Preparation method of PAN-based oil-water separation membrane with excellent antibacterial property and chlorine resistance

Abstract

The invention discloses a preparation method of a PAN-based oil-water separation membrane with excellent antibacterial property and chlorine resistance. The preparation method comprises the following steps: step 1, preparing a meltable PAN-based terpolymer; 2, melting the meltable PAN-based terpolymer, the composite diluent, the hydrophilic modifier, the antibacterial functional salt and the surfactant to form a homogeneous membrane casting solution; step 3, preparing a salt-doped PAN-based oil-water separation membrane from the membrane casting solution through a thermally induced phase separation method; and 4, carrying out ultraviolet radiation on the salt-doped PAN-based oil-water separation membrane, and reducing salt ions in a membrane matrix into metal nanoparticles to obtain the PAN-based oil-water separation membrane with excellent antibacterial property and chlorine resistance. The PAN-based oil-water separation membrane with excellent antibacterial property, chlorine resistance, illumination resistance, chemical stability, mechanical property, oil-water separation performance and cycling stability, high flux and high interception efficiency is obtained through a blending method.

Description

Technical Field

[0001] This invention belongs to the field of oil-water separation membrane technology, specifically a method for preparing a PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties. Background Technology

[0002] With societal development, the discharge of industrial wastewater, domestic sewage, and oil-water mixtures from oil extraction, refining, food processing, and machinery manufacturing, as well as from marine oil spills, is increasing daily. Direct discharge without treatment will pollute water bodies, damage ecosystems (e.g., oil films covering the water surface causing oxygen depletion in aquatic organisms), and even endanger human health through the food chain. Traditional separation technologies, including centrifugation, adsorption, and chemical demulsification, suffer from low efficiency, high energy consumption, secondary pollution, or inability to handle emulsified oils. Membrane separation technology can efficiently separate micron / nano-sized oil droplets, especially suitable for emulsified oils. Furthermore, some of the separated oil phase can be purified and reused, reducing production costs. The treated water meets discharge standards or can be recycled, alleviating water scarcity.

[0003] Application No. 202111528680.0 discloses a method for preparing an ultra-amphiphilic oleophilic water separation membrane with fixed in-situ growth of silver nanoparticles. The method involves dissolving a polymer membrane substrate in an organic solvent, then adding a hydrophilic modifier, crosslinking agent, and initiator, stirring to dissolve, and allowing to stand to remove bubbles to obtain a casting solution. The casting solution is then coated onto a polymer support layer, and the membrane is immersed in a silver ammonia solution. A glucose solution is then added to the silver ammonia solution, and a phase inversion is performed at 25-60°C for 2-60 minutes. Afterward, the membrane is removed, washed, and dried to obtain the ultra-amphiphilic oleophilic water separation membrane. However, this method introduces silver ions to the membrane surface and reduces them to silver nanoparticles fixed on the membrane surface using a solvent. The permeability of the glucose solution on the membrane surface is limited, limiting the conversion rate of Ag nanoparticles. Furthermore, since there is no interaction between the silver nanoparticles loaded on the membrane surface and the membrane substrate, the silver nanoparticles easily detach from the carrier surface during actual operation, resulting in a decrease in the membrane's antibacterial effect. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing a PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties.

[0005] The technical solution of this invention to solve the aforementioned technical problem is to provide a method for preparing a PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties, characterized in that the method includes the following steps: Step 1: Preparation of meltable PAN-based terpolymers: Emulsifying n-dodecyl mercaptan, OP-10, SDS, and deionized water yields an emulsion. The monomers, emulsion, and an initiator aqueous solution are reacted to obtain a mixture. The monomers consist of acrylonitrile, a second monomer, and an unsaturated UV-sensitive crosslinking agent. The mixture is then mixed with a magnesium sulfate aqueous solution for demulsification to obtain the product. The product is then filtered, retaining the solid. The solid is washed with deionized water and filtered again to remove impurities and unreacted substances. After drying, a meltable PAN-based terpolymer is obtained. Step 2: Melt the fusible PAN-based terpolymer, composite diluent, hydrophilic modifier, antibacterial functional salt, and surfactant to form a homogeneous casting solution; Step 3: Preparation of PAN-based oil-water separation membrane with salt dopant: The casting solution obtained in Step 2 is used to prepare a PAN-based oil-water separation membrane with salt dopant by thermal induced phase separation method. Step 4: Preparation of PAN-based oil-water separation membrane with excellent antibacterial and chlorine resistance: The PAN-based oil-water separation membrane with doped salt prepared in Step 3 is subjected to ultraviolet irradiation to reduce the salt ions in the membrane matrix to metal nanoparticles, thereby obtaining a PAN-based oil-water separation membrane with excellent antibacterial and chlorine resistance.

[0006] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention introduces hydrophilic modifier, antibacterial agent and surfactant simultaneously through blending, and then obtains PAN-based oil-water separation membrane with excellent antibacterial properties, chlorine resistance, light resistance, chemical stability, mechanical properties, oil-water separation performance and cycle stability through TIPS method.

[0007] (2) In the preparation stage of the casting solution, during the blending of the polymer and the filler, the salt interacts with the cyano group (-CN) to form the film. During the film formation process, the surface and interior of the hydrophilic PAN-based oil-water separation membrane interact, which can effectively prevent the metal nanoparticles with antibacterial function from falling off during application. Moreover, the salt is uniformly dispersed in the PAN matrix, avoiding the agglomeration problem that occurs when nanofillers are directly mixed in, thus enhancing the stability of the membrane.

[0008] (3) The PAN-based oil-water separation membrane prepared by this invention has excellent antibacterial properties due to the introduction of metal nanoparticles, which inhibits microbial contamination (such as bacterial biofilm formation) and extends the service life of the membrane. Moreover, the bactericidal response speed of the nanoparticles is higher than that of other common antibacterial agents, and it has excellent antibacterial / bactericidal effects on a variety of bacteria. At the same time, the release amount is more stable, and the synergistic effect with the hydrophilic groups of other fillers in this patent can improve the hydrophilicity of the membrane.

[0009] (4) Adding an appropriate amount of anionic surfactant during the membrane fabrication process can regulate the microporous structure of the membrane through self-assembly behavior, thereby optimizing the separation efficiency. Simultaneously, anionic surfactants are also hydrophilic emulsifiers, which help improve salt dispersibility during the preparation of the casting solution. Their amphiphilic structure can reduce salt ion aggregation, ensuring uniform distribution of salt ions within the membrane channels. Furthermore, SDS can reduce the water contact angle on the membrane surface, improving the membrane's hydrophilicity and underwater oleophobic properties. Moreover, SDS is inexpensive, allowing for large-scale production.

[0010] (5) Traditional PAN oil-water separation membranes have limited effect on separating emulsified oils, but after adding SDS and salt, they can efficiently treat wastewater containing surfactants, high salinity or microbial contamination.

[0011] (6) The hydrophilic modifier is eco-friendly and contains multiple hydroxyl groups (-OH), which can form hydrogen bonds with -CN in the polymer and generate interaction forces.

[0012] (7) Compared with traditional modification methods (such as plasma treatment, multilayer coating, etc.), the present invention achieves multifunctionality of the separation membrane through a one-step blending method, which simplifies the process and reduces costs. Attached Figure Description

[0013] Figure 1 This is a SEM image of the PAN-based oil-water separation membrane prepared in Example 1 of the present invention; Figure 2 EDS image of the PAN-based oil-water separation membrane prepared in Example 1 of this invention; Figure 3 The PAN-based oil-water separation membranes prepared for the control group (a), comparative example 1 (b), and example 1 (c) of this invention were diluted (a1, b1, c1) by 10. 4 (a2, b2, c2) 10 5 and (a3, b3, c3) 10 6 Graph showing the antibacterial effect of the multi-bacterial solution; Figure 4 The chlorine resistance of the PAN-based oil-water separation membranes prepared in Comparative Example 2, Example 16, Example 1, and Example 17 of this invention is shown in the figure. Figure 5 The diagram shows the pure water flux of the PAN-based oil-water separation membranes prepared in Comparative Example 2, Example 16, Example 1 and Example 17 of this invention. Figure 6 This is a test image of the dynamic oil adhesion performance of the PAN-based oil-water separation membrane prepared in Example 1 of the present invention under water. Figure 7 The graph shows the separation performance of the PAN-based oil-water separation membrane prepared in Example 1 of this invention for different oil-in-water and water-in-oil emulsions. Detailed Implementation

[0014] Specific embodiments of the present invention are given below. These specific embodiments are only used to further illustrate the present invention in detail and do not limit the scope of protection of the present invention.

[0015] This invention provides a method for preparing a PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties (hereinafter referred to as the method), characterized in that the method includes the following steps: Step 1: Preparation of meltable PAN-based terpolymers: Emulsifying n-dodecyl mercaptan, OP-10, SDS (sodium dodecyl sulfate), and deionized water yields an emulsion. The monomers, emulsion, and an initiator aqueous solution are reacted to obtain a mixture. The monomers consist of acrylonitrile, a second monomer, and an unsaturated UV-sensitive crosslinking agent. The mixture is then mixed with a magnesium sulfate aqueous solution for demulsification to obtain the product. The product is then filtered, retaining the solid. The solid is washed with deionized water and filtered again until all impurities and unreacted substances are completely removed. After drying, a meltable PAN-based terpolymer is obtained. Preferably, in step 1, the emulsification process is as follows: the temperature is room temperature (i.e., 20~30℃) and the time is 20~60min.

[0016] Preferably, in step 1, the molar ratio of n-dodecyl mercaptan to the polymerizing monomer is 0.4~0.6%, the molar ratio of OP-10 to the polymerizing monomer is 0.1~0.3%, the molar ratio of SDS to the polymerizing monomer is 0.1~0.3%, and the mass of deionized water in the emulsion is 100~150% (preferably 140%) of the mass of the polymerizing monomer.

[0017] Preferably, in step 1, the second monomer is at least one of methyl acrylate (MA), methyl methacrylate, itaconic acid, and vinylimidazole; Preferably, in step 1, the unsaturated UV-sensitive crosslinking agent is at least one of ABP (4-acryloyloxybenzophenone), AHBP (2-hydroxy-4-acryloyloxybenzophenone), OBZ (2-hydroxy-4-methoxybenzophenone), BPM (4-methacryloyloxybenzophenone), and OCP (stearyl benzophenone).

[0018] Preferably, in step 1, the molar ratio of acrylonitrile, the second monomer, and the unsaturated UV-sensitive crosslinking agent is 85~95:5~15:1~5.

[0019] Preferably, in step 1, the polymerization inhibitor is first removed from the polymerized monomer by passing it through an activated alumina column.

[0020] Preferably, in step 1, the initiator aqueous solution is prepared by dissolving the initiator in deionized water; the initiator is ammonium persulfate or a mixture of ammonium persulfate and sodium bisulfite; the molar ratio of ammonium persulfate to the polymer monomer is 0.05~0.1%; and the molar ratio of sodium bisulfite to the polymer monomer is 0~0.03%.

[0021] Preferably, in step 1, the reaction process is as follows: the environment is an oxygen-free environment (preferably an inert gas environment or a nitrogen environment, the inert gas being argon or helium), the temperature is 45~50℃, the stirring speed is 400~500r / min, and the time is 10~15h.

[0022] Preferably, in step 1, the magnesium sulfate aqueous solution is prepared by dissolving anhydrous magnesium sulfate in deionized water; the mass fraction of the magnesium sulfate aqueous solution is 10~15wt%; the mass of deionized water in the magnesium sulfate aqueous solution is 250~300% (preferably 280%) of the emulsion mass.

[0023] Preferably, in step 1, the demulsification process is: standing at room temperature for 10-15 hours.

[0024] Preferably, in step 1, the process of washing the solid with deionized water and then filtering is repeated 2 to 5 times.

[0025] Preferably, in step 1, the drying process is carried out at a temperature of 50~70℃ for a time of 12~48h, preferably in a vacuum drying oven.

[0026] Step 2: Melt the fusible PAN-based terpolymer, composite diluent, hydrophilic modifier, antibacterial functional salt, and surfactant to form a homogeneous casting solution; Preferably, in step 2, the composite diluent is composed of CPL (caprolactam) and GTA (triacetin), and the mass ratio of the two is arbitrary, preferably 1:1; Preferably, in step 2, the hydrophilic modifier is one of sorbitol (SBT), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), chitosan, glycerol, xylitol, polyglycerol, polyethylene glycol (PEG), polyvinyl alcohol (PVA), tannic acid, sucrose ester, phytic acid (HA), or β-cyclodextrin (β-CD).

[0027] Preferably, in step 2, the antibacterial functional salt is one of silver nitrate (AgNO3), silver sulfate (Ag2SO4), silver carbonate (Ag2CO3), copper nitrate (Cu(NO3)2), copper sulfate (CuSO4), zinc nitrate (Zn(NO3)2), zinc chloride (ZnCl2), sodium hypochlorite (NaClO), or calcium hypochlorite (Ca(ClO)2).

[0028] Preferably, in step 2, the surfactant is an anionic emulsifier, preferably one of sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), sulfonated polyethersulfone (SPES), sodium fatty alcohol polyoxyethylene ether sulfate (AES), sodium stearate, sodium polyacrylate, alkyl phosphate salts, perfluorooctane sulfonate, or lignin sulfonate.

[0029] Preferably, in step 2, the mass of the composite diluent accounts for 65-85% of the mass of the casting solution; the mass of the fusible PAN-based terpolymer accounts for 15-35% of the mass of the composite diluent; the mass of the hydrophilic modifier accounts for 0.5-5% of the mass of the fusible PAN-based terpolymer; the mass of the antibacterial functional salt accounts for 0.5-3% of the mass of the fusible PAN-based terpolymer; and the mass of the surfactant accounts for 0.5-3% of the mass of the fusible PAN-based terpolymer.

[0030] Preferably, in step 2, the melting process is as follows: stirring is used until all components are completely melted in an oxygen-free environment, the stirring speed is 450~600ppm, the stirring time is 3~5h, and the stirring temperature is 150~200℃. Preferably, this is carried out in a magnetic stirrer.

[0031] Preferably, in step 2, the oxygen-free environment is an inert gas environment or a nitrogen environment (preferably a nitrogen environment), and the inert gas is argon or helium.

[0032] Step 3: Preparation of PAN-based oil-water separation membrane with salt dopant: The casting solution obtained in Step 2 is used to prepare a PAN-based oil-water separation membrane with salt dopant by thermally induced phase separation (TIPS). Preferably, in step 3, the thermally induced phase separation method specifically involves: transferring the casting solution to an environment at 150~200℃ and maintaining the temperature for 10~20 minutes to allow the casting solution to flow; then transferring it to an air bath at 25~30℃ to allow the casting solution to undergo phase separation and solidification; after complete solidification, immersing it in deionized water for 24~48 hours to remove the composite diluent, and then drying it at 40~80℃ for 4~8 hours to obtain a PAN-based oil-water separation membrane doped with salt.

[0033] Step 4: Preparation of PAN-based oil-water separation membrane with excellent antibacterial and chlorine resistance: The PAN-based oil-water separation membrane with doped salt prepared in Step 3 is subjected to ultraviolet irradiation to reduce the salt ions in the membrane matrix to metal nanoparticles, thereby obtaining a PAN-based oil-water separation membrane with excellent antibacterial and chlorine resistance.

[0034] Preferably, in step 4, the ultraviolet irradiation process is as follows: the ultraviolet light power is 1000~3000W, and the irradiation time is 5~15min.

[0035] The testing method in the embodiment is as follows: Oil-water separation performance test: A separation experiment was conducted on a 1% oil-in-water toluene emulsion using dead-end filtration. The flux and efficiency of the oil-water separation were calculated using the following formula:

[0036] In the formula, J w V, A, t, c0, and c represent the membrane flux (L / m³). 2 •h), filtrate volume (L), effective membrane area (m²) 2 The parameters included running time (h), the content of dispersed phase in the emulsion, and the content of dispersed phase in the corresponding filtrate. For water-in-oil and water-in-water emulsions, the absorption peak intensity of toluene in the emulsion and filtrate was measured using ultraviolet spectroscopy, and the oil-water separation efficiency was calculated.

[0037] In the test, the water-in-oil emulsion was a stable water-in-petroleum ether emulsion with added surfactant, and the oil-in-water emulsion was a carbon tetrachloride-in-water emulsion with added surfactant.

[0038] Example 1: (1) Preparation of meltable PAN-based terpolymer: n-dodecyl mercaptan, OP-10, SDS and deionized water were mixed and emulsified at room temperature for 30 min to obtain an emulsion; the molar ratio of n-dodecyl mercaptan to the monomer was 0.5%, the molar ratio of OP-10 to the monomer was 0.2%, the molar ratio of SDS to the monomer was 0.2%, and the mass of deionized water in the emulsion was 140% of the mass of the monomer; the molar ratio of acrylonitrile, MA and ABP was 85:10:5; Sodium bisulfite and ammonium persulfate were dissolved in deionized water to prepare an initiator aqueous solution; the molar ratio of ammonium persulfate to monomer was 0.05%; the molar ratio of sodium bisulfite to monomer was 0.03%. Anhydrous magnesium sulfate was dissolved in deionized water to prepare an aqueous magnesium sulfate solution; the mass fraction of the aqueous magnesium sulfate solution was 12 wt%; the mass of deionized water in the aqueous magnesium sulfate solution was 280% of the mass of the emulsion. Acrylonitrile, MA, and ABP were subjected to oxidation by passing them through an activated alumina column to remove the polymerization inhibitors. The mixture was then reacted with an emulsion and an initiator aqueous solution at 480 rpm and 48°C for 12 h under nitrogen atmosphere to obtain a mixed solution. This mixed solution was then mixed with a magnesium sulfate aqueous solution and allowed to stand at room temperature for 12 h to demulsify, yielding the product. The product was then filtered, the waste liquid was discarded, and the solid was retained. The solid was washed with deionized water and filtered again, repeated three times. Finally, the solid was dried in a vacuum oven at 60°C for 24 h to obtain a fusible PAN-based terpolymer. (2) The fusible PAN-based terpolymer (15% of the mass of the composite diluent), the composite diluent with a mass ratio of CPL and GTA of 1:1 (85% of the mass of the casting solution), SBT (2% of the mass of the fusible PAN-based terpolymer), AgNO3 (0.5% of the mass of the fusible PAN-based terpolymer), and SDS (1% of the mass of the fusible PAN-based terpolymer) were stirred continuously at 180°C and 500 ppm for 4 hours under nitrogen protection to form a homogeneous casting solution. (3) Quickly pour the casting solution into a double-layer glass mold and clamp the glass with clamps. Then transfer the mold to an oven at 180°C and keep it at a constant temperature for 15 minutes. Then transfer it to an air bath at 27°C to allow the casting solution to undergo phase separation and solidification. After complete solidification, remove the mold, soak the membrane in deionized water for 24 hours to remove the composite diluent, and then dry it at 60°C for 4 hours to obtain a PAN-based oil-water separation membrane doped with salt. (4) Irradiate the salt-doped PAN-based oil-water separation membrane under 2000W ultraviolet light for 10 min to reduce the salt ions in the membrane matrix to Ag nanoparticles, thereby obtaining a PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties.

[0039] Depend on Figure 1 As can be seen, the surface of the PAN-based oil-water separation membrane in Example 1 has a loose porous structure.

[0040] Depend on Figure 2 It can be seen that C, N, O and Ag elements are present on the surface and inside the membrane, proving the introduction of Ag element.

[0041] Depend on Figure 3 It can be seen that the number of Staphylococcus aureus colonies in the PAN-based oil-water separation membrane with added AgNO3 (Example 1) is significantly less than that in the PAN-based oil-water separation membrane without added antibacterial functional salt (Comparative Example 1).

[0042] Depend on Figure 4 It can be seen that after stirring in a 200ppm sodium hypochlorite solution for 24 hours, the flux of the PAN-based oil-water separation membrane after ultraviolet irradiation for different times did not decrease significantly, and the separation efficiency was not significantly affected. The separation efficiency of Examples 16, 1, and 17 was improved compared with Comparative Example 2.

[0043] Depend on Figure 5 It can be seen that the pure water flux of the membrane decreases with the extension of external irradiation time.

[0044] Depend on Figure 6 It can be seen that Example 1 is oleophobic underwater, with contact angles greater than 150° for both light oil (n-hexane) and heavy oil (dichloromethane), which is more conducive to improving the oil-water separation efficiency of the membrane.

[0045] Depend on Figure 7 It can be seen that the membrane prepared in Example 1 has high separation flux and separation efficiency for both oil-in-water emulsions with and without emulsifiers.

[0046] Comparative Example 1: It is exactly the same as Example 1, except that in step 2, no antibacterial functional salt is added.

[0047] Comparative Example 2: It is exactly the same as Example 1, except that in step 4, the ultraviolet irradiation time is 0 min.

[0048] Comparative Example 3: It is exactly the same as Example 1, except that no surfactant is added in step 2.

[0049] Example 2: It is exactly the same as Example 1, except that in step 1, the second monomer is itaconic acid.

[0050] Example 3: It is exactly the same as Example 1, except that in step 1, the unsaturated ultraviolet light-sensitive crosslinking agent is AHBP.

[0051] Example 4: It is exactly the same as Example 1, except that in step 1, the molar ratio of acrylonitrile, the second monomer and the unsaturated UV-sensitive crosslinking agent is 88:10:2.

[0052] Example 5: It is exactly the same as Example 1, except that in step 1, the molar ratio of acrylonitrile, the second monomer and the unsaturated UV-sensitive crosslinking agent is 90:5:5.

[0053] Example 6: It is exactly the same as Example 1, except that in step 1, the emulsification time is 60 min.

[0054] Example 7: It is exactly the same as Example 1, except that in step 2, the amount of hydrophilic modifier added is 1%.

[0055] Example 8: It is exactly the same as Example 1, except that in step 2, the mass of the hydrophilic modifier accounts for 3% of the mass of the meltable PAN-based terpolymer.

[0056] Example 9: It is exactly the same as Example 1, except that in step 2, the mass of the hydrophilic modifier accounts for 4% of the mass of the meltable PAN-based terpolymer.

[0057] Example 10: It is exactly the same as Example 1, except that in step 2, the mass of the hydrophilic modifier accounts for 5% of the mass of the meltable PAN-based terpolymer.

[0058] Example 11: It is exactly the same as Example 1, except that in step 2, the mass of the antibacterial functional salt accounts for 1.5% of the mass of the fusible PAN-based terpolymer.

[0059] Example 12: It is exactly the same as Example 1, except that in step 2, the mass of the antibacterial functional salt accounts for 2.5% of the mass of the molten PAN-based terpolymer.

[0060] Example 13: It is exactly the same as Example 1, except that in step 2, the mass of the surfactant accounts for 0.5% of the mass of the meltable PAN-based terpolymer.

[0061] Example 14: It is exactly the same as Example 1, except that in step 2, the mass of the surfactant accounts for 1.5% of the mass of the meltable PAN-based terpolymer.

[0062] Example 15: It is exactly the same as Example 1, except that in step 2, the mass of the surfactant accounts for 2.5% of the mass of the meltable PAN-based terpolymer.

[0063] Example 16: It is exactly the same as Example 1, except that in step 4, the ultraviolet irradiation time is 5 minutes.

[0064] Example 17: It is exactly the same as Example 1, except that in step 4, the ultraviolet irradiation time is 15 minutes.

[0065] Example 18: It is exactly the same as Example 1, except that in step 2, the antibacterial functional salt is Ag2SO4.

[0066] Example 19: It is exactly the same as Example 1, except that in step 2, the antibacterial functional salt is Ag2CO3.

[0067] Example 20: It is exactly the same as Example 1, except that in step 2, the antibacterial functional salt is Cu(NO3)2.

[0068] Example 21: It is exactly the same as Example 1, except that in step 2, the antibacterial functional salt is CuSO4.

[0069] Example 22: It is exactly the same as Example 1, except that in step 2, the antibacterial functional salt is Zn(NO3)2.

[0070] Example 23: It is exactly the same as Example 1, except that in step 2, the antibacterial functional salt is ZnCl2.

[0071] Example 24: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier is PVA.

[0072] Example 25: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier is PEG-1000.

[0073] Example 26: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier is tannic acid.

[0074] Example 27: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier is CMC.

[0075] Example 28: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier used is HEC.

[0076] Example 29: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier is glycerol.

[0077] Example 30: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier is sucrose ester.

[0078] Example 31: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier is HA.

[0079] Example 32: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier is β-CD.

[0080] Example 33: It is exactly the same as Example 1, except that in step 2, xylitol is used as the hydrophilic modifier.

[0081] Example 34: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier is polyglycerol.

[0082] Example 35: It is exactly the same as Example 1, except that in step 2, the hydrophilic modifier is chitosan.

[0083] Table 1

[0084]

[0085] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A method for preparing a PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties, characterized in that, The method includes the following steps: Step 1: Preparation of meltable PAN-based terpolymers: Emulsifying n-dodecyl mercaptan, OP-10, SDS, and deionized water yields an emulsion. The monomers, emulsion, and an initiator aqueous solution are reacted to obtain a mixture. The monomers consist of acrylonitrile, a second monomer, and an unsaturated UV-sensitive crosslinking agent. The mixture is then mixed with a magnesium sulfate aqueous solution for demulsification to obtain the product. The product is then filtered, retaining the solid. The solid is washed with deionized water and filtered again to remove impurities and unreacted substances. After drying, a meltable PAN-based terpolymer is obtained. Step 2: Melt the fusible PAN-based terpolymer, composite diluent, hydrophilic modifier, antibacterial functional salt, and surfactant to form a homogeneous casting solution; Step 3: Preparation of PAN-based oil-water separation membrane with salt dopant: The casting solution obtained in Step 2 is used to prepare a PAN-based oil-water separation membrane with salt dopant by thermal induced phase separation method. Step 4: Preparation of PAN-based oil-water separation membrane with excellent antibacterial and chlorine resistance: The PAN-based oil-water separation membrane with doped salt prepared in Step 3 is subjected to ultraviolet irradiation to reduce the salt ions in the membrane matrix to metal nanoparticles, thereby obtaining a PAN-based oil-water separation membrane with excellent antibacterial and chlorine resistance.

2. The method for preparing the PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties according to claim 1, characterized in that, In step 1, the emulsification process is as follows: the temperature is room temperature, and the time is 20~60 minutes; In step 1, the molar ratio of n-dodecyl mercaptan to the monomer is 0.4~0.6%, the molar ratio of OP-10 to the monomer is 0.1~0.3%, the molar ratio of SDS to the monomer is 0.1~0.3%, and the mass of deionized water in the emulsion is 100~150% of the mass of the monomer.

3. The method for preparing the PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties according to claim 1, characterized in that, In step 1, the second monomer is at least one of methyl acrylate, methyl methacrylate, itaconic acid, and vinylimidazole; In step 1, the unsaturated UV-sensitive crosslinking agent is at least one of ABP, AHBP, OBZ, BPM, and OCP; In step 1, the molar ratio of acrylonitrile, the second monomer, and the unsaturated UV-sensitive crosslinking agent is 85~95:5~15:1~5.

4. The method for preparing the PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties according to claim 1, characterized in that, In step 1, the initiator aqueous solution is prepared by dissolving the initiator in deionized water; the initiator is ammonium persulfate or a mixture of ammonium persulfate and sodium bisulfite; the molar ratio of ammonium persulfate to the monomer is 0.05~0.1%; the molar ratio of sodium bisulfite to the monomer is 0~0.03%; In step 1, the magnesium sulfate aqueous solution is prepared by dissolving anhydrous magnesium sulfate in deionized water; the mass fraction of the magnesium sulfate aqueous solution is 10~15wt%; the mass of the deionized water in the magnesium sulfate aqueous solution is 250~300% of the mass of the emulsion.

5. The method for preparing the PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties according to claim 1, characterized in that, In step 1, the reaction process is as follows: the environment is an oxygen-free environment, the temperature is 45~50℃, the stirring speed is 400~500r / min, and the time is 10~15h; In step 1, the demulsification process is: let it stand at room temperature for 10-15 hours; In step 1, the process of washing the solid with deionized water and then filtering it is repeated 2 to 5 times. In step 1, the drying process is as follows: temperature 50~70℃, time 12~48h.

6. The method for preparing the PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties according to claim 1, characterized in that, In step 2, the composite diluent consists of CPL and GTA, and the mass ratio of the two is arbitrary; In step 2, the hydrophilic modifier is one of the following: sorbitol, carboxymethyl cellulose, hydroxyethyl cellulose, chitosan, glycerol, xylitol, polyglycerol, polyethylene glycol, polyvinyl alcohol, tannic acid, sucrose ester, phytic acid, or β-cyclodextrin. In step 2, the antibacterial functional salt is one of silver nitrate, silver sulfate, silver carbonate, copper nitrate, copper sulfate, zinc nitrate, zinc chloride, sodium hypochlorite, or calcium hypochlorite. In step 2, the surfactant is an anionic emulsifier, preferably one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sulfonated polyethersulfone, sodium fatty alcohol polyoxyethylene ether sulfate, sodium stearate, sodium polyacrylate, alkyl phosphate salt, perfluorooctane sulfonate, or lignin sulfonate.

7. The method for preparing the PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties according to claim 1, characterized in that, In step 2, the mass of the composite diluent accounts for 65-85% of the mass of the casting solution; the mass of the fusible PAN-based terpolymer accounts for 15-35% of the mass of the composite diluent; the mass of the hydrophilic modifier accounts for 0.5-5% of the mass of the fusible PAN-based terpolymer; the mass of the antibacterial functional salt accounts for 0.5-3% of the mass of the fusible PAN-based terpolymer; and the mass of the surfactant accounts for 0.5-3% of the mass of the fusible PAN-based terpolymer.

8. The method for preparing the PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties according to claim 1, characterized in that, In step 2, the melting process is as follows: stirring is used until all components are completely melted. In an oxygen-free environment, the stirring speed is 450~600ppm, the stirring time is 3~5h, and the stirring temperature is 150~200℃. In step 2, the oxygen-free environment is an inert gas environment or a nitrogen environment, and the inert gas is argon or helium.

9. The method for preparing the PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties according to claim 1, characterized in that, In step 3, the thermally induced phase separation method specifically involves: transferring the casting solution to an environment at 150~200℃ and holding it at that temperature for 10~20 minutes to allow the casting solution to flow; then transferring it to an air bath at 25~30℃ to allow the casting solution to undergo phase separation and solidification; after complete solidification, immersing it in deionized water for 24~48 hours to remove the composite diluent, and then drying it at 40~80℃ for 4~8 hours to obtain a PAN-based oil-water separation membrane doped with salt.

10. The method for preparing the PAN-based oil-water separation membrane with excellent antibacterial and chlorine-resistant properties according to claim 1, characterized in that, In step 4, the ultraviolet irradiation process is as follows: the ultraviolet light power is 1000~3000W, and the irradiation time is 5~15min.

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