Ag-Cu particle loaded polyamide nanofiltration composite catalytic membrane as well as preparation method and application thereof
By preparing a polyamide nanofiltration composite membrane on a PVDF membrane and loading Ag-Cu particles, the problems of poor retention of 4-nitrophenol and difficulty in catalyst recovery of traditional nanofiltration membranes were solved. This achieved efficient removal of 4-nitrophenol and salts while reducing energy consumption and improving catalyst recovery rate and stability.
Patent Information
- Application Number
- CN202511069260.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-31
- Publication Date
- 2026-02-24
AI Technical Summary
In the existing technology, traditional nanofiltration membranes have poor retention effect on 4-nitrophenol, and the catalyst is not easy to recover and reuse, resulting in high energy consumption and low reusability in the removal of 4-nitrophenol.
A polyamide nanofiltration composite membrane was prepared on a PVDF membrane, and Ag-Cu particles were loaded through a photochemical reduction reaction to form an Ag-Cu/polyamide nanofiltration composite catalytic membrane. Combined with a displacement reaction, the membrane was used to catalyze the reduction of 4-nitrophenol while maintaining the retention effect of salts.
While achieving efficient removal of 4-nitrophenol, it improved the catalyst recovery rate and reusability, reduced separation energy consumption, and maintained high salt rejection rate and catalytic stability.
Smart Images
Figure CN121550847A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of environmental protection technology, and in particular to a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles and its preparation method. Background Technology
[0002] 4-Nitrophenol (4-NP) is a common nitroaromatic hydrocarbon pollutant in industrial wastewater. Due to its poor biodegradability, stable physicochemical properties, high toxicity, and easy bioaccumulation, 4-nitrophenol accumulates continuously in the surrounding environment, seriously endangering human living environment and health. Currently, a widely used and effective method for removing 4-nitrophenol is sodium borohydride (NaBH4) as a reducing agent under the action of a catalyst. However, this method suffers from problems such as difficulty in catalyst recovery, low reuse rate, and high energy consumption. Simultaneously, industrial wastewater also contains a large amount of salt, and the reduction process using sodium borohydride introduces salt pollution. These salts typically have a molecular weight of less than 1000 Da. To remove salts from wastewater, a separation membrane with a small pore size is needed, such as a nanofiltration membrane with a high pollutant rejection rate. However, traditional nanofiltration membranes are not effective at retaining highly toxic nitrophenol pollutants. The effective way to remove 4-nitrophenol is to use a high-performance catalyst for degradation, but traditional nanofiltration membranes do not possess catalytic reduction capabilities. Therefore, there is a need for a nanofiltration membrane that has catalytic reduction function for 4-nitrophenol (4-NP), which retains its retention function while also having catalytic performance, thus solving the problems of difficult catalyst recovery and low reusability of traditional removal methods. Summary of the Invention
[0003] The purpose of this invention is to provide a polyamide nanofiltration composite catalytic membrane supported on Ag-Cu particles and its preparation method. This invention retains its retention function while also possessing catalytic performance, achieving both efficient removal of 4-nitrophenol (4-NP) and retention of salts. It solves the problems of difficult catalyst recovery and low reusability in traditional removal methods, resulting in low separation energy consumption, high separation efficiency, easy recovery, and reusability.
[0004] The technical solution of this invention is as follows: A method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, using a PVDF membrane as a substrate, a polyamide thin layer is prepared on the PVDF membrane to obtain a polyamide nanofiltration composite membrane. Cu nanoparticles are then loaded onto the polyamide nanofiltration composite membrane via a photochemical reduction reaction, followed by a displacement reaction with silver nitrate solution to obtain a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, i.e., an Ag-Cu / polyamide nanofiltration composite catalytic membrane. The Ag-Cu loading is 0.4-0.9 mg / cm³. 2The percentage of Ag in the Ag-Cu is 81.16%-86.96%. The Ag-Cu loading and mass ratio enable the Ag-Cu / polyamide nanofiltration composite catalytic membrane to have a significant catalytic reduction effect on the removal of 4-nitrophenol, while also having a high salt rejection rate.
[0005] The aforementioned method for preparing the polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles includes the following steps: A. Using a PVDF membrane as the substrate, place it in a membrane-forming frame, pour the aqueous PIP solution into the membrane-forming frame, and after fully wetting it, pour out the remaining PIP solution, air dry it naturally for 3-10 minutes, remove the residual solution, pour in the oil phase TMC solution, and after full contact, take out the PVDF membrane and place it in an oven at 40-80℃. After 10-20 minutes, take it out to obtain a polyamide nanofiltration composite membrane. B. Take a polyamide nanofiltration composite membrane with the filter side facing up and place it on the surface of an ethanol solution containing Cu(NO3)2 / benzophenone. Make sure the solution fully wets the polyamide nanofiltration composite membrane and place it in a closed reaction container to obtain a closed reaction system. C. Place the closed reaction system under ultraviolet light for 30-120 min. The photoinitiator benzophenone absorbs ultraviolet light and reacts with the co-initiator ethanol to generate active free radicals that reduce Cu ions in the solution to Cu nanoparticles, which are then loaded onto the surface and pores of the PVDF membrane. After the irradiation is complete, the membrane is removed and rinsed to obtain a Cu / polyamide nanofiltration composite membrane. D. The Cu / polyamide nanofiltration composite membrane is placed in an ethanol solution of silver nitrate to undergo a complete displacement reaction, resulting in an Ag-Cu / polyamide nanofiltration composite catalytic membrane.
[0006] In the aforementioned method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, in step A, the concentration of the PIP solution is 0.05%-1%, and the concentration of the TMC is 0.05%-0.4%.
[0007] In the aforementioned method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, in step A, the concentration of the PIP solution is 0.1%, and the concentration of the TMC is 0.1%.
[0008] In the aforementioned method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, in step B, the concentration of Cu(NO3)2 is 0.025-0.11 mol / L, and the concentration of benzophenone is 0.05-0.22 mol / L.
[0009] In the aforementioned method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, in step B, the concentration of Cu(NO3)2 is 0.08 mol / L and the concentration of benzophenone is 0.16 mol / L.
[0010] In the aforementioned method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, in step B, the concentration ratio of Cu(NO3)2 to benzophenone is 1:2. This concentration ratio can increase the loading of copper nanoparticles.
[0011] In the aforementioned method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, in step B, the closed reaction system is evacuated to 20 kPa.
[0012] In the aforementioned method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, in step C, the power of the ultraviolet light source is 50W, and the wavelength of the ultraviolet light is 365nm.
[0013] In the aforementioned method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, in step D, the concentration of the silver nitrate ethanol solution is 0.02-0.05 mL / L.
[0014] A polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, wherein the polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles is prepared by the aforementioned method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles.
[0015] Application of Ag-Cu particle-loaded polyamide nanofiltration composite catalytic membrane in the catalytic reduction of nitrophenol compounds.
[0016] In the aforementioned applications, the polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles was used for the catalytic reduction of wastewater containing 4-nitrophenol.
[0017] Compared with existing technologies, this invention prepares a polyamide thin layer on a PVDF substrate to obtain a polyamide nanofiltration composite membrane, which can retain small salt molecules. Then, Ag-Cu nanoparticles are loaded onto the PVDF substrate through a photochemical reduction followed by displacement. In this invention, copper ions are first photochemically reduced and deposited onto the PVDF substrate, resulting in a dense and uniform loading of copper nanoparticles. This significantly improves the loading of silver nanoparticles after the displacement reaction and provides better adhesion morphology, thus giving the Ag-Cu / polyamide nanofiltration composite catalytic membrane better catalytic effect and stability. Regarding the catalytic reduction of 4-nitrophenol, loading only Cu particles resulted in poor catalytic effect, with a removal rate of around 35% (the yellow highlighted part in Experiment 4 below shows that loading an equal amount of Cu has a certain catalytic effect); loading only Ag particles resulted in poor catalytic effect, with a removal rate of around 43%; while loading Ag-Cu nanoparticles produced a synergistic effect, with a significant catalytic effect and a removal rate of over 98%. Simultaneously, loading Ag-Cu nanoparticles also increases the loading of silver nanoparticles. This invention retains its retention function while also possessing catalytic performance, achieving both efficient removal of 4-nitrophenol (4-NP) and retention of its salts. It solves the problems of difficult catalyst recovery and low reusability in traditional removal methods, resulting in low separation energy consumption, high separation efficiency, easy recovery, and reusability. Attached Figure Description
[0018] Figure 1 These are surface SEM images of the PVDF ultrafiltration membrane, polyamide nanofiltration composite membrane, and Ag-Cu / polyamide nanofiltration composite catalytic membrane according to embodiments of the present invention. Figure 2 These are cross-sectional SEM images of the PVDF ultrafiltration membrane, polyamide nanofiltration composite membrane, and Ag-Cu / polyamide nanofiltration composite catalytic membrane according to embodiments of the present invention. Figure 3 This is an EDS-Mapping image of the Ag-Cu / polyamide nanofiltration composite catalytic membrane surface in an embodiment of the present invention; Figure 4 This is an EDS-Mapping diagram of the cross-section of the Ag-Cu / polyamide nanofiltration composite catalytic membrane in an embodiment of the present invention; Figure 5 The attached diagram shows a catalytic reaction apparatus for 4-nitrophenol, labeled as follows: 1-outlet flow meter, 2-pressure control valve, 3-pressure gauge, 4-pressure relief valve, 5-inlet flow meter, 6-inlet tank, 7-pump, 8-membrane device, 9-permeate. Detailed Implementation
[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.
[0020] Example 1. Preparation of PVDF ultrafiltration membrane First, after drying the PVDF in a vacuum drying oven, add the PVDF and PEG400 sequentially to the casting solution bottle according to the formulation in Table 1, followed by CaCl2 and DMAC. After preparing the casting solution, immediately cap the bottle and thoroughly mix it using ultrasound, then place it in an 80℃ oven. Wait until the casting solution is uniformly transparent and completely mixed before coating the PVDF membrane. Using PET material as a substrate, fabricate the membrane using a membrane coating machine. Soak the prepared PVDF ultrafiltration membrane thoroughly in tap water to remove excess solvent.
[0021] Table 1 reagents Proportion(%) PVDF 16 <![CDATA[CaCl2]]> 2 PEG400 5 DMAc 77 Example 2. Preparation of Ag-Cu / polyamide nanofiltration composite catalytic membrane Using the PVDF flat sheet membrane prepared in Example 1 as the substrate, a membrane forming frame was placed on it. A 0.1% aqueous PIP solution was poured into the frame and allowed to fully impregnate the membrane. The PIP solution was then poured out, and the membrane was allowed to air dry for 5 minutes. Any residual solution was blotted dry with filter paper. Subsequently, a 0.1% oil TMC solution was poured in and allowed to fully contact the membrane before removing it. The membrane was then placed in an oven at 60°C and dried for 15 minutes to obtain a polyamide nanofiltration composite membrane.
[0022] A polyamide nanofiltration composite membrane sample measuring 8cm × 6cm was prepared with the filter side facing upwards and placed on the surface of an ethanol solution containing Cu(NO3)2 / benzophenone (the concentration of Cu(NO3)2 was 0.08 mol / L and the concentration of benzophenone was 0.16 mol / L). A solution of 0.05 mol / L silver nitrate solution was used to fully wet the polyamide nanofiltration composite membrane. The membrane was placed in a sealed reaction vessel, evacuated to 20 kPa, and irradiated under ultraviolet light (50W 365nm UV lamp) for 1.5 hours. Benzophenone and ethanol underwent a bimolecular reaction to generate active free radicals, reducing copper ions to copper nanoparticles, which were then loaded onto the surface and pores of the polyamide nanofiltration composite membrane. The irradiated polyamide nanofiltration composite membrane loaded with copper nanoparticles was then repeatedly washed with ethanol and deionized water to remove surface solution, yielding a Cu / polyamide nanofiltration composite membrane. Finally, a thorough displacement reaction was carried out with 0.05 mol / L silver nitrate solution for 5 minutes to obtain an Ag-Cu / polyamide nanofiltration composite catalytic membrane. After thorough cleaning, the membrane was stored in deionized water. The Ag-Cu loading in the Ag-Cu / polyamide nanofiltration composite catalytic membrane was 0.9 mg / cm³. 2 The percentage of Ag in the Ag-Cu is 81.16%.
[0023] Example 3. Application of Ag-Cu particle-loaded polyamide nanofiltration composite catalytic membrane in the catalytic reduction of nitrophenol compounds. The polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles prepared in the examples was used for the catalytic reduction treatment of wastewater containing 4-nitrophenol.
[0024] Example 1. Morphology analysis of Ag-Cu / polyamide nanofiltration composite catalytic membrane The PVDF ultrafiltration membrane, polyamide nanofiltration composite membrane, and Ag-Cu / polyamide nanofiltration composite catalytic membrane were scanned by SEM. The results are shown in [Figure number missing]. Figure 1 and Figure 2 (where a and d are PVDF ultrafiltration membranes, b and c are polyamide nanofiltration composite membranes, and c and f are Ag-Cu / polyamide nanofiltration composite catalytic membranes). from Figure 1 It can be seen that the PVDF membrane surface has uniformly sized pores. After the introduction of a polyamide separation layer through interfacial polymerization, the pores of the PVDF ultrafiltration membrane are covered by the ultrathin separation layer, and small, nodular crystals can be seen under high magnification. Nanoparticles are successfully loaded onto the surface of the Ag-Cu / polyamide nanofiltration composite catalytic membrane. Figure 2 It is evident that the Ag-Cu / polyamide nanofiltration composite catalytic membrane contains clearly visible nanoparticle-loaded material within its cross-sectional pores, and the distribution is relatively uniform. From... Figure 1 and Figure 2 It can be seen that the pore structure and size of the three membranes remained unchanged, and the Ag-Cu / polyamide nanofiltration composite catalytic membrane contained a loading material. This indicates that the interfacial polymerization reaction and photochemical reduction and displacement reaction of the polyamide layer introduced into the PVDF ultrafiltration membrane did not change the fine structure of the membrane, thus maintaining the basic performance of the composite membrane.
[0025] EDS-Mapping analysis of the Ag-Cu / polyamide nanofiltration composite catalytic membrane was performed, and the results are shown in the figure. Figure 3 and Figure 4 As shown in the figure, the surface and cross-section of the Ag-Cu / polyamide nanofiltration composite catalytic membrane are both loaded with Ag-Cu nanoparticles. On the surface of the Ag-Cu / polyamide nanofiltration composite catalytic membrane, the mass percentages of carbon, fluorine, oxygen, nitrogen, silver, and copper are 48.6%, 31.5%, 4.1%, 2.0%, 12.0%, and 1.8%, respectively; while in the cross-section, the mass percentages are 37.3%, 42.3%, 4.8%, 1.9%, 11.2%, and 2.6%, respectively. The presence of nitrogen indicates the successful introduction of the polyamide layer, and Ag-Cu nanoparticles are successfully loaded on both the surface and cross-section, but the mass percentage of copper is higher in the cross-section. Thermogravimetric analysis shows that the total content of Ag-Cu nanoparticles in the Ag-Cu / polyamide nanofiltration composite catalytic membrane is approximately 6.6%.
[0026] Experimental Example 2. Chemical Composition Analysis of Ag-Cu / Polyamide Nanofiltration Composite Catalytic Membrane ATR-FTIR analysis was performed on the PVDF ultrafiltration membrane, polyamide nanofiltration composite membrane, and Ag-Cu / polyamide nanofiltration composite catalytic membrane in the examples. The scanning accuracy was set to 2 cm during the test. -1 The scan count was 64 times. It was observed that all three membranes showed characteristic peaks indicating a PVDF ultrafiltration membrane substrate, while the polyamide nanofiltration composite membrane and the Ag-Cu / polyamide nanofiltration composite catalytic membrane showed characteristic peaks of the polyamide layer, indicating successful introduction of the polyamide layer. A comparison of the full spectra of the polyamide nanofiltration composite membrane and the Ag-Cu / polyamide nanofiltration composite catalytic membrane clearly showed signals of Cu 2p and Ag 3d, indicating successful loading of Ag-Cu nanoparticles. The analysis also showed that by combining photochemical reduction and displacement methods, Ag-Cu nanoparticles were successfully loaded onto the polyamide nanofiltration composite membrane without altering its chemical composition.
[0027] X-ray diffraction (XRD) was used to test the PVDF ultrafiltration membrane and the Ag-Cu / polyamide nanofiltration composite catalytic membrane (samples were tested in the range of 0-85°). The results showed that, compared to the PVDF ultrafiltration membrane, the Ag-Cu / polyamide nanofiltration composite catalytic membrane exhibited four diffraction peaks at 2θ: 38.1°, 44.3°, 64.5°, and 77.4°, corresponding to (111), (200), (220), and (311) face-centered cubic crystalline silver (JCPDS 36-1451), respectively, supporting the presence of silver nanoparticles. The diffraction peak at 2θ at 43.3° was (111) FCC crystalline copper, supporting the presence of copper nanoparticles.
[0028] Experimental Example 3. Basic Performance Testing of Ag-Cu / Polyamide Nanofiltration Composite Catalytic Membrane Pure water flux test: After rinsing the Ag-Cu / polyamide nanofiltration composite catalytic membrane sample with pure water, the flux was tested in a triple high-pressure flat-panel membrane pilot-scale apparatus. To ensure the stability of the composite membrane's performance, the sample was pre-pressurized at 0.1 MPa (ultrafiltration) and 0.6 MPa (nanofiltration) for 15 min before each test to achieve flux stability. At 25℃ and 0.6 MPa, the pure water flux of the Ag-Cu / polyamide nanofiltration composite catalytic membrane was measured to be 96.16 L·m⁻¹. -2 ·h -1 .
[0029] Determination of retention capacity: The Ag-Cu / polyamide nanofiltration composite catalytic membrane in the example was first placed in a triple high-pressure flat-panel membrane pilot-scale device for pre-pressure for 10-15 minutes to achieve flux stability. Under the conditions of 25℃ and 0.6MPa, the retention rate of the Ag-Cu / polyamide nanofiltration composite catalytic membrane for divalent salts such as sodium sulfate was measured to be 95.46%.
[0030] Experimental Example 4. Catalytic Performance Testing of Ag-Cu / Polyamide Nanofiltration Composite Catalytic Membrane In the presence of NaBH4, a catalytic reaction can reduce 4-NP to 4-AP. This experimental example will verify the catalytic performance of the Ag-Cu / polyamide nanofiltration composite catalytic membrane by observing the catalytic conversion of 4-NP to 4-AP.
[0031] A 4-nitrophenol catalytic reaction apparatus (such as...) Figure 5 (As shown) To determine the catalytic performance of the Ag-Cu / polyamide nanofiltration composite catalytic membrane, the Ag-Cu / polyamide nanofiltration composite catalytic membrane prepared in Example 2 was placed in membrane device 8. 4-Nitrophenol solution was pumped into membrane device 8 through pump 7, and the filtrate was collected every 15 minutes to determine the removal effect of 4-nitrophenol.
[0032] In this experimental example, the NaBH4 concentration was 0.906 g·L⁻¹. -1 The flux is 80-110 L·m −2 ·h −1 Treating 10 mg·L under the following conditions -1 The total reaction time for the p-nitrophenol solution was 1.5 hours, and the removal rate reached over 98.5%.
[0033] Under the same conditions, the removal rate of p-nitrophenol solution treated with the Ag / polyamide nanofiltration composite catalytic membrane with the same loading was only 43.65%. However, the removal rate of p-nitrophenol solution treated with the Cu / polyamide nanofiltration composite catalytic membrane with the same loading was 35.00%. This demonstrates that the silver and copper nanoparticles deposited in the Ag-Cu / polyamide nanofiltration composite catalytic membrane have a synergistic effect.
[0034] At 2g·L -1 In the presence of Na₂SO₄, eight consecutive filtration cycles were tested. Because NaBH₄ undergoes hydrolysis in water and is consumed, to ensure a constant flow, the feed solution was replaced with freshly prepared feed solution in each cycle. The test results showed that after eight cycles, the removal rate remained above 97.62% without significant fluctuations, indicating a stable removal rate. This demonstrates that the Ag-Cu / polyamide nanofiltration composite catalytic membrane possesses stable catalytic activity.
[0035] The above results indicate that the Ag-Cu / polyamide nanofiltration composite catalytic membrane can efficiently remove 4-nitrophenol while maintaining a high rejection rate for divalent salts, and also exhibits good stability.
[0036] Experimental Example 5. Stability Testing of Ag-Cu / Polyamide Nanofiltration Composite Catalytic Membrane A batch of Ag-Cu / polyamide nanofiltration composite catalytic membranes was stored in pure water for 28 days. The membranes were removed periodically to test changes in pure water flux and 4-NP removal rate. The pure water flux of the membrane showed a slow upward trend, reaching a maximum of 108.10 L·m⁻¹ on day 28. -2 ·h -1 This is because, with prolonged exposure to water, a very small number of nanoparticles detach, increasing the hydrophilicity of the Ag-Cu / polyamide nanofiltration composite catalytic membrane. The removal rate of 4-NP by this membrane showed a slow decreasing trend, reaching its lowest point of 95.67% on day 28, indicating that the composite catalytic membrane still maintained relatively good catalytic performance.
[0037] Since the Ag-Cu / polyamide nanofiltration composite catalytic membrane is primarily loaded with silver nanoparticles, and the Cu mass percentage accounts for only 2% of the composite membrane, the main test focused on the release of silver from the water. The test results show that the cumulative concentration in the water was very low in the first week, increased slightly later, but still did not exceed the national standard. After 28 days of storage in water, the amount of metal nanoparticles detached was only 1.85%.
[0038] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.
Claims
1. A method for preparing a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, characterized in that: Using a PVDF membrane as a substrate, a polyamide thin layer is prepared on the PVDF membrane to obtain a polyamide nanofiltration composite membrane. Cu nanoparticles are then loaded onto the polyamide nanofiltration composite membrane via a photochemical reduction reaction. Subsequently, a displacement reaction with silver nitrate solution yields a polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles, i.e., an Ag-Cu / polyamide nanofiltration composite catalytic membrane. The Ag-Cu loading is 0.4-0.9 mg / cm³. 2 The percentage of Ag in the Ag-Cu is 81.16%-86.96%.
2. The method for preparing the polyamide nanofiltration composite catalytic membrane supported on Ag-Cu particles according to claim 1, characterized in that: Includes the following steps, A. Using a PVDF membrane as the substrate, place it in a membrane-forming frame, pour the aqueous PIP solution into the membrane-forming frame, and after fully wetting it, pour out the remaining PIP solution, air dry it naturally for 3-10 minutes, remove the residual solution, pour in the oil phase TMC solution, and after full contact, take out the PVDF membrane and place it in an oven at 40-80℃. After 10-20 minutes, take it out to obtain a polyamide nanofiltration composite membrane. B. Take a polyamide nanofiltration composite membrane with the filter side facing up and place it on the surface of an ethanol solution containing Cu(NO3)2 / benzophenone. Make sure the solution fully wets the polyamide nanofiltration composite membrane and place it in a closed reaction container to obtain a closed reaction system. C. Place the closed reaction system under ultraviolet light for 30-120 min. The photoinitiator benzophenone absorbs ultraviolet light and reacts with the co-initiator ethanol to generate active free radicals that reduce Cu ions in the solution to Cu nanoparticles, which are then loaded onto the surface and pores of the PVDF membrane. After the irradiation is complete, the membrane is removed and rinsed to obtain a Cu / polyamide nanofiltration composite membrane. D. The Cu / polyamide nanofiltration composite membrane is placed in an ethanol solution of silver nitrate to undergo a complete displacement reaction, resulting in an Ag-Cu / polyamide nanofiltration composite catalytic membrane.
3. The method for preparing the polyamide nanofiltration composite catalytic membrane supported on Ag-Cu particles according to claim 2, characterized in that: In step A, the concentration of the PIP solution is 0.05%-1%, and the concentration of the TMC is 0.05%-0.4%.
4. The method for preparing the polyamide nanofiltration composite catalytic membrane supported on Ag-Cu particles according to claim 2, characterized in that: In step B, the concentration of Cu(NO3)2 is 0.025-0.11 mol / L, and the concentration of benzophenone is 0.05-0.22 mol / L.
5. The method for preparing the polyamide nanofiltration composite catalytic membrane supported on Ag-Cu particles according to claim 4, characterized in that: In step B, the concentration ratio of Cu(NO3)2 to benzophenone is 1:
2.
6. The method for preparing the polyamide nanofiltration composite catalytic membrane supported on Ag-Cu particles according to claim 2, characterized in that: In step B, the closed reaction system is evacuated to 20 kPa.
7. The method for preparing the polyamide nanofiltration composite catalytic membrane supported on Ag-Cu particles according to claim 2, characterized in that: In step C, the power of the ultraviolet light source is 50W, and the wavelength of the ultraviolet light is 365nm.
8. The method for preparing the polyamide nanofiltration composite catalytic membrane supported on Ag-Cu particles according to claim 2, characterized in that: In step D, the concentration of the silver nitrate ethanol solution is 0.02-0.05 mol / L.
9. A polyamide nanofiltration composite catalytic membrane supported on Ag-Cu particles, characterized in that: The Ag-Cu particle-loaded polyamide nanofiltration composite catalytic membrane is prepared by the method described in any one of claims 1-8.
10. Application of polyamide nanofiltration composite catalytic membrane loaded with Ag-Cu particles in the catalytic reduction of nitrophenol compounds.