Polyphenylene sulfide-based oil-water separation film and preparation method thereof

Abstract

The invention provides a polyphenylene sulfide-based oil-water separation film and a preparation method thereof, and belongs to the technical field of oil-water separation films. The preparation method comprises the following steps: (1) carrying out hot-pressing treatment on a polyphenylene sulfide non-woven material to form a film, so as to obtain a polyphenylene sulfide film; (2) mixing a metal ion precursor or a metal oxide with a surfactant to obtain ink A; plant polyphenol and a surfactant are mixed, and ink B is obtained; and (3) fixing the polyphenylene sulfide film on an aerosol jet printing platform, carrying out first printing on the surface of the film by using the ink A according to the pattern, and after the printing of the ink A is completed, switching to the ink B to carry out second printing, so that the ink A and the ink B alternately carry out printing to obtain the polyphenylene sulfide-based oil-water separation film. The obtained film is mainly used in the fields of oil-water separation, seawater desalination, sewage treatment and the like, has high oil-water separation efficiency, has acid, alkali and salt resistance, and can still keep high separation efficiency in an extreme environment.

Description

Technical Field

[0001] The invention belongs to the technical field of oil-water separation membranes, and in particular relates to a polyphenylene sulfide-based oil-water separation membrane and a preparation method thereof. Background Art In recent years, with the continuous improvement of the economy, various industries (food processing, textiles and metal casting, etc.) have developed rapidly, resulting in the discharge of a large amount of industrial wastewater containing organic pollutants, and marine oil spills have also occurred one after another, threatening the ecosystem and human safety. In addition, oil and other substances cannot be recycled for a second time, which will also cause economic losses.

[0002] Traditional separation membranes (such as polyvinylidene fluoride PVDF) cannot be used for a long time in extreme environments, such as strong acid (acidic environments such as sulfuric acid and hydrochloric acid), strong alkali (alkaline environments such as sodium hydroxide), high salt (high-concentration sodium chloride solution, etc.), etc., and are easily contaminated by oil droplets, resulting in a shortened lifespan and decreased membrane flux, making it difficult to meet the requirements of rapid separation of oil-water mixtures and long-term stable operation. Therefore, it is of great significance to develop an efficient oil-water separation membrane that can work stably and long-term in extreme environments.

[0003] Li et al. [Li R, Li J, Rao L, et al. Inkjet printing of dopamine followed by UV light irradiation to modify mussel-inspired PVDF membrane for efficient oil-water separation[J]. Journal of Membrane Science, 2021, 619: 118790] used dopamine inkjet printing followed by UV light irradiation to modify mussel-inspired PVDF membrane for efficient oil-water separation. The PVDF membrane was inkjet printed by alternating dopamine ink and alkaline tris(hydroxymethyl)aminomethane (tris) ink. However, the viscosity of inkjet printing is low (1-20cp), the particle size in the ink is small (<100nm), and the grid structure cannot be designed to increase the surface roughness. In addition, the PVDF membrane has poor corrosion resistance and is not conducive to application in strong acid and alkalinity and organic solvents.

[0004] Lv et al. [Lv J, Gong Z, He Z, et al. 3D printing of a mechanically durable superhydrophobic porous membrane for oil–water separation [J]. Journal of Materials Chemistry A, 2017, 5 (24): 12435-12444] used 3D printing to produce a mechanically durable superhydrophobic porous membrane for oil–water separation. A superhydrophobic membrane for oil–water separation with an ordered porous structure was fabricated using polydimethylsiloxane (PDMS) ink filled with hydrophobic nano-silica. However, the speed of 3D printing is low, and the nozzle size is only 0.3~30nm, which is only suitable for flat printing. Chinese patent CN107261856B, published on October 20, 2017, the name of the invention patent is "A polyphenylene sulfide ultrafine fiber oil-water separation membrane and its preparation method". The patent uses a surface spraying method to prepare a polyphenylene sulfide ultrafine fiber oil-water separation membrane, spraying hydrophobic particles on the ultrafine surface of super-hydrophobic polyphenylene sulfide, and then thermally bonding with polyvinylidene fluoride micro-nano powder adhesive to form a three-dimensional network structure of polyphenylene sulfide ultrafine fiber oil-water separation membrane, which can be used for membrane distillation and other membrane separation processes based on hydrophobic membranes. However, its preparation steps are relatively cumbersome, the thermal adhesive has the problem of not being resistant to high temperatures, and the hydrophobic membrane shows a tendency to attract oil droplets to pass through, creating opportunities for oil droplets to contaminate the membrane. Summary of the invention

[0005] The present invention provides a method for preparing a polyphenylene sulfide-based oil-water separation film based on an aerosol jet printing technology. The prepared super-hydrophilic-underwater super-oleophobic polyphenylene sulfide membrane can be used stably for a long time under extreme environments, has a high oil-water separation efficiency, and can effectively avoid oil contamination of materials during the oil-water separation process, thereby reducing environmental pollution from the source, achieving effective recycling of water resources, and extending the service life of the separation membrane. The present invention provides a method for preparing a polyphenylene sulfide-based oil-water separation membrane, comprising the following steps: (1) subjecting the polyphenylene sulfide nonwoven material to a hot pressing treatment to form a film to obtain a polyphenylene sulfide film; (2) mixing a metal ion precursor or a metal oxide with a surfactant to obtain ink A; mixing a plant polyphenol with a surfactant to obtain ink B; (3) Fix the polyphenylene sulfide film on an aerosol jet printing platform, adjust the distance between the nozzle of the aerosol jet printer and the surface of the film, first use ink A to perform a first print on the surface of the film according to a pattern, and after completing the printing of ink A, switch to ink B for the second print. In this way, ink A and ink B are printed alternately to form a dense grid structure on the surface of the film, thereby obtaining a polyphenylene sulfide-based oil-water separation film. Furthermore, step (1) further comprises washing the polyphenylene sulfide nonwoven material with a cleaning solution, rinsing with water, and drying to obtain the washed polyphenylene sulfide nonwoven material, and then subjecting the washed polyphenylene sulfide nonwoven material to a heat pressing treatment to form a film.

[0006] Furthermore, in step (1), the hot pressing temperature is 80-95° C., the hot pressing pressure is 10-20 MPa, and the hot pressing time is 10-20 minutes.

[0007] Furthermore, in step (2), the metal ion precursor includes at least one of copper nitrate or zinc nitrate; the metal oxide includes at least one of titanium dioxide, iron oxide or hydrated iron sulfate; In step (2), the plant polyphenols include at least one of tannic acid, gallic acid, and pyrogallol; In step (2), the surfactant includes at least one of n-propanol and isopropanol. Furthermore, in step (2), in ink A, the mass fraction ratio of the metal ion precursor or metal oxide to the surfactant is 0.2%~2%:10%~20%; in ink B, the mass fraction ratio of the plant polyphenol to the surfactant is 3.0%~10%:10%~20%.

[0008] Furthermore, in step (3), the distance between the nozzle and the membrane surface is adjusted to be between 6 and 8 mm.

[0009] Furthermore, in step (3), the printing speed and carrier gas parameters of the first printing and the second printing are the same; In step (3), the speed of the first printing is 10-20 mm / s; during the first printing, the aerosol flow parameter of carrier gas A is 50-90 sccm, and the sheath flow parameter of carrier gas B is 180-270 sccm; In step (3), the number of layers of the first print is 1 to 3 layers; the number of layers of the second print is 1 to 3 layers.

[0010] Furthermore, in step (3), the pattern is a grid pattern.

[0011] The present invention also provides a polyphenylene sulfide-based oil-water separation membrane prepared by any of the above-mentioned preparation methods.

[0012] The present invention has the following advantages: The present invention proposes a method for preparing a polyphenylene sulfide (PPS) modified film with super hydrophilic-underwater super oleophobic properties. The hydrophilic ink A and ink B are precisely positioned and quantitatively bonded to the polyphenylene sulfide film by aerosol jet printing technology to form a dense grid structure. The interlaced connection between the grids constitutes a rough surface. Whether it is a hydrophobic surface or a hydrophilic surface, increasing the surface roughness can improve the wettability of the material, thereby improving the hydrophilicity of the polyphenylene sulfide film, so that the obtained film has a high oil-water separation efficiency. In addition, the plant polyphenols in ink B and the metal ions or metal oxides in ink A are complexed by coordination bonds to form a metal-polyphenol coating with abundant phenolic hydroxyl groups, which makes it have excellent hydrophilicity. In addition, the metal-polyphenol complex network gives oxygen-rich groups to the membrane surface, and forms a hydration layer by forming hydrogen bonds with water molecules. The hydration layer can prevent oil droplets from directly contacting the membrane surface, thereby enhancing the surface antifouling property of the membrane. In addition, the obtained polyphenylene sulfide membrane is resistant to acid, alkali and salt, and can maintain a high separation efficiency under extreme environments. It can make up for the defects of traditional separation membranes such as poor recyclability, poor corrosion resistance, and being unfavorable for application in strong acidity and alkali and organic solvents. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0014] Figure 1a , Figure 1b They are scanning electron microscope comparison images of the surfaces of the original PPS film and the modified PPS film of Example 1 of the present invention; Figure 2 This is a comparison diagram of the underwater oil state of the original PPS film surface and the modified PPS film surface in Example 1 of the present invention; Figure 3 Schematic diagram of the contact angle between the surface of the modified PPS film and underwater oil in Example 1 of the present invention; Figure 4 This is a schematic diagram of the change in contact angle between the surface of the modified PPS film in Example 1 of the present invention and a water droplet as time goes by. DETAILED DESCRIPTION The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0015] On the one hand, an embodiment of the present invention provides a method for preparing a polyphenylene sulfide-based oil-water separation membrane, comprising the following steps: (1) subjecting the polyphenylene sulfide nonwoven material to a hot pressing treatment to form a film to obtain a polyphenylene sulfide film; (2) mixing a metal ion precursor or a metal oxide with a surfactant to obtain ink A; mixing a plant polyphenol with a surfactant to obtain ink B; (3) Fix the polyphenylene sulfide film on an aerosol jet printing platform, adjust the distance between the nozzle of the aerosol jet printer and the surface of the film, first use ink A to perform a first print on the surface of the film according to a pattern, and after completing the printing of ink A, switch to ink B for the second print. In this way, ink A and ink B are printed alternately to form a dense grid structure on the surface of the film, thereby obtaining a polyphenylene sulfide-based oil-water separation film. The basic principle of aerosol jet printing technology is to atomize the ink into aerosol before printing. It has the advantages of a wide range of ink viscosity, nozzles that are not easily clogged, unlimited printing substrate form (flat or curved), and printing accuracy up to 10μm. It can also achieve the deposition of atomized droplets in specific areas through numerical control. It is a non-contact, low-cost, fast, and environmentally friendly micro-scale additive manufacturing technology based on focused aerosol micro-droplets.

[0016] The method for preparing a polyphenylene sulfide (PPS) modified film with super hydrophilic-underwater super oleophobic properties proposed in the embodiment of the present invention uses aerosol jet printing technology to accurately position and quantitatively bind hydrophilic ink A and ink B to the polyphenylene sulfide film to form a dense grid structure. The interlaced connection between the grids constitutes a rough surface. Whether it is a hydrophobic surface or a hydrophilic surface, increasing the surface roughness can improve the wettability of the material, thereby improving the hydrophilicity of the polyphenylene sulfide film, so that the resulting film has a higher oil-water separation efficiency. In addition, the plant polyphenols in ink B and the metal ions or metal oxides in ink A are complexed by coordination bonds to form a metal-polyphenol coating with rich phenolic hydroxyl groups, which makes it have excellent hydrophilicity, and because the metal-polyphenol complex network gives oxygen-rich groups to the membrane surface, it forms a hydration layer by forming hydrogen bonds with water molecules. The hydration layer can prevent oil droplets from directly contacting the membrane surface, thereby enhancing the surface anti-fouling property of the membrane. In addition, the obtained polyphenylene sulfide membrane is resistant to acid, alkali and salt, and can maintain a high separation efficiency under extreme environments. It can make up for the defects of traditional separation membranes such as poor recyclability, poor corrosion resistance, and being unfavorable for application in strong acidity and alkali and organic solvents.

[0017] In one embodiment of the present invention, step (1) further comprises washing the polyphenylene sulfide (PPS) nonwoven material with a cleaning solution, rinsing with water, and drying to obtain the washed polyphenylene sulfide nonwoven material, and then subjecting the washed polyphenylene sulfide nonwoven material to a heat pressing treatment to form a film.

[0018] In one embodiment of the present invention, in step (1), the cleaning is ultrasonic cleaning. Preferably, in step (1), the power of ultrasonic cleaning is 100-300W, and the time of ultrasonic cleaning is 10-40 minutes. In one embodiment of the present invention, in step (1), the cleaning solution comprises an organic solvent and water; preferably, the organic solvent comprises at least one of acetone and ethanol. More preferably, the volume ratio of the organic solvent to water is 1:1.

[0019] In one embodiment of the present invention, in step (1), the drying is performed in an oven at a drying temperature of 50-80° C. and a drying time of 20-40 minutes.

[0020] In one embodiment of the present invention, in step (1), the temperature of hot pressing is 80-95°C, the pressure of hot pressing is 10-20 MPa, and the time of hot pressing is 10-20 minutes. In the embodiment of the present invention, after hot pressing, the obtained PPS material forms a flat and dense film.

[0021] In one embodiment of the present invention, in step (2), the metal ion precursor includes at least one of copper nitrate or zinc nitrate; and the metal oxide includes at least one of titanium dioxide, iron oxide or hydrated iron sulfate.

[0022] In one embodiment of the present invention, in step (2), the plant polyphenols include at least one of tannic acid (TA), gallic acid (GA), and pyrogallol (PG).

[0023] In one embodiment of the present invention, in step (2), the surfactant includes at least one of n-propanol and isopropanol. In one embodiment of the present invention, in step (2), in ink A, the mass fraction ratio of the metal ion precursor or metal oxide to the surfactant is 0.2%~2%:10%~20%; in ink B, the mass fraction ratio of the plant polyphenol to the surfactant is 3.0%~10%:10%~20%.

[0024] In one embodiment of the present invention, in step (2), the mixing is carried out by stirring. Preferably, the stirring speed is 400-500 rpm and the stirring time is 1-1.5 hours. In one embodiment of the present invention, in step (3), the distance between the nozzle and the membrane surface is adjusted to between 6 and 8 mm.

[0025] In one embodiment of the present invention, in step (3), the printing speed and carrier gas parameters of the first printing and the second printing are the same.

[0026] In one embodiment of the present invention, in step (3), the speed of the first printing is 10-20 mm / s; during the first printing, the aerosol flow parameter of carrier gas A is 50-90 sccm, and the sheath flow parameter of carrier gas B is 180-270 sccm; In one embodiment of the present invention, in step (3), the number of layers of the first printing is 1 to 3 layers; the number of layers of the second printing is 1 to 3 layers.

[0027] In one embodiment of the present invention, in step (3), the pattern is a grid pattern. Compared with spray printing, the aerosol printing used in this application is printed on the basis of a grid pattern. In this way, the hydrophilic ink A and ink B are combined with the polyphenylene sulfide membrane to form a dense grid structure. The interlaced connection between the grids constitutes a rough surface. Whether it is a hydrophobic surface or a hydrophilic surface, increasing the surface roughness can improve the wettability of the material, thereby improving the hydrophilicity of the polyphenylene sulfide membrane, so that the obtained film has a higher oil-water separation efficiency.

[0028] In one embodiment of the present invention, in step (3), the printing environment temperature is room temperature, specifically 10-25°C.

[0029] On the other hand, the embodiments of the present invention also propose a polyphenylene sulfide-based oil-water separation film prepared by any of the above methods. The super-hydrophilic-underwater super-oleophobic surface membrane is also called a "water removal type" material. It can selectively separate water from the oil-water mixture and has extremely strong oleophobicity, which can ensure that the surface of the membrane material is not contaminated and adhered by oil. The super-hydrophilic-underwater super-oleophobic polyphenylene sulfide-based oil-water separation film obtained by the present invention has a high oil-water separation efficiency, and the special wettability of the membrane surface makes it difficult for oil droplets to adhere, thereby significantly reducing the pollution of the membrane material by oil, effectively maintaining a high separation flux, and extending the service life of the membrane. It has excellent anti-fouling performance and can be quickly separated and operated stably for a long time. It is mainly used in the fields of oil-water separation, seawater desalination, and sewage treatment.

[0030] Example 1 A method for preparing polyphenylene sulfide-based oil-water separation film based on aerosol jet printing technology (1) Cleaning of PPS nonwoven materials: Select PPS nonwoven materials of appropriate specifications and place them in a cleaning solution. The cleaning solution is an organic solvent ethanol and deionized water (volume ratio 1:1). Place them in an ultrasonic cleaning device for cleaning at room temperature. The ultrasonic power is 180W and the cleaning time is 22 minutes. After cleaning, rinse with a large amount of deionized water to remove impurities and oil stains on the surface, then dry them in an oven at 60°C for 28 minutes and set aside; (2) PPS nonwoven material hot pressing film: The cleaned and dried PPS nonwoven material is hot pressed in a hot press. The hot pressing temperature is set at 87°C, the pressure is 15 MPa, and the hot pressing time is 14 minutes, so that the PPS material forms a flat and dense film to obtain a PPS film; (3) Printing ink configuration Printing ink A preparation: 0.47% hydrated ferric sulfate and 17% n-propanol were mixed by mass fraction, and stirred on a magnetic stirrer at 400 rpm for 1 hour to ensure that the solution was evenly mixed, thereby obtaining printing ink A; Printing ink B preparation: 3.8% tannic acid and 17% n-propanol were mixed according to the mass fraction, and stirred on a magnetic stirrer at a speed of 400 rpm for 1 hour until the plant polyphenols were completely dissolved to obtain printing ink B; (4) Aerosol jet printing: Fix the hot-pressed PPS film on the aerosol jet printing platform, adjust the distance between the nozzle and the film surface to 7 mm, use aerosol jet printing technology, first use printing ink A to print on the PPS film, set the printing speed to 15 mm / s, the number of printing layers to 1 layer, the parameters of carrier gas A to 60 sccm, and the parameters of carrier gas B to 180 sccm; print according to the preset grid pattern. After completing the printing of printing ink A, switch to printing ink B and print at the same printing speed and carrier gas parameters, with 1 printing layer. The two inks are printed alternately to form a dense grid structure on the PPS film, and finally a super-hydrophilic-underwater super-oleophobic modified PPS film is obtained. During the printing process, the temperature of the printing environment is kept at room temperature.

[0031] Example 2 A method for preparing polyphenylene sulfide-based oil-water separation film based on aerosol jet printing technology (1) Cleaning of PPS nonwoven materials: Select PPS nonwoven materials of appropriate specifications and place them in a cleaning solution. The cleaning solution is an organic solvent ethanol and deionized water (volume ratio 1:1). Place them in an ultrasonic cleaning device for cleaning at room temperature. The ultrasonic power is 100W and the cleaning time is 10 minutes. After cleaning, rinse with a large amount of deionized water to remove impurities and oil stains on the surface, then dry them in an oven at 50°C for 20 minutes and set aside; (2) Hot pressing of PPS nonwoven material into film: The cleaned and dried PPS nonwoven material is placed in a hot press for hot pressing. The hot pressing temperature is set at 80°C, the pressure is 10 MPa, and the hot pressing time is 10 minutes, so that the PPS material forms a flat and dense film to obtain a PPS film; (3) Printing ink configuration Printing ink A: 0.2% hydrated ferric sulfate and 10% n-propanol were mixed by mass fraction. The mixture was stirred on a magnetic stirrer at 400 rpm for 1 hour to ensure that the solution was evenly mixed to form printing ink A; Printing ink B: 3.0% tannic acid and 10% n-propanol were mixed by mass fraction. The mixture was stirred on a magnetic stirrer at 400 rpm for 1 hour until the plant polyphenols were completely dissolved, thereby obtaining printing ink B; (4) Aerosol jet printing: Fix the hot-pressed PPS film on the aerosol jet printing platform and adjust the distance between the nozzle and the film surface to 6 mm. Use aerosol jet printing technology to first print on the PPS film using printing ink A. The printing speed is set to 10 mm / s, the number of printing layers is 3, the parameters of carrier gas A are 50 sccm, and the parameters of carrier gas B are 200 sccm; print according to the preset grid pattern.

[0032] After printing ink A, switch to printing ink B and print at the same printing speed and carrier gas parameters, with 1 layer. The two inks are printed alternately to form a dense grid structure on the PPS membrane, and finally a super-hydrophilic-underwater super-oleophobic modified PPS membrane is obtained. During the printing process, the temperature of the printing environment is kept at room temperature.

[0033] Example 3 A method for preparing polyphenylene sulfide-based oil-water separation film based on aerosol jet printing technology (1) Cleaning of PPS nonwoven materials: Select PPS nonwoven materials of appropriate specifications and place them in a cleaning solution. The cleaning solution is an organic solvent ethanol and deionized water (volume ratio 1:1). Place them in an ultrasonic cleaning device for cleaning at room temperature. The ultrasonic power is 140W and the cleaning time is 18 minutes. After cleaning, rinse with a large amount of deionized water to remove impurities and oil stains on the surface, then dry them in an oven at 56°C for 22 minutes and set aside; (2) PPS nonwoven material hot pressing film: The cleaned and dried PPS nonwoven material is placed in a hot press for hot pressing. The hot pressing temperature is set at 84°C, the pressure is 12 MPa, and the hot pressing time is 12 minutes, so that the PPS material forms a flat and dense film to obtain a PPS film; (3) Printing ink configuration Printing ink A: 0.3% hydrated ferric sulfate and 14% n-propanol were mixed by mass fraction. The mixture was stirred on a magnetic stirrer at 400 rpm for 1 hour to ensure that the solution was evenly mixed to form printing ink A; Printing ink B: 3.2% tannic acid and 14% n-propanol were mixed by mass fraction. The mixture was stirred on a magnetic stirrer at 400 rpm for 1 hour until the plant polyphenols were completely dissolved, thereby obtaining printing ink B; (4) Aerosol jet printing: Fix the hot-pressed PPS film on the aerosol jet printing platform and adjust the distance between the nozzle and the film surface to 6 mm. Use aerosol jet printing technology to first print on the PPS film using printing ink A. The printing speed is set to 12 mm / s, the number of printing layers is 2, the parameters of carrier gas A are 60 sccm, and the parameters of carrier gas B are 240 sccm; print according to the preset grid pattern.

[0034] After printing ink A, switch to printing ink B and print at the same printing speed and carrier gas parameters, with 1 layer. The two inks are printed alternately to form a dense grid structure on the PPS membrane, and finally a super-hydrophilic-underwater super-oleophobic modified PPS membrane is obtained. During the printing process, the temperature of the printing environment is kept at room temperature.

[0035] Example 4 A method for preparing polyphenylene sulfide-based oil-water separation film based on aerosol jet printing technology (1) Cleaning of PPS nonwoven materials: Select PPS nonwoven materials of appropriate specifications and place them in a cleaning solution. The cleaning solution is an organic solvent ethanol and deionized water (volume ratio 1:1). Place them in an ultrasonic cleaning device for cleaning at room temperature. The ultrasonic power is 230W and the cleaning time is 28 minutes. After cleaning, rinse with a large amount of deionized water to remove impurities and oil stains on the surface, and then dry them in an oven at 68°C for 33 minutes for use; (2) PPS nonwoven material hot pressing film: The cleaned and dried PPS nonwoven material is placed in a hot press for hot pressing. The hot pressing temperature is set at 87°C, the pressure is 19 MPa, and the hot pressing time is 16 minutes, so that the PPS material forms a flat and dense film to obtain a PPS film; (3) Printing ink configuration Printing ink A: 1.2% hydrated ferric sulfate and 17% isopropanol were mixed by mass fraction. Stirred on a magnetic stirrer at 450 rpm for 1.2 hours to ensure that the solution was evenly mixed to form printing ink A; Printing ink B: 6.5% tannic acid and 17% isopropanol were mixed by mass fraction. The mixture was stirred on a magnetic stirrer at 450 rpm for 1.2 hours until the plant polyphenols were completely dissolved, thereby obtaining printing ink B; (4) Aerosol jet printing: The hot-pressed PPS film was fixed on the aerosol jet printing platform, and the distance between the nozzle and the film surface was adjusted to 7 mm. Using aerosol jet printing technology, first use printing ink A to print on the PPS film. The printing speed was set to 15 mm / s, the number of printing layers was 1 layer, the parameters of carrier gas A were 75 sccm, and the parameters of carrier gas B were 225 sccm; printing was performed according to the preset grid pattern.

[0036] After printing ink A, switch to ink B and print at the same printing speed and carrier gas parameters, with 2 layers. The two inks are printed alternately to form a dense grid structure on the PPS membrane, and finally a super-hydrophilic-underwater super-oleophobic modified PPS membrane is obtained. During the printing process, the temperature of the printing environment is kept at room temperature.

[0037] Example 5 A method for preparing polyphenylene sulfide-based oil-water separation film based on aerosol jet printing technology (1) Cleaning of PPS nonwoven materials: Select PPS nonwoven materials of appropriate specifications and place them in a cleaning solution. The cleaning solution is an organic solvent ethanol and deionized water (volume ratio 1:1). Place them in an ultrasonic cleaning device for cleaning at room temperature. The ultrasonic power is 270W and the cleaning time is 35 minutes. After cleaning, rinse with a large amount of deionized water to remove impurities and oil stains on the surface, then dry them in an oven at 74°C for 36 minutes for use; (2) Hot pressing of PPS nonwoven material into film: The cleaned and dried PPS nonwoven material is placed in a hot press for hot pressing. The hot pressing temperature is set at 92°C, the pressure is 19 MPa, and the hot pressing time is 18 minutes, so that the PPS material forms a flat and dense film to obtain a PPS film; (3) Printing ink configuration Printing ink A: 1.8% hydrated ferric sulfate and 19% isopropanol were mixed by weight. The mixture was stirred on a magnetic stirrer at 450 rpm for 1.2 hours to ensure that the solution was evenly mixed to form printing ink A.

[0038] Printing ink B: 8.3% pyrogallol and 19% isopropanol were mixed by mass fraction and stirred on a magnetic stirrer at 450 rpm for 1.2 hours until the plant polyphenols were completely dissolved, thereby obtaining printing ink B.

[0039] (4) Aerosol jet printing: The hot-pressed PPS film was fixed on the aerosol jet printing platform, and the distance between the nozzle and the film surface was adjusted to 8 mm. Using aerosol jet printing technology, first use printing ink A to print on the PPS film. The printing speed was set to 18 mm / s, the number of printing layers was 2 layers, the parameters of carrier gas A were 80 sccm, and the parameters of carrier gas B were 240 sccm; printing was performed according to the preset grid pattern. After printing ink A, switch to ink B and print at the same printing speed and carrier gas parameters, with 3 layers. The two inks are printed alternately to form a dense grid structure on the PPS membrane, and finally a super-hydrophilic-underwater super-oleophobic modified PPS membrane is obtained. During the printing process, the temperature of the printing environment is kept at room temperature. Example 6 A method for preparing polyphenylene sulfide-based oil-water separation film based on aerosol jet printing technology (1) Cleaning of PPS nonwoven materials: Select PPS nonwoven materials of appropriate specifications and place them in a cleaning solution. The cleaning solution is an organic solvent ethanol and deionized water (volume ratio 1:1). Place them in an ultrasonic cleaning device for cleaning at room temperature. The ultrasonic power is 300W and the cleaning time is 40 minutes. After cleaning, rinse with a large amount of deionized water to remove impurities and oil stains on the surface, then dry them in an oven at 80°C for 40 minutes for use; (2) PPS nonwoven material hot pressing film: The cleaned and dried PPS nonwoven material is placed in a hot press for hot pressing. The hot pressing temperature is set at 95°C, the pressure is 20 MPa, and the hot pressing time is 20 minutes, so that the PPS material forms a flat and dense film to obtain a PPS film; (3) Printing ink configuration Printing ink A: Calculate by mass fraction by mixing 2% hydrated ferric sulfate and 20% isopropanol. Stir on a magnetic stirrer at 500 rpm for 1.5 hours to ensure that the solution is evenly mixed to form printing ink A; Printing ink B: 10% pyrogallol and 20% isopropanol were mixed by mass fraction. The mixture was stirred on a magnetic stirrer at a speed of 500 rpm for 1.5 hours until the plant polyphenols were completely dissolved, thereby obtaining printing ink B; (4) Aerosol jet printing: Fix the hot-pressed PPS film on the aerosol jet printing platform and adjust the distance between the nozzle and the film surface to 8 mm. Use aerosol jet printing technology to first print on the PPS film using printing ink A. The printing speed is set to 20 mm / s, the number of printing layers is 3, the parameters of carrier gas A are 90 sccm, and the parameters of carrier gas B are 270 sccm; print according to the preset grid pattern.

[0040] After printing ink A, switch to printing ink B and print at the same printing speed and carrier gas parameters, with 3 layers. The two inks are printed alternately to form a dense grid structure on the PPS film, and finally a super-hydrophilic-underwater super-oleophobic modified PPS film is obtained. During the printing process, the temperature of the printing environment is kept at room temperature. Test Example 1 (1) Surface morphology of modified PPS film and original PPS film in test example 1 The surface morphology of the modified film obtained in Example 1 and the original PPS film were tested by SEM, and the results are shown in FIG1 .

[0041] Figure 1a This is a scanning electron microscope image of the original PPS film. It can be seen from the image that the surface of the PPS fiber is smooth, and the fibers are intertwined to form a three-dimensional network structure or there are many gaps. Figure 1b The SEM image of the modified PPS film shows that tannic acid (TA) and Fe 3+ After solution alternating printing, the TA–Fe(III) complex penetrated into the fiber structure of the PPS film, thereby enhancing the hydrophilicity and antifouling properties of the membrane.

[0042] (2) Test the contact angles of the modified PPS film and the original PPS film in Example 1 with water and with underwater oil The specific method for testing the contact angle includes: fixing the modified PPS film on a glass slide with a clip, immersing it completely in water, dropping 5 μL of dichloromethane on the surface of the modified PPS film using a syringe, and recording the image of the droplet with a high-resolution camera. Figure 2 The following is a comparison of the underwater oil state of the surface (dark rectangular area) of the original PPS film and the modified PPS film obtained after printing according to the method of Example 1. Figure 2 It can be obtained that the dark rectangular area is the super hydrophilic-underwater super oleophobic PPS film obtained in Example 1, and the rest is the original PPS film. The surface of the modified PPS film has underwater oleophobicity, and the oil droplets appear in the shape of oil beads, while the surface of the original PPS film has oleophilicity, and the oil droplets have spread onto the film. Figure 3 Schematic diagram of the contact angle between the surface of the modified PPS film obtained in Example 1 and underwater oil. The contact angles of the surfaces of the modified PPS films of Examples 2 to 6 with water and the contact angles of the surfaces of the modified PPS films with underwater oil were tested in the same manner as above. The specific results are shown in Table 1. The contact angle between the surface of the modified PPS film obtained in Example 1 and the water droplet was further tested over time. The specific method included: using a syringe to drop 5 μL of water on the surface of the modified PPS film, and taking an image of the droplet with a high-resolution camera. The results are shown in FIG. Figure 4 .from Figure 4 It can be seen that the water droplet gradually infiltrates the surface of the PPS film with the extension of time, the contact angle gradually decreases, and finally the contact angle is <1°.

[0043] (3) Testing the oil-water separation performance of the superhydrophilic-underwater superoleophobic modified PPS film 10 ml of n-hexane and 10 ml of water were mixed to form an oil-water mixture. The modified PPS films obtained in Examples 1 to 6 were sandwiched between two filter cups placed up and down with their bottoms facing each other. After the modified PPS films were soaked with water, the oil-water mixture was poured into the filter cups placed above. The oil-water separation test was performed, and the mass of water before and after separation was recorded. Oil-water separation efficiency formula: η=M t ÷M 0 ×100%. Among them, M 0 is the mass of initial water before separation, M t is the mass of water after separation. The results are shown in Table 1. (4) Testing the chemical stability of polyphenylene sulfide membranes under different environments The modified polyphenylene sulfide membranes obtained in Examples 1 to 6 were respectively heated at H 2 SO 4 After immersing in a strong acid, strong alkali and high salt environment of (1mol / L), NaOH (1mol / L) and NaCl (1mol / L) for 24h, the experiment of separating the mixture of n-hexane and water was carried out, and its oil-water separation efficiency was tested. The results are shown in Table 1.

[0044] Table 1

[0045] As can be seen from Table 1, the super hydrophilic-underwater super oleophobic polyphenylene sulfide membrane (PPS) prepared by the present invention has a water contact angle in the air of <1°, an underwater oil contact angle of >150°, an oil-water separation efficiency of more than 96%, a good separation effect for n-hexane, and exhibits high separation efficiency, separation flux and strong chemical stability under extreme environments (acidic / alkaline solutions, salts and high temperature environments).

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a polyphenylene sulfide-based oil-water separation membrane, characterized in that: The steps include: (1) subjecting the polyphenylene sulfide nonwoven material to a hot pressing treatment to form a film to obtain a polyphenylene sulfide film; (2) mixing a metal ion precursor or a metal oxide with a surfactant to obtain ink A; The plant polyphenols and the surfactant are mixed to obtain ink B; (3) Fix the polyphenylene sulfide film on an aerosol jet printing platform, adjust the distance between the nozzle of the aerosol jet printer and the surface of the film, first use ink A to perform a first print on the surface of the film according to a pattern, and after completing the printing of ink A, switch to ink B for the second print. In this way, ink A and ink B are printed alternately to form a dense grid structure on the surface of the film, thereby obtaining a polyphenylene sulfide-based oil-water separation film.

2. The preparation method according to claim 1, characterized in that: Step (1) also includes washing the polyphenylene sulfide nonwoven material with a cleaning solution, rinsing with water, and drying to obtain the washed polyphenylene sulfide nonwoven material, and then performing a heat pressing process to form a film.

3. The preparation method according to claim 1, characterized in that: In step (1), the hot pressing temperature is 80-95° C., the hot pressing pressure is 10-20 MPa, and the hot pressing time is 10-20 minutes.

4. The preparation method according to claim 1, characterized in that: In step (2), the metal ion precursor includes at least one of copper nitrate or zinc nitrate; the metal oxide includes at least one of titanium dioxide, iron oxide or hydrated iron sulfate; In step (2), the plant polyphenols include at least one of tannic acid, gallic acid, and pyrogallol; In step (2), the surfactant includes at least one of n-propanol and isopropanol.

5. The preparation method according to claim 1, characterized in that: In step (2), in ink A, the mass fraction ratio of metal ion precursor or metal oxide to surfactant is 0.2%~2%:10%~20%; in ink B, the mass fraction ratio of plant polyphenol to surfactant is 3.0%~10%:10%~20%.

6. The preparation method according to claim 1, characterized in that: In step (3), the distance between the nozzle and the membrane surface is adjusted to between 6 and 8 mm.

7. The preparation method according to claim 1, characterized in that: In step (3), the printing speed and carrier gas parameters of the first printing and the second printing are the same; In step (3), the speed of the first printing is 10-20 mm / s; during the first printing, the aerosol flow parameter of carrier gas A is 50-90 sccm, and the sheath flow parameter of carrier gas B is 180-270 sccm; In step (3), the number of layers of the first print is 1 to 3 layers; the number of layers of the second print is 1 to 3 layers.

8. The preparation method according to claim 1, characterized in that: In step (3), the pattern is a grid pattern.

9. The polyphenylene sulfide-based oil-water separation membrane prepared by the preparation method according to any one of claims 1 to 8.

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