High-water-flux polyketone separation membrane based on hydrogen bond regulation and preparation method thereof

Abstract

The invention discloses a preparation method of a high-water-flux polyketone separation membrane based on hydrogen bond regulation and control, and belongs to the field of organic separation membranes. The preparation method of the high-water-flux polyketone separation membrane based on hydrogen bond regulation and control comprises the following steps: mixing polyketone, a hydrogen bond donor additive and a diluent, heating, stirring, and carrying out vacuum defoaming to obtain a membrane casting solution; scraping the membrane casting solution on a non-woven fabric supporting layer or extruding the membrane casting solution through a spinning nozzle mold to obtain a primary membrane; putting the primary membrane into cooling bath pure water, and curing to obtain a polyketone separation membrane; soaking the polyketone separation membrane in pure water, then soaking the polyketone separation membrane in a glycerol aqueous solution, and drying to obtain a polyketone dry membrane; the hydrogen bond component range of the hydrogen bond donor additive is 18-26 (MPa) 1 / 2. Compared with the membrane without the hydrogen bond donor additive, the membrane flux is obviously improved, the porosity of the surface of the polyketone separation membrane is increased, and the separation efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the field of organic separation membranes, and particularly relates to a high water flux polyketone separation membrane regulated by hydrogen bonds and a preparation method thereof. Background Art

[0002] POK (aliphatic polyketone, hereinafter referred to as polyketone) is a crystalline and thermoplastic engineering material with a linear structure formed by alternating copolymerization of carbon monoxide with ethylene and propylene. This polymer is a green environmental protection material using carbon monoxide, one of the atmospheric pollutants, as a raw material. Polyketone materials are engineering plastics with a main chain composed entirely of carbon chains, and have good hydrophilicity, high heat distortion temperature, high mechanical properties, and chemical solvent resistance.

[0003] Thermally induced phase separation enhances the selectivity of diluents. (Tang Y H, Liu J, Zhou B, et al. Advanced Membranes, Volume 2, 2022, 100033) analyzed that the interaction between diluents and polymers (Hansen dispersion, polarity, and hydrogen bond components) affects the phase separation process of the casting solution, resulting in the formation of liquid-liquid phase separation or liquid-solid phase separation. Since polyketone will undergo oxidative degradation at high temperatures, the stirring and dissolution temperature of the casting solution in its thermally induced phase separation method cannot exceed 200 °C for a long time. Therefore, the diluent needs to have good solubility for polyketone polymers at relatively low temperatures. And (Xiang S, Zhang P, Rajabzadeh S, et al. Journal of Membrane Science, Volume 677, 5 July 2023, 121639) mentioned that if the solubility of the diluent and the polymer is good, it will be difficult to form liquid-liquid phase separation during the phase separation process, resulting in poor connectivity of the pore structure of the polyketone separation membrane, low surface porosity, and small flux.

[0004] Therefore, a high water flux polyketone separation membrane regulated by hydrogen bonds and a preparation method thereof are proposed. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a high water flux polyketone separation membrane regulated by hydrogen bonds and a preparation method thereof, which solves the problems in the prior art.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A preparation method of a polyketone separation membrane regulated by hydrogen bonds, comprising the following steps:

[0008] Mix polyketone, a hydrogen bond donor additive, and a diluent, heat and stir, and then perform vacuum degassing to obtain a casting solution;

[0009] The casting solution is scraped onto a non-woven support layer or extruded through a spinneret die to obtain a nascent membrane;

[0010] The nascent membrane is placed in pure water in a cooling bath and then cured to obtain a polyketone separation membrane;

[0011] The polyketone separation membrane is soaked in pure water, then soaked in an aqueous glycerol solution, and dried to obtain a polyketone dry membrane;

[0012] The hydrogen bond component range of the hydrogen bond donor additive is 18 - 26 (MPa) 1 / 2 。

[0013] Furthermore, the mass ratio of the polyketone, the hydrogen bond donor additive, and the diluent is (18 - 23):(2 - 5):(73 - 82).

[0014] Furthermore, the hydrogen bond donor additive is: ethylene glycol, gallic acid, propylene glycol, catechol, or formamide.

[0015] Furthermore, the diluent is DMSO, NMP, or DMI.

[0016] Furthermore, the film-forming morphology of the casting solution is: flat membrane or hollow fiber membrane.

[0017] Furthermore, the mixing and heating temperature of the polyketone, the hydrogen bond donor additive, and the diluent is 120°C - 160°C.

[0018] Furthermore, the temperature of the cooling bath is 40°C - 60°C.

[0019] Furthermore, the mass fraction of the aqueous glycerol solution is 20%.

[0020] The polyketone separation membrane based on hydrogen bond regulation is prepared by using the preparation method of the polyketone separation membrane based on hydrogen bond regulation as described above.

[0021] The application of the above polyketone separation membrane based on hydrogen bond regulation in the separation and purification of organic substances, filtration and sterilization, and wastewater treatment.

[0022] Advantages of the present invention:

[0023] 1. The present invention adds a hydrogen bond donor additive within a certain hydrogen bond component range, and the membrane flux is significantly improved compared to the membrane without the addition of the hydrogen bond donor additive. The porosity on the surface of the polyketone separation membrane is increased, and the separation efficiency is improved.

[0024] 2. In the present invention, the dissolution effect of the casting solution is good, the dissolution temperature is low, and the phenomenon of oxidation and yellowing of the polyketone membrane is significantly reduced.

[0025] 3. Both the diluent and the hydrogen bond donor additive used in the present invention are water-soluble. Water is selected as the coolant and extractant, which reduces energy consumption, simplifies the process steps, ensures the safety of the production process, and has less impact on environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0027] Figure 1 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Comparative Example 1 of the present invention;

[0028] Figure 2 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Comparative Example 2 of the present invention;

[0029] Figure 3 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Example 1 of the present invention;

[0030] Figure 4 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Example 2 of the present invention;

[0031] Figure 5 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Comparative Example 3 of the present invention;

[0032] Figure 6 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Comparative Example 4 of the present invention;

[0033] Figure 7 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Example 3 of the present invention;

[0034] Figure 8 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Comparative Example 5 of the present invention;

[0035] Figure 9 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Comparative Example 6 of the present invention;

[0036] Figure 10 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Example 4 of the present invention;

[0037] Figure 11 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Example 5 of the present invention;

[0038] Figure 12 Scanning electron micrograph of the surface of the aliphatic polyketone separation membrane of Comparative Example 7 of the present invention. Detailed implementation mode

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0040] A preparation method of a high water flux polyketone separation membrane based on hydrogen bond regulation includes the following steps:

[0041] S1. Mix polyketone (POK), a hydrogen bond donor additive, and a diluent, heat to 120°C to 160°C, fully stir until a homogeneous solution is obtained, and then perform vacuum degassing on it to obtain a casting solution for film formation;

[0042] S2. Scrape the casting solution on a non-woven fabric support layer or extrude it through a spinneret die to obtain a primary film;

[0043] S3. Place the primary film in pure water in a cooling bath, set the cooling bath temperature to 40°C to 60°C, and cure it after soaking for more than 1 h to obtain a polyketone separation membrane;

[0044] S4. Place the cured polyketone separation membrane in pure water for soaking, then soak it in a 20 wt% glycerol aqueous solution, and dry or bake it to obtain a polyketone dry film.

[0045] Among them, in S1, the casting solution for film formation includes the following components in parts by weight: 18 to 23 parts of polyketone, 2 to 5 parts of hydrogen bond donor additive, and 73 to 82 parts of diluent.

[0046] The polyketone is polymerized from carbon monoxide and olefins (ethylene, propylene).

[0047] The hydrogen bond donor additive is: ethylene glycol, gallic acid, propylene glycol, catechol or formamide, and the hydrogen bond component range of the hydrogen bond donor additive is 18 to 26 (MPa) 1 / 2 .

[0048] The diluent is DMSO, NMP or DMI.

[0049] The film-forming morphology of the casting solution includes flat membranes, hollow fiber membranes, etc.

[0050] Next, the technical solutions of the present invention will be described in detail through the following examples and comparative examples (the parts in the examples and comparative examples are all parts by mass).

[0051] Example 1

[0052] S1. Add 20 parts of POK, 5 parts of formamide, and 75 parts of DMSO into a container and mix them. Heat the mixture to 120 °C. After fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution.

[0053] S2. Use pure water as the core liquid (at a temperature of 60 °C). Extrude the prepared casting solution and the core liquid through a spinneret to prepare a hollow fiber membrane embryo.

[0054] S3. Directly place the prepared hollow fiber membrane embryo into a pure water cooling bath. Control the water temperature of the cooling bath at 60 °C and the curing time at 1 h.

[0055] S4. Immerse the cured membrane in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK hollow fiber membrane. Its scanning electron micrograph is as shown in Figure 3 shown.

[0056] Example 2

[0057] S1. Add 20 parts of POK, 3 parts of catechol, and 77 parts of DMSO into a container and mix them. Heat the mixture to 120 °C. After fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution.

[0058] S2. Prepare a flat membrane with the casting solution on an automatic film casting machine.

[0059] S3. Immediately immerse the flat membrane in a pure water cooling bath. Control the water temperature of the cooling bath at 60 °C and the curing time at 1 h.

[0060] S4. Immerse the cured membrane in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat membrane. Its scanning electron micrograph is as shown in Figure 4 shown.

[0061] Example 3

[0062] S1. Add 18 parts of POK, 3 parts of ethylene glycol, and 79 parts of NMP into a container and mix them. Heat the mixture to 140 °C. After fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution.

[0063] S2. Prepare a flat membrane with the casting solution on an automatic film casting machine.

[0064] S3. Immediately immerse the flat membrane in a pure water cooling bath. Control the water temperature of the cooling bath at 50 °C and the curing time at 1 h.

[0065] S4. Immerse the cured membrane in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat membrane. Its scanning electron micrograph is as shown in Figure 7 shown.

[0066] Example 4

[0067] S1. Add 23 parts of POK, 4 parts of propylene glycol, and 73 parts of DMI into a container and mix them. Heat the mixture to 160 °C. After fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution.

[0068] S2. Prepare a flat film from the casting solution on an automatic film scraping machine.

[0069] S3. Immediately immerse the flat film in a pure water cooling bath. Control the water temperature of the cooling bath at 40 °C and the curing time at 1 h.

[0070] S4. Immerse the cured film in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat film. Its scanning electron micrograph is as shown in Figure 10 shown.

[0071] Example 5

[0072] S1. Add 23 parts of POK, 2 parts of gallic acid, and 75 parts of DMI into a container and mix them. Heat the mixture to 160 °C. After fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution.

[0073] S2. Prepare a flat film from the casting solution on an automatic film scraping machine.

[0074] S3. Immediately immerse the flat film in a pure water cooling bath. Control the water temperature of the cooling bath at 40 °C and the curing time at 1 h.

[0075] S4. Immerse the cured film in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat film. Its scanning electron micrograph is as shown in Figure 11 shown.

[0076] Comparative Example 1

[0077] S1. Add 20 parts of POK and 80 parts of DMSO into a container and mix them. Heat the mixture to 120 °C. After fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution.

[0078] S2. Prepare a flat film from the casting solution on an automatic film scraping machine.

[0079] S3. Immediately immerse the flat film in a pure water cooling bath. Control the water temperature of the cooling bath at 60 °C and the curing time at 1 h.

[0080] S4. Immerse the cured film in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat film. Its scanning electron micrograph is as shown in Figure 1 shown.

[0081] Comparative Example 2

[0082] S1. Add 20 parts of POK, 5 parts of dipropylene glycol butyl ether, and 75 parts of DMSO into a container and mix them. Heat to 120 °C. After fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution;

[0083] S2. Prepare a flat film from the casting solution on an automatic film casting machine;

[0084] S3. Immediately immerse the flat film in a pure water cooling bath. Control the water temperature of the cooling bath at 60 °C and the curing time at 1 h;

[0085] S4. Immerse the cured film in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat film. Its scanning electron micrograph is as shown in Figure 2 shown.

[0086] Comparative Example 3

[0087] S1. Add 18 parts of POK and 82 parts of NMP into a container and mix them. Heat to 140 °C. After fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution;

[0088] S2. Prepare a flat film from the casting solution on an automatic film casting machine;

[0089] S3. Immediately immerse the flat film in a pure water cooling bath. Control the water temperature of the cooling bath at 50 °C and the curing time at 1 h;

[0090] S4. Immerse the cured film in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat film. Its scanning electron micrograph is as shown in Figure 5 shown.

[0091] Comparative Example 4

[0092] S1. Add 18 parts of POK, 5 parts of N-methylformamide, and 77 parts of NMP into a container and mix them. Heat to 140 °C. After fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution;

[0093] S2. Prepare a flat film from the casting solution on an automatic film casting machine;

[0094] S3. Immediately immerse the flat film in a pure water cooling bath. Control the water temperature of the cooling bath at 55 °C and the curing time at 1 h;

[0095] S4. Immerse the cured film in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat film. Its scanning electron micrograph is as shown in Figure 6 shown.

[0096] Comparative Example 5

[0097] S1. Add 18 parts of POK, 2 parts of L - malic acid, and 80 parts of NMP into a container, mix them, heat to 140 °C, and after fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution;

[0098] S2. Prepare a flat film from the casting solution on an automatic film - scraping machine;

[0099] S3. Immediately immerse the flat film in a pure - water cooling bath, control the water temperature of the cooling bath at 50 °C, and the curing time is 1 h;

[0100] S4. Immerse the cured film in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat film, and its scanning electron micrograph is as shown in Figure 8 shown.

[0101] Comparative Example 6

[0102] S1. Add 23 parts of POK and 77 parts of DMI into a container, mix them, heat to 160 °C, and after fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution;

[0103] S2. Prepare a flat film from the casting solution on an automatic film - scraping machine;

[0104] S3. Immediately immerse the flat film in a pure - water cooling bath, control the water temperature of the cooling bath at 40 °C, and the curing time is 1 h;

[0105] S4. Immerse the cured film in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat film, and its scanning electron micrograph is as shown in Figure 9 shown.

[0106] Comparative Example 7

[0107] S1. Add 23 parts of POK, 2 parts of glycerol, and 75 parts of DMI into a container, mix them, heat to 160 °C, and after fully dispersing and homogenizing, evacuate to remove air bubbles to obtain a casting solution;

[0108] S2. Prepare a flat film from the casting solution on an automatic film - scraping machine;

[0109] S3. Immediately immerse the flat film in a pure - water cooling bath, control the water temperature of the cooling bath at 40 °C, and the curing time is 1 h;

[0110] S4. Immerse the cured film in pure water at 30 °C for 3 h, then immerse it in a 20 wt% glycerol aqueous solution for 24 h, and dry it in an oven at 40 °C to obtain a dry POK flat film, and its scanning electron micrograph is as shown in Figure 12 shown.

[0111] Experimental test

[0112] The polyketone separation membranes prepared in the above examples and comparative examples were tested and analyzed: The pure water fluxes of the polyketone separation membranes prepared in all the above examples and comparative examples were measured at a temperature of 25°C and an operating pressure of 0.1 MPa. The results are shown in Table 1 below:

[0113] Table 1 Pure water flux data of polyketone separation membranes

[0114]

[0115] As can be seen from Table 1, in the examples, the hydrogen bond component ranges from 18 to 26 (MPa) 1 / 2 of the hydrogen bond donor additive can make the flux of the polyketone separation membrane much higher than that of the polyketone separation membrane without the hydrogen bond donor additive in the comparative example. When the hydrogen bond component exceeds this range, the flux change is not obvious or the flux decreases significantly.

[0116] From Figures 1 - 12 the electron microscope images, it can be seen that at the same magnification, in the examples, the hydrogen bond component ranges from 18 to 26 (MPa) 1 / 2 of the hydrogen bond donor additive can make the number of surface pores of the polyketone separation membrane more than that of the polyketone separation membrane without the hydrogen bond donor additive in the comparative example, and the porosity increases. When the hydrogen bond component exceeds this range, there is no obvious change in the number of pores on the surface of the polyketone separation membrane, or the number of pores decreases and the porosity decreases.

[0117] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0118] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A method for preparing a polyketone separation membrane based on hydrogen bond regulation, characterized in that: The following steps are involved: The polyketone, hydrogen bond donor additive and diluent are mixed, heated and stirred, and then vacuum degassing is performed to obtain a film casting solution; The casting solution is scraped onto a non-woven fabric support layer or extruded through a spinneret die to obtain a primary membrane; The primary membrane is placed in a cooling bath of pure water and then solidified to obtain a polyketone separation membrane; The polyketone separation membrane is immersed in pure water, then immersed in a glycerol aqueous solution, and dried to obtain a polyketone dry membrane; The hydrogen bond component of the hydrogen bond donor additive is in the range of 18 to 26 (MPa) 1 / 2 .

2. The method for preparing a polyketone separation membrane based on hydrogen bond regulation according to claim 1, characterized in that: The mass ratio of the polyketone, the hydrogen bond donor additive and the diluent is (18-23): (2-5): (73-82).

3. The method for preparing a polyketone separation membrane based on hydrogen bond regulation according to claim 1, characterized in that: The hydrogen bond donor additive is ethylene glycol, gallic acid, propylene glycol, catechol or formamide.

4. The method for preparing a polyketone separation membrane based on hydrogen bond regulation according to claim 1, characterized in that: The diluent is DMSO, NMP or DMI.

5. The method for preparing a polyketone separation membrane based on hydrogen bond regulation according to claim 1, characterized in that: The film-forming form of the casting liquid is a flat membrane or a hollow fiber membrane.

6. The method for preparing a polyketone separation membrane based on hydrogen bond regulation according to claim 1, characterized in that: The mixing and heating temperature of the polyketone, hydrogen bond donor additive and diluent is 120°C to 160°C.

7. The method for preparing a polyketone separation membrane based on hydrogen bond regulation according to claim 1, characterized in that: The cooling bath temperature is 40°C to 60°C.

8. The method for preparing a polyketone separation membrane based on hydrogen bond regulation according to claim 1, characterized in that: The mass fraction of the glycerol aqueous solution is 20%.

9. A polyketone separation membrane based on hydrogen bond regulation, characterized in that: The polyketone separation membrane is prepared using the method for preparing a polyketone separation membrane based on hydrogen bond regulation as described in any one of claims 1 to 8.

10. Use of the polyketone separation membrane based on hydrogen bond regulation according to claim 9 in organic separation and purification, filtration and sterilization, and wastewater treatment.

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