Preparation method and application of sulfonated aromatic uranium adsorption film

Abstract

This invention relates to the field of uranium adsorption materials, and particularly to a method for preparing and applying a sulfonated aromatic uranium adsorption membrane. A polymer is dissolved in an organic solvent to obtain a casting solution; the casting solution is then used to prepare a membrane, resulting in the sulfonated aromatic uranium adsorption membrane. The polymer's structural formula is shown in Formula I. This invention provides a novel sulfonated aromatic uranium adsorption membrane suitable for uranium extraction from seawater. This invention develops a uranium adsorption membrane containing sulfonic acid groups and amide groups. The sulfonic acid groups, which specifically recognize uranium, and the hydrophilic amide groups endow the membrane adsorption material with excellent uranium adsorption kinetics and adsorption efficiency. Experimental results show that the sulfonated aromatic uranium adsorption membrane prepared using the method of this invention has an equilibrium adsorption time of 120 min and a uranium enrichment efficiency of 95.8%.

Description

Technical Field

[0001] This invention relates to the field of uranium adsorption materials, and in particular to a method for preparing and applying a sulfonated aromatic uranium adsorption membrane. Background Technology

[0002] Uranium, as the "food" of the nuclear industry, holds significant strategic importance in the development of clean energy and national defense. Oceans are rich in uranium resources, with total reserves exceeding 4 billion tons, making them an ideal natural uranium depot. Adsorption methods, with their advantages of high separation efficiency, low environmental pollution, and high economic benefits, have become the most common and effective method for obtaining uranium resources. The key to adsorption methods lies in the adsorbent material; organic polymer membrane adsorbents with self-supporting structures are ideal uranium adsorbents. However, mainstream aminooxime-based uranium adsorbents suffer from poor hydrophilicity and limited adsorption sites, resulting in low adsorption efficiency. Therefore, improving the hydrophilicity of the membrane material while simultaneously endowing the molecular backbone with multiple adsorption sites is a crucial approach to enhancing uranium adsorption kinetics and achieving high adsorption efficiency. Summary of the Invention

[0003] Based on the above, this invention provides a method for preparing a sulfonated aromatic uranium adsorption membrane with a fast adsorption rate and high adsorption efficiency, as well as its application. The sulfonated aromatic uranium adsorption membrane prepared using this method exhibits rapid uranium adsorption kinetics and high uranium adsorption efficiency when applied to uranium extraction from seawater.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] One of the technical solutions of this invention is a polymer with the structural formula shown in Formula I:

[0006]

[0007] In Equation I, n is any integer from 264 to 380.

[0008] The second technical solution of the present invention is a method for preparing the above-mentioned polymer, comprising the following steps:

[0009] Step 1: Potassium 2,5-dihydroxybenzenesulfonate, dichlorobenzonitrile, solvent and catalyst are mixed and reacted to obtain a sulfonated aromatic intermediate;

[0010] Step 2: Place the sulfonated aromatic intermediate in water, add an alkaline solution to react, and obtain the polymer.

[0011] The third technical solution of this invention is a method for preparing a sulfonated aromatic uranium adsorption membrane, comprising the following steps:

[0012] The polymer of claim 1 is dissolved in an organic solvent to obtain a casting solution;

[0013] The casting solution is used to prepare a membrane to obtain the sulfonated aromatic uranium adsorption membrane.

[0014] The fourth technical solution of the present invention is a sulfonated aromatic uranium adsorption membrane prepared according to the above preparation method.

[0015] The fifth technical solution of the present invention is the application of the above-mentioned polymer or the above-mentioned sulfonated aromatic uranium adsorption membrane in the adsorption of uranium elements in water.

[0016] The present invention discloses the following technical effects:

[0017] This invention provides a novel sulfonated aromatic uranium adsorption membrane suitable for uranium extraction from seawater. The invention develops a uranium adsorption membrane containing sulfonic acid and amide groups. The sulfonic acid groups specifically recognize uranium, and the hydrophilic amide groups endow the membrane adsorption material with excellent uranium adsorption kinetics and adsorption efficiency. Experimental results show that the sulfonated aromatic uranium adsorption membrane prepared using the method of this invention has an equilibrium adsorption time of 120 min and a uranium enrichment efficiency of 95.8%. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The sulfonated aromatic intermediate in Example 1 1 H NMR spectrum.

[0020] Figure 2 The images show the FTIR spectra of the sulfonated aromatic intermediate and the sulfonated aromatic membrane material in Example 1.

[0021] Figure 3 This is a bar chart comparing the adsorption capacity and adsorption efficiency of the sulfonated aromatic uranium adsorption membrane in Example 1 with the reported CAP-type uranium adsorption material.

[0022] Figure 4 The infrared spectra of the sulfonated aromatic membrane materials prepared in Examples 2-3 are shown.

[0023] Figure 5 The uranium adsorption efficiency of the sulfonated aromatic uranium adsorption membrane in Example 2 is shown under different sodium chloride concentrations.

[0024] Figure 6 The figure shows the uranium adsorption efficiency of the sulfonated aromatic uranium adsorption membrane in Example 3 under different ion concentrations.

[0025] Figure 7This is a cross-sectional morphology diagram of the sulfonated aromatic uranium adsorption membrane in Example 4 before its use.

[0026] Figure 8 This is a cross-sectional morphology of the sulfonated aromatic uranium adsorption membrane after it has been recycled 5 times in Example 4. Detailed Implementation

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included within the scope of this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0030] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0031] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0032] The first aspect of this invention provides a polymer with the structural formula shown in Formula I:

[0033]

[0034] In Equation I, n is any integer from 264 to 380.

[0035] A second aspect of the present invention provides a method for preparing the above-mentioned polymer, comprising the following steps:

[0036] Step 1: Potassium 2,5-dihydroxybenzenesulfonate, dichlorobenzonitrile, solvent and catalyst are mixed and reacted to obtain a sulfonated aromatic intermediate;

[0037] Step 2: Place the sulfonated aromatic intermediate in water, add an alkaline solution to react, and obtain the polymer.

[0038] In a preferred embodiment of the present invention, in step 1, the molar ratio of potassium 2,5-dihydroxybenzenesulfonate to dichlorobenzonitrile is 1.0 to 1.1:1; the dichlorobenzonitrile is 2,6-dichlorobenzonitrile and / or 3,5-dichlorobenzonitrile; and the solvent is an aprotic organic solvent.

[0039] In some embodiments of the present invention, the aprotic organic solvent is one or more of dimethyl sulfoxide, sulfolane, and diphenyl sulfone.

[0040] In a preferred embodiment of the present invention, in step 1, the catalyst is a mixture of an alkali metal carbonate and a crown ether compound in a molar ratio of 1:2; the alkali metal carbonate is potassium carbonate or sodium carbonate; the crown ether compound is 18-crown ether-6 or 15-crown ether-5; the concentration of the catalyst in the reaction system is 5 wt% to 15 wt%; the reaction is carried out under an inert atmosphere, at a temperature of 160 to 175°C, at a pressure of 1.5 to 2.2 MPa, and for a time of 8 to 12 h.

[0041] In some embodiments of the present invention, the inert atmosphere is an argon atmosphere.

[0042] In a preferred embodiment of the present invention, the ratio of potassium 2,5-dihydroxybenzenesulfonate to water and alkaline solution is 10-11 mmol: 36 mL: 54 mL; the alkaline solution is a sodium hydroxide solution or potassium hydroxide solution with a concentration of 2 wt% to 7 wt%.

[0043] In a preferred embodiment of the present invention, step 2 further includes adding acid to the reaction system to adjust the pH of the reaction system to neutral so that the polymer precipitates, and then filtering, washing and drying in sequence.

[0044] A third aspect of this invention provides a method for preparing a sulfonated aromatic uranium adsorption membrane, comprising the following steps:

[0045] The polymer of claim 1 is dissolved in an organic solvent to obtain a casting solution;

[0046] The casting solution is used to prepare a membrane to obtain the sulfonated aromatic uranium adsorption membrane.

[0047] In preparing the casting solution, the present invention does not impose any particular limitation on the amount of organic solvent used; the amount of organic solvent used is sufficient to ensure the complete dissolution of the polymer.

[0048] In a preferred embodiment of the present invention, the organic solvent is one or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; the sulfonated aromatic uranium adsorption membrane is obtained by coating the casting solution onto the substrate and then placing it in water for phase inversion for 8 to 12 hours.

[0049] A fourth aspect of the present invention provides a sulfonated aromatic uranium adsorption membrane prepared according to the above-described preparation method.

[0050] The fifth aspect of the present invention provides the application of the above-described polymer or the above-described sulfonated aromatic uranium adsorption membrane in the adsorption of uranium in water.

[0051] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0052] The testing methods involved in this invention are as follows:

[0053] Uranium adsorption test method: 10 mg of sulfonated aromatic uranium adsorption membrane was placed in a 250 mL spiked uranium solution with an initial uranium concentration of 20 ppm. Uranium adsorption test was carried out under magnetic stirring. Azoarsine trioxide was used as the colorimetric reagent. The change in uranium concentration in the solution was monitored by UV-Vis. When the uranium concentration in the solution became constant, it was considered that adsorption equilibrium was reached. The time taken was regarded as the equilibrium time. The difference between the initial uranium concentration and the equilibrium concentration and the ratio of the difference to the initial concentration was regarded as the uranium adsorption efficiency.

[0054] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0055] Example 1

[0056] (1) Under an inert atmosphere, potassium 2,5-dihydroxybenzenesulfonate (10.1 mmol), 3,5-dichlorobenzonitrile (10 mmol), 36 mL of dimethyl sulfoxide, potassium carbonate and 18-crown ether-6 complex (the molar ratio of potassium carbonate to 18-crown ether-6 is 1:2; the concentration of the complex in the reaction system is 5 wt%) were transferred to a high-pressure reactor, heated to 160 °C, controlled the reactor pressure at 1.5 MPa, and stirred continuously for 8 h to obtain a sulfonated aromatic intermediate;

[0057] (2) The above sulfonated aromatic intermediate was dispersed in 36 mL of ultrapure water, and 54 mL of 2 wt% sodium hydroxide solution was added. The changes of relevant functional groups were monitored by Fourier transform infrared spectroscopy. After the cyano group was completely disappeared and the amide bond was completely generated, hydrochloric acid was added to the reaction system to adjust the pH of the reaction system to neutral. The precipitated substances were filtered, washed and dried in sequence to obtain the target adsorbent molecule (sulfonated aromatic membrane material).

[0058] (3) Dissolve the sulfonated aromatic membrane material in dimethyl sulfoxide (the amount of organic solvent should be sufficient to fully dissolve the sulfonated aromatic membrane material) to obtain a casting solution; coat the casting solution onto a glass substrate and place it in water for phase inversion for 10 hours (8-12 hours is acceptable) to obtain a sulfonated aromatic uranium adsorption membrane.

[0059] The structural formula of the sulfonated aromatic membrane material prepared in this embodiment is:

[0060]

[0061] Figure 1 The sulfonated aromatic intermediate in Example 1 1 HNMR spectrum, by Figure 1 It can be seen that the hydrogen atoms in each environment are well assigned. Figure 2 The images show the FTIR spectra of the sulfonated aromatic intermediate and the sulfonated aromatic membrane material in Example 1. Figure 2 It can be seen that both contain methyl groups (2963cm). -1 Hydrogen bonding association of hydroxyl groups in sulfonic acid groups (3700-2800 cm⁻¹) -1 ), sulfone group in sulfonic acid group (1023cm) -1 The stretching vibration characteristic peaks of the three are as follows: Compared to sulfonated aromatic intermediates, the peaks are at 2234 cm⁻¹. -1 The characteristic vibrational peak (CN) was significantly weakened at 1673 cm⁻¹ in the FTIR spectrum of sulfonated aromatic membrane materials. -1 The carbonyl stretching vibration observed in (CONH2) indicates that the cyano group has transformed into an amide bond. 1 The HNMR and FTIR spectra show that the sulfonated aromatic membrane material has been successfully synthesized.

[0062] Figure 3A bar chart comparing the adsorption capacity and adsorption efficiency of the sulfonated aromatic uranium adsorption membrane in Example 1 with that of the reported CAP-type uranium adsorbent (New J. Chem., 2023, 47, 14364) is shown. It can be seen that the sulfonated aromatic uranium adsorption membrane of the present invention has an equilibrium time of 120 min and an adsorption efficiency of 95.8%. Compared with the reported CAP equilibrium time (900 min) and adsorption efficiency (74.6%), the sulfonated aromatic uranium adsorption membrane of the present invention exhibits faster adsorption kinetics and higher uranium adsorption efficiency. The equilibrium adsorption capacity of the sulfonated aromatic uranium adsorption membrane prepared in Example 1 is 479 mg / g.

[0063] Example 2

[0064] (1) Under an inert atmosphere, potassium 2,5-dihydroxybenzenesulfonate (11.0 mmol), 3,5-dichlorobenzonitrile (10 mmol), 40 mL of diphenyl sulfone, sodium carbonate and 18-crown ether-6 complex (the molar ratio of sodium carbonate to 18-crown ether-6 is 1:2; the concentration of the complex in the reaction system is 15 wt%) were transferred to a high-pressure reactor, heated to 175 °C, controlled the reactor pressure at 2.2 MPa, and stirred continuously for 12 h to obtain a sulfonated aromatic intermediate;

[0065] (2) The above sulfonated aromatic intermediate was dispersed in 36 mL of ultrapure water, and 54 mL of 7 wt% potassium hydroxide solution was added. The changes of relevant functional groups were monitored by Fourier transform infrared spectroscopy. After the cyano group was completely disappeared and the amide bond was completely generated, hydrochloric acid was added to the reaction system to adjust the pH of the reaction system to neutral. The precipitated substances were filtered, washed and dried in sequence to obtain the target adsorbent molecule (sulfonated aromatic membrane material).

[0066] (3) Same as step (3) in Example 1.

[0067] The structural formula of the sulfonated aromatic membrane material prepared in this embodiment is:

[0068]

[0069] Figure 4 In Figure a, the infrared spectrum of the sulfonated aromatic membrane material in Example 2 shows that amide bonds and sulfonic acid groups appeared in the target adsorption membrane material, indicating the successful synthesis of the target molecule. Figure 5The uranium adsorption efficiency of the sulfonated aromatic uranium adsorption membrane in Example 2 was measured under different sodium chloride concentrations (i.e., based on the above uranium adsorption test method, 200 ppm, 400 ppm, 600 ppm, 800 ppm, 1000 ppm, and 2000 ppm of sodium chloride were added to a 250 mL spiked uranium solution with an initial uranium concentration of 20 ppm, respectively). It can be seen that the adsorption efficiency of the sulfonated aromatic uranium adsorption membrane in salt solutions of 100–1000 ppm remains almost unchanged, still above 85%, which demonstrates the good salt resistance of the sulfonated aromatic uranium adsorption membrane.

[0070] Example 3

[0071] (1) Under an inert atmosphere, potassium 2,5-dihydroxybenzenesulfonate (10.2 mmol), 2,6-dichlorobenzonitrile (10 mmol), 38 mL of sulfolane, potassium carbonate and 15-crown ether-5 complex (the molar ratio of potassium carbonate to 15-crown ether-5 is 1:2; the concentration of the complex in the reaction system is 10 wt%) were transferred to a high-pressure reactor, heated to 170 °C, and the reactor pressure was controlled at 1.8 MPa. After stirring continuously for 9 h, a sulfonated aromatic intermediate was obtained.

[0072] (2) The above sulfonated aromatic intermediate was dispersed in 36 mL of ultrapure water, and 54 mL of 5 wt% potassium hydroxide solution was added. The changes of relevant functional groups were monitored by Fourier transform infrared spectroscopy. After the cyano group disappeared completely and the amide bond was completely generated, hydrochloric acid was added to the reaction system to adjust the pH of the reaction system to neutral. The precipitated substances were filtered, washed and dried in sequence to obtain the target adsorbent molecule (sulfonated aromatic membrane material).

[0073] (3) Same as step (3) in Example 1.

[0074] The structural formula of the sulfonated aromatic membrane material prepared in this embodiment is:

[0075]

[0076] Figure 4 In Figure b, the infrared spectrum of the sulfonated aromatic uranium adsorption membrane in Example 3 shows that amide bonds and sulfonic acid groups appeared in the target adsorption membrane material, indicating the successful synthesis of the target molecule. Figure 6 The uranium adsorption efficiency of the sulfonated aromatic uranium adsorption membrane in Example 3 under different ion concentrations (i.e., based on the above uranium adsorption test method, 1000 ppm of Na was added to a 250 mL spiked uranium solution with an initial uranium concentration of 20 ppm). + K + Cu 2+ Mg 2+ Ca 2+As can be seen, under different ion interference conditions, the sulfonated aromatic uranium adsorption membrane still has good uranium adsorption efficiency, indicating that the sulfonated aromatic uranium adsorption membrane has good selectivity.

[0077] Example 4

[0078] (1) Under an inert atmosphere, potassium 2,5-dihydroxybenzenesulfonate (10.8 mmol), 2,6-dichlorobenzonitrile (10 mmol), 39 mL of dimethyl sulfoxide, sodium carbonate and 15-crown ether-5 complex (the molar ratio of sodium carbonate to 15-crown ether-5 is 1:2; the concentration of the complex in the reaction system is 7 wt%) were transferred to a high-pressure reactor, heated to 165 °C, controlled the reactor pressure at 1.6 MPa, and stirred continuously for 12 h to obtain a sulfonated aromatic intermediate;

[0079] (2) Disperse the above sulfonated aromatic intermediate in 36 mL of ultrapure water, add 54 mL of 4 wt% sodium hydroxide solution, monitor the changes of relevant functional groups using Fourier transform infrared spectroscopy, and after the cyano group completely disappears and the amide bond is completely generated, add hydrochloric acid to the reaction system to adjust the pH of the reaction system to neutral, filter, wash and dry the precipitated substances in sequence to obtain the target adsorbent molecule (sulfonated aromatic membrane material);

[0080] (3) Same as step (3) in Example 1.

[0081] The structural formula of the sulfonated aromatic membrane material prepared in this embodiment is:

[0082]

[0083] Figure 4 In Figure c, the infrared spectrum of the sulfonated aromatic uranium adsorption membrane in Example 4 shows that amide bonds and sulfonic acid groups appeared in the target adsorption membrane material, indicating the successful synthesis of the target molecule. Figure 7 This is a cross-sectional morphology image of the sulfonated aromatic uranium adsorption membrane in Example 4. Figure 8 The image shows the cross-sectional morphology of the sulfonated aromatic uranium adsorption membrane after 5 cycles in Example 4; for comparison. Figure 7 and Figure 8 It can be seen that after repeated adsorption and desorption cycles, the sulfonated aromatic uranium adsorption membrane maintains a good surface morphology; the uranium adsorption efficiency changes from the initial 95.4% to 94.6%, a decrease of only 0.8%, indicating that the sulfonated aromatic uranium adsorption membrane has good recycling performance.

[0084] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A polymer, characterized in that, The structural formula is shown as Formula I: In Formula I, n is any integer from 264 to 380.

2. A process for the preparation of the polymer of claim 1, characterized in that, The method comprises the following steps: Step 1, potassium 2,5-dihydroxybenzenesulfonate, dichlorobenzonitrile, a solvent and a catalyst are mixed to react, so as to obtain a sulfonated aromatic intermediate; Step 2, the sulfonated aromatic intermediate is placed in water, and a base solution is added to react, so as to obtain the polymer.

3. The method of claim 2, wherein the polymer is prepared by a process comprising: In step 1, the molar ratio of potassium 2,5-dihydroxybenzenesulfonate to dichlorobenzonitrile is 1.0-1.1:1; the dichlorobenzonitrile is 2,6-dichlorobenzonitrile and / or 3,5-dichlorobenzonitrile; the solvent is an aprotic organic solvent; the dosage ratio of potassium 2,5-dihydroxybenzenesulfonate to the solvent is 1.0-1.1 mmol:36-40 mL.

4. The method of claim 2, wherein the polymer is prepared by a process comprising: In step 1, the catalyst is a complex of an alkali metal carbonate and a crown ether compound with a molar ratio of 1:2; the alkali metal carbonate is potassium carbonate or sodium carbonate; the crown ether compound is 18-crown-6 or 15-crown-5; the concentration of the catalyst in the reaction system is 5wt%-15wt%; the reaction is carried out in an inert atmosphere, the reaction temperature is 160-175℃, the reaction pressure is 1.5-2.2 MPa, and the reaction time is 8-12 h.

5. The method of claim 2, wherein the polymer is prepared by a process comprising: The dosage ratio of the potassium 2,5-dihydroxybenzenesulfonate to water and the base solution is 10-11 mmol:36 mL:54 mL; the base solution is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 2wt%-7wt%.

6. The method of claim 2, wherein the polymer is prepared by a process comprising: In step 2, after the reaction is completed, the method further comprises the steps of adding an acid to the reaction system to adjust the pH of the reaction system to neutral so that the polymer is precipitated, and then filtering, washing and drying in sequence.

7. A method for preparing a sulfonated aromatic uranium adsorption membrane, characterized by, The method comprises the following steps: The polymer of claim 1 is dissolved in an organic solvent to obtain a casting solution; The casting solution is prepared into a film to obtain the sulfonated aromatic uranium adsorption film.

8. The method for preparing the sulfonated aromatic uranium adsorption membrane according to claim 7, characterized in that, The organic solvent is one or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; the sulfonated aromatic uranium adsorption film is obtained by coating the casting solution on a substrate and then performing phase inversion in water for 8-12 hours.

9. A sulfonated aromatic uranium adsorption film prepared by the preparation method of claim 7 or 8.

10. Use of the polymer of claim 1 or the sulfonated aromatic uranium adsorption film of claim 9 in adsorbing uranium elements in water.

Images