Super-hydrophobic melamine porous material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of modification of melamine porous materials, in particular to a super-hydrophobic melamine porous material as well as a preparation method and application thereof. The melamine porous material contains hydrophobic groups; the hydrophobic group comprises carbonyl. The super-hydrophobic melamine porous material disclosed by the invention is large in saturation adsorption capacity on oil gas and high in long-period adsorption efficiency.

Description

Technical Field

[0001] This invention relates to the field of melamine porous material modification technology, specifically to a superhydrophobic melamine porous material, its preparation method, and its application. Background Technology

[0002] Melamine porous materials (also known as melamine-formaldehyde porous materials) have long been a commonly used matrix material for developing hydrophobic adsorption materials due to their permeable porous structure, excellent mechanical properties, and abundant chemical modification sites. However, because melamine porous materials contain a large number of hydrophilic groups on their surface, their interaction with oils and gases is weak, thus requiring hydrophobic modification. CN114561039A, CN113980347A, and CN111892741A disclose methods for modifying hydrophobic melamine porous materials. However, the high cost of the hydrophobic modifiers, the complexity of the hydrophobic modification process, and the environmentally unfriendly nature of the modifying solvents limit the further industrial production and application of hydrophobic melamine porous materials.

[0003] Liu Shuaizhuo et al. disclosed a simple method for superhydrophobic modification of melamine porous materials in CN110628076A and melamine sponge and its application in oil-water separation [J]. Journal of Chemical Research of Chinese Universities, 2020, 41(3):9. The method involves modifying melamine porous materials by soaking in nitric acid solution and drying, followed by grafting nitro groups onto the melamine porous materials to obtain superhydrophobic melamine porous materials. Compared to unmodified melamine porous materials, the superhydrophobic melamine porous materials exhibit significant condensation and expansion of the framework, resulting in poor recyclability. Specifically, the adsorption efficiency of the obtained superhydrophobic melamine porous materials for oil and gas decreases with increasing usage time, especially after high-temperature purging, where the adsorption efficiency drops rapidly.

[0004] Currently, hydrophobic melamine porous materials are mostly used in oil-water separation. In recent years, large-flow, continuous oily vapor emissions have been largely integrated into centralized waste gas treatment pipelines. However, some oil and gas emission sites still cannot be centrally treated due to their large flow variations and large number. For these sites, the industry generally uses adsorption equipment with activated carbon as the adsorbent to treat oil and gas. However, activated carbon has significant drawbacks, such as low saturation adsorption capacity, poor long-term adsorption effect, and large solid waste generation. Therefore, there is an urgent need to develop new oil and gas adsorption materials. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of low saturated adsorption capacity and short replacement cycle of existing oil and gas adsorption materials, and to provide a superhydrophobic melamine porous material, its preparation method and application; the superhydrophobic melamine porous material of this invention has a large saturated adsorption capacity for oil and gas and high long-term adsorption efficiency.

[0006] To achieve the above objectives, the first aspect of the present invention provides a superhydrophobic melamine porous material containing hydrophobic groups; the hydrophobic groups include carbonyl groups.

[0007] A second aspect of the present invention provides a method for preparing the superhydrophobic melamine porous material of the present invention, the method comprising:

[0008] The superhydrophobic melamine porous material was obtained by contacting the melamine porous material matrix with an acid solution, followed by microwave irradiation, washing, and drying.

[0009] Contact time is 0.5-100 seconds;

[0010] Microwave irradiation conditions include: irradiation power of 100-2000W; irradiation time of 20s-20min.

[0011] A third aspect of the present invention provides the application of the superhydrophobic melamine porous material described above in oil-gas separation and / or adsorption.

[0012] Through the above technical solution, the hydrophilic groups in the melamine porous material matrix of the present invention undergo rapid hydrolysis reaction under the action of microwave and acidic solution, and partially transform into hydrophobic groups. The surface energy of the melamine porous material decreases rapidly, thereby constructing a superhydrophobic surface.

[0013] This invention regulates the degree of hydrolysis by adjusting microwave power and acid solution concentration. During the modification process, the asymmetric structure of the hydrophilic groups allows for rapid absorption of microwave energy, resulting in a hydrolysis reaction. The superhydrophobic melamine porous material prepared using the method described in this invention possesses superhydrophobic properties while maintaining the original porosity and pore structure of the melamine porous material matrix. Simultaneously, the superhydrophobic melamine porous material retains the high resilience, high porosity, and heat resistance characteristics of the original three-dimensional porous polymer matrix.

[0014] The preparation method of the superhydrophobic melamine porous material described in this invention is simple and rapid, and the modified solvent is cheap and readily available, which has great industrialization prospects and broad potential applications.

[0015] The superhydrophobic melamine porous material described in this invention has high porosity and low density, resulting in a large saturated adsorption capacity for oil and gas and good long-term separation performance. It has significant advantages in applications such as oil and gas adsorption and / or separation.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The preparation method of the superhydrophobic melamine porous material of the present invention is simple, has a short preparation cycle, uses inexpensive and readily available solutions, and is easy to operate continuously, which is conducive to large-scale industrial production.

[0018] 2. The superhydrophobic melamine porous material of the present invention undergoes a hydrophilic-hydrophobic transformation in its structure. The porosity of the material remains basically unchanged compared to the unmodified state, and the material has excellent superhydrophobic properties and temperature resistance.

[0019] 3. The superhydrophobic melamine porous material described in this invention has significant advantages when applied to oil and gas adsorption and separation scenarios, exhibiting a large saturated adsorption capacity for oil and gas and high long-term adsorption efficiency. Attached Figure Description

[0020] Figure 1 These are physical images and scanning electron microscope images of the microstructure of Example 1;

[0021] Figure 2 shows the infrared spectra of the melamine porous material matrix, Example 1, Example 9, and Example 10. Figure 2-B , Figure 2-C for Figure 2-A (A magnified view of a portion of the image);

[0022] Figure 3 These are thermogravimetric curves of the unmodified melamine porous material, Example 1, and Example 2.

[0023] Figure 4 These are physical images and scanning electron microscope images of the microstructure of Example 10;

[0024] Figure 5 These are physical images of the melamine porous material matrix and scanning electron microscope (SEM) images of its microstructure. Detailed Implementation

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] The first aspect of the present invention provides a superhydrophobic melamine porous material containing hydrophobic groups; the hydrophobic groups include carbonyl groups.

[0027] In this invention, the melamine porous material, while maintaining the high resilience, high porosity, and heat resistance of the original three-dimensional porous polymer matrix, also possesses superhydrophobic properties.

[0028] According to a preferred embodiment of the present invention, the superhydrophobic melamine porous material has a saturated adsorption capacity for oil and gas of not less than 10 g / g, preferably not less than 13 g / g, for example, 13.1 g / g, 13.2 g / g, 13.3 g / g, 13.4 g / g, 13.5 g / g, 13.6 g / g, 13.7 g / g, 13.8 g / g, 13.9 g / g, 14.0 g / g, 14.1 g / g, 14 g / g, etc. .2g / g, 14.3g / g, 14.4g / g, 14.5g / g, 14.6g / g, 14.7g / g, 14.8g / g, 14.9g / g, 15.0g / g, 15.1g / g, 15.2g / g, 15.3g / g, 15.4g / g, 15.5g / g, 15.6g / g, 15.7g / g, 15.8g / g, 15.9g / g, 16.0g / g; The superhydrophobic melamine porous material exhibits a saturated adsorption capacity for oil and gas of no less than 10 g / g after 20 adsorption-desorption cycles, preferably no less than 13 g / g. For example, it can be 13.1 g / g, 13.2 g / g, 13.3 g / g, 13.4 g / g, 13.5 g / g, 13.6 g / g, 13.7 g / g, 13.8 g / g, 13.9 g / g, 14.0 g / g, 14.1 g / g, or 1 g / g. 4.2g / g, 14.3g / g, 14.4g / g, 14.5g / g, 14.6g / g, 14.7g / g, 14.8g / g, 14.9g / g, 15.0g / g, 15.1 g / g, 15.2g / g, 15.3g / g, 15.4g / g, 15.5g / g, 15.6g / g, 15.7g / g, 15.8g / g, 15.9g / g, 16.0g / g.

[0029] In this invention, the carbonyl group is obtained by converting the free amino group in the melamine backbone of the melamine porous material, and the carbonyl group is located on the melamine backbone.

[0030] In this invention, the superhydrophobic melamine porous material has a wide applicable temperature range, and especially maintains a large saturated adsorption capacity for oil and gas and good long-term separation effect even in high-temperature environments. According to a preferred embodiment of this invention, the saturated adsorption capacity of the superhydrophobic melamine porous material for oil at 60°C remains no less than 9 g / g after 20 adsorption-desorption cycles, preferably no less than 13 g / g, for example, 13.1 g / g, 13.2 g / g, 13.3 g / g, 13.4 g / g, 13.5 g / g, 13.6 g / g, 1... 3.7g / g, 13.8g / g, 13.9g / g, 14.0g / g, 14.1g / g, 14.2g / g, 14.3g / g, 14.4g / g, 14.5g / g, 14.6g / g, 14.7g / g, 14.8g / g, 14.9g / g, 15.0g / g, 15.1g / g, 15.2g / g, 15.3g / g, 15.4g / g, 15.5g / g, 15.6g / g, 15.7g / g, 15.8g / g, 15.9g / g, 16.0g / g.

[0031] In this invention, the superhydrophobic melamine porous material has flame-retardant and temperature-resistant properties. According to a preferred embodiment of this invention, the superhydrophobic melamine porous material has a UL-94 vertical burning test rating of V-0.

[0032] In this invention, the superhydrophobic melamine porous material has superhydrophobic properties. According to a preferred embodiment of this invention, the static planar contact angle of the superhydrophobic melamine porous material with water in air is not less than 125°, preferably not less than 135°.

[0033] According to a preferred embodiment of the present invention, the static contact angle of the superhydrophobic melamine porous material with white oil is not higher than 20°, preferably not higher than 10°.

[0034] According to a preferred embodiment of the present invention, the superhydrophobic melamine porous material has through pores.

[0035] In this invention, the pore size of the superhydrophobic melamine porous material can be selected from a wide range. According to a preferred embodiment of this invention, the pore size of the superhydrophobic melamine porous material is 50-800 μm, preferably 100-400 μm.

[0036] In this invention, the porosity of the superhydrophobic melamine porous material can be selected from a wide range. According to a preferred embodiment of this invention, the porosity of the superhydrophobic melamine porous material is greater than or equal to 80%, preferably greater than or equal to 93%, and more preferably 93%-98%.

[0037] In this invention, all superhydrophobic melamine porous materials possessing the aforementioned properties can achieve the objectives of this invention, and there are no special requirements for their preparation methods. Regarding this invention, according to a preferred embodiment, this invention provides a method for preparing the aforementioned superhydrophobic melamine porous material, the method comprising:

[0038] The superhydrophobic melamine porous material was obtained by contacting the melamine porous material matrix with an acid solution, followed by microwave irradiation, washing, and drying.

[0039] The contact time is 0.5s-100s;

[0040] Microwave irradiation conditions include: irradiation power of 100-2000W; irradiation time of 20s-20min. In this invention, the preparation method of the superhydrophobic melamine porous material described herein is used. After the hydrophilic groups in the melamine porous material matrix selectively absorb microwave energy, they partially hydrolyze into hydrophobic groups. Controlling the hydrolysis rate allows the melamine porous material to possess superhydrophobic properties while maintaining the high resilience, high porosity, and heat resistance of the original three-dimensional porous polymer matrix. This ensures that the superhydrophobic melamine porous material described in this application exhibits virtually no decrease in its adsorption capacity for oil and gas after 20 cycles of use.

[0041] In the melamine porous material matrix, the free amino groups in the melamine skeleton and the ether bonds connecting the melamine skeleton are all hydrophilic groups. In this invention, the hydrophobic groups are obtained by hydrolysis of the hydrophilic groups in the melamine porous material matrix. According to a preferred embodiment of the present invention, the hydrolysis rate is 5%-85%, preferably 10%-60%, and more preferably 15%-50%. A hydrolysis rate in the range of 15%-50% is beneficial to improving the oil and gas adsorption efficiency of the superhydrophobic melamine porous material during long-term operation.

[0042] According to a preferred embodiment of the present invention, the hydrophilic group is selected from ether bonds and amino groups.

[0043] After selectively absorbing microwave energy, the hydrophilic groups in the melamine porous material matrix partially hydrolyze into hydrophobic groups, and the free amino groups in the melamine skeleton are converted into carbonyl groups; the ether bonds (~HN-COC-NH~) connecting the melamine skeleton are converted into ~HN-CH2-NH~ structures.

[0044] In this invention, the purpose of the invention can be achieved with an acid solution concentration in the range of 0.01-3 mol / L. For example, it can be 0.08 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L, or 1.8 mol / L. Preferably, the acid solution concentration is 0.05-2 mol / L, and more preferably 0.05-1.5 mol / L, which is beneficial to improving the oil and gas adsorption efficiency of the superhydrophobic melamine porous material during long-term operation.

[0045] According to a preferred embodiment of the present invention, the contact time is 0.5s-10s, for example, it can be 0.8s, 1.0s, 2.0s, 3.0s, 4.0s, 5.0s, 6.0s, 7.0s, 8.0s, or 9.0s.

[0046] In this invention, microwave irradiation power ranging from 100 to 2000W can achieve the purpose of this invention. For example, it can be 200W, 300W, 400W, 500W, 600W, 700W, 900W, 1000W, 1100W, 1200W, 1300W, 1400W, 1500W, 1600W, or 1700W, preferably 100-1800W.

[0047] In this invention, the microwave irradiation can be carried out in various microwave reactors that are already available in the prior art.

[0048] According to a preferred embodiment of the present invention, the microwave irradiation conditions include an irradiation time of 2 min to 10 min.

[0049] In this invention, there is no particular limitation on the type of acid. According to a preferred embodiment of the invention, the acid in the acid solution is selected from one or more inorganic acids and organic acids.

[0050] According to a preferred embodiment of the present invention, the inorganic acid is selected from at least one of hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, boric acid and phosphoric acid, preferably at least one of hydrochloric acid and sulfuric acid;

[0051] According to a preferred embodiment of the present invention, the organic acid is selected from at least one of acetic acid, citric acid, formic acid and oxalic acid, preferably citric acid and / or acetic acid.

[0052] According to a preferred embodiment of the present invention, the acid is selected from one or more of hydrochloric acid, citric acid, acetic acid and sulfuric acid.

[0053] According to a preferred embodiment of the present invention, the acid is selected from one or more of hydrochloric acid, citric acid, acetic acid and sulfuric acid; the acid concentration is 0.05-0.5 mol / L; the contact time between the melamine porous material matrix and the acid solution is 2s-10s; the microwave irradiation time is 2min-10min; the preparation of superhydrophobic melamine porous material by the above method is beneficial to improving the adsorption efficiency of oil and gas, especially to improving the adsorption efficiency of oil and gas during long-term operation.

[0054] In this invention, there is no particular limitation on the contact method, as long as the acid solution can be fully contacted with the skeleton of the melamine porous material matrix. The contact method includes, but is not limited to, immersion, rinsing, spraying, etc. Immersion is preferred, so that the acid solution can be more evenly distributed in the sponge skeleton.

[0055] According to a preferred embodiment of the invention, the contact causes the melamine porous material matrix to become saturated or supersaturated with the liquid; the preferred contact method is immersion, rinsing or spraying, and more preferably immersion.

[0056] According to a preferred embodiment of the present invention, the melamine porous material matrix is ​​completely immersed in an acid solution for the contact, and then removed and subjected to microwave irradiation.

[0057] In this invention, washing is used to remove hydrolysis products and acids from the surface of the material. There are no particular limitations on the washing conditions and the amount of detergent used. In the implementation of this invention, washing with deionized water until the washing solution is neutral is used as an example, but this does not limit the scope of this invention.

[0058] In this invention, there are no particular limitations on the drying conditions, as long as the solvent after washing is removed without damaging the structure of the superhydrophobic melamine porous material. According to a preferred embodiment of the present invention, the drying conditions include: a drying temperature of 60-100°C and a drying time of 5-120 min. In the implementation of the present invention, drying at 60°C for 10 min is used as an example, but this does not limit the scope of the present invention.

[0059] In this invention, there is no particular limitation on the drying method. According to a preferred embodiment of the invention, the drying method is selected from vacuum drying, forced air drying or microwave drying; more preferably, microwave drying is preferred because it has higher evaporation efficiency and is more energy-efficient.

[0060] In this invention, after the melamine porous material matrix is ​​hydrolyzed and modified to obtain the superhydrophobic melamine porous material, it can basically maintain the excellent properties of the matrix itself. For example, the long-term temperature range of the superhydrophobic melamine porous material is -150-200℃; for example, the UL-94 vertical burning test rating of the superhydrophobic melamine porous material is V-0.

[0061] A third aspect of the present invention provides the application of the superhydrophobic melamine porous material described above in oil-gas separation and / or adsorption.

[0062] In the context of this invention, including the following embodiments, the oil and gas mainly comprises N2, with the remainder being non-methane hydrocarbons (e.g., benzene series compounds and C2-C5 hydrocarbons); wherein, by volume fraction, the N2 content is 95.0-99.8%; the benzene series compound content is 0.1-1%; and the C2-C5 hydrocarbon content is less than 0.1%. In these embodiments, the advantages of the invention are exemplified by oil and gas with a total non-methane hydrocarbon content of 1200 ppm.

[0063] In the context of this specification, including the following examples, the hydrolysis rate of the hydrophilic group was calculated by Agilent Micro-Infrared Spectroscopy using the ATR test mode. (Measured at 1625±5 cm⁻¹) -1 The fitted peak area at 1480 cm⁻¹ divided by 1480 cm⁻¹ -1 The ratio of the fitted peak area (S) is correlated with the hydrolysis rate (H). The hydrolysis rate of the unmodified sponge is 0%, and the hydrolysis rate of the fully hydrolyzed sample, i.e., the infrared peak area ratio does not increase with the modification time, is 100%. The calculation yields H = 1.2S * 100%, and then the hydrolysis rate is obtained according to the formula and the test ratios of various embodiments.

[0064] In the context of this specification, including the following embodiments, the vertical flammability test rating is tested according to the UL94 flame retardant test method.

[0065] In the context of this specification, including the following embodiments, the water contact angle parameter is measured using an EASY DROP contact angle tester from KRUSS GmbH, Germany, with a measurement range of 1-180° and a resolution of ±0.1°. The static contact angle measurement mode is used, with a fixed volume of 2μL of water or white oil droplets dropped onto the porous material each time. The calculated initial contact angle is taken as the contact angle measurement value of the porous material surface. Six parallel measurements are performed, and the average value is calculated.

[0066] In the context of this specification, including the following embodiments, the adsorption efficiency (η) and saturated adsorption capacity (Ф) of oil and gas are tested using the following steps: m1 g (mass fluctuation during testing in each of the following embodiments does not exceed 1%) of oil and gas adsorption material is weighed and placed at an oil and gas discharge port with a stable flow rate and a non-methane total hydrocarbon content of 1200 ppm for testing. The oil and gas adsorption material naturally fills the entire oil and gas discharge port. The non-methane total hydrocarbon content c at the pipeline outlet is tested for a certain period of time. The mass m2 of the oil and gas adsorption material when c remains constant is also considered.

[0067] Oil and gas adsorption efficiency

[0068] Saturated adsorption capacity

[0069] In the context of this specification, including the following examples, the adsorption and desorption tests are as follows: the adsorption test of the material is consistent with the saturated adsorption capacity test described above; then, the oil and gas adsorbent material after adsorption saturation is mechanically squeezed until no obvious droplets fall; the sponge is purged with low-pressure steam at 0.4 MPa and 160°C; and then microwave-dried until the material reaches constant weight. The mass of the material after the cycle is no more than 5% different from the mass before use; this completes one adsorption-desorption cycle.

[0070] Unless otherwise specified in the context of this invention, the saturated adsorption capacity of the superhydrophobic melamine porous material for oil and gas was tested at room temperature (25°C).

[0071] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention in any way. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this disclosure. Such structures and techniques have also been described in many publications.

[0072] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0073] In the following examples, the melamine porous material matrix was purchased from Beiyou Building Materials and is a melamine porous material with through pores.

[0074] Example 1

[0075] Prepare a 0.05 mol / L hydrochloric acid aqueous solution, immerse the melamine porous material matrix (porosity 95%, average pore size 100 μm) in the solution for 2 seconds, then remove it. After irradiation with 800 W microwave power for 4 minutes, remove it, wash with deionized water until the pH is neutral, microwave dry at 60℃ for 10 minutes to obtain superhydrophobic melamine porous material S1.

[0076] In the superhydrophobic melamine porous material S1, the hydrolysis rate of the hydrophilic group is 18%, the average pore size is 100μm, the porosity is 95%, the UL94 vertical flammability rating is V-0, the contact angle to white oil is 0°, and the contact angle to water is 138.3°.

[0077] The superhydrophobic melamine porous material S1 was tested according to the test requirements for saturated adsorption capacity, saturated adsorption capacity after 20 adsorption-desorption cycles, saturated adsorption capacity of oil at 60℃ after 20 adsorption-desorption cycles, and adsorption efficiency at different times. The results are shown in Table 1.

[0078] Physical images and SEM images of the superhydrophobic melamine porous material S1 are shown below. Figure 1 As shown, compared to the melamine porous material matrix (physical image and SEM image as shown) Figure 5 As shown in the figure, neither the porous material skeleton nor the overall size of the porous material changed significantly.

[0079] Figure 2 shows the infrared spectra of superhydrophobic melamine porous materials S1, S9, and S10, and the unmodified melamine porous material matrix. The 1628 cm⁻¹ value is among the 1628 cm⁻¹ values. -1 The characteristic peak at 1480 cm⁻¹ is a new peak generated after modification, that is, the characteristic peak of the hydrophobic group. -1 The peak at this point is the stretching vibration peak of the melamine ring. Since the modification did not destroy the melamine ring, its intensity remains unchanged. The area of ​​this peak can be used to characterize the initial content of hydrophilic groups.

[0080] The infrared spectrum is shown in Figure 2. Figure 2-B , Figure 2-C for Figure 2-A (A close-up view), 1540cm -1 This is the CN stretching vibration. According to the S9, S1, and S10 peaks, as the hydrolysis rate of the melamine porous material matrix increases and the degree of modification increases, this peak gradually weakens, while the peak at 1624 cm⁻¹... -1 The peak represents the stretching vibration of cyclic amides. This peak gradually increases, suggesting that the free amino groups on melamine-formaldehyde resin gradually hydrolyze into hydroxyl groups under acidic conditions. The hydroxyl groups on the melamine ring are unstable and exist as isomers of lactams.

[0081] In infrared spectrum 2C, 1141 cm⁻¹ -1 and 967cm -1 The absorption peaks are symmetric and antisymmetric in the COC bond. The intensity of these two absorption peaks gradually decreases with the increase of the hydrolysis rate of the melamine porous material matrix and the degree of modification, according to S9, S1, and S10, until they disappear. This indicates that after the melamine porous material matrix is ​​modified, the NCOCN structure in the melamine-formaldehyde sponge undergoes a deformaldehyde reaction to generate the NCN structure.

[0082] Example 2

[0083] Prepare a 0.5 mol / L hydrochloric acid aqueous solution, immerse the melamine porous material matrix (porosity 93%, average pore size 300 μm) in it for 5 s, then remove it and irradiate it with a microwave irradiation power of 1800 W for 2 min. After washing with deionized water until the pH is neutral, microwave dry it at a temperature of 80 °C for 80 min to obtain the superhydrophobic melamine porous material S2.

[0084] The infrared spectrum of the superhydrophobic melamine porous material S2 is similar to that of Example 1, with a hydrolysis rate of 50% for the hydrophilic groups. The superhydrophobic melamine porous material S2 has an average pore size of 300 μm, a porosity of 93.2%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 145.3°.

[0085] The superhydrophobic melamine porous material S2 was tested according to the test requirements for saturated adsorption capacity, saturated adsorption capacity after 20 adsorption-desorption cycles, saturated adsorption capacity of oil at 60℃ after 20 adsorption-desorption cycles, and adsorption efficiency at different times. The results are shown in Table 1.

[0086] Figure 3 The graphs show the thermogravimetric curves of superhydrophobic porous materials S1 and S2 and the unmodified melamine porous material matrix. As can be seen from the graphs, S1 and S2 have good temperature resistance, indicating that the modified materials have unchanged temperature resistance below 200℃ and can be recycled by steam purging.

[0087] Example 3

[0088] Prepare a 0.25 mol / L citric acid aqueous solution, immerse the melamine porous material matrix (porosity 96%, average pore size 400 μm) in the solution for 10 s, then remove it, irradiate it with a microwave power of 200 W for 10 min, wash it with deionized water until the pH is neutral, microwave dry it at a temperature of 60 °C for 50 min, and then remove it to obtain the superhydrophobic melamine porous material S3.

[0089] The infrared spectrum of the superhydrophobic melamine porous material S3 is similar to that of Example 1, with a hydrolysis rate of 35% for the hydrophilic groups. The superhydrophobic melamine porous material S3 has an average pore size of 400 μm, a porosity of 96.6%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 141.3°.

[0090] The superhydrophobic melamine porous material S3 was tested according to the test requirements for saturated adsorption capacity, saturated adsorption capacity after 20 adsorption-desorption cycles, saturated adsorption capacity of oil at 60℃ after 20 adsorption-desorption cycles, and adsorption efficiency at different times. The results are shown in Table 1.

[0091] Example 4

[0092] The method of Example 3 was followed, except that a 0.25 mol / L boric acid solution was used instead of a 0.25 mol / L citric acid aqueous solution; the other conditions were the same as in Example 3, and the superhydrophobic melamine porous material S4 was obtained.

[0093] The infrared spectrum of the superhydrophobic melamine porous material S4 is similar to that of Example 1, with a hydrolysis rate of 20% for the hydrophilic groups. In the superhydrophobic melamine porous material S4, the average pore size is 400 μm, the porosity is 96.1%, the UL94 vertical flammability rating is V-0, the contact angle to white oil is 0°, and the contact angle to water is 128.5°.

[0094] The superhydrophobic melamine porous material S4 was tested according to the test requirements for saturated adsorption capacity, saturated adsorption capacity after 20 adsorption-desorption cycles, saturated adsorption capacity of oil at 60℃ after 20 adsorption-desorption cycles, and adsorption efficiency at different times. The results are shown in Table 1.

[0095] Example 5

[0096] A 2 mol / L oxalic acid aqueous solution was prepared, and the melamine porous material matrix (porosity 95%, average pore size 100 μm) was immersed in it for 50 s and then removed. After that, it was irradiated with microwave power of 1800 W for 2 min and then removed. It was washed with deionized water until the pH was neutral, microwave dried, and the drying temperature was controlled at 60℃. After drying for 10 min, the superhydrophobic melamine porous material S5 was obtained.

[0097] The infrared spectrum of the superhydrophobic melamine porous material S5 is similar to that of Example 1, with a hydrolysis rate of 58% for the hydrophilic groups. The superhydrophobic melamine porous material S5 has an average pore size of 90 μm, a porosity of 86%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 139.7°.

[0098] The superhydrophobic melamine porous material S5 was tested according to the test requirements for saturated adsorption capacity, saturated adsorption capacity after 20 adsorption-desorption cycles, saturated adsorption capacity of oil at 60℃ after 20 adsorption-desorption cycles, and adsorption efficiency at different times. The results are shown in Table 1.

[0099] Example 6

[0100] Following the method of Example 1, except that the microwave irradiation time was 15 min, and the other conditions were the same as in Example 1, a superhydrophobic melamine porous material S6 was obtained.

[0101] The infrared spectrum of the superhydrophobic melamine porous material S6 is similar to that of Example 1, with a hydrolysis rate of 56% for the hydrophilic groups. In the superhydrophobic melamine porous material S6, the average pore size is 100 μm, the porosity is 84%, the UL94 vertical flammability rating is V-0, the contact angle to white oil is 0°, and the contact angle to water is 141.0°.

[0102] The superhydrophobic melamine porous material S6 was tested according to the test requirements for saturated adsorption capacity, saturated adsorption capacity after 20 adsorption-desorption cycles, saturated adsorption capacity of oil at 60℃ after 20 adsorption-desorption cycles, and adsorption efficiency at different times. The results are shown in Table 1.

[0103] Example 7

[0104] The method of Example 1 was followed, except that 0.05 mol / L nitric acid was used instead of 0.05 mol / L hydrochloric acid, and the other conditions were the same as in Example 1, to obtain the superhydrophobic melamine porous material S7.

[0105] The infrared spectrum of the superhydrophobic melamine porous material S7 is similar to that of Example 1, with a hydrolysis rate of 14% for the hydrophilic groups. The superhydrophobic melamine porous material S7 has an average pore size of 100 μm, a porosity of 93.3%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 138.7°.

[0106] The superhydrophobic melamine porous material S6 was tested according to the test requirements for saturated adsorption capacity, saturated adsorption capacity after 20 adsorption-desorption cycles, saturated adsorption capacity of oil at 60℃ after 20 adsorption-desorption cycles, and adsorption efficiency at different times. The results are shown in Table 1.

[0107] Example 8

[0108] The method of Example 1 was followed, except that the melamine porous material matrix (porosity of 95% and average pore size of 100 μm) was immersed in hydrochloric acid for 90 seconds and then removed. The other conditions were the same as in Example 1, and the superhydrophobic melamine porous material S8 was obtained.

[0109] The infrared spectrum of the superhydrophobic melamine porous material S8 is similar to that of Example 1, with a hydrolysis rate of 42% for the hydrophilic groups. The superhydrophobic melamine porous material S8 has an average pore size of 95 μm, a porosity of 88%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 139.2°.

[0110] The superhydrophobic melamine porous material S8 was tested according to the test requirements for saturated adsorption capacity, saturated adsorption capacity after 20 adsorption-desorption cycles, saturated adsorption capacity of oil at 60℃ after 20 adsorption-desorption cycles, and adsorption efficiency at different times. The results are shown in Table 1.

[0111] Example 9

[0112] Prepare a 0.01 mol / L hydrochloric acid aqueous solution, immerse the melamine porous material matrix in it for 2 seconds, and then remove it. After that, irradiate it with a microwave irradiation power of 200W for 20 seconds and then remove it for microwave drying. Control the drying temperature at 60℃ and dry for 60 minutes to obtain the superhydrophobic melamine porous material S9.

[0113] The infrared spectrum of the superhydrophobic melamine porous material S9 is similar to that of Example 1, with a hydrolysis rate of 5% for the hydrophilic groups. The superhydrophobic melamine porous material S9 has an average pore size of 100 μm, a porosity of 95%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 82.5°.

[0114] The superhydrophobic melamine porous material S9 was tested for saturated adsorption capacity and adsorption efficiency at different times according to the test requirements. The results are shown in Table 1.

[0115] Example 10

[0116] A 3 mol / L nitric acid aqueous solution was prepared, and the melamine porous material matrix was immersed in it for 60 seconds and then removed. After that, it was irradiated with a microwave irradiation power of 2000W for 10 minutes and then removed for microwave drying. The drying temperature was controlled at 60℃ and dried for 60 minutes to obtain the superhydrophobic melamine porous material S10.

[0117] The infrared spectrum of the superhydrophobic melamine porous material S10 is similar to that of Example 1, with a hydrolysis rate of 82% for the hydrophilic groups. The superhydrophobic melamine porous material S10 has an average pore size of 67 μm, a porosity of 53%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 147.8°.

[0118] The superhydrophobic melamine porous material S10 was tested for saturated adsorption capacity and adsorption efficiency at different times according to the test requirements. The results are shown in Table 1.

[0119] Figure 4 Here are the physical images and SEM images of the melamine porous material S10, compared to the superhydrophobic melamine porous material S1 ( Figure 1The porous material S10 underwent a certain degree of collapse, with a reduction in porosity and pore size. This indicates that under these conditions, the high hydrolysis rate of the hydrophilic groups reduced the rigidity of the porous material framework. Compared to the superhydrophobic melamine porous material S1, the saturated adsorption capacity of oil and gas decreased, and the long-term adsorption efficiency also decreased.

[0120] Comparative Example 1

[0121] The method is the same as in Example 1, except that microwave irradiation is not performed. Specifically:

[0122] Prepare a 0.05 mol / L hydrochloric acid aqueous solution, immerse the melamine porous material matrix (porosity 95%, average pore size 100 μm) in the solution for 2 seconds, remove it, let it stand for 4 minutes, wash it with deionized water until the pH is neutral, microwave dry it at 60℃ for 10 minutes to obtain melamine porous material D1.

[0123] In melamine porous material D1, the hydrolysis rate of hydrophilic groups is 0, the average pore size is 100 μm, and the porosity is 95%.

[0124] The adsorption efficiency of melamine porous material D1 was tested at different times according to the test requirements, and the results are shown in Table 1.

[0125] Comparative Example 2

[0126] The method of Example 2 differs in that microwave irradiation is not performed; specifically:

[0127] Prepare a 0.5 mol / L hydrochloric acid aqueous solution, immerse the melamine porous material matrix (porosity 93%, average pore size 300 μm) in it for 5 seconds, remove it, let it stand for 2 minutes, wash it with deionized water until the pH is neutral, and then microwave dry it at 80℃ for 80 minutes to obtain melamine porous material D2.

[0128] In melamine porous material D2, the hydrolysis rate of hydrophilic groups is 0%, the average pore size is 300 μm, and the porosity is 93%.

[0129] The adsorption efficiency of melamine porous material D2 was tested at different times according to the test requirements, and the results are shown in Table 1.

[0130] Comparative Example 3

[0131] The adsorption efficiency of the unmodified melamine porous material matrix was tested at different time points according to the test requirements, and the results are shown in Table 1.

[0132] Comparative Example 4

[0133] The adsorption efficiency of activated carbon was tested at different times according to the test requirements, and the results are shown in Table 1.

[0134] Table 1

[0135]

[0136]

[0137] As can be seen from the results in Table 1, the superhydrophobic melamine porous material prepared by the present invention has a high saturated adsorption capacity for oil and gas and a long-term high adsorption efficiency, and can produce good results in the adsorption and separation of oil vapor.

[0138] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A superhydrophobic melamine porous material, characterized in that, The melamine porous material contains hydrophobic groups; the hydrophobic groups include carbonyl groups. 2.The super-hydrophobic melamine porous material according to claim 1, wherein, the hydrophobic groups are obtained by hydrolysis of hydrophilic groups in the melamine porous material matrix, the hydrophilic groups being selected from ether bonds and amino groups; the super-hydrophobic melamine porous material has a saturated adsorption capacity for oil and gas of no less than 10 g / g; the super-hydrophobic melamine porous material still has a saturated adsorption capacity for oil and gas of no less than 10 g / g after 20 cycles of adsorption-desorption; Preferably, the super-hydrophobic melamine porous material has a saturated adsorption capacity for oil and gas of no less than 9 g / g at 60 ℃ after 20 cycles of adsorption-desorption. 3.The super-hydrophobic melamine porous material according to claim 1 or 2, wherein, the super-hydrophobic melamine porous material has a UL-94 vertical burning test rating of V-0; and / or the super-hydrophobic melamine porous material has a static planar contact angle with water in air of no less than 125°, preferably no less than 135°; and / or the super-hydrophobic melamine porous material has a static contact angle with white oil of no more than 20°. 4.The super-hydrophobic melamine porous material according to claim 1 or 2, wherein, the super-hydrophobic melamine porous material has through-holes; Preferably, the super-hydrophobic melamine porous material has a pore size of 50-800 μm, preferably 100-400 μm; and / or the super-hydrophobic melamine porous material has a porosity of no less than 80%, preferably no less than 93%.

5. The method of producing a superhydrophobic melamine porous material according to any one of claims 1 to 4, characterized in that, The method comprises: contacting the melamine porous material matrix with an acid solution, followed by microwave irradiation, washing and drying to obtain the super-hydrophobic melamine porous material; the contacting time is 0.5-100 s; the microwave irradiation conditions include: irradiation power of 100-2000 W; and irradiation time of 20 s-20 min. 6.The method according to claim 5, wherein, the hydrophobic groups are obtained by hydrolysis of hydrophilic groups in the melamine porous material matrix, the hydrolysis rate being 5%-85%, preferably 10%-60%, more preferably 15%-50%; Preferably, the hydrophilic groups are selected from ether bonds and amino groups. 7.The method according to claim 5 or 6, wherein, the acid solution has a concentration of 0.01-3 mol / L, preferably 0.05-1.5 mol / L; and / or the contacting time is 0.5 s-10 s; and / or the microwave irradiation conditions include: irradiation power of 100-1800 W; and / or irradiation time of 2 min-10 min; the contacting causes the melamine porous material matrix to saturate or supersaturate the liquid; preferably, the contacting is immersion, leaching or spraying, preferably immersion. 8.The method according to any one of claims 5-7, wherein, the acid in the acid solution is selected from one or more of inorganic acids and organic acids; Preferably, the inorganic acid is selected from at least one of hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, boric acid and phosphoric acid, preferably at least one of hydrochloric acid and sulfuric acid; Preferably, the organic acid is selected from at least one of acetic acid, citric acid, formic acid and oxalic acid; More preferably, the acid is selected from one or more of hydrochloric acid, citric acid, acetic acid and sulfuric acid.

9. The preparation method according to any one of claims 5-8, wherein, The drying condition comprises: a drying temperature of 60-100℃; and a drying time of 5-120 min. Preferably, the drying method is selected from vacuum drying, air blast drying or microwave drying; more preferably, microwave drying.

10. Use of the superhydrophobic melamine porous material according to any one of claims 1-4 in oil-gas separation and / or adsorption.

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