Amyloid fiber hybrid membrane as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of composite material preparation, and particularly discloses an amyloid fiber hybrid membrane as well as a preparation method and application thereof. The preparation method comprises the following steps: adjusting the pH value of a beta-lactoglobulin solution with the mass concentration of 10wt%, centrifuging, collecting supernate, filtering, dialyzing and freeze-drying to obtain a beta-lactoglobulin monomer; the method comprises the following steps: dissolving a beta-lactoglobulin monomer in ultrapure water, uniformly stirring, adjusting the pH value, and heating in a water bath to obtain an amyloid fiber solution; adding bismuth nitrate into the amyloid fiber solution, adjusting the pH value, and oscillating at a constant temperature to obtain amyloid fiber loaded bismuth hydroxide; and mixing the amyloid fiber loaded bismuth hydroxide with activated carbon, uniformly stirring, and carrying out vacuum filtration to obtain the amyloid fiber hybrid membrane. The invention discloses an amyloid fiber hybrid membrane as well as a preparation method and application thereof. The hybrid membrane has relatively high membrane flux, excellent adsorption selectivity and cycle performance, and can remove iodide ions from relatively complex radioactive medical waste liquid.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite material preparation, and particularly relates to an amyloid fiber hybrid membrane, a preparation method thereof, and an application thereof. Background Art

[0002] Radioactive iodine isotopes have irreplaceable application values in the field of nuclear medicine. I 131 As the core drug for treating hyperthyroidism and thyroid cancer, it realizes disease control by targeting and destroying thyroid cells; I 123 And I 124 is a key tracer for single photon emission computed tomography imaging, and is used for thyroid function evaluation and tumor localization; I 125 then precisely treats solid tumors such as prostate cancer through brachytherapy. However, the four isotopes have long half-lives and strong radioactive toxicity. Once leaked from medical waste liquid, they can rapidly migrate and diffuse through water bodies, accumulate in the human thyroid tissue for a long time after being enriched through the food chain, and induce cell carcinogenesis and genetic damage. Clinical data shows that after hyperthyroidism patients receive a radiotherapy dose of 100 - 1000 MBq, about 70% of the radioactive iodine will be excreted with urine, etc., forming radioactive waste liquid with a high iodine concentration and complex components.

[0003] So far, for the removal of iodide ions, there are adsorption methods, chemical precipitation methods, ion exchange methods, etc. Among them, the adsorption method has received attention in the removal of iodide ions due to its advantages such as simple operation and less secondary pollution. With the in-depth research, a variety of adsorbents have been developed, such as carbon materials, nanomaterials, metal oxides, etc. In recent years, metal oxides such as Ag, Bi, and Cu have received extensive attention due to their excellent removal ability for iodides. These metals are easy to combine with iodide ions to form precipitates, thereby achieving the removal purpose. However, there are still some problems, such as the high price, toxicity, and scarcity of silver. Therefore, bismuth-based compounds such as Bi2O3 have become one of the most promising candidates for removing iodide ions. It has weak toxicity, stable properties, and is cheap and easily available. The iodine oxide formed by reacting with iodide ions has good thermodynamic stability. Nevertheless, at present, no bismuth-based adsorbent that can accurately capture iodide ions in a short time under the conditions of a large volume and coexistence of multiple ions has been developed. Summary of the Invention

[0004] The present invention aims to provide an amyloid fiber hybrid membrane, a preparation method thereof, and an application thereof. The hybrid membrane has a high membrane flux, excellent adsorption selectivity and recycling performance, can remove iodide ions from relatively complex radioactive medical waste liquid, does not produce secondary waste during the treatment process, and has an extremely broad market prospect.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A preparation method of an amyloid fiber hybrid membrane, comprising the following steps:

[0007] S1. Adjust the pH of a β-lactoglobulin solution with a mass concentration of 10 wt%, centrifuge, collect the supernatant, filter, dialyze, and freeze-dry to obtain β-lactoglobulin monomers;

[0008] S2. Dissolve the β-lactoglobulin monomers obtained in S1 in ultrapure water, stir evenly, adjust the pH, and heat in a water bath to obtain an amyloid fiber solution with a mass concentration of 2 wt%;

[0009] S3. Add bismuth nitrate to the amyloid fiber solution with a mass concentration of 2 wt% obtained in S2, adjust the pH, and oscillate at a constant temperature to obtain amyloid fibers loaded with bismuth hydroxide;

[0010] S4. Mix the amyloid fibers loaded with bismuth hydroxide obtained in S3 with activated carbon, stir evenly, and perform vacuum filtration to obtain an amyloid fiber hybrid membrane.

[0011] Preferably, in S1, hydrochloric acid with a mass fraction of 1% - 5% is used to adjust the pH of the β-lactoglobulin with a mass concentration of 10 wt% to 4.6.

[0012] Preferably, in S1, centrifugation is performed three times at a rotation speed of 8000 rpm, each time for 15 min, and the interval between each centrifugation is 12 h.

[0013] Preferably, in S1, filtration is performed using a 0.45 μm filter, dialysis is performed using an 8000 Da dialysis bag for 5 - 7 days, the dialysis solution is ultrapure water, freeze-drying is performed at -50°C to -60°C for 48 h to obtain β-lactoglobulin monomers, and they are stored in an environment at 4°C.

[0014] Preferably, in S2, hydrochloric acid with a mass fraction of 5% is added to adjust the pH to 2, the water bath heating temperature is 90°C, and the heating time is 5 h.

[0015] Preferably, in S3, sodium hydroxide with a mass fraction of 1% is added to adjust the pH to 4.25, it is placed in a water bath shaker, and oscillated at a constant temperature of 25°C at a rotation speed of 160 rpm for 12 h.

[0016] Preferably, in S4, the mass ratio of the amyloid fibers loaded with bismuth hydroxide to activated carbon is 1:9.

[0017] The present invention also provides an amyloid fiber hybrid membrane prepared by the described preparation method.

[0018] The present invention also provides the application of the amyloid fiber hybrid membrane described above or the amyloid fiber hybrid membrane prepared by the described preparation method in removing iodide ions in radioactive medical waste liquid.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects:

[0020] (1) The present invention discloses an amyloid fiber hybrid membrane, a preparation method and an application thereof. The hybrid membrane uses β-lactoglobulin and activated carbon as core raw materials to construct a green and environmentally friendly composite adsorption system. The raw materials are widely sourced and no toxic reagents are added during the preparation process. Through the synergistic effect of the multi-level pores of the amyloid fiber and the high-porosity structure of the activated carbon, high membrane flux is achieved, and large-volume radioactive waste liquid can be rapidly treated, significantly improving the treatment efficiency per unit time. By regulating the coordination chemistry between the amino and carboxyl groups on the surface of the amyloid fiber and nano-bismuth hydroxide, the material is endowed with excellent adsorption selectivity, and the hybrid membrane has excellent recycling performance and adsorption capacity.

[0021] (2) The preparation process does not require high-temperature and high-pressure conditions, is easy to operate and has low equipment requirements, reducing production costs. During the treatment process, iodide ions are fixed through physical adsorption and coordination reactions, and no secondary waste is generated. The membrane material after adsorption saturation can achieve long-term stable sealing of radionuclides through a safe solidification process, fundamentally avoiding the leakage risk of the storage decay method, and having broad industrial application prospects.

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

[0023] Figure 1 is the process flow chart for synthesizing the amyloid fiber hybrid membrane of the present invention;

[0024] Figure 2 is the infrared spectrum of the functional groups of the amyloid fiber hybrid membrane provided in Example 1;

[0025] Figure 3 is the comparison result of the distribution coefficient (Kd) between Example 1 and the comparative example;

[0026] Figure 4 is the recycling performance result of the amyloid fiber hybrid membrane provided in Example 1 in an iodide ion solution. Detailed Embodiments

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

[0028] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention belongs.

[0029] Source of test materials:

[0030] In the present invention, unless otherwise specified, other test materials and instrument equipment are all conventional test materials in the art and can be obtained through commercial channels.

[0031] The process flow chart for synthesizing the amyloid fiber hybrid membrane in the examples is as Figure 1 shown.

[0032] Example 1

[0033] A method for preparing an amyloid fiber hybrid membrane includes the following steps:

[0034] S1. Use hydrochloric acid with a mass fraction of 1% to adjust the pH of β-lactoglobulin with a mass concentration of 10 wt% to 4.6, centrifuge three times at a rotation speed of 8000 rpm for 15 minutes each time, with a 12-hour interval between each centrifugation. Collect the supernatant, filter it using a 0.45 μm filter, dialyze it for 7 days using an 8000 Da dialysis bag, with the dialysis solution being ultrapure water, and freeze-dry it at -60 °C for 48 hours to obtain β-lactoglobulin monomers, and store them in an environment at 4 °C;

[0035] S2. Dissolve 2 g of the β-lactoglobulin monomers obtained in S1 in 98 mL of ultrapure water, stir evenly, add hydrochloric acid with a mass fraction of 5% to adjust the pH to 2, and heat it in a water bath at 90 °C for 5 hours to obtain an amyloid fiber solution with a mass concentration of 2 wt%;

[0036] S3. Add 3.153 g of bismuth nitrate to the amyloid fiber solution with a mass concentration of 2 wt% obtained in S2, add NaOH with a mass fraction of 1% to adjust the pH to 4.25, place it in a water bath shaker, and shake it at a constant temperature of 25 °C at a rotation speed of 160 rpm for 12 hours to obtain amyloid fibers loaded with bismuth hydroxide;

[0037] S4. Mix 0.01 g of the amyloid fibers loaded with bismuth hydroxide obtained in S3 with 0.09 g of activated carbon, stir evenly, and perform vacuum filtration for 3 minutes, where the vacuum degree is 0.01 MPa, to obtain 100 mg of the amyloid fiber hybrid membrane AC-βFs-Bi(OH)3.

[0038] Comparative Example 1

[0039] It is commercial activated carbon purchased from Zhengzhou Zhongliao Environmental Protection Co., Ltd.

[0040] The following tests are used to verify the effectiveness of the amyloid fiber hybrid membrane provided in the above Example 1.

[0041] 1. Perform infrared characterization on the functional groups of the amyloid fiber hybrid membrane provided in the above Example 1, and the results are as Figure 2 .

[0042] From Figure 2It can be seen that the Bi-O bonds are successfully loaded on the fibers, and the presence of Bi-O bonds can be clearly observed on the membrane before adsorbing iodide ions; after filtration, the Bi-O bonds coincide with the Bi-I bonds.

[0043] 2. Compare the distribution coefficient (Kd) of the amyloid fiber hybrid membrane provided in Example 1 and the commercial activated carbon provided in Comparative Example 1. The test process is as follows: Filter and remove iodide ions from the amyloid fiber hybrid membrane prepared in Example 1 and the commercial activated carbon provided in Comparative Example 1 under the conditions of different concentrations of SO4 2- ions (0 - 500 mg / L), where the iodide ion concentration is 100 mg / L, the filtration solution is 10 mL, vacuum filtration is carried out for 3 min, and the vacuum degree is 0.01 MPa. The hybrid membrane shows excellent selectivity performance, and the results are as Figure 3 shown.

[0044] It can be Figure 3 seen that in the face of the presence of high-concentration sulfate ions, the amyloid fiber hybrid membrane AC-βFs-Bi(OH)3 membrane can still have extremely high selectivity for iodide ions, and the Kd index is 10 6 times higher than that of commercial activated carbon.

[0045] 3. Measure the cycling performance of the amyloid fiber hybrid membrane provided in Example 1 in an iodide ion solution, and evaluate the volume of radioactive wastewater that can be treated per square meter of the hybrid membrane.

[0046] The test scheme is as follows: Prepare 1000 mL of a 4.2 mg / L solution, and cycle the carbon-based hybrid membrane prepared in Example 1 100 times to filter and remove iodide ions. Each time the filtration solution is 10 mL, and the vacuum filtration time is 3 min. The results are as Figure 4 shown.

[0047] It can be Figure 4 seen that the hybrid membrane shows excellent cycling performance and extremely strong treatment ability.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing an amyloid fiber hybrid membrane, characterized in that: The following steps are involved: S1, adjusting the pH of the β-lactoglobulin solution with a mass concentration of 10wt%, centrifuging, collecting the supernatant, filtering, dialyzing, and freeze-drying to obtain β-lactoglobulin monomer; S2, dissolving the β-lactoglobulin monomer obtained in S1 in ultrapure water, stirring evenly, adjusting the pH, and heating in a water bath to obtain an amyloid fiber solution with a mass concentration of 2 wt%; S3, adding bismuth nitrate to the amyloid fiber solution with a mass concentration of 2 wt% obtained in S2, adjusting the pH, and shaking at a constant temperature to obtain amyloid fibers loaded with bismuth hydroxide; S4. Mix the amyloid fiber loaded with bismuth hydroxide obtained in S3 with activated carbon, stir evenly, and perform vacuum filtration to obtain an amyloid fiber hybrid membrane.

2. The preparation method according to claim 1, characterized in that: In S1, the pH of β-lactoglobulin having a mass concentration of 10 wt % is adjusted to 4.6 using hydrochloric acid having a mass fraction of 1% to 5%.

3. The preparation method according to claim 1, characterized in that: In S1, the centrifugation was performed at 8000 rpm for three times, each time for 15 min and each time for 12 h.

4. The preparation method according to claim 1, characterized in that: In S1, a 0.45 μm filter was used for filtration and dialyzed with an 8000 Da dialysis bag for 5 to 7 days. The dialysate was ultrapure water and freeze-dried at -50°C to -60°C for 48 hours to obtain β-lactoglobulin monomer, which was stored at 4°C.

5. The preparation method according to claim 1, characterized in that: In S2, hydrochloric acid with a mass fraction of 5% is added to adjust the pH to 2, the water bath heating temperature is 90° C., and the heating time is 5 hours.

6. The preparation method according to claim 1, characterized in that: In S3, 1% NaOH was added to adjust the pH to 4.25, and the mixture was placed in a water bath shaker and shaken at a constant temperature of 25° C. at a rotation speed of 160 rpm for 12 h.

7. The preparation method according to claim 1, characterized in that: In S4, the mass ratio of the amyloid fiber-loaded bismuth hydroxide to the activated carbon is 1:

9.

8. The amyloid fiber hybrid membrane prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the amyloid fiber hybrid membrane according to claim 8 or the amyloid fiber hybrid membrane prepared by the preparation method according to any one of claims 1 to 7 in removing iodine ions from radioactive medical waste liquid.

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