GO@TP-TTTA Composite Nanofiltration Membrane and Its Preparation Method and Application

Abstract

The present invention relates to the technical field of membrane separation, and specifically provides a GO@TP-TTTA composite nanofiltration membrane, a preparation method thereof and an application thereof. The GO@TP-TTTA composite nanofiltration membrane comprises a substrate membrane and a graphene oxide membrane formed on one surface of the substrate membrane. Porous organic framework materials are in-situ grown between the membrane layers of the graphene oxide membrane and on the surface of the graphene oxide membrane. The porous organic framework material is a TP-TTTA material obtained by bonding 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and phloroglucinol trialdehyde through carbon-carbon double bonds. The GO@TP-TTTA composite nanofiltration membrane in the present invention has excellent stability and permeability performance, and its preparation method is simple to operate and has low-carbon and environmentally friendly reaction conditions.

Description

Technical Field

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

[0002] Two-dimensional (2D) layered membranes have attracted extensive attention in removing micro-pollutants due to their unique transport channel structures. Among them, graphene oxide (GO) membranes, as a typical two-dimensional material, have received great attention from academia and industry due to their excellent properties. However, GO membranes still face two key challenges in practical applications: one is their stability and membrane fouling problems in complex waste liquid solution environments; the other is the defects inside the membrane caused by the irregular stacking of GO nanosheets, which will reduce the molecular selectivity of GO membranes. These challenges are closely related to the microscopic framework structure of GO and are the core bottlenecks restricting its practical application.

[0003] Therefore, in view of the above deficiencies, the present invention is specifically proposed. Summary of the Invention

[0004] The main object of the present invention is to provide a GO@TP-TTTA composite nanofiltration membrane, a preparation method thereof, and an application thereof. The GO@TP-TTTA composite nanofiltration membrane in the present invention has excellent stability and permeability performance, 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 substrate membrane and a graphene oxide membrane formed on one surface of the substrate membrane. A porous organic framework material grows in situ between the membrane layers of the graphene oxide membrane and on the surface of the graphene oxide membrane. The porous organic framework material is a TP-TTTA material obtained by bonding 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and phloroglucinol trialdehyde 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 the membrane layers and on the surface of the graphene oxide membrane through amide bonds.

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

[0008] In some embodiments of the present invention, the pore size of the substrate 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. The method for preparing the GO@TP-TTTA composite nanofiltration membrane includes: 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 phloroglucinol trialdehyde in acetic acid solution to prepare a TP-acetic acid solution; passing the 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; soaking the GO@TTTA seed membrane in the TP-acetic acid solution and carrying out 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, ultrasonic dispersion treatment is independently adopted in the preparation of the TP-acetic acid solution and the TTTA solution. The time of ultrasonic dispersion treatment in the preparation of the TTTA solution is 25 min - 30 min; the time of ultrasonic dispersion treatment in the preparation of the TP-acetic acid solution is 25 min - 30 min.

[0013] In some embodiments of the present invention, after the graphene oxide solution and the TTTA solution are mixed, ultrasonic treatment is carried out, and the time of ultrasonic treatment is 5 min - 10 min to obtain the mixed solution; the vacuum degree of the vacuum filtration is 1 bar - 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 method for preparing the GO@TP-TTTA composite nanofiltration membrane described in the second aspect in water purification.

[0015] The beneficial effects of the present invention:

[0016] 1. By in-situ growing the porous organic framework material TP-TTTA on the graphene oxide membrane, the present invention modifies the edges of the GO sheets in the GO membrane and increases the layer spacing of the GO membrane, thereby improving the permeability of the GO membrane, and at the same time, without reducing the molecular separation performance of the GO membrane.

[0017] 2. The GO@TP-TTTA composite nanofiltration membrane provided by the present invention is prepared by the synergistic method of vacuum filtration and in-situ growth. The preparation process of the composite nanofiltration membrane is simple, without the need for organic solvents, low in cost, green and environmentally friendly, and can be applied to large-scale industrial production.

[0018] 3. The GO@TP-TTTA composite nanofiltration membrane provided by the present invention has high permeability, stability and excellent molecular separation performance.

[0019] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are specifically listed below. Brief Description of the Drawings

[0020] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. In the drawings:

[0021] Figure 1 is a process flow chart of the preparation method of the GO@TP-TTTA composite nanofiltration membrane according to one or more embodiments;

[0022] Figure 2 is a scanning electron micrograph 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; wherein, Figure 2 A in is the surface image of the GO composite nanofiltration membrane prepared in Comparative Example 1; Figure 2 B in is the surface image of the GO@TP-TTTA-1000 composite nanofiltration membrane prepared in Example 2; Figure 2 C in is the cross-sectional image of the GO composite nanofiltration membrane prepared in Comparative Example 1; Figure 2 D in is the cross-sectional image of the GO@TP-TTTA-1000 composite nanofiltration membrane prepared in Example 2;

[0023] Figure 3 is the pure water flux and water contact angle diagram of the composite nanofiltration membrane in the examples and comparative examples of the present invention; wherein, Figure 3 in (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 3In (b), the water contact angles of the GO@TP-TTTA-500 and GO@TP-TTTA-1000 composite nanofiltration membranes prepared in Examples 1 to 2, the GO composite nanofiltration membrane prepared in Comparative Examples 1 and 2, and the GO@TP-TTTA-2000 composite nanofiltration membrane are shown;

[0024] Figure 4 This shows the rejection 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, the GO composite nanofiltration membrane prepared in Comparative Examples 1 and 2, and the GO@TP-TTTA-2000 composite nanofiltration membrane for Coomassie Brilliant Blue (BBG);

[0025] Figure 5 This shows 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 implementation manners

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled 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" and any variations thereof in the specification and claims of the present invention and the above drawings are intended to cover non-exclusive inclusion.

[0028] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present invention, "a plurality of" means more than two unless otherwise specifically defined.

[0029] Referring to "embodiment" herein means that a specific feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The phrase appears at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0030] In the description of the embodiments of the present invention, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in this text, the character " / " generally represents an "or" relationship between the preceding and following associated objects.

[0031] In the description of the embodiments of the present invention, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple sheets" refers to two or more sheets (including two sheets).

[0032] The feasibility of graphene oxide (GO) membranes in practical applications still faces two key challenges: one is the stability problem in a complex waste liquid solution environment; the other is the defects within 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 technical bottlenecks restricting its practical application.

[0033] The present invention provides a GO@TP-TTTA composite nanofiltration membrane as Figure 2 shown, which includes a substrate membrane and a graphene oxide membrane formed on one surface of the substrate membrane. Porous organic framework materials are in-situ grown between the membrane layers of the graphene oxide membrane and on the surface of the graphene oxide membrane. Among them, 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 phloroglucinol trialdehyde (TP) through carbon-carbon double bonds.

[0034] In the embodiments of the present invention, by in-situ growing TP-TTTA between the GO layers and at the edge defects, the GO skeleton structure is effectively stabilized, the stability of the membrane is significantly improved, and the permeation performance of the membrane is significantly enhanced by optimizing the water molecule transport channels.

[0035] In the embodiments of the present invention, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is connected between the membrane layers and on the surface of the graphene oxide membrane through amide bonds, thereby realizing the in-situ growth of the TP-TTTA material.

[0036] In some embodiments of the present invention, the substrate membrane is selected from one of cellulose acetate membranes, nylon membranes, and polytetrafluoroethylene membranes.

[0037] In some embodiments of the present invention, the pore size of the base membrane is 0.22 μm to 0.40 μm. Exemplarily, the pore size of the base membrane can be one of 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 satisfying the above range.

[0038] The present invention also provides a preparation method of the GO@TP-TTTA composite nanofiltration membrane, which is characterized in that the TP-TTTA material is in-situ grown on the GO membrane.

[0039] 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 a graphene oxide solution and a TTTA solution; phloroglucinol trialdehyde is dissolved in acetic acid solution to prepare a TP-acetic acid solution; the mixed solution of the graphene oxide solution and the TTTA solution is passed through the base 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.

[0040] Figure 1 The flowchart of the preparation method of the GO@TP-TTTA composite nanofiltration membrane is shown, and specifically, it is carried out according to the following steps.

[0041] Prepare the TTTA solution

[0042] 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.

[0043] In some embodiments of the present invention, ultrasonic dispersion treatment is adopted 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.

[0044] As an embodiment of the present invention, 28.36 mg of TTTA is weighed and then dissolved in 28.36 mL of deionized water, and after ultrasonic treatment for 30 min, a uniformly dispersed TTTA solution is obtained.

[0045] Prepare TP - acetic acid solution

[0046] In an embodiment of the present invention, phloroglucinol tri - aldehyde is dissolved in acetic acid solution to prepare a TP - acetic acid solution.

[0047] In an embodiment of the present invention, ultrasonic dispersion treatment is adopted in the preparation of the 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 the 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.

[0048] As an embodiment of the present invention, 33.64 mg of TP is weighed, then it is dissolved in 32 mL of deionized water, and then 1.64 mL of glacial acetic acid (17.5 mol) is added. After ultrasonic treatment for 30 min, a uniformly dispersed TP - acetic acid solution is obtained.

[0049] Prepare graphene oxide solution

[0050] In an embodiment of the present invention, graphene oxide (GO) is dissolved in deionized water to prepare a graphene oxide solution.

[0051] In some embodiments of the present invention, ultrasonic dispersion treatment is adopted in the preparation of the 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 the 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.

[0052] As an embodiment of the present invention, 100 μg of graphene oxide is weighed, then it is dissolved in 30 mL of deionized water. After ultrasonic treatment for 30 min, a uniformly dispersed graphene oxide solution is obtained.

[0053] Prepare graphene oxide / TTTA mixed solution

[0054] In an embodiment of the present invention, TTTA solution is added to the graphene oxide solution to obtain a uniformly mixed graphene oxide / TTTA mixed solution.

[0055] In an embodiment of the present invention, TTTA solution is added to the graphene oxide solution and ultrasonic treatment is carried out to obtain a uniformly dispersed graphene oxide / TTTA mixed solution.

[0056] In some embodiments of the present invention, the time of ultrasonic treatment is 5 min to 10 min. Exemplarily, the time of ultrasonic treatment can be one of 5 min, 6 min, 7 min, 8 min, 9 min, 10 min or any value satisfying the above range.

[0057] 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.

[0058] Vacuum filtration

[0059] In the embodiments of the present invention, the graphene oxide / TTTA mixed solution is filtered onto the surface of the substrate membrane by vacuum filtration to prepare the GO@TTTA seed membrane.

[0060] 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, 2 bar or any value satisfying the above range.

[0061] It is worth mentioning that in order to avoid the fragmentation of the GO@TTTA seed membrane during subsequent soaking, the GO@TTTA seed membrane can be appropriately dried before in-situ growth to improve the stability of the membrane. The drying temperature provided in the embodiments of the present invention can be 50°C to 60°C, and the drying time can be 4 min to 6 min. Exemplarily, the drying temperature can be one of 50°C, 55°C, 60°C or any value satisfying the above range. The drying time can be one of 4 min, 5 min, 6 min or any value satisfying the above range.

[0062] In-situ growth

[0063] In the embodiments of the present invention, the GO@TTTA seed membrane is immersed in the TP-acetic acid solution by in-situ growth method to prepare the GO@TP-TTTA composite nanofiltration membrane.

[0064] In some embodiments of the present invention, in the in-situ growth, the mass ratio of graphene oxide to TP is 1:60 - 80. Exemplarily, 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.

[0065] In some embodiments of the present invention, during in-situ growth, the soaking time or the in-situ growth time of the GO@TTTA seed film can be 2 h to 3 h, not less than 2 h. Exemplarily, the in-situ growth time can be one of 2 h and 3 h or any value satisfying the above range.

[0066] The present invention also provides an application of the above-mentioned GO@TP-TTTA composite nanofiltration membrane or the GO@TP-TTTA composite nanofiltration membrane prepared by the above-mentioned preparation method, for example, it can be applied in water purification.

[0067] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. The experimental reagents used in the following embodiments are all conventional biochemical reagents unless otherwise specified; the raw materials, instruments and equipment used in the following embodiments can all be obtained through market purchase or by existing methods; the dosages of the experimental reagents are all the dosages of the reagents in conventional experimental operations unless otherwise specified; the experimental methods are all conventional methods unless otherwise specified.

[0068] Example 1

[0069] Refer to Figure 1 the preparation process shown to prepare the GO@TP-TTTA composite nanofiltration membrane.

[0070] (1) Weigh 28.36 mg of TTTA and then dissolve it in 28.36 mL of deionized water. After ultrasonic treatment for 30 min, a uniformly dispersed TTTA solution is obtained.

[0071] (2) Weigh 33.64 mg of TP and then dissolve it in 32 mL of deionized water. Then add 1.64 mL of glacial acetic acid (17.5 mol). After ultrasonic treatment for 30 min, a uniformly dispersed TP-acetic acid solution is obtained.

[0072] (3) Weigh 100 μg of graphene oxide (GO) and then dissolve it in 30 mL of deionized water. After ultrasonic treatment for 30 min, a uniformly dispersed graphene oxide solution is obtained.

[0073] (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 perform ultrasonic treatment for 5 min to obtain a uniformly mixed GO@TTTA-500 mixed solution.

[0074] (5) Filter the GO@TTTA-500 mixed solution obtained in step (4) onto the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. After filtration, transfer the formed GO@TTTA-500 seed membrane to an oven for drying at a drying temperature of 60 °C for 5 min.

[0075] (6) Transfer and soak the dried GO@TTTA-500 seed membrane obtained in step (5) into the TP-acetic acid solution obtained in step (2) for in-situ growth for 2 h. After growth, store the formed GO@TP-TTTA-500 composite nanofiltration membrane in deionized water.

[0076] Example 2

[0077] Refer to Figure 1 the preparation process shown to prepare the GO@TP-TTTA composite nanofiltration membrane.

[0078] (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 is obtained.

[0079] (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). After ultrasonic treatment for 30 min, a uniformly dispersed TP / acetic acid solution is obtained.

[0080] (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 is obtained.

[0081] (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 perform ultrasonic treatment for 5 min to obtain a uniformly mixed GO@TTTA-1000 mixed solution.

[0082] (5) Filter the GO@TTTA-1000 mixed solution obtained in step (4) onto the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. After filtration, transfer the formed GO@TTTA-1000 seed membrane to an oven for drying at a drying temperature of 60 °C for 5 min.

[0083] (6) Transfer and soak the dried GO@TTTA-1000 seed membrane obtained in step (5) into the TP-acetic acid solution obtained in step (2) for in-situ growth for 2 h. After growth, store the formed GO@TP-TTTA-1000 composite nanofiltration membrane in deionized water.

[0084] Comparative Example 1

[0085] Prepare a GO nanofiltration membrane.

[0086] (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 ultrasonically treat for 30 min to obtain a uniformly dispersed TP - acetic acid solution.

[0087] (2) Take 100 μg of graphene oxide (GO) and add it to 30 mL of water, ultrasonically treat for 5 min to make it uniformly mixed, and obtain a uniform GO solution.

[0088] (3) Filter the GO solution obtained in step (2) onto the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. After filtration is completed, transfer the formed GO membrane to an oven for drying at a drying temperature of 60 °C and a drying time of 5 min.

[0089] (4) Transfer and soak the dried GO membrane obtained in step (3) into the TP - acetic acid solution obtained in step (1) for in - situ growth for 2 h. After the growth is completed, store the formed GO composite nanofiltration membrane in deionized water.

[0090] Comparative Example 2

[0091] Refer to Figure 1 the preparation process shown to prepare a GO@TP - TTTA composite nanofiltration membrane.

[0092] (1) Weigh 28.36 mg of TTTA and dissolve it in 28.36 mL of deionized water, ultrasonically treat for 30 min to obtain a uniformly dispersed TTTA solution.

[0093] (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 ultrasonically treat for 30 min to obtain a uniformly dispersed TP - acetic acid solution.

[0094] (3) Weigh 100 μg of graphene oxide (GO) and dissolve it in 30 mL of deionized water, ultrasonically treat for 30 min to obtain a uniformly dispersed graphene oxide solution.

[0095] (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 and ultrasonically treat for 5 min to obtain a uniformly mixed GO@TTTA - 2000 mixed solution.

[0096] (5) Filter the GO@TTTA-2000 mixed solution obtained in step (4) onto the surface of an organic nylon membrane with a diameter of 47 mm and a pore size of 0.22 μm. After filtration, transfer the formed GO@TTTA-2000 seed membrane to an oven for drying at a temperature of 60 °C for 5 min.

[0097] (6) Transfer and soak the dried GO@TTTA-2000 seed membrane obtained in step (5) into the TP-acetic acid solution obtained in step (2) for in-situ growth for 2 h. After growth, store the formed GO@TP-TTTA-2000 composite nanofiltration membrane in deionized water.

[0098] Performance detection

[0099] Characterize the surface and cross-sectional morphology, wetting properties, etc. 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 to 2. At the same time, detect and analyze the pure water flux and the rejection of dye molecules. The results are as Figures 2 to 4 shown.

[0100] Use a standard terminal filtration device, including a nitrogen cylinder, a digital balance, an ultrafiltration cup (MSC-50, MOSU China Co., Ltd.) and a computer, to evaluate the water permeability of the prepared membrane. Under a pressure of 1.0 bar, use a digital balance to monitor the mass of the filtrate. The water flux is calculated using Equation (1).

[0101] (1)

[0102] In Equation (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).

[0103] In the present invention, the rejection ability of each membrane is detected by filtering a 20 ppm dye solution. All samples were measured at least three times. The dye concentrations in the feed and filtrate were analyzed using a UV-visible spectrophotometer. The rejection rate is calculated according to Equation (2).

[0104] (2)

[0105] In Equation (2), R is the rejection rate, and C0 and C1 are the dye concentrations before and after filtration, respectively.

[0106] CombinationFigure 2 A in Figure 2 As shown by B in

[0107] Combined with Figure 2 C in Figure 2 and D in

[0108] As shown, 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. Figure 3 Combined with Figure 3 (a) in -2 ·h -1 ·bar -1 and the pure water flux of the GO@TP-TTTA-1000 composite nanofiltration membrane increases to 276.3 L·m -2 ·h -1 ·bar -1 .

[0109] 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 were subjected to separation performance tests and applied to the filtration separation of Coomassie Brilliant Blue (BBG).

[0110] As Figure 4 shown, the rejection rate of the GO composite nanofiltration membrane in Comparative Example 1 for BBG was 99%, the rejection rate of the GO@TP-TTTA-500 composite nanofiltration membrane in Example 1 for BBG was 99.0%, the rejection rate of the GO@TP-TTTA-1000 composite nanofiltration membrane in Example 2 for BBG was 98.3%, and the rejection rate of the GO@TP-TTTA-2000 composite nanofiltration membrane in Comparative Example 2 for BBG was 79.1%.

[0111] In addition, the anti-fouling performance tests of the GO@TP-TTTA-1000 composite nanofiltration membrane prepared in Example 2 and the GO composite nanofiltration membrane prepared in the comparative example for BBG were carried out.

[0112] As Figure 5 shown, the flux recovery rate of the GO composite nanofiltration membrane in Comparative Example 1 was 78%, and the flux recovery rate of the GO@TP-TTTA-1000 composite nanofiltration membrane in Example 2 was 93%.

[0113] 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 performance.

[0114] 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 foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention. In particular, as long as there is no structural conflict, the 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 falling within the scope of the claims.

Claims

1. A method for preparing a GO@TP-TTTA composite nanofiltration membrane, characterized in that: The GO@TP-TTTA composite nanofiltration membrane includes a base membrane and a graphene oxide membrane formed on the surface of one side of the base membrane, 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, 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 a carbon-carbon double bond; 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; Passing a mixed solution of graphene oxide solution and TTTA solution through a substrate membrane by vacuum filtration to obtain a GO@TTTA seed membrane; in the mixed solution, the mass ratio of the graphene oxide to the TTTA is 1:5-10; The GO@TTTA seed membrane is immersed in the TP-acetic acid solution, and in-situ growth is performed at room temperature to obtain the GO@TP-TTTA composite nanofiltration membrane; in the in-situ growth, the mass ratio of the graphene oxide to the TP is 1:60-80.

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

3. The method for preparing 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 method for preparing 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. The method for preparing the GO@TP-TTTA composite nanofiltration membrane according to claim 1, 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.

6. The method for preparing the GO@TP-TTTA composite nanofiltration membrane according to claim 1, 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.

7. Use of a 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 1 to 6 in water purification.

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