A polyionic liquid porous organic polymer and a preparation method and application thereof

Abstract

The application discloses a kind of polyionic liquid porous organic polymer and its preparation method and application, the polyionic liquid porous organic polymer is obtained by graft copolymerization under the induction of polymerization initiator by aromatic porous organic polymer (porous organic polymers, POPs) with unsaturated side chain group and the cation group of vinyl ionic liquid containing imidazolium salt.This application mainly uses copolymerization method to prepare polyionic liquid porous organic polymer adsorption material, on this basis, by blending adsorption material with polymer material and granulating forming phase inversion, granulation or film forming is realized by electrospinning.The composite microsphere particle or nanofiber membrane of the application can realize the efficient selective adsorption of radionuclide at very low concentration, which is helpful for the rapid storage of low concentration radioactive substances, and has important value in emergency disposal of sudden radioactive substance leakage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular materials and radioactive wastewater treatment, and particularly relates to a poly ionic liquid porous organic polymer and a preparation method and application thereof. BACKGROUND

[0002] The pollution of radioactive substances to the environment has attracted widespread attention of countries around the world. Radioactive nuclides contained in nuclear contaminated water can enter the human body through the food chain and be enriched, and then affect human DNA, induce health problems such as deformity, limb disability, and cell canceration. Since the radioactive nuclides have a long half-life and good water-soluble characteristics, their radiation threat often enters the environment through water channels and lasts for hundreds or even tens of thousands of years, which will undoubtedly cause unpredictable damage and harm to human health and reproduction.

[0003] The adsorption of radioactive nuclides in water to achieve water purification is an effective means to solve the above problems. However, since the radioactive nuclides often exist in water at very low concentrations, the ion competition of the nuclides is too strong, and most of the nuclides captured by the adsorbent will be exchanged by other anions, so that high-efficiency removal cannot be achieved. Therefore, it is essential to develop an adsorbent that can have high-efficiency selective adsorption performance for radioactive nuclides at very low concentrations. At the same time, since the adsorbent is mostly in powder form, it poses a challenge to the recovery and reuse of the adsorbent, and therefore, effective loading of the adsorbent to achieve multiple reuse has outstanding application value. SUMMARY

[0004] The present application aims at the technical defects in the prior art, and provides a poly ionic liquid porous organic polymer.

[0005] Another object of the present application is to provide a composite microsphere particle based on the poly ionic liquid porous organic polymer.

[0006] Another object of the present application is to provide a nanofiber membrane based on the poly ionic liquid porous organic polymer.

[0007] Another object of the present application is to provide the application of the composite microsphere particle in the adsorption and sequestration of radioactive substances.

[0008] Another object of the present application is to provide the application of the nanofiber membrane in the adsorption and sequestration of radioactive substances.

[0009] The technical scheme adopted to achieve the object of the present application is as follows:

[0010] A poly ionic liquid porous organic polymer is obtained by graft copolymerization of a porous aromatic organic polymer (POPs) with unsaturated side chain groups and a vinyl ionic liquid containing cationic groups of imidazolium salt under the induction of a polymerization initiator.

[0011] In the above technical solution, the polymerization initiator is azobisisobutyronitrile, azobisisoheptyl nitrile, azobisisopentyl nitrile or 1,1'-azocyanocyclohexane, and the graft copolymerization is carried out in a solvent methanol solution.

[0012] In the above technical solution, the porous aromatic organic polymer with unsaturated side chain groups is obtained by cross-coupling of a double-edge structural unit and a linking unit, and the structural formula of the double-edge structural unit is as follows:

[0013]

[0014] In the above technical solution, the porous aromatic organic polymer with unsaturated side chain groups is obtained by cross-coupling of a double-edge structural unit and a linking unit, and the structural formula of the double-edge structural unit is as follows:

[0015] The structural formula of the linking unit is as follows:

[0016]

[0017] In the above technical solution, the porous aromatic organic polymer with unsaturated side chain groups is obtained by cross-coupling of a double-edge structural unit and a linking unit, and the structural formula of the double-edge structural unit is as follows: -C≡CH

[0018] In the above technical solution, the preparation method of the poly ionic liquid porous organic polymer comprises the following steps:

[0019] Step 1, mix the porous aromatic organic polymer with unsaturated side chain groups, the vinyl ionic liquid containing cationic groups of imidazolium salt, the methanol solution and azobisisobutyronitrile, heat and stir under nitrogen atmosphere for 24-72h;

[0020] Step 2, add azobisisobutyronitrile with the same mass as that of step 1 to the reaction system obtained in step 1, continue to heat and stir for 24-72h, cool to room temperature after the reaction is completed, separate the solid product, wash with methanol, and obtain the poly ionic liquid porous organic polymer.

[0021] In the above technical solution, in step 1, the mass fraction of the porous aromatic organic polymer with unsaturated side chain groups, the mass fraction of the vinyl ionic liquid containing cationic groups of imidazolium salt, the volume fraction of methanol and the mass fraction of azobisisobutyronitrile are in the ratio of (200-300):(500-1500):(20-30):(100-125), the unit of the volume fraction is mL, and the unit of the mass fraction is mg.

[0022] In the above technical solution, in the step 1 and the step 2, the temperature of the heating and stirring is 65-75 DEG C.

[0023] Another aspect of the present application also includes a composite microsphere particle, a polyionic liquid porous organic polymer as an adsorption material, and a polymer material combined by granulation forming to obtain the composite microsphere particle.

[0024] In the above technical solution, the average particle size of the composite microsphere particle is 5-10 mm, the composite microsphere particle is a high-hardness sphere, the shrinkage rate after drying is less than 0.6%, and the composite microsphere particle is stable in an environment with a pH of 1-13.

[0025] In the above technical solution, the composite microsphere particle is prepared by the following steps:

[0026] Step 1, the polyionic liquid porous organic polymer, the polymer material and N, N-dimethylformamide are mixed, heated and stirred until completely dissolved to obtain a polymer solution;

[0027] Step 2, the polymer solution obtained in step 1 is added with polyethylene glycol and stirred uniformly, and then dropped into a coagulation bath for phase inversion to obtain the composite microsphere particle.

[0028] In the above technical solution, in the step 1, the mass ratio of the adsorption material, N, N-dimethylformamide and the polymer material is (4-6):(60-70):(15-20).

[0029] In the above technical solution, in the step 1, the polymer material is polyether sulfone, polyvinylidene fluoride or polyacrylonitrile.

[0030] In the above technical solution, in the step 1, the temperature of the heating and stirring is 60-80 DEG C.

[0031] In the above technical solution, in the step 2, the coagulation bath is a water solution containing ethanol with a volume fraction of 20-50%.

[0032] Another aspect of the present application also includes a nanofiber membrane, a polyionic liquid porous organic polymer as an adsorption material, and a polymer material combined by electrospinning.

[0033] In the above technical solution, the average nanofiber diameter of the nanofiber membrane is 40-100 nm, the fibers in the nanofiber membrane are randomly stacked, the average porosity in the nanofiber membrane is greater than 50%, and the nanofiber membrane is stable in an environment with a pH of 1-13.

[0034] In the above technical solution, the nanofiber membrane is prepared by the following steps:

[0035] The polyionic liquid@porous organic polymer, polymer material and N,N-dimethylformamide are mixed, heated and stirred until completely dissolved to obtain a polymer solution, and the polymer solution is electrostatically spun to obtain a nanofiber membrane.

[0036] In the above technical solution, the electrospinning conditions are: voltage of 17-23 kV, distance between receiver and nozzle of 16-20 cm, propulsion speed of 0.8-1.1 mL / h, nozzle translation speed of 300-500 mm / min, and ambient humidity of 30-60%.

[0037] Another aspect of the present invention also includes the use of the composite microsphere particles in the adsorption and storage of radioactive substances.

[0038] Another aspect of the present invention also includes the use of the nanofiber membrane in the adsorption and storage of radioactive substances.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The present invention mainly adopts the copolymerization method to prepare the adsorption material. On this basis, the adsorption material is blended with the polymer material and granulated to form a phase transformation to achieve granulation or electrostatic spinning to achieve film formation. The composite microsphere particles or nanofiber membrane of the present invention can achieve efficient selective adsorption of radioactive nuclides at extremely low concentrations, and efficiently remove low-concentration anionic radionuclides (such as I – , IO3 – , TcO4 – , SeO3 – and SeO4 – etc.), and the treated solution meets the drinking water standard, which helps to quickly seal low-concentration radioactive substances and has important value in the emergency response to sudden radioactive substance leaks.

[0041] 2. The polyionic liquid@porous organic polymer prepared by the present invention exhibits excellent selective adsorption properties. The polyionic liquid@porous organic polymer is prepared by copolymerizing aromatic framework materials and ionic liquids in varying ratios. The electrospinning solution is prepared by blending polyionic liquid@porous organic polymers with polymers in varying ratios, and the granulation is prepared by blending polyionic liquid@porous organic polymers with polymers in varying ratios. The polyionic liquid@porous organic polymer exhibits excellent selective adsorption properties in dynamic adsorption tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is the synthesis route of the polyionic liquid@porous organic polymer in Example 1.

[0043] Figure 2Process schematic for composite microsphere particles of Example 1.

[0044] Figure 3 Selectivity and recycling performance graph for composite microsphere particles of Example 1.

[0045] Figure 4 Process schematic for nanofiber membrane of Example 2.

[0046] Figure 5 Selectivity and recycling performance graph for nanofiber membrane of Example 2. DETAILED DESCRIPTION

[0047] The present application will be further described by the following figures and specific examples. It should be understood that the specific examples described herein are intended to explain the present application and are not intended to limit the present application.

[0048] Example 1

[0049] A preparation method of a polyionic liquid@porous organic polymer, comprising the following steps:

[0050] As shown in Figure 1 Step 1, 250 mg of aromatic porous organic polymer with unsaturated side chain groups, 1000 mg of vinyl ionic liquid (bis-C2) containing imidazolium salt cationic groups, 30 mL of methanol solution and 125 mL of azobisisobutyronitrile were mixed, heated and stirred under nitrogen atmosphere at 70°C for 24 h;

[0051] The aromatic porous organic polymer with unsaturated side chain groups is obtained by cross-coupling of bilateral structure units and linking units; the structure formula of the bilateral structure unit is as follows:

[0052]

[0053] Among them,

[0054] The structure formula of the linking unit is as follows:

[0055]

[0056] Among them, R3 is -C=CH

[0057] Step 2, the same amount of azobisisobutyronitrile as in step 1 was added to the reaction system obtained in step 1, and the reaction was continued for 24 h, and then cooled to room temperature. The solid product was separated and washed with methanol to obtain a polyionic liquid@porous organic polymer;

[0058] A method for preparing composite microsphere particles based on the polyionic liquid@porous organic polymer comprises the following steps:

[0059] like Figure 2 As shown, the 6wt% polyionic liquid@porous organic polymer prepared above is stirred evenly with 20wt% polymer material as an adsorption material, and then added to 65wt% N,N-dimethylformamide (or the 6wt% polyionic liquid@porous organic polymer prepared above is stirred evenly with 65wt% N,N-dimethylformamide, and then 20wt% polymer material is added), heated and stirred at 60-80°C until completely dissolved to obtain a polymer solution, 9wt% polyethylene glycol is added to the polymer solution and stirred evenly, and then dropped into an aqueous solution containing ethanol with a volume fraction of 50% v / v% for granulation to obtain composite microsphere particles, wherein the polymer material is polyethersulfone.

[0060] like Figure 3 As shown, the composite microspheres obtained in Example 1 were tested for their adsorption performance, using a 50 ppb TcO₄⁻ solution as the feed solution. The results demonstrate that even in low-concentration feed solutions, the composite microspheres of this example achieve highly efficient TcO₄⁻ removal (>99%). Within a 10-minute operating period, the TcO₄⁻ concentration remained below 0.155 ppb, fully meeting the WHO drinking water guidelines. Even after five adsorption-desorption cycles (1500 mL), the composite microspheres of this example maintained a TcO₄⁻ removal rate exceeding 95.05%.

[0061] Example 2

[0062] A method for preparing a nanofiber membrane based on the polyionic liquid@porous organic polymer comprises the following steps:

[0063] like Figure 4 As shown, the 6wt% polyionic liquid @ porous organic polymer obtained in Example 1 is stirred evenly with 20wt% polymer material as an adsorbent material, and then added to 74wt% N,N-dimethylformamide (or the 6wt% polyionic liquid @ porous organic polymer prepared above is stirred evenly with 74wt% N,N-dimethylformamide, and then 20wt% polymer material is added), heated and stirred at 60-80°C until completely dissolved to obtain a polymer solution, and then the polymer solution is sucked into a syringe and clamped on a propeller for electrospinning. After the polymer solution is completely injected, the electrospinning is stopped immediately, and the nanofiber membrane is naturally dried at room temperature to obtain a nanofiber membrane, wherein the polymer material is polyethersulfone; the electrospinning conditions are: voltage of 20kV, distance between the receiver and the nozzle of 18cm, propulsion speed of 0.8mL / h, nozzle translation speed of 500mm / min, and ambient humidity of 50%.

[0064] like Figure 5 As shown, the adsorption performance of the nanofiber membrane obtained in this embodiment was tested, and 50ppb of TcO4 - The results show that even in low concentration feed solution, nanofiber membrane can achieve TcO4 - High efficiency removal (>99%), TcO4 - The concentration remained below 0.13 ppb, which fully meets the WHO drinking water guidelines (<0.155 ppb). Therefore, the nanofiber membrane can still maintain more than 95.14% TcO4 after five adsorption-desorption cycles (1500 mL). - Removal rate.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A polyionic liquid@porous organic polymer, characterized in that, Graft copolymerization of aromatic porous organic polymers (POPs) with unsaturated side chain groups and vinyl ionic liquid containing cationic groups of imidazolium salt under the induction of a polymerization initiator to obtain a polyionic liquid@porous organic polymer (PIL@POP); The aromatic porous organic polymer with unsaturated side chain groups is obtained by cross-coupling of a bilateral structure unit and a linking unit, and the structure of the bilateral structure unit is as follows: ， wherein ; The structure of the linking unit is as follows: wherein ; The ratio of the mass fraction of the aromatic porous organic polymer with unsaturated side chain groups to the mass fraction of the vinyl ionic liquid containing cationic groups of imidazolium salt is (200-300):(500-1500).

2. The polyionic liquid@porous organic polymer according to claim 1, wherein The polymerization initiator is azobisisobutyronitrile, azobisisoheptyl nitrile, azobisisopentyl nitrile or 1,1'-azobis-cyanocyclohexane, and the graft copolymerization is carried out in a methanol solution.

3. The polyionic liquid@porous organic polymer of claim 1, wherein The preparation method of the polyionic liquid@porous organic polymer comprises the following steps: Step 1, mix the aromatic porous organic polymer with unsaturated side chain groups, the vinyl ionic liquid containing cationic groups of imidazolium salt, a methanol solution and azobisisobutyronitrile, heat and stir for 24-72 hours under a nitrogen atmosphere, the temperature of the heating and stirring is 65-75°C, wherein the ratio of the mass fraction of the aromatic porous organic polymer with unsaturated side chain groups, the mass fraction of the vinyl ionic liquid containing cationic groups of imidazolium salt, the volume fraction of methanol and the mass fraction of azobisisobutyronitrile is (200-300):(500-1500):(20-30):(100-125), the unit of the volume fraction is mL, and the unit of the mass fraction is mg; Step 2, add azobisisobutyronitrile with the same mass as that in step 1 to the reaction system obtained in step 1, continue to heat and stir for 24-72 hours, the temperature of the heating and stirring is 65-75°C, cool to room temperature after the reaction is completed, separate the solid product, wash with methanol, and obtain the polyionic liquid@porous organic polymer.

4. A composite microsphere particle, characterized by, The polyionic liquid@porous organic polymer according to any one of claims 1-3 is used as an adsorbent material, is combined with a polymer material by granulation molding to obtain a composite microsphere particle, wherein the average particle size of the composite microsphere particle is 5-10 mm, the composite microsphere particle is a high-hardness sphere, the shrinkage rate after drying is less than 0.6%, and the composite microsphere particle is stable in an environment with a pH of 1-13.

5. The composite microsphere particle of claim 4, wherein, Preparation is carried out by the following steps: Step 1, mix the polyionic liquid@porous organic polymer, a polymer material and N,N-dimethylformamide, heat and stir until completely dissolved to obtain a polymer solution, wherein the polymer material is polyether sulfone, polyvinylidene fluoride or polyacrylonitrile, and the mass ratio of the adsorbent material, N,N-dimethylformamide and the polymer material is (4-6):(60-80):(15-20); Step 2, add polyethylene glycol to the polymer solution obtained in step 1 and stir uniformly, drop into a coagulation bath to perform phase inversion to obtain a composite microsphere particle, and the coagulation bath is a water solution containing ethanol with a volume fraction of 20-50%.

6. A nanofiber membrane characterized by, The polyionic liquid porous organic polymer according to any one of claims 1-3 is used as an adsorption material, and a polymer material is combined by electrospinning, wherein the average nanofiber diameter of the nanofiber membrane is 40-100 nm, the fibers in the nanofiber membrane are randomly stacked, the average porosity in the nanofiber membrane is >50%, and the nanofiber membrane is stable in an environment with a pH of 1-13.

7. The nanofiber membrane of claim 6, wherein, Preparation is carried out by the following steps: The polyionic liquid porous organic polymer, the polymer material and N,N-dimethylformamide are mixed, heated and stirred until completely dissolved to obtain a polymer solution, and the polymer solution is electrospun to obtain a nanofiber membrane.

8. The nanofiber membrane of claim 7, wherein, The electrospinning conditions are as follows: the voltage is 17-23 kV, the distance between the receiver and the nozzle is 16-20 cm, the pushing speed is 0.8-1.1 mL / h, the nozzle translation speed is 300-500 mm / min, and the ambient humidity is 30-60%.

9. Use of the composite microsphere particles according to claim 4 or 5 in the adsorption and sequestration of radioactive substances.

10. Use of the nanofiber membrane according to claim 6 or 7 in the adsorption and sequestration of radioactive substances.

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