A Ti3C2T x Preparation method of MXene quantum dot composite polyamide reverse osmosis membrane

Abstract

The application belongs to the technical field of membrane separation, and discloses a Ti3C2T x MXene quantum dot composite polyamide reverse osmosis membrane preparation method, first, Ti3C2T x MXene material is subjected to liquid nitrogen intercalation treatment and interlayer expansion, and Ti3C2T x MXene quantum dot nanomaterial; then, Ti3C2T x MXene quantum dot nanomaterial is prepared; the polyamine aqueous solution and the polyacyl chloride solution; the ultrafiltration base film is soaked in the water-phase monomer solution, the water-phase monomer solution on the film surface is blown dry; then, the base film is immersed into the organic-phase solution, interface polymerization reaction occurs, and an active layer is formed; the composite film after interface polymerization is placed and subjected to heating treatment, and interface polymerization reaction is further promoted to occur. The preparation process is simple, the prepared reverse osmosis membrane has good membrane performance, that is, has higher water flux and better anti-pollution performance.

Description

Technical Field

[0001] This invention belongs to the field of membrane separation technology and relates to a Ti3C2T x The preparation method of MXene quantum dot composite polyamide reverse osmosis membrane can be used in the fields of seawater desalination, sewage treatment or radioactive wastewater treatment. Background Technology

[0002] Currently, reverse osmosis membrane technology has achieved rapid development, demonstrating significant advantages in seawater desalination, brackish water desalination, and pure / ultrapure water production. In recent years, with the advancement of reverse osmosis technology, the cost of reverse osmosis membranes has continuously decreased, making it the most widely used seawater desalination technology globally. Currently, polyamide reverse osmosis membranes, which dominate the reverse osmosis membrane market, are mostly produced by the interfacial polymerization of m-phenylenediamine (dissolved in the aqueous phase) and trimesoyl chloride (dissolved in the organic phase) on the ultrafiltration membrane surface. Due to the insufficient hydrophilicity of polyamide materials, their water flux is limited to some extent, restricting the efficiency of the reverse osmosis membrane. Furthermore, the insufficient hydrophilicity of polyamide reverse osmosis membranes makes the membrane material susceptible to fouling, increasing the operating costs of the reverse osmosis process. Therefore, developing a method that can simultaneously improve the water flux performance and antifouling performance of polyamide membrane materials is essential.

[0003] In 2011, Gogotsi and Barsoum discovered a new two-dimensional material—the transition metal carbide / nitride MXene—whose precursor is the layered metal ceramic M. n+1 AX n The MXene phase (MAX phase) typically consists of n (1-3), M (usually a transition metal), A (a Group III or IV element), and X (carbon or nitrogen atom). The currently reported MXene family is large, with approximately 70 members, among which Ti3C2T is a prominent example. x Novel materials, represented by MXene, have attracted great attention from researchers due to their advantages of hydrophilicity and radiation resistance, and are widely used in the preparation and research of membrane material modification.

[0004] Xiaoying Wang et al. used Ti3C2T x The introduction of MXene into polyamide reverse osmosis membranes increases the water flux of the reverse osmosis membrane from approximately 27.2 Lm. -2 ·h -1 Increased to 40.5Lm -2 ·h -1Under conditions of 60 ppm bovine serum albumin contamination, the membrane water flux decrease rate was only 11.1% within 6 hours [Xiaoying Wang, Qingqing Li, Jianfeng Zhang, Haimeng Huang, Shaoyu Wu, Yan Yang. Journal of Membrane Science, 2020, 603:118036]. Chinese Patent CN 113600013 A discloses a high-flux Ti3C2T... x MXene / cellulose nanofiber-polyamide reverse osmosis composite membrane and its preparation method, by using Ti3C2T x MXene / cellulose nanomaterials were used to modify polyamide reverse osmosis membranes, resulting in a water flux increase of 70 Lm at a pressure of 1.6 MPa. -2 ·h -1 .

[0005] The above research can illustrate that Ti3C2T x The introduction of MXene nanomaterials has a considerable effect on improving the separation performance of reverse osmosis membranes. However, Ti3C2T x The aggregation problem of MXene nanomaterials limits the effective improvement of reverse osmosis membrane water flux. Therefore, how to improve Ti3C2T x Dispersing MXene nanomaterials solves the problem of self-agglomeration, further achieving higher water flux and antifouling performance, and has become an important research direction for reverse osmosis membranes. Summary of the Invention

[0006] (a) Purpose of the invention

[0007] The purpose of this invention is to address the problems of insufficient water flux and poor antifouling performance of existing reverse osmosis membranes by proposing a Ti3C2T membrane with high water flux and strong antifouling performance. x Preparation method of MXene quantum dot composite polyamide reverse osmosis membrane.

[0008] (II) Technical Solution

[0009] To solve the above-mentioned technical problems, the present invention provides a Ti3C2T x The preparation method of MXene quantum dot composite polyamide reverse osmosis membrane includes the following steps:

[0010] Step 1: Ti3C2T x Preparation of MXene materials

[0011] A certain amount of Ti3AlC2 powder was immersed in an HF solution of a certain concentration for etching, and stirred at 30-50℃ for 48-72 h. After etching, the solution was repeatedly washed with deionized water and anhydrous ethanol until the pH of the solution was greater than 6.5. The washed solution was then freeze-dried under vacuum at 70-90℃ for 12-36 h to obtain Ti3C2T. x MXene material powder;

[0012] Step 2: Ti3C2T x Preparation of MXene quantum dots

[0013] Take 1~10g of Ti3C2T obtained in step one x MXene powder was placed in a polytetrafluoroethylene beaker, and 10-50 mL of liquid nitrogen was poured into the beaker. The mixture was allowed to stand at room temperature for 3-10 minutes. Then, 30-50 mL of deionized water at 80-100°C was added, and the mixture was reacted for 3-5 minutes. The mixture was stirred at room temperature for 24-36 hours. After filtration through a 220 nm pore size filter membrane and centrifugation at 10000 r / min for 10-30 minutes, Ti3C2T was obtained. x MXene quantum dot solution was freeze-dried for 24–48 h to obtain Ti3C2T. x MXene quantum dot nanomaterials.

[0014] Step 3: Preparation of aqueous monomer solution

[0015] A certain amount of polyamine was dissolved in deionized water, and a certain amount of Ti3C2T was added. x MXene quantum dot nanomaterials were stirred evenly to prepare an aqueous monomer solution.

[0016] Step 4: Preparation of Organic Phase Solution

[0017] A certain amount of polyacryl chloride is dissolved in an organic solvent and stirred evenly to prepare an organic phase solution;

[0018] Step 5: Interfacial Polymerization Reaction

[0019] Immerse the ultrafiltration membrane in an aqueous monomer solution for 2-20 minutes, and then dry the aqueous monomer solution on the membrane surface with an air knife. Next, immerse the membrane in an organic phase solution for 2-200 seconds to allow interfacial polymerization to occur and form an active layer. Place the composite membrane after interfacial polymerization vertically for 50-100 seconds, and then place it in an oven at 40-90°C for 8-20 minutes to further promote the interfacial polymerization reaction.

[0020] In step one, the mass percentage concentration of the HF acid described in this invention is 30-50%.

[0021] In step three, the polyamines are m-phenylenediamine (MPD), o-phenylenediamine (OPD), p-phenylenediamine (PPD), and m-phenylenediamine (MXDA). N , N One or a mixture of more than one of dimethylphenyl diammonium (DMMPD) and 4-methylm-phenylenediamine (MMPD).

[0022] In step three, Ti3C2T x MXene quantum dot nanoparticles have a diameter of 2-50 nm and a thickness of 1-20 nm.

[0023] In step three, the mass percentage concentration of the polyamine is 0.1-5%, and Ti3C2T x The mass percentage concentration of MXene quantum dot nanoparticles is 0.001~0.1%.

[0024] In step four, the acyl chloride is one or a mixture of more than one of the following: trimesoyl chloride (TMC), phthaloyl chloride (OPC), isophthaloyl chloride (IPC), 1,3,5-cyclohexanetrioyl chloride (HT), and methyl isophthalonitrile ester (TDI).

[0025] In step four, the mass percentage concentration of polyacrylamide chloride is 0.01~2.5%.

[0026] (III) Beneficial Effects

[0027] The Ti3C2T provided by the above technical solution x Preparation method of MXene quantum dot composite polyamide reverse osmosis membrane, using Ti3C2T obtained through "micro-explosion". x MXene quantum dot polyamide composites improve Ti3C2T x The dispersibility, hydrophilicity, and negative charge of MXene material effectively increase the water flux and antifouling performance of polyamide reverse osmosis membranes while ensuring the salt rejection rate of the composite membrane. This allows for controllable structure of the reverse osmosis composite membrane, resulting in the fabrication of Ti3C2T. x MXene quantum dot composite polyamide reverse osmosis membrane material has advantages such as high salt rejection rate, high water flux and high antifouling ability, which is of great practical significance for the application of high-performance reverse osmosis membranes in the fields of seawater desalination, sewage treatment or radioactive wastewater treatment. Attached Figure Description

[0028] Figure 1 These are scanning electron microscope images of the reverse osmosis composite membranes prepared in Example 3 and Comparative Examples 1 and 2 of this invention.

[0029] Figure 2 These are scanning electron microscope images of the cross-sections of the reverse osmosis composite membranes prepared in Example 3 and Comparative Examples 1 and 2 of this invention;

[0030] Figure 3 The Ti3C2T obtained in step 1 of Embodiment 1 of this invention x Photoluminescence spectra of MXene quantum dots under excitation at 340-500 nm. Detailed Implementation

[0031] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0032] Example 1

[0033] A Ti3C2T x The specific steps for using MXene quantum dot composite polyamide reverse osmosis membrane are as follows:

[0034] (1) 10.0 g of Ti3AlC2 powder was immersed in a 40% HF solution for etching and stirred at 35 °C for 72 h. After etching, the solution was washed four times with deionized water and anhydrous ethanol. The pH of the solution after washing was 6.8. The washed solution was freeze-dried and vacuum-dried at 90 °C for 24 h to obtain Ti3C2T x MXene material powder.

[0035] (2) Take 5.0g of Ti3C2T obtained in step (1) x MXene powder was placed in a polytetrafluoroethylene beaker, and 20 mL of liquid nitrogen was poured into the beaker. The mixture was allowed to stand at room temperature for 5 minutes. Then, 30 mL of deionized water at 95°C was added, and the mixture was reacted for 4 minutes. The mixture was stirred at room temperature for 24 hours, filtered through a 220 nm pore size membrane, and centrifuged at 10000 r / min for 20 minutes to obtain Ti3C2T. x MXene quantum dot solution was freeze-dried for 48 h to obtain Ti3C2T x MXene quantum dot nanomaterial powder.

[0036] (3) Dissolve the powder obtained in step (2) in an aqueous solution of m-phenylenediamine (MPD) with a mass concentration of 3.0% at a mass concentration of 0.001%. Then pour 100 mL of the mixture onto the surface of the ultrafiltration membrane and soak for 5 min. Use an air knife to dry the aqueous monomer solution on the surface of the membrane.

[0037] (4) The base film was immersed in a 0.15% (w / w) solution of trimesoyl chloride organic phase for 60 s to undergo interfacial polymerization and form an active layer. The composite film after interfacial polymerization was placed vertically for 60 s and then placed in an oven at 90 ℃ for 8 min to further promote the interfacial polymerization reaction, thus obtaining Ti3C2T xMXene quantum dot composite reverse osmosis membrane.

[0038] The prepared samples were observed and analyzed using scanning electron microscopy and other methods. The samples were then used to test water flux performance, salt rejection performance, and antifouling performance. Specific test conditions were as follows: at 25±0.1℃, a flow rate of 0.19 m / s, and a test pressure of 225 psi (1.55 MPa), the composite membrane was used to treat 2000 ppm NaCl solution, determining the water flux and salt rejection rate. The water flux Q = J / (A·t), where J is the water permeate (L) and Q is the water flux (L / m³). 2 ·h), where A is the effective membrane area of ​​the reverse osmosis membrane (m²). 2 ), where t is time (h). Salt rejection rate R = (C p -C f ) / C p ×100%, where C p C represents the concentration of NaCl in the original solution. f The concentration of NaCl in the permeate is given. The biofouling resistance of the reverse osmosis composite membrane was tested using a diluted solution of *E. coli* cells as a contaminant. The composite polyamide reverse osmosis membrane was used at a concentration of 1.7 × 10⁻⁶. 7 The cells were immersed in a 1 / ml E. coli cell solution and incubated at 30°C. They were then immersed under UV light for 4 hours daily for 1, 2, and 3 days. After each day's incubation, the water flux Q of the contaminated composite polyamide reverse osmosis membrane was measured when treating a 2000 ppm NaCl solution. d1 Q d2 and Q d3 The biofouling resistance of the reverse osmosis composite membrane was assessed by observing the decrease in membrane water flux. The feed solution was replaced with a mixed aqueous solution of NaCl and bovine serum albumin (BSA) (NaCl concentration 2000 ppm, BSA concentration 1000 ppm), and the relative water flux recovery rate was calculated to test the organic fouling resistance of the membrane. Initially, using only 2000 ppm NaCl as the feed solution, the composite polyamide reverse osmosis membrane was tested for separation performance for 6 hours at a pressure of 1.5 MPa, and its water flux Q0 was recorded. Then, using a prepared mixed feed solution containing BSA under the same conditions, the composite polyamide reverse osmosis membrane was tested for separation performance for 6 hours, and the membrane water flux was recorded as Q0. t Then, the membrane was thoroughly cleaned with deionized water for 0.5 hours. Each test lasted 12 hours and constituted one cycle. After three cycles, the recovery rate Q of the relative water flux was calculated. r =Q t / Q0×100%.

[0039] Example 2

[0040] A Ti3C2T x The specific steps for using MXene quantum dot composite polyamide reverse osmosis membrane are as follows:

[0041] (1) 10.0 g of Ti3AlC2 powder was immersed in a 40% HF solution for etching and stirred at 35 °C for 72 h. After etching, the solution was washed four times with deionized water and anhydrous ethanol. The pH of the solution after washing was 6.8. The washed solution was freeze-dried and vacuum-dried at 90 °C for 24 h to obtain Ti3C2T x MXene material powder.

[0042] (2) Take 5.0g of Ti3C2T obtained in step (1) x MXene powder was placed in a polytetrafluoroethylene beaker, and 20 mL of liquid nitrogen was poured into the beaker. The mixture was allowed to stand at room temperature for 5 minutes. Then, 30 mL of deionized water at 95°C was added, and the mixture was reacted for 4 minutes. The mixture was stirred at room temperature for 24 hours, filtered through a 220 nm pore size membrane, and centrifuged at 10000 r / min for 20 minutes to obtain Ti3C2T. x MXene quantum dot solution was freeze-dried for 48 h to obtain Ti3C2T x MXene quantum dot nanomaterial powder.

[0043] (3) Dissolve the powder obtained in step (2) in an MPD aqueous solution with a mass concentration of 3.0% at a mass concentration of 0.005%. Then pour 100 mL of the mixture onto the surface of the ultrafiltration membrane and soak for 5 min. Use an air knife to dry the aqueous monomer solution on the surface of the membrane.

[0044] (4) The base film was immersed in a 0.15% (w / w) solution of trimesoyl chloride organic phase for 60 s to undergo interfacial polymerization and form an active layer. The composite film after interfacial polymerization was placed vertically for 60 s and then placed in an oven at 90 ℃ for 8 min to further promote the interfacial polymerization reaction, thus obtaining Ti3C2T x The MXene quantum dot composite reverse osmosis membrane was prepared, and the resulting sample was observed and analyzed using scanning electron microscopy and other methods. The sample was then used to study water flux performance, salt rejection performance, and antifouling performance. The specific testing process was consistent with that in Example 1.

[0045] Example 3

[0046] A Ti3C2T x The specific steps for using MXene quantum dot composite polyamide reverse osmosis membrane are as follows:

[0047] (1) 10.0 g of Ti3AlC2 powder was immersed in a 40% HF solution for etching and stirred at 35 °C for 72 h. After etching, the solution was washed four times with deionized water and anhydrous ethanol. The pH of the solution after washing was 6.8. The washed solution was freeze-dried and vacuum-dried at 90 °C for 24 h to obtain Ti3C2T x MXene material powder.

[0048] (2) Take 5.0g of Ti3C2T obtained in step (1) x MXene powder was placed in a polytetrafluoroethylene beaker, and 20 mL of liquid nitrogen was poured into the beaker. The mixture was allowed to stand at room temperature for 5 minutes. Then, 30 mL of deionized water at 95°C was added, and the mixture was reacted for 4 minutes. The mixture was stirred at room temperature for 24 hours, filtered through a 220 nm pore size membrane, and centrifuged at 10000 r / min for 20 minutes to obtain Ti3C2T. x MXene quantum dot solution was freeze-dried for 48 h to obtain Ti3C2T x MXene quantum dot nanomaterial powder.

[0049] (3) Dissolve the powder obtained in step (2) in an MPD aqueous solution with a mass concentration of 3.0% at a mass concentration of 0.010%. Then pour 100 mL of the mixture onto the surface of the ultrafiltration membrane and soak for 5 min. Use an air knife to dry the aqueous monomer solution on the surface of the membrane.

[0050] (4) The base film was immersed in a 0.15% (w / w) solution of trimesoyl chloride organic phase for 60 s to undergo interfacial polymerization and form an active layer. The composite film after interfacial polymerization was placed vertically for 60 s and then placed in an oven at 90 ℃ for 8 min to further promote the interfacial polymerization reaction, thus obtaining Ti3C2T x The MXene quantum dot composite reverse osmosis membrane was prepared, and the resulting sample was observed and analyzed using scanning electron microscopy and other methods. The sample was then used to study water flux performance, salt rejection performance, and antifouling performance. The specific testing process was consistent with that in Example 1.

[0051] Example 4

[0052] A Ti3C2T x The specific steps for using MXene quantum dot composite polyamide reverse osmosis membrane are as follows:

[0053] (1) 10.0 g of Ti3AlC2 powder was immersed in a 40% HF solution for etching and stirred at 35 °C for 72 h. After etching, the solution was washed four times with deionized water and anhydrous ethanol. The pH of the solution after washing was 6.8. The washed solution was freeze-dried and vacuum-dried at 90 °C for 24 h to obtain Ti3C2Tx MXene material powder.

[0054] (2) Take 5.0g of Ti3C2T obtained in step (1) x MXene powder was placed in a polytetrafluoroethylene beaker, and 20 mL of liquid nitrogen was poured into the beaker. The mixture was allowed to stand at room temperature for 5 minutes. Then, 30 mL of deionized water at 95°C was added, and the mixture was reacted for 4 minutes. The mixture was stirred at room temperature for 24 hours, filtered through a 220 nm pore size membrane, and centrifuged at 10000 r / min for 20 minutes to obtain Ti3C2T. x MXene quantum dot solution was freeze-dried for 48 h to obtain Ti3C2T x MXene quantum dot nanomaterial powder.

[0055] (3) Dissolve the powder obtained in step (2) in MPD solution with a mass concentration of 3.0% at a mass concentration of 0.050%. Then pour 100 mL of the mixture onto the surface of the ultrafiltration membrane and soak for 5 min. Use an air knife to dry the aqueous monomer solution on the surface of the membrane.

[0056] (4) The base film was immersed in a 0.15% (w / w) solution of trimesoyl chloride organic phase for 60 s to undergo interfacial polymerization and form an active layer. The composite film after interfacial polymerization was placed vertically for 60 s and then placed in an oven at 90 ℃ for 8 min to further promote the interfacial polymerization reaction, thus obtaining Ti3C2T x The MXene quantum dot composite reverse osmosis membrane was prepared, and the resulting sample was observed and analyzed using scanning electron microscopy and other methods. The sample was then used to study water flux performance, salt rejection performance, and antifouling performance. The specific testing process was consistent with that in Example 1.

[0057] Example 5

[0058] A Ti3C2T x The specific steps for using MXene quantum dot composite polyamide reverse osmosis membrane are as follows:

[0059] (1) 10.0 g of Ti3AlC2 powder was immersed in a 40% HF solution for etching and stirred at 35 °C for 72 h. After etching, the solution was washed four times with deionized water and anhydrous ethanol. The pH of the solution after washing was 6.8. The washed solution was freeze-dried and vacuum-dried at 90 °C for 24 h to obtain Ti3C2T x MXene material powder.

[0060] (2) Take 5.0g of Ti3C2T obtained in step (1) xMXene powder was placed in a polytetrafluoroethylene beaker, and 20 mL of liquid nitrogen was poured into the beaker. The mixture was allowed to stand at room temperature for 5 minutes. Then, 30 mL of deionized water at 95°C was added, and the mixture was reacted for 4 minutes. The mixture was stirred at room temperature for 24 hours, filtered through a 220 nm pore size membrane, and centrifuged at 10000 r / min for 20 minutes to obtain Ti3C2T. x MXene quantum dot solution was freeze-dried for 48 h to obtain Ti3C2T x MXene quantum dot nanomaterial powder.

[0061] (3) Dissolve the powder obtained in step (2) in an MPD aqueous solution with a mass concentration of 3.0% at a mass concentration of 0.10%. Then pour 100 mL of the mixture onto the surface of the ultrafiltration membrane and soak for 5 min. Use an air knife to dry the aqueous monomer solution on the surface of the membrane.

[0062] (4) The base film was immersed in a 0.15% (w / w) solution of trimesoyl chloride organic phase for 60 s to undergo interfacial polymerization and form an active layer. The composite film after interfacial polymerization was placed vertically for 60 s and then placed in an oven at 90 ℃ for 8 min to further promote the interfacial polymerization reaction, thus obtaining Ti3C2T x The MXene quantum dot composite reverse osmosis membrane was prepared, and the resulting sample was observed and analyzed using scanning electron microscopy and other methods. The sample was then used to study water flux performance, salt rejection performance, and antifouling performance. The specific testing process was consistent with that in Example 1.

[0063] Example 6

[0064] A Ti3C2T x The specific steps for using MXene quantum dot composite polyamide reverse osmosis membrane are as follows:

[0065] (1) 10.0 g of Ti3AlC2 powder was immersed in a 40% HF solution for etching and stirred at 35 °C for 72 h. After etching, the solution was washed four times with deionized water and anhydrous ethanol. The pH of the solution after washing was 6.8. The washed solution was freeze-dried and vacuum-dried at 90 °C for 24 h to obtain Ti3C2T x MXene material powder.

[0066] (2) Take 5.0g of Ti3C2T obtained in step (1) x MXene powder was placed in a polytetrafluoroethylene beaker, and 20 mL of liquid nitrogen was poured into the beaker. The mixture was allowed to stand at room temperature for 5 minutes. Then, 30 mL of deionized water at 95°C was added, and the mixture was reacted for 4 minutes. The mixture was stirred at room temperature for 24 hours, filtered through a 220 nm pore size membrane, and centrifuged at 10000 r / min for 20 minutes to obtain Ti3C2T.x MXene quantum dot solution was freeze-dried for 48 h to obtain Ti3C2T x MXene quantum dot nanomaterial powder.

[0067] (3) Dissolve the powder obtained in step (2) in an aqueous solution of o-phenylenediamine with a mass concentration of 3.0% at a mass concentration of 0.010%. Then pour 100 mL of the mixture onto the surface of the ultrafiltration membrane and soak for 5 min. Use an air knife to dry the aqueous monomer solution on the surface of the membrane.

[0068] (4) The base film was immersed in a 0.15% (w / w) solution of isotrimethylammonium chloride organic phase for 60 s to undergo interfacial polymerization and form an active layer. The composite film after interfacial polymerization was placed vertically for 60 s and then placed in an oven at 90 ℃ for 8 min to further promote the interfacial polymerization reaction, thus obtaining Ti3C2T x The MXene quantum dot composite reverse osmosis membrane was prepared, and the resulting sample was observed and analyzed using scanning electron microscopy and other methods. The sample was then used to study water flux performance, salt rejection performance, and antifouling performance. The specific testing process was consistent with that in Example 1.

[0069] Comparative Example 1

[0070] (1) Prepare an aqueous solution of MPD with a mass concentration of 3.0%, then pour 100 mL of the solution onto the surface of the ultrafiltration membrane and soak for 5 min. Use an air knife to dry the aqueous monomer solution on the surface of the membrane.

[0071] (2) The base membrane was immersed in a 0.15% (w / w) trimethylbenzene chloride organic phase solution for 60s to undergo interfacial polymerization and form an active layer. The composite membrane after interfacial polymerization was placed vertically for 60s and then placed in an oven at 90°C for 8min to further promote the interfacial polymerization reaction and obtain a polyamide reverse osmosis membrane. The obtained sample was observed and analyzed by scanning electron microscopy and other methods. The sample was used for the study of water flux performance, salt rejection performance and antifouling performance. The specific testing process was consistent with that in Example 1.

[0072] Comparative Example 2

[0073] (1) 10.0 g of Ti3AlC2 powder was immersed in a 40% HF solution for etching and stirred at 35 °C for 72 h. After etching, the solution was washed four times with deionized water and anhydrous ethanol. The pH of the solution after washing was 6.8. The washed solution was freeze-dried and vacuum-dried at 90 °C for 24 h to obtain Ti3C2T x MXene material powder.

[0074] (2) Dissolve the powder obtained in step (1) in an MPD aqueous solution with a mass concentration of 3.0% at a mass concentration of 0.010%. Then pour 100 mL of the mixture onto the surface of the ultrafiltration membrane and soak for 5 min. Use an air knife to dry the aqueous monomer solution on the surface of the membrane.

[0075] (3) The base film was immersed in a 0.15% (w / w) trimethylbenzene chloride organic phase solution for 60s to undergo interfacial polymerization and form an active layer. The composite film after interfacial polymerization was placed vertically for 60s, and then placed in an oven at 90℃ for 8min to further promote the interfacial polymerization reaction, thus obtaining Ti3C2T x The MXene polyamide reverse osmosis membrane was used to observe and analyze the prepared samples using scanning electron microscopy and other methods. The samples were then used to study water flux performance, salt rejection performance, and antifouling performance. The specific testing process was consistent with that in Example 1.

[0076] Experimental results:

[0077] I. The polyamide composite reverse osmosis membranes in Examples 1-6 and Comparative Examples 1-2 were tested for water flux, rejection rate, and antifouling performance using the methods described above. The test results are as follows:

[0078]

[0079] As can be seen from the data in the table, the water flux of Examples 1-6 is significantly higher than that of the ordinary reverse osmosis membranes (32.5 LMH) in Comparative Examples 1 and 2, without excessive loss of salt rejection rate. With the gradual increase of quantum dot concentration, the water flux of the composite membrane also gradually increases, but after reaching a certain concentration (Example 5), its salt rejection rate begins to decrease. The antifouling performance shows that both resistance to biological and organic fouling have been improved to a certain extent. Therefore, the composite reverse osmosis membrane prepared by the method provided in this invention has high water flux and antifouling performance, and the preparation method is simple, making it highly promising for industrial applications.

[0080] As can be seen from the above technical solution, the present invention has the following significant features:

[0081] (1) This invention prepares Ti3C2T by a simple low-temperature “micro-explosion” method. x MXene quantum dots. The principle behind this is the use of Ti3C2T... x The accordion-like microstructure of MXene material was utilized through intercalation with liquid nitrogen, followed by the addition of high-temperature deionized water to create a temperature difference. This caused the liquid nitrogen to rapidly expand between the layers, resulting in a "micro-explosion" reaction. Ti3C2T was successfully prepared using this method. xMXene quantum dots have surface groups that can easily form hydrogen bonds with water, resulting in better hydrophilicity and good dispersion in water, eliminating the need for stirring and ultrasonic treatment.

[0082] (2) The present invention uses Ti3C2T x MXene quantum dots are introduced into the aqueous solution of the interface polymerization process to generate the polyamide layer of the reverse osmosis membrane, which further improves the performance of Ti3C2T. x The dispersibility of MXene nanomaterials offers a new solution, thereby improving the water flux and antifouling performance of reverse osmosis membranes, and further expanding the application of Ti3C2T. x The application of MXene nanomaterials as a novel additive in improving the performance of polyamide reverse osmosis membranes.

[0083] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A Ti3C2T x A method for preparing an MXene quantum dot composite polyamide reverse osmosis membrane, characterized in that, Includes the following steps: S1: Ti3C2T x Preparation of MXene quantum dot nanomaterials For Ti3C2T x Ti3C2T was prepared by liquid nitrogen intercalation and interlayer expansion of MXene material. x MXene quantum dot nanomaterials; S2: Preparation of aqueous monomer solution The aqueous monomer solution is prepared by adding Ti3C2T x MXene quantum dot nanomaterials in a polyamine aqueous solution; S3: Preparation of organic phase solution The organic phase solution is a polyacrylamide chloride solution; S4: Interfacial polymerization reaction The ultrafiltration membrane was immersed in an aqueous monomer solution, and the aqueous monomer solution on the membrane surface was dried. The base membrane is then immersed in an organic phase solution to undergo interfacial polymerization and form an active layer. The composite membrane after interfacial polymerization is left to stand and then subjected to heat treatment to further promote the interfacial polymerization reaction. In step S1, Ti3C2T x The preparation process of MXene quantum dot nanomaterials is as follows: S11: Ti3C2T x Preparation of MXene materials Ti3AlC2 powder was immersed in HF solution for etching, and stirred at 30-50℃ for 48-72 h. After etching, the solution was repeatedly washed with deionized water and anhydrous ethanol until the pH of the washing solution was greater than 6.

5. The washed solution was then freeze-dried under vacuum at 70-90℃ for 12-36 h to obtain Ti3C2T. x MXene material powder; S12: Ti3C2T x Preparation of MXene quantum dots The 1~10g Ti3C2T obtained in step S11 x MXene powder was placed in a polytetrafluoroethylene beaker, and 10-50 mL of liquid nitrogen was poured into the beaker. The mixture was allowed to stand at room temperature for 3-10 minutes. Then, 30-50 mL of deionized water at 80-100°C was added, and the mixture was reacted for 3-5 minutes. The mixture was stirred at room temperature for 24-36 hours. After filtration through a 220 nm pore size filter membrane and centrifugation at 10000 r / min for 10-30 minutes, Ti3C2T was obtained. x MXene quantum dot solution was freeze-dried for 24–48 h to obtain Ti3C2T. x MXene quantum dot nanomaterials.

2. The Ti3C2T as described in claim 1 x A method for preparing an MXene quantum dot composite polyamide reverse osmosis membrane, characterized in that, In step S2, the preparation process of the aqueous monomer solution is as follows: dissolve the polyamine in deionized water, and add Ti3C2T x MXene quantum dot nanomaterials were stirred evenly to form an aqueous monomer solution.

3. The Ti3C2T as described in claim 2 x A method for preparing an MXene quantum dot composite polyamide reverse osmosis membrane, characterized in that, In step S3, the organic phase solution is prepared by dissolving polyacrylamide chloride in an organic solvent and stirring until homogeneous to form an organic phase solution.

4. The Ti3C2T as described in claim 3 x A method for preparing an MXene quantum dot composite polyamide reverse osmosis membrane, characterized in that, In step S4, the ultrafiltration membrane is immersed in an aqueous monomer solution for 2-20 minutes, and the aqueous monomer solution on the membrane surface is dried with an air knife. The base film is then immersed in the organic phase solution for 2-200 seconds to undergo interfacial polymerization and form an active layer. The composite film after interfacial polymerization is placed vertically for 50-100 seconds and then placed in an oven at 40-90°C for 8-20 minutes to further promote the interfacial polymerization reaction.

5. The Ti3C2T as described in claim 1 x A method for preparing an MXene quantum dot composite polyamide reverse osmosis membrane, characterized in that, In step S11, the mass percentage concentration of the HF solution is 30-50%.

6. The Ti3C2T as described in claim 5 x A method for preparing an MXene quantum dot composite polyamide reverse osmosis membrane, characterized in that, In step S1, Ti3C2T x MXene quantum dot nanoparticles have a diameter of 2-50 nm and a thickness of 1-20 nm.

7. The Ti3C2T as described in claim 6 x A method for preparing an MXene quantum dot composite polyamide reverse osmosis membrane, characterized in that, In step S2, the polyamine is m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-phenylenediamine, N , N -Dimethylphenylenediamine, 4-methyl-m-phenylenediamine, or a mixture of one or more of these; the polyamine has a mass percentage concentration of 0.1-5%, Ti3C2T x The mass percentage concentration of MXene quantum dot nanoparticles is 0.001~0.1%.

8. The Ti3C2T as described in claim 7 x A method for preparing an MXene quantum dot composite polyamide reverse osmosis membrane, characterized in that, In step S3, the polyacryl chloride is one or a mixture of more than one of pyromellitic tricarboxylic acid chloride, phthaloyl chloride, isophthaloyl chloride, 1,3,5-cyclohexanetricarboxylic acid chloride, and methyl isophthalonitrile; the mass percentage concentration of the polyacryl chloride is 0.01~2.5%.

9. A Ti3C2T x MXene quantum dot composite polyamide reverse osmosis membrane, characterized in that, The reverse osmosis membrane is prepared by the preparation method described in any one of claims 1 to 8.

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