Water plant pretreatment method based on protein fiber adsorption film

Abstract

The invention discloses a water plant pretreatment method based on a protein fiber adsorption membrane, and belongs to the field of water plant technologies and wastewater pollution treatment. The invention aims to solve the problems of high cost, low efficiency and secondary pollution when the traditional water treatment method is used for treating heavy metals. The method comprises the following steps: 1, preparing protein fibers; 2, quenching and dialyzing; 3, loading protein fibrils on the filter membrane; and 4, removing heavy metals. The prepared protein fiber adsorption film can efficiently remove heavy metal ions such as mercury and lead in water, the removal rate exceeds 95%, meanwhile, green biomass materials are used, potential safety hazards do not exist, and the protein fiber adsorption film is suitable for water plants and other fields. The water plant pretreatment method based on the protein fiber adsorption film can be obtained.

Description

Technical Field

[0001] The invention belongs to the field of water plant technology and wastewater pollution control. Background Art

[0002] Due to their stability and bioaccumulation, heavy metal ions are difficult to degrade and remove naturally in water, posing a serious threat to human health and ecosystems. While traditional water treatment methods, such as precipitation and ion exchange, can remove heavy metals to a certain extent, they often suffer from high costs, low efficiency, and secondary pollution. Therefore, the development of new and efficient heavy metal removal technologies is crucial for water plant pretreatment to ensure water supply safety and environmental protection.

[0003] The surface of protein fibers contains a variety of functional groups, such as amino, carboxyl and sulfhydryl groups, which can form stable complexes with heavy metal ions, thereby achieving selective adsorption of heavy metals. In addition, the three-dimensional network structure of protein fibers provides a large number of adsorption sites, which increases the contact opportunities with heavy metal ions and improves the adsorption efficiency. These characteristics of protein fibers make them a strong candidate material for removing heavy metals in the field of water treatment. Therefore, the present invention manufactures a hybrid adsorption membrane by compounding amyloid protein onto a membrane to obtain a "water plant pretreatment method based on protein fiber adsorption membrane" that can be used for water plant pretreatment to remove heavy metals. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of high cost, low efficiency and secondary pollution in treating heavy metals by traditional water treatment methods, and to provide a water plant pretreatment method based on protein fiber adsorption membrane.

[0005] This invention provides a method for efficiently removing heavy metal ions from water using a protein fiber network, particularly for those difficult to remove using traditional water treatment technologies. This method leverages the protein fiber network's high affinity for heavy metal ions to effectively enhance their adsorption capacity. By precisely controlling the preparation and application conditions of the protein fiber, efficient capture and removal of heavy metal ions in water is achieved, thus providing a water plant pretreatment method based on a protein fiber adsorption membrane.

[0006] A water plant pretreatment method based on protein fiber adsorption membrane is specifically completed in the following steps: 1. Preparation of protein fiber: The protein monomers are dissolved in ultrapure water to obtain a protein monomer solution, which is then placed in a refrigerator for a period of time. The pH value of the solution is then adjusted to acidic, and finally heated and stirred in an oil bath for a period of time to allow the protein monomers to self-assemble into protein fibrils. 2. Quenching and dialysis: The container containing the protein fibrils is placed in an ice bath to stop the self-assembly of the protein monomers, and then dialyzed using water as a dialysis solution using a dialysis bag and stored to obtain a protein fibril dispersion; 3. Loading protein fibrils on the filter membrane: The filter membrane is rinsed and then immersed in anhydrous ethanol for a period of time to obtain a pretreated filter membrane; the protein fibril dispersion is compounded with the pretreated filter membrane to obtain a protein fiber adsorption membrane; 4. Removal of heavy metals: The protein fiber adsorption membrane is used to filter the water to be treated in the water plant at a certain rate to remove heavy metals in the water to be treated, thereby obtaining water after heavy metal removal, thereby completing a water plant pretreatment method based on the protein fiber adsorption membrane.

[0007] Principle of the present invention: 1. The present invention uses protein monomers, such as lysozyme, to form amyloid fibrils under specific conditions. These fibrils have abundant surface functional groups, such as amino, carboxyl, and sulfhydryl groups, which can form stable complexes with heavy metal ions. This interaction is one of the main mechanisms by which protein fibrils adsorb heavy metal ions. For example, amyloid fibrils formed from egg white lysozyme protein under certain physical and chemical conditions exhibit significantly increased hydrophobicity and secondary structure β-sheet content, suggesting that the exposure of hydrophobic regions during protein fibril formation may facilitate the adsorption of heavy metal ions. 2. The surface hydrophobicity of the protein fibers prepared by the present invention may change during their formation process; this increase in hydrophobicity helps enhance the protein fibers' adsorption capacity for heavy metal ions. Studies have shown that during the formation of amyloid fibers, lysozyme is accompanied by a decrease in the α-helix of the molecule, an increase in the β-sheet, and the exposure of hydrophobic regions. These changes may lead to an increase in the hydrophobicity of the fiber surface, thereby enhancing the adsorption of heavy metal ions. 3. The three-dimensional network structure formed by the protein fibers prepared by the present invention provides a large number of adsorption sites, increases the contact opportunities with heavy metal ions, and improves the adsorption efficiency; the existence of this network structure enables the protein fibers to effectively capture and remove heavy metal ions in water.

[0008] The present invention has the following effects: 1. The present invention successfully prepared protein amyloid fibers and characterized the diameter and properties of the amyloid fibers; 2. The protein fiber adsorption membrane prepared by the present invention can remove heavy metals such as mercury and lead at a rate of more than 95%; 3. The protein fiber adsorption membrane prepared by the present invention uses green biomass materials, does not pose any safety hazards, and can be used in water plants and other scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Figure 1 is an atomic force microscope image of the protein fibrils prepared in Example 1, and Figure b is a high-magnification image of Figure a; Figure 2 To measure the diameter of the protein fibrils prepared in Example 1 using NanoscopeAnalysis software, 100 fibers were randomly selected for measurement and a distribution diagram was drawn. The numbers marked in the diagram are the average diameters. Figure 3 The morphology of the protein fiber adsorption membrane prepared in step 3 of Example 1 and Example 2. (a) is Example 1, (b) is Example 2; Figure 4 These are the results of heavy metal adsorption efficiency tests using the protein fiber adsorption membrane in Examples 1 and 2. DETAILED DESCRIPTION

[0010] Specific embodiment 1: This embodiment is a water plant pretreatment method based on protein fiber adsorption membrane, which is specifically completed according to the following steps: 1. Preparation of protein fiber: The protein monomers are dissolved in ultrapure water to obtain a protein monomer solution, which is then placed in a refrigerator for a period of time. The pH value of the solution is then adjusted to acidic, and finally heated and stirred in an oil bath for a period of time to allow the protein monomers to self-assemble into protein fibrils. 2. Quenching and dialysis: The container containing the protein fibrils is placed in an ice bath to stop the self-assembly of the protein monomers, and then dialyzed using water as a dialysis solution using a dialysis bag and stored to obtain a protein fibril dispersion; 3. Loading protein fibrils on the filter membrane: The filter membrane is rinsed and then immersed in anhydrous ethanol for a period of time to obtain a pretreated filter membrane; the protein fibril dispersion is compounded with the pretreated filter membrane to obtain a protein fiber adsorption membrane; 4. Removal of heavy metals: The protein fiber adsorption membrane is used to filter the water to be treated in the water plant at a certain rate to remove heavy metals in the water to be treated, thereby obtaining water after heavy metal removal, thereby completing a water plant pretreatment method based on the protein fiber adsorption membrane.

[0011] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the protein monomer in step 1 is β-lactoglobulin, lysozyme or bovine serum albumin. The other steps are the same as those in specific embodiment 1.

[0012] Specific embodiment 3: This embodiment differs from specific embodiments 1 or 2 in that the volume ratio of the protein monomer mass to ultrapure water in step 1 is (0.01g-1.0g):(20g-30g). The other steps are the same as specific embodiments 1 or 2.

[0013] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that: the refrigerator temperature in step 1 is -30°C to 5°C; the refrigeration time in step 1 is 24 hours to 48 hours; and the pH value of the solution is adjusted to 1 to 6 using hydrochloric acid with a concentration of 2 mol / L to 5 mol / L in step 1. The other steps are the same as specific embodiments 1 to 3.

[0014] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the oil bath heating and stirring speed in step 1 is 60 rpm to 100 rpm, the oil bath temperature is 35°C to 90°C, and the heating time is 24 hours. The other steps are the same as specific embodiments 1 to 4.

[0015] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the molecular weight cut-off of the dialysis bag in step 2 is 1000-7000 and the dialysis time in step 2 is 24h-36h. The other steps are the same as specific embodiments 1 to 5.

[0016] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the mass fraction of the protein fibril dispersion in step 2 is 0.01% to 0.5%. The other steps are the same as specific embodiments 1 to 6.

[0017] Specific Embodiment 8: This embodiment differs from Specific Embodiments 1 to 7 in that the filter membrane described in step 3 is a microfiltration membrane or an ultrafiltration membrane; the filter membrane is made of polyethersulfone, polysulfone, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride, or cellulose acetate. The other steps are the same as Specific Embodiments 1 to 7.

[0018] Specific embodiment nine: The difference between this embodiment and specific embodiments one to eight is that: in step three, the protein fibril dispersion is compounded with the pretreated filter membrane by suction filtration, spin coating, spray coating or dip coating to obtain a protein fiber adsorption membrane; in step three, the filter membrane is rinsed with ultrapure water 1 to 5 times, and then the filter membrane is immersed in anhydrous ethanol for more than 24 hours to obtain a pretreated filter membrane; the volume ratio of the protein fibril dispersion in step three to the surface area of ​​the pretreated filter membrane is (10mL~40mL): (5cm 2 ~10cm 2 ). Other steps are the same as those in Specific Embodiments 1 to 8.

[0019] Specific Embodiment 10: This embodiment differs from Specific Embodiments 1 to 9 in that the heavy metal content in the water to be treated in step 4 is mercuric chloride or lead acetate solution, with a concentration of 40 ppm to 60 ppm. In step 4, the protein fiber adsorption membrane is used to filter the water to be treated at a rate of 200 mL / h to 1000 mL / h. The remaining steps are the same as Specific Embodiments 1 to 9.

[0020] The following examples are used to verify the beneficial effects of the present invention: Example 1: A water plant pretreatment method based on protein fiber adsorption membrane is specifically completed according to the following steps: 1. Preparation of protein fiber: Dissolve 0.2g of protein monomer in 20g of ultrapure water to obtain a protein monomer solution, which is then placed in a refrigerator at 4°C for 24 hours. The pH of the solution is then adjusted to 2 using 2mol / L hydrochloric acid. Finally, heat and stir in an oil bath for a period of time to allow the protein monomers to self-assemble into protein fibrils. The protein monomer described in step 1 is lysozyme; The oil bath heating and stirring speed in step 1 is 60 rpm, the oil bath temperature is 90° C., and the heating time is 10 h; 2. Quenching and dialysis: The container containing the protein fibrils was placed in an ice bath to stop the self-assembly of the protein monomers, and then dialyzed for 24 hours using a dialysis bag with water as the dialysis solution and stored to obtain a protein fibril dispersion; The molecular weight cut-off of the dialysis bag described in step 2 is 2000; The mass fraction of the protein fibril dispersion described in step 2 is 0.1%; 3. Loading protein fibrils on the filter membrane: The polyethersulfone microfiltration membrane was rinsed three times with ultrapure water, and then the membrane was immersed in anhydrous ethanol for 28 h to obtain the pretreated polyethersulfone microfiltration membrane; 10 mL of protein fibril dispersion was mixed with 5 cm 2 The pretreated polyethersulfone microfiltration membrane was composited to obtain a protein fiber adsorption membrane; In step 3, 10 mL of protein fibril dispersion was mixed with 5 cm 2 The method for compounding the pretreated polyethersulfone microfiltration membrane is as follows: 10 mL of protein fibril dispersion is poured onto the pretreated polyethersulfone microfiltration membrane for vacuum filtration to obtain a protein fiber adsorption membrane; 4. Removal of heavy metals: The protein fiber adsorption membrane is used to filter the raw water in the water plant at a certain rate to remove heavy metals in the water, thereby obtaining water free of heavy metals, thereby completing a water plant pretreatment method based on the protein fiber adsorption membrane; The heavy metal in the raw water of the water plant described in step 4 is mercuric chloride solution with a concentration of 40 ppm.

[0021] In step 4, the filtration rate of the raw water in the water plant using the protein fiber adsorption membrane is 1000 mL / h.

[0022] Example 2: This example differs from Example 1 in that the heavy metal in the raw water of the water plant described in step 4 is lead acetate solution with a concentration of 40 ppm. The other steps and parameters are the same as those in Example 1.

[0023] Example 3: The difference between this example and example 1 is that 20 mL of protein fibril dispersion was mixed with 5 cm 2 The other steps and parameters are the same as those in Example 1.

[0024] Example 4: The difference between this example and example 1 is that 30 mL of protein fibril dispersion was mixed with 5 cm 2 The other steps and parameters are the same as those in Example 1.

[0025] The protein fiber adsorption membranes prepared in Examples 3 and 4 are mainly used to explore the effects of different protein fiber network thickness and density on the properties of the prepared protein fiber adsorption membranes; Examples 1 and 2 are mainly used to explore the adsorption effects of protein fiber adsorption membranes on different heavy metals.

[0026] Figure 1 Figure 1 is an atomic force microscope image of the protein fibrils prepared in Example 1, and Figure b is a high-magnification image of Figure a; Depend on Figure 1 It can be seen that the protein fibrils prepared in Example 1 can be clearly observed and are in the form of linear fibers with a length of several microns. Different fiber networks can be prepared by controlling the heating time.

[0027] To more accurately determine the diameter of protein fibrils (amyloid fibers), the fiber diameters in the AFM images were measured using NanoscopeAnalysis software. 100 fibers were randomly selected for measurement and a distribution diagram was plotted. The numbers in the diagram indicate the average diameters. Depend on Figure 2It can be seen that the diameter of the protein fibrils is distributed around 8-10 nm, indicating that there are amyloid fibers of various sizes when the heating time is short. As the heating time increases, the size of the protein fibers increases and gradually becomes more uniform.

[0028] The protein fiber adsorption film prepared in the example was characterized by AFM, and the images at different magnifications were as follows: Figure 3 As shown; Figure 3 The morphology of the protein fiber adsorption membrane prepared in step 3 of Example 1 and Example 2. (a) is Example 1, (b) is Example 2; Depend on Figure 3 It can be seen that multiple layers of protein fibers are loaded on the surface of the microfiltration membrane, forming a protein fiber network with different thicknesses and densities.

[0029] Figure 4 The results of heavy metal adsorption efficiency tests using protein fiber adsorption membranes in Examples 1 and 2 are as follows; from Figure 4 It can be seen that the removal rates of mercury ions and lead ions by the protein fiber adsorption membrane are 95.3% and 97.2% respectively, both above 95%, which proves the ability of the adsorption membrane to remove heavy metals.

Claims

1. A water plant pretreatment method based on protein fiber adsorption membrane, characterized in that The method is specifically completed in the following steps:

1. Preparation of protein fiber: The protein monomers are dissolved in ultrapure water to obtain a protein monomer solution, which is then placed in a refrigerator for a period of time. The pH value of the solution is then adjusted to acidic, and finally heated and stirred in an oil bath for a period of time to allow the protein monomers to self-assemble into protein fibrils.

2. Quenching and dialysis: The container containing the protein fibrils is placed in an ice bath to stop the self-assembly of the protein monomers, and then dialyzed using water as a dialysis solution using a dialysis bag and stored to obtain a protein fibril dispersion; 3. Loading protein fibrils on the filter membrane: The filter membrane is rinsed and then immersed in anhydrous ethanol for a period of time to obtain a pretreated filter membrane; the protein fibril dispersion is compounded with the pretreated filter membrane to obtain a protein fiber adsorption membrane; 4. Removal of heavy metals: The protein fiber adsorption membrane is used to filter the water to be treated in the water plant at a certain rate to remove heavy metals in the water to be treated, thereby obtaining water after heavy metal removal, thereby completing a water plant pretreatment method based on the protein fiber adsorption membrane.

2. A water plant pretreatment method based on protein fiber adsorption membrane according to claim 1, characterized in that The protein monomer in step 1 is β-lactoglobulin, lysozyme or bovine serum albumin.

3. A water plant pretreatment method based on protein fiber adsorption membrane according to claim 1, characterized in that The volume ratio of the protein monomer described in step 1 to ultrapure water is (0.01g~1.0g):(20g~30g).

4. A water plant pretreatment method based on protein fiber adsorption membrane according to claim 1, characterized in that The temperature of the refrigerator in step 1 is -30°C to 5°C; the refrigeration time in step 1 is 24h to 48h; and in step 1, the pH value of the solution is adjusted to 1 to 6 using hydrochloric acid with a concentration of 2mol / L to 5mol / L.

5. A water plant pretreatment method based on protein fiber adsorption membrane according to claim 1, characterized in that The oil bath heating and stirring speed in step 1 is 60 rpm~100 rpm, the oil bath temperature is 35°C~90°C, and the heating time is 24 hours.

6. A water plant pretreatment method based on protein fiber adsorption membrane according to claim 1, characterized in that The molecular weight cut-off of the dialysis bag in step 2 is 1000-7000; the dialysis time in step 2 is 24h-36h.

7. A water plant pretreatment method based on protein fiber adsorption membrane according to claim 1, characterized in that The mass fraction of the protein fibril dispersion described in step 2 is 0.01% to 0.5%.

8. A water plant pretreatment method based on protein fiber adsorption membrane according to claim 1, characterized in that The filter membrane described in step 3 is a microfiltration membrane or an ultrafiltration membrane; the material of the filter membrane is polyethersulfone, polysulfone, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride or cellulose acetate.

9. A water plant pretreatment method based on protein fiber adsorption membrane according to claim 1, characterized in that In step 3, the protein fibril dispersion is composited with the pretreated filter membrane by suction filtration, spin coating, spraying or dipping to obtain a protein fiber adsorption membrane; in step 3, the filter membrane is rinsed with ultrapure water 1 to 5 times, and then the filter membrane is immersed in anhydrous ethanol for more than 24 hours to obtain a pretreated filter membrane; the volume ratio of the protein fibril dispersion in step 3 to the surface area of ​​the pretreated filter membrane is (10 mL to 40 mL): (5 cm 2 ~10cm 2 ).

10. A water plant pretreatment method based on protein fiber adsorption membrane according to claim 1, characterized in that The heavy metal in the water to be treated in the water plant described in step 4 is mercuric chloride or lead acetate solution, with a concentration of 40ppm to 60ppm. In step 4, the filtration rate of the water to be treated in the water plant using the protein fiber adsorption membrane is 200mL / h to 1000mL / h.

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