Sulfonyl covalent organic framework-amide composite membrane as well as preparation and application thereof

Abstract

The invention relates to a sulfonic covalent organic framework-amide composite membrane and preparation and application thereof.The preparation method comprises the steps that a substrate material is soaked in a 1, 3, 5-trimesoyl chloride TMC solution and then soaked in a mixed solution of tris (2-aminoethyl) amine TREN and sulfonic COF nanosheets, reaction and drying are conducted, and the sulfonic covalent organic framework-amide composite membrane is obtained. The sulfonic covalent organic framework-amide composite membrane is synthesized by using an interfacial polymerization method, the operation is simple and convenient, the obtained membrane material has a good separation effect, and the sulfonic covalent organic framework-amide composite membrane has a good application prospect in the aspects of pervaporation ethanol dehydration, separation and purification of other intersoluble azeotropic mixtures and the like.

Description

Technical Field

[0001] The present invention belongs to the field of functional membranes, and particularly relates to a sulfonic acid group covalent organic framework-amide composite membrane and its preparation and application. Background Art

[0002] Membrane separation technology features high energy efficiency, low carbon emissions, and high design flexibility, and has developed into an effective and sustainable important technology for alleviating global water shortages, environmental remediation, and resource recovery. The key to membrane separation technology lies in the selection of membrane materials. High-performance membrane materials should have high rejection rates, high permeation rates, and long-term operational stability under actual harsh conditions.

[0003] Covalent organic frameworks (COFs) are a class of crystalline porous polymers constructed from organic building units through covalent bonds. They exist in two-dimensional or three-dimensional structures. In particular, two-dimensional COFs have become potential candidates for membrane separation materials due to their inherent porosity, uniform pores, adjustable pore sizes, and excellent chemical stability. Covalent organic framework membranes with tunable ordered channels and free organic groups have great application prospects in molecular separation due to the synergistic effect of their physical and chemical microenvironments.

[0004] The intrinsic pore size of COFs is mostly 1-2 nm, belonging to the microporous range. For miscible azeotropic mixtures (such as water / alcohol, alcohol / ether, ester / alkane, etc.), relying solely on the COF pores is not sufficient to achieve effective separation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a sulfonic acid group covalent organic framework-amide composite membrane and its preparation and application.

[0006] The present invention provides a preparation method of a sulfonic acid group covalent organic framework-amide composite membrane, comprising:

[0007] Immersing a substrate material in a 1,3,5-benzenetricarbonyl chloride (TMC) solution, then immersing it in a mixed solution of tris(2-aminoethyl)amine (TREN) and sulfonic acid group COF nanosheets, reacting, and drying to obtain a sulfonic acid group covalent organic framework-amide composite membrane.

[0008] Further, the substrate material includes a polyacrylonitrile membrane.

[0009] Preferably, the solvent of the TMC solution includes chloroform; the concentration of the TMC solution is 0.1-3 wt%.

[0010] Preferably, the mixed solution of TREN and sulfonic acid group COF nanosheets: a water dispersion of sulfonic acid group COF nanosheets and a TREN solution are mixed and stirred; wherein the concentration of the TREN solution is 1-10 mg mL -1。

[0011] Further, the mixed solution of tris(2-aminoethyl)amine TREN and sulfonic acid group COF nanosheets includes: taking the TpSO3H-CON aqueous dispersion, preparing the TREN solution, and adjusting the pH value to 7-8; mixing the TpSO3H-CON dispersion and the TREN solution, and stirring for 3-5 h; wherein the concentration of the prepared TREN solution is 1-10 mg mL -1 ; wherein the volume ratio of the TpSO3H-CON aqueous dispersion to the TREN solution is 2:1.

[0012] Further, the sulfonic acid group COF nanosheets are obtained by interfacial polymerization from an aqueous solution containing 2,5-diaminobenzenesulfonic acid, 1,3,5-triformylphloroglucinol, and n-octanoic acid to obtain sulfonic acid group COF nanosheets Tp-SO3H-CON.

[0013] The preparation of the sulfonic acid group COF nanosheets includes: using the aqueous solution of 2,5-diaminobenzenesulfonic acid as the aqueous phase, mixing 1,3,5-triformylphloroglucinol and n-octanoic acid, after ultrasonic treatment, adding them to the aqueous phase as the upper layer, and reacting at room temperature for 24-72 h (as the amine monomer is consumed and TpSO3H-CON grows in the bottom aqueous phase, the color of the aqueous solution gradually changes from purple to dark red). After the reaction, the two phases are separated and dialyzed to obtain sulfonic acid group COF nanosheets Tp-SO3H-CON.

[0014] The solvent water in the aqueous solution of 2,5-diaminobenzenesulfonic acid is ultrapure water; the ultrasonic treatment time is 25-35 min; the dialysis treatment is 12-24 h, and the molecular weight cut-off of the dialysis bag is 1000 Da.

[0015] The volume ratio of the ultrapure water as the solvent of the aqueous solution of 2,5-diaminobenzenesulfonic acid to n-octanoic acid is 100-150:50-100.

[0016] The molar ratio of 2,5-diaminobenzenesulfonic acid to 1,3,5-triformylphloroglucinol is (2.8-3.2):2.

[0017] The time for the substrate material to be impregnated with the 1,3,5-benzenetricarbonyl trichloride TMC solution is 5-15 min.

[0018] The reaction time is 3-6 min.

[0019] The drying is carried out at 35-45 °C.

[0020] The present invention provides a sulfonic acid group covalent organic framework-amide composite membrane prepared by the above method.

[0021] The present invention provides an application of the sulfonic acid group covalent organic framework-amide composite membrane in pervaporation and the separation and purification of miscible azeotropic mixtures, such as pervaporation ethanol dehydration.

[0022] The present invention prepares a sulfonic acid group covalent organic framework-amide composite membrane ((SO3H) CON-TNC) by a secondary interfacial polymerization method. The obtained (SO3H) CON-TNC membrane has excellent pervaporation performance and can maintain good stability during long-term operation. Compared with other membrane materials, the method of the present invention is simple to operate, and the "secondary interface" assembled (SO3H) CON-TNC membrane prepared has good application prospects in aspects such as pervaporation ethanol dehydration.

[0023] Beneficial effects

[0024] The present invention synthesizes a sulfonic acid group covalent organic framework-amide composite membrane by "secondary interface" assembly. This method is simple to operate and has good long-term operation stability, and has good application prospects in aspects such as pervaporation ethanol dehydration and the separation and purification of other miscible azeotropic mixtures.

[0025] The present invention provides a synthesis method of a sulfonic acid group covalent organic framework-amide composite membrane for pervaporation, and explores the performance differences of the obtained sulfonic acid group covalent organic framework-amide composite membrane under different reaction conditions. This method is simple to operate, and the obtained sulfonic acid group covalent organic framework-amide composite membrane has a wide range of applications and has good application prospects in aspects such as pervaporation ethanol dehydration and the separation and purification of other miscible azeotropic mixtures.

[0026] The present invention proposes a strategy of one-time interface plus secondary interface polymerization to manufacture a covalent organic framework-amide composite membrane for pervaporation. The prepared sulfonic acid group covalent organic framework-amide composite membrane has a high water permeation flux and can perform efficient pervaporation alcohol-water separation to achieve more energy-efficient and efficient ethanol separation and purification. Description of the drawings

[0027] Figure 1 It is the Fourier transform infrared spectrum of the Tp-SO3H nanosheets and the TNC membrane obtained in the examples;

[0028] Figure 2 It is the Fourier transform infrared spectrum of the (SO3H) CON-TNC membrane obtained in the examples;

[0029] Figure 3 It is the powder C13 nuclear magnetic resonance spectrum of the Tp-SO3H nanosheet membrane obtained in the examples;

[0030] Figure 4 It is the X-ray diffraction spectrum of the Tp-SO3H nanosheets obtained in the examples;

[0031] Figure 5 The X-ray diffraction pattern of the (SO3H) CON-TNC membrane obtained in the example;

[0032] Figure 6 The X-ray photoelectron spectroscopy of the (SO3H) CON-TNC membrane obtained in the example;

[0033] Figure 7 The thermogravimetric analysis of the (SO3H) CON-TNC membrane obtained in the example;

[0034] Figure 8 The pervaporation water permeation and the corresponding water / ethanol separation factor of the TNC membrane and the (SO3H) CON-TNC membrane obtained in the example;

[0035] Figure 9 The pervaporation water permeation and the corresponding water / ethanol separation factor of the TNC membrane and the (SO3H) CON-TNC membrane obtained in the example at different temperatures. Detailed implementation manners

[0036] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0037] Example 1

[0038] The preparation of Tp-SO3H nanosheets, the specific steps are as follows: Dissolve 2,5-diaminobenzenesulfonic acid (DABA, 141 mg, 0.75 mmol) in 150 ml of ultrapure water and pour it into a beaker as the aqueous phase. Dissolve TFP (105 mg, 0.50 mmol) in 100 mL of n-caprylic acid, sonicate for 30 minutes, and then slowly add it to the beaker as the upper layer. React at room temperature for 72 hours. As the amine monomer is consumed and TpSO3H-CON grows in the bottom aqueous phase, the color of the aqueous solution gradually changes from purple to dark red. After the reaction, separate the two phases, and dialyze the aqueous phase TpSO3H-CON in ultrapure water for 24 hours (dialysis bag molecular weight 1000 Da). Obtain Tp-SO3H nanosheets, denoted as TpSO3H-CON.

[0039] The Fourier transform infrared spectrum of the TpSO3H-CON obtained in this example is as Figure 1 shown. In the FT-IR spectrum of the covalent organic framework, at 1204 cm -1The characteristic stretching vibration absorption peak of the C-N bond appears at 1575 cm -1 The characteristic stretching vibration absorption peak of the C=C bond appears at [location], indicating the successful synthesis of the covalent organic framework membrane and the generation of enol-keto tautomerism.

[0040] The nuclear magnetic resonance spectrum of TpSO3H-CON obtained in this example is as Figure 3 shown. The characteristic peaks at 185, 147, and 105 ppm correspond to the carbon atom chemical shifts of ketone (-C=O), ketone amide (-C-NH-), and exocyclic carbon (C=C), respectively, indicating the successful synthesis of the covalent organic framework membrane and the generation of enol-keto tautomerism.

[0041] The powder X-ray diffraction pattern of TpSO3H-CON obtained in this example is as Figure 4 shown. The XRD pattern of TpSO3H-CON shows obvious diffraction peaks at 2θ = 4.7° and 27.1°, corresponding to the (100) and (001) crystal planes, respectively. The XRD test results match well with the simulated image of the AA stacking of the covalent organic framework, indicating that the obtained covalent organic framework thin film has a high crystallinity.

[0042] Example 2

[0043] The preparation of the TNC polyamide membrane is as follows: Prepare a 0.15 wt% chloroform solution of 1,3,5-benzenetricarbonyl chloride (TMC) and an aqueous solution of 5 mmol mL-1 tris(2-aminoethyl)amine (TREN). Subsequently, immerse the polyacrylonitrile support substrate membrane in the 0.15 wt% TMC chloroform solution for 10 minutes and then lift it out. Then immerse the polyacrylonitrile substrate membrane soaked in the TMC solution in the TREN aqueous solution. React for 5 minutes and transfer it to an oven at 40 °C to obtain the TNC membrane, denoted as TNC. The Fourier transform infrared spectrum of the TNC membrane obtained in this example is as Figure 1 shown. The characteristic stretching vibration absorption peak of the -C-NH bond appears at 1266 cm -1 The characteristic absorption peak at [location] is the stretching vibration peak of the C=O bond. The characteristic absorption peak at 2867 cm -1 is attributed to the stretching vibration of the -CH2 bond on the TREN monomer. The stretching vibration absorption peak of the -NH2 bond (3380 cm -1 ) of the monomer TREN disappears, indicating that the acyl chloride and the amino group undergo a condensation reaction to form an amide bond. -1

[0044] Example 3

[0045] The preparation of the (SO3H) CON-TNC membrane is as follows:

[0046] Prepare a mixed solution of TREN and TpSO3H-CON. Take 10 mL of the TpSO3H-CON aqueous dispersion; prepare a TREN solution with a concentration of 1 mg mL -1 and adjust the pH value to 7-8. Then mix 10 mL of the TpSO3H-CON aqueous dispersion and 5 mL of the TREN solution with a concentration of 1 mg mL -1 and stir for 5 hours.

[0047] Immerse the polyacrylonitrile supported substrate membrane in a 0.15 wt% TMC chloroform solution for 10 minutes and then lift it out. Then immerse the polyacrylonitrile substrate membrane soaked in the TMC solution in the mixed solution of TREN and TpSO3H-CON, react for 5 minutes, and transfer it to a 40 °C oven to dry to obtain the (SO3H) CON-TNC membrane, denoted as (SO3H) CON-TNC-1.

[0048] The Fourier transform infrared spectrum of (SO3H) CON-TNC-1 obtained in this example is as Figure 2 shown. The characteristic peaks at 1244 cm -1 and 1630 cm -1 are the stretching vibration absorption peaks of the -C-NH- bond and C=O bond in TpSO3H-CON. The stretching vibration absorption peak of the -CH2 bond appears at 2867 cm -1 , while the infrared absorption peak of the -NH3 -1 bond appears at 3067 cm + , indicating that protonation occurs between TpSO3H-CON and TREN and a condensation reaction occurs with the acyl chloride.

[0049] The powder X-ray diffraction pattern of (SO3H) CON-TNC-1 obtained in this example is as Figure 5 shown. Obvious diffraction peaks appear at 2θ = 4.7° and 27.0°, corresponding to the (100) and (001) crystal planes respectively. The XRD test results match well with the simulated image of the AA stacking of the covalent organic framework, indicating that the obtained (SO3H) CON-TNC membrane has a high crystallinity.

[0050] The X-ray photoelectron spectroscopy of (SO3H) CON-TNC-1 obtained in this example is as shown in Figure 6. The N 1s photoelectron spectrum of (SO3H) CON-TNC-1 is deconvoluted into two separate peaks at 399.6 - 399.8 eV and 401.6 - 401.7 eV, attributed to amide N (-C-HN-) and quaternary ammonium salt N + (-NH3 + ), indicating that protonation occurs between TpSO3H-CON and TREN.

[0051] Example 4

[0052] Preparation of (SO3H) CON-TNC membrane, the specific steps are as follows: Prepare a mixed solution of TREN and TpSO3H-CON, and take 10 mL of TpSO3H-CON aqueous dispersion; prepare a TREN solution with a concentration of 2 mg / mL -1 and adjust the pH value to 7-8. Mix 10 mL of TpSO3H-CON aqueous dispersion and 5 mL of TREN solution with a concentration of 2 mg / mL -1 and stir for 5 hours.

[0053] Immerse the polyacrylonitrile support substrate membrane in a 0.15 wt% TMC chloroform solution for 10 minutes and then lift it out. Then immerse the polyacrylonitrile substrate membrane soaked in the TMC solution in the mixed solution of TREN and TpSO3H-CON, react for 5 minutes, and transfer it to a 40 °C oven to dry to obtain the (SO3H) CON-TNC membrane, denoted as (SO3H) CON-TNC-2.

[0054] The Fourier transform infrared spectrum of (SO3H) CON-TNC-2 obtained in this example is as Figure 2 shown. The characteristic peaks at 1244 cm -1 and 1630 cm -1 are the stretching vibration absorption peaks of -C-NH- bond and C=O bond in TpSO3H-CON. The stretching vibration absorption peak of -CH2 bond appears at 2867 cm -1 , while the infrared absorption peak of -NH3 -1 bond appears at 3067 cm + , indicating that protonation occurs between TpSO3H-CON and TREN, and a condensation reaction occurs with acyl chloride.

[0055] The powder X-ray diffraction pattern of (SO3H) CON-TNC-2 obtained in this example is as Figure 5 shown. Obvious diffraction peaks appear at 2θ = 4.7° and 27.0°, corresponding to the (100) and (001) crystal planes respectively. The XRD test results match well with the simulated image of the AA stacking of covalent organic frameworks, indicating that the obtained (SO3H) CON-TNC membrane has a high crystallinity.

[0056] The X-ray photoelectron spectroscopy of (SO3H) CON-TNC-2 obtained in this example is as shown in Figure 6. The N 1s photoelectron spectrum of (SO3H) CON-TNC-1 is deconvoluted into two separate peaks at 399.6-399.8 eV and 401.6-401.7 eV, attributed to amide N (-C-HN-) and quaternary ammonium salt N + (-NH3 +) indicates that protonation occurs between TpSO3H-CON and TREN.

[0057] Example 5

[0058] (SO3H) CON-TNC membrane was prepared. The specific steps were as follows: Prepare a mixed solution of TREN and TpSO3H-CON, and take 10 mL of the TpSO3H-CON aqueous dispersion; prepare a TREN solution with a concentration of 4 mg mL -1 and adjust the pH value to 7 - 8. Mix 10 mL of the TpSO3H-CON aqueous dispersion and 5 mL of the TREN solution with a concentration of 4 mg mL -1 and stir for 5 hours.

[0059] Immerse the polyacrylonitrile support substrate membrane in a 0.15 wt% TMC chloroform solution for 10 minutes and then lift it out. Then immerse the polyacrylonitrile substrate membrane soaked in the TMC solution into the mixed solution of TREN and TpSO3H-CON. React for 5 minutes and transfer it to a 40 °C oven to dry to obtain the (SO3H) CON-TNC membrane, denoted as (SO3H) CON-TNC-3.

[0060] The Fourier transform infrared spectrum of (SO3H) CON-TNC-3 obtained in this example is as Figure 2 shown. The characteristic peaks at 1244 cm -1 and 1630 cm -1 are the stretching vibration absorption peaks of the -C-NH- bond and C=O bond in TpSO3H-CON. The stretching vibration absorption peak of the -CH2 bond appears at 2867 cm -1 , while the infrared absorption peak of the -NH3 -1 bond appears at 3067 cm + , indicating that protonation occurs between TpSO3H-CON and TREN and a condensation reaction occurs with the acyl chloride.

[0061] The powder X-ray diffraction pattern of (SO3H) CON-TNC-3 obtained in this example is as Figure 5 shown. Obvious diffraction peaks appear at 2θ = 4.7° and 27.0°, corresponding to the (100) and (001) crystal planes respectively. The XRD test results match well with the simulated image of the AA stacking of the covalent organic framework, indicating that the obtained (SO3H) CON-TNC membrane has a high crystallinity.

[0062] The X-ray photoelectron spectroscopy of (SO3H) CON-TNC-3 obtained in this example is shown in Figure 6. The N 1s photoelectron spectroscopy of (SO3H) CON-TNC-1 is deconvoluted into two separate peaks at 399.6 - 399.8 eV and 401.6 - 401.7 eV, attributed to amide N (-C-HN-) and quaternary ammonium salt N + (-NH3 + ), indicating that protonation occurs between TpSO3H-CON and TREN.

[0063] Example 6

[0064] Preparation of the (SO3H) CON-TNC membrane, the specific steps are as follows: Prepare a mixed solution of TREN and TpSO3H-CON, take 10 mL of the TpSO3H-CON aqueous dispersion; prepare a TREN solution with a concentration of 6 mg mL -1 and adjust the pH value to 7 - 8. Mix 10 mL of the TpSO3H-CON aqueous dispersion and 5 mL of the TREN solution with a concentration of 6 mg mL -1 and stir for 5 hours.

[0065] Immerse the polyacrylonitrile support substrate membrane in a 0.15 wt% TMC chloroform solution for 10 minutes and then lift it out. Then immerse the polyacrylonitrile substrate membrane soaked in the TMC solution in the mixed solution of TREN and TpSO3H-CON. React for 5 minutes and transfer it to an oven at 40 °C to dry to obtain the (SO3H) CON-TNC membrane, denoted as (SO3H) CON-TNC-4.

[0066] The Fourier transform infrared spectrum of (SO3H) CON-TNC-4 obtained in this example is shown in Figure 2. The characteristic peaks at 1244 cm -1 and 1630 cm -1 are the stretching vibration absorption peaks of the -C-NH- bond and C=O bond in TpSO3H-CON. The stretching vibration absorption peak of the -CH2 bond appears at 2867 cm -1 , while the infrared absorption peak of the -NH3 -1 bond appears at 3067 cm + , indicating that protonation occurs between TpSO3H-CON and TREN and a condensation reaction occurs with acyl chloride.

[0067] The powder X-ray diffraction pattern of (SO3H) CON-TNC-4 obtained in this example is as Figure 5As shown, obvious diffraction peaks appear at 2θ = 4.7° and 27.0°, corresponding to the (100) and (001) crystal planes respectively. The XRD test results match well with the simulated image of the AA stacking of the covalent organic framework, indicating that the obtained (SO3H) CON-TNC membrane has a high crystallinity.

[0068] The X-ray photoelectron spectroscopy of (SO3H) CON-TNC-4 obtained in this example is shown in Figure 6. The N 1s photoelectron spectroscopy of (SO3H) CON-TNC-1 is deconvoluted into two separate peaks at 399.6 - 399.8 eV and 401.6 - 401.7 eV, attributed to amide N (-C-HN-) and quaternary ammonium salt N + (-NH3 + ), indicating that protonation occurs between TpSO3H-CON and TREN.

[0069] Example 7

[0070] The preparation of the (SO3H) CON-TNC membrane specifically includes the following steps: Prepare a mixed solution of TREN and TpSO3H-CON, and take 10 mL of the TpSO3H-CON aqueous dispersion; Prepare a TREN solution with a concentration of 10 mg mL -1 , and adjust the pH value to 7 - 8. Mix 10 mL of the TpSO3H-CON aqueous dispersion and 5 mL of the TREN solution with a concentration of 10 mg mL -1 , and stir for 5 hours.

[0071] Immerse the polyacrylonitrile support substrate membrane in a 0.15 wt% TMC chloroform solution for 10 minutes and then lift it out. Then immerse the polyacrylonitrile substrate membrane soaked in the TMC solution into the mixed solution of TREN and TpSO3H-CON. React for 5 minutes, and transfer it to a 40 °C oven to dry to obtain the (SO3H) CON-TNC membrane, denoted as (SO3H) CON-TNC-5.

[0072] The Fourier transform infrared spectrum of (SO3H) CON-TNC-5 obtained in this example is as Figure 2 shown. The characteristic peaks at 1244 cm -1 and 1630 cm -1 are the stretching vibration absorption peaks of the -C-NH- bond and C=O bond in TpSO3H-CON. The stretching vibration absorption peak of the -CH2 bond appears at 2867 cm -1 , while the infrared absorption peak of the -NH3 -1 bond appears at 3067 cm + , indicating that protonation occurs between TpSO3H-CON and TREN, and a condensation reaction occurs with the acyl chloride.

[0073] The powder X-ray diffraction pattern of (SO3H) CON-TNC-5 obtained in this example is as follows Figure 5 shown. Obvious diffraction peaks appear at 2θ = 4.7° and 27.0°, corresponding to the (100) and (001) crystal planes respectively. The XRD test results match well with the simulated image of the AA stacking of the covalent organic framework, indicating that the obtained (SO3H) CON-TNC membrane has a high crystallinity.

[0074] The X-ray photoelectron spectroscopy of (SO3H) CON-TNC-5 obtained in this example is shown in Figure 6. The N 1s photoelectron spectrum of (SO3H) CON-TNC-1 is deconvoluted into two separate peaks at 399.6 - 399.8 eV and 401.6 - 401.7 eV, attributed to amide N (-C-HN-) and quaternary ammonium salt N + (-NH3 + ), indicating that protonation occurs between TpSO3H-CON and TREN.

[0075] The thermogravimetric analysis diagrams of the COF membranes obtained in Examples 3 to 7 are as follows Figure 7 shown. The results show that the thermal decomposition temperatures of (SO3H) CON-TNC-1, 2, 3, 4, 5 in N2 atmosphere are 370, 365, 368, 363, 362 °C respectively. The (SO3H) CON-TNC membrane exhibits excellent thermal stability. The weight loss rate of the TNC membrane is about 13% at 193 °C, while the weight loss rate of the (SO3H) CON-TNC membrane is only 8% - 10%. Before the thermal decomposition temperature, the weight loss rate of the TNC membrane is much greater than that of the (SO3H) CON-TNC membrane. The final mass retention rate of the (SO3H) CON-TNC membrane is higher than that of the TNC membrane. These experimental results fully prove that TpSO3H-CON has been successfully introduced into the membrane.

[0076] Example 8

[0077] Pervaporation performance test. The pervaporation separation performance of the (SO3H) CON-TNC membrane for the water / ethanol azeotropic mixture was tested: The pervaporation separation performance test was carried out under the experimental conditions of ethanol and water with a mass ratio of 90:10 wt% at 60 °C. The test results are as follows Figure 8 shown. The water permeation flux of the original TNC membrane is only 1.91 kg m -2 h -1 . The hydrophobic layer on the surface of the TNC membrane results in a low water permeation flux of the TNC and a small separation factor (α water / ethanol) of 275.

[0078] The water permeation fluxes and separation factors of the (SO3H) CON-TNC 1, 2, 3, 4, 5 membranes are significantly improved, being 7.9, 5.09, 4.76, 3.31, 2.83 kg m -2 h -1 , respectively. The corresponding separation factors (α water / ethanol) are 299, 9312, 10585, 10697, 11121, respectively. Among them, the (SO3H) CON-TNC-3 membrane has the highest water permeation flux and separation factor, with a separation factor as high as 10585 and a permeate water flux of 4.76 kg m -2 h -1 .

[0079] Example 9

[0080] Vapor permeation performance test. The specific steps are as follows: the vapor permeation separation performance of the (SO3H) CON-TNC-3 membrane for azeotropic mixtures of water / ethanol (at different temperatures) was tested. As Figure 9 shown, as the temperature increases, the water permeation flux of the membrane gradually increases. Especially when the temperature reaches 60 °C, the water permeation flux of the membrane is significantly improved compared with that at lower temperatures. The permeate water flux at 60 °C can reach 4.7 kg m -2 h -1 .

Claims

1. A preparation method of a sulfonic acid group covalent organic framework-amide composite membrane, comprising: Immersing a substrate material in a 1,3,5-benzenetricarbonyl chloride (TMC) solution, then immersing it in a mixed solution of tris(2-aminoethyl)amine (TREN) and sulfonic acid group COF nanosheets, reacting, and drying to obtain a sulfonic acid group covalent organic framework-amide composite membrane.

2. The preparation method according to claim 1, wherein The substrate material includes a polyacrylonitrile membrane.

3. The preparation method according to claim 1, wherein, The solvent of the TMC solution includes chloroform; the concentration of the TMC solution is 0.1-3 wt%.

4. The preparation method according to claim 1, characterized in that, The mixed solution of TREN and sulfonic acid group COF nanosheets: Aqueous dispersion of sulfonic acid group COF nanosheets and TREN solution are mixed and stirred.

5. The preparation method according to claim 1, characterized in that, The sulfonic acid group COF nanosheets are obtained by interfacial polymerization using an aqueous solution containing 2,5-diaminobenzenesulfonic acid, 1,3,5-triformylphloroglucinol, and n-octanoic acid as raw materials to obtain sulfonic acid group COF nanosheets Tp-SO3H-CON.

6. The preparation method according to claim 5, characterized in that, The preparation of the sulfonic acid group COF nanosheets includes: Using an aqueous solution of 2,5-diaminobenzenesulfonic acid as the aqueous phase, mixing 1,3,5-triformylphloroglucinol and n-octanoic acid, ultrasonically dispersing, and then adding it to the aqueous phase as the upper layer, reacting at room temperature for 24-72 h, separating and dialyzing to obtain sulfonic acid group COF nanosheets Tp-SO3H-CON.

7. The preparation method according to claim 5, characterized in that, The molar ratio of 2,5-diaminobenzenesulfonic acid to 1,3,5-triformylphloroglucinol is (2.8-3.2):

2.

8. According to the preparation method described in claim 1, wherein, The time for the substrate material to be immersed in the 1,3,5-benzenetricarbonyl chloride (TMC) solution is 5-15 min; The reaction time is 3-6 min.

9. A sulfonic acid group covalent organic framework-amide composite membrane prepared by the method according to any one of claims 1-8.

10. An application of the sulfonic acid group covalent organic framework-amide composite membrane according to claim 9 in pervaporation and separation and purification of miscible azeotropic mixtures.

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