Fiber hybrid membrane for synchronously removing radioactive cesium and strontium and preparation method and application thereof

Abstract

The application belongs to the technical field of composite materials, and particularly discloses a fiber hybrid membrane for synchronously removing radioactive cesium and strontium as well as a preparation method and application thereof. The preparation method comprises the following steps: adjusting the pH of a beta-lactoglobulin solution, centrifuging, collecting the supernatant, filtering, dialyzing, freeze-drying, and obtaining beta-lactoglobulin monomers; dissolving the beta-lactoglobulin monomers in ultrapure water, adjusting the pH, and water-bath heating to obtain an amyloid fiber solution; adding potassium titanate to the amyloid fiber solution, adjusting the pH, and obtaining amyloid fiber loaded with titanium dioxide; and mixing the amyloid fiber loaded with titanium dioxide with activated carbon to obtain an amyloid fiber hybrid membrane. The fiber hybrid membrane for synchronously removing radioactive cesium and strontium and the preparation method and application thereof have high membrane flux, excellent adsorption selectivity and cycle performance, can accurately adsorb radioactive cesium and strontium in a complex seawater system, and do not produce secondary waste in the treatment process, and are low in price.

Description

Technical Field

[0001] This invention relates to the field of composite materials technology, and in particular to fiber hybrid membranes for simultaneous removal of radioactive cesium and strontium, their preparation methods, and applications. Background Technology

[0002] Nuclear energy, as a clean energy source, has received attention from many countries for its development.

[0003] Among numerous radionuclides, strontium-90 (90Sr) and cesium-137 are priority targets for treatment due to their long half-lives (28.79 years and 30.17 years, respectively), high radioactivity, and their existence in ionic form, making them highly mobile and biotoxic. Since 2011, excessive levels of 137Cs and 90Sr have still been detected in marine organisms. These substances can easily transfer to the human body through the food chain, causing cell damage and death. Furthermore, 90Sr tends to accumulate in bone tissue, leading to diseases such as leukemia.

[0004] Therefore, the removal of 137Cs and 90Sr is of great significance: on the one hand, it can benefit seawater protection, preventing radioactive nuclides from damaging the environment and irradiating marine life; on the other hand, it allows for the recovery of 137Cs and 90Sr, both of which have significant potential applications in medical, industrial, and other sectors. However, radioactive waste is acidic and has a complex composition, thus requiring a selective removal of Cs from the complex aquatic environment. + 、Sr 2+ Ions remain a challenging area of ​​research. Summary of the Invention

[0005] The purpose of this invention is to provide a fiber hybrid membrane for the simultaneous removal of radioactive cesium and strontium, its preparation method, and its application. This hybrid membrane has high membrane flux, excellent adsorption selectivity, and recycling performance. It can accurately adsorb radioactive cesium and strontium in extremely complex seawater systems, and does not generate secondary waste during the treatment process. It is inexpensive and has a broad market.

[0006] To achieve the above objectives, the present invention provides a method for preparing a fiber hybridization membrane for simultaneous removal of radioactive cesium and strontium, comprising the following steps:

[0007] S1. Adjust the pH of the β-lactoglobulin solution, centrifuge, collect the supernatant, filter, dialyze, freeze dry, and obtain β-lactoglobulin monomer;

[0008] S2. Dissolve the β-lactoglobulin monomer obtained in step S1 in ultrapure water, stir until homogeneous, adjust the pH, and heat in a water bath to obtain an amyloid cellulose solution.

[0009] S3. Add potassium titanate to the amyloid fiber solution obtained in step S2, adjust the pH, and shake at a constant temperature to obtain amyloid fiber loaded with titanium dioxide.

[0010] S4. Mix the amyloid fibers loaded with titanium dioxide obtained in step S3 with activated carbon, stir evenly, and vacuum filter to obtain an amyloid fiber hybrid membrane.

[0011] Preferably, in step S1, the pH of β-lactoglobulin with a mass concentration of 10 wt% is adjusted to 4.5 using hydrochloric acid with a mass fraction of 1%-5%.

[0012] Preferably, in step S1, the centrifugation is performed three times at a speed of 8000 rpm, each time for 15 minutes and with a 12-hour interval between each centrifugation.

[0013] Preferably, in step S1, a 0.45μm filter is used for filtration, and dialysis is performed for 5-7 days using an 8000Da dialysis bag. The dialysis solution is ultrapure water, and the solution is freeze-dried at -60°C for 48 hours to obtain β-lactoglobulin monomer, which is then stored at 4°C.

[0014] Preferably, in step S2, 5% hydrochloric acid is added to adjust the pH to 2, the water bath heating temperature is 90°C, and the heating time is 5 hours.

[0015] Preferably, in step S3, 1M NaOH is added to adjust the pH to 2.5, and the mixture is placed in a water bath shaker and shaken at 160 rpm and 25°C for 14 hours.

[0016] Preferably, in step S4, the mass ratio of amyloid fiber-loaded titanium dioxide to activated carbon is 3:7.

[0017] The present invention also provides a fiber hybrid membrane for simultaneous removal of radioactive cesium and strontium, which is prepared by a method for preparing a fiber hybrid membrane for simultaneous removal of radioactive cesium and strontium.

[0018] The present invention also provides the application of a fiber hybrid membrane for the simultaneous removal of radioactive cesium and strontium, which is used to remove radioactive cesium and strontium from seawater.

[0019] The advantages and beneficial effects of the fiber hybrid membrane for simultaneous removal of radioactive cesium and strontium, its preparation method, and its application in this invention are as follows:

[0020] 1. The hybrid membrane of this invention uses β-lactoglobulin as the core and activated carbon and other macromolecules as carriers to construct a green and environmentally friendly composite adsorption system. The raw materials are widely available and no toxic or polluting reagents are added during the preparation process. Through the synergistic effect of the hierarchical channels of amyloid fibers and the high porosity of activated carbon, high membrane flux is achieved, which can rapidly treat large volumes of radioactive cesium and strontium in seawater and significantly improve the treatment efficiency per unit time. By regulating the coordination chemistry between amino and carboxyl groups on the surface of amyloid fibers and nano-sized titanium dioxide, the material is endowed with excellent adsorption selectivity. Furthermore, the hybrid membrane has excellent cycling performance and adsorption capacity.

[0021] 2. The preparation process does not require high temperature and high pressure conditions, is simple to operate and has low equipment requirements, thus reducing production costs. During the process, iodine ions are fixed through physical adsorption and coordination reaction, without generating any secondary waste. The membrane material after adsorption saturation can achieve long-term stable storage of radionuclides through a safe curing process, fundamentally avoiding the leakage risk of storage decay method, and has broad prospects for industrial application.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the synthesis of amyloid fiber hybrid membrane according to the present invention;

[0024] Figure 2 The morphology of the activated carbon amyloid fiber-supported titanium dioxide hybrid membrane provided in Example 1 of the present invention under a scanning electron microscope;

[0025] Figure 3 This invention provides a comparison of the removal effects of different materials on cesium and strontium in Embodiment 1 of the present invention;

[0026] Figure 4 Example 1 of the present invention provides a comparison of the removal effects of activated carbon amyloid fiber-supported titanium dioxide hybrid membrane on cesium and strontium in different water bodies, where A is ultrapure water, B is tap water, C is seawater, and D is lake water. Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0029] In this invention, unless otherwise specified, all other test materials and instruments are conventional test materials in the field and can be purchased through commercial channels.

[0030] Example 1

[0031] A method for preparing a fiber hybridization membrane for simultaneous removal of radioactive cesium and strontium, such as... Figure 1 As shown, it includes the following steps:

[0032] S1 was prepared by adjusting the pH of 10wt% β-lactoglobulin to 4.5 with 1% hydrochloric acid. It was centrifuged three times at 8000 rpm for 15 min each time with a 12 h interval between centrifugations. The supernatant was collected, filtered through a 0.45 μm filter, dialyzed for 7 days with an 8000 Da dialysis bag and ultrapure water as the dialysate. The β-lactoglobulin monomer was then freeze-dried at -60℃ for 48 h and stored at 4℃.

[0033] S2. Dissolve 1g of β-lactoglobulin monomer obtained in step S1 in 49mL of ultrapure water, stir well, add 5% hydrochloric acid to adjust the pH to 2, heat in a 90℃ water bath for 5h to obtain a 2wt% amyloid cellulose solution.

[0034] S3. Add 3.046 g of potassium titanate to the amyloid fiber solution with a mass concentration of 2 wt% obtained in step S2, add 1 M NaOH to adjust the pH to 2.5, place it in a water bath shaker, and shake at 160 rpm and 25°C for 14 h to obtain amyloid fiber loaded with titanium dioxide.

[0035] S4. Mix 0.03g of amyloid fiber-loaded titanium dioxide obtained in step S3 with 0.07g of activated carbon, stir evenly, and vacuum filter for 8min, wherein the vacuum degree is 0.01MPa, to obtain 100mg of amyloid fiber hybrid membrane AC-βFs-TiO2.

[0036] The morphology of the activated carbon amyloid fiber-supported titanium dioxide hybrid membrane provided in Example 1 is as follows: Figure 2 .

[0037] Comparative Example 1

[0038] Commercial activated carbon (AC) was purchased from Zhengzhou Zhongliao Co., Ltd.

[0039] Comparative Example 2

[0040] The method for preparing a hybridization membrane to remove radioactive cesium and strontium includes the following steps:

[0041] S1 was prepared by adjusting the pH of 10wt% β-lactoglobulin to 4.5 with 1% hydrochloric acid. It was centrifuged three times at 8000 rpm for 15 min each time with a 12 h interval between centrifugations. The supernatant was collected, filtered through a 0.45 μm filter, dialyzed for 7 days with an 8000 Da dialysis bag and ultrapure water as the dialysate. The β-lactoglobulin monomer was then freeze-dried at -60℃ for 48 h and stored at 4℃.

[0042] S2. Dissolve 1g of β-lactoglobulin monomer obtained in step S1 in 49mL of ultrapure water, stir well, add 5% hydrochloric acid to adjust the pH to 2, heat in a 90℃ water bath for 5h to obtain a 2wt% amyloid cellulose solution.

[0043] S3. Mix the 2wt% amyloid cellulose solution obtained in step S2 with 0.07g of activated carbon, stir evenly, and vacuum filter for 8min, wherein the vacuum degree is 0.01MPa, to obtain 100mg of amyloid cellulose hybrid membrane (AC-βFs).

[0044] The removal rates of cesium and strontium by the three hybrid membranes in Comparative Example 1, Comparative Example 2, and Example 1 were compared. The experimental procedure was as follows: 10 mL of a solution containing cesium and strontium was simultaneously filtered by the three hybrid membranes of Comparative Example 1, Comparative Example 2, and Example 1. The residual cesium and strontium concentrations before and after filtration were compared. The cesium ion concentration was 50 mg / L, the strontium ion concentration was 50 mg / L, 10 mL of solution was filtered, and vacuum filtration was performed for 8 min at a vacuum degree of 0.01 MPa. The hybrid membranes exhibited excellent ability to simultaneously remove cesium and strontium, and also demonstrated excellent membrane flux. The results are as follows: Figure 3 As shown.

[0045] Depend on Figure 3 It can be seen that in solutions with high concentrations of cesium and strontium coexisting, the amyloid cellulose hybrid membrane AC-βFs-TiO2 membrane still has extremely high removal performance of cesium and strontium ions, close to 100%, while commercial activated carbon has almost no removal performance.

[0046] The cyclic removal performance of the amyloid fiber hybrid membrane provided in Example 1 was determined in different systems.

[0047] The experimental procedure is as follows: Strontium and cesium solutions of 5 mg / L were prepared using ultrapure water, tap water, lake water, and seawater, respectively. 10 mL of solution was filtered each time, and the filtration was repeated 5 times. Vacuum filtration time was 8 min. The results are as follows: Figure 4 As shown.

[0048] Depend on Figure 4 It can be seen that the hybrid membrane exhibits excellent circulation performance in ultrapure water and tap water, and its reusability is almost unaffected. However, in seawater and lake water, a large number of competing ions such as potassium ions and sodium ions have a significant impact on the removal of strontium ions, but have a smaller impact on cesium ions. It is believed that the membrane can remove cesium and strontium ions from seawater simultaneously and has a very strong treatment capacity.

[0049] Therefore, the present invention employs the above-mentioned fiber hybrid membrane for simultaneous removal of radioactive cesium and strontium, its preparation method, and its application. This hybrid membrane has high membrane flux, excellent adsorption selectivity, and recycling performance. It can accurately adsorb radioactive cesium and strontium in extremely complex seawater systems, and does not generate secondary waste during the treatment process. It is inexpensive and has a broad market.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a fiber hybridization membrane for simultaneous removal of radioactive cesium and strontium, characterized in that: Includes the following steps: S1. Adjust the pH of the β-lactoglobulin solution, centrifuge, collect the supernatant, filter, dialyze, freeze dry, and obtain β-lactoglobulin monomer; In step S1, the pH of 10wt% β-lactoglobulin is adjusted to 4.5 using hydrochloric acid with a mass fraction of 1%-5%. S2. Dissolve the β-lactoglobulin monomer obtained in step S1 in ultrapure water, stir until homogeneous, adjust the pH, and heat in a water bath to obtain an amyloid cellulose solution. In step S2, 5% hydrochloric acid is added to adjust the pH to 2, the water bath heating temperature is 90°C, and the heating time is 5 hours. S3. Add potassium titanate to the amyloid fiber solution obtained in step S2, adjust the pH, and shake at a constant temperature to obtain amyloid fiber loaded with titanium dioxide. In step S3, add 1M NaOH to adjust the pH to 2.5, place in a water bath shaker, and shake at 160 rpm and 25°C for 14 hours. S4. Mix the amyloid fibers loaded with titanium dioxide obtained in step S3 with activated carbon, stir evenly, and vacuum filter to obtain an amyloid fiber hybrid membrane. In step S4, the mass ratio of amyloid fiber loaded with titanium dioxide to activated carbon is 3:

7.

2. The method for preparing a fiber hybrid membrane for simultaneous removal of radioactive cesium and strontium according to claim 1, characterized in that: In step S1, the centrifugation is performed three times at a speed of 8000 rpm, each time for 15 minutes and with a 12-hour interval between each centrifugation.

3. The method for preparing a fiber hybrid membrane for simultaneous removal of radioactive cesium and strontium according to claim 1, characterized in that: In step S1, the mixture was filtered using a 0.45 μm filter, dialyzed for 5-7 days using an 8000 Da dialysis bag, and the dialysate was ultrapure water. The mixture was then freeze-dried at -60°C for 48 hours to obtain β-lactoglobulin monomer, which was then stored at 4°C.

4. A fiber hybrid membrane for simultaneously removing radioactive cesium and strontium, characterized in that: It is prepared by the preparation method described in any one of claims 1-3.

5. The application of the fiber hybrid membrane for simultaneous removal of radioactive cesium and strontium as described in claim 4, characterized in that: It is used to remove radioactive cesium and strontium from seawater.

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