Fluorenone polymer skin fiber membrane composite material, and preparation method and application thereof

Abstract

The application relates to the field of fiber membrane composite materials, and more particularly to a preparation method and application of a fluorenone polymer skin fiber membrane composite material. The fluorenone polymer skin fiber membrane composite material is prepared by using tris(4-aminophenyl)amine containing three amino coupling ends and 2,7-dibromofluorenone with bromo groups on both sides as reaction monomers and taking a skin fiber membrane as a base material. The material preparation method is simple, fast, green, efficient, mild and easy to recycle. The prepared fluorenone polymer skin fiber membrane composite adsorption material not only has rich N and O sites, but also has improved adsorption performance on uranium (U(Ⅵ)), cobalt (Co(Ⅱ)), strontium (Sr(Ⅱ)) and cesium (Cs(Ⅰ)) due to the introduced fluorenone groups. Meanwhile, the material has the characteristics of small diffusion resistance, fast mass transfer speed and radiation resistance stability, can solve the problems of difficult separation and difficult recovery of traditional powder materials, and has great social and economic benefits.

Description

Technical Field

[0001] This application relates to the field of fiber membrane composites, and more specifically to a fluorenone polymer skin fiber membrane composite material, its preparation method, and its application. Background Technology

[0002] In recent years, with the large-scale development and utilization of nuclear energy, nuclear safety has become a topic of widespread concern. The production of nuclear fuel and the operation of nuclear power plants generate large amounts of radioactive wastewater, which is discharged and exposed to natural ecological environments such as water and soil. The radioactive pollutants contained in this wastewater, such as common elements like uranium, cobalt, cesium, and strontium, not only exhibit the chemical toxicity of heavy metals but also pose potential risks and threats of radioactive radiation. Radioactive pollutants can have a significant impact on human health; exposure to radioactive substances can damage human tissues and organs, leading to various radiation-related diseases, including various types of cancer, dizziness, fatigue, hair loss, abnormal white blood cells, and thrombocytopenia. Therefore, how to effectively remove radionuclides from radioactive wastewater has become a widely studied topic among researchers.

[0003] Effective methods for treating radioactive wastewater mainly include chemical precipitation, filtration, ion exchange, evaporation, and membrane adsorption. Among these, membrane adsorption has attracted increasing attention for radionuclide removal due to its advantages such as simple operation, good economy, high efficiency, no secondary pollution, and continuous operation at room temperature. Therefore, research on membrane adsorption methods and the design of membrane adsorbents has significant scientific and practical value.

[0004] The core technology of membrane adsorption processes lies in the design and preparation of membrane materials. In recent years, in the search for efficient, inexpensive membrane adsorbents with strong selective adsorption, various environmentally friendly novel uranium membrane adsorption materials have been continuously developed and utilized. However, radionuclide membrane adsorption materials with high radiation resistance, strong affinity, and high selectivity are still in short supply. Summary of the Invention

[0005] In view of the above problems, this application provides a method for preparing fluorenone polymer fiber membrane composite material and its application, in order to provide a membrane composite material with high radiation resistance, strong affinity and selectivity for the effective treatment of radioactive wastewater.

[0006] To achieve the above objectives, in a first aspect of the present invention, the inventors provide a method for preparing a fluorenone polymer fiber membrane composite material, comprising the following steps:

[0007] Pretreatment steps: The leather fiber membrane is pretreated by acid washing with an emulsifier, then washed and dried to obtain the pretreated leather fiber membrane;

[0008] Modification steps: Tris(4-aminophenyl)amine, 2,7-dibromofluorenone, and the pretreated fiber membrane were added to anhydrous tetrahydrofuran. Under the action of 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, sodium tert-butoxide, sodium fluoride, and a catalyst, the mixture was heated to a certain temperature and reacted for a certain time. After centrifugation, the resulting product was washed with solvent and dried to obtain the fluorenone polymer fiber membrane composite material.

[0009] Leather fiber membranes are a renewable biomass resource derived from livestock hides. Due to their micro / nano composite and multilayer structures, they exhibit low mass transfer resistance to flowing liquids. Furthermore, the side chains of leather fiber membranes possess abundant active groups such as -COOH and -NH2, providing possibilities for chemical modification. Simultaneously, the high specific surface area and 13%-24% bound water content of leather fiber membranes enable them to rapidly transfer radiative energy to the environmental medium, thus endowing them with high radiation resistance. Despite these unique structural characteristics, leather fiber membranes lack affinity and selectivity functional groups, limiting their adsorption capacity for radioactive nuclides. Fluorenone polymers, on the other hand, are porous organic polymers. Due to their designable structure and pore size, and abundant N and O sites, they can effectively adsorb radionuclides such as uranium, cobalt, strontium, and cesium from radioactive waste liquids. Unlike existing technologies, the above technical solution uses tris(4-aminophenyl)amine with three amino coupling ends and 2,7-dibromofluorenone with bromine-terminated ends as reactant monomers, and uses a fluorenone polymer filament membrane as the substrate material to prepare a fluorenone polymer filament membrane composite material. The material preparation method of this invention is simple, rapid, green, efficient, and under mild conditions, and is easy to recycle. The prepared fluorenone polymer filament membrane composite material has porous structure and abundant N and O sites, effectively solving the problems of high mass transfer resistance, pore blockage, and membrane fouling in the adsorption of uranium (U(VI)), cobalt (Co(II)), strontium (Sr(II)), and cesium (Cs(I)) by traditional membrane materials. It also solves the problems of difficult recovery and separation of traditional powdered adsorbent materials. The resulting composite membrane material has the characteristics of fast adsorption speed, good reusability, high adsorption selectivity, and high radiation resistance.

[0010] In the pretreatment steps of some embodiments of the present invention, when the fibrous membrane is acid-washed with a demulsifier, formic acid is used to adjust the pH value to 3-4, the temperature is 36-40°C, and the time is 50-80 minutes. The demulsifier contains a degreasing agent and water in a mass ratio of 1:(700-900). When the pH value is greater than or less than this range, the demulsification effect will not achieve the expected result. When the temperature is below 36°C, the demulsification effect is poor; when the temperature is too high, it may damage the fibrous membrane structure. Through repeated experiments and comparisons, the inventors found that the fibrous membrane pretreated under the above conditions can obtain better water flux and improve reaction efficiency.

[0011] Preferably, in the modification step, (0.5-1.5) mmol of tris(4-aminophenyl)amine and (0.75-2.25) mmol of 2,7-dibromofluorenone are added per 1g of the pretreated fiber membrane. When the added tris(4-aminophenyl)amine is less than 0.5 mmol and 2,7-dibromofluorenone is less than 0.75 mmol, the adsorption performance of the fluorenone polymer fiber membrane composite material cannot achieve the expected effect; while when the added tris(4-aminophenyl)amine is greater than 1.5 mmol and 2,7-dibromofluorenone is greater than 2.25 mmol, the fluorenone polymer will block the pores of the fiber membrane, which is not conducive to adsorption.

[0012] Preferably, the reaction temperature of the modification step is 65–70°C, and the reaction time is 48–72 h. If the temperature is too low or the reaction time is too short, the reaction will be incomplete, resulting in a lower product yield.

[0013] Preferably, the catalyst in the modification step is one of bis(dibenzylacetone)palladium, tris(benzylacetone)dipalladium, or tetra(triphenylphosphine)palladium. In a more preferred embodiment, the catalyst used is bis(dibenzylacetone)palladium. The use of bis(dibenzylacetone)palladium results in better catalytic performance and a better adsorption effect on the prepared fluorene polymer fiber membrane composite material.

[0014] Preferably, the solvent used in the modification step is selected from at least one of tetrahydrofuran, chloroform, ethanol, and water. Washing the resulting reaction mixture with the above solvent can effectively remove unreacted monomers, salts, solvents, and oligomers.

[0015] In some preferred embodiments, before heating to a certain temperature during the modification step, the mixture of added tris(4-aminophenyl)amine, 2,7-dibromofluorenone, and anhydrous tetrahydrofuran is ultrasonically treated for 15–20 minutes. This ultrasonic treatment results in more uniform mixing of the materials, effectively improving reaction efficiency and yielding better products.

[0016] Preferably, in the modification step, the resulting product is washed with solvent, including at least two soaking and washing cycles, and then dried under vacuum. This washing process can more thoroughly remove impurities from the product, resulting in better adsorption performance.

[0017] In a second aspect of the invention, the inventors provide a fluorenone polymer sheath fiber membrane composite material, prepared using the preparation method described in the first aspect of the invention. This invention innovatively provides a fluorenone polymer sheath fiber membrane composite material containing numerous mesopores and macropores, predominantly mesopores. It fully leverages the structural stability, high mechanical strength, high wear resistance and flexibility, high radiation resistance, low diffusion resistance, and fast mass transfer rate of the sheath fiber membrane, as well as the synergistic effect of the abundant fluorenone groups in the fluorenone polymer. The resulting fluorenone polymer sheath fiber membrane composite material exhibits high performance adsorption of radioactive nuclides such as uranium, cobalt, strontium, and cesium, with fast adsorption speed, good reusability, high adsorption selectivity, and radiation resistance stability.

[0018] In a third aspect of the invention, the inventors provide a method for treating radioactive wastewater using a fluorenone polymer-coated fiber membrane composite material, wherein the fluorenone polymer-coated fiber membrane composite material is prepared using the preparation method described in the first aspect of the invention. The fluorenone polymer-coated fiber membrane composite material provided by the present invention exhibits low mass transfer resistance, non-clogging of mesopores and macropores, and no membrane fouling, while simultaneously solving the problems of difficult recovery and separation of traditional powdered adsorbent materials.

[0019] The above description of the invention is merely an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical solution of this application and to implement it based on the description and drawings, and to make the above-mentioned objectives and other objectives, features and advantages of this application easier to understand, the following description is provided in conjunction with the specific embodiments and drawings of this application. Attached Figure Description

[0020] The accompanying drawings are only used to illustrate the principles, implementation methods, applications, features, and effects of specific embodiments of this application and other related content, and should not be considered as limitations on this application.

[0021] In the accompanying drawings of the instruction manual:

[0022] Figure 1 These are photographs of the raw material leather fiber membrane (left) used in this invention and the fluorenone polymer leather fiber membrane composite material (right) prepared from it;

[0023] Figure 2 These are ultra-high resolution scanning electron microscope images of fluorenone polymer-fiber membrane composite materials prepared from the raw materials used in this invention, namely, CFM represents the raw material of the fiber membrane, CMPA-F@CFM represents the fluorenone polymer-fiber membrane composite material, and CMPA-F represents the fluorenone polymer.

[0024] Figure 3The infrared spectrum of the fluorenone polymer-fiber membrane composite material prepared from the raw materials used in this invention is shown.

[0025] Figure 4 This is a nitrogen adsorption-desorption curve of the fluorenone polymer-fiber membrane composite material prepared from the raw materials used in this invention: leather fiber membrane and fluorenone polymer.

[0026] Figure 5 This is a pore size distribution diagram of the fluorenone polymer-fiber membrane composite material prepared from the raw materials used in this invention: leather fiber membrane and fluorenone polymer.

[0027] Figure 6 These are the test results of the uranium adsorption effect of the fluorenone polymer fiber membrane composite material prepared in Example 3 of the present invention in solutions with different pH values;

[0028] Figure 7 These are the test results of the strontium adsorption effect of the fluorenone polymer fiber membrane composite material prepared in Example 3 of the present invention in solutions with different pH values;

[0029] Figure 8 These are the test results of the cesium adsorption effect of the fluorenone polymer fiber membrane composite material prepared in Example 3 of the present invention in solutions with different pH values;

[0030] Figure 9 These are the test results of the cobalt adsorption effect of the fluorenone polymer fiber membrane composite material prepared in Example 3 of the present invention in solutions with different pH values;

[0031] Figure 10 These are the adsorption isotherm results of the fluorenone polymer fiber membrane composite material prepared in Example 3 of this invention;

[0032] Figure 11 These are the adsorption kinetics results of the fluorenone polymer fiber membrane composite material prepared in Example 3 of this invention;

[0033] Figure 12 This is the result of mixed competitive adsorption of the fluorenone polymer fiber membrane composite material prepared in Example 3 of the present invention;

[0034] Figure 13 This is the result of the coexistence ion adsorption effect of the fluorenone polymer skin fiber membrane composite material prepared in Example 3 of the present invention;

[0035] Figure 14 This is the result of repeated use of the fluorenone polymer fiber membrane composite material prepared in Example 3 of the present invention;

[0036] Figure 15 The infrared spectra of the fluorenone polymer fiber membrane composite material prepared in Example 3 of this invention before and after uranium adsorption are shown. Detailed Implementation

[0037] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0038] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0039] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0040] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0041] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0042] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0043] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0044] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0045] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0046] Existing adsorbents used for treating radioactive waste liquids suffer from drawbacks such as high mass transfer resistance, poor radiation resistance, weak affinity and selectivity for radionuclides, and difficulty in separating and recovering powdered adsorbent materials. Therefore, it is necessary to develop a composite membrane material more suitable for radioactive waste liquid treatment. Fluorine fiber membranes are an excellent membrane structure substrate material. The inventors have been actively exploring the feasibility and effectiveness of loading highly efficient and specifically radionuclide-affinity polymer molecules onto these membranes to solve the aforementioned problems. Furthermore, the fluorene ketone polymer-fiber membrane composite material has macropores and mesopores that are less prone to clogging, which is expected to improve the adsorption efficiency and reusability of radionuclides. Based on this, this invention provides a fluorene ketone polymer-fiber membrane composite material, its preparation method, and its applications. The prepared fluorenone polymer sheath fiber membrane composite material not only possesses the characteristic of abundant N and O sites of fluorenone polymer, but the introduced fluorenone groups can also improve its adsorption performance for uranium (U(VI)), cobalt (Co(II)), strontium (Sr(II)) and cesium (Cs(I)). At the same time, it also has the characteristics of low diffusion resistance, fast mass transfer rate and radiation resistance of sheath fiber membrane.

[0047] The collagen fiber membrane (CFM) used in this invention is the remaining layer of leather after tanning cowhide and splitting to obtain the top-grain leather. As an inexpensive raw material, collagen fiber membrane is hydrophilic but insoluble in water, maintaining structural stability in organic wastewater. It possesses unique properties such as high mechanical strength, high abrasion resistance, and flexibility. Furthermore, the 13%-24% bound water in the collagen fiber membrane promotes the rapid transfer of radiative energy to the environmental medium, thus exhibiting high radiation resistance. In addition, as an important component of animal skin, the collagen fiber membrane's collagen molecule side chains contain abundant functional groups (such as -COOH, -NH2, and -OH), providing various possibilities for its modification. Simultaneously, the collagen fiber membrane itself is fibrous, with adsorption sites located on the fiber surface, exhibiting characteristics such as low diffusion resistance and rapid mass transfer.

[0048] The main concept of the present invention will now be explained through the following specific embodiments.

[0049] Unless otherwise specified, the reagents, instruments, and measurement methods used in this invention are all reagents, instruments, and measurement methods well known to those skilled in the art.

[0050] Example 1

[0051] Preparation method and application of fluorenone polymer fiber membrane composite material

[0052] The fibrous membrane was first acid-washed with a deemulsifier (common degreasing agent and water in a mass ratio of 1:700), and the pH of the reaction system was adjusted to 3.2 with formic acid. The washing was carried out at 40°C for 60 min to obtain the pretreated fibrous membrane. 0.5 mmol of sodium fluoride, 0.045 mmol of 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenylXPhos, 0.03 mmol of bis(di-benzylacetone)palladium Pd(dba)2, 3.5 mmol of sodium tert-butoxide NaOtBu, and 1 g of the pretreated fibrous membrane (labeled CFM) were added to a 250 mL Schlenk tube, and the reaction system was placed under a nitrogen atmosphere. Subsequently, 0.5 mmol of tris(4-aminophenyl)amine and 0.75 mmol of 2,7-dibromofluorenone were added to 30 mL of anhydrous tetrahydrofuran, and the mixture was sonicated for 15 min to obtain a mixed solution. The above mixed solution was injected into a Schlenk tube containing a pretreated fiber membrane, heated to 67°C and stirred for 48 hours. The resulting product was filtered and washed with chloroform, ethanol and other solutions, and then vacuum dried to obtain the fluorenone polymer fiber membrane composite material.

[0053] Example 2

[0054] Preparation methods and applications of fluorenone polymer fiber membrane composites

[0055] The fibrous membrane was first acid-washed with a deemulsifier (common degreasing agent and water in a mass ratio of 1:800), adjusting the pH of the reaction system to 3.2, and acid-washed at 40℃ for 60 min to obtain the pretreated fibrous membrane. 0.75 mmol sodium fluoride, 0.07 mmol XPos, 0.05 mmol Pd(dba)2, 5.3 mmol NaOtBu, and 1 g of the pretreated fibrous membrane were added to a 250 mL Schlenk tube and placed under a nitrogen atmosphere. Subsequently, 0.75 mmol tris(4-aminophenyl)amine and 1.13 mmol 2,7-dibromofluorenone were added to 37.5 mL anhydrous tetrahydrofuran, and the mixture was sonicated for 15 min. The above solution was injected into a Schlenk tube, heated to 67℃, and stirred for 48 h. The resulting product was filtered, washed with chloroform and ethanol solutions, and vacuum dried to obtain the fluorenone polymer fibrous membrane composite material. The morphology of the prepared fluorenone polymer skin fiber membrane composite material was observed using an ultra-high resolution scanning electron microscope. The abundant fibers on the skin fiber membrane were intertwined, and the fiber surface was rough with many stacked spherical particles.

[0056] Example 3

[0057] The fibrous membrane was first acid-washed with a deemulsifier (common degreasing agent and water in a mass ratio of 1:900), adjusting the pH of the reaction system to 3.2, and acid-washed at 40℃ for 60 min to obtain the pretreated fibrous membrane. 1 mmol of sodium fluoride, 0.09 mmol of XPhos, 0.06 mmol of Pd(dba)2, 7 mmol of NaOtBu, and 1 g of the pretreated fibrous membrane were added to a 250 mL Schlenk tube and placed under a nitrogen atmosphere. Subsequently, 1 mmol of tris(4-aminophenyl)amine and 1.5 mmol of 2,7-dibromofluorenone were added to 50 mL of anhydrous tetrahydrofuran, and the mixture was sonicated for 15 min. The above solution was injected into a Schlenk tube, heated to 67℃, and stirred for 48 h. The resulting product was filtered, washed with chloroform and ethanol solutions, and vacuum dried to obtain the fluorenone polymer fibrous membrane composite material.

[0058] Please see Figure 1 The images shown are of the raw material skin fiber membrane used in this invention and the prepared fluorenone polymer skin fiber membrane composite material. Please refer to [the images for further details]. Figure 2 The image shown is a morphological image of the prepared fluorenone polymer-fiber membrane composite material observed using an ultra-high resolution scanning electron microscope. From... Figure 1 As can be seen from the two images on the left and right, the shape and size of the raw fibrous membrane remain almost unchanged before and after processing, but the resulting fluorenone polymer fibrous membrane composite material is darker in color than the raw fibrous membrane. Figure 2 In this text, CMPA-F represents fluorenone polymer, CFM represents fiber membrane, and CMPA-F@CFM represents the prepared fluorenone polymer-fiber membrane composite material. The fluorenone polymer consists of stacked small spherical particles, thus requiring a higher magnification for observation. Figure 2 The results show that the fluorenone polymer fiber membrane composite has abundant intertwined fibers with a rough fiber surface and many stacked spherical particles. Figure 3 The images of the raw material for the fluorenone membrane and the infrared spectra of the prepared fluorenone polymer fluorenone membrane composite material show that, compared to the raw material, the FTIR spectrum of the fluorenone polymer fluorenone membrane composite material is significantly better at 816 cm⁻¹. -1 1312cm -1 1501cm -1 3281cm -1 The appearance of new absorption peaks at these four locations, which correspond to the groups contained in the fluorenone polymers such as aromatic rings, tertiary amines, and aniline, respectively, indicates the successful loading of fluorenone polymers onto the fiber membrane, thus confirming the successful synthesis of the fluorenone polymer fiber membrane composite material.

[0059] Figure 4This is a nitrogen adsorption-desorption curve of the raw material used in this invention, the fluorenone polymer, and the fluorenone polymer-fiber membrane composite material prepared in Example 3. The results show that all the prepared materials exhibit V-shaped nitrogen adsorption-desorption isotherms, indicating the presence of a large number of mesopores and macropores.

[0060] Figure 5 This is a pore size distribution diagram of the raw materials used in this invention: a fibrous membrane, fluorenone polymer, and the fluorenone polymer fibrous membrane composite material prepared in Example 3. The results show that the pore sizes of the prepared materials are concentrated in the range of 2.5–7 nm, which proves that the pore type of the fluorenone polymer fibrous membrane composite material is mainly mesoporous.

[0061] Example 4

[0062] Fluorenone polymer fiber membrane composite material and its preparation method

[0063] The fibrous membrane was first acid-washed with a deemulsifier (common degreasing agent and water in a mass ratio of 1:900), adjusting the pH of the reaction system to 3.2, and acid-washed at 40℃ for 60 min to obtain the pretreated fibrous membrane. 1.5 mmol sodium fluoride, 0.135 mmol XPhos, 0.09 mmol Pd(dba)2, 10.5 mmol NaOtBu, and 1 g of the pretreated fibrous membrane were added to a 250 mL Schlenk tube and placed under a nitrogen atmosphere. Then, 1.5 mmol tris(4-aminophenyl)amine and 2.25 mmol 2,7-dibromofluorenone were added to 75 mL tetrahydrofuran, and the mixture was sonicated for 15 min. The above solution was injected into a Schlenk tube, heated to 67℃, and stirred for 48 h. The resulting product was filtered, washed with chloroform and ethanol solutions, and vacuum dried to obtain the fluorenone polymer fibrous membrane composite material.

[0064] Example 5

[0065] Fluorenone polymer fiber membrane composite material and its preparation method

[0066] The fibrous membrane was first acid-washed with a deemulsifier (common degreasing agent and water in a mass ratio of 1:900), adjusting the pH of the reaction system to 3.9, and acid-washed at 36℃ for 80 min to obtain the pretreated fibrous membrane. 1.5 mmol sodium fluoride, 0.135 mmol XPhos, 0.09 mmol Pd(dba)2, 10.5 mmol NaOtBu, and 1 g of the pretreated fibrous membrane were added to a 250 mL Schlenk tube and placed under a nitrogen atmosphere. Subsequently, 1.0 mmol tris(4-aminophenyl)amine and 2.0 mmol 2,7-dibromofluorenone were added to 70 mL tetrahydrofuran, and the mixture was sonicated for 15 min. The above solution was injected into a Schlenk tube, heated to 67℃, and stirred for 48 h. The resulting product was filtered, washed with chloroform and ethanol solutions, and vacuum dried to obtain the fluorenone polymer fibrous membrane composite material.

[0067] Example 6

[0068] Preparation methods and applications of fluorenone polymer fiber membrane composites

[0069] The fibrous membrane was first acid-washed with a deemulsifier (common degreasing agent and water in a mass ratio of 1:900), adjusting the pH of the reaction system to 3.2, and acid-washed at 40℃ for 60 min to obtain the pretreated fibrous membrane. 1 mmol of sodium fluoride, 0.09 mmol of XPos, 0.06 mmol of Pd2(dba)3, 7 mmol of NaOtBu, and 1 g of the pretreated fibrous membrane were added to a 250 mL Schlenk tube and placed under a nitrogen atmosphere. Subsequently, 1 mmol of tris(4-aminophenyl)amine and 1.5 mmol of 2,7-dibromofluorenone were added to 50 mL of anhydrous tetrahydrofuran, and the mixture was sonicated for 15 min. The above solution was injected into a Schlenk tube, heated to 67℃, and stirred for 48 h. The resulting product was filtered, washed with chloroform and ethanol solutions, and vacuum dried to obtain the fluorenone polymer fibrous membrane composite material.

[0070] Applications in the adsorption of radionuclides:

[0071] 0.01 g of the fluorenone polymer fiber membrane composite material prepared in Example 6 was added to 10 mL of 50 mg / L aqueous solutions of U(VI), Sr(II), Co(II), and Cs(I), respectively, and adsorbed for 24 h at 25 °C and a shaking speed of 180 rpm. The prepared fluorenone polymer fiber membrane composite material achieved a removal rate of over 80% for all reflective nuclides.

[0072] Example 7

[0073] Preparation methods and applications of fluorenone polymer fiber membrane composites

[0074] The fibrous membrane was first acid-washed with a deemulsifier (common degreasing agent and water in a mass ratio of 1:900), adjusting the pH of the reaction system to 3.2, and acid-washed at 40℃ for 60 min to obtain the pretreated fibrous membrane. 1 mmol of sodium fluoride, 0.09 mmol of XPhos, 0.06 mmol of Pd(PPh3)4, 7 mmol of NaOtBu, and 1 g of the pretreated fibrous membrane were added to a 250 mL Schlenk tube and placed under a nitrogen atmosphere. Then, 1 mmol of tris(4-aminophenyl)amine and 1.5 mmol of 2,7-dibromofluorenone were added to 50 mL of anhydrous tetrahydrofuran, and the mixture was sonicated for 15 min. The above solution was injected into a Schlenk tube, heated to 67℃, and stirred for 48 h. The resulting product was filtered, washed with chloroform and ethanol solutions, and vacuum dried to obtain the fluorenone polymer fibrous membrane composite material.

[0075] Applications in the adsorption of radionuclides:

[0076] 0.01 g of the fluorenone polymer fiber membrane composite material prepared in Example 7 was added to 10 mL of 50 mg / L aqueous solutions of U(VI), Sr(II), Co(II), and Cs(I), respectively, and adsorbed for 24 h at 25 °C and a shaking speed of 180 rpm. The prepared fluorenone polymer fiber membrane composite material achieved a removal rate of over 80% for all reflective nuclides.

[0077] Example 8

[0078] Application of fluorenone polymer fiber membrane composites in the adsorption of radionuclides

[0079] 0.01 g of the fluorenone polymer fiber membrane composite material sample prepared in Example 3 was added to 10 mL of 50 mg / L aqueous solutions of U(VI), Sr(II), Co(II), and Cs(I), respectively, and adsorbed for 24 h at 25 °C and a shaking speed of 180 rpm. The experimental results are shown in Table 1. The prepared fluorenone polymer fiber membrane composite material achieved a removal rate of over 90% for all reflective nuclides.

[0080] Table 1. Adsorption effects of the fluorenone polymer fiber membrane composite material prepared in Example 3 on U(VI), Sr(II), Co(II), and Cs(I).

[0081]

[0082] Example 9

[0083] The effect of pH value on adsorption experiments

[0084] 0.01 g of the fluorenone polymer fiber membrane composite sample prepared in Example 3 was added to 10 mL and 20 mg / L aqueous solutions of U(VI), Sr(II), Co(II), and Cs(I) at different pH values ​​(pH 2-9), respectively. Adsorption was carried out at 25 °C and a shaking speed of 180 rpm for 24 h. The results are as follows: Figure 6 , Figure 7 , Figure 8 and Figure 9 As shown in the figure, the optimal adsorption pH is 7.

[0085] Example 10

[0086] Adsorption isotherm experiment

[0087] 0.01 g of the fluorenone polymer fiber membrane composite sample prepared in Example 3 was added to 20 mL of U(VI), Sr(II), Co(II), and Cs(I) aqueous solutions at 0-300 mg / L and pH=7. Adsorption was carried out for 24 h at 25-45 °C and a shaking speed of 180 rpm. The results are as follows. Figure 10 As shown in Table 2, the maximum adsorption capacities of fluorenone polymer fiber membrane composites for U(VI), Sr(II), Co(II), and Cs(I) calculated by the Langmuir model are 322.6 mg / g, 88.5 mg / g, 97.6 mg / g, and 145.1 mg / g, respectively.

[0088] Table 2. Langmuir and Freundlich parameters for fitting the adsorption of U(VI), Sr(II), Co(II), and Cs(I) in fluorenone polymer-fiber membrane composites.

[0089]

[0090] Example 11

[0091] Adsorption kinetics experiment

[0092] 0.01 g of the fluorenone polymer fiber membrane composite sample prepared in Example 3 was added to 10 mL of 50 mg / L aqueous solutions of U(VI), Sr(II), Co(II), and Cs(I) at pH 7. Adsorption was carried out at 25 °C and a shaking speed of 180 rpm for 24 h. The results are as follows. Figure 11 As shown in Table 3, the fluorenone polymer fiber membrane composite material reached adsorption equilibrium at 60 min, 40 min, 60 min, and 40 min, respectively.

[0093] Table 3. Kinetic fitting parameters for the adsorption of U(VI), Sr(II), Co(II), and Cs(I) by fluorenone polymer fiber membrane composite material.

[0094]

[0095] Example 12

[0096] Mixed competition experiment

[0097] 0.01 g of the fluorenone polymer fiber membrane composite sample prepared in Example 3 was added to 10 mL of UO2 solution at 50 mg / L and pH = 7. 2+ K + Na + Mg 2+ Ca 2+ Co 2+ and Cu 2+ In a mixed metal solution, adsorption was performed for 24 hours at 25°C and a shaking speed of 180 rpm. The results are as follows: Figure 12 As shown, the fluorenone polymer fiber membrane composite exhibits resistance to UO2 in a mixed metal solution. 2+ It exhibits high adsorption selectivity (77%).

[0098] Example 13

[0099] Effects of coexisting ions

[0100] 0.01 g of the fluorenone polymer fiber membrane composite sample prepared in Example 3 was added to 10 mL of UO2 solution at 50 mg / L and pH = 7. 2+ In aqueous solutions, coexisting ions (K+) at different concentrations (0-5000 mg / L) were added. + Na + Mg 2+ Ca 2+ Cu 2+ F - NO3 - SO4 2- Cl - The adsorption was carried out at 25℃ and a shaking speed of 180 rpm for 24 hours. The results are as follows. Figure 13 As shown, with the ion concentration increasing from 0 to 5000 mg / L, Na + K + Co 2+ Ca 2+ With UO2 2+ Coexistence with UO2 2+ The adsorption capacity was minimally affected, and the extraction rates were all greater than 85%, while Cu 2+ and Mg 2+The weakening effect on the adsorption capacity of fluorenone polymer-coated fiber membrane composites is significant, which is attributed to Cu 2+ and Mg 2+ It can bind to the active sites on fluorenone polymer fiber membrane composites to generate UO2. 2+ Adsorption competition.

[0101] Example 14

[0102] Reusability test

[0103] 0.01 g of the fluorenone polymer fiber membrane composite sample prepared in Example 3 was added to 10 mL of a 50 mg / L U(VI) aqueous solution (pH = 7), and adsorption was performed for 24 h at 25 °C and a shaking speed of 180 rpm. The material was recovered after sampling with a syringe, and uranyl ions adsorbed on the fluorenone polymer fiber membrane composite were eluted with 10 mL of dilute HNO3 (0.1 mol / L). The adsorbent was then regenerated with 10 mL of NaOH (pH = 9) to repeat the adsorption of uranium. The results are as follows... Figure 14 As shown in the figure, after five regeneration cycles, the fluorenone polymer fiber membrane composite material exhibits improved performance in terms of UO2. 2+ It can still maintain a removal efficiency of 77%, indicating that it has good reusability.

[0104] Fourier transform infrared spectroscopy (FTIR) was used to study the adsorption of UO2 on fluorenone polymer fiber membrane composites. 2+ Before and after testing and analysis (FTIR test results can be found in [link]). Figure 15 The results showed that in the U spectrum of the fluorenone polymer-fiber membrane composite, at 909 cm⁻¹... -1 A new absorption peak was found at [O=U VI =O] absorption peak, indicating UO2 2+ It was successfully adsorbed onto the fluorenone polymer-coated fiber membrane composite material. In the spectral analysis of the adsorbed sample, the adsorption point is located at 1500 cm⁻¹. -1 The absorption peaks nearby are significantly weakened, indicating that -NH- is involved in the chemical reaction.

[0105] Comparative Example 1

[0106] Fluorenone polymers, their preparation methods and uses

[0107] Fluorenone polymers were prepared using tri(4-aminophenyl)amine and 2,7-dibromofluorenone as monomers in the presence of 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, sodium tert-butoxide, sodium fluoride, bis(di-benzylacetone)palladium catalyst, and anhydrous tetrahydrofuran as solvent.

[0108] Applications in the adsorption of radionuclides:

[0109] 0.01 g of the fluorenone polymer sample prepared in Comparative Example 1 was added to 10 mL of 50 mg / L aqueous solutions of U(VI), Sr(II), Co(II), and Cs(I), respectively, and adsorbed for 24 h at 25 °C and a shaking speed of 180 rpm. The experimental results are shown in Table 4. The results indicate that the fluorenone polymer prepared in Comparative Example 1 achieved a removal rate of over 30% for all reflective nuclides.

[0110] Table 4. Adsorption effects of fluorenone polymers on U(VI), Sr(II), Co(II), and Cs(I)

[0111]

[0112] In summary, the fluorenone polymer sheath fiber membrane composite material prepared by this invention is a membrane composite material that integrates the abundant fluorenone groups, aromatic rings, tertiary amines, and aniline groups of the fluorenone polymer with the flexibility and stability of the numerous mesopores of the sheath fiber membrane. It exhibits a strong adsorption capacity for target metal ions in radioactive wastewater. Since it avoids problems such as pore blockage and membrane fouling, the fluorenone polymer sheath fiber membrane composite material is reusable and has strong radiation resistance, making it worthy of widespread industrial application.

[0113] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A method for preparing a fluorenone polymeric skin fiber membrane composite material, characterized by, The method comprises the following steps: A pretreatment step: pretreating the skin fiber membrane with a defoaming acid pickling agent, washing and drying to obtain a pretreated skin fiber membrane; A modification step: adding tris(4-aminophenyl)amine, 2,7-dibromofluorenone and the pretreated skin fiber membrane into anhydrous tetrahydrofuran, and under the action of 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, sodium tert-butoxide, sodium fluoride and a catalyst, the mixture is heated to a certain temperature and reacted for a certain time, then centrifuged, and the obtained product is washed with a solvent and dried to obtain the fluorenone polymer skin fiber membrane composite material.

2. The production method according to claim 1, characterized by, In the pretreatment step, formic acid is used to adjust the pH value to 3-4, the temperature is 36-40℃, and the time is 50-80 min, and the defoaming agent comprises a mass ratio of 1: (700-900) of a degreasing agent and water.

3. The preparation method according to claim 1, characterized in that, In the modification step, the amount of tris(4-aminophenyl)amine and 2,7-dibromofluorenone added is (0.5-1.5) mmol and (0.75-2.25) mmol per 1 g of the pretreated skin fiber membrane.

4. The production method according to claim 1, characterized by, The reaction temperature of the modification step is 65-70℃, and the reaction time is 48-72 h.

5. The preparation method according to claim 1, characterized in that, The catalyst of the modification step is one of bis(diphenylphosphino) palladium, tris(dibenzylideneacetone) dipalladium and tetrakis(triphenylphosphine) palladium.

6. The method of claim 1, wherein, The solvent of the modification step is at least one or more selected from tetrahydrofuran, chloroform, ethanol and water.

7. The preparation method according to claim 1, characterized in that, In the modification step, before heating to a certain temperature, the mixture of added tris(4-aminophenyl)amine, 2,7-dibromofluorenone and anhydrous tetrahydrofuran is subjected to ultrasonic treatment for 15-20 min.

8. The method of claim 1, wherein, In the modification step, the washing of the obtained product with a solvent comprises at least two or more times of soaking and washing, and the drying is performed in a vacuum environment.

9. A fluorenone polymeric fiber membrane composite material characterized by, The method is prepared by any one of claims 1-8.

10. Treatment of radioactive waste water with a fluorenone polymer skin fiber membrane composite material, characterized in that, The fluorenone polymer skin fiber membrane composite material is prepared by any one of claims 1-8.

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