Salt-responsive porous composite material and preparation method and application thereof

Abstract

The application provides a salt-responsive porous composite material and a preparation method and application thereof. The porous composite material is obtained by combining pyridine salt positive ions in a rigid polymer and carboxylate negative ions of a polyurethane polymer through electrostatic interaction. The porous composite material not only has the structural stability of a rigid adsorption material, but also has the salt response performance and high adsorption performance of a flexible adsorption material, and the like, and realizes efficient adsorption of oil in a water environment. The salt-responsive porous composite material has an adsorption capacity of n-hexane of more than 10 g / g, and can be up to 49.3 g / g.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials technology, and in particular to a salt-responsive porous composite material, its preparation method, and its application. Background Technology

[0002] Oil is one of the three fossil fuels, but its distribution is extremely uneven overall. The Middle East alone accounts for 68% of recoverable reserves, and my country's oil reserves are limited. 45% of the Earth's proven recoverable oil resources are buried on the seabed. In the future, the center of the world's proven oil reserves will gradually shift from land to the ocean. However, extracting seabed oil faces many challenges. For example, traditional extraction methods such as deep-sea drilling are prone to oil spills, damaging the marine ecosystem. Therefore, protecting the marine environment is crucial in the process of offshore oil extraction, and there is an urgent need to find a new material for the sustainable development of marine resources.

[0003] Compared to freshwater environments such as rivers, lakes, and streams, seawater contains salt, and its salinity increases with depth, providing a suitable environment for the preparation of salt-responsive smart materials. Polyethylene glycol (PEG), as a classic flexible salt-responsive material, possesses the property of forming hydrogen bonds with water molecules, exhibiting a hydrophilic porous polymer structure in freshwater. With increasing salt concentration, the polymer continuously dehydrates, agglomerating into a lipophilic surface, promoting oil adsorption. However, the surface of most adsorbent materials is buried by the polymer, resulting in extremely low lipophilic porosity, severely affecting adsorption efficiency and crude oil refining. Conversely, rigid ionic framework materials have higher porosity and ordered pore distribution, but poor solubility and dispersibility, leading to poor adsorption capacity.

[0004] Therefore, there is a need to provide an adsorption material with high crude oil adsorption capacity and stable structure. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing adsorbent materials, which cannot simultaneously achieve both oil absorption performance and adsorption stability in seawater, thus hindering further increases in the adsorption capacity for crude oil. This invention provides an adsorbent material capable of high crude oil adsorption in seawater. The salt-responsive porous composite material of this invention is a complex formed by the electrostatic interaction of a rigid porous cationic polymer with a specific structure and a flexible polyurethane. In deep-sea areas with high salinity, the porous composite material exhibits hydrophobic pore surfaces, demonstrating highly efficient adsorption performance for hydrocarbons such as n-hexane. In freshwater areas with low salinity, the adsorption surface becomes hydrophilic, releasing lipophilic oil, making it suitable for offshore oil extraction.

[0006] Another object of the present invention is to provide a method for preparing the salt-responsive porous composite material.

[0007] Another object of the present invention is to provide the application of the salt-responsive porous composite material in the field of oil extraction.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A salt-responsive porous composite material comprises a rigid porous cationic polymer and an amphiphilic polyurethane attached thereto, wherein the rigid porous cationic polymer has a structure as shown in Formula I, and the amphiphilic polyurethane has a structure as shown in Formula II.

[0010]

[0011] In Formula I, X1, X2, and X3 are independently selected from F, Cl, or Br elements.

[0012] The porous composite material of this invention is obtained by electrostatic bonding of pyridinium salt cations in a rigid polymer and carboxylate anions in a polyurethane polymer. The rigid polymerization forms a porous structure with a certain degree of rigidity, enabling it to withstand pressure in deep-sea environments and maintain its pore structure, thereby adsorbing higher concentrations of crude oil. Meanwhile, the polyurethane polymer is amphiphilic (both hydrophilic and oleophilic), allowing for the adjustment of the distribution of different chain segments on the surface of the rigid polymer according to the salt concentration in seawater, thus achieving the adsorption and release of crude oil.

[0013] The polyurethane material of the present invention is salt-responsive and does not affect the adsorption effect of crude oil by clogging the pores of rigid porous cationic polymers.

[0014] Preferably, the vesicle pore size of the salt-responsive porous composite material is 400-1300 nm.

[0015] The porosity and pore size of the salt-responsive porous composite material are within the above-mentioned suitable range, which is conducive to the adsorption of more crude oil.

[0016] Preferably, in the salt-responsive porous composite material, the molar ratio of rigid porous cationic polymer to amphiphilic polyurethane is 1:(1-3). Adjusting the ratio of rigid porous cationic polymer to amphiphilic polyurethane can regulate the adhesion and distribution of amphiphilic polyurethane on the surface of rigid porous cationic polymer, as well as the size of the vesicles, thereby enabling it to adapt to oil extraction in seawater with different salinity and depth.

[0017] This invention also protects a method for preparing the salt-responsive porous composite material, comprising the following steps:

[0018] A rigid porous cationic polymer is dispersed in water to form mixture A; an amphiphilic polyurethane is dissolved in an organic solvent to form mixture B; mixture A and mixture B are mixed evenly, and after the reaction is completed at 20-30°C, the water and organic solvent are removed to obtain the salt-responsive porous composite material.

[0019] Optionally, the organic solvent includes, but is not limited to, at least one of tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0020] Preferably, the preparation method of the rigid porous cationic polymer includes the following steps: mixing and dispersing pyromellitic trimethylamide ethylpyridine, an acid-binding agent and an organic salt containing X1, X2 and X3 in a solvent, reacting at 0-4℃ for 5-7 hours, and obtaining the porous cationic polymer after separation and purification.

[0021] Solvents used to prepare porous cationic polymers include, but are not limited to, at least one of N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA).

[0022] Preferably, common separation methods in the art can be used in the preparation of porous cationic polymers, including but not limited to centrifugation.

[0023] The purification method used was column chromatography, and the eluent was a mixture of methanol and dichloromethane in a volume ratio of 1:10-20.

[0024] Preferably, the preparation method of the amphiphilic polyurethane includes the following steps:

[0025] S1. Dissolve polyethylene glycol, isophorone isocyanate, and catalyst in a solvent, and react at 60-100℃ for 5-7 hours in an inert atmosphere to obtain an intermediate;

[0026] S2. After mixing 2,2-bis(hydroxymethyl)butyric acid and the intermediate obtained in step S1 in a solvent, react at 60-100℃ for 3-6 hours, adjust the pH to 6.5-7.5 at 20-30℃, remove the solvent, and purify to obtain the amphiphilic polyurethane.

[0027] In the preparation of amphiphilic polyurethane, in step S1: the catalyst includes, but is not limited to, dibutyltin dilaurate; the gas forming the inert atmosphere includes, but is not limited to, at least one of nitrogen, argon, and helium.

[0028] In the preparation of amphiphilic polyurethane, in step S2, the solvent used to adjust the pH includes, but is not limited to, at least one of ammonia and triethylamine;

[0029] In the preparation of amphiphilic polyurethane, the solvents described in steps S1 and S2 independently include at least one of acetone, N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA).

[0030] In the preparation of amphiphilic polyurethane, the purification method is recrystallization, the good solvent used is tetrahydrofuran, and the poor solvent is petroleum ether.

[0031] It should be noted that in amphiphilic polyurethane, the raw material polyethylene glycol corresponds to a polyethylene glycol segment with a degree of polymerization of 'a'.

[0032] The application of the aforementioned salt-responsive porous composite material in the field of oil extraction is also within the scope of protection of this invention.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] The porous composite material of this invention is obtained by electrostatic bonding of pyridinium salt cations in a rigid polymer and carboxylate anions in a polyurethane polymer. It combines the advantages of both rigid and flexible adsorbent materials, while also exhibiting salt responsiveness, achieving highly efficient adsorption of oils in an aqueous environment.

[0035] The salt-responsive porous composite material of the present invention has an adsorption capacity of more than 10 g / g for n-hexane, and can reach as high as 49.3 g / g. Attached Figure Description

[0036] Figure 1 Transmission electron microscopy (TEM) image of the salt-responsive porous composite material prepared in Example 1;

[0037] Figure 2 The 1H NMR spectrum of the rigid porous cationic polymer used in Example 1 ( 1 H-NMR spectrum, specific data are as follows: 1 H-NMR (400MHz, D6-DMSO, δ, ppm) 8.80 (t, J = 6.3Hz, 3H), 8.46 (d, J = 1.8Hz, 3H), 8.42 (dd, J = 1. 8Hz, 6.2Hz, 3H), 8.34 (s, 3H), 7.67 (m, 3H), 7.32 (m, 3H), 3.54 (m, 6H), 2.89 (t, J = 6.3Hz, 6H).

[0038] Figure 3 The atomic force (AFM) diagram of the salt-responsive porous composite material prepared in Example 1 in a saturated sodium bromide solution is shown. Detailed Implementation

[0039] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and accompanying drawings. However, the embodiments do not limit the invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in this invention are conventional reagents, methods, and equipment in this technical field. Unless otherwise specified, all reagents and materials used in this invention are commercially available.

[0040] Example 1

[0041] This embodiment provides a salt-responsive porous composite material, the preparation method of which includes the following steps:

[0042] A rigid porous cationic polymer was dispersed in water to form mixture A (the concentration of the porous cationic polymer was 0.1 wt%); an amphiphilic polyurethane was dissolved in tetrahydrofuran to form mixture B (the concentration of the amphiphilic polyurethane was 0.1 wt%).

[0043] Mixture A and mixture B are stirred and mixed evenly at a molar ratio of porous cationic polymer to amphiphilic polyurethane of 1:0.5. After stirring and reacting at room temperature (25°C) for 24 hours, water and organic solvent (tetrahydrofuran) are removed by rotary evaporation to obtain the salt-responsive porous composite material.

[0044] The preparation method of the rigid porous cationic polymer includes the following steps:

[0045] 1 mol of pyromellitic ethylpyridine, 3 mol of acid-binding agent N,N'-diisopropylethylamine, and 3 mol of 1,4-di(bromomethyl)benzene were dissolved in DMF and reacted at 0°C for 6 h. Then, the solvent DMF was removed by rotary evaporation at 80°C. The rigid porous cationic polymer was obtained by purification by column chromatography (using methanol and dichloromethane as eluents in a volume ratio of 1:10).

[0046] The preparation method of amphiphilic polyurethane includes the following steps:

[0047] S1. Polyethylene glycol 1000, isophorone diisocyanate, and dibutyltin dilaurate catalyst were dissolved in acetone solvent and reacted at 90°C for 7 h under nitrogen atmosphere to obtain intermediate.

[0048] The molar ratio of polyethylene glycol 1000 to isophorone diisocyanate is 1:2; based on polyethylene glycol 1000 and isophorone diisocyanate, the amount of catalyst added is 0.76 ppm.

[0049] S2. Dissolve 2,2-bis(hydroxymethyl)butyric acid in DMF, slowly add it to the intermediate obtained in step S1, mix well, react at 90°C for 4 hours, adjust the pH to 7.0 at room temperature, remove the solvent by rotary evaporation, and recrystallize (the good solvent for recrystallization is tetrahydrofuran, and the poor solvent is petroleum ether) to obtain the amphiphilic polyurethane shown in Formula II.

[0050] Example 2

[0051] This embodiment provides a salt-responsive porous composite material, prepared according to the method of Example 1, except that the molar ratio of porous cationic polymer to amphiphilic polyurethane is 1:1.

[0052] Example 3

[0053] This embodiment provides a salt-responsive porous composite material, prepared according to the method of Example 1, except that the molar ratio of porous cationic polymer to amphiphilic polyurethane is 1:3.

[0054] Example 4

[0055] This embodiment provides a salt-responsive porous composite material, prepared according to the method of Example 1. The difference from Example 1 is that, in the preparation process of the rigid porous cationic polymer, 1,4-di(bromomethyl)benzene is replaced with an equimolar amount of 1,4-di(bisfluoromethyl)benzene.

[0056] Comparative Example 1

[0057] This comparative example provides a salt-responsive porous composite material, prepared according to the method of Example 1, except that the amphiphilic polyurethane is replaced with an equimolar amount of a sulfonic acid-type amphiphilic polymer prepared by the following method:

[0058] 0.363 g of Span 80 and 1.089 g of Tween 80 were dispersed in 20 mL of n-hexane to form a continuous phase. 0.52 g of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 0.267 g of N-(3-aminopropyl)methacrylamide, 0.056 g of N,N'-methylenebisacrylamide, 0.04 g of sodium tetrabromopapaate, and 0.023 g of ammonium persulfate were dissolved in 1.6 g of deionized water to form a dispersed phase solution. This solution was placed in an ice-water bath and sonicated at 425 W for 15 min to obtain a reverse-phase fine emulsion. Then, 0.056 g of N,N,N',N'-tetramethylenediamine was added. After purging with nitrogen for 5 min, polymerization was carried out at 40 °C for 8 h to obtain a sulfonic acid-type amphiphilic polymer.

[0059] Performance testing

[0060] The structure and properties of the salt-responsive porous composite materials prepared in the above embodiments and comparative examples were characterized. The specific test items, test methods, and results are as follows:

[0061] 1. Structural characterization: The transmission electron microscope (TEM) image of the salt-responsive porous composite material prepared in Example 1 is shown below. Figure 1 ; 1H NMR spectrum of rigid porous cationic polymers ( 1 (H-NMR) image see Figure 2 ;

[0062] 2. Vesicle pore size (nm) test of composite material: The obtained salt-responsive porous composite material was uniformly dispersed in water at a mass concentration of 0.1%wt. The sample was obtained by atomic force microscopy and dynamic light scattering test. The results are shown in Table 1.

[0063] 3. 1 mg of the salt-responsive porous composite material prepared in the above examples and comparative examples was added to saturated sodium bromide containing n-hexane (100 mg of n-hexane), and the adsorption capacity (g / g) of n-hexane was tested. The test results are shown in Table 1. After the adsorption saturation of the salt-responsive porous composite material was desorbed, the above adsorption operation was repeated, and the retention rate α of the adsorption capacity of the salt-responsive porous composite material for n-hexane after the 5th adsorption saturation was tested. α (%) = (initial saturated adsorption capacity - saturated adsorption capacity of the 5th adsorption) / initial saturated adsorption capacity * 100%. The test results are shown in Table 1.

[0064] Table 1

[0065]

[0066] The results above show that:

[0067] The salt-responsive porous composite material prepared by this invention exhibits good dispersion uniformity in a salt water environment, and its adsorption capacity for n-hexane is above 10 g / g, reaching as high as 49.3 g / g. It also has good adsorption stability, and after 5 cycles of adsorption, the adsorption performance can still be maintained above 99%.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A salt-responsive porous composite material, characterized in that, The mixture comprises a rigid porous cationic polymer and an amphiphilic polyurethane attached to its surface, wherein the rigid porous cationic polymer has a structure as shown in Formula I, and the amphiphilic polyurethane has a structure as shown in Formula II. Formula I; Formula II; In Formula I, X1, X2, and X3 are independently selected from the Br element; The preparation method of the salt-responsive porous composite material includes the following steps: The rigid porous cationic polymer is dispersed in water to form mixture A; the amphiphilic polyurethane is dissolved in an organic solvent to form mixture B; Mix mixture A and mixture B thoroughly, and after the reaction is complete at 20-30°C, remove water and organic solvent to obtain the salt-responsive porous composite material. The preparation method of the rigid porous cationic polymer includes the following steps: mixing and dispersing pyromellitic trimethylamide ethylpyridine, an acid-binding agent and 1,4-di(bromomethyl)benzene in a solvent, reacting at 0-4℃ for 5-7 h, and then separating and purifying to obtain the porous cationic polymer; The preparation method of the amphiphilic polyurethane includes the following steps: S1. Dissolve polyethylene glycol, isophorone isocyanate, and catalyst in a solvent, and react at 60-100℃ for 5-7 hours in an inert atmosphere to obtain an intermediate; S2. After mixing 2,2-bis(hydroxymethyl)butyric acid and the intermediate obtained in step S1 in a solvent, react at 60-100℃ for 3-6 hours, adjust the pH to 6.5-7.5 at 20-30℃, remove the solvent, and purify to obtain the amphiphilic polyurethane.

2. The salt-responsive porous composite material according to claim 1, characterized in that, The salt-responsive porous composite material contains vesicles with a pore size of 400-1300 nm.

3. The salt-responsive porous composite material according to claim 1, characterized in that, The molar ratio of rigid porous cationic polymer to amphiphilic polyurethane is 1:(1-3).

4. The salt-responsive porous composite material according to claim 1, characterized in that, The organic solvent includes at least one of tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide.

5. The application of the salt-responsive porous composite material according to any one of claims 1-4 as an adsorbent in oil extraction.

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