Fe-ni / poly sulfone hollow fiber hybrid membrane and preparation method thereof

Abstract

The application refers to Fe-Ni / polysulfone inorganic-organic hollow fiber hybrid membrane and a preparation method thereof, including a preparation process: step 1: dissolving polysulfone in an organic solvent and adding an additive, stirring to form a uniform solution; then adding 0.5% to 30% of Fe and Ni metal powder by mass ratio under stirring to obtain a spinning solution; step 2: mixing pure water and a polar solvent according to a certain ratio to form a uniform solution, obtaining an inner coagulation bath; step 3: transferring the spinning solution to a liquid supply tank after vacuum degassing, quantitatively and constantly conveying to a spinneret, at the same time, quantitatively and constantly conveying the inner coagulation bath into the spinneret, the spinning solution passing through an air gap and entering an outer coagulation bath, the hollow fiber membrane being coagulated and formed under the action of the inner / outer coagulation bath, being washed by pure water and dried to obtain the Fe-Ni / polysulfone hollow fiber membrane, which has a typical asymmetric structure, high mechanical strength and good biocompatibility, can significantly improve the hydrophilicity of the membrane and can also enhance the protein contamination resistance of the membrane.

Description

Technical Field

[0001] This invention belongs to the field of membrane separation technology, and specifically refers to an Fe-Ni / polysulfone hollow fiber hybrid membrane and its preparation method. Background Technology

[0002] Hemodialysis uses a dialyzer to replace some of the glomerular function in the patient's kidneys to achieve filtration and reabsorption, and a highly selective separation membrane is the main component of the dialyzer. Since bisphenol polysulfone (PSf) polymers were used to prepare hemodialysis membranes, polymeric materials represented by polysulfone have been favored by the market due to their good film-forming properties, high temperature resistance, corrosion resistance, and high mechanical strength. However, because polysulfone itself lacks hydrophilic groups such as hydroxyl groups, polysulfone membranes exhibit overall hydrophobic characteristics. Consequently, during the separation process, their ultrafiltration coefficient is relatively low. At the same time, medium and large molecular weight proteins are easily adsorbed into the membrane pores, causing membrane fouling, which significantly reduces the ultrafiltration coefficient, clearance rate, and service life.

[0003] To address the hydrophilicity, biocompatibility, and antifouling properties of hemodialysis membranes, modification methods such as blending and grafting have been employed. Polysulfone composite membranes prepared by blending exhibit weak bonding between the modified membrane layer and the polysulfone, leading to easy detachment and impacting operational stability and lifespan. Grafting modification involves chemically bonding organic compounds containing desired active functional groups to the membrane layer via a grafting reaction. This method offers strong bonding and high stability, but its complex preparation process increases operating costs. Metal particle doping is a simple and effective modification method; however, there are currently no reports on the preparation of hollow fiber hybrid membranes using Fe-Ni metal powder blended with polysulfone polymers. The preparation of Fe-Ni / polysulfone hollow fiber membranes represents a new attempt in this field. Summary of the Invention

[0004] In one aspect, the present invention provides an Fe-Ni / polysulfone hollow fiber hybrid membrane, which has a typical asymmetric structure, high mechanical strength, good biocompatibility, and through the synergistic effect of Fe and Ni, can significantly improve the hydrophilicity of the fiber membrane and enhance its resistance to protein fouling, thus showing good application prospects.

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

[0006] A Fe-Ni / polysulfone hollow fiber hybrid membrane,

[0007] Fe-Ni / polysulfone hollow fiber hybrid membranes with different molecular weight cutoffs are obtained by spinning the casting solution into filaments through a spinning device and then undergoing post-treatment.

[0008] The prepared casting solution consists of the following components, each by mass percentage: 12%–35% polysulfone, 0.5%–30% additives, 0.5%–30% Fe and Ni metal powders, and 40%–90% organic solvents.

[0009] In some technical solutions, the additive is a hydrophilic polymer; and / or,

[0010] The organic solvent is a polar solvent.

[0011] In some technical solutions, the additive is selected from polyethylene glycol (PEG) or polyvinylpyrrolidone (PVP).

[0012] The organic solvent is selected from N-methylpyrrolidone (NMP) or N,N-dimethylacetamide (DMAC).

[0013] In some technical solutions, the average particle size of the Fe and Ni metal powder is between 2 nm and 2000 nm.

[0014] On the other hand, the present invention further provides a method for preparing the above-mentioned Fe-Ni / polysulfone hollow fiber hybrid membrane, which has a simple process, high preparation efficiency, low cost, and is easy to industrialize.

[0015] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0016] Some technical solutions include the following steps:

[0017] Preparation of casting solution: Polysulfone is dissolved in an organic solvent and an appropriate amount of additives are added. Under suitable temperature conditions, the mixture is stirred and mixed evenly to form a homogeneous organic solution. Then, an appropriate amount of Fe and Ni metal powders are added and stirred and mixed evenly to obtain the casting solution.

[0018] Membrane spinning: After vacuum degassing, the casting solution is transferred to the supply tank and extruded through the spinneret under quantitative and constant speed delivery. After passing through an air gap, it enters the outer coagulation bath. At the same time, the inner coagulation bath is quantitatively and constant speed delivered to the spinneret. The fiber membrane undergoes solvent and non-solvent exchange under the action of the inner / outer coagulation baths, solidifies and forms, and is dried after washing with pure water to obtain the Fe-Ni / polysulfone hollow fiber hybrid membrane.

[0019] In some technical solutions, the external coagulation bath is pure water, and the temperature range of the external coagulation bath is 5℃~80℃.

[0020] In some technical solutions, the internal coagulation bath is pure water or an organic solution, wherein the organic solution is formed by mixing pure water and a polar solvent in a certain proportion.

[0021] In some technical solutions, the quantitative and constant-speed delivery can be achieved through a metering pump or through constant-pressure delivery; and / or,

[0022] The air gap is 0 to 80 cm.

[0023] In some technical solutions, the Fe-Ni / polysulfone hollow fiber hybrid membrane prepared has improved hydrophilicity and antifouling properties compared with polysulfone hollow fiber membrane.

[0024] In some technical solutions, the porosity of the prepared Fe-Ni / polysulfone hollow fiber hybrid membrane is 40%–85%, the tensile strength is 0.5–15 MPa, and the pure water flux is 10–40 mL / (m²) at 500 mmHg. 2 (·h·mmHg).

[0025] The present invention, by employing the above technical solution, has at least the following beneficial effects:

[0026] 1. The Fe-Ni / polysulfone hollow fiber hybrid membrane prepared in this application combines the characteristics of hollow fiber membranes and polysulfone membranes, exhibiting high packing density, high mechanical strength, and high clearance rate. Furthermore, the doped Fe and Ni metals possess inherent reducing and hydrophilic properties. The synergistic effect of the two metals not only improves the membrane structure and enhances its mechanical properties but also effectively improves the hydrophilicity and antifouling properties of the fiber membrane.

[0027] 2. The prepared Fe-Ni / polysulfone hollow fiber hybrid membrane has a porosity of 40%–85%, a tensile strength of 0.5–15 MPa, and a pure water flux of 10–40 mL / (m²) at 500 mmHg. 2 (·h·mmHg);

[0028] 3. The process of this application is simple, the preparation efficiency is high, the cost is low, and it is easy to industrialize. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings and their markings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 shows the relationship between ultrafiltration rate and time after metal doping in Examples 1-4 of this application;

[0031] Figure 2 shows the adsorption rate of BSA in the metal-doped films in Examples 1-4 of this application;

[0032] Figure 3 shows the surface / cross-section SEM images of the film after metal doping in the embodiments of this application;

[0033] Figure 4 is a comparison of the ultrafiltration rate over time in the embodiments of this application;

[0034] Figure 5 is a bar chart showing the flux reduction rate and recovery rate of each added membrane under extreme pollution conditions in the embodiments of this application. Detailed Implementation

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without creative effort. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0036] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0037] This application improves the mechanical properties, hydrophilicity, and antifouling properties of polysulfone fiber membranes by doping them with Fe and Ni metals.

[0038] Therefore, this application provides a casting solution composition for spinning Fe-Ni / polysulfone hollow fiber hybrid membranes, comprising, by mass percentage: 12% to 35% polysulfone, 0.5% to 30% additives, 0.5% to 30% Fe and Ni metal powders, and 40% to 90% organic solvents.

[0039] The additives can be hydrophilic polymers of polyethylene glycol (PEG) or polyvinylpyrrolidone (PVP); the organic solvents can be polar solvents of N-methylpyrrolidone (NMP) or N,N-dimethylacetamide (DMAC); and the average particle size of the Fe and Ni metal powders is between 2 nm and 2000 nm.

[0040] The Fe-Ni / polysulfone hollow fiber hybrid membrane in this embodiment combines the characteristics of both hollow fiber membranes and polysulfone membranes, exhibiting high packing density, high mechanical strength, and high removal rate. Furthermore, the Fe and Ni metals doped with the membrane possess certain reducing and hydrophilic properties. The synergistic effect of the two metals not only improves the membrane structure and enhances its mechanical properties but also effectively improves the hydrophilicity and antifouling properties of the fiber membrane.

[0041] This application also provides a method for preparing the above-mentioned Fe-Ni / polysulfone hollow fiber hybrid membrane, including the following steps:

[0042] Membrane material preparation: Weigh a certain amount of polysulfone particles and Fe-Ni metal powder and place them in an oven to dry at 60 ℃ for more than 24 hours.

[0043] Preparation of casting solution: Dissolve polysulfone in an organic solvent in a certain proportion, add an appropriate amount of additives, and stir and mix evenly under suitable temperature conditions to form a homogeneous organic solution. Then add Fe and Ni metal powder in a certain proportion, stir and mix evenly to obtain the casting solution.

[0044] Membrane spinning: After vacuum degassing, the casting solution is transferred to the supply tank and extruded through the spinneret under quantitative and constant speed delivery. After passing through an air gap, it enters the outer coagulation bath. At the same time, the inner coagulation bath is quantitatively and constant speed delivered to the spinneret. The fiber membrane undergoes solvent and non-solvent exchange under the action of the inner / outer coagulation baths, solidifies and forms, and is dried after washing with pure water to obtain the Fe-Ni / polysulfone hollow fiber hybrid membrane.

[0045] The choice between the internal and external coagulation baths is varied; either pure water or an organic solvent can be used. The organic solvent is formed by mixing pure water with a polar solvent in a specific ratio. Pure water allows for rapid exchange between the solvent and non-solvent, resulting in a well-defined internal porous structure. Specifically, the temperature range of the external coagulation bath is 5℃ to 80℃.

[0046] In one specific embodiment, the quantitative and constant-speed delivery can be carried out by a metering pump or by constant pressure delivery; the air gap through which the fiber membrane passes is 0 to 80 cm.

[0047] In this embodiment, the prepared Fe-Ni / polysulfone hollow fiber hybrid membrane has a porosity of 40%–85%, a tensile strength of 0.5–15 MPa, and a pure water flux of 10–40 mL / (m²) at 500 mmHg. 2 (·h·mmHg).

[0048] The performance of the Fe-Ni / polysulfone hollow fiber hybrid membrane prepared by the present invention is characterized and analyzed below with reference to specific embodiments.

[0049] Examples 1-4

[0050] According to the ratio PSU:PVP:DMAC:Fe:Ni=21:5:73:0.5:0.5, PSU was dissolved in the organic solvent DMAC, and the additive polyPVP was added. After mechanical stirring and mixing, a homogeneous organic solution was formed. Then, Fe-Ni / metal powder was added under stirring and mixed evenly to obtain the spinning solution. After vacuum degassing, the spinning solution was poured into the spinning device and pushed to the spinneret by a metering pump. At the same time, a 40% DMAC aqueous solution was used as the core liquid and entered the spinneret under pressure. After passing through an air gap, it entered the gel tank. The hollow fiber membrane was solidified and formed under the action of a non-solvent. After washing with pure water and drying, Fe-Ni / polysulfone hollow fiber membranes were obtained. By controlling the membrane area variable, the experimental groups of Fe-Ni / polysulfone hollow fiber membranes M1, M2, M3 and M4 shown in Table 1 were obtained.

[0051] Comparative Example 1

[0052] According to the ratio PSU:PVP:DMAC:X=21:5:73:0, PSU was dissolved in the organic solvent DMAC, and the additive polyPVP was added. After mechanical stirring and mixing evenly, a spinning solution was obtained. The spinning solution was degassed under vacuum and poured into the spinning device. It was pushed to the spinneret by a metering pump and formed. At the same time, a 40% DMAC aqueous solution was used as the core liquid and entered the spinneret under pressure. After passing through an air gap, it entered the gel tank. The hollow fiber membrane was solidified and formed under the action of a non-solvent. After washing with pure water and drying, the control group of polysulfone hollow fiber membranes shown in Table 1 was obtained.

[0053] Comparative Examples 2-3

[0054] According to the ratio PSU:PVP:DMAC:X=21:5:73:1, PSU was dissolved in the organic solvent DMAC, and the additive polyPVP was added. After mechanical stirring and mixing, a homogeneous organic solution was formed. Then, metal powder was added under stirring and mixed evenly to obtain the spinning solution. The spinning solution was degassed under vacuum and poured into the spinning device. It was pushed to the spinneret by a metering pump and formed. At the same time, a 40% DMAC aqueous solution was used as the core liquid and entered the spinneret under pressure. After passing through an air gap, it entered the gel tank. The hollow fiber membrane was solidified and formed under the action of a non-solvent. After washing with pure water and drying, a metal / polysulfone hollow fiber membrane was obtained. By changing the type of metal powder added, control groups of ZnO / polysulfone hollow fiber membranes and Fe2O3 / polysulfone hollow fiber membranes were prepared, as shown in Table 1.

[0055] Comparative Example 4

[0056] According to the ratio PSU:PVP:DMAC:Cu:Zn=21:5:73:0.5:0.5, PSU was dissolved in the organic solvent DMAC, and the additive polyPVP was added. After mechanical stirring and mixing, a homogeneous organic solution was formed. Then, metal powder was added under stirring and mixed evenly to obtain the spinning solution. After vacuum degassing, the spinning solution was poured into the spinning device and pushed to the spinneret by a metering pump. At the same time, a 40% DMAC aqueous solution was used as the core liquid and pushed into the spinneret under pressure. After passing through an air gap, it entered the gel tank, where the hollow fiber membrane solidified under the action of a non-solvent. After washing with pure water and drying, the Cu-Zn / polysulfone hollow fiber membrane control group shown in Table 1 was obtained.

[0057]

[0058] See Figure 1 The figure shows the relationship between the ultrafiltration rate and time for Fe-Ni / polysulfone hollow fiber membranes with different membrane areas in experimental groups 1-4. As can be seen from the figure, the ultrafiltration rate of the polysulfone hollow fiber hybrid membranes doped with Fe and Ni metals shows a slight decreasing trend over time, and the overall ultrafiltration rate remains at 50 mL·h. -1 ·mmHg -1 The above points are relevant; furthermore, the filtration performance of Fe-Ni / polysulfone hollow fiber membranes is improved as the effective membrane area increases.

[0059] Please refer to Table 2, which shows the removal efficiency of Fe-Ni / polysulfone hollow fiber membranes prepared in experimental groups 1-4 for various pollutants. The removal efficiency slightly improves with increasing effective membrane area, and all meet the requirements of the application scenarios.

[0060]

[0061] See Figure 2 The adsorption effect of Fe-Ni / polysulfone hollow fiber membranes prepared in experimental groups 1-4 on BSA is shown. Referring to Table 3, compared with control groups 1-4, the BSA adsorption rates of the experimental groups in this study were all below 10 μg·cm⁻¹. -3 Since a higher adsorption rate results in a lower antifouling performance, the Fe and Ni metal-doped polysulfone hollow fiber membrane in this study exhibits significantly improved antifouling performance. Table 3 further shows that, compared to control groups 1-4, the membranes in this experimental group have a smaller contact angle and can withstand a higher breaking load, thus possessing superior mechanical and hydrophilic properties.

[0062]

[0063] Figure 3The SEM images of the film surface / cross section after metal doping are shown. It can be seen that metal doping did not have a significant impact on the film structure, and the cross section of the film still exhibits an asymmetric sponge layer structure.

[0064] Figure 4 The figure shows the relationship between the ultrafiltration rate of the polysulfone hollow fiber membranes in the control group and the experimental group and time. As can be seen from the figure, the ultrafiltration rate of the Fe-Ni / polysulfone hollow fiber membrane in this case is much higher than that of the polysulfone hollow fiber membranes in the control group 1-4, and the decreasing trend of the ultrafiltration rate with time is also more gradual, indicating a significant improvement in its filtration performance.

[0065] Figure 5 The diagram shows the flux reduction rate and recovery rate of each added membrane under extreme pollution scenarios. It can be seen that the Fe-Ni / polysulfone hollow fiber membrane in this case exhibits the lowest flux reduction rate and the highest recovery rate under severe pollution conditions, demonstrating excellent antifouling performance.

[0066] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

[0067] Those skilled in the art should understand that although the present invention has been described with reference to multiple embodiments, not every embodiment contains only one independent technical solution. This description is provided merely for clarity; those skilled in the art should understand the specification as a whole and consider the technical solutions involved in each embodiment as being able to be combined with each other to form different embodiments to understand the scope of protection of the present invention.

Claims

1. A Fe-Ni / polysulfone hollow fiber hybrid membrane, characterized in that, The Fe-Ni / polysulfone hollow fiber hybrid membrane is obtained by spinning a casting solution into fibers using a spinning device and then undergoing post-treatment. The casting solution is prepared as follows: a polysulfone polymer is dissolved in an organic solvent, and an appropriate amount of additives are added. Under suitable temperature conditions, the mixture is stirred and mixed evenly to form a homogeneous organic solution. Then, an appropriate amount of Fe and Ni metal powder is added, and the mixture is stirred and mixed evenly to obtain the casting solution. The casting solution is degassed under vacuum and transferred to a supply tank. It is then extruded through a spinneret under a quantitative and constant-speed feed, passing through an air gap before entering an external coagulation bath. Simultaneously, an internal coagulation bath is quantitatively and at a constant speed fed to the spinneret. The fiber membrane undergoes solvent and non-solvent exchange under the action of the internal / external coagulation baths, solidifies, and is washed with pure water and dried to obtain the Fe-Ni / polysulfone hollow fiber hybrid membrane. The casting solution is composed of the following components, each by mass percentage: 12%–35% polysulfone polymer, 0.5%–30% additives, 0.5%–30% Fe and Ni metal powder, and 40%–90% organic solvent; The Fe-Ni / polysulfone hollow fiber hybrid membrane is used for blood purification, and the porosity of the Fe-Ni / polysulfone hollow fiber hybrid membrane is 40% to 85%.

2. The Fe-Ni / polysulfone hollow fiber hybrid membrane according to claim 1, characterized in that, The additive is a hydrophilic polymer; and / or, The organic solvent is a polar solvent.

3. The Fe-Ni / polysulfone hollow fiber hybrid membrane according to claim 2, characterized in that, The additive is selected from polyethylene glycol or polyvinylpyrrolidone; The organic solvent is selected from N-methylpyrrolidone or N,N-dimethylacetamide.

4. The Fe-Ni / polysulfone hollow fiber hybrid membrane according to claim 1, characterized in that, The average particle size of the Fe and Ni metal powders is between 2 nm and 2000 nm.

5. A method for preparing a Fe-Ni / polysulfone hollow fiber hybrid membrane as described in any one of claims 1-4, characterized in that, The preparation method includes the casting solution preparation step, the spinning and forming step, and the post-treatment step as described in claim 1.

6. The preparation method according to claim 5, characterized in that, The external coagulation bath is pure water, and the temperature range of the external coagulation bath is 5℃~80℃.

7. The preparation method according to claim 5, characterized in that, The internal coagulation bath is pure water or an organic solution, wherein the organic solution is formed by mixing pure water and a polar solvent in a certain proportion.

8. The preparation method according to claim 5, characterized in that, The aforementioned quantitative and constant-speed delivery is achieved through a metering pump or through constant pressure delivery; and / or, The air gap is 0 to 80 cm.

9. The preparation method according to claim 5, characterized in that, The Fe-Ni / polysulfone hollow fiber hybrid membrane has a tensile strength of 0.5–15 MPa and a pure water flux of 10–40 mL / (m²) at 500 mmHg. 2 (·h·mmHg).

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