sunlight, a modified melamine sponge was placed on the water surface. The modified melamine sponge floated on the water and quickly absorbed the viscous oil on the surface. This is because the superhydrophobicity of the modified melamine sponge allows it to float on the water surface, and it absorbs oil without absorbing water. Under simulated sunlight, the modified melamine sponge transfers the absorbed heat to the bottom, heating the viscous oil on the surface, reducing the viscosity of the viscous oil, and accelerating the absorption rate of the viscous oil.

[0140] Figure 17 This describes the process by which the modified melamine sponge prepared in Example 1 absorbs heavy oil on water. In the absence of light, the modified melamine sponge can hardly absorb any heavy oil. Regardless of whether there is light, the unmodified original melamine sponge cannot quickly absorb heavy oil and, due to its lack of superhydrophobicity, quickly sinks to the bottom and becomes saturated with water.

[0141] In summary, using the method provided by this invention, the modified melamine sponge prepared in Example 1 has a water contact angle of 153.2 ± 0.6°, indicating a superhydrophobic state; at 1.0 kW / m 2Under simulated sunlight irradiation, the surface temperature of the modified melamine sponge can reach 76.2℃ within 1 minute, demonstrating highly efficient photothermal conversion performance. Therefore, the modified melamine sponge can rapidly heat heavy oil under light irradiation, increasing its fluidity and thus improving oil absorption efficiency. The modified melamine sponge can absorb 114 to 126 times its own weight in heavy and extra-heavy oils with viscosities ranging from 3671 to 44204 mPa·s. After 10 cycles of oil absorption, the absorption capacity remains above 100 times its own weight, demonstrating excellent absorption and circulation performance in absorbing heavy and extra-heavy oils.

[0142] As can be seen from the above embodiments and comparative examples, the modified melamine sponge provided by the present invention has excellent selective adsorption performance of heavy oil.

[0143] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A modified melamine sponge, characterized in that, Includes melamine sponge and carbon black, polydopamine, and octadecylamine loaded on the melamine sponge; The preparation method of the modified melamine sponge includes the following steps: (1) Immerse the melamine sponge in the carbon black dispersion and load it once to obtain the carbon black-loaded melamine sponge; (2) The carbon black-loaded melamine sponge obtained in step (1) is immersed in a tris(hydroxymethyl)aminomethane buffer solution containing dopamine hydrochloride and polymerized in situ to obtain carbon black-loaded and polydopamine-loaded melamine sponge. (3) The melamine sponge loaded with carbon black and polydopamine obtained in step (2) is immersed in an organic solution of octadecylamine for secondary loading to obtain a modified melamine sponge. The time for the secondary load in step (3) is 30 minutes.

2. The method for preparing the modified melamine sponge according to claim 1, characterized in that, Includes the following steps: (1) Immerse the melamine sponge in the carbon black dispersion and load it once to obtain the carbon black-loaded melamine sponge; (2) The carbon black-loaded melamine sponge obtained in step (1) is immersed in a tris(hydroxymethyl)aminomethane buffer solution containing dopamine hydrochloride and polymerized in situ to obtain carbon black-loaded and polydopamine-loaded melamine sponge. (3) The melamine sponge loaded with carbon black and polydopamine obtained in step (2) is immersed in an organic solution of octadecylamine for secondary loading to obtain a modified melamine sponge. The time for the secondary load in step (3) is 30 minutes.

3. The preparation method according to claim 2, characterized in that, In step (1), the carbon black has a particle size of 20-30 nm and a specific surface area of ​​150-190 m². 2 / g, the volatile matter content of carbon black is 7~8%.

4. The preparation method according to claim 2, characterized in that, The concentration of the carbon black dispersion in step (1) is 1.5~2.5 g / L.

5. The preparation method according to claim 2, characterized in that, The duration of one load in step (1) is 15-30 minutes.

6. The preparation method according to claim 2, characterized in that, In step (2), the concentration of dopamine hydrochloride in the tris(hydroxymethyl)aminomethane buffer solution containing dopamine hydrochloride is 1.5~2.5 g / L.

7. The preparation method according to claim 2, characterized in that, The in-situ polymerization time in step (2) is 16~24h.

8. The preparation method according to claim 2, characterized in that, The concentration of the organic solution of octadecylamine in step (3) is 3.0~4.5wt%.

9. The application of the modified melamine sponge according to claim 1 or the modified melamine sponge prepared by any one of claims 2 to 8 in the absorption of heavy oil.

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