Hydrogen-bonded organic framework material composite membrane and preparation method therefor and use thereof

Abstract

A hydrogen-bonded organic framework material composite membrane and a preparation method therefor and a use thereof, relating to the technical field of membrane separation. The preparation method for the hydrogen-bonded organic framework material composite membrane comprises: dissolving a hydrogen-bonded organic framework material in a first solvent to obtain a hydrogen-bonded organic framework material solution; dissolving graphene oxide in a second solvent to obtain a graphene oxide solution; mixing the hydrogen-bonded organic framework material solution and the graphene oxide solution, bringing to a constant volume, and then performing ultrasonic treatment to obtain a uniformly mixed GO / HOF composite solution; and filtering the GO / HOF composite solution onto the surface of a base membrane by means of a vacuum filtration method, and utilizing hydrogen bonds and π-π conjugation between a hydrogen-bonded organic framework and graphene oxide to form a structurally uniform composite membrane. The preparation method has simple operations and mild preparation conditions, and the prepared hydrogen-bonded organic framework material composite membrane has a larger flux and better rejection performance.

Description

Hydrogen-bonded organic framework composite membranes, their preparation methods and applications Technical Field

[0001] This invention belongs to the field of membrane separation technology, specifically relating to a hydrogen-bonded organic framework material composite membrane, its preparation method, and its application. Background Technology

[0002] In recent years, researchers have proposed various research directions for novel membrane materials. Hydrogen-bonded organic frameworks (HOFs) are crystalline porous materials constructed from organic or metal-organic building blocks through hydrogen bonds. Due to their unique structural characteristics, such as high specific surface area, tunable pore size, and good thermal and chemical stability, they have become a popular direction in membrane material development. However, in most cases, HOFs exist in the form of fine powders or tiny particles, which makes them poorly dispersible in aqueous phases and difficult to self-assemble into membranes. Directly growing HOFs on membranes leads to unavoidable inter-membrane defects and uneven distribution on the membrane surface due to the non-directional and rapid crystallization of HOFs, thus affecting the separation performance and stability of the membrane.

[0003] Therefore, in view of the above shortcomings, this invention is proposed. Summary of the Invention

[0004] The main objective of this invention is to propose a hydrogen-bonded organic framework composite membrane, its preparation method, and its application. The preparation method of the hydrogen-bonded organic framework composite membrane provided by this invention is simple to operate and has mild preparation conditions. The prepared hydrogen-bonded organic framework composite membrane has a large flux and better retention performance.

[0005] The first aspect of this invention provides a method for preparing a hydrogen-bonded organic framework (GO / HOF) composite membrane. The method includes: dissolving a GO / HOF material in a first solvent to obtain a GO / HOF material solution; dissolving graphene oxide in a second solvent to obtain a graphene oxide solution; mixing and adjusting the volume of the GO / HOF material solution and the graphene oxide solution, followed by ultrasonic treatment to obtain a uniformly mixed GO / HOF composite solution; and filtering the GO / HOF composite solution onto the surface of a substrate membrane using a vacuum filtration method, thereby forming a structurally uniform composite membrane by utilizing the hydrogen bonds and π-π conjugation between the GO / HOF material and the graphene oxide.

[0006] In some embodiments of the present invention, the hydrogen-bonded organic framework material is prepared by dissolving 5,10,15,20-tetra(4-carboxyphenyl)porphyrin monomer in a mixed solvent of N,N-dimethylacetamide and methanol, and then reacting the solvent by solvent evaporation.

[0007] In some embodiments of the present invention, the reaction temperature of the solvent evaporation reaction is 50°C to 70°C, and the reaction time is 20h to 30h.

[0008] In some embodiments of the present invention, the mass ratio of the graphene oxide to the hydrogen-bonded organic framework material in the GO / HOF composite solution is 1:2 to 8.

[0009] In some embodiments of the present invention, the total volume of the GO / HOF complex solution is 10 mL to 40 mL.

[0010] In some embodiments of the present invention, the ultrasonic frequency of the ultrasonic treatment is 30kHz to 40kHz, the ultrasonic time is 10min to 20min, and the ultrasonic treatment volume is 10mL to 40mL.

[0011] In some embodiments of the present invention, the first solvent and the second solvent are each independently selected from one of methanol, ethanol, and deionized water.

[0012] In some embodiments of the present invention, the base membrane is selected from one of cellulose acetate membrane, nylon membrane, and polytetrafluoroethylene membrane.

[0013] The second aspect of the present invention provides a hydrogen-bonded organic framework material composite film, which is prepared by the method for preparing hydrogen-bonded organic framework material composite film described in the first aspect, and is formed by a composite structure of hydrogen-bonded organic framework material and graphene oxide.

[0014] The third aspect of this invention provides an application of the hydrogen-bonded organic framework composite membrane described in the second aspect, or the hydrogen-bonded organic framework composite membrane prepared by the preparation method of the hydrogen-bonded organic framework composite membrane described in the first aspect, in water purification.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] This invention combines hydrogen-bonded organic framework (HBO) materials with graphene oxide (BOO) sheets to form a high-performance HBO composite membrane. On one hand, the carboxyl groups on the organic monomers in the porous rod-shaped HBO material can form hydrogen bonds and conjugation interactions with the carboxyl groups or hydroxyl groups in the BOO sheets, enhancing the interlayer bonding force and increasing the HOF loading in the composite membrane. On the other hand, the high porosity of the HBO material reduces solute transport resistance while providing additional water transport channels, significantly improving membrane permeability. The combination of these two aspects allows the HBO composite membrane to maintain good retention performance for dyes and micropollutants in water while maintaining high water permeability.

[0017] In the preparation method provided by this invention, the hydrogen-bonded organic framework material can be prepared in an aqueous solvent at a relatively low temperature, and the GO / HOF composite solution is simple to prepare. The composite membrane can be quickly prepared by vacuum filtration. The membrane preparation process is simple, does not require a large amount of organic solvent, and is inexpensive, and can be applied to large-scale industrial production.

[0018] The hydrogen-bonded organic framework composite membrane provided by this invention has high flux, excellent retention performance and antifouling ability, and is particularly suitable for water purification, wastewater treatment and other fields.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. In the drawings:

[0021] Figure 1 shows the separation performance of the GO / HOF composite membrane obtained in the embodiment of the present invention and the graphene oxide membrane obtained in Comparative Example 1.

[0022] Figure 2 shows scanning electron microscope (SEM) images of the GO / HOF composite film obtained in the embodiments of the present invention and the graphene oxide film obtained in Comparative Example 1. In Figure 2, a and f are SEM images of the graphene oxide film at 10 μm and 1 μm, respectively; b and g are SEM images of the GO / HOF-50 composite film at 10 μm and 1 μm, respectively; c and h are SEM images of the GO / HOF-200 composite film at 10 μm and 1 μm, respectively; d and i are SEM images of the GO / HOF-400 composite film at 10 μm and 1 μm, respectively; and e and j are SEM images of the GO / HOF-800 composite film at 10 μm and 1 μm, respectively.

[0023] Figure 3 shows the static water contact angle between the GO / HOF composite membrane obtained in the embodiment of the present invention and the graphene oxide membrane obtained in Comparative Example 1.

[0024] Figure 4 shows the retention performance of the GO / HOF-400 composite membrane obtained in the embodiments of the present invention for different micro-pollutants;

[0025] Figure 5 is a scanning electron microscope image of the HOF film obtained in Comparative Example 2 of the present invention. Detailed Implementation

[0026] Exemplary embodiments of the present invention will now be described in more detail with reference to specific examples. It should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the invention, are intended to cover non-exclusive inclusion.

[0028] In the description of the embodiments of the present invention, the technical terms "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] In the description of the embodiments of this invention, the term "and / or" is merely a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0031] In the description of the embodiments of the present invention, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0032] In most cases, HOF exists in the form of fine powder or tiny particles, which makes it poorly dispersed in the aqueous phase and difficult to self-assemble into a membrane. Directly growing HOF on a membrane inevitably leads to inter-membrane defects and uneven distribution on the membrane surface due to the rapid, non-directional crystallization of HOF.

[0033] In this invention, the processability of flexible materials is combined with the mixing of hydrogen-bonded organic framework materials and two-dimensional nanosheet graphene oxide materials to promote the film formation of hydrogen-bonded organic framework materials.

[0034] This invention provides a method for preparing hydrogen-bonded organic framework composite membranes that is simple to operate, has mild preparation conditions, and is widely applicable. The key to this method is to prepare a GO / HOF composite solution based on HOF and graphene oxide, and to use ultrasonic treatment to assist in its dispersion to obtain a uniformly mixed GO / HOF composite solution. Then, the GO / HOF composite solution is filtered onto the surface of a polymer substrate membrane by vacuum filtration, and a structurally uniform composite membrane is formed by utilizing the hydrogen bonding and π-π conjugation between HOF and graphene oxide.

[0035] The preparation method of the hydrogen-bonded organic framework material composite film in this invention is carried out according to the following steps.

[0036] 1) Preparation of hydrogen-bonded organic framework materials.

[0037] In an embodiment of the present invention, an organic solution containing a hydrogen-bonded organic framework material monomer is dissolved in a solvent and reacted by solvent evaporation to obtain a purple hydrogen-bonded organic framework material.

[0038] In some embodiments of the present invention, the hydrogen-bonded organic framework material is prepared by dissolving 5,10,15,20-tetra(4-carboxyphenyl)porphyrin monomer in a mixed solvent of N,N-dimethylacetamide and methanol, and then reacting the solvent by solvent evaporation.

[0039] In some embodiments of the present invention, the solvent evaporation reaction temperature is 50°C to 70°C, and the reaction time is 20h to 30h. Compared with the solvent evaporation reaction temperature in the prior art, which is in the range of 80°C to 250°C, the present invention has a lower preparation temperature. The design of the reaction temperature and time in the present invention can accelerate the solvent evaporation process, improve the crystallinity and phase purity of the HOF material, and obtain a more uniform crystal structure.

[0040] For example, the reaction temperature can be one of 50°C, 55°C, 60°C, 65°C, 70°C, or any value within the above range. The reaction time can be one of 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h, 30h, or any value within the above range.

[0041] 2) Preparation of hydrogen-bonded organic framework material solutions.

[0042] In an embodiment of the present invention, a hydrogen-bonded organic framework material is dissolved in a first solvent to obtain a hydrogen-bonded organic framework material solution.

[0043] In some embodiments of the present invention, the first solvent is selected from methanol, ethanol, and deionized water.

[0044] 3) Prepare graphene oxide solution.

[0045] In an embodiment of the present invention, graphene oxide is dissolved in a second solvent to obtain a graphene oxide solution.

[0046] In some embodiments of the present invention, the second solvent is selected from methanol, ethanol, and deionized water.

[0047] 4) Prepare GO / HOF complex solution.

[0048] In an embodiment of the present invention, a hydrogen-bonded organic framework material solution and a graphene oxide solution are mixed and brought to a constant volume, and then subjected to ultrasonic treatment to obtain a uniformly mixed GO / HOF composite solution.

[0049] In some embodiments of the present invention, a hydrogen-bonded organic framework material solution and a graphene oxide solution are added to a predetermined volume of deionized water or other solvent, and then subjected to ultrasonic treatment to obtain a uniformly mixed GO / HOF composite solution.

[0050] In some embodiments of the present invention, the ultrasonic frequency of the ultrasonic treatment is 30kHz to 40kHz, the ultrasonic time is 10min to 20min, and the ultrasonic treatment volume is 10mL to 40mL. Exemplarily, the ultrasonic frequency can be one of 30kHz, 31kHz, 32kHz, 33kHz, 34kHz, 35kHz, 36kHz, 37kHz, 38kHz, 39kHz, and 40kHz, or any value satisfying the above range. The ultrasonic time can be one of 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min, and 20min, or any value satisfying the above range. The ultrasonic treatment volume can be one of 10mL, 15mL, 20mL, 25mL, 30mL, 35mL, and 40mL, or any value satisfying the above range.

[0051] In some embodiments of the present invention, the mass ratio of graphene oxide to hydrogen-bonded organic framework material in the GO / HOF composite solution is 1:2 to 8. Exemplarily, the mass ratio of graphene oxide to hydrogen-bonded organic framework material can be one of 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, or 1:8, or any value satisfying the above range.

[0052] In some embodiments of the present invention, the total volume of the GO / HOF complex solution is 10 mL to 40 mL. Exemplarily, the total volume of the GO / HOF complex solution can be one of 10 mL, 15 mL, 20 mL, 25 mL, 30 mL, 35 mL, or 40 mL, or any value satisfying the above range.

[0053] 5) Filter to form a membrane.

[0054] In an embodiment of the present invention, the GO / HOF composite solution is filtered to the surface of the substrate membrane by vacuum filtration, and a composite membrane with uniform structure is formed by the hydrogen bonding and π-π conjugation between the hydrogen-bonded organic framework and the graphene oxide.

[0055] The GO / HOF composite solution is rapidly filtered onto the substrate membrane surface using a vacuum filtration method to form a composite membrane with a uniform structure and no defects. The preparation process does not require a large amount of organic solvent and has a low preparation cost.

[0056] In some embodiments of the present invention, the vacuum level of the vacuum filtration is 0.8 bar to 1.0 bar. Exemplarily, the vacuum level can be one of 0.8 bar, 0.9 bar, 1.0 bar, or any value satisfying the above range.

[0057] In some embodiments of the present invention, the base membrane is selected from one of cellulose acetate membrane, nylon membrane, and polytetrafluoroethylene membrane.

[0058] The present invention also provides a hydrogen-bonded organic framework material composite film, which is prepared by the above-mentioned preparation method of hydrogen-bonded organic framework material composite film. Specifically, the hydrogen-bonded organic framework material composite film is formed by composite construction of hydrogen-bonded organic framework material and graphene oxide.

[0059] The hydrogen-bonded organic framework composite membrane of this invention has excellent permeability, retention performance and antifouling ability, and is suitable for water purification, wastewater treatment or other membrane separation applications.

[0060] The composite membrane described above in this invention, or the composite membrane prepared by the above-described composite membrane preparation method, can be used in water purification to efficiently retain pollutants in water, such as dyes and micro-pollutants in the water, while maintaining high water permeability.

[0061] The hydrogen-bonded organic framework composite membrane provided by this invention has advantages such as high efficiency, low cost, and ease of large-scale production, and has broad application prospects.

[0062] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are all conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or through existing methods; unless otherwise specified, the amounts of experimental reagents used are the amounts used in conventional experimental operations; unless otherwise specified, the experimental methods are all conventional methods.

[0063] Example 1

[0064] A hydrogen-bonded organic framework composite film, formed by combining a hydrogen-bonded organic framework material with graphene oxide, is prepared by the following method:

[0065] (1) Dissolve 236 mg of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin, 2 mL of N,N-dimethylacetamide and 20 mL of methanol thoroughly, and then place the resulting mixed solution at 60 °C for solvent evaporation for 24 h to obtain porous crystalline hydrogen-bonded organic framework material (HOF).

[0066] (2) Dissolve 20 μg of HOF material in 20 mL of deionized water to obtain an HOF aqueous solution with a concentration of 1 mg / mL. At the same time, dissolve 20 μg of graphene oxide material in 20 mL of deionized water to obtain an GO aqueous solution with a concentration of 1 mg / mL.

[0067] Add 100 μL of GO aqueous solution and 400 μL of HOF aqueous solution to 20 mL of deionized water, and sonicate for 10 min at a frequency of 35 kHz to obtain a homogeneous GO / HOF complex solution.

[0068] (3) The GO / HOF composite solution obtained in step (2) was vacuum filtered to the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. The vacuum degree was 1.0 bar. After filtration, the resulting composite membrane was dried at room temperature and was named GO / HOF-400 composite membrane.

[0069] Example 2

[0070] A hydrogen-bonded organic framework composite film, formed by combining a hydrogen-bonded organic framework material with graphene oxide, is prepared by the following method:

[0071] (1) Dissolve 236 mg of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin, 2 mL of N,N-dimethylacetamide and 20 mL of methanol thoroughly, and then place the resulting mixed solution at 60 °C for solvent evaporation for 24 h to obtain porous crystalline hydrogen-bonded organic framework material (HOF).

[0072] (2) Dissolve 20 μg of HOF material in 20 mL of deionized water to obtain an HOF aqueous solution with a concentration of 1 mg / mL. At the same time, dissolve 20 μg of graphene oxide material in 20 mL of deionized water to obtain an GO aqueous solution with a concentration of 1 mg / mL.

[0073] Add 100 μL of GO aqueous solution and 200 μL of HOF aqueous solution to 20 mL of deionized water, and sonicate for 10 min at a frequency of 35 kHz to obtain a homogeneous GO / HOF complex solution.

[0074] (3) The GO / HOF composite solution obtained in step (2) was vacuum filtered to the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. The vacuum degree was 1.0 bar. After filtration, the resulting composite membrane was dried at room temperature and named GO / HOF-200 composite membrane.

[0075] Example 3

[0076] A hydrogen-bonded organic framework composite film, formed by combining a hydrogen-bonded organic framework material with graphene oxide, is prepared by the following method:

[0077] (1) Dissolve 236 mg of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin, 2 mL of N,N-dimethylacetamide and 20 mL of methanol thoroughly, and then place the resulting mixed solution at 60 °C for solvent evaporation for 24 h to obtain porous crystalline hydrogen-bonded organic framework material (HOF).

[0078] (2) Dissolve 20 μg of HOF material in 20 mL of deionized water to obtain an HOF aqueous solution with a concentration of 1 mg / mL. At the same time, dissolve 20 μg of graphene oxide material in 20 mL of deionized water to obtain an GO aqueous solution with a concentration of 1 mg / mL.

[0079] Add 100 μL of GO aqueous solution and 800 μL of HOF aqueous solution to 20 mL of deionized water, and sonicate for 10 min at a frequency of 35 kHz to obtain a homogeneous GO / HOF complex solution.

[0080] (3) The GO / HOF composite solution obtained in step (2) was vacuum filtered to the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. The vacuum degree was 1.0 bar. After filtration, the resulting composite membrane was dried at room temperature and was named GO / HOF-800 composite membrane.

[0081] Example 4

[0082] A hydrogen-bonded organic framework composite film, formed by combining a hydrogen-bonded organic framework material with graphene oxide, is prepared by the following method:

[0083] (1) Dissolve 236 mg of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin, 2 mL of N,N-dimethylacetamide and 20 mL of methanol thoroughly, and then place the resulting mixed solution at 60 °C for solvent evaporation for 24 h to obtain porous crystalline hydrogen-bonded organic framework material (HOF).

[0084] (2) Dissolve 20 μg of HOF material in 20 mL of deionized water to obtain an HOF aqueous solution with a concentration of 1 mg / mL. At the same time, dissolve 20 μg of graphene oxide material in 20 mL of deionized water to obtain an GO aqueous solution with a concentration of 1 mg / mL.

[0085] Add 100 μL of GO aqueous solution and 50 μL of HOF aqueous solution to 20 mL of deionized water, and sonicate for 10 min at a frequency of 35 kHz to obtain a homogeneous GO / HOF complex solution.

[0086] (3) The GO / HOF composite solution obtained in step (2) was vacuum filtered to the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. The vacuum degree was 1.0 bar. After filtration, the resulting composite membrane was dried at room temperature and named GO / HOF-50 composite membrane.

[0087] Comparative Example 1

[0088] A graphene oxide film, the preparation method of which is as follows:

[0089] (1) 100 μg of graphene oxide was fully dissolved in 20 mL of deionized water and ultrasonically treated for 10 min at a frequency of 35 kHz to ensure complete dissolution and obtain a uniform graphene oxide solution.

[0090] (2) The graphene oxide solution obtained in step (1) was vacuum filtered onto the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. The vacuum degree was 1.0 bar. After filtration, the formed membrane was dried at room temperature and denoted as GO membrane.

[0091] Comparative Example 2

[0092] A hydrogen-bonded organic framework material film is prepared by the following method:

[0093] (1) Dissolve 236 mg of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin, 2 mL of N,N-dimethylacetamide and 20 mL of methanol thoroughly, and then place the resulting mixed solution at 60 °C for solvent evaporation for 24 h to obtain porous crystalline hydrogen-bonded organic framework material (HOF).

[0094] (2) Dissolve 400 μg of HOF material in 20 mL of deionized water and sonicate for 10 min at a frequency of 35 kHz to ensure uniform dissolution and obtain HOF solution.

[0095] (3) The HOF solution obtained in step (2) is vacuum filtered onto the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. The vacuum degree is 1.0 bar. After filtration, the formed membrane is dried at room temperature and is called HOF membrane.

[0096] It is worth mentioning that the room temperature in the drying process refers to a temperature within the range of 20℃ to 30℃. In the embodiments and comparative examples of this invention, the room temperature drying temperature is set to 25℃.

[0097] Performance testing

[0098] Membrane surface wettability determination: The surface hydrophilicity and hydrophobicity of the GO / HOF composite membrane were determined by a contact angle meter. During the measurement, the sample was first fixed on a glass slide with double-sided tape, and then placed directly below a microsyringe with a droplet volume of 5.0 μL. After the droplet stabilized on the sample surface, the instrument's built-in camera was used to take a picture and record the value. The contact angle value was calculated using the TrueDrop method. Each sample was measured three times and the average value was taken.

[0099] Membrane surface morphology characterization method: The surface morphology of the membrane was characterized by scanning electron microscopy (SEM, LEO1530vp, 5kV). Small pieces of GO / HOF composite membrane were cut out and attached to conductive adhesive without violently compressing the membrane surface. After being sputtered with gold for 45s, the membrane was observed under a scanning electron microscope. The voltage was 3.0kV.

[0100] Membrane flux determination method: The flux of the prepared membrane was tested using a standard dead-end filtration apparatus equipped with a nitrogen cylinder, a digital balance, and a computer. The mass of the filtrate at different times was recorded by an electronic balance connected to the computer. The flux was calculated using the following formula (1):

[0101] In the formula, A is the effective membrane area (m²). 2 V is the permeate volume (L), t is the permeate time (h), and P is the permeate pressure (bar).

[0102] Membrane rejection rate determination method: The membrane rejection performance was measured by filtering a 5 ppm micro-contaminant solution. Using the aforementioned flux measurement apparatus, the concentrations of micro-contaminants before and after filtration were determined by a UV-Vis spectrophotometer. The rejection rate was calculated using the following formula:

[0103] In the formula, R is the rejection rate, and C0 and C1 are the concentrations of micro-pollutants before and after filtration, respectively.

[0104] The GO / HOF composite membranes obtained in the embodiments of the present invention were characterized for wettability, membrane surface morphology, etc.

[0105] The GO membrane obtained in Comparative Example 1 was structurally characterized and applied to the removal of dye molecules and micro-pollutants.

[0106] The HOF membrane obtained in Comparative Example 2 was structurally characterized, and its scanning electron microscope image is shown in Figure 5.

[0107] The GO / HOF composite membrane obtained in the embodiments of the present invention was applied to the retention of common micro-pollutants such as Coomassie Brilliant Blue (BBG), Congo Red (CR), Crystal Violet (CV), Rhodamine B (RhB), Orange-Yellow G (OY-G), and Bisphenol A (BPA).

[0108] Based on the analysis of Figures 1 to 4, as shown in Figure 1, the flux of the GO / HOF-400 composite membrane for the dye BBG is 22.27 L·m. -2 ·h -1 ·bar -1 The rejection rate is 100%. As shown in Figure 2, the GO / HOF-400 composite membrane has a large and uniform HOF content on its surface, with a small amount of GO adhering to it. As shown in Figure 3, the water contact angle of the GO / HOF-400 composite membrane is 58°, indicating good hydrophilicity. As shown in Figure 4, the GO / HOF-400 composite membrane exhibits good retention effects on common dye pollutants and micro-pollutants such as Coomassie Brilliant Blue, Congo Red, Crystal Violet, Rhodamine B, Orange G, and Bisphenol A.

[0109] As shown in Figure 2, compared to the GO / HOF-400 composite membrane in Example 1, the GO / HOF-200 composite membrane in Example 2 has a lower HOF loading and a slightly more hydrophilic surface. When applied to the removal of BBG dye molecules, it showed a flux of 13.12 L·m⁻¹. -2 ·h -1 ·bar -1 The rejection rate is close to 100%. Compared with Example 1, the GO / HOF-200 composite membrane uses less HOF and has fewer HOF intercalations between GO layers, resulting in a lower flux. Compared with the GO membrane in Comparative Example 1, the GO / HOF-200 composite membrane in Example 2 has a slightly higher rejection rate.

[0110] As shown in Figure 2, compared to the GO / HOF-400 composite membrane in Example 1, the GO / HOF-800 composite membrane in Example 3 has a higher HOF loading and a more hydrophobic surface. When applied to the removal of BBG dye molecules, it showed a flux of 18.35 L·m⁻¹. -2 ·h -1 ·bar-1 The retention rate is close to 100%. Compared with Example 1, the excessive HOF in the GO / HOF-800 composite membrane will block the water transport channels between the GO layers, resulting in a decrease in flux.

[0111] Compared to the GO / HOF-400 composite membrane in Example 1, the pure GO membrane in Comparative Example 1 has a smooth and dense surface, which is not conducive to the transmission of water, and therefore has a lower flux.

[0112] Compared to the GO / HOF-400 composite membrane in Example 1, the HOF nanorods on the surface of the pure HOF membrane in Comparative Example 2 are dispersed on the surface of the substrate membrane, with large intercrystalline voids, and cannot form a dense membrane structure.

[0113] As shown in Figure 2, compared to the GO membrane in Comparative Example 1, the GO / HOF-50 composite membrane in Example 4 has only a very small amount of HOF loading, and the change in membrane surface morphology is not significant. Figure 3 shows that the water contact angle on the surface of the GO / HOF-50 composite membrane is slightly increased due to the presence of hydrophobic HOF. Meanwhile, in the BBG dye molecule retention performance test, the flux is shown to be 7.73 L·m⁻¹. -2 ·h -1 ·bar -1 The retention rate remained at 100%, indicating that the enhanced hydrophobicity of the membrane resulted in a small flux, but the excellent retention performance of the original GO membrane was retained.

[0114] The hydrogen-bonded organic framework composite membrane provided in this invention combines the high specific surface area of ​​hydrogen-bonded organic framework materials with the excellent mechanical properties and chemical stability of graphene oxide materials, showing good application prospects in the field of water treatment. This hydrogen-bonded organic framework composite membrane can be used for the interception and removal of organic micropollutants in wastewater.

[0115] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a hydrogen-bonded organic framework composite film, characterized in that, The preparation method includes: The hydrogen-bonded organic framework material is dissolved in the first solvent to obtain a hydrogen-bonded organic framework material solution; Graphene oxide is dissolved in a second solvent to obtain a graphene oxide solution; The hydrogen-bonded organic framework material solution and the graphene oxide solution were mixed and brought to a constant volume, and then subjected to ultrasonic treatment to obtain a uniformly mixed GO / HOF composite solution. The GO / HOF composite solution was filtered onto the surface of the substrate membrane using a vacuum filtration method, and a composite membrane with a uniform structure was formed by utilizing the hydrogen bonding and π-π conjugation between the hydrogen-bonded organic framework and graphene oxide.

2. The method for preparing the hydrogen-bonded organic framework composite film as described in claim 1, characterized in that, The hydrogen-bonded organic framework material is prepared by dissolving 5,10,15,20-tetra(4-carboxyphenyl)porphyrin monomer in a mixed solvent of N,N-dimethylacetamide and methanol, and then reacting the solvent through an evaporation reaction.

3. The method for preparing the hydrogen-bonded organic framework composite film as described in claim 2, characterized in that, The solvent evaporation reaction is carried out at a temperature of 50℃ to 70℃ for a time of 20h to 30h.

4. The method for preparing the hydrogen-bonded organic framework composite film as described in claim 1, characterized in that, In the GO / HOF composite solution, the mass ratio of graphene oxide to the hydrogen-bonded organic framework material is 1:2 to 8.

5. The method for preparing the hydrogen-bonded organic framework composite film as described in claim 1, characterized in that, The total volume of the GO / HOF complex solution is 10 mL to 40 mL.

6. The method for preparing the hydrogen-bonded organic framework composite film as described in claim 1, characterized in that, The ultrasonic treatment has an ultrasonic frequency of 30kHz to 40kHz, an ultrasonic time of 10min to 20min, and an ultrasonic treatment volume of 10mL to 40mL.

7. The method for preparing the hydrogen-bonded organic framework composite film as described in claim 1, characterized in that, The first solvent and the second solvent are each independently selected from one of methanol, ethanol, and deionized water.

8. The method for preparing the hydrogen-bonded organic framework composite film as described in claim 1, characterized in that, The base membrane is selected from one of cellulose acetate membrane, nylon membrane, and polytetrafluoroethylene membrane.

9. A hydrogen-bonded organic framework material composite membrane, characterized in that, The hydrogen-bonded organic framework material composite film is prepared by the method for preparing hydrogen-bonded organic framework material composite film according to any one of claims 1-8, and the hydrogen-bonded organic framework material composite film is formed by constructing a composite of hydrogen-bonded organic framework material and graphene oxide.

10. The application of a hydrogen-bonded organic framework composite membrane as described in claim 9, or a hydrogen-bonded organic framework composite membrane prepared by the preparation method of any one of claims 1-8, in water purification.

Images