Polymer composite adsorbent, synthetic method and method for separating xylene isomer

Abstract

The invention discloses a polymer composite adsorbent, a synthesis method and a method for separating xylene isomers. According to the molecular structure difference of xylene isomers, a 1-aminopyrene polymer composite adsorbent material is designed and synthesized, water is used as a medium to disperse the xylene isomers, and the xylene isomers are separated through multi-stage adsorption-desorption by utilizing the difference of acting force between the xylene isomers and polymer units. By adopting the method to separate p-xylene (PX), m-xylene (MX) and o-xylene (OX) according to the ratio of 1 / 1 / 1, OX with the purity higher than 99.0% (gas chromatography) can be obtained, MX with the purity higher than 98.5% (gas chromatography) can be obtained by separating PX / MX according to the ratio of 1 / 1, and the method has the advantage of low energy consumption.

Description

Technical Field

[0001] The present invention relates to materials and methods for separating xylene isomers. Background Art

[0002] Xylene is a very important chemical raw material, which is widely used in coatings, dyes, medicines, explosives and pesticides. The physical and chemical properties of xylene isomers p-xylene, m-xylene and o-xylene are very similar, and their boiling points are very close. At present, the industry mainly uses distillation, crystallization and adsorption methods to separate xylene isomers, which consumes a lot of energy and has low efficiency.

[0003] In recent years, various new solid adsorbents, such as MFI molecular sieves, molecular crystals, metal complexes, organic cages, metal-organic cages, porous coordination polymers (PCPs), metal-organic frameworks (MOFs), microporous organic polymers (MOPs), and switchable adsorbent materials, have been studied for the separation of xylene isomers. Most of these materials and separation methods are based on molecular recognition or screening based on temperature-dependent adsorption, and the separation process consumes a lot of energy.

[0004] New adsorbent materials for separating xylene isomers usually involve interactions between functional groups within the material and xylene molecules, and the selectivity of isomers is affected by different molecular sizes and interaction strengths. Therefore, a polymer adsorbent containing large π-conjugated system units can be designed to improve the adsorption capacity of xylene through π-π interactions. At the same time, the different relative positions of the two methyl groups in the xylene isomers and the different interaction strengths between the two side groups of the polymer unit and the two methyl groups are utilized to produce the selective adsorption of xylene isomers by the adsorbent, and the separation of xylene isomers is achieved by repeatedly adsorbing and desorbing multiple times and amplifying the small differences in adsorption capacity.

[0005] References:

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[0015]

[10] S.Q. Wang, et al., Angew. Chem. Int. Ed. 2019, 58, 6630. Summary of the Invention

[0016] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a polymer composite adsorbent and a synthesis method, and a method for using the polymer composite adsorbent and the composite adsorbent to separate xylene isomers.

[0017] In the first aspect, the present invention provides a polymer composite adsorbent, which is a composite of 1-aminopyrene polymer and supporting electrolyte, wherein the supporting electrolyte is 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF 4 ] or 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF 6 ].

[0018] As a preferred embodiment of the first aspect, the supporting electrolyte is 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM] [BF 4 ], the degree of polymerization of 1-aminopyrene in the 1-aminopyrene polymer is 14 to 130.

[0019] As a preferred embodiment of the first aspect, the supporting electrolyte is 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF 6 ], the degree of polymerization of 1-aminopyrene in the 1-aminopyrene polymer is 23 to 2790.

[0020] In a second aspect, the present invention provides a method for synthesizing a polymer composite adsorbent, wherein 1-aminopyrene is added as a raw material into an electrolytic cell with an anode and a cathode, and 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM] [BF 4 ] or 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF 6 ] as a supporting electrolyte, an electrochemical polymerization reaction was carried out in an organic solvent at a constant potential of 1.0 to 3.0 V to obtain a supporting electrolyte-doped 1-aminopyrene polymer.

[0021] As a preferred embodiment of the above second aspect, the electrolytic cell is preferably a single-cell electrolytic cell.

[0022] As a preference for the second aspect above, the anode is preferably a graphite anode.

[0023] As a preference for the second aspect above, the cathode is preferably a graphite cathode.

[0024] As a preference in the above second aspect, the organic solvent is preferably acetonitrile.

[0025] In a third aspect, the present invention provides an adsorbent for separating xylene isomers made from the polymer composite adsorbent as described in any one of the first aspects above.

[0026] In a fourth aspect, the present invention provides a method for separating xylene isomers, which utilizes the polymer composite adsorbent as described in any one of the first aspects to perform adsorption separation on an aqueous dispersion of xylene isomers.

[0027] The present invention designs and synthesizes a polymer composite adsorbent material based on the molecular structure difference of xylene isomers. The adsorbent uses water as a medium to disperse the xylene isomers, utilizes the difference in the force between the xylene isomers and the polymer unit, and separates the xylene isomers through multi-stage adsorption-desorption. The polymer composite adsorbent provided by the present invention can be synthesized by an electrochemical method, with low raw material cost and simple synthesis process, and the separation method based on the adsorbent has the advantages of low energy consumption in the separation process and high purity of the obtained single xylene isomer. In particular, the polymer composite adsorbent is used to separate p-xylene (PX) / m-xylene (MX) / o-xylene (OX) = 1 / 1 / 1, and OX with a purity higher than 99.0% (gas chromatography analysis) can be obtained, and MX with a purity higher than 98.5% (gas chromatography analysis) can be obtained by separating PX / MX = 1 / 1. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 .[BMIM][BF 4 ] and PAP / [BMIM][BF 4 ]of 1 HNMR comparison chart (proving PAP / [BMIM][BF 4 ] structure of the complex);

[0029] Figure 2 .[BMIM][PF 6 ] and PAP / [BMIM][PF 6 ]of 1 HNMR comparison chart (proving PAP / [BMIM][PF 6 ] structure of the complex);

[0030] Figure 3 . SEM images of two compounds, a) and b) are PAP / [BMIM][BF 4 ], c) and d) are SEM images of PAP / [BMIM][PF 6 ]SEM images;

[0031] Figure 4 .TEM images of two compounds, where a) is PAP / [BMIM][BF 4 ], b) TEM image of PAP / [BMIM][PF 6 ]TEM image;

[0032] Figure 5.Single crystal XRD structure of 1-aminopyrene dimer;

[0033] Figure 6 .PAP / [BMIM][BF 4 ] Before and after adsorption of xylene 1 HNMR comparison spectra;

[0034] Figure 7 .PAP / [BMIM][PF 6 ] Before and after adsorption of xylene 1 HNMR comparison spectra;

[0035] Figure 8 .PAP / [BMIM][BF 4 ] Gas chromatogram of separation of three components of xylene isomers;

[0036] Fig. 9 .PAP / [BMIM][BF 4 ] Gas chromatogram of separation of two component xylene isomers;

[0037] Fig.10 .PAP / [BMIM][PF 6 ]Gas chromatogram of separation of three components of xylene isomers. DETAILED DESCRIPTION

[0038] The present invention is further described and illustrated below in conjunction with the accompanying drawings and specific embodiments.

[0039] The present invention provides a polymer composite adsorbent, which is a composite formed by doping 1-aminopyrene polymer (1-aminopyrene polymer, PAP) with a supporting electrolyte, wherein the supporting electrolyte can be selected to have different X groups (BF 4 PF 6 ) are two ionic liquids, namely 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM] [BF 4 ] or 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF 6 ], the structural formulas of PAP and two supporting electrolytes are as follows:

[0040]

[0041] The composite adsorbents corresponding to the two ionic liquids are denoted as PAP / [BMIM][BF 4 ] and PAP / [BMIM][PF 6 ], the structural formula of the complex can be expressed as Formula I:

[0042]

[0043] In Formula I, the dotted line represents the electrical attraction between PAP and the supporting electrolyte formed by π-π interaction during the electrochemical synthesis process, thereby achieving doping between the two in a certain ratio.

[0044] The adsorbent utilizes the different relative positions of the two methyl groups in xylene isomers and the different interaction strengths between the two side groups of the polymer unit and the two methyl groups, thereby producing selective adsorption of xylene isomers by the adsorbent, and achieves the separation of xylene isomers by repeated adsorption-desorption and amplifying the slight differences in adsorption capacity.

[0045] In the polymer composite adsorbent, PAP is used as the adsorbent for separating xylene isomers. The distances between the two methyl groups of p-xylene (PX), m-xylene (MX) and o-xylene (OX) are and In the polymer composite adsorbent, when 1-aminopyrene monomer is polymerized along its 1,6 position axial direction, a "-NH-pyrene-NH-" unit is formed, which has a large π-conjugated system and two adjacent amino groups with a spacing of Each unit can be connected by π-π interactions and different strengths of -CH 3 The van der Waals interaction between - and -NH- forms a force field to identify and distinguish different xylene isomers, that is, there are differences in the interactions between the three xylene isomers PX, MX, OX and -NH-pyrene-NH- units. If water is used as a dispersion carrier, the xylene isomers and units interact through multiple adsorption-desorption interactions, continuously amplifying the differences in adsorption capacity and the slight differences in diffusion rates, thereby achieving separation at room temperature. Therefore, compared with those temperature-dependent adsorbents based on the interactions between functional groups and xylene molecules and the differences in the size of xylene molecules, this liquid-solid phase separation of xylene isomers has the advantage of low energy consumption.

[0046] The present invention also provides a method for synthesizing a polymer composite adsorbent, wherein 1-aminopyrene is added as a raw material into an electrolytic cell with an anode and a cathode, and 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM] [BF 4 ] or 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF 6 ] as a supporting electrolyte, an electrochemical polymerization reaction was carried out in an organic solvent at a constant potential of 1.0 to 3.0 V to obtain a supporting electrolyte-doped 1-aminopyrene polymer.

[0047] In the above synthesis method, the electrolytic cell is preferably a single-cell electrolytic cell, the anode is preferably a graphite anode, the cathode is preferably a graphite cathode, and the organic solvent is preferably acetonitrile.

[0048] The polymer composite adsorbent can be used as an adsorbent for separating xylene isomers. Specifically, the method for separating xylene isomers is: using the polymer composite adsorbent to perform adsorption separation on an aqueous dispersion of xylene isomers. In practical applications, the polymer composite adsorbent can be made into a multi-stage series adsorption unit, and the aqueous dispersion of xylene isomers is passed through each stage of adsorption unit in turn, and separation is achieved through multiple adsorption-desorption cycles to obtain a single high-purity xylene isomer.

[0049] The following examples will help to understand the present invention, but the protection scope of the present invention is not limited to the contents of the following examples: Example 1 Synthesis of 1-aminopyrene polymer composite adsorbent

[0050] In a 400 mL non-separated electrolytic cell equipped with a graphite anode and a graphite cathode, 1-aminopyrene (400 mg, 1.84 mmol), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ])(6mL, 0.22mmol) and 400mL of acetonitrile. The reactants were stirred at room temperature and electrolyzed at a constant voltage of 3.0V for 24h. During the reaction, thin layer chromatography was used to track the progress of the reaction (the volume ratio of the developing solvent was DCM:PE=2:1). After the reaction, the electrolyte was evaporated to dryness and washed with deionized water, transferred to a centrifuge tube, and the upper layer of liquid was removed by centrifugation to leave a black powdery solid. Wash with 80ml of acetonitrile, 80ml of tetrahydrofuran and 300ml of water in sequence, and centrifuge for 3 times. Finally, the supernatant was decanted by centrifugation, and the precipitate was separated and dried to constant weight to obtain 0.60g of black solid powder.

[0051] Elemental analysis (wt%) PAP / [BMIM][BF 4 ]:C 79.57H 4.08N 6.03.

[0052] Table 1. PAP / [BMIM][BF 4 ] Transmission electron microscopy X-ray spectroscopy (TEM-EDS) data

[0053]

[0054] TEM-EDS data prove that PAP / [BMIM][BF 4 ] contains [BMIM][BF 4 ].

[0055] [BMIM][BF 4 ] and PAP / [BMIM][BF 4 ]of 1 HNMR comparison chart (attached Figure 1 ) proves PAP / [BMIM][BF4 ] is a 1-aminopyrene polymer (PAP) and a supporting electrolyte [BMIM][BF 4 ] complex. PAP / [BMIM][BF 4 ] in [BMIM][BF 4 The mass percentage of ] is 19.0%. SEM picture (attached Figure 3 ) and TEM images (attached Figure 4 ) indicates that PAP / [BMIM][BF 4 ] is a porous layered structure.

[0056] The PAP / [BMIM][BF 4 The average molecular weight of the polymer in ] is 10675 g / mol, the lowest molecular weight is 3000 g / mol, the highest molecular weight is 28000 g / mol, and the monomer molecular weight is 215 g / mol. From this, PAP / [BMIM][BF 4 The degree of polymerization of PAP in the mixture is in the range of 14 to 130. 4 ] has a contact angle of 68°.

[0057] UV-Vis absorption spectroscopy was used to quantitatively analyze PAP / [BMIM][BF 4 ] The concentration change of single component aqueous solution of xylene isomers before and after adsorption was measured. PAP / [BMIM][BF 4 ]The saturated adsorption capacities of PX, MX and OX are 247.68 mg / g, 235.66 mg / g and 200.84 mg / g respectively. 4 ]There are differences in the adsorption capacity for PX, MX and OX.

[0058] Example 2 Synthesis of 1-aminopyrene polymer composite adsorbent

[0059] In a 150 mL non-separated electrolytic cell equipped with a 20×20×3 mm graphite anode and a graphite cathode, 1-aminopyrene (1.09 g, 5 mmol), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6])(4.55g, 3.3mL, 16mmol) and 120mL of acetonitrile. The reactants were stirred at room temperature and electrolyzed at a constant voltage of 3.0V for 24h. During the reaction, thin layer chromatography was used to track the progress of the reaction (the volume ratio of the developing solvent was DCM:PE=2:1). After the reaction, the electrolyte was evaporated to dryness and washed with deionized water. It was transferred to a centrifuge tube and the upper liquid was removed by centrifugation to leave a black powdery solid. Wash with 80mL of acetonitrile, 80mL of tetrahydrofuran and 300mL of water in turn, and the centrifugal cycle was repeated 3 times. Finally, the supernatant was decanted by centrifugation, and the precipitate was separated and dried to constant weight to obtain 0.71g of black solid powder. Elemental analysis (wt%) PAP / [BMIM][PF 6 ]:C 78.44H 4.35N5.69.

[0060] Table 2. PAP / [BMIM][PF 6 ] Transmission electron microscopy X-ray spectroscopy (TEM-EDS) data

[0061]

[0062] TEM-EDS data prove that PAP / [BMIM][PF 6 ] contains [BMIM][PF 6 ].

[0063] [BMIM][PF 6 ] and PAP / [BMIM][PF 6 ]of 1 HNMR comparison chart (attached Figure 1 ) proves PAP / [BMIM][PF 6 ] is a 1-aminopyrene polymer (PAP) and a supporting electrolyte [BMIM][PF 6 ] complex. PAP / [BMIM][PF 6 ] in [BMIM][PF 6 The mass percentage of ] is 16.7%. SEM picture (attached Figure 3 ) and TEM images (attached Figure 4 ) indicates PAP / [BMIM][PF 6 ] is a porous layered structure, which is similar to PAP / [BMIM][BF 4 ] Compared with conventional nanostructured carbon nanotubes, nanostructured carbon nanotubes have fewer pores and larger pore diameters.

[0064] The PAP / [BMIM][PF 6The average molecular weight of the polymer in ] is 127040 g / mol, the lowest molecular weight is 5000 g / mol, and the highest molecular weight is 600000 g / mol. The molecular weight of the monomer is 215 g / mol. From this, PAP / [BMIM][PF 6 The degree of polymerization of PAP in the mixture is in the range of 23 to 2790. 6 ] has a contact angle of 78°.

[0065] UV-Vis absorption spectroscopy was used to quantitatively analyze PAP / [BMIM][PF 6 ] The concentration change of single component aqueous solution of xylene isomers before and after adsorption was measured to obtain PAP / [BMIM][PF 6 ]The saturated adsorption capacities of PX, MX and OX are 167.54 mg / g, 154.93 mg / g and 127.89 mg / g respectively. 6 ] have different adsorption capacities for PX, MX, and OX, and are smaller than PAP / [BMIM][BF 4 ] for PX, MX, OX adsorption, that is, PAP / [BMIM][PF 6 ] has weaker adsorption capacity for xylene than PAP / [BMIM][BF 4 ].

[0066] Example 3 PAP / [BMIM][BF 4 ]Degradation reaction

[0067] By degrading the PAP / [BMIM][BF 4 ], and analyze the structure of the degradation product to verify the structure of the polymer. Weigh 226 mg PAP / [BMIM][BF 4 ] was dispersed in 200mL THF, stirred and mixed thoroughly, and then 0.05mL hydrazine hydrate was added dropwise and reacted for 3h. The reaction solution was analyzed by thin layer chromatography (developing solvent: DCM: PE = 2:1). After the reaction was completed, the reaction solution was rotary evaporated, 200ml water was added and ultrasonically stirred and mixed thoroughly, and then back-extracted with dichloromethane three times (200mL×3). After the organic phase was concentrated under reduced pressure, it was purified by silica gel column chromatography (DCM: PE = 2:1) to obtain 15mg 1-aminopyrene dimer as a yellow solid powder. Its structure was determined by single crystal XRD (attached Figure 5 ) confirmed, proving that the structure of 1-aminopyrene polymer (PAP) is the 1,6-polymerization of 1-aminopyrene monomers.

[0068] Example 4 PAP / [BMIM][BF 4 ] and PAP / [BMIM][PF6 ] Experiment on adsorption of xylene isomers

[0069] 20 mg of adsorbent PAP / [BMIM][BF 4 ] and PAP / [BMIM][PF 6 ] were added to aqueous solutions of OX, MX and PX (25ul xylene in 200ml water) respectively. The mixture was ultrasonically dispersed for 2 hours and allowed to stand for 2 hours to ensure that the adsorption process reached equilibrium. The filter cake was dried overnight and then dissolved and dispersed in deuterated DMSO to test 1 HNMR spectrum. Figure 6 PAP / [BMIM][BF 4 ] Before and after adsorption of xylene 1 HNMR comparison spectra show that PAP / [BMIM][BF 4 ] adsorbed xylene, of which 6.92-7.16ppm and 2.18-2.28ppm were the H signal peaks of xylene; Figure 7 PAP / [BMIM][PF 6 ] Before and after adsorption of xylene 1 HNMR comparison spectra show that PAP / [BMIM][PF 6 ] adsorbed xylene, among which 6.92-7.16ppm and 2.18-2.28ppm were the H signal peaks of xylene.

[0070] Example 5 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0071] Weigh 60mg PAP / [BMIM][BF 4 ] was added to a 100 mL round-bottom flask, and 60 mL of water was added. The mixture was stirred and ultrasonically dispersed for 30 min until the dispersion was a uniform black opaque liquid. A 5 mL syringe was used to extract PAP / [BMIM][BF 4 ] 5 mL of dispersion was injected into the filter head (0.22 μ), and the filtrate was water, PAP / [BMIM][BF 4 ] The filter cake remained in the filter head. 25uL PX, 25uL MX and 25uL OX were mixed with 5ml water and ultrasonically dispersed for 30min to obtain a PX / MX / OX (1 / 1 / 1) aqueous dispersion. The dispersion was injected into the prepared PAP / [BMIM][BF 4 ] filter head, and collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was PX / MX / OX=1 / 1.4 / 2.5 (as shown in the attached Figure 8 step 1).

[0072] Example 6 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0073] According to the operation of Example 5, the aqueous dispersion of PX / MX / OX=1 / 1.4 / 2.5 was injected into the PAP / [BMIM][BF 4 ] filter head, and collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was PX / MX / OX=1 / 1.6 / 3.6 (as shown in the attached Figure 8 step2).

[0074] Example 7 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0075] According to the operation of Example 5, the aqueous dispersion of PX / MX / OX=1 / 1.6 / 3.6 was injected into the PAP / [BMIM][BF 4 ] filter head, and collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was PX / MX / OX=1 / 1.9 / 5.6 (see attached Figure 8 step3).

[0076] Example 8 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0077] According to the operation of Example 5, the aqueous dispersion of PX / MX / OX=1 / 1.9 / 5.6 was injected into the PAP / [BMIM][BF 4 ] filter head, and collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was PX / MX / OX=1 / 2.6 / 11.5 (see attached Figure 8 step 4).

[0078] Example 9 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0079] According to the operation of Example 5, the aqueous dispersion of PX / MX / OX=1 / 2.6 / 11.5 was injected into the PAP / [BMIM][BF 4 ] filter head, collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was PX / MX / OX = 1 / 3.6 / 21 (see attached Figure 8 step5).

[0080] Example 10 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0081] According to the operation of Example 5, the aqueous dispersion of PX / MX / OX=1 / 3.6 / 21 was injected into the PAP / [BMIM][BF 4 ] filter head, and collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was PX / MX / OX=1 / 5 / 42 (as shown in the attached Figure 8 step 6).

[0082] Example 11 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0083] According to the operation of Example 5, the aqueous dispersion of PX / MX / OX=1 / 5 / 42 was injected into the PAP / [BMIM][BF 4 ] filter head, and collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was PX / MX / OX=1 / 7 / 96 (see attached Figure 8 step 7).

[0084] Example 12 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0085] According to the operation of Example 5, the aqueous dispersion of PX / MX / OX=1 / 7 / 96 was injected into the PAP / [BMIM][BF 4 ] filter head, collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was PX / MX / OX=0 / 1 / 23 (as shown in the attached Figure 8 step 8).

[0086] Example 13 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0087] According to the operation of Example 5, the aqueous dispersion of MX / OX=1 / 23 was injected into the PAP / [BMIM][BF 4 ] filter head, collect the filtrate. The filtrate is sampled and analyzed by gas chromatography. The ratio of xylene isomers is MX / OX=1 / 44 (as shown in the attached Figure 8 step 9).

[0088] Example 14 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0089] According to the operation of Example 5, the aqueous dispersion of MX / OX=1 / 44 was injected into the PAP / [BMIM][BF 4 ] filter head, and collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was MX / OX=1 / 104.3, and the purity of the obtained OX was greater than 99.0% (as shown in the attached Figure 8 step 10).

[0090] Thus, Examples 5 to 14 above were based on PAP / [BMIM][BF by multi-stage adsorption. 4 ]The differences in adsorption capacity and diffusion rate between MX and OX enable high-purity separation of OX in the mixed dispersion.

[0091] Example 15 PAP / [BMIM][BF 4 ]Separation of xylene isomers

[0092] According to the operation of Example 5, the aqueous dispersion of PX / MX = 1 / 1 was injected into the PAP / [BMIM][BF 4 ] and collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was PX / MX=1 / 1.6. Then, the above operation was repeated to separate the aqueous dispersion of xylene isomers. When the 10th time was performed, PX / MX=1 / 69.4 was obtained. The purity of the obtained MX was greater than 98.5% (as shown in the attached Fig. 9 step1-10).

[0093] Example 16 PAP / [BMIM][PF 6 ]Separation of xylene isomers

[0094] Weigh 60mg PAP / [BMIM][PF 6 ] was added to a 100 mL round-bottom flask, and 60 mL of water was added. The mixture was stirred and ultrasonically dispersed for 30 min until the dispersion was a uniform black opaque liquid. A 5 mL syringe was used to extract PAP / [BMIM][PF 6 ] 5mL of dispersion was injected into the filter head (0.22μ), and the filtrate was water, PAP / [BMIM][PF 6] The filter cake remained in the filter head. 25ul PX, 25ul MX and 25ul OX were mixed with 5ml water and ultrasonically dispersed for 30min to obtain a PX / MX / OX (1 / 1 / 1) aqueous dispersion. The dispersion was injected into the prepared PAP / [BMIM][PF 6 ] filter head, and collect the filtrate. The filtrate was sampled and analyzed by gas chromatography. The ratio of xylene isomers was PX / MX / OX=1 / 1.1 / 1.6 (see attached Fig.10 shown).

[0095] Example 17 PAP / [BMIM][BF 4 ] Regeneration and recycling for separation of xylene isomers

[0096] The PAP / [BMIM][BF 4 ] filter head for separating xylene isomers, each time 5 mL of deionized water was sucked into the filter head with a syringe, and the deionized water was pressed into the filter head to clean the filter head. The cycle was repeated 10 times. The absence of xylene isomers was checked by gas chromatograph to indicate that the filter head was clean. The aqueous dispersion of PX / MX / OX (1 / 1 / 1) was injected into the regenerated PAP / [BMIM][BF 4 ] filter head, and collect the filtrate. The filtrate is sampled and analyzed by gas chromatography for the ratio of xylene isomers. Repeat PAP / [BMIM][BF 4 ] The regeneration and separation of PX / MX / OX (1 / 1 / 1) was performed 5 times, and the ratio analysis results of the xylene isomers in the obtained filtrate were as follows:

[0097] Table 3. PAP / [BMIM][BF 4 ] Ratio of xylene isomers obtained by regeneration and separation of PX / MX / OX (1 / 1 / 1) cycle operation

[0098]

[0099] The results of the above-mentioned adsorbent separation of xylene isomers show that PAP / [BMIM][BF 4 ] performs better than PAP / [BMIM][PF 6 ], from the difference analysis of the saturated adsorption of three xylene isomers by two adsorbents, PAP / [BMIM][BF 4 ] are greater than PAP / [BMIM][PF 6 ], PAP / [BMIM][BF 4 ] has a strong adsorption effect on xylene; from the contact angle analysis, PAP / [BMIM][BF 4] is less than PAP / [BMIM][PF 6 ] is 78°, indicating that the xylene water dispersion is 4 ] has better diffusion than PAP / [BMIM][PF 6 ]; from SEM morphology analysis, PAP / [BMIM][BF 4 ] has better porosity than PAP / [BMIM][PF 6 ], therefore, with PAP / [BMIM][PF 6 ] compared with PAP / [BMIM][BF 4 ]The differences in the molecular structures of xylene isomers can be more effectively amplified through repeated adsorption-desorption. It has good performance in separating xylene isomers and can be recycled.

[0100] The above-described embodiment is only a preferred solution of the present invention, but it is not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A polymer composite adsorbent, characterized in that: The adsorbent is a composite formed by doping 1-aminopyrene polymer with a supporting electrolyte, wherein the supporting electrolyte is 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] or 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6].

2. The polymer composite adsorbent according to claim 1, characterized in that: The supporting electrolyte is 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4], and the polymerization degree of 1-aminopyrene in the 1-aminopyrene polymer is 14-130.

3. The polymer composite adsorbent according to claim 1, characterized in that: The supporting electrolyte is 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], and the polymerization degree of 1-aminopyrene in the 1-aminopyrene polymer is 23-2790.

4. A method for synthesizing a polymer composite adsorbent, characterized in that: 1-Aminopyrene is added as a raw material into an electrolytic cell with an anode and a cathode, and 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] or 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6] is added as a supporting electrolyte. An electrochemical polymerization reaction is carried out in an organic solvent at a constant potential of 1.0 to 3.0 V to obtain a supporting electrolyte-doped 1-aminopyrene polymer.

5. The synthesis method according to claim 4, characterized in that: The electrolytic cell is preferably a single-cell electrolytic cell.

6. The synthesis method according to claim 4, characterized in that: The anode is preferably a graphite anode.

7. The synthesis method according to claim 4, characterized in that: The cathode is preferably a graphite cathode.

8. The synthesis method according to claim 4, characterized in that: The organic solvent is preferably acetonitrile.

9. An adsorbent for separating xylene isomers made from the polymer composite adsorbent according to any one of claims 1 to 3.

10. A method for separating xylene isomers, characterized in that: The polymer composite adsorbent according to any one of claims 1 to 3 is used to perform adsorption separation on an aqueous dispersion of xylene isomers.

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