A polyoxymethylene-formaldehyde membrane and its production and use

Abstract

This invention belongs to the field of polymer membrane material technology and discloses a method for extracting uranium (UO2) from seawater. 2+ This invention discloses a novel separation membrane material, specifically a amine-oxime-modified polycarbonate membrane, its preparation method, and its applications. The invention uses polycarbonate (PC) as a matrix. First, cyano-modified polycarbonate (PCAN) is prepared by grafting cyano groups. Then, PC and PCAN are blended, and a base membrane material is prepared using a phase inversion method. Finally, through in-situ amine-oxime modification, an amine-oxime-modified polycarbonate membrane (PCAO) is obtained, which possesses advantages such as high adsorption capacity, easy recovery, good stability, and excellent recyclability. Furthermore, the polycarbonate membrane modified with amine-oxime groups exhibits highly efficient selective adsorption capacity for uranium, enabling the effective development of uranium resources in seawater. This not only alleviates the domestic shortage of these key energy materials but also significantly improves economic benefits.

Description

Technical Field

[0001] This invention belongs to the technical field of water treatment materials and polymer membrane materials, and specifically discloses a metamine oxime-modified polycarbonate membrane, its preparation method and application. Background Technology

[0002] The rapid development of human society is inseparable from the efficient development and utilization of basic energy sources. Currently, we still rely primarily on fossil fuels such as oil and coal. These traditional energy sources are not only being heavily depleted, but their use also causes serious environmental pollution problems. Therefore, seeking an efficient, convenient, and clean energy source has become a common goal pursued globally. Uranium, as a key energy material, is crucial for building a greener and more efficient future society.

[0003] Uranium resources in terrestrial ores are relatively limited, while seawater contains extremely abundant uranium resources. If effectively developed and utilized, it could meet global uranium demand. However, the uranium content in seawater is extremely low, and the complex marine environment makes it highly susceptible to contamination of adsorbent materials. Therefore, inventing a separation material for the effective development of uranium reserves in seawater could not only alleviate domestic shortages of these critical energy materials but also significantly improve economic efficiency.

[0004] Amine oxime-based materials exhibit high adsorption and selectivity for extremely low concentrations of uranium ions in seawater. Adsorbents modified with amine oxime groups demonstrate highly efficient selective adsorption of uranium. However, the recovery of uranium extraction materials from seawater is also crucial. Most amine oxime-based adsorbents suffer from poor mechanical properties, low recovery rates, or high preparation costs and demanding synthesis conditions, limiting their application in seawater adsorption.

[0005] Meanwhile, porous membrane-based materials have gradually attracted attention in recent years, showing broad application prospects in marine resources and environmental fields (such as seawater desalination and oil-water separation). Compared to adsorbent materials such as particles and gels, membrane-based materials offer advantages such as morphological stability, high mechanical strength, good separation properties, and sustainable operation, making them one of the ideal materials for researching and developing the simultaneous adsorption of uranium from seawater. Polycarbonate is a chain-like polymer material and one of the five major general-purpose engineering plastics, widely used in various fields of production and daily life. Its production cost is low and it is readily available. The bisphenol structure and polycarbonate bonds in the polycarbonate chain provide it with many excellent properties, such as good thermal stability, high mechanical strength, and high cold resistance, making it a good candidate membrane material. However, it does not inherently possess uranium adsorption capacity, and polycarbonate has high hydrophobicity, which seriously affects the development and application of polycarbonate-based membranes.

[0006] Therefore, how to prepare polycarbonate-based separation membranes with excellent uranium adsorption performance, easy separation and recovery, and good recycling performance using polycarbonate as a matrix has become an urgent problem for researchers to solve. Summary of the Invention

[0007] In view of this, the purpose of this invention is to address the problems existing in the prior art by providing a amine-oxime polycarbonate membrane, its preparation method, and its application. By using polycarbonate (PC) as a matrix, a membrane material is first prepared by grafting cyano groups and using a phase inversion method. Then, through in-situ amine-oxime modification, a uranium adsorption material with high adsorption capacity, excellent recyclability, and low cost is prepared.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] The first objective of this invention is to provide a method for preparing a metamine oxime-modified polycarbonate membrane, the method specifically comprising the following steps: (1) A certain amount of polycarbonate was dissolved in N-methylpyrrolidone, and a small amount of azobisisobutyronitrile was added as an initiator. After the polycarbonate was completely dissolved, acrylonitrile in the same proportion as the polycarbonate was added and reacted for a certain period of time. Then, the polycarbonate was washed with ultrapure water, filtered, dried and stored for later use to obtain cyanopolycarbonate (PCAN). (2) Dissolve a certain proportion of PCAN and PC in NMP and stir until dissolved to obtain casting solution; then, let the casting solution stand at room temperature for degassing treatment; (3) Before film preparation, the casting solution is ultrasonically treated; during film preparation, an appropriate amount of casting solution is poured onto a dry and flat glass plate, and the liquid film is scraped out at a uniform speed with a scraper. Then, the glass plate with the liquid film is immersed in ultrapure water. After the liquid film solidifies and falls off the glass plate, the solidified new film is transferred to clean ultrapure water for later use. (4) Wipe the surface of the membrane prepared in step (3) with filter paper and immerse the membrane completely in a mixed solution of hydroxylamine hydrochloride and sodium hydroxide for a certain period of time to carry out the amylopyrification reaction. Then soak it in ultrapure water to obtain the amylopyrified polycarbonate membrane (PCAO).

[0010] Further, in step (1), 3-5g of polycarbonate and 0.05-0.2g of initiator azobisisobutyronitrile are completely dissolved in 15-20mL of N-methylpyrrolidone, and then acrylonitrile is added. The mass ratio of acrylonitrile to polycarbonate is 1:1-4, the reaction temperature is 60-100℃, and the reaction time is 8h-12h.

[0011] Further, in step (2), PCAN and PC are dissolved in NMP with a mass ratio of 1.5:1 to 3:1, at a concentration of 79% NMP, and the solution is heated at 300 to 600 r·min.-1 Stir at a certain rate until dissolved, and let the casting solution stand at room temperature for 12-16 hours for degassing treatment.

[0012] Furthermore, in step (3), before film formation, the casting solution is subjected to ultrasonic treatment for 15-45 minutes; during film formation, a thin liquid film with a thickness of 200 μm is scraped out at a uniform speed using a film scraper, and the liquid film is exposed to air for 10-15 seconds.

[0013] Further, in step (4), the prepared membrane is completely immersed in a mixed solution of hydroxylamine hydrochloride and sodium hydroxide at 60℃~100℃ for 3h~5h, and the molar ratio of hydroxylamine hydrochloride and sodium hydroxide in the mixed solution is 3~5:2~4.

[0014] A second objective of this invention is to provide a metamidooxime-modified polycarbonate membrane prepared by the method described above, wherein the polycarbonate membrane is incorporating metamidooxime groups with specific adsorption properties for uranium through a simple and cost-effective method.

[0015] A third objective of this invention is to provide an application of the amylopyridine polycarbonate membrane prepared by the method described above in the fields of energy and materials.

[0016] Furthermore, the metamine oxime-modified polycarbonate membrane exhibits high selectivity and efficient adsorption capacity for uranium.

[0017] Furthermore, the amylated polycarbonate membrane can effectively extract uranium resources from seawater.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention utilizes polycarbonate (PC) as the matrix material, first preparing a membrane material by grafting cyano groups and employing a phase inversion method. Then, through in-situ amine oxime modification, a novel amine oxime-based adsorption and separation membrane was successfully developed. This membrane features a simple preparation method, easy recovery, good stability, and excellent recyclability. Combining the advantages of both polycarbonate and amine oxime groups, it exhibits high selectivity and efficient adsorption capacity, enabling uranium extraction in extremely low concentration seawater environments. This has significant strategic importance and practical application value in addressing uranium resource shortages. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1The FTIR plots are of PC, PCAN, and PCAO in Comparative Example 1 and Example 1.

[0021] Figure 2 The water contact angles of the PCAO surface are shown in Comparative Example 1 and the examples at different ratios.

[0022] Figure 3 Comparative Example 1 and different proportions of PCAO against UO2 in the examples 2+ The adsorption performance of PCAO is shown in (a) and (b) is shown in the adsorption images of Comparative Example 1 and Example 1. 2+ Adsorption performance.

[0023] Figure 4 The graph shows the cyclic adsorption performance of Example 2. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] The term "embodiment" used herein, as an example, is not necessarily to be construed as superior to or better than other embodiments. Performance testing in the embodiments of this application, unless otherwise specified, employs conventional testing methods in the art. It should be understood that the terminology used in this application is merely for describing particular implementations and is not intended to limit the scope of this disclosure.

[0026] Unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; other experimental methods and technical means not specifically mentioned herein refer to experimental methods and technical means commonly used by one of ordinary skill in the art.

[0027] To better illustrate the content of this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented even without certain specific details. In the embodiments, some methods, means, instruments, and devices well-known to those skilled in the art are not described in detail in order to highlight the main points of this application.

[0028] Without conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solution belongs to the content disclosed in the embodiments of this application.

[0029] This invention discloses a metamine oxime-modified polycarbonate membrane with high adsorption capacity and high selectivity, and its preparation method.

[0030] To better understand the present invention, the following embodiments are provided for further detailed description of the present invention, but they should not be construed as limiting the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are also considered to fall within the protection scope of the present invention.

[0031] The following will provide further explanation with reference to specific embodiments and some raw material information.

[0032] Polycarbonate: provided by Hainan Huasheng New Material Technology Co., Ltd. Azobisisobutyronitrile: purchased from Shanghai Maclean Biochemical Technology Co., Ltd.; Acrylonitrile: Purchased from Aladdin Biochemical Technology Co., Ltd.; Hydroxylamine hydrochloride: purchased from Xilong Scientific Co., Ltd. Sodium hydroxide: purchased from Xilong Scientific Co., Ltd.

[0033] Example 1: A method for preparing a metallo-oxime-modified polycarbonate membrane material (1) Dissolve 3g of polycarbonate in 15mL of N-methylpyrrolidone, add 0.1g of azobisisobutyronitrile as an initiator, and after dissolution, add acrylonitrile with a mass ratio of 1:1 to polycarbonate. React at 65℃ for 8h, wash with ultrapure water, filter, and dry for later use. PCAN was prepared by this method. (2) Dissolve PCAN and PC in NMP at a mass ratio of 1.5:1 and heat at 600 r·min -1 Stir magnetically until dissolved; then, allow the casting solution to stand at room temperature for 16 hours to degas; before film formation, sonicate the casting solution for 45 minutes to completely eliminate any air bubbles; during film formation, pour an appropriate amount of casting solution onto a dry, flat glass plate, spreading it into a long strip, and then use a scraper to scrape out a thin film of 200 μm thickness at a uniform speed. Expose the film to air for 10-15 seconds, then immerse the glass plate with the film in pre-prepared ultrapure water and wait for the film to solidify and gradually detach from the glass plate; then transfer the solidified new film to clean ultrapure water for later use.

[0034] (3) Wipe the surface of the prepared membrane dry with filter paper, and then immerse it completely in a mixed solution of NH2OH·HCl and NaOH at 60℃ for 3 hours. The molar ratio of NH2OH·HCl to NaOH in the mixed solution is 4:3. After that, it is stored in ultrapure water, and the water is changed every 12 hours. PCAO1 was prepared by this method.

[0035] It should be noted that, Figure 1 PCAN and PCAO are FTIR spectra of the sample from Example 1. Figure 2 PCAO1 is the water contact angle diagram of the sample in Example 1. Figure 3 (a) is an image of PCAO1 adsorbed in Example 1, and (b) is an image of PCAO1 adsorbing UO2 in Example 1. 2+ Adsorption performance.

[0036] Furthermore, based on the parameter selection in step (3) of the above embodiment 1, the following experiment was conducted: Experimental Example 1: According to the preparation method of a amine oxime-modified polycarbonate membrane described in Example 1, the prepared membrane was dried with filter paper and then completely immersed in a mixed solution of NH2OH·HCl and NaOH in a molar ratio of 4:3 at 60°C for 3 hours. Afterwards, it was stored in ultrapure water, with the water changed every 12 hours. PCAO1-1 was prepared using this method.

[0037] Experimental Example 2: According to the preparation method of a amine oxime-modified polycarbonate membrane described in Example 1, the prepared membrane was dried with filter paper and then completely immersed in a mixed solution of NH2OH·HCl and NaOH in a molar ratio of 4:3 at 60°C for 4 hours. Afterwards, it was stored in ultrapure water, with the water changed every 12 hours. PCAO1-2 was prepared using this method.

[0038] Experimental Example 3: According to the preparation method of a amine oxime-modified polycarbonate membrane described in Example 1, the prepared membrane was dried with filter paper and then completely immersed in a mixed solution of NH2OH·HCl and NaOH in a molar ratio of 4:3 at 60°C for 5 hours. Afterwards, it was stored in ultrapure water, with the water changed every 12 hours. PCAO1-3 was prepared using this method.

[0039] Experiment Example 4: According to the preparation method of a amine oxime-modified polycarbonate membrane described in Example 1, the prepared membrane was dried with filter paper and then completely immersed in a mixed solution of NH2OH·HCl and NaOH in a molar ratio of 3:2 at 60°C for 3 hours. Afterwards, it was stored in ultrapure water, with the water changed every 12 hours. PCAO1-4 was prepared using this method.

[0040] Experimental Example 5: According to the preparation method of a amine oxime-modified polycarbonate membrane described in Example 1, the prepared membrane was dried with filter paper and then completely immersed in a mixed solution of NH2OH·HCl and NaOH in a molar ratio of 3.5:2.5 at 60°C for 3 hours. Afterwards, it was stored in ultrapure water, with the water changed every 12 hours. PCAO1-5 was prepared using this method.

[0041] Experimental Example 6: According to the preparation method of a amine oxime-modified polycarbonate membrane described in Example 1, the prepared membrane was dried with filter paper and then completely immersed in a mixed solution of NH2OH·HCl and NaOH at 60℃ with a molar ratio of 4.5:3.5 for 3 hours. Afterwards, it was stored in ultrapure water, with the water changed every 12 hours. PCAO1-6 was prepared using this method.

[0042] Experiment Example 7: According to the preparation method of a amine oxime-modified polycarbonate membrane described in Example 1, the prepared membrane was dried with filter paper and then completely immersed in a mixed solution of NH2OH·HCl and NaOH in a molar ratio of 5:4 at 60°C for 3 hours. Afterwards, it was stored in ultrapure water, with the water changed every 12 hours. PCAO1-7 was prepared using this method.

[0043] Example 2: A method for preparing a amine oxime-modified polycarbonate membrane material (1) Dissolve 3g of polycarbonate in 15mL of N-methylpyrrolidone, add 0.1g of azobisisobutyronitrile as an initiator, and after dissolution, add acrylonitrile with a mass ratio of 1:1 to polycarbonate. React at 65℃ for 8h, wash with ultrapure water, filter, and dry for later use. (2) Dissolve PCAN and PC in NMP with a mass ratio of 2:1 at 500 r·min -1 Stir magnetically until dissolved; then, allow the casting solution to stand at room temperature for 15 hours to degas; before film formation, sonicate the casting solution for 35 minutes to completely eliminate any air bubbles; during film formation, pour an appropriate amount of casting solution onto a dry, flat glass plate, spreading it into a long strip, and then use a scraper to scrape out a thin film of 200 μm thickness at a uniform speed. Expose the film to air for 10-15 seconds, then immerse the glass plate with the film in pre-prepared ultrapure water and wait for the film to solidify and gradually detach from the glass plate; then transfer the solidified new film to clean ultrapure water for later use.

[0044] (3) Wipe the surface of the prepared membrane dry with filter paper and immerse it completely in a mixed solution of NH2OH·HCl and NaOH at 60℃ for 3 hours. The molar ratio of NH2OH·HCl to NaOH in the mixed solution is 4:3. Then, preserve it in ultrapure water and change the water every 12 hours.

[0045] It should be noted that, Figure 2 PCAO2 is the water contact angle diagram of the sample in Example 2. Figure 3 (b) shows the effect of PCAO2 on UO2 in Example 2. 2+ Adsorption performance, Figure 4 This is the cyclic adsorption performance of Example 2.

[0046] Example 3: A method for preparing a amine oxime-modified polycarbonate membrane material (1) Dissolve 3g of polycarbonate in 15mL of N-methylpyrrolidone, add 0.1g of azobisisobutyronitrile as an initiator, and after dissolution, add acrylonitrile with a mass ratio of 1:1 to polycarbonate. React at 65℃ for 8h, wash with ultrapure water, filter, and dry for later use. (2) Dissolve PCAN and PC in NMP at a mass ratio of 2.5:1 at 400 r·min -1 Stir magnetically until dissolved; then, allow the casting solution to stand at room temperature for 14 hours to degas; before film formation, sonicate the casting solution for 25 minutes to completely eliminate any air bubbles; during film formation, pour an appropriate amount of casting solution onto a dry, flat glass plate, spreading it into a long strip, and then use a scraper to scrape out a thin film of 200 μm thickness at a uniform speed. Expose the film to air for 10-15 seconds, then immerse the glass plate with the film in pre-prepared ultrapure water and wait for the film to solidify and gradually detach from the glass plate; then transfer the solidified new film to clean ultrapure water for later use.

[0047] (3) Wipe the surface of the prepared membrane dry with filter paper and immerse it completely in a mixed solution of NH2OH·HCl and NaOH at 60℃ for 3 hours. The molar ratio of NH2OH·HCl and NaOH in the mixed solution is 4:3. Then, preserve it in ultrapure water and change the water every 12 hours.

[0048] It should be noted that, Figure 2 PCAO3 is the water contact angle diagram of the sample in Example 3. Figure 3 (b) shows the effect of PCAO3 on UO2 in Example 3. 2+ Adsorption performance.

[0049] Example 4: A method for preparing a amine oxime-modified polycarbonate membrane material (1) Dissolve 3g of polycarbonate in 15mL of N-methylpyrrolidone, add 0.1g of azobisisobutyronitrile as an initiator, and after dissolution, add acrylonitrile with a mass ratio of 1:1 to polycarbonate. React at 65℃ for 8h, wash with ultrapure water, filter, and dry for later use. (2) Dissolve PCAN and PC in NMP with a mass ratio of 3:1 at 400 r·min -1 Stir magnetically until dissolved; then, allow the casting solution to stand at room temperature for 13 hours to degas; before film formation, sonicate the casting solution for 20 minutes to completely eliminate any air bubbles; during film formation, pour an appropriate amount of casting solution onto a dry, flat glass plate, spreading it into a long strip, and then use a scraper to scrape out a thin film of 200 μm thickness at a uniform speed. Expose the film to air for 10-15 seconds, then immerse the glass plate with the film in pre-prepared ultrapure water and wait for the film to solidify and gradually detach from the glass plate; then transfer the solidified new film to clean ultrapure water for later use.

[0050] (3) Wipe the surface of the prepared membrane dry with filter paper and immerse it completely in a mixed solution of NH2OH·HCl and NaOH at 60℃ for 3 hours. The molar ratio of NH2OH·HCl to NaOH in the mixed solution is 4:3. Then, preserve it in ultrapure water and change the water every 12 hours.

[0051] It should be noted that, Figure 2 PCAO4 is the water contact angle diagram of the sample in Example 4. Figure 4 (b) shows the effect of PCAO4 on UO2 in Example 4. 2+ Adsorption performance.

[0052] Comparative Example 1: A method for preparing a polycarbonate film material (1) Dissolve 21% polycarbonate in 79% N-methylpyrrolidone at 600 r·min -1 Stir magnetically until dissolved; (2) The casting solution was allowed to stand at room temperature for 16 hours to remove bubbles. Before casting, the casting solution was subjected to ultrasonic treatment for 45 minutes to completely eliminate any bubbles that might exist in the casting solution. When casting, an appropriate amount of casting solution was poured onto a dry and flat glass plate. The casting solution should be spread into a long strip. Then, a thin liquid film with a thickness of 200 μm was scraped out at a uniform speed with a scraper. The liquid film was exposed to the air for 10-15 seconds. Then, the glass plate with the liquid film was immersed in the prepared ultrapure water and waited for the liquid film to solidify and gradually fall off the glass plate. Then, the solidified new film was transferred to clean ultrapure water for later use.

[0053] It should be noted that, Figure 1 PC in the middle is the FTIR spectrum of sample 1 in Comparative Example 1. Figure 2 The diagram in PC shows the water contact angle of sample 1 in Comparative Example 1. Figure 3 (a) is a photograph of PC adsorption in Comparative Example 1, and (b) is a photograph of PC adsorbing UO2 in Comparative Example 1. 2+ Adsorption performance.

[0054] The scope of this invention is not limited to the above embodiments; a combination of one or more embodiments can also achieve the purpose of this invention.

[0055] To further verify the superior effects of the present invention, the inventors also conducted the following experiments: Experiment 1: Demonstrating the successful preparation of a methylamine oxime carbonate membrane To ensure successful PCAO preparation, Fourier transform infrared spectroscopy (FIR) was used to analyze PC, PCAN, and PCAO in Example 1. The samples were tested after KBr pelleting at a resolution of 4 cm⁻¹. -1 32 scans, 400cm scan range -1 -4000cm -1 .

[0056] Depend on Figure 1 It can be seen that the carbonate bonds contained in the PC structure have a characteristic peak at 1770 cm⁻¹. -1 Location, 1504 cm -1 The peak at 2243 cm⁻¹ is the skeletal vibration peak of the benzene ring in PC, providing excellent thermal stability and processability. PCAN contains a cyano group (-C=N) in its structure, which is visible at 2243 cm⁻¹ in its infrared spectrum. -1 The presence of the -C≡N characteristic peak at 1647 cm⁻¹ confirms this, indicating successful grafting of cyano groups onto polycarbonate. The disappearance of the cyano characteristic peak and the appearance of -C=N at 1647 cm⁻¹ in the PCAO infrared spectrum further supports this, demonstrating the successful grafting of cyano groups onto polycarbonate. -1 ) and -N-OH (933 cm -1 The characteristic peaks of the cyano group indicate that the cyano group was successfully cytosimified and the polycarbonate was successfully grafted with the cytosim group.

[0057] Experiment 2: Used to illustrate the hydrophilicity of amylopyridine carbonate membranes To further confirm the success of the membrane modification and evaluate the membrane's hydrophilic properties, the water contact angle of the membrane surface was studied and measured using a contact angle meter (SL200KB, Shanghai Solon Technology Information Co., Ltd.). Each membrane sample from the examples was tested three times at different locations.

[0058] Depend on Figure 2It is known that the amine oxime group helps to increase the hydrophilicity of the material.

[0059] Experiment 3: To illustrate the enhanced adsorption performance of amylopyridine carbonate membranes Prepare 50 μg·mL -1 UO2 2+ 200 mL of aqueous solution was used. PCAO samples from the example were cut to appropriate sizes and placed in the membrane chamber. Before starting the adsorption test, 1 mL of the solution was taken to measure the initial concentration, recorded as c0. The adsorption test was then started under the following conditions: pressure 0.3 MPa, circulating feed solution. After 3 hours of adsorption, 1 mL of the feed solution was taken and the UO2 concentration was measured. 2+ Concentration denoted as c t UO2 before and after adsorption was measured using a UV spectrophotometer. 2+ Concentration, tested at a wavelength of 652nm. First, prepare UO2. 2+ A standard curve for subsequent adsorption of UO2 2+ Concentration calculation. UO2 2+ The standard curve test is as follows: The concentration is prepared at 100 μg·mL. -1 UO2 2+ The solution was then pipetted into 15 mL centrifuge tubes at concentrations of 0 mL, 0.2 mL, 0.4 mL, 0.6 mL, 0.8 mL, and 1 mL, respectively. 0.5 mL of 0.1 mol·L⁻¹ solution was added to each centrifuge tube sequentially. -1 HCl, 1 mL 0.05 mol·L -1 Na2EDTA, 1 mL 0.5 mg / mL -1 The azoarsine III solution was prepared by pipetting 7.5 mL, 7.3 mL, 7.1 mL, 6.9 mL, 6.7 mL, and 6.5 mL of ultrapure water into the corresponding centrifuge tubes to prepare UO2. 2+ Concentrations of 0, 2, 4, 6, 8, and 10 μg·mL -1 UO2 2+ Standard solution.

[0060] Depend on Figure 3 It can be seen that the polycarbonate membrane modified by amylopyridine oxime reacts with UO2 after adsorption due to the interaction between the amylopyridine oxime groups and UO2. 2+ The membrane underwent a color change upon bonding, while the unmodified polycarbonate showed no significant change. This demonstrates that PCAO can significantly enhance the adsorption effect on uranium.

[0061] Experiment 4: To illustrate the reusability of the amylopyridine carbonate membrane. UO2 was adsorbed using a mixed solution of 200 mL of 0.1 mol / L H2O2 and 1 mol / L Na2CO3. 2+Desorption experiments were conducted on PCAO2, with a desorption time of 20 min. Subsequently, five adsorption-desorption cycles were performed on PCAO2.

[0062] Depend on Figure 4 It can be seen that as the number of cycles increases, PCAO2 affects UO2. 2+ The adsorption capacity will decrease slightly. The second adsorption capacity was 98.04% of the initial value. After five cycles, due to partial blockage of the membrane pores, this value dropped to 86.8%. It can be seen that although PCAO exhibits some performance degradation, it still demonstrates satisfactory recycling efficiency.

[0063] The above experiments demonstrate that the successful introduction of amine oxime groups into the polycarbonate matrix membrane significantly improves the hydrophilicity of the membrane material. The amine oxime groups can synergistically interact with uranium, thereby endowing polycarbonate with excellent uranium adsorption properties. Combining the advantages of polycarbonate and amine oxime groups, the material also exhibits good recyclability.

[0064] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a metamine oxime-modified polycarbonate membrane, characterized in that, Includes the following steps: (1) Polycarbonate was dissolved in N-methylpyrrolidone (NMP) and the initiator azobisisobutyronitrile (AIBN) was added. After the dissolution was complete, acrylonitrile was added to react. Then the mixture was washed with ultrapure water, filtered, dried and set aside to obtain cyano-modified polycarbonate (PCAN). (2) Dissolve PCAN and PC in NMP and stir until dissolved to obtain casting solution; then, let the casting solution stand at room temperature for degassing treatment; (3) Before film preparation, the casting solution is ultrasonically treated; during film preparation, an appropriate amount of casting solution is poured onto a dry and flat glass plate, and a thin liquid film is scraped out at a uniform speed with a scraper. Then, the glass plate with the liquid film is immersed in ultrapure water. After the liquid film solidifies and falls off the glass plate, the solidified new film is transferred to clean ultrapure water for later use. (4) The membrane prepared in step (3) is dried with filter paper and then completely immersed in a mixed solution of hydroxylamine hydrochloride and sodium hydroxide to carry out the amylopyrification reaction. After that, it is stored in ultrapure water to obtain the amylopyrified polycarbonate membrane (PCAO).

2. The method for preparing the amylopyridine-oxime polycarbonate membrane according to claim 1, characterized in that, In step (1), 3-5g of polycarbonate and 0.05-0.2g of initiator azobisisobutyronitrile are completely dissolved in 15-20mL of N-methylpyrrolidone, and then acrylonitrile is added. The mass ratio of acrylonitrile to polycarbonate is 1:1-4. The reaction temperature is 60-100℃ and the reaction time is 8-12h.

3. The method for preparing the amylopyridine-oxime polycarbonate membrane according to claim 1, characterized in that, In step (2), PCAN and PC are dissolved in NMP at a mass ratio of 1.5:1 to 3:1 and stirred until dissolved. The casting solution is then allowed to stand at room temperature for 12-16 hours for degassing treatment.

4. The method for preparing the amylopyridine-oxime polycarbonate membrane according to claim 1, characterized in that, In step (3), before film formation, the casting solution is subjected to ultrasonic treatment for 15-45 minutes; during film formation, a thin liquid film is scraped out at a uniform speed using a scraper, and the liquid film is exposed to air for 10-15 seconds.

5. The method for preparing the amylopyridine-oxime polycarbonate membrane according to claim 1, characterized in that, In step (4), the prepared membrane is completely immersed in a mixed solution of hydroxylamine hydrochloride and sodium hydroxide at 60℃~100℃ for 3h~5h. The molar ratio of hydroxylamine hydrochloride and sodium hydroxide in the mixed solution is 3~5:2~4.

6. A amine-oxime polycarbonate membrane prepared by the method of claim 1.

7. The application of a amine-oxime-modified polycarbonate membrane prepared by the method described in claim 1 in the fields of energy and materials.

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