A PAN-based electrospun uranium adsorption membrane and a preparation method and application thereof

Abstract

The application discloses a PAN-based electrospun uranium adsorption membrane and a preparation method and application thereof, and relates to the technical field of uranium resource recovery and wastewater treatment such as seawater, salt lake brine and uranium mine wastewater. The preparation method comprises the following steps: PAN-based spinning solution and two kinds of monomer solutions are respectively loaded into three injectors of an electrospun spinning device, then electrospinning is performed to make the two kinds of monomer solutions and the PAN-based spinning solution spin together to obtain a nascent electrospun membrane; the two kinds of monomer solutions are amino monomer solution and aldehyde group monomer solution, and the molar ratio of the amino monomer and the aldehyde group monomer is 1:1; the nascent electrospun membrane is sprayed with acetic acid to wet the membrane surface, then heat pressing treatment is performed to obtain the PAN-based electrospun uranium adsorption membrane. The process of spinning the PAN-based spinning solution and the two kinds of monomer solutions together is adopted, so that nano-pore channels exist on the PAN-based electrospun uranium adsorption membrane, and COF adsorbent is uniformly loaded on the surface of the nanofiber.

Description

Technical Field

[0001] This invention relates to the field of uranium resource recovery and wastewater treatment, including seawater / salt lake brine and uranium mine wastewater, and particularly to a PAN-based electrospun uranium adsorption membrane, its preparation method, and its application. Background Technology

[0002] With the widespread application of nuclear energy in energy, medicine, scientific research, and other fields, the amount of nuclear wastewater generated is increasing year by year. The uranium it contains is not only radioactive but also poses a serious threat to the ecological environment and human health. Meanwhile, uranium is an important strategic resource, and the recovery of uranium from nuclear wastewater or uranium-containing water bodies also has significant economic value. Therefore, developing efficient, stable, and environmentally friendly uranium adsorbent materials has become a key research focus.

[0003] Currently, commonly used uranium adsorption materials include activated carbon, ion exchange resins, metal-organic frameworks (MOFs), and electrospun membranes. Among these, electrospun membranes show promising application prospects in the adsorption field due to their advantages such as large specific surface area, high porosity, abundant adsorption sites, and recyclability. However, existing electrospun membranes are mostly modified using single or a few functional monomers, resulting in problems such as low adsorption capacity, poor selectivity, and unsatisfactory recyclability, making it difficult to meet the requirements for efficient uranium adsorption in practical applications.

[0004] Therefore, there is a need to provide a new electrospun PAN-based membrane for uranium adsorption. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a PAN-based electrospun uranium adsorption membrane, its preparation method, and its application. The synergistic effect of the amino groups and BTZ-type groups in the PAN-based electrospun uranium adsorption membrane significantly improves the adsorption capacity and selectivity of the membrane material for uranium ions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a PAN-based electrospun uranium adsorption membrane includes the following steps:

[0008] The PAN-based spinning solution and two monomer solutions were respectively loaded into three syringes of the electrospinning equipment, and then electrospinning was performed to allow the two monomer solutions and the PAN-based spinning solution to be synergistically spun to obtain a nascent electrospun film; the two monomer solutions were an amino monomer solution and an aldehyde monomer solution, and the molar ratio of the amino monomer in the amino monomer solution to the aldehyde monomer in the aldehyde monomer solution was 1:1.

[0009] The nascent electrospun membrane is wetted with acetic acid and then subjected to hot pressing to obtain the PAN-based electrospun uranium adsorption membrane.

[0010] The PAN-based spinning solution is obtained by dissolving PAN in a solvent, and the mass concentration of polyacrylonitrile in the PAN-based spinning solution is 16-18 wt%.

[0011] The solvents for the PAN-based spinning solution and the two monomer solutions are one or more of methanol, acetone, o-dichlorobenzene, DMSO, and DMF.

[0012] The amino monomer is at least one of 3,5-diamino-2-hydroxybenzoic acid, 2,5-diaminobenzenesulfonic acid, 2,5-diaminobenzonitrile, 2,5-diaminophenol, 2,5-diamino-1,4-dihydroxybenzene dihydrochloride, 3,5-diaminophenol, and 2,5-diaminophenylphosphine.

[0013] The aldehyde monomer is an aldehyde compound derived from benzothiadiazole.

[0014] The aldehyde monomer is 4,4-(benzo[c][1,2,5]thiadiazole-4,7-dimethyl)dibenzaldehyde.

[0015] The electrospinning parameters are as follows: spinning voltage of 18-20 kV, spinning distance of 18-20 cm, feed speed of 0.07-0.09 mm / min, ambient temperature of 20-30 ℃, and relative humidity of 30%-50%.

[0016] The hot pressing temperature is 80~100 ℃, the hot pressing time is 2~3 h, and the hot pressing pressure is 0.4~0.5 MPa.

[0017] A PAN-based electrospun uranium adsorption membrane is prepared using the above-mentioned method for preparing PAN-based electrospun uranium adsorption membranes.

[0018] The PAN-based electrospun uranium adsorption membrane has nanopores on its nanofibers, which form an interwoven three-dimensional network structure, and a COF-like adsorbent is uniformly loaded on the surface of the nanofibers.

[0019] The above-mentioned PAN-based electrospun uranium adsorption membrane is used in the field of uranium adsorption.

[0020] The PAN-based electrospun uranium adsorption membrane is used under the condition that the pH value is 3-6.

[0021] The beneficial effects of this invention are as follows:

[0022] (1) The present invention adopts a process of synergistic spinning of PAN-based spinning solution and two monomer solutions, so that there are nanopores on the PAN-based electrospun uranium adsorption membrane, and the nanofiber distribution of the PAN-based electrospun uranium adsorption membrane has good uniformity. The COF-like adsorbent is uniformly loaded on the surface of the nanofiber through interfacial interaction.

[0023] (2) This invention innovatively introduces a variety of amino monomers and benzothiadiazole (BTZ) aldehyde monomers into PAN electrospun membranes. The synergistic effect of amino groups and BTZ groups significantly improves the adsorption capacity and selectivity of membrane materials for uranium ions, solving the problems of low adsorption efficiency and poor selectivity of existing electrospun adsorption membranes.

[0024] (3) The present invention uses electrospinning to prepare adsorption membranes. The process is simple and easy to operate, and continuous production can be achieved. Moreover, no toxic or harmful reagents are used in the preparation process, making it green and environmentally friendly and suitable for industrial promotion.

[0025] (4) The PAN-based electrospun uranium adsorption membrane prepared by the present invention has good physicochemical stability and recyclability. It can be used not only for the treatment of nuclear wastewater, but also for the recovery of uranium resources in seawater, salt lakes and other water bodies, and has broad application prospects. Attached Figure Description

[0026] Figure 1 This is a microstructure diagram of the PAN-based electrospun uranium adsorption membrane prepared in Example 1 of the present invention.

[0027] Figure 2 This is a microstructure diagram of the PAN-based electrospun uranium adsorption membrane prepared in Example 2 of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0029] Unless otherwise specified, all pharmaceutical agents used in the embodiments of this invention are commercially available.

[0030] Example 1:

[0031] Part 1: Preparation of PAN-based electrospun uranium adsorption membrane.

[0032] In this embodiment, PAN was dissolved using DMF at a concentration of 16 wt%.

[0033] An amino monomer solution was obtained by dissolving 0.098 mmol of 2,5-diaminobenzenesulfonic acid in a mixed solvent of 5 mL methanol and 5 mL DMSO / DMF.

[0034] Weigh 0.098 mmol of 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde monomer and dissolve it in a mixed solvent of 5 mL o-dichlorobenzene and 5 mL DMSO to obtain an aldehyde monomer solution.

[0035] Co-spinning was performed with a spinning injection speed of 0.07 mm / min, a voltage of 18 KV, a spinning distance of 18 cm, a solvent needle of size 22, a spinning solution needle of size 18, a monomer injection of 2.9 mL, and a spinning time of 8 h.

[0036] The membrane surface was sprayed with 6 mol / L acetic acid (HoAC) and then placed in a drying oven for hot pressing. The hot pressing was carried out using a double-layer copper heating plate at a temperature of 80℃ for 2 h to obtain a PAN-based electrospun uranium adsorption membrane.

[0037] Figure 1 This is a microscopic image of the PAN-based electrospun uranium adsorption membrane prepared in this embodiment. From... Figure 1 As can be seen, the electrospun membrane can be loaded with functional groups to adsorb uranium on its uniform spun fibers.

[0038] Part Two: Uranium Adsorption Experiment.

[0039] A 500 ppb aqueous solution of uranyl nitrate (MW: 502.13, purity 99%) was prepared using ultrapure water. The pH of the uranyl nitrate aqueous solution was adjusted to 3 and 5 using 1.0 mol / L HCl and 1.0 mol / L Na₂CO₃ solutions, respectively. An adsorption membrane with a surface area of ​​30 × 15 cm⁻¹ was then added to a brown glass bottle. The experiment was conducted by placing the brown glass bottle in a shaker at 120 rpm for half an hour. Samples were then taken, and the uranium concentration was determined using ICP-MS.

[0040] The uranium adsorption effect is shown in Table 1:

[0041] Table 1. Uranium adsorption experimental results of the PAN-based electrospun uranium adsorption membrane prepared in Example 1

[0042]

[0043] As can be seen, the adsorption membrane has an adsorption rate of over 80% for uranium, and after five cycles, the removal rate still reaches over 75%. This method can achieve the recovery of uranium.

[0044] Example 2:

[0045] Part 1: Preparation of PAN-based electrospun uranium adsorption membrane.

[0046] In this embodiment, PAN was dissolved using DMF at a concentration of 18 wt%.

[0047] A 0.098 mmol 2,5-diaminophenol solution was obtained by dissolving 0.098 mmol of 2,5-diaminophenol in a mixed solvent of 5 mL methanol and 5 mL DMSO / DMF.

[0048] Weigh 0.098 mmol of 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde monomer and dissolve it in a mixed solvent of 5 mL o-dichlorobenzene and 5 mL DMSO to obtain an aldehyde monomer solution.

[0049] Co-spinning was performed with a spinning injection speed of 0.09 mm / min, a voltage of 20 kV, a spinning distance of 20 cm, a solvent needle of size 22, a spinning solution needle of size 18, a monomer injection of 2.9 mL, and a spinning time of 8 h.

[0050] The membrane surface was sprayed with 6 mol / L acetic acid (HoAC) and then placed in a drying oven for hot pressing at 100℃ for 3 h to obtain a PAN-based electrospun uranium adsorption membrane.

[0051] Figure 2 This is a microstructure characterization image of the PAN-based electrospun uranium adsorption membrane prepared in Example 2. Figure 2 As can be seen, the nanofibers in the adsorption membrane exhibit an interwoven three-dimensional network structure with excellent uniformity in fiber distribution. The in-situ synthesized COF-like adsorbent is uniformly loaded onto the fiber surface through interfacial interactions, without significant agglomeration. In summary, the prepared uranium adsorption membrane possesses excellent morphological characteristics such as high specific surface area, hierarchical pore structure, and uniform distribution of functional sites, laying a structural foundation for improving its uranium adsorption performance.

[0052] Part Two: Uranium Adsorption Experiment.

[0053] A 500 ppb aqueous solution of uranyl nitrate (MW: 502.13, purity 99%) was prepared using ultrapure water. The pH of the uranyl nitrate aqueous solution was adjusted to 3 and 5 using 1.0 mol / L HCl and 1.0 mol / L Na₂CO₃ solutions, respectively. An adsorption membrane with a surface area of ​​30 × 15 cm⁻¹ was then added to a brown glass bottle. The experiment was conducted by placing the brown glass bottle in a shaker at 120 rpm for half an hour. Samples were then taken, and the uranium concentration was determined using ICP-MS.

[0054] The uranium adsorption effect is shown in Table 2:

[0055] Table 2. Uranium adsorption experimental results of the PAN-based electrospun uranium adsorption membrane prepared in Example 2.

[0056]

[0057] As can be seen, the adsorption membrane achieves an adsorption rate of over 95% for uranium, and even after five cycles, the removal rate remains above 90%. This method enables highly efficient recovery of uranium and has broad application prospects.

[0058] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0059] The parts of this invention not described in detail are well-known in the art. The above embodiments are provided merely for the purpose of describing the invention and are not intended to limit the scope of the invention. The scope of the invention is defined by the appended claims. All equivalent substitutions and modifications made without departing from the spirit and principles of the invention should be covered within the scope of the invention.

Claims

1. A method for preparing a PAN-based electrospun uranium adsorption membrane, characterized in that, Includes the following steps: The PAN-based spinning solution and two monomer solutions were respectively loaded into three syringes of the electrospinning equipment, and then electrospinning was performed to allow the two monomer solutions and the PAN-based spinning solution to be synergistically spun to obtain a nascent electrospun film; the two monomer solutions were an amino monomer solution and an aldehyde monomer solution, and the molar ratio of the amino monomer in the amino monomer solution to the aldehyde monomer in the aldehyde monomer solution was 1:

1. The nascent electrospun membrane was sprayed with acetic acid and then subjected to hot pressing to obtain the PAN-based electrospun uranium adsorption membrane; the hot pressing temperature was 80~100 ℃, the hot pressing time was 2~3 h, and the hot pressing pressure was 0.4~0.5 MPa. The PAN-based spinning solution is obtained by dissolving PAN in a solvent, and the mass concentration of polyacrylonitrile in the PAN-based spinning solution is 16~18 wt%; the amino monomer is at least one of 3,5-diamino-2-hydroxybenzoic acid, 2,5-diaminobenzenesulfonic acid, 2,5-diaminobenzonitrile, 2,5-diaminophenol, 2,5-diamino-1,4-dihydroxybenzene dihydrochloride, 3,5-diaminophenol, and 2,5-diaminophenylphosphine; the aldehyde monomer is 4,4-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde.

2. The method for preparing PAN-based electrospun uranium adsorption membrane according to claim 1, wherein the solvent of the PAN-based spinning solution and the two monomer solutions is one or more of methanol, acetone, o-dichlorobenzene, DMSO and DMF.

3. The method for preparing a PAN-based electrospun uranium adsorption membrane according to claim 1 or 2, characterized in that, The electrospinning parameters are: spinning voltage of 18-20 kV, spinning distance of 18-20 cm, feed speed of 0.07-0.09 mm / min, ambient temperature of 20-30 ℃, and relative humidity of 30%-50%.

4. A PAN-based electrospun uranium adsorption membrane, characterized in that, It is prepared by the method for preparing PAN-based electrospun uranium adsorption membrane according to any one of claims 1 to 3.

5. The PAN-based electrospun uranium adsorption membrane according to claim 4, characterized in that, The PAN-based electrospun uranium adsorption membrane has nanopores on its nanofiber surface, and the nanofibers form an interwoven three-dimensional network structure, with a COF-like adsorbent uniformly loaded on the nanofiber surface.

6. The application of the PAN-based electrospun uranium adsorption membrane according to claim 4 or 5 in the field of uranium adsorption.

7. The application of the PAN-based electrospun uranium adsorption membrane according to claim 6 in the field of uranium adsorption, characterized in that, The PAN-based electrospun uranium adsorption membrane is used under the condition that the pH value is 3-6.

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