A fenton-like catalytic membrane based on block copolymer and preparation method and application thereof

Abstract

The application belongs to the technical field of wastewater pollutant treatment, and relates to a Fenton-like catalytic membrane based on block copolymer and a preparation method and application thereof. The preparation method is that a nano-porous block copolymer membrane is immersed in a mixed solution containing metal ions and organic ligand A to react. The nano-porous block copolymer membrane contains organic ligand B. The metal ions form coordination bonds with the organic ligand A and the organic ligand B at the same time, so that MOF is synthesized on the surface and in the pores of the nano-porous block copolymer membrane. The finally prepared Fenton-like catalytic membrane based on block copolymer is used for removing dyes in wastewater. After being used for a period of time, the permeability of the Fenton-like catalytic membrane based on block copolymer and the removal rate of the dyes are both high, and the Fenton-like catalytic membrane based on block copolymer can meet the industrial application requirements.

Description

Technical Field

[0001] This invention belongs to the field of wastewater pollutant treatment technology, specifically relating to a Fenton-like catalytic membrane based on block copolymers, its preparation method, and its application. Background Technology

[0002] The main challenge facing existing wastewater treatment plants is the increasing presence of recalcitrant compounds in wastewater, such as surfactants, dyes, personal care products, and pharmaceuticals. Conventional treatment technologies are not yet effective in removing these recalcitrant organic compounds from wastewater, inevitably releasing them into the environment and causing serious adverse effects not only on aquatic life but also on human health. To address this problem, advanced oxidation processes (AOPs) have emerged as a promising wastewater treatment technology.

[0003] Common AOPs (Activated Organic Pollutants) are mainly classified into Fenton technology, ozone oxidation technology, persulfate oxidation technology, wet oxidation technology, and supercritical water oxidation technology. Among them, Fenton oxidation technology is a mature system that can rapidly generate highly oxidizing hydroxyl radicals, making it an effective method for treating recalcitrant organic matter in wastewater. However, traditional homogeneous Fenton technology has drawbacks such as a narrow optimal pH range for the catalytic reaction, difficulty in recovering and separating the active components of the catalyst, and secondary pollution caused by the generated iron, which greatly limits its widespread application. Heterogeneous Fenton technology has a wide applicable pH range and does not produce chemical sludge, but it still cannot avoid the problems of active free radicals easily self-quenching in water and having extremely short lifespans. Therefore, researching how to improve Fenton technology is of great significance.

[0004] Membrane separation technology is a widely used and advanced technology for continuous water treatment, offering advantages such as simplicity, high efficiency, and small footprint. However, it is susceptible to fouling during operation. Preparing Fenton-like catalytic membranes by anchoring Fenton-like catalysts to the membrane surface or pores can shorten the mass transfer path of reactive oxygen species (ROS), enabling continuous and efficient catalysis of pollutants in water during membrane separation, thereby significantly improving catalytic efficiency. However, the integration of Fenton-like catalysts with the membrane can lead to the covering of Fenton catalyst active sites or catalyst blockage of membrane pores, resulting in low pollutant degradation efficiency or poor permeability of the Fenton-like catalytic membrane.

[0005] The paper (Overcoming the permeability-selectivity challenge in waterpurification using two-dimensional cobalt-functionalized vermiculite membrane. Nature Communications, 2024, 15:391.) discloses a two-dimensional cobalt-functionalized vermiculite membrane with a permeability of 122.4 L / (m²). 2 (·h·bar), pollutant removal rate is 100%.

[0006] The literature (Angstrom-confined catalytic water purification within Co-TiOxlaminar membrane nanochannel. Nature Communications, 2022, 13: 4010.) discloses a two-dimensional laminated membrane assembled from a single layer of cobalt-doped titanium dioxide nanosheets with a permeability of 131 L / (m²). 2 (·h·bar), pollutant removal rate is 100%.

[0007] The literature (Inert magnesium-doped Co3O4 spinel assembling catalytic membrane for instantaneous peroxymonosulfate activation and contaminants elimination. Chemical Engineering Journal, 2023, 477: 146987.) discloses an MCO@PES membrane fabricated by depositing inert magnesium-doped Co3O4 (MCO) onto a PES substrate through vacuum filtration, achieving a permeability of 315 L / (m²). 2 (·h·bar), the pollutant removal rate is 99.5%.

[0008] The literature (Honeycomb-like holey Co3O4 membrane triggered peroxymonosulfate activation for rapid degradation of organic contaminants. Science of the Total Environment, 2022, 814:152698.) discloses a honeycomb-like porous Co3O4 membrane with a permeability of 176 L / (m³).2 (·h·bar), pollutant removal rate is 100%.

[0009] The paper (Confining Free Radicals in Close Vicinity to Contaminants Enables Ultrafast Fenton-like Processes in the Interspacing of MoS2Membranes. Angewandte Chemie International Edition, 2019, 58(24): 8134-8138.) discloses a layered membrane made of 2D MoS2 stacks with a permeability of 152.9 L / (m²). 2 (·h·bar), pollutant removal rate is 90%.

[0010] The literature (Laminar membranes assembled by ultrathin cobalt-copper oxide nanosheets for nanoconfined catalytic degradation of contaminants. Chemical Engineering Journal, 2022, 449: 137811.) discloses a Fenton membrane with a permeability of 357 L / (m²) prepared by depositing ultrathin cobalt-copper oxide nanosheets (Co-CuONS) on the surface of a PVDF substrate membrane via vacuum filtration. 2 (·h·bar), pollutant removal rate is 100%.

[0011] The literature (Polyacrylonitrile (PAN)-induced carbon membrane with in-situ encapsulated cobalt crystal for hybrid peroxymonosulfate oxidation-filtration process: Preparation, characterization and performance evaluation. Chemical Engineering Journal, 2019, 373: 425-436.) discloses a polyacrylonitrile-induced carbon membrane with in-situ encapsulated cobalt crystal and a permeability of 140 L / (m²). 2 (·h·bar), pollutant removal rate is 100%.

[0012] The literature (Fabrication of ZIF-67@PVDF ultrafiltration membrane with improved antifouling and separation performance for dye wastewater treatment via sulfate radical enhancement. Separation and Purification Technology, 2021, 279:119755.) discloses a ZIF-67-embedded PVDF (ZIF-67@PVDF) hybrid matrix ultrafiltration membrane prepared by non-solvent-induced phase separation (NIPS) technology, with a permeability of 263.3 L / (m³). 2 (·h·bar), the pollutant removal rate was 98.9%.

[0013] The literature (PES / Fe3S4@NiO self-cleaning membrane with rapid catalysis for effective emulsion separation and dye degradation. Journal of Membrane Science, 2023, 684:121874.) discloses an ultrafiltration membrane with Fe3S4@Ni embedded in a PES hybrid matrix, prepared by solvent-inducible phase separation (NIPS) technology, exhibiting a permeability of 426 L / (m²). 2 (·h·bar), pollutant removal rate is 100%.

[0014] The literature (Ultrahigh permeance functionalized boron nitride membrane for nanoconfined heterogeneous catalysis. Chem Catalysis, 2022, 2: 550-562.) discloses a functionalized boron nitride nanosheet membrane with a permeability of 548 L / (m 2 (·h·bar), pollutant removal rate is 99%.

[0015] As can be seen from the above, the permeability of existing Fenton-like catalytic membranes is concentrated in the range of 122.4-548 L / (m²). 2 The pollutant removal rate is 90-100% (·h·bar), but the permeation performance of Fenton-like catalytic membranes is still relatively low.

[0016] Therefore, improving the bonding method between Fenton-like catalysts and membranes to enable Fenton-like catalytic membranes to have high permeability and high pollutant removal rate has become an urgent problem to be solved for heterogeneous Fenton-like catalytic membranes. Summary of the Invention

[0017] The purpose of this invention is to solve the above-mentioned problems existing in the prior art, and to provide a Fenton-like catalytic membrane based on block copolymers, its preparation method and application, which has the advantages of high permeability and high pollutant removal rate.

[0018] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0019] A method for preparing a Fenton-like catalytic membrane based on block copolymers involves immersing a nanoporous block copolymer membrane in a mixed solution containing metal ions and organic ligand A for reaction. The nanoporous block copolymer membrane contains organic ligand B, and the metal ions simultaneously form coordination bonds with organic ligand A and organic ligand B, thereby achieving the synthesis of MOFs (metal-organic frameworks) on the surface and inside the pores of the nanoporous block copolymer membrane, thus obtaining a Fenton-like catalytic membrane based on block copolymers.

[0020] As a preferred technical solution:

[0021] In the method for preparing a Fenton-like catalytic membrane based on a block copolymer as described above, the metal ion is at least one of cobalt ions, iron ions, and copper ions (e.g., metal ions are provided by cobalt nitrate and its hydrate, cobalt chloride and its hydrate, ferric chloride and its hydrate, and copper acetate and its hydrate).

[0022] In the method for preparing a Fenton-like catalytic membrane based on a block copolymer as described above, the organic ligand A is at least one of 2-methylimidazole, 1,3,5-benzenetricarboxylic acid, and 2-aminoterephthalic acid.

[0023] In the preparation method of the Fenton-like catalytic membrane based on block copolymers as described above, the organic ligand B is pyridyl, amino, carboxyl, ester, siloxy, or alkoxy.

[0024] The method for preparing a Fenton-like catalytic membrane based on block copolymers as described above involves a reaction time of 25°C and 1 hour.

[0025] In the preparation method of the Fenton-like catalytic membrane based on block copolymers as described above, the concentration of metal ions in the mixed solution is 0.01-0.06 mol / L, and the concentration of organic ligand A in the mixed solution is 0.01-0.4 mol / L.

[0026] In the preparation method of the Fenton-like catalytic membrane based on block copolymers as described above, after the reaction is completed, the nanoporous block copolymer membrane is taken out, rinsed with deionized water, and then placed in an oven to dry.

[0027] The method for preparing a Fenton-like catalytic membrane based on block copolymers, as described above, involves obtaining a nanoporous block copolymer membrane through the following steps:

[0028] (1) Add the block copolymer solution to the microfiltration membrane, rotate the microfiltration membrane with a spin coater to make the block copolymer solution uniformly coated on the surface of the microfiltration membrane, and dry to obtain a composite membrane;

[0029] (2) The composite membrane is immersed in a mixed solvent containing a good solvent and a bad solvent, and then transferred to the bad solvent to obtain a nanoporous block copolymer membrane.

[0030] In the preparation method of the Fenton-like catalytic membrane based on block copolymer as described above, in step (1), the block copolymer in the block copolymer solution is composed of block a and block b, wherein block a is polystyrene (PS), polysulfone (PSf), polyethylene (PE) or polycyclohexene carbonate (PCHC), and block b is poly(2-vinylpyridine) (P2VP), polyethylene oxide (PEO), poly(4-vinylpyridine) (P4VP), polymethyl methacrylate (PMMA), polymethyl methacrylate (PMAA), poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA), polyethylene glycol (PEG) or polylactic acid (PLA); wherein the volume of block b accounts for 1-60% of the total volume of block a and block b; and the molecular weight of the block copolymer is 5-800 kg / mol.

[0031] As described above, in the preparation method of a Fenton-like catalytic membrane based on block copolymers, in step (1), the block copolymer solution is obtained by dissolving at least one block copolymer in an organic solvent, wherein the organic solvent is at least one of acetone and chloroform, and the block copolymer content in the block copolymer solution is 1-5 wt%.

[0032] In the preparation method of the Fenton-like catalytic membrane based on block copolymer as described above, in step (2), the good solvent is at least one of acetone, chloroform, tetrahydrofuran, toluene, 1,2-dichlorobenzene and cyclohexane, and the bad solvent is at least one of methanol, ethanol, 2-propanol, acetic acid and n-hexadecane. The volume ratio of the good solvent to the bad solvent is 1 / 9-5 / 5, the soaking time is 1-60s, and the soaking temperature is 25℃.

[0033] The present invention also provides a Fenton-like catalytic membrane based on block copolymers, which is prepared by the preparation method described in any of the preceding claims; the Fenton-like catalytic membrane based on block copolymers has a thickness of 600-800 nm, an average pore size between 20-78 nm, and good hydrophilicity. This highly porous Fenton-like catalytic membrane provides a structural basis for the high permeability and high removal rate of dye solutions.

[0034] This invention also provides the application of the block copolymer-based Fenton-like catalytic membrane described above for removing dyes from wastewater; after a period of use, the permeability of the block copolymer-based Fenton-like catalytic membrane remains as high as 736-3070 L / (m³). 2 Even at 0.1 bar (·h·bar), the dye removal rate is still as high as 89.6-100%, and after a period of use, it can be filtered for 2 hours at 0.1 bar and 25°C.

[0035] Beneficial effects:

[0036] (1) In this invention, MOF is synthesized on the surface and inside the pores of a nanoporous block copolymer membrane by forming coordination bonds between metal ions and organic ligands, thus obtaining a Fenton-like catalytic membrane based on block copolymer with an average pore size between 20-78 nm and excellent catalytic performance.

[0037] (2) The block copolymer-based Fenton-like catalytic membrane provided by this invention is applied to the Fenton catalytic treatment of wastewater. The nanocatalyst can rapidly catalyze oxidants (such as hydrogen peroxide, potassium persulfate, etc.) to generate active oxygen such as hydroxyl radicals, sulfate radicals, or singlet oxygen. Due to the confinement effect of the nanopores with an average pore size of 20-78 nm, active oxygen is maintained at a high concentration level within the membrane pores. Pollutants are confined within the effective diffusion range of active oxygen, thereby achieving efficient degradation of recalcitrant organic pollutants. Compared with ordinary heterogeneous Fenton technology, this invention avoids the problem of catalyst aggregation. The confined space improves the life cycle and utilization efficiency of active oxygen, thereby greatly improving the removal rate of pollutants. Moreover, the nanopores with an average pore size of 20-78 nm effectively ensure the permeability of the catalytic membrane. When used to remove dyes from wastewater, the permeability of the block copolymer-based Fenton-like catalytic membrane is still as high as 736-3070 L / (m²) after a period of use. 2 Even at ·h·bar), the dye removal rate remains as high as 89.6-100%.

[0038] (3) The preparation method provided by the present invention is simple, easy to mass-produce, and can meet the needs of industrial applications. Attached Figure Description

[0039] Figure 1 These are scanning electron microscope (SEM) images of the surface of the nanoporous block copolymer membrane and the Fenton-like catalytic membrane based on the block copolymer in Example 1 of the present invention, wherein (a) is a scanning electron microscope (SEM) image of the surface of the nanoporous block copolymer membrane and (b) is a scanning electron microscope (SEM) image of the surface of the Fenton-like catalytic membrane based on the block copolymer.

[0040] Figure 2These are cross-sectional scanning electron microscope (SEM) images of the nanoporous block copolymer membrane and the Fenton-like catalytic membrane based on the block copolymer according to Example 1 of the present invention, wherein (a) is a cross-sectional SEM image of the nanoporous block copolymer membrane and (b) is a cross-sectional SEM image of the Fenton-like catalytic membrane based on the block copolymer.

[0041] Figure 3 These are X-ray diffraction patterns of the nanoporous block copolymer membrane and the Fenton-like catalytic membrane based on the block copolymer in Example 1 of the present invention, wherein (a) is the nanoporous block copolymer membrane and (b) is the Fenton-like catalytic membrane based on the block copolymer.

[0042] Figure 4 This is a graph showing the detection results of dye oxidative degradation using a block copolymer-based Fenton-like catalytic membrane according to Example 1 of the present invention. Detailed Implementation

[0043] 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.

[0044] The calculation or testing methods for the relevant performance in the following embodiments and comparative examples are as follows:

[0045] (1) Permeability of Fenton-like catalytic membrane and removal rate of Rhodamine B

[0046] The formula for calculating the permeability (J) of a Fenton-like catalytic membrane is as follows: In the formula, V is the volume (L) of dye solution permeating from the catalytic membrane within time T (h), and A is the effective area of ​​the membrane (m²). 2 P is 0.1 (bar);

[0047] The formula for calculating the removal rate (r) of Rhodamine B is: In the formula, C0 is the concentration of the dye solution before filtration, and Cp is the concentration of the dye solution after filtration. Both are calculated using Thermo Fisher Scientific's Evolution... TM Measured by One UV-Vis spectrophotometer.

[0048] (2) Scanning electron microscopy (SEM) test

[0049] The surface and cross-section of the nanoporous block copolymer membrane and the Fenton-like catalytic membrane based on the block copolymer were observed using a field emission scanning electron microscope (SU8010, Hitachi, Japan).

[0050] (3) X-ray diffraction (XRD) test

[0051] X-ray diffractometer (Bruker D8, Germany) was used to analyze nanoporous block copolymer membranes and Fenton-like catalytic membranes based on block copolymers.

[0052] Example 1

[0053] A method for preparing a Fenton-like catalytic membrane based on block copolymers, comprising the following specific steps:

[0054] (1) Preparation of raw materials;

[0055] Block copolymer: PS-b-P4VP, P4VP molecular weight is 20 kg / mol, PS-b-P4VP molecular weight is 140 kg / mol;

[0056] Organic solvent: chloroform;

[0057] Block copolymer solution: The content of block copolymer is 2wt%. The preparation process is as follows: after dissolving the block copolymer in an organic solvent, it is filtered with a polytetrafluoroethylene (PTFE) filter with an average pore size of 0.45μm.

[0058] Pure water;

[0059] Sodium polymethacrylate (NaPMA) solution: 15 wt% concentration, solvent is pure water;

[0060] Microfiltration membrane: made of polyvinylidene fluoride (PVDF), with an average pore size of 0.22 μm, circular shape, and a diameter of 25 mm;

[0061] Good solvent: Toluene;

[0062] Unsuitable solvent: Methanol;

[0063] Mixed solvent: composed of a good solvent and a bad solvent in a volume ratio of 35:65;

[0064] Metal salt: Cobalt nitrate hexahydrate;

[0065] Organic ligand A: 2-methylimidazole;

[0066] The mixed solution consists of a metal salt, organic ligand A, and pure water. The concentration of the metal ion is 0.06 mol / L, and the concentration of organic ligand A in the mixed solution is 0.4 mol / L.

[0067] (2) Preparation of nanoporous block copolymer membranes;

[0068] First, 75 μL of NaPMA solution was dropped onto a glass slide, and then the microfiltration membrane was placed on the surface of the NaPMA solution. After standing for 3 minutes, 450 μL of block copolymer solution was dropped onto the microfiltration membrane. The solution was then coated onto the surface of the microfiltration membrane using a spin coater at a rotation speed of 3000 rpm and a rotation time of 30 seconds to obtain a composite membrane.

[0069] The composite membrane was then immersed in pure water to remove the NaPMA filling, and then treated in a vacuum oven at 33.6 kPa and 110°C for 20 minutes, and then gradually reduced to 30°C at a cooling rate of 1°C per minute.

[0070] Next, the composite membrane is immersed in the mixed solvent for 3 seconds at a temperature of 25°C.

[0071] Finally, the composite membrane was immediately transferred to methanol, a poor solvent, to terminate pore formation. The composite membrane was then removed and allowed to air dry to obtain a nanoporous block copolymer membrane. The surface scanning electron microscope results of this nanoporous block copolymer membrane are shown below. Figure 1 As shown in (a), the cross-sectional scanning electron microscope results are as follows: Figure 2 As shown in (a), the X-ray diffraction results are as follows: Figure 3 As shown in (a);

[0072] (3) Preparation of Fenton-like catalytic membranes based on block copolymers;

[0073] The nanoporous block copolymer membrane obtained in step (2) was immersed in 50 mL of mixed solution for reaction at 25 °C for 1 h. The pyridinyl group of the nanoporous block copolymer membrane served as organic ligand B for the metal ions. The metal ions simultaneously formed coordination bonds with both the pyridinyl group and organic ligand A, thus achieving the synthesis of MOF on the surface and within the pores of the nanoporous block copolymer membrane, obtaining a MOF-functionalized Fenton-like catalytic membrane. The MOF-functionalized Fenton-like catalytic membrane was removed, rinsed with deionized water, and dried in an oven with a vacuum degree <100 Pa to obtain the block copolymer-based Fenton-like catalytic membrane with an average pore size of 69.7 nm. The surface scanning electron microscope results of this block copolymer-based Fenton-like catalytic membrane are shown below. Figure 1 As shown in (b), the cross-sectional scanning electron microscope results are as follows: Figure 2 As shown in (b), the X-ray diffraction results are as follows: Figure 3 As shown in (b);

[0074] Figure 1 Compared with (a), the number of pores in (b) is significantly reduced, and the average pore size also decreases from 78 nm to 72 nm, indicating that the nanoporous block copolymer membrane successfully loaded MOF.

[0075] Figure 2In comparison with (a), the diameter of the internal pores in (b) is reduced, indicating that the MOF was successfully embedded inside the pores of the nanoporous block copolymer membrane.

[0076] Figure 3 In comparison with (a), the diffraction peaks (001), (002), (112), (022), (013), (222), (114), and (1134) in (b) indicate that MOF was successfully synthesized on the nanoporous block copolymer film.

[0077] The aforementioned Fenton-like catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0078] First, potassium persulfate was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 7, resulting in a final concentration of 0.1 g / L, to obtain the dye solution.

[0079] The Fenton-like catalytic membrane prepared in Example 1 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area). 2 In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0080] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the Fenton-like catalytic membrane was then collected. The permeability of the Fenton-like catalytic membrane and the removal rate of Rhodamine B were calculated after testing. The results showed that the permeability of the Fenton-like catalytic membrane was still as high as 1866 L / (m³). 2 Even with ·h·bar), the removal rate of Rhodamine B remains as high as 99.9% (dye detection of dye solution as shown in h·bar). Figure 4 (As shown).

[0081] Comparative Example 1

[0082] A method for preparing a catalytic membrane differs from Example 1 in that step (2) is omitted, and in step (3), a microfiltration membrane (same as in Example 1) is directly used instead of a nanoporous block copolymer membrane to be immersed in a mixed solution for reaction to obtain a catalytic membrane.

[0083] The aforementioned catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0084] First, potassium persulfate was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 7, resulting in a final concentration of 0.1 g / L, to obtain the dye solution.

[0085] The catalytic membrane prepared in Comparative Example 1 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area).2 In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0086] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the catalytic membrane was collected, and the permeability of the catalytic membrane and the removal rate of Rhodamine B were calculated. The results showed that the permeability of the catalytic membrane was 216.8 L / (m²). 2 The removal rate of Rhodamine B was 92.3% (·h·bar).

[0087] Compared with Example 1, the permeation performance of the catalytic membrane prepared in Comparative Example 1 was significantly reduced. This is because the lack of coordination between the block copolymer and metal ions resulted in the formation of a large amount of ZIF-67 on the surface of the microfiltration membrane without block copolymer, which blocked the pores of the microfiltration membrane and caused a significant decrease in the permeation performance of the catalytic membrane.

[0088] Example 2

[0089] A method for preparing a Fenton-like catalytic membrane based on block copolymers, comprising the following specific steps:

[0090] (1) Preparation of raw materials;

[0091] Block copolymer: PS-b-P4VP, P4VP molecular weight is 20 kg / mol, PS-b-P4VP molecular weight is 140 kg / mol;

[0092] Organic solvent: chloroform;

[0093] Block copolymer solution: The content of block copolymer is 2wt%. The preparation process is as follows: after dissolving the block copolymer in an organic solvent, it is filtered with a PTFE filter with an average pore size of 0.45μm.

[0094] Pure water;

[0095] NaPMA solution: concentration 15wt%, solvent is pure water;

[0096] Microfiltration membrane: made of PVDF, with an average pore size of 0.22μm, circular shape, and a diameter of 25mm;

[0097] Good solvent: Toluene;

[0098] Unsuitable solvent: Methanol;

[0099] Mixed solvent: composed of a good solvent and a bad solvent in a volume ratio of 35:65;

[0100] Metal salt: Cobalt nitrate hexahydrate;

[0101] Organic ligand A: 2-methylimidazole;

[0102] The mixed solution consists of a metal salt, organic ligand A, and pure water. The concentration of the metal ion is 0.06 mol / L, and the concentration of organic ligand A in the mixed solution is 0.4 mol / L.

[0103] (2) Preparation of nanoporous block copolymer membranes;

[0104] First, 75 μL of NaPMA solution was dropped onto a glass slide, and then the microfiltration membrane was placed on the surface of the NaPMA solution. After standing for 3 minutes, 450 μL of block copolymer solution was dropped onto the microfiltration membrane. The solution was then coated onto the surface of the microfiltration membrane using a spin coater at a rotation speed of 3000 rpm and a rotation time of 30 seconds to obtain a composite membrane.

[0105] The composite membrane was then immersed in pure water to remove the NaPMA filling, and then treated in a vacuum oven at 33.6 kPa and 110°C for 20 minutes, and then gradually reduced to 30°C at a cooling rate of 1°C per minute.

[0106] Next, the composite membrane is immersed in the mixed solvent for 1 second at a temperature of 25°C.

[0107] Finally, the composite membrane was immediately transferred to the undesirable solvent methanol to terminate pore formation. The composite membrane was then removed and naturally dried to obtain a nanoporous block copolymer membrane.

[0108] (3) Preparation of Fenton-like catalytic membranes based on block copolymers;

[0109] The nanoporous block copolymer membrane obtained in step (2) was immersed in 50 mL of mixed solution for reaction at 25 °C for 1 h. The nanoporous block copolymer membrane contains pyridine groups as organic ligands B for metal ions. The metal ions simultaneously form coordination bonds with pyridine groups and organic ligands A, thereby achieving the synthesis of MOF on the surface and inside the pores of the nanoporous block copolymer membrane, and obtaining a MOF-functionalized Fenton-like catalytic membrane. The MOF-functionalized Fenton-like catalytic membrane was taken out, rinsed with deionized water, and dried in an oven with a vacuum degree <100 Pa to obtain the block copolymer-based Fenton-like catalytic membrane with an average pore size of 64.3 nm.

[0110] The aforementioned Fenton-like catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0111] First, potassium persulfate was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 7, resulting in a final concentration of 0.1 g / L, to obtain the dye solution.

[0112] The Fenton-like catalytic membrane prepared in Example 2 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area). 2 In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0113] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the Fenton-like catalytic membrane was then collected. The permeability of the Fenton-like catalytic membrane and the removal rate of Rhodamine B were calculated after testing. The results showed that the permeability of the Fenton-like catalytic membrane was still as high as 1371 L / (m³). 2 Even at 100% h·bar, the removal rate of Rhodamine B remained as high as 100%.

[0114] Example 3

[0115] A method for preparing a Fenton-like catalytic membrane based on block copolymers, comprising the following specific steps:

[0116] (1) Preparation of raw materials;

[0117] Block copolymer: PS-b-P4VP, P4VP molecular weight is 20 kg / mol, PS-b-P4VP molecular weight is 140 kg / mol;

[0118] Organic solvent: chloroform;

[0119] Block copolymer solution: The content of block copolymer is 2wt%. The preparation process is as follows: after dissolving the block copolymer in an organic solvent, it is filtered with a PTFE filter with an average pore size of 0.45μm.

[0120] Pure water;

[0121] NaPMA solution: concentration 15wt%, solvent is pure water;

[0122] Microfiltration membrane: made of polyethersulfone (PES), with an average pore size of 0.22 μm, circular shape, and a diameter of 25 mm;

[0123] Good solvent: Toluene;

[0124] Unsuitable solvent: Methanol;

[0125] Mixed solvent: composed of a good solvent and a bad solvent in a volume ratio of 35:65;

[0126] Metal salt: Cobalt chloride hexahydrate;

[0127] Organic ligand A: 2-methylimidazole;

[0128] The mixed solution consists of a metal salt, organic ligand A, and pure water. The concentration of the metal ion is 0.06 mol / L, and the concentration of organic ligand A in the mixed solution is 0.4 mol / L.

[0129] (2) Preparation of nanoporous block copolymer membranes;

[0130] First, 75 μL of NaPMA solution was dropped onto a glass slide, and then the microfiltration membrane was placed on the surface of the NaPMA solution. After standing for 3 minutes, 450 μL of block copolymer solution was dropped onto the microfiltration membrane. The solution was then coated onto the surface of the microfiltration membrane using a spin coater at a rotation speed of 3000 rpm and a rotation time of 30 seconds to obtain a composite membrane.

[0131] The composite membrane was then immersed in pure water to remove the NaPMA filling, and then treated in a vacuum oven at 33.6 kPa and 110°C for 20 minutes, and then gradually reduced to 30°C at a cooling rate of 1°C per minute.

[0132] Next, the composite membrane is immersed in the mixed solvent for 9 seconds at a temperature of 25°C.

[0133] Finally, the composite membrane was immediately transferred to the undesirable solvent methanol to terminate pore formation. The composite membrane was then removed and naturally dried to obtain a nanoporous block copolymer membrane.

[0134] (3) Preparation of Fenton-like catalytic membranes based on block copolymers;

[0135] The nanoporous block copolymer membrane obtained in step (2) was immersed in 50 mL of mixed solution for reaction at 25 °C for 1 h. The nanoporous block copolymer membrane contains pyridine groups as organic ligands B for metal ions. The metal ions simultaneously form coordination bonds with pyridine groups and organic ligands A, thereby achieving the synthesis of MOF on the surface and inside the pores of the nanoporous block copolymer membrane, and obtaining a MOF-functionalized Fenton-like catalytic membrane. The MOF-functionalized Fenton-like catalytic membrane was removed, rinsed with deionized water, and dried in an oven with a vacuum degree <100 Pa to obtain the block copolymer-based Fenton-like catalytic membrane with an average pore size of 77 nm.

[0136] The aforementioned Fenton-like catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0137] First, potassium persulfate was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 7, resulting in a final concentration of 0.1 g / L, to obtain the dye solution.

[0138] The Fenton-like catalytic membrane prepared in Example 3 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area). 2In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0139] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the Fenton-like catalytic membrane was then collected. The permeability of the Fenton-like catalytic membrane and the removal rate of Rhodamine B were calculated after testing. The results showed that the permeability of the Fenton-like catalytic membrane was still as high as 3070 L / (m³). 2 Even at ·h·bar), the removal rate of Rhodamine B remained as high as 89.6%.

[0140] Example 4

[0141] A method for preparing a Fenton-like catalytic membrane based on block copolymers, comprising the following specific steps:

[0142] (1) Preparation of raw materials;

[0143] Block copolymer: PS-b-P4VP, P4VP molecular weight is 20 kg / mol, PS-b-P4VP molecular weight is 140 kg / mol;

[0144] Organic solvent: chloroform;

[0145] Block copolymer solution: The content of block copolymer is 2wt%. The preparation process is as follows: after dissolving the block copolymer in an organic solvent, it is filtered with a PTFE filter with an average pore size of 0.45μm.

[0146] Pure water;

[0147] NaPMA solution: concentration 15wt%, solvent is pure water;

[0148] Microfiltration membrane: made of PVDF, with an average pore size of 0.22μm, circular shape, and a diameter of 25mm;

[0149] Good solvent: Toluene;

[0150] Unsuitable solvent: Methanol;

[0151] Mixed solvent: composed of a good solvent and a poor solvent in a volume ratio of 30:70;

[0152] Metal salt: Cobalt nitrate hexahydrate;

[0153] Organic ligand A: 2-methylimidazole;

[0154] The mixed solution consists of a metal salt, organic ligand A, and pure water. The concentration of the metal ion is 0.06 mol / L, and the concentration of organic ligand A in the mixed solution is 0.4 mol / L.

[0155] (2) Preparation of nanoporous block copolymer membranes;

[0156] First, 75 μL of NaPMA solution was dropped onto a glass slide, and then the microfiltration membrane was placed on the surface of the NaPMA solution. After standing for 3 minutes, 450 μL of block copolymer solution was dropped onto the microfiltration membrane. The solution was then coated onto the surface of the microfiltration membrane using a spin coater at a rotation speed of 3000 rpm and a rotation time of 30 seconds to obtain a composite membrane.

[0157] The composite membrane was then immersed in pure water to remove the NaPMA filling, and then treated in a vacuum oven at 33.6 kPa and 110°C for 20 minutes, and then gradually reduced to 30°C at a cooling rate of 1°C per minute.

[0158] Next, the composite membrane is immersed in the mixed solvent for 3 seconds at a temperature of 25°C.

[0159] Finally, the composite membrane was immediately transferred to the undesirable solvent methanol to terminate pore formation. The composite membrane was then removed and naturally dried to obtain a nanoporous block copolymer membrane.

[0160] (3) Preparation of Fenton-like catalytic membranes based on block copolymers;

[0161] The nanoporous block copolymer membrane obtained in step (2) was immersed in 50 mL of mixed solution for reaction at 25 °C for 1 h. The nanoporous block copolymer membrane contains pyridine groups as organic ligands B for metal ions. The metal ions simultaneously form coordination bonds with pyridine groups and organic ligands A, thereby achieving the synthesis of MOF on the surface and inside the pores of the nanoporous block copolymer membrane, and obtaining a MOF-functionalized Fenton-like catalytic membrane. The MOF-functionalized Fenton-like catalytic membrane was taken out, rinsed with deionized water, and dried in an oven with a vacuum degree <100 Pa to obtain the block copolymer-based Fenton-like catalytic membrane with an average pore size of 56.1 nm.

[0162] The aforementioned Fenton-like catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0163] First, potassium persulfate was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 7, resulting in a final concentration of 0.1 g / L, to obtain the dye solution.

[0164] The Fenton-like catalytic membrane prepared in Example 4 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area). 2 In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0165] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the Fenton-like catalytic membrane was then collected. The permeability of the Fenton-like catalytic membrane and the removal rate of Rhodamine B were calculated after testing. The results showed that the permeability of the Fenton-like catalytic membrane was still as high as 1335 L / (m³). 2 Even at 100% h·bar, the removal rate of Rhodamine B remained as high as 100%.

[0166] Example 5

[0167] A method for preparing a Fenton-like catalytic membrane based on block copolymers, comprising the following specific steps:

[0168] (1) Preparation of raw materials;

[0169] Block copolymer: PS-b-P4VP, P4VP molecular weight is 20 kg / mol, PS-b-P4VP molecular weight is 140 kg / mol;

[0170] Organic solvent: chloroform;

[0171] Block copolymer solution: The content of block copolymer is 2wt%. The preparation process is as follows: after dissolving the block copolymer in an organic solvent, it is filtered with a PTFE filter with an average pore size of 0.45μm.

[0172] Pure water;

[0173] NaPMA solution: concentration 15wt%, solvent is pure water;

[0174] Microfiltration membrane: made of PVDF, with an average pore size of 0.22μm, circular shape, and a diameter of 25mm;

[0175] Good solvent: Toluene;

[0176] Unsuitable solvent: Methanol;

[0177] Mixed solvent: composed of a good solvent and a bad solvent in a volume ratio of 40:60;

[0178] Metal salt: Cobalt nitrate hexahydrate;

[0179] Organic ligand A: 2-methylimidazole;

[0180] The mixed solution consists of a metal salt, organic ligand A, and pure water. The concentration of the metal ion is 0.06 mol / L, and the concentration of organic ligand A in the mixed solution is 0.4 mol / L.

[0181] (2) Preparation of nanoporous block copolymer membranes;

[0182] First, 75 μL of NaPMA solution was dropped onto a glass slide, and then the microfiltration membrane was placed on the surface of the NaPMA solution. After standing for 3 minutes, 450 μL of block copolymer solution was dropped onto the microfiltration membrane. The solution was then coated onto the surface of the microfiltration membrane using a spin coater at a rotation speed of 3000 rpm and a rotation time of 30 seconds to obtain a composite membrane.

[0183] The composite membrane was then immersed in pure water to remove the NaPMA filling, and then treated in a vacuum oven at 33.6 kPa and 110°C for 20 minutes, and then gradually reduced to 30°C at a cooling rate of 1°C per minute.

[0184] Next, the composite membrane is immersed in the mixed solvent for 3 seconds at a temperature of 25°C.

[0185] Finally, the composite membrane was immediately transferred to the undesirable solvent methanol to terminate pore formation. The composite membrane was then removed and naturally dried to obtain a nanoporous block copolymer membrane.

[0186] (3) Preparation of Fenton-like catalytic membranes based on block copolymers;

[0187] The nanoporous block copolymer membrane obtained in step (2) was immersed in 50 mL of mixed solution for reaction at 25 °C for 1 h. The nanoporous block copolymer membrane contains pyridine groups as organic ligands B for metal ions. The metal ions simultaneously form coordination bonds with pyridine groups and organic ligands A, thereby achieving the synthesis of MOF on the surface and inside the pores of the nanoporous block copolymer membrane, and obtaining a MOF-functionalized Fenton-like catalytic membrane. The MOF-functionalized Fenton-like catalytic membrane was removed, rinsed with deionized water, and dried in an oven with a vacuum degree <100 Pa to obtain the block copolymer-based Fenton-like catalytic membrane with an average pore size of 78 nm.

[0188] The aforementioned Fenton-like catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0189] First, potassium persulfate was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 7, resulting in a final concentration of 0.1 g / L, to obtain the dye solution.

[0190] The Fenton-like catalytic membrane prepared in Example 5 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area). 2 In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0191] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the Fenton-like catalytic membrane was then collected. The permeability of the Fenton-like catalytic membrane and the removal rate of Rhodamine B were calculated after testing. The results showed that the permeability of the Fenton-like catalytic membrane was still as high as 2958 L / (m³). 2 Even at ·h·bar), the removal rate of Rhodamine B remained as high as 92.3%.

[0192] Example 6

[0193] A method for preparing a Fenton-like catalytic membrane based on block copolymers, comprising the following specific steps:

[0194] (1) Preparation of raw materials;

[0195] Block copolymer: PS-b-P4VP, P4VP molecular weight is 20 kg / mol, PS-b-P4VP molecular weight is 140 kg / mol;

[0196] Organic solvent: acetone;

[0197] Block copolymer solution: The content of block copolymer is 2.2 wt%. The preparation process is as follows: after dissolving the block copolymer in an organic solvent, it is filtered with a PTFE filter with an average pore size of 0.45 μm.

[0198] Pure water;

[0199] NaPMA solution: concentration 15wt%, solvent is pure water;

[0200] Microfiltration membrane: made of PVDF, with an average pore size of 0.22μm, circular shape, and a diameter of 25mm;

[0201] Good solvent: Toluene;

[0202] Unsuitable solvent: Methanol;

[0203] Mixed solvent: composed of a good solvent and a bad solvent in a volume ratio of 35:65;

[0204] Metal salt: Copper acetate monohydrate;

[0205] Organic ligand A: 2-methylimidazole;

[0206] The mixed solution consists of a metal salt, organic ligand A, and pure water. The concentration of the metal ion is 0.03 mol / L, and the concentration of organic ligand A in the mixed solution is 0.4 mol / L.

[0207] (2) Preparation of nanoporous block copolymer membranes;

[0208] First, 75 μL of NaPMA solution was dropped onto a glass slide, and then the microfiltration membrane was placed on the surface of the NaPMA solution. After standing for 3 minutes, 450 μL of block copolymer solution was dropped onto the microfiltration membrane. The solution was then coated onto the surface of the microfiltration membrane using a spin coater at a rotation speed of 3000 rpm and a rotation time of 30 seconds to obtain a composite membrane.

[0209] The composite membrane was then immersed in pure water to remove the NaPMA filling, and then treated in a vacuum oven at 33.6 kPa and 110°C for 20 minutes, and then gradually reduced to 30°C at a cooling rate of 1°C per minute.

[0210] Next, the composite membrane is immersed in the mixed solvent for 3 seconds at a temperature of 25°C.

[0211] Finally, the composite membrane was immediately transferred to the undesirable solvent methanol to terminate pore formation. The composite membrane was then removed and naturally dried to obtain a nanoporous block copolymer membrane.

[0212] (3) Preparation of Fenton-like catalytic membranes based on block copolymers;

[0213] The nanoporous block copolymer membrane obtained in step (2) was immersed in 50 mL of mixed solution for reaction at 25 °C for 1 h. The nanoporous block copolymer membrane contains pyridine groups as organic ligands B for metal ions. The metal ions simultaneously form coordination bonds with pyridine groups and organic ligands A, thereby achieving the synthesis of MOF on the surface and inside the pores of the nanoporous block copolymer membrane, and obtaining a MOF-functionalized Fenton-like catalytic membrane. The MOF-functionalized Fenton-like catalytic membrane was taken out, rinsed with deionized water, and dried in an oven with a vacuum degree <100 Pa to obtain the block copolymer-based Fenton-like catalytic membrane with an average pore size of 69.9 nm.

[0214] The aforementioned Fenton-like catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0215] First, potassium persulfate was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 7, resulting in a final concentration of 0.1 g / L, to obtain the dye solution.

[0216] The Fenton-like catalytic membrane prepared in Example 6 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area). 2 In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0217] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the Fenton-like catalytic membrane was then collected. The permeability of the Fenton-like catalytic membrane and the removal rate of Rhodamine B were calculated after testing. The results showed that the permeability of the Fenton-like catalytic membrane was still as high as 1860 L / (m³). 2 Even at ·h·bar), the removal rate of Rhodamine B remained as high as 96.3%.

[0218] Example 7

[0219] A method for preparing a Fenton-like catalytic membrane based on block copolymers, comprising the following specific steps:

[0220] (1) Preparation of raw materials;

[0221] Block copolymer: PS-b-P2VP, P2VP molecular weight is 28.6 kg / mol, PS-b-P2VP molecular weight is 100.8 kg / mol;

[0222] Organic solvent: chloroform;

[0223] Block copolymer solution: The content of block copolymer is 2.5 wt%. The preparation process is as follows: after dissolving the block copolymer in an organic solvent, it is filtered with a PTFE filter with an average pore size of 0.45 μm.

[0224] Pure water;

[0225] NaPMA solution: concentration 15wt%, solvent is pure water;

[0226] Microfiltration membrane: made of PVDF, with an average pore size of 0.22μm, circular shape, and a diameter of 25mm;

[0227] Good solvent: chloroform;

[0228] Unsuitable solvent: Methanol;

[0229] Mixed solvent: composed of a good solvent and a poor solvent in a volume ratio of 20:80;

[0230] Metal salt: Ferric chloride hexahydrate;

[0231] Organic ligand A: 1,3,5-Benzotricarboxylic acid;

[0232] Mixed solution: composed of metal salt, organic ligand A and pure water, with a metal ion concentration of 0.01 mol / L and an organic ligand A concentration of 0.01 mol / L in the mixed solution;

[0233] (2) Preparation of nanoporous block copolymer membranes;

[0234] First, 75 μL of NaPMA solution was dropped onto a glass slide, and then the microfiltration membrane was placed on the surface of the NaPMA solution. After standing for 3 minutes, 450 μL of block copolymer solution was dropped onto the microfiltration membrane. The solution was then coated onto the surface of the microfiltration membrane using a spin coater at a rotation speed of 3000 rpm and a rotation time of 30 seconds to obtain a composite membrane.

[0235] The composite membrane was then immersed in pure water to remove the NaPMA filling, and then treated in a vacuum oven at 33.6 kPa and 110°C for 20 minutes, and then gradually reduced to 30°C at a cooling rate of 1°C per minute.

[0236] Next, the composite membrane is immersed in the mixed solvent for 5 seconds at a temperature of 25°C.

[0237] Finally, the composite membrane was immediately transferred to the undesirable solvent methanol to terminate pore formation. The composite membrane was then removed and naturally dried to obtain a nanoporous block copolymer membrane.

[0238] (3) Preparation of Fenton-like catalytic membranes based on block copolymers;

[0239] The nanoporous block copolymer membrane obtained in step (2) was immersed in 50 mL of mixed solution for reaction at 25 °C for 1 h. The nanoporous block copolymer membrane contains pyridine groups as organic ligands B for metal ions. The metal ions simultaneously form coordination bonds with pyridine groups and organic ligands A, thereby achieving the synthesis of MOF on the surface and inside the pores of the nanoporous block copolymer membrane, and obtaining a MOF-functionalized Fenton-like catalytic membrane. The MOF-functionalized Fenton-like catalytic membrane was removed, rinsed with deionized water, and dried in an oven with a vacuum degree <100 Pa to obtain a block copolymer-based Fenton-like catalytic membrane with an average pore size of 20 nm.

[0240] The aforementioned Fenton-like catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0241] First, hydrogen peroxide was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 3.5, resulting in a final concentration of 0.15 mol / L, to obtain the dye solution.

[0242] The Fenton-like catalytic membrane prepared in Example 7 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area). 2 In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0243] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the Fenton-like catalytic membrane was then collected. The permeability of the Fenton-like catalytic membrane and the removal rate of Rhodamine B were calculated after testing. The results showed that the permeability of the Fenton-like catalytic membrane was still as high as 756 L / (m³). 2 Even at ·h·bar), the removal rate of Rhodamine B remained as high as 96%.

[0244] Example 8

[0245] A method for preparing a Fenton-like catalytic membrane based on block copolymers, comprising the following specific steps:

[0246] (1) Preparation of raw materials;

[0247] Block copolymer: PS-b-PMMA, CAS No. 25034-86-0, Polymer Source, Canada, brand name Polymer Source;

[0248] Block copolymer: PS-b-PMMA, PMMA molecular weight is 35 kg / mol, PS-b-PMMA molecular weight is 117 kg / mol;

[0249] Organic solvent: chloroform;

[0250] Block copolymer solution: The content of block copolymer is 2wt%. The preparation process is as follows: after dissolving the block copolymer in an organic solvent, it is filtered with a PTFE filter with an average pore size of 0.45μm.

[0251] Pure water;

[0252] NaPMA solution: concentration 15wt%, solvent is pure water;

[0253] Microfiltration membrane: made of PVDF, with an average pore size of 0.22μm, circular shape, and a diameter of 25mm;

[0254] Good solvent: Toluene;

[0255] Unsuitable solvent: Ethanol;

[0256] Mixed solvent: composed of a good solvent and a poor solvent in a volume ratio of 30:70;

[0257] Metal salt: Cobalt nitrate hexahydrate;

[0258] Organic ligand A: 2-methylimidazole;

[0259] Mixed solution: composed of metal salt, organic ligand A and pure water, with a metal ion concentration of 0.01 mol / L and an organic ligand A concentration of 0.01 mol / L in the mixed solution;

[0260] (2) Preparation of nanoporous block copolymer membranes;

[0261] First, 75 μL of NaPMA solution was dropped onto a glass slide, and then the microfiltration membrane was placed on the surface of the NaPMA solution. After standing for 3 minutes, 450 μL of block copolymer solution was dropped onto the microfiltration membrane. The solution was then coated onto the surface of the microfiltration membrane using a spin coater at a rotation speed of 3000 rpm and a rotation time of 30 seconds to obtain a composite membrane.

[0262] The composite membrane was then immersed in pure water to remove the NaPMA filling, and then treated in a vacuum oven at 33.6 kPa and 110°C for 20 minutes, and then gradually reduced to 30°C at a cooling rate of 1°C per minute.

[0263] Next, the composite membrane is immersed in the mixed solvent for 5 seconds at a temperature of 25°C.

[0264] Finally, the composite membrane was immediately transferred to the undesirable solvent methanol to terminate pore formation. The composite membrane was then removed and naturally dried to obtain a nanoporous block copolymer membrane.

[0265] (3) Preparation of Fenton-like catalytic membranes based on block copolymers;

[0266] The nanoporous block copolymer membrane obtained in step (2) was immersed in 50 mL of mixed solution for reaction at 25 °C for 1 h. The nanoporous block copolymer membrane contains ester groups (-COO-) as organic ligands B for metal ions. The metal ions simultaneously form coordination bonds with the ester groups and organic ligands A, thereby achieving the synthesis of MOF on the surface and inside the pores of the nanoporous block copolymer membrane, and obtaining a MOF-functionalized Fenton-like catalytic membrane. The MOF-functionalized Fenton-like catalytic membrane was removed, rinsed with deionized water, and dried in an oven with a vacuum degree <100 Pa to obtain the block copolymer-based Fenton-like catalytic membrane with an average pore size of 20.1 nm.

[0267] The aforementioned Fenton-like catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0268] First, potassium persulfate was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 7, resulting in a final concentration of 0.1 g / L, to obtain the dye solution.

[0269] The Fenton-like catalytic membrane prepared in Example 8 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area). 2 In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0270] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the Fenton-like catalytic membrane was then collected. The permeability of the Fenton-like catalytic membrane and the removal rate of Rhodamine B were calculated after testing. The results showed that the permeability of the Fenton-like catalytic membrane was still as high as 736 L / (m³). 2 Even at ·h·bar), the removal rate of Rhodamine B remained as high as 96.6%.

[0271] Example 9

[0272] A method for preparing a Fenton-like catalytic membrane based on block copolymers, comprising the following specific steps:

[0273] (1) Preparation of raw materials;

[0274] Block copolymer: PSf-b-PEG, PEG molecular weight is 37 kg / mol, PSf-b-PEG molecular weight is 135 kg / mol;

[0275] Organic solvent: chloroform;

[0276] Block copolymer solution: The content of block copolymer is 2wt%. The preparation process is as follows: after dissolving the block copolymer in an organic solvent, it is filtered with a PTFE filter with an average pore size of 0.45μm.

[0277] Pure water;

[0278] NaPMA solution: concentration 15wt%, solvent is pure water;

[0279] Microfiltration membrane: made of PTFE, with an average pore size of 0.22μm, circular shape, and a diameter of 25mm;

[0280] Good solvent: Toluene;

[0281] Unsuitable solvent: Methanol;

[0282] Mixed solvent: composed of a good solvent and a poor solvent in a volume ratio of 30:70;

[0283] Metal salt: Cobalt nitrate hexahydrate;

[0284] Organic ligand A: 2-methylimidazole;

[0285] The mixed solution consists of a metal salt, organic ligand A, and pure water. The concentration of the metal ion is 0.06 mol / L, and the concentration of organic ligand A in the mixed solution is 0.2 mol / L.

[0286] (2) Preparation of nanoporous block copolymer membranes;

[0287] First, 75 μL of NaPMA solution was dropped onto a glass slide, and then the microfiltration membrane was placed on the surface of the NaPMA solution. After standing for 3 minutes, 450 μL of block copolymer solution was dropped onto the microfiltration membrane. The solution was then coated onto the surface of the microfiltration membrane using a spin coater at a rotation speed of 3000 rpm and a rotation time of 30 seconds to obtain a composite membrane.

[0288] The composite membrane was then immersed in pure water to remove the NaPMA filling, and then treated in a vacuum oven at 33.6 kPa and 110°C for 20 minutes, and then gradually reduced to 30°C at a cooling rate of 1°C per minute.

[0289] Next, the composite membrane is immersed in the mixed solvent for 1 second at a temperature of 25°C.

[0290] Finally, the composite membrane was immediately transferred to the undesirable solvent methanol to terminate pore formation. The composite membrane was then removed and naturally dried to obtain a nanoporous block copolymer membrane.

[0291] (3) Preparation of Fenton-like catalytic membranes based on block copolymers;

[0292] The nanoporous block copolymer membrane obtained in step (2) was immersed in 50 mL of mixed solution for reaction at 25 °C for 1 h. The nanoporous block copolymer membrane contains siloxy groups as organic ligands B for metal ions. The metal ions simultaneously form coordination bonds with siloxy groups and organic ligands A, thereby achieving the synthesis of MOF on the surface and inside the pores of the nanoporous block copolymer membrane, and obtaining a MOF-functionalized Fenton-like catalytic membrane. The MOF-functionalized Fenton-like catalytic membrane was removed, rinsed with deionized water, and dried in an oven with a vacuum degree <100 Pa to obtain the block copolymer-based Fenton-like catalytic membrane with an average pore size of 77.8 nm.

[0293] The aforementioned Fenton-like catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0294] First, potassium persulfate was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 7, resulting in a final concentration of 0.1 g / L, to obtain the dye solution.

[0295] The Fenton-like catalytic membrane prepared in Example 9 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area). 2 In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0296] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the Fenton-like catalytic membrane was then collected. The permeability of the Fenton-like catalytic membrane and the removal rate of Rhodamine B were calculated after testing. The results showed that the permeability of the Fenton-like catalytic membrane was still as high as 2593 L / (m³). 2 Even at ·h·bar), the removal rate of Rhodamine B remained as high as 92.9%.

[0297] Example 10

[0298] A method for preparing a Fenton-like catalytic membrane based on block copolymers, comprising the following specific steps:

[0299] (1) Preparation of raw materials;

[0300] Block copolymer: PS-b-P2VP, P2VP molecular weight is 28.6 kg / mol, PS-b-P2VP molecular weight is 100.8 kg / mol;

[0301] Organic solvent: chloroform;

[0302] Block copolymer solution: The content of block copolymer is 2wt%. The preparation process is as follows: after dissolving the block copolymer in an organic solvent, it is filtered with a PTFE filter with an average pore size of 0.45μm.

[0303] Pure water;

[0304] NaPMA solution: concentration 15wt%, solvent is pure water;

[0305] Microfiltration membrane: made of PVDF, with an average pore size of 0.22μm, circular shape, and a diameter of 25mm;

[0306] Good solvent: Toluene;

[0307] Unsuitable solvent: Methanol;

[0308] Mixed solvent: composed of a good solvent and a poor solvent in a volume ratio of 30:70;

[0309] Metal salt: Ferric chloride hexahydrate;

[0310] Organic ligand A: 2-aminoterephthalic acid;

[0311] Mixed solution: composed of metal salt, organic ligand A and pure water, with a metal ion concentration of 0.01 mol / L and an organic ligand A concentration of 0.01 mol / L in the mixed solution;

[0312] (2) Preparation of nanoporous block copolymer membranes;

[0313] First, 75 μL of NaPMA solution was dropped onto a glass slide, and then the microfiltration membrane was placed on the surface of the NaPMA solution. After standing for 3 minutes, 450 μL of block copolymer solution was dropped onto the microfiltration membrane. The solution was then coated onto the surface of the microfiltration membrane using a spin coater at a rotation speed of 3000 rpm and a rotation time of 30 seconds to obtain a composite membrane.

[0314] The composite membrane was then immersed in pure water to remove the NaPMA filling, and then treated in a vacuum oven at 33.6 kPa and 110°C for 20 minutes, and then gradually reduced to 30°C at a cooling rate of 1°C per minute.

[0315] Next, the composite membrane is immersed in the mixed solvent for 3 seconds at a temperature of 25°C.

[0316] Finally, the composite membrane was immediately transferred to the undesirable solvent methanol to terminate pore formation. The composite membrane was then removed and naturally dried to obtain a nanoporous block copolymer membrane.

[0317] (3) Preparation of Fenton-like catalytic membranes based on block copolymers;

[0318] The nanoporous block copolymer membrane obtained in step (2) was immersed in 50 mL of mixed solution for reaction at 25 °C for 1 h. The pyridine group contained in the nanoporous block copolymer membrane served as organic ligand B for the metal ions. The metal ions formed coordination bonds with both the pyridine group and the organic ligand A, thereby achieving the synthesis of MOF on the surface and inside the pores of the nanoporous block copolymer membrane, and obtaining a MOF-functionalized Fenton-like catalytic membrane. The MOF-functionalized Fenton-like catalytic membrane was then removed, rinsed with deionized water, and dried in an oven with a vacuum degree <100 Pa to obtain the block copolymer-based Fenton-like catalytic membrane with an average pore size of 25 nm.

[0319] The aforementioned Fenton-like catalytic membrane can be used to remove dyes from wastewater. To study its removal efficiency, the following experiments were conducted:

[0320] First, hydrogen peroxide was added to an aqueous solution of Rhodamine B with a concentration of 10 mg / L and a pH of 3.5, resulting in a final concentration of 0.15 mol / L, to obtain the dye solution.

[0321] The Fenton-like catalytic membrane prepared in Example 10 was then installed in a stainless steel ultrafiltration cup (500 mL volume, 1.76 cm² effective membrane area). 2 In this process, deionized water is added to a stainless steel ultrafiltration cup and filtered for 0.5 hours at 0.1 bar and 25°C to obtain a stable water flow.

[0322] Finally, the dye solution was added to a stainless steel ultrafiltration cup and filtered for 2 hours at 0.1 bar and 25°C. The dye solution permeating from the Fenton-like catalytic membrane was then collected. The permeability of the Fenton-like catalytic membrane and the removal rate of Rhodamine B were calculated after testing. The results showed that the permeability of the Fenton-like catalytic membrane was still as high as 936 L / (m³). 2 Even at ·h·bar), the removal rate of Rhodamine B remained as high as 90.1%.

[0323] It will be understood by those skilled in the art that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a Fenton-like catalytic membrane based on block copolymers, characterized in that, The nanoporous block copolymer membrane is immersed in a mixed solution containing metal ions and organic ligand A for reaction. The nanoporous block copolymer membrane contains organic ligand B. The metal ions simultaneously form coordination bonds with organic ligand A and organic ligand B, thereby achieving the synthesis of MOF on the surface and inside the pores of the nanoporous block copolymer membrane, thus obtaining a Fenton-like catalytic membrane based on block copolymer. The metal ion is at least one of cobalt ion, iron ion and copper ion; the organic ligand A is at least one of 2-methylimidazolium, 1,3,5-benzenetricarboxylic acid and 2-aminoterephthalic acid; the organic ligand B is pyridyl, amino, carboxyl, ester, siloxy or alkoxy.

2. The method for preparing a Fenton-like catalytic membrane based on a block copolymer according to claim 1, characterized in that, The reaction temperature was 25℃ and the reaction time was 1 hour.

3. The method for preparing a Fenton-like catalytic membrane based on a block copolymer according to claim 1, characterized in that, The concentration of metal ions in the mixed solution is 0.01-0.06 mol / L, and the concentration of organic ligand A in the mixed solution is 0.01-0.4 mol / L.

4. The method for preparing a Fenton-like catalytic membrane based on a block copolymer according to claim 1, characterized in that, Nanoporous block copolymer membranes are obtained through the following steps: (1) Add the block copolymer solution to the microfiltration membrane, rotate the microfiltration membrane with a spin coater to uniformly coat the surface of the microfiltration membrane with the block copolymer solution, and dry to obtain a composite membrane; (2) Immerse the composite membrane in a mixed solvent containing a good solvent and a bad solvent, and then transfer it to the bad solvent to obtain a nanoporous block copolymer membrane.

5. The method for preparing a Fenton-like catalytic membrane based on a block copolymer according to claim 4, characterized in that, In step (1), the block copolymer in the block copolymer solution is composed of block a and block b, wherein block a is polystyrene, polysulfone, polyethylene or polycyclohexene carbonate, and block b is poly(2-vinylpyridine), polyethylene oxide, poly(4-vinylpyridine), polymethyl methacrylate, polymethacrylic acid, N,N-dimethylaminoethyl methacrylate, polyethylene glycol or polylactic acid; wherein the volume of block b accounts for 1-60% of the total volume of block a and block b; the molecular weight of the block copolymer is 5-800 kg / mol.

6. The method for preparing a Fenton-like catalytic membrane based on a block copolymer according to claim 5, characterized in that, In step (1), the block copolymer solution is obtained by dissolving at least one block copolymer in an organic solvent, the organic solvent being at least one of acetone and chloroform, and the block copolymer content in the block copolymer solution is 1-5 wt%.

7. The method for preparing a Fenton-like catalytic membrane based on a block copolymer according to claim 4, characterized in that, In step (2), the good solvent is at least one of acetone, chloroform, tetrahydrofuran, toluene, 1,2-dichlorobenzene and cyclohexane, and the bad solvent is at least one of methanol, ethanol, 2-propanol, acetic acid and n-hexadecane. The volume ratio of the good solvent to the bad solvent is 1 / 9-5 / 5, the soaking time is 1-60s, and the soaking temperature is 25℃.

8. A Fenton-like catalytic membrane based on block copolymers, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.

9. The application of a Fenton-like catalytic membrane based on block copolymers as described in claim 8, characterized in that, Used for removing dyes from wastewater; after a period of use, the permeability of the block copolymer-based Fenton-like catalytic membrane is 736-3070 L / (m²). 2 The dye removal rate is 89.6-100% (·h·bar), and the dye is filtered for 2 hours at 0.1 bar and 25°C after a period of use.

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