Polymeric ionic liquid for phenol adsorption and method for preparing the same
By preparing porous polymeric ionic liquid materials, the problems of poor selectivity and low adsorption capacity of existing coal tar phenol adsorbent materials have been solved, achieving efficient and selective adsorption and separation of phenolic compounds in coal tar, which has good prospects for industrial application.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTHWEST UNIV
- Filing Date
- 2025-12-23
- Publication Date
- 2026-06-19
AI Technical Summary
Existing coal tar phenol adsorbents suffer from poor selectivity, low adsorption capacity, and simple pore structure, making it difficult to efficiently and selectively separate phenolic compounds from complex coal tar.
The polymeric ionic liquid, formed by chemical bonding between a porous polymer framework composed of styrene and stilbene and quaternary ammonium salt groups, has a hierarchical porous structure and high specific surface area. It achieves highly selective adsorption through multiple interactions such as hydrogen bonding and ion-dipole interactions.
It achieves high adsorption capacity and excellent selectivity for phenolic compounds such as phenol, cresol, and xylenol in coal tar. The preparation method is simple and the conditions are mild, making it suitable for large-scale production.
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Figure CN122234280A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of functional polymer materials and adsorption separation technology, specifically to a polymeric ionic liquid material for the efficient and selective adsorption and separation of phenolic compounds from complex systems such as coal tar, and its preparation method. Technical Background
[0002] Coal tar is an important byproduct of coal dry distillation. Its composition is extremely complex, containing hundreds of organic compounds, among which phenolic compounds (such as phenol, cresol, and xylenol) are high-value chemical raw materials widely used in the synthesis of resins, pesticides, pharmaceuticals, and dyes. Therefore, the efficient and selective separation and extraction of phenolic compounds from coal tar is of great significance for improving the comprehensive utilization value of coal resources and reducing environmental pollution.
[0003] Currently, the main methods for extracting phenolic substances from coal tar include alkaline washing, extraction, distillation, and adsorption. Alkaline washing (sodium phenolate method) is the most commonly used method in industry, but it has inherent drawbacks such as a long process, high acid and alkali consumption, secondary pollution caused by phenol-containing wastewater, and limited purity of phenolic products. Extraction requires high selectivity of the extractant and has high energy consumption for solvent recovery. Distillation is suitable for separating components with large differences in boiling points, but its separation effect on phenolic homologues with similar boiling points in coal tar (such as cresol isomers) is limited, and it also has high energy consumption. Adsorption, due to its relatively simple operation, mild conditions, and high selectivity potential, is considered a promising alternative or supplementary technology.
[0004] In terms of adsorption methods, traditional adsorbents such as activated carbon, alumina, molecular sieves, and polymer resins have been studied for phenol adsorption. However, for coal tar systems with complex compositions, these materials generally face the following key challenges: (1) Insufficient selectivity: It is difficult to achieve high selective recognition and adsorption of phenols in coexisting components such as a large number of aromatic hydrocarbons and nitrogen-containing / sulfur-containing heterocyclic compounds; (2) Limited adsorption capacity: The specific surface area and pore structure are often not specifically designed, and the actual adsorption capacity for phenol molecules needs to be improved; (3) Poor pore adaptability: The molecular size distribution of phenolic compounds in coal tar is relatively wide, and a single microporous or mesoporous structure is difficult to achieve efficient mass transfer and adsorption of all target phenols; (4) Difficulty in regeneration and stability issues: In the harsh compositional environment of coal tar, adsorbents are easily contaminated or structurally damaged, and their recycling performance declines.
[0005] Polyionic liquids, as a novel type of material combining the functionality of ionic liquids and the mechanical stability of polymers, possess strong structural designability. By introducing specific functional groups to generate multiple interactions with target molecules (such as hydrogen bonding, ion-dipole, π-π stacking, etc.), they hold promise for achieving highly selective adsorption of phenolic compounds. However, existing polyionic liquid materials, when applied to phenol extraction from coal tar, still suffer from problems such as low specific surface area, simple pore structure (lacking hierarchical channels), insufficient adsorption capacity for typical phenols in coal tar (especially cresol and xylenol with larger molecular weights), and unclear stability and regenerability in complex oil phase environments.
[0006] Therefore, developing a specialized adsorbent material with high specific surface area, hierarchical pore structure, abundant active sites, excellent selectivity and good stability to meet the industrial demand for efficient and selective adsorption and separation of phenolic compounds in coal tar has become an urgent technical problem to be solved in this field. Summary of the Invention
[0007] The purpose of this invention is to address the problems of poor selectivity, low adsorption capacity, and simple pore structure in existing coal tar phenol adsorbents by providing a polymeric ionic liquid for phenol adsorption and its preparation method. This polymeric ionic liquid possesses a hierarchical pore structure and high specific surface area, exhibiting high adsorption capacity and excellent selectivity for phenolic compounds such as phenol, cresol, and xylenol in coal tar.
[0008] To address the above-mentioned problems, the present invention provides the following technical solution:
[0009] A polymeric ionic liquid for phenol adsorption, characterized in that the polymeric ionic liquid is formed by chemical bonding of a porous polymer framework formed by the polymerization of styrene and stilbene with quaternary ammonium salt groups, having the structure shown in Formula I:
[0010] Formula I.
[0011] Furthermore, the polymeric ionic liquid possesses microporous, mesoporous, and macroporous structures, with a BET specific surface area of 400-800 m²·g⁻¹.
[0012] Furthermore, the quaternary ammonium salt group in the polymeric ionic liquid is a quaternary ammonium salt formed by halogen and 1,4-diazabicyclo[2.2.2]octane.
[0013] Furthermore, the polymeric ionic liquid exhibits saturated adsorption capacities of greater than 500 mg·g⁻¹, 400 mg·g⁻¹, and 400 mg·g⁻¹ for phenol, cresol, and xylenol at room temperature, respectively.
[0014] The preparation method of the polyionic liquid is as follows:
[0015] (1) Stir monomer M1, crosslinking agent M2 and polar solvent at 300-800 rpm and mix them thoroughly at 40-60℃. The molar ratio of monomer M1 to crosslinking agent M2 is 0.5-2:1 and the concentration of monomer M1 is 0.5-2 mol / L.
[0016] (2) Nitrogen gas is introduced into the above mixture for protection, then an initiator is added, and then the temperature is raised to 80-120℃ for 12-24 h, wherein the molar ratio of the initiator to the monomer M1 is 0.01-0.1:1;
[0017] (3) The solid product obtained by filtration separation step (2) is washed with ethanol until the filtrate becomes clear, and then dried at 60-80℃ for 12-24 h;
[0018] (4) Disperse the product of step (3) in ethanol, then add 1,4-diazabicyclo[2.2.2]octane and reflux for 20-24 h, wherein the mass ratio of the product of step (3) to 1,4-diazabicyclo[2.2.2]octane is 4-10:1, and the mass ratio of ethanol to the product of step (3) is 5-10:1;
[0019] (5) After the reaction is complete, the solid product is separated by filtration and washed with ethyl acetate until the filtrate is clear. Then, it is dried in an oven at 80-100℃ for 12-24 h to obtain the polymeric ionic liquid.
[0020] Furthermore, the monomer M1 is one or more of 4-vinylbenzyl chloride and 4-vinylbenzyl bromide.
[0021] Furthermore, the crosslinking agent M2 is one or more of 1,4-divinylbenzene, 1,3-divinylbenzene, and 1,2-divinylbenzene.
[0022] Furthermore, the polar solvent is one of ethyl acetate, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.
[0023] Furthermore, the initiator is one of azobisisobutyronitrile, azobisisoheptane, benzoyl peroxide, and lauroyl peroxide.
[0024] The beneficial effects of this invention are as follows: The polymeric ionic liquid prepared by this invention possesses a rich hierarchical porous structure (micropores, mesopores, and macropores) and a high specific surface area (400-800 m²·g⁻¹), which is beneficial for the diffusion and adsorption of phenolic compounds, especially exhibiting excellent adsorption capacity for phenolic compounds of different molecular sizes in coal tar. The quaternary ammonium salt groups in the polymer backbone have various interactions with phenolic compounds, such as hydrogen bonds and ion-dipole interactions, endowing the material with excellent selective adsorption performance, enabling efficient separation of phenolic compounds from complex coal tar components. This polymeric ionic liquid exhibits high saturated adsorption capacity (greater than 500 mg·g⁻¹, 400 mg·g⁻¹, and 400 mg·g⁻¹, respectively) for typical coal tar phenolic compounds such as phenol, cresol, and xylenol, demonstrating excellent adsorption performance. The preparation method of this invention is simple, operates under mild conditions, and uses readily available raw materials, making it easy to scale up production and showing promising prospects for industrial applications. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0026] Figure 1 The N2 adsorption-desorption isotherms and pore size distributions of the polymeric ionic liquid A and the comparative example H of this invention are shown. Detailed Implementation
[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0028] Example 1
[0029] (1) Add 4-vinylbenzyl chloride (monomer M1, 0.5 mol), 1,4-divinylbenzene (crosslinking agent M2, 0.5 mol) and N,N-dimethylformamide (polar solvent, total volume 1 L) to the reactor and mix them evenly under stirring conditions of 40 ℃ and 500 rpm.
[0030] (2) Nitrogen gas was introduced into the mixture for 30 min, and azobisisobutyronitrile (initiator, 0.025 mol) was added. The mixture was heated to 100 °C and reacted for 18 h.
[0031] (3) After the reaction was completed, the solid product was collected by filtration, washed with ethanol until the filtrate was clear, and dried at 70 °C for 18 h to obtain the chlorine-containing porous polymer precursor.
[0032] (4) Disperse 10 g of the above precursor in 100 mL of ethanol, add 2 g of 1,4-diazabicyclo[2.2.2]octane, and reflux for 22 h;
[0033] (5) After the reaction is complete, the solid product is collected by filtration, washed with ethyl acetate until the filtrate is clear, and dried at 90 °C for 18 h to obtain polymeric ionic liquid product A.
[0034] Characterization revealed that Product A has a BET specific surface area of 650 m²·g⁻¹, exhibiting a hierarchical porous structure comprising micropores, mesopores, and macropores. At room temperature, its saturated adsorption capacity for p-phenol is 520 mg·g⁻¹, for p-cresol it is 430 mg·g⁻¹, and for xylenol it is 420 mg·g⁻¹.
[0035] Example 2
[0036] (1) Add 4-vinylbenzyl bromide (monomer M1, 1 mol), 1,3-divinylbenzene (crosslinking agent M2, 0.5 mol) and tetrahydrofuran (polar solvent, total volume 1 L) to the reactor and mix them evenly under stirring conditions of 50 °C and 600 rpm.
[0037] (2) Purge nitrogen gas into the mixture for 30 min, add benzoyl peroxide (initiator, 0.05 mol), and heat to 110 °C for 15 h;
[0038] (3) After the reaction was completed, the solid product was collected by filtration, washed with ethanol until the filtrate was clear, and dried at 75 °C for 20 h to obtain the bromine-containing porous polymer precursor.
[0039] (4) Disperse 10 g of the above precursor in 80 mL of ethanol, add 1.5 g of 1,4-diazabicyclo[2.2.2]octane, and reflux for 24 h;
[0040] (5) After the reaction is complete, the solid product is collected by filtration, washed with ethyl acetate until the filtrate is clear, and dried at 85 °C for 20 h to obtain polymeric ionic liquid product B.
[0041] Characterization revealed that product B has a BET specific surface area of 580 m²·g⁻¹ and exhibits a distinct hierarchical pore distribution. At room temperature, its saturated adsorption capacity for p-phenol is 510 mg·g⁻¹, for p-cresol it is 425 mg·g⁻¹, and for xylenol it is 415 mg·g⁻¹.
[0042] Example 3
[0043] (1) Add 4-vinylbenzyl chloride (monomer M1, 0.8 mol), 1,2-divinylbenzene (crosslinking agent M2, 0.8 mol) and 1,4-dioxane (polar solvent, total volume 1 L) to the reactor and mix them evenly under stirring conditions of 60 ℃ and 400 rpm;
[0044] (2) Pour nitrogen gas into the mixture for 30 min, add azobisisoheptanyl cyanide (initiator, 0.08 mol), and heat to 90℃ for 24 h;
[0045] (3) After the reaction was completed, the solid product was collected by filtration, washed with ethanol until the filtrate was clear, and dried at 65 °C for 24 h to obtain the chlorine-containing porous polymer precursor.
[0046] (4) Disperse 10 g of the above precursor in 120 mL of ethanol, add 2.5 g of 1,4-diazabicyclo[2.2.2]octane, and reflux for 20 h;
[0047] (5) After the reaction is complete, the solid product is collected by filtration, washed with ethyl acetate until the filtrate is clear, and dried at 100 °C for 12 h to obtain polymeric ionic liquid product C.
[0048] Characterization revealed that product C has a BET specific surface area of 720 m²·g⁻¹ and a well-developed pore structure. At room temperature, its saturated adsorption capacity for p-phenol is 540 mg·g⁻¹, for p-cresol it is 440 mg·g⁻¹, and for xylenol it is 430 mg·g⁻¹.
[0049] Example 4
[0050] (1) Add 4-vinylbenzyl chloride (monomer M1, 1.2 mol), 1,4-divinylbenzene (crosslinking agent M2, 0.6 mol) and N-methylpyrrolidone (polar solvent, total volume 1 L) to the reactor and mix them evenly under stirring at 45 °C and 700 rpm.
[0051] (2) After purging with nitrogen for 30 min, lauroyl peroxide (initiator, 0.06 mol) was added, and the temperature was raised to 115 °C and reacted for 20 h;
[0052] (3) After the reaction was completed, the product was filtered, washed with ethanol until clear, and dried at 65 °C for 20 h to obtain a chlorine-containing porous polymer precursor.
[0053] (4) Take 10 g of the precursor sample, disperse it in 70 mL of ethanol, add 1.0 g of 1,4-diazabicyclo[2.2.2]octane, and reflux for 23 h;
[0054] (5) The solid was collected by filtration, washed with ethyl acetate, and dried at 95 °C for 16 h to obtain polymeric ionic liquid product D.
[0055] According to N2 adsorption-desorption tests, product D has a BET specific surface area of 420 m²·g⁻¹, a total pore volume of 0.48 cm³ / g, and a well-balanced ratio of micropores to mesopores. At 25℃, its saturated adsorption capacity for phenol is 505 mg·g⁻¹, for m-cresol it is 418 mg·g⁻¹, and for 3,5-xylenol it is 398 mg·g⁻¹.
[0056] Example 5
[0057] (1) Add 4-vinylbenzyl bromide (monomer M1, 0.6 mol), 1,3-divinylbenzene (crosslinking agent M2, 1.0 mol) and N,N-dimethylacetamide (polar solvent, total volume 1 L) to the reactor and mix them evenly under stirring at 55 °C and 350 rpm;
[0058] (2) After passing nitrogen gas, add azobisisobutyronitrile (initiator, 0.03 mol), and heat to 105 °C for 14 h;
[0059] (3) Filter, wash with ethanol, and dry at 70 °C for 22 h to obtain a bromine-containing porous polymer precursor;
[0060] (4) Take 10 g of the precursor sample, disperse it in 90 mL of ethanol, add 2.2 g of 1,4-diazabicyclo[2.2.2]octane, and reflux for 21 h;
[0061] (5) Filter, wash with ethyl acetate, and dry at 88 °C for 20 h to obtain polymeric ionic liquid product E.
[0062] Product E has a BET specific surface area of 780 m²·g⁻¹ and a total pore volume of 0.92 cm³ / g, exhibiting a well-developed mesoporous and macroporous structure. At 25 °C, the saturated adsorption capacities for p-phenol, p-cresol, and 2,6-xylenol are 538 mg·g⁻¹, 445 mg·g⁻¹, and 428 mg·g⁻¹, respectively.
[0063] Example 6
[0064] (1) Add 4-vinylbenzyl chloride (monomer M1, 0.9 mol), 1,4-divinylbenzene (crosslinking agent M2, 0.9 mol) and ethyl acetate (polar solvent, total volume 1 L) to the reactor and mix them evenly under stirring at 40 °C and 500 rpm;
[0065] (2) After purging with nitrogen for 30 min, add azobisisobutyronitrile (initiator, 0.045 mol), and heat to 85 °C for 36 h.
[0066] (3) After the reaction was completed, the product was filtered, washed with ethanol until clear, and dried at 75 °C for 20 h to obtain a chlorine-containing porous polymer precursor.
[0067] (4) Take 10 g of the precursor sample, disperse it in 80 mL of ethanol, add 1.6 g of 1,4-diazabicyclo[2.2.2]octane, and reflux for 22 h;
[0068] (5) The solid was collected by filtration, washed with ethyl acetate, and dried at 92 °C for 18 h to obtain the polymeric ionic liquid product F.
[0069] Characterization revealed that product F has a BET specific surface area of 480 m²·g⁻¹, with pore size distribution concentrated in the mesopore range. At 25 °C, its saturated adsorption capacity for p-phenol is 495 mg·g⁻¹, for o-cresol it is 408 mg·g⁻¹, and for 2,4-xylenol it is 395 mg·g⁻¹.
[0070] Example 7
[0071] (1) Add 4-vinylbenzyl bromide (monomer M1, 0.5 mol), 1,4-divinylbenzene (crosslinking agent M2, 1.0 mol) and tetrahydrofuran (polar solvent, total volume 1 L) to the reactor and mix them evenly under stirring at 60 ℃ and 400 rpm;
[0072] (2) After purging with nitrogen, add benzoyl peroxide (initiator, 0.05 mol) and heat to 100 °C for 24 h.
[0073] (3) Filter, wash with ethanol, and dry at 70 °C for 24 h to obtain a high cross-linked bromine-containing polymer precursor;
[0074] (4) Take 10 g of the precursor sample, disperse it in 120 mL of ethanol, add 3.0 g of 1,4-diazabicyclo[2.2.2]octane, and reflux for 24 h;
[0075] (5) The solid was collected by filtration, washed with ethyl acetate, and dried at 92 °C for 18 h to obtain polymeric ionic liquid product G.
[0076] Product G has a BET specific surface area of 710 m²·g⁻¹, with pore size distribution concentrated in the mesopore range. At 25 °C, the saturated adsorption capacities for p-phenol, m-cresol, and 3,4-xylenol are 515 mg·g⁻¹, 425 mg·g⁻¹, and 410 mg·g⁻¹, respectively.
[0077] Comparative Example 1
[0078] Industrial-grade commercial granular activated carbon (particle size 20-40 mesh) was selected as the control adsorbent, and its adsorption performance was tested under the same conditions as in Example 1.
[0079] Take 20 mg of commercial activated carbon and add 50 mL of phenol solution (500 mg / L), 50 mL of cresol solution (500 mg / L), and 50 mL of xylenol solution (500 mg / L). Shake at room temperature until saturation. Determine the concentration of each phenol in the solutions after adsorption using UV-Vis spectrophotometry and calculate the saturated adsorption capacity.
[0080] Test results: The saturated adsorption capacity of commercial activated carbon for phenol was 285 mg·g⁻¹, for p-cresol it was 210 mg·g⁻¹, and for xylenol it was 195 mg·g⁻¹. Its BET specific surface area was 850 m²·g⁻¹, but due to the lack of targeted active sites and a matching hierarchical porous structure, its adsorption capacity for phenols was far lower than that of the polymeric ionic liquid of this invention.
[0081] Comparative Example 2
[0082] Following the preparation steps of Example 1, except for omitting the quaternization reaction in step (4), a porous polymer without quaternary ammonium salt groups was prepared (denoted as product H). The specific steps are as follows:
[0083] (1) Add 4-vinylbenzyl chloride (monomer M1, 0.5 mol), 1,4-divinylbenzene (crosslinking agent M2, 0.5 mol) and N,N-dimethylformamide (polar solvent, total volume 1 L) to the reactor and mix them evenly under stirring conditions of 40 °C and 500 rpm;
[0084] (2) Nitrogen gas was introduced into the mixture for 30 min, and azobisisobutyronitrile (initiator, 0.025 mol) was added. The mixture was heated to 100 °C and reacted for 18 h.
[0085] (3) After the reaction is complete, the solid product is collected by filtration, washed with ethanol until the filtrate is clear, and dried at 70 °C for 18 h to obtain the unquaternized porous polymer product H.
[0086] Product H was characterized and its adsorption performance was tested under the same conditions as in Example 1. The results showed that Product H had a BET specific surface area of 920 m²·g⁻¹; its saturated adsorption capacity for phenol was 150 mg·g⁻¹, for cresol it was 120 mg·g⁻¹, and for xylenol it was 110 mg·g⁻¹. Due to the lack of specific interaction between the quaternary ammonium salt group and phenol molecules, its adsorption capacity was only 1 / 3 to 1 / 4 of that of the polymeric ionic liquid of this invention, demonstrating that the quaternary ammonium salt group is the key active site for achieving efficient adsorption.
[0087] Comparative Example 3
[0088] XAD-4 macroporous adsorption resin, commonly used in industry, was selected as a comparison, and its adsorption performance was tested according to the test conditions of Example 1:
[0089] 20 mg of XAD-4 resin was added to each of the three phenolic solutions mentioned above, and the mixture was shaken at room temperature until saturation. The test results showed that the saturated adsorption capacity of XAD-4 resin for phenol was 190 mg·g⁻¹, for p-cresol it was 165 mg·g⁻¹, and for xylenol it was 155 mg·g⁻¹. Its BET specific surface area was 780 m²·g⁻¹, but because it relies solely on hydrophobic interactions to adsorb phenols and lacks specific interactions, its adsorption capacity and selectivity are far lower than those of the polymeric ionic liquid of this invention.
[0090] Comparative Example 4
[0091] Following the preparation steps of Example 1, the 1,4-diazabicyclo[2.2.2]octane in step (4) was replaced with triethylamine to prepare polyionic liquid product I. The specific steps are as follows:
[0092] (1)-(3) are the same as steps (1)-(3) in Example 1, to obtain a chlorine-containing porous polymer precursor;
[0093] (4) Disperse 10 g of the above precursor in 100 mL of ethanol, add 3 g of triethylamine, and reflux for 22 h;
[0094] (5) After the reaction is complete, the solid product is collected by filtration, washed with ethyl acetate until the filtrate is clear, and dried at 90 °C for 18 h to obtain product I.
[0095] Characterization and adsorption tests were performed on Product I. The results showed that Product I had a BET specific surface area of 550 m²·g⁻¹, a saturated adsorption capacity of 310 mg·g⁻¹ for phenol, 250 mg·g⁻¹ for cresol, and 230 mg·g⁻¹ for xylenol. Because the triethylamine-derived quaternary ammonium salt group has a simple spatial structure, its hydrogen bonding and ion-dipole interactions with phenol molecules are weaker than those of the quaternary ammonium salt group derived from 1,4-diazabicyclo[2.2.2]octane, leading to a significant decrease in adsorption performance. This demonstrates that the quaternization reagent selected in this invention is one of the key factors in improving adsorption performance.
[0096] 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 polyionic liquid for phenol adsorption, characterized by, The polymeric ionic liquid, which can be used to extract phenolic compounds from coal tar, is a polymeric ionic liquid formed by chemical bonding of a porous polymer framework of styrene and stilbene with quaternary ammonium salt groups, and has the structure shown in Formula I: Formula I.
2. Polyionic liquid for phenol adsorption according to claim 1, characterized by the fact that, The polyionic liquid has micropore, mesopore and macropore structures, and the BET specific surface area is 400-800 m 2 ・g -1 .
3. The polyionic liquid for phenol adsorption according to claim 1, wherein The quaternary ammonium salt group is a quaternary ammonium salt formed by halogen and 1,4-diazabicyclo[2.2.2]octane.
4. The polyionic liquid for phenol adsorption according to claim 1, wherein The saturated adsorption amount of the polyionic liquid to phenol, cresol and dimethylphenol at room temperature is greater than 500 mg·g -1 , 400 mg·g -1 and 400 mg·g -1 .
5. The polyionic liquid for phenol adsorption according to claim 1, wherein The preparation method of the polyionic liquid is as follows: (1) Stir monomer M1, crosslinking agent M2 and polar solvent at 300-800 rpm and mix them thoroughly at 40-60 ℃, wherein the molar ratio of monomer M1 to crosslinking agent M2 is 0.5-2:1 and the concentration of monomer M1 is 0.5-2 mol / L; (2) Nitrogen gas is introduced to protect the above (1), then an initiator is added, and then the temperature is raised to 80-120 °C and reacted for 12-24 h, wherein the molar ratio of catalyst to monomer M1 is 0.01-0.1:1; (3) The solid product obtained by filtration separation step (2) is washed with ethanol until the filtrate becomes clear, and then dried at 60-80 °C for 12-24 h; (4) Disperse the product of step (3) in ethanol, then add 1,4-diazabicyclo[2.2.2]octane and reflux for 20-24 h, wherein the mass ratio of the product of step (3) to 1,4-diazabicyclo[2.2.2]octane is 4-10:1, and the mass ratio of ethanol to the product of step (3) is 5-10:1; (5) After the reaction is complete, the solid product is separated by filtration and washed with ethyl acetate until the filtrate is clear. Then, it is dried in an oven at 80-100 °C for 12-24 h to obtain the polymeric ionic liquid.
6. The method for preparing polymeric ionic liquid according to claim 5, characterized in that: The monomer M1 is one or more of 4-vinylbenzyl chloride and 4-vinylbenzyl bromide.
7. The method for preparing polymeric ionic liquid according to claim 5, characterized in that: The crosslinking agent M2 is one or more of 1,4-divinylbenzene, 1,3-divinylbenzene, and 1,2-divinylbenzene.
8. The method for preparing polymeric ionic liquid according to claim 5, characterized in that: The polar solvent is one of ethyl acetate, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.
9. The method for preparing polymeric ionic liquid according to claim 5, characterized in that: The initiator is one of azobisisobutyronitrile, azobisisoheptane, benzoyl peroxide, and lauroyl peroxide.