GO (at) TP-TTTA composite nanofiltration membrane as well as preparation method and application thereof

Abstract

The invention relates to the technical field of membrane separation, and particularly provides a GO-coated TP-TTTA composite nanofiltration membrane and a preparation method and application thereof.The GO-coated TP-TTTA composite nanofiltration membrane comprises a basement membrane and a graphene oxide membrane formed on the surface of one side of the basement membrane, a porous organic framework material is grown between film layers of the graphene oxide film and on the surface of the graphene oxide film in situ, and the porous organic framework material is a TP-TTTA material obtained by bonding 2, 4, 6-tri (4-aminophenyl)-1, 3, 5-triazine and trialdehyde phloroglucinol through a carbon-carbon double bond. The GO-coated TP-TTTA composite nanofiltration membrane provided by the invention has excellent stability and permeability, the preparation method is simple to operate, and the reaction conditions are low-carbon and environment-friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane separation, and in particular to a GO@TP-TTTA composite nanofiltration membrane and a preparation method and application thereof. Background Art

[0002] Two-dimensional (2D) layered membranes have attracted widespread attention in the removal of micropollutants due to their unique transmission channel structure. Among them, graphene oxide (GO) membranes, as a typical two-dimensional material, have been highly valued by academia and industry due to their excellent performance. However, GO membranes still face two key challenges in practical applications: one is its stability and membrane fouling problems in complex waste liquid solution environments; the other is the defects in the membrane caused by the irregular stacking of GO nanosheets, which will reduce the molecular selectivity of the GO membrane. These challenges are closely related to the microscopic framework structure of GO and are the core bottlenecks that limit its practical application.

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

[0004] The main purpose of the present invention is to propose a GO@TP-TTTA composite nanofiltration membrane and its preparation method and application. The GO@TP-TTTA composite nanofiltration membrane in the present invention has excellent stability and permeability, and its preparation method is simple to operate, and the reaction conditions are low-carbon and environmentally friendly.

[0005] The first aspect of the present invention provides a GO@TP-TTTA composite nanofiltration membrane, which includes a base membrane and a graphene oxide membrane formed on the surface of one side of the base membrane, wherein a porous organic framework material is in situ grown between membrane layers of the graphene oxide membrane and on the surface of the graphene oxide membrane, and the porous organic framework material is a TP-TTTA material obtained by bonding 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and trialdehyde pyroglycol through carbon-carbon double bonds.

[0006] In some embodiments of the present invention, the 2,4,6-tris(4-aminophenyl)-1,3,5-triazine grows between film layers and on the surface of the graphene oxide film through amide bonds.

[0007] In some embodiments of the present invention, the base membrane is selected from a cellulose acetate membrane, a nylon membrane, and a polytetrafluoroethylene membrane.

[0008] In some embodiments of the present invention, the pore size of the basement membrane is 0.22 μm to 0.40 μm.

[0009] The second aspect of the present invention provides a method for preparing the GO@TP-TTTA composite nanofiltration membrane described in the first aspect, and the preparation method of the GO@TP-TTTA composite nanofiltration membrane comprises: dissolving graphene oxide and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine in deionized water respectively to prepare a graphene oxide solution and a TTTA solution; dissolving trialdehyde phloroglucinol in an acetic acid solution to prepare a TP-acetic acid solution; passing a mixed solution of the graphene oxide solution and the TTTA solution through a substrate membrane by vacuum filtration to obtain a GO@TTTA seed membrane; immersing the GO@TTTA seed membrane in the TP-acetic acid solution, and performing in-situ growth at room temperature to obtain the GO@TP-TTTA composite nanofiltration membrane.

[0010] In some embodiments of the present invention, in the mixed solution, the mass ratio of the graphene oxide to the TTTA is 1:(5-10).

[0011] In some embodiments of the present invention, in the in-situ growth, the mass ratio of the graphene oxide to the TP is 1:60-80.

[0012] In some embodiments of the present invention, the TP-acetic acid solution and the TTTA solution are prepared by ultrasonic dispersion treatment respectively, and the ultrasonic dispersion treatment time in the preparation of the TTTA solution is 25 min to 30 min; the ultrasonic dispersion treatment time in the preparation of the TP-acetic acid solution is 25 min to 30 min.

[0013] In some embodiments of the present invention, the graphene oxide solution and the TTTA solution are mixed and then ultrasonically treated for 5 min to 10 min to obtain the mixed solution; the vacuum degree of the vacuum filtration is 1 bar to 2 bar.

[0014] The third aspect of the present invention provides an application of the GO@TP-TTTA composite nanofiltration membrane described in the first aspect or the GO@TP-TTTA composite nanofiltration membrane prepared by the preparation method of the GO@TP-TTTA composite nanofiltration membrane described in the second aspect in water purification.

[0015] Beneficial effects of the present invention: 1. The present invention in situ grows a porous organic framework material TP-TTTA on a graphene oxide membrane, modifies the edges of GO sheets in the GO membrane and increases the interlayer spacing of the GO membrane, thereby improving the permeability of the GO membrane without reducing the molecular separation performance of the GO membrane.

[0016] 2. The GO@TP-TTTA composite nanofiltration membrane provided by the present invention is prepared by vacuum filtration and in-situ growth. The preparation process of the composite nanofiltration membrane is simple, does not require organic solvents, is low-cost, is green and environmentally friendly, and can be applied to large-scale industrial production.

[0017] 3. The GO@TP-TTTA composite nanofiltration membrane provided by the present invention has high permeability, stability and excellent molecular separation performance.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those skilled in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only used for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. In the accompanying drawings: Figure 1 is a process flow chart of a method for preparing a GO@TP-TTTA composite nanofiltration membrane according to one or more embodiments; Figure 2 The scanning electron microscope images of the GO@TP-TTTA-1000 composite nanofiltration membrane in Example 2 of the present invention and the GO composite nanofiltration membrane in Comparative Example 1 are shown; wherein, Figure 2 A in FIG. 1 is a surface image of the GO composite nanofiltration membrane prepared in Comparative Example 1; Figure 2 B is the surface image of the GO@TP-TTTA-1000 composite nanofiltration membrane prepared in Example 2; Figure 2 C in the figure is a cross-sectional image of the GO composite nanofiltration membrane prepared in Comparative Example 1; Figure 2 D in FIG. 1 is a cross-sectional image of the GO@TP-TTTA-1000 composite nanofiltration membrane prepared in Example 2; Figure 3 Graphs showing pure water flux and water contact angle of composite nanofiltration membranes in the embodiments of the present invention and comparative examples; wherein, Figure 3 (a) is the water flux of the GO@TP-TTTA-500 and GO@TP-TTTA-1000 composite nanofiltration membranes prepared in Examples 1 to 2 and the GO composite nanofiltration membrane and GO@TP-TTTA-2000 composite nanofiltration membrane prepared in Comparative Examples 1 and 2; Figure 3 (b) is the water contact angle of the GO@TP-TTTA-500 and GO@TP-TTTA-1000 composite nanofiltration membranes prepared in Examples 1 to 2 and the GO composite nanofiltration membrane and GO@TP-TTTA-2000 composite nanofiltration membrane prepared in Comparative Examples 1 and 2; Figure 4 The retention performance of the GO@TP-TTTA-500 and GO@TP-TTTA-1000 composite nanofiltration membranes prepared in Examples 1 to 2 of the present invention and the GO composite nanofiltration membrane and GO@TP-TTTA-2000 composite nanofiltration membrane prepared in Comparative Examples 1 and 2 for Coomassie Brilliant Blue (BBG); Figure 5 It is the flux recovery rate of the GO composite nanofiltration membrane prepared in Comparative Example 1 of the present invention and the GO@TP-TTTA-1000 composite nanofiltration membrane prepared in Example 2. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the specification and claims of the present invention and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0022] In the description of the embodiments of the present invention, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present invention, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0023] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0024] In the description of the embodiments of the present invention, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0025] In the description of the embodiments of the present invention, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0026] The feasibility of graphene oxide (GO) membranes in practical applications still faces two key challenges: one is its stability in complex waste liquid solutions; the other is the defects in the membrane caused by irregular stacking of GO nanosheets, which will reduce the molecular selectivity of the GO membrane. These challenges are closely related to the microscopic framework structure of GO and are the core technical bottlenecks that limit its practical application.

[0027] The present invention provides a Figure 2 The GO@TP-TTTA composite nanofiltration membrane shown includes a base membrane and a graphene oxide membrane formed on the surface of one side of the base membrane, and a porous organic framework material is in situ grown between the membrane layers of the graphene oxide membrane and on the surface of the graphene oxide membrane, wherein the porous organic framework material is a TP-TTTA material obtained by bonding 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TTTA) and trialdehyde pyroglycol (TP) through a carbon-carbon double bond.

[0028] In an embodiment of the present invention, by in-situ growing TP-TTTA between GO layers and at edge defects, the GO skeleton structure is effectively stabilized and the stability of the membrane is significantly improved. In addition, the permeability of the membrane is significantly enhanced by optimizing the water molecule transmission channel.

[0029] In an embodiment of the present invention, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is connected to the interlayer and surface of the graphene oxide film through an amide bond, thereby achieving in-situ growth of the TP-TTTA material.

[0030] In some embodiments of the present invention, the substrate membrane is selected from a cellulose acetate membrane, a nylon membrane, and a polytetrafluoroethylene membrane.

[0031] In some embodiments of the present invention, the pore size of the basement membrane is 0.22 μm to 0.40 μm. For example, the pore size of the basement membrane can be 0.22 μm, 0.23 μm, 0.24 μm, 0.25 μm, 0.26 μm, 0.27 μm, 0.28 μm, 0.29 μm, 0.30 μm, 0.31 μm, 0.32 μm, 0.33 μm, 0.34 μm, 0.35 μm, 0.36 μm, 0.37 μm, 0.38 μm, 0.39 μm, 0.40 μm or any value within the above range.

[0032] The present invention also provides a method for preparing a GO@TP-TTTA composite nanofiltration membrane, the key of which is to grow the TP-TTTA material in situ on the GO membrane.

[0033] In an embodiment of the present invention, graphene oxide and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine are respectively dissolved in deionized water to prepare graphene oxide solution and TTTA solution; trialdehyde pyrogallol is dissolved in acetic acid solution to prepare TP-acetic acid solution; a mixed solution of graphene oxide solution and TTTA solution is passed through a substrate membrane by vacuum filtration to obtain a GO@TTTA seed membrane; the GO@TTTA seed membrane is immersed in TP-acetic acid solution and in situ grown at room temperature to obtain a GO@TP-TTTA composite nanofiltration membrane.

[0034] Figure 1 A flow chart of the preparation method of the GO@TP-TTTA composite nanofiltration membrane is shown, which is specifically carried out according to the following steps.

[0035] Preparation of TTTA solution In an embodiment of the present invention, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is dissolved in deionized water to prepare a TTTA solution.

[0036] In some embodiments of the present invention, ultrasonic dispersion treatment is used in the preparation of the TTTA solution, and the time of ultrasonic dispersion treatment is 25 min to 30 min. Exemplarily, the time of ultrasonic dispersion treatment in the preparation of the TTTA solution can be one of 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, or any value satisfying the above range.

[0037] As an embodiment of the present invention, 28.36 mg of TTTA was weighed and then dissolved in 28.36 mL of deionized water, and then ultrasonically treated for 30 min to obtain a uniformly dispersed TTTA solution.

[0038] Preparation of TP-acetic acid solution In an embodiment of the present invention, trialdehyde phloroglucinol is dissolved in an acetic acid solution to prepare a TP-acetic acid solution.

[0039] In an embodiment of the present invention, ultrasonic dispersion treatment is used in the preparation of TP-acetic acid solution, and the time of ultrasonic dispersion treatment is 25 min to 30 min. Exemplarily, the time of ultrasonic dispersion treatment in the preparation of TP-acetic acid solution can be one of 25 min, 26 min, 27 min, 28 min, 29 min, 30 min or any value satisfying the above range.

[0040] As an embodiment of the present invention, 33.64 mg of TP was weighed and dissolved in 32 mL of deionized water, and then 1.64 mL of glacial acetic acid (17.5 mol) was added, and ultrasonicated for 30 min to obtain a uniformly dispersed TP-acetic acid solution.

[0041] Preparation of graphene oxide solution In an embodiment of the present invention, graphene oxide (GO) is dissolved in deionized water to prepare a graphene oxide solution.

[0042] In some embodiments of the present invention, ultrasonic dispersion treatment is used in the preparation of graphene oxide solution, and the time of ultrasonic dispersion treatment is 25 min to 30 min. Exemplarily, the time of ultrasonic dispersion treatment in the preparation of graphene oxide solution can be one of 25 min, 26 min, 27 min, 28 min, 29 min, 30 min or any value satisfying the above range.

[0043] As an embodiment of the present invention, 100 μg of graphene oxide was weighed and then dissolved in 30 mL of deionized water, and then ultrasonically treated for 30 min to obtain a uniformly dispersed graphene oxide solution.

[0044] Preparation of graphene oxide / TTTA mixed solution In an embodiment of the present invention, a TTTA solution is added to a graphene oxide solution to obtain a uniformly mixed graphene oxide / TTTA mixed solution.

[0045] In an embodiment of the present invention, a TTTA solution is added to a graphene oxide solution, and ultrasonic treatment is performed to obtain a uniformly dispersed graphene oxide / TTTA mixed solution.

[0046] In some embodiments of the present invention, the ultrasonic treatment time is 5 min to 10 min. Exemplarily, the ultrasonic treatment time can be one of 5 min, 6 min, 7 min, 8 min, 9 min, 10 min or any value satisfying the above range.

[0047] In some embodiments of the present invention, in the graphene oxide / TTTA mixed solution, the mass ratio of graphene oxide to TTTA is 1:(5-10). Exemplarily, the mass ratio of graphene oxide to TTTA can be one of 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or any value satisfying the above range.

[0048] Vacuum filtration In an embodiment of the present invention, a graphene oxide / TTTA mixed solution is filtered onto the surface of a substrate film by vacuum filtration to prepare a GO@TTTA seed film.

[0049] In some embodiments of the present invention, the vacuum degree of vacuum filtration is 1 bar to 2 bar. Exemplarily, the vacuum degree can be one of 1 bar and 2 bar or any value satisfying the above range.

[0050] It is worth mentioning that in order to avoid the GO@TTTA seed film from breaking during the subsequent immersion process, the GO@TTTA seed film can be properly dried before in-situ growth to improve the stability of the film. The drying temperature provided in the embodiment of the present invention can be 50°C~60°C, and the drying time can be 4 min~6 min. Exemplarily, the drying temperature can be one of 50°C, 55°C, 60°C or any value that satisfies the above range. The drying time can be one of 4 min, 5 min, 6 min or any value that satisfies the above range.

[0051] In situ growth In an embodiment of the present invention, a GO@TTTA seed membrane is immersed in a TP-acetic acid solution by an in-situ growth method to prepare a GO@TP-TTTA composite nanofiltration membrane.

[0052] In some embodiments of the present invention, in the in-situ growth, the mass ratio of graphene oxide to TP is 1:60 to 80. For example, the mass ratio of graphene oxide to TP can be one of 1:60, 1:65, 1:70, 1:75, 1:80 or any value satisfying the above range.

[0053] In some embodiments of the present invention, during in-situ growth, the immersion time or in-situ growth time of the GO@TTTA seed film may be 2 h to 3 h, not less than 2 h. Exemplarily, the in-situ growth time may be 2 h, 3 h, or any value satisfying the above range.

[0054] The present invention also provides an application of the GO@TP-TTTA composite nanofiltration membrane or the GO@TP-TTTA composite nanofiltration membrane prepared by the above preparation method, which can be used in water purification, for example.

[0055] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the amounts of the experimental reagents, unless otherwise specified, are the amounts of reagents used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0056] Example 1 Reference Figure 1 The preparation process shown is used to prepare GO@TP-TTTA composite nanofiltration membrane.

[0057] (1) Weigh 28.36 mg of TTTA and dissolve it in 28.36 mL of deionized water. After ultrasonic treatment for 30 min, a uniformly dispersed TTTA solution was obtained.

[0058] (2) Weigh 33.64 mg of TP and dissolve it in 32 mL of deionized water. Then add 1.64 mL of glacial acetic acid (17.5 mol) and ultrasonicate for 30 min to obtain a uniformly dispersed TP-acetic acid solution.

[0059] (3) Weigh 100 μg of graphene oxide (GO) and dissolve it in 30 mL of deionized water. After ultrasonic treatment for 30 min, a uniformly dispersed graphene oxide solution was obtained.

[0060] (4) Weigh 500 μg of the TTTA aqueous solution obtained in step (1) and 100 μg of the graphene oxide solution obtained in step (3), mix them and ultrasonically treat them for 5 min to obtain a uniformly mixed GO@TTTA-500 mixed solution.

[0061] (5) The GO@TTTA-500 mixed solution obtained in step (4) was filtered onto the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. After the filtration was completed, the formed GO@TTTA-500 seed membrane was transferred to an oven for drying at a drying temperature of 60 °C for 5 min.

[0062] (6) The dried GO@TTTA-500 seed membrane obtained in step (5) was transferred and immersed in the TP-acetic acid solution obtained in step (2) for 2 h of in situ growth. After the growth was completed, the formed GO@TP-TTTA-500 composite nanofiltration membrane was stored in deionized water.

[0063] Example 2 Reference Figure 1 The preparation process shown is used to prepare GO@TP-TTTA composite nanofiltration membrane.

[0064] (1) Weigh 28.36 mg of TTTA and dissolve it in 28.36 mL of deionized water. After ultrasonic treatment for 30 min, a uniformly dispersed TTTA solution was obtained.

[0065] (2) Weigh 33.64 mg of TP and dissolve it in 32 mL of deionized water. Then add 1.64 mL of glacial acetic acid (17.5 mol) and ultrasonicate for 30 min to obtain a uniformly dispersed TP / acetic acid solution.

[0066] (3) Weigh 100 μg of graphene oxide (GO) and dissolve it in 30 mL of deionized water. After ultrasonic treatment for 30 min, a uniformly dispersed graphene oxide solution was obtained.

[0067] (4) Take 1000 μg of the TTTA aqueous solution obtained in step (1) and 100 μg of the graphene oxide solution obtained in step (3), mix them and ultrasonically treat them for 5 min to obtain a uniformly mixed GO@TTTA-1000 mixed solution.

[0068] (5) The GO@TTTA-1000 mixed solution obtained in step (4) was filtered onto the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. After the filtration was completed, the formed GO@TTTA-1000 seed membrane was transferred to an oven for drying at a drying temperature of 60 °C for 5 min.

[0069] (6) The dried GO@TTTA-1000 seed membrane obtained in step (5) was transferred and immersed in the TP-acetic acid solution obtained in step (2) for 2 h of in-situ growth. After the growth was completed, the formed GO@TP-TTTA-1000 composite nanofiltration membrane was stored in deionized water.

[0070] Comparative Example 1 Preparation of GO nanofiltration membrane.

[0071] (1) Weigh 33.64 mg of TP and dissolve it in 32 mL of deionized water. Then add 1.64 mL of glacial acetic acid (17.5 mol) and ultrasonicate for 30 min to obtain a uniformly dispersed TP-acetic acid solution.

[0072] (2) Take 100 μg of graphene oxide (GO) and add it to 30 mL of water and ultrasonicate it for 5 min to mix it evenly to obtain a uniform GO solution.

[0073] (3) The GO solution obtained in step (2) was filtered onto the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. After the filtration was completed, the formed GO membrane was transferred to an oven for drying at a temperature of 60°C for 5 min.

[0074] (4) The dried GO membrane obtained in step (3) was transferred and immersed in the TP-acetic acid solution obtained in step (1) for 2 h of in-situ growth. After the growth was completed, the formed GO composite nanofiltration membrane was stored in deionized water.

[0075] Comparative Example 2 Reference Figure 1 The preparation process shown is used to prepare GO@TP-TTTA composite nanofiltration membrane.

[0076] (1) Weigh 28.36 mg of TTTA and dissolve it in 28.36 mL of deionized water. After ultrasonic treatment for 30 min, a uniformly dispersed TTTA solution was obtained.

[0077] (2) Weigh 33.64 mg of TP and dissolve it in 32 mL of deionized water. Then add 1.64 mL of glacial acetic acid (17.5 mol) and ultrasonicate for 30 min to obtain a uniformly dispersed TP-acetic acid solution.

[0078] (3) Weigh 100 μg of graphene oxide (GO) and dissolve it in 30 mL of deionized water. After ultrasonic treatment for 30 min, a uniformly dispersed graphene oxide solution was obtained.

[0079] (4) Take 2000 μg of the TTTA aqueous solution obtained in step (1) and 100 μg of the graphene oxide solution obtained in step (3), mix them and ultrasonically treat them for 5 min to obtain a uniformly mixed GO@TTTA-2000 mixed solution.

[0080] (5) The GO@TTTA-2000 mixed solution obtained in step (4) was filtered onto the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. After the filtration was completed, the formed GO@TTTA-2000 seed membrane was transferred to an oven for drying at a drying temperature of 60 °C for 5 min.

[0081] (6) The dried GO@TTTA-2000 seed membrane obtained in step (5) was transferred and immersed in the TP-acetic acid solution obtained in step (2) for 2 h of in-situ growth. After the growth was completed, the formed GO@TP-TTTA-2000 composite nanofiltration membrane was stored in deionized water.

[0082] Performance Testing The GO@TP-TTTA-500 and GO@TP-TTTA-1000 composite nanofiltration membranes prepared in Examples 1 to 2 and the GO composite nanofiltration membranes and GO@TP-TTTA-2000 composite nanofiltration membranes prepared in Comparative Examples 1 to 2 were characterized by membrane surface and cross-sectional morphology, wetting properties, etc., and the pure water flux and the retention of dye molecules were detected and analyzed. The results are as follows: Figures 2 to 4 shown.

[0083] The water permeability of the prepared membrane was evaluated using standard terminal filtration equipment, including a nitrogen bottle, a digital balance, an ultrafiltration cup (MSC-50, MOSU China Co., Ltd.), and a computer. The quality of the filtrate was monitored using a digital balance at a pressure of 1.0 bar. The water flux was calculated using formula (1).

[0084] (1) In formula (1), J is the water flux (L m −2 ·h −1 bar −1 ), A is the effective membrane area (m 2 ), V is the filtrate volume (L), t is the filtration time (h), and P is the applied pressure (bar).

[0085] In the present invention, the retention capacity of each membrane was tested by filtering a 20 ppm dye solution. All samples were measured at least three times. The dye concentration in the feed and filtrate was analyzed using a UV-visible spectrophotometer. The retention rate was calculated according to formula (2).

[0086] (2) In formula (2), R is the interception rate, C 0 and C 1 are the dye concentrations before and after filtration, respectively.

[0087] Combination Figure 2 A and Figure 2 As shown in Figure 1, due to the introduction of TTTA, a rough porous structure appears on the surface of the GO@TP-TTTA-1000 composite nanofiltration membrane.

[0088] Combination Figure 2 C and Figure 2 As shown in Figure 5D, due to the introduction of TTTA, nanomaterials appear between the layers of the GO@TP-TTTA-1000 composite nanofiltration membrane and the interlayer spacing increases.

[0089] Combination Figure 3 (a) and Figure 3As shown in (b), with the increase of TTTA content, the permeability of GO@TP-TTTA composite nanofiltration membrane gradually increased, and the surface water contact angle of GO@TP-TTTA composite nanofiltration membrane gradually decreased. The pure water flux of GO composite nanofiltration membrane was 105.6 L·m -2 ·h -1 bar -1 , while the pure water flux of GO@TP-TTTA-1000 composite nanofiltration membrane increased to 276.3 L·m -2 ·h -1 bar -1 .

[0090] The GO@TP-TTTA-500 and GO@TP-TTTA-1000 composite nanofiltration membranes prepared in Examples 1 to 2 and the GO composite nanofiltration membranes and GO@TP-TTTA-2000 composite nanofiltration membranes prepared in Comparative Examples 1 and 2 were tested for separation performance and applied to the filtration separation of Coomassie Brilliant Blue (BBG).

[0091] like Figure 4 As shown, the retention rate of BBG by GO composite nanofiltration membrane in Comparative Example 1 is 99%, the retention rate of BBG by GO@TP-TTTA-500 composite nanofiltration membrane in Example 1 is 99.0%, the retention rate of BBG by GO@TP-TTTA-1000 composite nanofiltration membrane in Example 2 is 98.3%, and the retention rate of BBG by GO@TP-TTTA-2000 composite nanofiltration membrane in Comparative Example 2 is 79.1%.

[0092] In addition, the GO@TP-TTTA-1000 composite nanofiltration membrane prepared in Example 2 and the GO composite nanofiltration membrane prepared in the comparative example were tested for their anti-pollution performance of BBG.

[0093] like Figure 5 As shown, the flux recovery rate of the GO composite nanofiltration membrane in Comparative Example 1 is 78%, and the flux recovery rate of the GO@TP-TTTA-1000 composite nanofiltration membrane in Example 2 is 93%.

[0094] In summary, the GO@TP-TTTA composite nanofiltration membrane provided by the present invention has three functions of high permeability, excellent molecular separation and anti-fouling.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A GO@TP-TTTA composite nanofiltration membrane, characterized in that: The invention comprises a base film and a graphene oxide film formed on the surface of one side of the base film, wherein a porous organic framework material is in-situ grown between film layers of the graphene oxide film and on the surface of the graphene oxide film, and the porous organic framework material is a TP-TTTA material obtained by bonding 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and trialdehyde phloroglucinol through carbon-carbon double bonds.

2. The GO@TP-TTTA composite nanofiltration membrane according to claim 1, characterized in that The 2,4,6-tris(4-aminophenyl)-1,3,5-triazine grows between film layers and on the surface of the graphene oxide film through amide bonds.

3. The GO@TP-TTTA composite nanofiltration membrane according to claim 1, characterized in that The base film is selected from one of cellulose acetate film, nylon film and polytetrafluoroethylene film.

4. The GO@TP-TTTA composite nanofiltration membrane according to claim 1, characterized in that The pore size of the basement membrane is 0.22 μm to 0.40 μm.

5. A method for preparing the GO@TP-TTTA composite nanofiltration membrane according to any one of claims 1 to 4, characterized in that: The preparation method of the GO@TP-TTTA composite nanofiltration membrane comprises: Dissolving graphene oxide and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine in deionized water respectively to prepare a graphene oxide solution and a TTTA solution; Dissolving trialdehyde phloroglucinol in acetic acid solution to prepare TP-acetic acid solution; The mixed solution of graphene oxide solution and TTTA solution was passed through the substrate membrane by vacuum filtration to obtain a GO@TTTA seed membrane; The GO@TTTA seed membrane is immersed in the TP-acetic acid solution and in-situ grown at room temperature to obtain the GO@TP-TTTA composite nanofiltration membrane.

6. The method for preparing the GO@TP-TTTA composite nanofiltration membrane according to claim 5, characterized in that: In the mixed solution, the mass ratio of the graphene oxide to the TTTA is 1:(5-10).

7. The method for preparing the GO@TP-TTTA composite nanofiltration membrane according to claim 5, characterized in that: In the in-situ growth, the mass ratio of the graphene oxide to the TP is 1:60-80.

8. The method for preparing the GO@TP-TTTA composite nanofiltration membrane according to claim 5, characterized in that: The TP-acetic acid solution and the TTTA solution are prepared by ultrasonic dispersion treatment respectively. The ultrasonic dispersion treatment time in the preparation of the TTTA solution is 25 min to 30 min; The ultrasonic dispersion treatment time in the preparation of the TP-acetic acid solution is 25 min to 30 min.

9. The method for preparing the GO@TP-TTTA composite nanofiltration membrane according to claim 5, characterized in that: The graphene oxide solution and the TTTA solution are mixed and then subjected to ultrasonic treatment for 5 min to 10 min to obtain the mixed solution; The vacuum degree of the vacuum filtration is 1 bar to 2 bar.

10. Use of the GO@TP-TTTA composite nanofiltration membrane according to claims 1 to 4 or the GO@TP-TTTA composite nanofiltration membrane prepared by the preparation method of the GO@TP-TTTA composite nanofiltration membrane according to any one of claims 5 to 9 in water purification.

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