A membrane material of metal ion-induced nanoclusters and its preparation method

Abstract

This invention relates to a membrane material with metal ion-induced nanoclusters and its preparation method. In the preparation process, a solution containing polymer monomers and metal ion compounds is poured onto one side of a polymer membrane. After immersion, a metal ion-monomer coordination cluster structure is deposited on the polymer membrane. Then, a 1,3,5-benzenetriformyl chloride solution is poured onto the side of the polymer membrane where the metal ion-monomer coordination cluster structure is deposited, and an interfacial polymerization reaction is carried out. After the reaction, the membrane material is obtained through thermosetting and washing. The membrane material exhibits a rejection rate of Congo red of not less than 90.57%, a rejection rate of inorganic salts of not more than 10.82%, and a water flux of 102.55–496.31 L / m³. ‑2 h ‑ 1 bar ‑1 The present invention increases the amount of water and ion transport channels by constructing nanocluster microstructures on the membrane surface, thereby simultaneously improving the selective retention and permeation flux of the membrane material. The resulting membrane material exhibits good selective retention of Congo red and inorganic salts, and high water flux.

Description

Technical Field

[0001] This invention belongs to the field of membrane material preparation technology, and relates to a membrane material of metal ion-induced nanoclusters and its preparation method. Background Technology

[0002] Membrane separation technology, as a highly efficient separation method, is characterized by its simple operation, energy saving, environmental friendliness, and environmental friendliness. Utilizing membrane technology to separate organic matter from inorganic salts is a prerequisite and foundation for purifying organic molecules (drugs, dyes, small peptides, etc.), recovering high-value salts, and achieving zero wastewater discharge. However, the separation of organic matter and inorganic salts faces two major challenges: first, the sizes of small organic molecules and salt ions are similar, making size screening mechanisms difficult to fully achieve; second, while ensuring organic matter / salt separation, it is difficult to achieve significant breakthroughs in membrane permeate flux. Therefore, developing high-performance organic matter / salt separation membrane materials has become an important topic in the fields of membrane science, environmental science, and purification.

[0003] To this end, researchers have conducted a series of studies on membrane materials to improve the selective separation of organic matter / salt and high water flux. In 2004, a loose nanofiltration membrane that could retain organic matter and permeate salt was obtained and first used in water treatment processes (Reference 1: J. Environ. Manage. 2004, 73: 267-274). More and more studies have been designed to improve the separation performance of organic matter / salt from the perspectives of interface control, physicochemical property regulation, and pore structure design (Reference 2: Chem. Eng. J., 2022, 450: 138057; Reference 3: Sep. Purif. Technol., 2022, 283: 120163; Reference 4: J. Mater. Chem. A, 2023, 11: 2367-2376). However, the interface structure and stability of membrane materials are still difficult to control, which affects the improvement of selective separation and water flux. How to obtain membrane materials with controllable structure and stable performance by regulating the interfacial polymerization method and the microstructure morphology of the membrane surface is a key problem that urgently needs to be solved in the separation of organic matter / salt membranes.

[0004] Therefore, it is of great significance to study a metal ion-induced nanocluster membrane material and its preparation method to solve the problems existing in the prior art. Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the prior art and to provide a membrane material of metal ion-induced nanoclusters and its preparation method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a metal ion-induced nanocluster membrane material involves pouring a solution containing polymer monomers and metal ion compounds onto one side of a polymer membrane, immersing it, and depositing a metal ion-monomer coordination cluster structure on the polymer membrane. After immersion, the solution is poured out, rinsed with deionized water to remove unreacted ions, and then a 1,3,5-benzenetriformyl chloride solution is poured onto one side of the polymer membrane to deposit the metal ion-monomer coordination cluster structure for interfacial polymerization. After the reaction, the membrane is thermosetting and washed with water to obtain the metal ion-induced nanocluster membrane material.

[0008] The polymer monomer is a compound containing an amino group.

[0009] As a preferred technical solution:

[0010] The preparation method of a metal ion-induced nanocluster membrane material as described above, wherein the polymer membrane includes a base membrane and a support membrane, and the support membrane is formed by vacuum filtering polypyrrole-coated bacterial cellulose onto the base membrane.

[0011] The preparation method of a metal ion-induced nanocluster membrane material as described above, wherein the substrate membrane is a polytetrafluoroethylene filter membrane, an organic nylon filter membrane, a polypropylene filter membrane, or a polyvinylidene fluoride filter membrane.

[0012] The method for preparing a metal ion-induced nanocluster membrane material as described above has an effective substrate membrane area of ​​9.621 cm². 2 The amount of polypyrrole-coated bacterial cellulose used is 20-60 mg.

[0013] The method for preparing a metal ion-induced nanocluster membrane material as described above uses aniline, pyrrole, or dopamine as the polymer monomer and cobalt nitrate, zinc nitrate, ferric nitrate, copper nitrate, cobalt chloride, zinc chloride, ferric chloride, or copper chloride as the metal ion compound.

[0014] The method for preparing a metal ion-induced nanocluster membrane material as described above uses a mixture of ethanol and water (volume ratio of ethanol to water is 2:5) as the solvent in the solution containing polymer monomers and metal ion compounds; the mass percentage concentration of polymer monomers in the solution containing polymer monomers and metal ion compounds is 0.05-1.50%, and the concentration of metal ions is 0.025-0.2M.

[0015] The method for preparing a metal ion-induced nanocluster membrane material as described above further includes a solution containing polymer monomers and metal ion compounds containing piperazine, wherein the mass percentage concentration of piperazine does not exceed 0.50%.

[0016] In the preparation method of the metal ion-induced nanocluster membrane material described above, the mass percentage concentration of the 1,3,5-benzenetriformyl chloride solution is 0.05-0.4%.

[0017] The preparation method of the metal ion-induced nanocluster membrane material as described above has a thermal curing temperature of 50–70°C and a thermal curing time of 10–20 min.

[0018] The present invention also provides a metal ion-induced nanocluster membrane material prepared by the method described in any of the preceding claims, wherein the metal ion-induced nanocluster membrane material has a rejection rate of Congo red of not less than 90.57%, a rejection rate of inorganic salts of not more than 10.82%, and a water flux of 102.55–496.31 L m⁻² h⁻¹ bar. -1 .

[0019] The principle of this invention is as follows:

[0020] Inspired by coordination chemistry theory, taking metal-organic frameworks as an example, metal ions and organic ligands provide coordination connections to form porous materials with stable and tunable (sub)nanopore structures. If metal ions are introduced into an aqueous interfacial polymerization system, they form metal-ion-centered nanoclusters through coordination with small organic monomers. This allows for the control of interfacial amide reactions while simultaneously creating membrane surfaces with unique microstructures. By utilizing steric hindrance and the disorder of polyamide molecular weight, more nanochannels can be constructed, resulting in membrane materials with high water flux and selective separation performance, better meeting the needs of organic matter / salt separation applications.

[0021] This invention constructs nanocluster microstructures on the functional layer of a membrane surface by coordinating metal ions with polymer monomers or metal ions with polymer monomers and piperazine. This structure is generated in situ during the preparation process, avoiding problems of uneven dispersion and insufficient stability. The formation of the nanocluster microstructure alters the polymerization process and rate of the polyamide at the interface. Firstly, it manifests in changes to the surface microstructure morphology. The spherical stacking of the nanoclusters creates undulations on the originally flat polyamide surface, forming undulating "peaks and valleys" that improve water flow and increase the contact area between the membrane surface and water during separation, thus enhancing selective separation and water flux. Secondly, the presence of clusters creates nano-defect pores in the polyamide network. These pores are formed due to steric hindrance generated during the coordination of metal ions with monomers or instability caused by interactions between clusters. These newly added nano-defect pores significantly reduce the mass transfer resistance of water / salt transport and selectively block dyes, facilitating selective separation of dyes / salts and rapid water flux. The resulting membrane material achieves a water flux of 496.31 L / m³. -2 h -1 bar -1The membrane material exhibits a rejection rate of no less than 90.57% for Congo red and no more than 10.82% for inorganic salts, effectively achieving the separation of organic dyes and inorganic salts. Furthermore, the preparation method of this membrane material is simple and easy to control, showing promising prospects for large-scale preparation and application.

[0022] Beneficial effects:

[0023] (1) A method for preparing a metal ion-induced nanocluster membrane material according to the present invention involves constructing a metal ion-monomer coordination cluster structure on the membrane surface. This structure utilizes the defect pores formed by steric hindrance to increase the amount of water and ion transport channels, thereby simultaneously improving the selective retention and permeation flux of the membrane material.

[0024] (2) The metal ion-induced nanocluster membrane material of the present invention has good retention effect on Congo red and inorganic salts, high water flux, and has broad application prospects in the field of zero discharge and resource utilization of high salinity wastewater. Attached Figure Description

[0025] Figure 1 This is a surface morphology diagram of the metal ion-induced nanoclusters membrane material in Example 5;

[0026] Figure 2 The particle size distribution diagrams are for the metal ion-induced formation of aniline and pyrrole nanoclusters in Examples 1 and 2. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0028] The testing methods for the performance indicators involved in the embodiments and comparative examples of this invention are as follows:

[0029] Prior to testing, all membranes were filtered through pure water until the water flux stabilized. Membrane permeability was recorded by measuring the amount of water collected at transmembrane pressures ranging from 0.4 to 1 bar. Dye rejection performance was evaluated by measuring the dye concentration before and after filtration using absorbance measurements. High-salt wastewater and high-salt organic wastewater experiments were simulated by preparing salt solutions and dye / salt mixtures, and the change in salt concentration in the solution was measured by testing the solution conductivity. Cross-flow filtration was used to analyze the separation performance of the composite membrane for dyes and dye / salt mixtures. Cross-flow filtration, a common filtration method, uses pressure as the driving force to achieve the separation process. The following are the formulas for calculating rejection rate and water flux:

[0030] Retention rate R (%): Calculated using the following formula:

[0031]

[0032] Where C0 is the dye concentration before filtration, and C is the dye concentration before and after filtration;

[0033] Water flux J (L m⁻²h⁻¹bar⁻¹): Calculated using the following formula:

[0034]

[0035] Where V is the volume of permeate water, A is the effective membrane area, ΔP is the transmembrane pressure, and Δt is the operating time.

[0036] The sources of some material information in this invention are as follows:

[0037] Polyvinylidene fluoride membrane: Manufacturer: Jinteng, membrane diameter is 50 mm, pore size is 0.22 micrometers.

[0038] Polytetrafluoroethylene membrane: Manufacturer: Jinteng, membrane diameter is 50 mm, pore size is 0.22 micrometers.

[0039] Pyrrole: Manufacturer: Aladdin, CAS No.: 109-97-7.

[0040] Aniline: Manufacturer: Aladdin, CAS No.: 62-53-3.

[0041] Dopamine hydrochloride: Manufacturer: Aladdin, CAS No.: 62-31-7.

[0042] Cobalt nitrate, hexahydrate: Manufacturer: Aladdin, CAS No.: 10026-22-9.

[0043] Zinc chloride: Manufacturer: Aladdin, CAS No.: 7646-85-7.

[0044] Copper nitrate, trihydrate: Manufacturer: Aladdin, CAS No.: 10031-43-3.

[0045] Sodium sulfate: Manufacturer: Aladdin, CAS No.: 7757-82-6.

[0046] Congo Red: Manufacturer: Aladdin, CAS No.: 573-58-0.

[0047] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0048] Example 1

[0049] A method for preparing a membrane material with metal ion-induced nanoclusters, the specific steps of which are as follows:

[0050] (1) Preparation of raw materials:

[0051] Polymer monomer: aniline;

[0052] Metal ionic compound: cobalt nitrate;

[0053] Polymer membrane: including membranes with an effective area of ​​9.621 cm² 2 The polyvinylidene fluoride substrate membrane and the support membrane formed by vacuum filtering polypyrrole-coated bacterial cellulose onto the substrate membrane; the amount of polypyrrole-coated bacterial cellulose used is 40 mg;

[0054] (2) Add the polymer monomer, piperazine and metal ion compound to a mixture of ethanol and water in a volume ratio of 2:5 to obtain a solution containing the polymer monomer, piperazine and metal ion compound.

[0055] In a solution containing polymer monomers, piperazine, and metal ion compounds, the mass percentage concentration of polymer monomers is 1.50%, the mass percentage concentration of piperazine is 0.175%, and the concentration of metal ions is 0.01 M.

[0056] (3) Pour a solution containing polymer monomers and metal ion compounds onto one side of the polymer membrane, soak it for 10 minutes, and then deposit it on the polymer membrane to form a metal ion-monomer coordination cluster structure.

[0057] (4) A hexane solution of 1,3,5-benzenetricarboxyl chloride with a mass percentage concentration of 0.1% was poured onto one side of the polymer membrane to deposit a metal ion-monomer coordination cluster structure, and an interfacial polymerization reaction was carried out. After the reaction, the membrane was heat-cured at 60°C for 10 min and washed with water to obtain a metal ion-induced nanocluster membrane material.

[0058] The resulting metal ion-induced nanocluster membrane material exhibited a 93.46% rejection rate for 10 mg / L Congo red and a 10.82% rejection rate for 0.5 g / L Na₂SO₄ aqueous solution at 25 °C and 1 bar, with a water flux of 130.65 L m⁻²h⁻¹bar. -1 .

[0059] like Figure 2 The figure shows the particle size distribution of the mixture of aniline, piperazine and cobalt nitrate solution, with an average particle size of 66.00 nm.

[0060] Comparative Example 1

[0061] A method for preparing a membrane material of metal ion-induced nanoclusters is basically the same as in Example 1, except that metal ion compounds are not added in step (2).

[0062] The resulting metal ion-induced nanocluster membrane material exhibited a 91.68% rejection rate for 10 mg / L Congo red and an 89.38% rejection rate for 0.5 g / L Na₂SO₄ aqueous solution at 25 °C and 1 bar, with a water flux of 16.94 L m⁻² h⁻¹ bar. -1 .

[0063] Comparing Comparative Example 1 and Example 1, it can be found that Comparative Example 1 has a large rejection rate for Congo Red and Na2SO4, but a very small water flux. This is because cobalt metal ions were added in Example 1. Under the coordination effect of metal ions, the polymer monomer and piperazine form a cluster structure. During the polyamide polymerization process, more defect structures are generated due to the steric hindrance effect, and a relatively uniform and regular morphological structure is formed on the surface. The change in the microstructure of the membrane surface has greatly improved its selective separation of dyes and salts and water flux.

[0064] Example 2

[0065] A method for preparing a membrane material with metal ion-induced nanoclusters, the specific steps of which are as follows:

[0066] (1) Preparation of raw materials:

[0067] Polymer monomer: pyrrole;

[0068] Metal ionic compound: cobalt nitrate;

[0069] Polymer membrane: including membranes with an effective area of ​​9.621 cm² 2 The polyvinylidene fluoride substrate membrane and the support membrane formed by vacuum filtering polypyrrole-coated bacterial cellulose onto the substrate membrane; the amount of polypyrrole-coated bacterial cellulose used is 40 mg;

[0070] (2) Add the polymer monomer, piperazine and metal ion compound to a mixture of ethanol and water in a volume ratio of 2:5 to obtain a solution containing the polymer monomer, piperazine and metal ion compound.

[0071] In a solution containing polymer monomers, piperazine, and metal ion compounds, the mass percentage concentration of polymer monomers is 0.15%, the mass percentage concentration of piperazine is 0.175%, and the concentration of metal ions is 0.05 M.

[0072] (3) Pour a solution containing polymer monomers and metal ion compounds onto one side of the polymer membrane, soak it for 10 minutes, and then deposit it on the polymer membrane to form a metal ion-monomer coordination cluster structure.

[0073] (4) A hexane solution of 1,3,5-benzenetricarboxyl chloride with a mass percentage concentration of 0.1% was poured onto one side of the polymer membrane to deposit a metal ion-monomer coordination cluster structure, and an interfacial polymerization reaction was carried out. After the reaction, the membrane was heat-cured at 60°C for 10 min and washed with water to obtain a metal ion-induced nanocluster membrane material.

[0074] The resulting metal ion-induced nanocluster membrane material exhibited a 90.57% rejection rate for 10 mg / L Congo red and a 10.66% rejection rate for 0.5 g / L Na₂SO₄ aqueous solution at 25 °C and 1 bar, with a water flux of 186.15 L m⁻² h⁻¹ bar. -1 .

[0075] like Figure 2 The figure shows the particle size distribution of the mixture of pyrrole, piperazine and cobalt nitrate ion solution, with an average particle size of 71.45 nm.

[0076] Comparative Example 2

[0077] A method for preparing a membrane material of metal ion-induced nanoclusters is basically the same as in Example 2, except that metal ion compounds are not added in step (2).

[0078] The resulting metal ion-induced nanocluster membrane material exhibited a 94.82% rejection rate for 10 mg / L Congo red and a 96.51% rejection rate for 0.5 g / L Na₂SO₄ aqueous solution at 25 °C and 1 bar, with a water flux of 11.53 L m⁻² h⁻¹ bar. -1 .

[0079] Comparing Comparative Example 2 and Example 2, it can be found that Comparative Example 2 has a large rejection rate for Congo Red and Na2SO4, but a very small water flux. This is because cobalt metal ions were added in Example 2. Under the coordination effect of metal ions, the polymer monomer and piperazine form a cluster structure. During the polyamide polymerization process, more defect structures are generated due to the steric hindrance effect, and a relatively uniform and regular morphological structure is formed on the surface. The change in the microstructure of the membrane surface has greatly improved its selective separation of dyes and salts and water flux.

[0080] Example 3

[0081] A method for preparing a membrane material with metal ion-induced nanoclusters, the specific steps of which are as follows:

[0082] (1) Preparation of raw materials:

[0083] Polymer monomer: Dopamine hydrochloride;

[0084] Metal ionic compound: cobalt nitrate;

[0085] Polymer membrane: including membranes with an effective area of ​​9.621 cm² 2 The polyvinylidene fluoride substrate membrane and the support membrane formed by vacuum filtering polypyrrole-coated bacterial cellulose onto the substrate membrane; the amount of polypyrrole-coated bacterial cellulose used is 40 mg;

[0086] (2) Add the polymer monomer and the metal ion compound to a mixture of ethanol and water in a volume ratio of 2:5 to obtain a solution containing the polymer monomer and the metal ion compound.

[0087] In a solution containing polymer monomers and metal ion compounds, the mass percentage concentration of polymer monomers is 0.15%, and the concentration of metal ions is 0.01M.

[0088] (3) Pour a solution containing polymer monomers and metal ion compounds onto one side of the polymer membrane, soak it for 10 minutes, and then deposit it on the polymer membrane to form a metal ion-monomer coordination cluster structure.

[0089] (4) A hexane solution of 1,3,5-benzenetricarboxyl chloride with a mass percentage concentration of 0.1% was poured onto one side of the polymer membrane to deposit a metal ion-monomer coordination cluster structure, and an interfacial polymerization reaction was carried out. After the reaction, the membrane was heat-cured at 60°C for 10 min and washed with water to obtain a metal ion-induced nanocluster membrane material.

[0090] The resulting metal ion-induced nanocluster membrane material exhibited a 94.46% rejection rate for 10 mg / L Congo red and an 8.37% rejection rate for 0.5 g / L Na₂SO₄ aqueous solution at 25 °C and 1 bar, with a water flux of 432.81 L m⁻²h⁻¹bar. -1 .

[0091] Example 4

[0092] A method for preparing a membrane material with metal ion-induced nanoclusters, the specific steps of which are as follows:

[0093] (1) Preparation of raw materials:

[0094] Polymer monomer: aniline;

[0095] Metal ionic compound: cobalt nitrate;

[0096] Polymer membrane: including membranes with an effective area of ​​9.621 cm² 2 The polyvinylidene fluoride substrate membrane and the support membrane formed by vacuum filtering polypyrrole-coated bacterial cellulose onto the substrate membrane; the amount of polypyrrole-coated bacterial cellulose used is 40 mg;

[0097] (2) Add the polymer monomer, piperazine and metal ion compound to a mixture of ethanol and water in a volume ratio of 2:5 to obtain a solution containing the polymer monomer, piperazine and metal ion compound.

[0098] In a solution containing polymer monomers, piperazine, and metal ion compounds, the mass percentage concentration of polymer monomers is 0.15%, the mass percentage concentration of piperazine is 0.0875%, and the concentration of metal ions is 0.025 M.

[0099] (3) Pour a solution containing polymer monomers and metal ion compounds onto one side of the polymer membrane, soak it for 10 minutes, and then deposit it on the polymer membrane to form a metal ion-monomer coordination cluster structure.

[0100] (4) A hexane solution of 1,3,5-benzenetricarboxyl chloride with a mass percentage concentration of 0.1% was poured onto one side of the polymer membrane to deposit a metal ion-monomer coordination cluster structure, and an interfacial polymerization reaction was carried out. After the reaction, the membrane was heat-cured at 60°C for 10 min and washed with water to obtain a metal ion-induced nanocluster membrane material.

[0101] The resulting metal ion-induced nanocluster membrane material exhibited a 95.42% rejection rate for 10 mg / L Congo red and an 8.06% rejection rate for 0.5 g / L Na₂SO₄ aqueous solution at 25 °C and 1 bar, with a water flux of 235.11 L m⁻² h⁻¹ bar. -1 .

[0102] Example 5

[0103] A method for preparing a membrane material with metal ion-induced nanoclusters, the specific steps of which are as follows:

[0104] (1) Preparation of raw materials:

[0105] Polymer monomer: Dopamine hydrochloride;

[0106] Metal ionic compound: cobalt nitrate;

[0107] Polymer membrane: including membranes with an effective area of ​​9.621 cm² 2 The polyvinylidene fluoride substrate membrane and the support membrane formed by vacuum filtering polypyrrole-coated bacterial cellulose onto the substrate membrane; the amount of polypyrrole-coated bacterial cellulose used is 40 mg;

[0108] (2) Add the polymer monomer, piperazine and metal ion compound to a mixture of ethanol and water in a volume ratio of 2:5 to obtain a solution containing the polymer monomer, piperazine and metal ion compound.

[0109] In a solution containing polymer monomers, piperazine, and metal ion compounds, the mass percentage concentration of polymer monomers is 0.30%, the mass percentage concentration of piperazine is 0.175%, and the concentration of metal ions is 0.01 M.

[0110] (3) Pour a solution containing polymer monomers and metal ion compounds onto one side of the polymer membrane, soak it for 10 minutes, and then deposit it on the polymer membrane to form a metal ion-monomer coordination cluster structure.

[0111] (4) A hexane solution of 1,3,5-benzenetricarboxyl chloride with a mass percentage concentration of 0.1% was poured onto one side of the polymer membrane to deposit a metal ion-monomer coordination cluster structure, and an interfacial polymerization reaction was carried out. After the reaction, the membrane was heat-cured at 60°C for 10 min and washed with water to obtain a metal ion-induced nanocluster membrane material.

[0112] The resulting metal ion-induced nanocluster membrane material exhibited a 93.46% rejection rate for 10 mg / L Congo red and a 9.81% rejection rate for 0.5 g / L Na₂SO₄ aqueous solution at 25 °C and 1 bar, with a water flux of 102.55 L m⁻² h⁻¹ bar. -1 .

[0113] like Figure 1 As shown, the microstructure of the film surface formed by interfacial polymerization under the action of cobalt metal ions exhibits a "peak-valley" structure with uniformly arranged clusters.

[0114] Example 6

[0115] A method for preparing a membrane material with metal ion-induced nanoclusters, the specific steps of which are as follows:

[0116] (1) Preparation of raw materials:

[0117] Polymer monomer: pyrrole;

[0118] Metal ionic compound: Zinc chloride;

[0119] Polymer membrane: including membranes with an effective area of ​​9.621 cm² 2 The polyvinylidene fluoride substrate membrane and the support membrane formed by vacuum filtering polypyrrole-coated bacterial cellulose onto the substrate membrane; the amount of polypyrrole-coated bacterial cellulose used is 40 mg;

[0120] (2) Add the polymer monomer, piperazine and metal ion compound to a mixture of ethanol and water in a volume ratio of 2:5 to obtain a solution containing the polymer monomer, piperazine and metal ion compound.

[0121] In a solution containing polymer monomers, piperazine, and metal ion compounds, the mass percentage concentration of polymer monomers is 0.05%, the mass percentage concentration of piperazine is 0.25%, and the concentration of metal ions is 0.01 M.

[0122] (3) Pour a solution containing polymer monomers and metal ion compounds onto one side of the polymer membrane, soak it for 10 minutes, and then deposit it on the polymer membrane to form a metal ion-monomer coordination cluster structure.

[0123] (4) A hexane solution of 1,3,5-benzenetricarboxyl chloride with a mass percentage concentration of 0.05% was poured onto one side of the polymer membrane to deposit a metal ion-monomer coordination cluster structure, and an interfacial polymerization reaction was carried out. After the reaction, the membrane was heat-cured at 50°C for 20 min and washed with water to obtain a metal ion-induced nanocluster membrane material.

[0124] The resulting metal ion-induced nanocluster membrane material exhibited a 98.64% rejection rate for 10 mg / L Congo red and a 10.82% rejection rate for 0.5 g / L Na₂SO₄ aqueous solution at 25 °C and 1 bar, with a water flux of 113.96 L m⁻² h⁻¹ bar. -1 .

[0125] Example 7

[0126] A method for preparing a membrane material with metal ion-induced nanoclusters, the specific steps of which are as follows:

[0127] (1) Preparation of raw materials:

[0128] Polymer monomer: aniline;

[0129] Metal ionic compound: cobalt nitrate;

[0130] Polymer membrane: including membranes with an effective area of ​​9.621 cm² 2 The polytetrafluoroethylene base membrane and the support membrane formed by vacuum filtering polypyrrole-coated bacterial cellulose onto the base membrane; the amount of polypyrrole-coated bacterial cellulose used is 40 mg;

[0131] (2) Add the polymer monomer and the metal ion compound to a mixture of ethanol and water in a volume ratio of 2:5 to obtain a solution containing the polymer monomer, piperazine and metal ion compound.

[0132] In a solution containing polymer monomers, piperazine, and metal ion compounds, the mass percentage concentration of polymer monomers is 0.20%, the mass percentage concentration of piperazine is 0.0875%, and the concentration of metal ions is 0.02 M.

[0133] (3) Pour a solution containing polymer monomers and metal ion compounds onto one side of the polymer membrane, soak it for 10 minutes, and then deposit it on the polymer membrane to form a metal ion-monomer coordination cluster structure.

[0134] (4) A hexane solution of 1,3,5-benzenetricarboxyl chloride with a mass percentage concentration of 0.2% was poured onto one side of the polymer membrane to deposit a metal ion-monomer coordination cluster structure, and an interfacial polymerization reaction was carried out. After the reaction, the membrane was heat-cured at 70°C for 10 min and washed with water to obtain a metal ion-induced nanocluster membrane material.

[0135] The resulting metal ion-induced nanocluster membrane material exhibited a 95.34% rejection rate for 10 mg / L Congo red and a 4.01% rejection rate for 0.5 g / L Na₂SO₄ aqueous solution at 25 °C and 1 bar, with a water flux of 496.31 L m⁻²h⁻¹bar. -1 .

Claims

1. A method for preparing a membrane material of metal ion-induced nanoclusters, characterized in that: A solution containing polymer monomers and metal ion compounds is poured onto one side of a polymer membrane. After immersion, a metal ion-monomer coordination cluster structure is deposited on the polymer membrane. Then, a 1,3,5-benzenetricarboxyl chloride solution is poured onto one side of the polymer membrane where the metal ion-monomer coordination cluster structure is deposited, and an interfacial polymerization reaction is carried out. After the reaction, the membrane is thermosetting and washed with water to obtain a metal ion-induced nanocluster membrane material. The polymer monomers are aniline, pyrrole, or dopamine, and the metal ion compounds are cobalt nitrate, zinc nitrate, ferric nitrate, copper nitrate, cobalt chloride, zinc chloride, ferric chloride, or copper chloride.

2. The method for preparing a metal ion-induced nanocluster membrane material according to claim 1, characterized in that, The polymer membrane includes a base membrane and a support membrane. The support membrane is formed by vacuum filtering polypyrrole-coated bacterial cellulose onto the base membrane.

3. The method for preparing a metal ion-induced nanocluster membrane material according to claim 2, characterized in that, The base membrane is a polytetrafluoroethylene filter membrane, an organic nylon filter membrane, a polypropylene filter membrane, or a polyvinylidene fluoride filter membrane.

4. The method for preparing a metal ion-induced nanocluster membrane material according to claim 2, characterized in that, The effective area of ​​the basement membrane is 9.621 cm². 2 The dosage of polypyrrole-coated bacterial cellulose is 20-60 mg.

5. The method for preparing a metal ion-induced nanocluster membrane material according to claim 1, characterized in that, The solution containing polymer monomers and metal ion compounds is a mixture of ethanol and water as solvent; the polymer monomers have a mass percentage concentration of 0.05-1.50%, and the metal ion concentration is 0.025-0.2M.

6. The method for preparing a metal ion-induced nanocluster membrane material according to claim 5, characterized in that, The solution containing polymer monomers and metal ion compounds also contains piperazine, with a mass percentage concentration of piperazine not exceeding 0.50%.

7. The method for preparing a metal ion-induced nanocluster membrane material according to claim 1, characterized in that, The mass percentage concentration of the 1,3,5-benzenetricarboxylic acid chloride solution is 0.05~0.4%.

8. The method for preparing a metal ion-induced nanocluster membrane material according to claim 1, characterized in that, The heat curing temperature is 50~70℃, and the heat curing time is 10~20min.

9. The metal ion-induced nanocluster membrane material prepared by the method according to any one of claims 1 to 8, characterized in that: The membrane material with metal ion-induced nanoclusters exhibits a retention rate of no less than 90.57% for Congo red and no more than 10.82% for inorganic salts, with a water flux ranging from 102.55 to 496.31 L / m². -2 h -1 bar -1 .

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