Three-dimensional cationic polymer, process for its preparation and use thereof

Abstract

The present application relates to the technical field of adsorbent, and provides a kind of three-dimensional cationic polymer and its preparation method and application.The three-dimensional cationic polymer provided by the present application is polymerized by tetra (4- (bromomethyl) phenyl) methane and 2,2',6,6'-tetramethyl-4,4'-bipyridine.The three-dimensional cationic polymer is prepared by Menschutkin reaction, and has high-density pyridinium salt units and a large number of hydrophobic alkyl on the interpenetrating skeleton.On the one hand, it improves the adsorption dynamics and adsorption selectivity of the material to perrhenate ions, thereby realizing high selectivity and ultrafast removal of perrhenate ions in water.On the one hand, it ensures that TMP-TBPM can still achieve fast and high-selectivity removal of perrhenate ions through ion exchange mechanism under strong acid or strong base conditions.The preparation method of the three-dimensional cationic polymer provided by the present application is simple and environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorbents, and in particular to a three-dimensional cationic polymer and a preparation method and application thereof. Background Art

[0002] Nuclear energy has an extremely high energy density and can meet the growing energy needs of mankind. However, the nuclear fission process produces a large amount of radioactive isotope pollutants, such as the radioactive nuclide technetium-99 ( 99 Tc), mainly TcO4 - TcO4 - It has high solubility, high environmental mobility and difficult complexation. It is difficult to immobilize in the process of radioactive waste treatment and easily migrates and diffuses in groundwater, causing groundwater pollution. There is an urgent need to remove TcO4 from contaminated water. - Considering general laboratory disposal 99 TcO4 - Radiation risk, ReO4 with similar properties - Commonly used as 99 TcO4 - Research on non-radioactive alternatives to

[0003] Cationic polymer networks (CPNs) are a new type of positively charged unit material, which is widely used as a ReO4 - A series of imidazolium-based CPNs have been developed for the removal of perrhenate ions. However, studies have shown that the cationic imidazolium units are easily destroyed by OH-, and nuclear waste is typically highly alkaline, making them unsuitable for practical applications. Summary of the Invention

[0004] In response to the above problems, the present invention aims to provide a three-dimensional cationic polymer, a preparation method, and an application thereof. The three-dimensional cationic polymer provided by the present invention has a high density of pyridinium salt units and a large number of hydrophobic alkyl groups on its interpenetrating skeleton, which can ensure that perrhenate ions in the solution can still be efficiently removed under strong alkaline conditions.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a three-dimensional cationic polymer, which is prepared by polymerizing tetrakis(4-(bromomethyl)phenyl)methane and 2,2',6,6'-tetramethyl-4,4'-bipyridine. The chemical structure of the three-dimensional cationic polymer is shown in Formula I.

[0007] The present invention also provides a method for preparing the three-dimensional cationic polymer described in the above technical solution, comprising the following steps:

[0008] (1) mixing tetra(4-(bromomethyl)phenyl)methane, 2,2',6,6'-tetramethyl-4,4'-bipyridine and 1-methyl-2-pyrrolidinone, and then performing a degassing treatment to obtain a reaction solution;

[0009] (2) performing a Menschutkin reaction on the reaction solution to obtain a three-dimensional cationic polymer.

[0010] Preferably, the molar ratio of tetra(4-(bromomethyl)phenyl)methane to 2,2',6,6'-tetramethyl-4,4'-bipyridine is 1:(1.8-2.2).

[0011] Preferably, the degassing treatment is a freeze-vacuum-thaw cycle degassing treatment; the freezing is liquid nitrogen freezing; and the freeze-vacuum-thaw cycle degassing treatment is performed for 3-5 cycles.

[0012] Preferably, the degassing treatment is performed under flame sealing conditions.

[0013] Preferably, the temperature of the Menschutkin reaction is 100-150°C, and the reaction time is 5-10 days.

[0014] The application further provides a use of the three-dimensional cationic polymer as an adsorbent.

[0015] The application further provides a method for removing perrhenate ions, comprising the following steps:

[0016] The three-dimensional cationic polymer is added to a solution containing perrhenate ions for adsorption.

[0017] Preferably, the initial pH value of the solution containing perrhenate ions is 2-12; the concentration of perrhenate ions in the solution containing perrhenate ions is 1-1000 mg / L; and the mass of the three-dimensional cationic polymer to the volume of the solution containing perrhenate ions is 0.1-1.0 g / L.

[0018] The application provides a kind of three-dimensional cationic polymer, the three-dimensional cationic polymer is polymerized by tetra (4- (bromomethyl) phenyl) methane and 2,2', 6,6'-tetramethyl-4,4'-bipyridine, and the chemical structural formula of the three-dimensional cationic polymer is specifically shown in formula I.The Menschutkin reaction is prepared by using tetra (4- (bromomethyl) phenyl) methane (TBPM) and 2,2', 6,6'-tetramethyl-4,4'-bipyridine (TMP) as reaction monomer, and the three-dimensional cationic polymer (TMP-TBPM) is prepared.The three-dimensional cationic polymer provided by the application has high density pyridinium salt units and a large number of hydrophobic alkyl groups on the interpenetrating skeleton, which improves the adsorption dynamics and adsorption selectivity of the material to perrhenate ions, thereby realizing high selectivity and ultrafast removal of perrhenate ions in water, and ensuring that TMP-TBPM can still realize fast and high-selectivity removal of perrhenate ions through ion exchange mechanism under strong acid or strong base conditions.

[0019] The application also provides a preparation method of the three-dimensional cationic polymer, which is simple in process and friendly to environment. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a synthesis route diagram of the three-dimensional cationic polymer TMP-TBPM.

[0021] Figure 2 It is the FT-IR spectrum of TMP, TBPM and TMP-TBPM prepared in Example 1.

[0022] Figure 3 It is the FT-IR spectrum of TMP-TBPM prepared in Example 1 before and after different irradiation and acid and alkali soaking treatment.

[0023] Figure 4 It is the nitrogen adsorption-desorption isotherm of TMP-TBPM prepared in Example 1.

[0024] Figure 5 It is the adsorption thermodynamic curve of TMP-TBPM to ReO4 - in Application Example 1.

[0025] Figure 6 It is the adsorption kinetics curve of TMP-TBPM to ReO4 - in Application Example 1. DETAILED DESCRIPTION

[0026] The application provides a kind of three-dimensional cationic polymer, the three-dimensional cationic polymer is polymerized by tetra (4- (bromomethyl) phenyl) methane and 2,2', 6,6'-tetramethyl-4,4'-bipyridine, and the chemical structural formula of the three-dimensional cationic polymer is shown in formula I.

[0027]

[0028] The application further provides a preparation method of the three-dimensional cationic polymer.

[0029] (1) mixing tetra(4-(bromomethyl)phenyl)methane, 2,2',6,6'-tetramethyl-4,4'-bipyridine and 1-methyl-2-pyrrolidone, and then performing degassing treatment to obtain a reaction solution;

[0030] (2) performing Menschutkin reaction on the reaction solution to obtain the three-dimensional cationic polymer.

[0031] In the application, the tetra(4-(bromomethyl)phenyl)methane and 2,2',6,6'-tetramethyl-4,4'-bipyridine have a molar ratio of preferably 1: (1.8-2.2) and more preferably 1:2; the 1-methyl-2-pyrrolidone is preferably anhydrous 1-methyl-2-pyrrolidone; the mixing is preferably ultrasonic mixing; the ultrasonic mixing time is preferably 10-30 min; the mixing container is preferably a quartz tube; the degassing treatment is preferably freeze-vacuum- thaw cycle degassing; the freezing is preferably liquid nitrogen freezing; the freeze-vacuum-thaw cycle degassing is preferably 3-5 cycles; and the degassing treatment is preferably performed under flame sealing conditions.

[0032] After obtaining the reaction solution, the application performs Menschutkin reaction on the reaction solution to obtain the three-dimensional cationic polymer. Before the reaction, the application also preferably performs ultrasonic treatment on the reaction solution; the ultrasonic treatment time is preferably 10 min; the Menschutkin reaction temperature is preferably 100-150°C and more preferably 120°C; the time is preferably 5-10 days and more preferably 7 days; the Menschutkin reaction is preferably performed in an oven; and the reaction formula of the Menschutkin reaction is as shown in Figure 1

[0033] After the Menschutkin reaction is completed, the application also preferably performs centrifugal separation on the obtained reaction solution, collects the solid product, and then sequentially performs washing and vacuum drying on the solid product; the washing is preferably sequentially washing the solid product with dichloromethane and water; the vacuum drying temperature is preferably 90-100°C, and the time is preferably 12-24 h.

[0034] ​The application further provides application of the three-dimensional cationic polymer prepared by the preparation method to an adsorbent.

[0035] The application further provides a method for removing perrhenate ions, comprising the following steps:

[0036] The three-dimensional cationic polymer prepared by the method is added to a solution containing perrhenate ions for adsorption.

[0037] In the application, the concentration of perrhenate ions in the solution containing perrhenate ions is preferably 1-1000 mg / L, more preferably 50-450 mg / L, and further preferably 50 mg / L; the mass of the three-dimensional cationic polymer to the volume of the solution containing perrhenate ions is 0.1-1.0 g / L, more preferably 0.5 g / L; the initial pH value of the solution containing perrhenate ions is preferably 2-12, more preferably 7; when the initial pH value of the solution containing perrhenate ions is not within the above range, the pH value of the solution containing perrhenate ions is preferably adjusted to 2-12 before adsorption; when the initial pH value of the mixed solution is 2-12, the pH value adjusting step can be omitted; the reagent for adjusting the pH value is preferably nitric acid and sodium hydroxide solution; the adsorption is preferably carried out under stirring; the stirring speed is preferably 120 rpm; and the adsorption time is preferably 12-24 h.

[0038] In order to further illustrate the application, the three-dimensional cationic polymer, the preparation method and the application thereof provided by the application are described in detail below with reference to examples, but they should not be understood as limiting the protection scope of the application.

[0039] Example 1

[0040] 0.5 mmol of tetra(4-(bromomethyl)phenyl)methane (TBPM), 1.0 mmol of 2,2',6,6'-tetramethyl-4,4'-bipyridine (TMP) and 9.0 mL of anhydrous 1-methyl-2-pyrrolidone were added into a 25 mL quartz tube for ultrasonic treatment for 10 min to obtain a mixed solution; the quartz tube containing the mixed solution was quickly frozen in a liquid nitrogen bath, degassed through three cycles of freezing-vacuumizing-thawing and flame-sealed, and the degassed mixed solution was ultrasonically treated for 10 min to obtain a reaction solution; the quartz tube containing the reaction solution was placed in a 120℃ oven, and left for 7 days; the reaction was completed, the reaction solution was naturally cooled to room temperature, centrifuged, and the solid product was collected, washed with dichloromethane and water, and then vacuum-dried at 90℃ for 12 hours to obtain the three-dimensional cationic polymer TMP-TBPM.

[0041] Application Example 1

[0042] 5 mg of the TMP-TBPM prepared in Example 1 was added to 10 mL of a solution containing different concentrations of perrhenate ions, the pH value of the solution was adjusted to 7.0 with nitric acid and sodium hydroxide solution, adsorption was carried out under the condition of stirring at 120 rpm for 12 h, and a suspension was obtained. The obtained suspension was filtered through a 0.22 μm microporous filter membrane, the filtrate was collected, and the concentration of the remaining ReO4 - was measured by inductively coupled plasma mass spectrometry. It was calculated that the adsorption capacity of TMP-TBPM for ReO4 - was 918.7 mg / g.

[0043] The adsorption capacity calculation formula is as follows: q e = (C0– C e ) / m × V, V is the volume of the mixed solution, unit: L; m is the amount of use of the three-dimensional cationic polymer, unit: g; C0is the initial concentration of ReO4 - , unit: mg / L; C e is the equilibrium concentration of ReO4 - , unit: mg / L.

[0044] Application Example 2

[0045] ReO4 - was adsorbed by the method of Application Example 1, and other conditions were the same as those of Application Example 1, except that the pH value of the solution in Application Example 1 was changed from 7.0 to 2.0, and the concentration of perrhenate ions in the solution containing perrhenate ions was 50 mg / L.

[0046] The adsorption capacity of TMP-TBPM for ReO4 - was 95.67 mg / g.

[0047] Application Example 3

[0048] ReO4 - was adsorbed by the method of Application Example 1, and other conditions were the same as those of Application Example 1, except that the pH value of the solution in Application Example 1 was changed from 7.0 to 3.0, and the concentration of perrhenate ions in the solution containing perrhenate ions was 50 mg / L.

[0049] The adsorption capacity of TMP-TBPM for ReO4 - was 99.56 mg / g.

[0050] Application Example 4

[0051] ReO4 -Adsorption was carried out according to the method of Application Example 1, except that the pH value of the solution in Application Example 1 was changed from 7.0 to 4.0, and the concentration of perrhenate ions in the solution containing perrhenate ions was 50 mg / L.

[0052] The adsorption capacity of TMP-TBPM for ReO4 - was 99.72 mg / g.

[0053] Application Example 5

[0054] Adsorption of ReO4 - was carried out according to the method of Application Example 1, except that the pH value of the solution in Application Example 1 was changed from 7.0 to 5.0, and the concentration of perrhenate ions in the solution containing perrhenate ions was 50 mg / L.

[0055] The adsorption capacity of TMP-TBPM for ReO4 - was 99.78 mg / g.

[0056] Application Example 6

[0057] Adsorption of ReO4 - was carried out according to the method of Application Example 1, except that the pH value of the solution in Application Example 1 was changed from 7.0 to 6.0, and the concentration of perrhenate ions in the solution containing perrhenate ions was 50 mg / L.

[0058] The adsorption capacity of TMP-TBPM for ReO4 - was 99.87 mg / g.

[0059] Application Example 7

[0060] Adsorption of ReO4 - was carried out according to the method of Application Example 1, except that the pH value of the solution in Application Example 1 was changed from 7.0 to 8.0, and the concentration of perrhenate ions in the solution containing perrhenate ions was 50 mg / L.

[0061] The adsorption capacity of TMP-TBPM for ReO4 - was 99.84 mg / g.

[0062] Application Example 8

[0063] Adsorption of ReO4 - was carried out according to the method of Application Example 1, except that the pH value of the solution in Application Example 1 was changed from 7.0 to 9.0, and the concentration of perrhenate ions in the solution containing perrhenate ions was 50 mg / L.

[0064] TMP-TBPM has an adsorption capacity of 99.45 mg / g for ReO4 - .

[0065] Example 9

[0066] TMP-TBPM has an adsorption capacity of 99.45 mg / g for ReO4 - , and the other conditions are the same as in Example 1, except that the pH of the solution in Example 1 is changed from 7.0 to 10.0, and the concentration of perrhenate ions in the solution containing perrhenate ions is 50 mg / L.

[0067] TMP-TBPM has an adsorption capacity of 99.45 mg / g for ReO4 - .

[0068] Example 10

[0069] TMP-TBPM has an adsorption capacity of 99.45 mg / g for ReO4 - , and the other conditions are the same as in Example 1, except that the pH of the solution in Example 1 is changed from 7.0 to 11.0, and the concentration of perrhenate ions in the solution containing perrhenate ions is 50 mg / L.

[0070] TMP-TBPM has an adsorption capacity of 99.45 mg / g for ReO4 - .

[0071] Example 11

[0072] TMP-TBPM has an adsorption capacity of 99.45 mg / g for ReO4 - , and the other conditions are the same as in Example 1, except that the pH of the solution in Example 1 is changed from 7.0 to 12.0, and the concentration of perrhenate ions in the solution containing perrhenate ions is 50 mg / L.

[0073] TMP-TBPM has an adsorption capacity of 99.45 mg / g for ReO4 - .

[0074] Comparative Example 1

[0075] TMP-TBPM has an adsorption capacity of 99.45 mg / g for ReO4 - , and the other conditions are the same as in Example 1, except that the TMP-TBPM prepared in Example 1 is changed to TEPM-EP-Br, which is from 3D lonic Olefin-Linked Conjugated Microporous Polymers for Selective Detection and Removal of TcO4 - / ReO4 -from Wastewater, Jia-Xin Qi, Analytical Chemistry, May 2, 2022.

[0076] TEPM-EP-Br adsorption capacity of ReO4 - is 345.68mg / g.

[0077] Comparative Example 2

[0078] ReO4 - was adsorbed by referring to the method of Application Example 1, and other conditions were the same as those of Application Example 1, except that TMP-TBPM prepared in Application Example 1 was replaced by Tp-BDOH-AB, which was from Lonic liquid modified covalent organic frameworks for efficient detection and adsorption of ReO4 - / TcO4 - , Shun-Mo Yi, Received 3 February 2022.

[0079] Tp-BDOH-AB adsorption capacity of ReO4 - is 439mg / g.

[0080] Comparative Example 3

[0081] ReO4 - was adsorbed by referring to the method of Application Example 1, and other conditions were the same as those of Application Example 1, except that TMP-TBPM prepared in Application Example 1 was replaced by ImPOP-1, which was from Evaluation of an lmidazolium-Based Porous Organic Polymer as Radioactive Waste Scavenger, Zhi-Wei Liu, Environmental Science and Technology, Technol, 2020.

[0082] ImPOP-1 adsorption capacity of ReO4 - is 610mg / g.

[0083] Performance test of three-dimensional cationic polymer

[0084] The three-dimensional cationic polymer TMP-TBPM obtained in Example 1 was characterized by infrared spectroscopy, Figure 2The Fourier transform infrared spectrum (FT-IR) of TMP, TBPM and TMP-TBPM prepared in Example 1 is shown in Figure 1. Figure 2 It can be seen that the characteristic absorption band (about 612 cm -1 ) of C-Br bond in TBPM disappears, and the strong absorption band (about 1639 cm -1 ) of quaternary pyridine species in TMP-TBPM appears, which proves that TMP-TBPM is successfully synthesized.

[0085] Chemical stability test: The TMP-TBPM prepared in Example 1 is respectively irradiated by 600 kGy beta-rays, 200 kGy beta-rays, 600 kGy gamma-rays and 200 kGy gamma-rays for 3 days, and the infrared spectrum is used to characterize the TMP-TBPM before and after treatment; in addition, the TMP-TBPM prepared in Example 1 is respectively soaked in 6.0 mol / L NaOH and 6.0 mol / L HNO3 for 3 days, and the infrared spectrum is used to characterize the TMP-TBPM before and after treatment; Figure 3 The FT-IR spectra of TMP-TBPM prepared in Example 1 before and after different irradiation and acid-base soaking treatment are shown in Figure 2. Figure 3 It can be seen that the FT-IR spectra of the three-dimensional cationic polymer before and after treatment do not change significantly, so it can be known that the three-dimensional cationic polymer TMP-TBPM has good chemical stability.

[0086] Figure 4 The nitrogen adsorption-desorption isotherm of TMP-TBPM prepared in Example 1 is shown in Figure 3. Figure 4 It can be seen that the BET specific surface area of TMP-TBPM is 99.38 m 2 g -1 .

[0087] Figure 5 The adsorption thermodynamic curve of TMP-TBPM for ReO4 - in Application Example 1 is shown in Figure 4. Figure 5 It can be seen that the adsorption capacity of TMP-TBPM for ReO4 - increases with the increase of the concentration of ReO4 - until the adsorption equilibrium is reached, and the adsorption process conforms to the Langmuir model, which indicates that the adsorption of TMP-TBPM for ReO4 - is monolayer adsorption, and the maximum adsorption capacity of TMP-TBPM for ReO4 - is 918.7 mg / g, so the skeleton of the cationic organic polymer TMP-TBPM synthesized in the application contains a large number of positive charges, which can realize the efficient adsorption of ReO4 - .

[0088] Figure 6 The adsorption kinetics curve of TMP-TBPM to ReO4 - in application example 1 can be known from Figure 6 TMP-TBPM to ReO4 - adsorption reaches dynamic equilibrium within 1 min, because TMP-TBPM has high-density pyridinium salt units and a large number of hydrophobic alkyl groups on the three-dimensional interpenetrating skeleton, which can promote the rapid mass transfer of ReO4 - , thereby greatly improving the adsorption capacity of ReO4 - . The experimental results conform to the pseudo-second-order kinetics model, indicating that the adsorption of TMP-TBPM to ReO4 - is mainly chemical adsorption.

[0089] In summary, the three-dimensional cationic polymer TMP-TBPM provided by the application has excellent stability and extremely high perrhenate ion adsorption capacity, and can be used as an efficient adsorbent for perrhenate ions.

[0090] The above only describes the preferred embodiments of the application, and does not limit the application in any form. It should be noted that, for those skilled in the art, without departing from the principles of the application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered within the protection scope of the application.

Claims

1. A three-dimensional cationic polymer as an adsorbent for adsorbing perrhenate, characterized in that: The three-dimensional cationic polymer is polymerized from tetrakis(4-(bromomethyl)phenyl)methane and 2,2′,6,6′-tetramethyl-4,4′-bipyridine. The chemical structure of the three-dimensional cationic polymer is shown in Formula I:

2. The use according to claim 1, characterized in that The preparation method of the three-dimensional cationic polymer comprises the following steps: (1) Tetrakis(4-(bromomethyl)phenyl)methane, 2,2′,6,6′-tetramethyl-4,4′-bipyridine, and 1-methyl-2-pyrrolidone are mixed and degassed to obtain a solution to be reacted; (2) subjecting the solution to be reacted to a Menschutkin reaction to obtain a three-dimensional cationic polymer.

3. The use according to claim 2, characterized in that The molar ratio of tetrakis(4-(bromomethyl)phenyl)methane to 2,2',6,6'-tetramethyl-4,4'-bipyridine is 1:(1.8-2.2).

4. The use according to claim 2, characterized in that The degassing treatment is freeze-vacuum-thaw cycle degassing; the freezing is liquid nitrogen freezing; the number of cycles of the freeze-vacuum-thaw cycle degassing is 3 to 5 times.

5. The use according to claim 2 or 4, characterized in that The degassing treatment is carried out under flame sealing conditions.

6. The use according to claim 2, characterized in that The temperature of the Menschutkin reaction is 100-150° C., and the time is 5-10 days.

7. The use according to claim 1, characterized in that The following steps are involved: The three-dimensional cationic polymer is added into a solution containing perrhenate ions for adsorption.

8. The use according to claim 7, characterized in that The initial pH value of the solution containing perrhenate ions is 2-12; the concentration of perrhenate ions in the solution containing perrhenate ions is 1-1000 mg / L; and the volume ratio of the mass of the three-dimensional cationic polymer to the solution containing perrhenate ions is 0.1-1.0 g / L.

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