Zero-valent iron protection catalytic membrane as well as preparation method and application thereof

Abstract

The invention is applicable to the technical field of zero-valent iron protection, and provides a zero-valent iron protection catalytic membrane and a preparation method and application thereof, and the preparation method comprises the following steps: successively soaking a microfiltration membrane with water and ethanol, and drying for later use; the microfiltration membrane is sequentially subjected to polyelectrolyte introduction, iron precursor capture, in-situ growth of a zero-valent iron catalyst and rapid compact oxide layer protection, and finally nitrogen purging and filling are performed. Nanometer zero-valent iron is loaded on the membrane to improve the dispersity of the membrane, the problem that the membrane is prone to agglomeration is solved, meanwhile, the just prepared zero-valent iron catalytic membrane is pulled into an oxygen aeration reaction tank to be subjected to intentional oxidation protection, and the problem that the membrane is prone to inactivation is solved. The synthesis process is carried out at normal temperature and normal pressure under the aerobic condition, strong alkaline substances do not need to be added to form a passivation layer, the performance does not depend on a zero-valent iron composite material, the problem that zero-valent iron is prone to inactivation is solved in one step, and the method is low in cost, simple, environmentally friendly, remarkable in advantage and suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of zero-valent iron protection, and in particular relates to a zero-valent iron protection catalytic membrane and a preparation method and application thereof. Background Art

[0002] Nano-zero-valent iron (nZVI), characterized by its Fe(0) core and iron oxide shell, has shown great potential in the field of environmental remediation due to its high specific surface area, excellent reducing power, high activity, and easy availability. It has been proven to be able to effectively remove a variety of pollutants, including heavy metal ions (such as chromium (VI), lead (II), arsenic (III), etc.) and organic pollutants (such as trichloroethylene and phenol). Although nZVI has significant advantages and is widely used, it still faces challenges such as agglomeration and easy deactivation in practical applications. Therefore, how to simultaneously avoid the agglomeration and deactivation of nano-zero-valent iron has become a technical problem that needs to be solved in this field.

[0003] In existing technologies, nano-ZVI is often combined with materials such as biochar, carbon nanotubes, graphene, and fiber membranes to improve its dispersibility, increase its reactive sites, and address its tendency to agglomerate during practical applications. For example, methods for modifying nano-ZVI are disclosed in patent applications (CN118724236A, CN112156810A, CN116618073A, and CN119034693A). However, these methods only address the agglomeration problem, leaving unresolved the issue of its susceptibility to deactivation. Current methods for increasing the active lifespan of nano-ZVI include: protecting the ZVI core by forming a dense passivation layer using modified materials (e.g., patent applications CN117819695A and CN112875773A); and inhibiting the hydrogen evolution side reaction with water through methods such as nanocracks and sulfurization (e.g., patent applications CN118255426A and CN117401785A). However, most existing methods for forming dense oxide layers require the addition of strongly alkaline substances such as sodium hydroxide (such as patent applications CN112875773A and CN115634674A). On the one hand, this will cause a large amount of consumption and conversion of zero-valent iron, which will lose its electron transfer ability. On the other hand, the addition of strongly alkaline substances poses an environmental pollution risk. In addition, most existing methods for preparing zero-valent iron require an oxygen-free environment, and reactions are often carried out under an inert gas atmosphere to obtain stable zero-valent iron particles (such as patent applications CN116078383A and CN119387601A). Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a method for preparing a zero-valent iron protective catalytic membrane, aiming to solve the problems raised in the above background technology.

[0005] The embodiment of the present invention is achieved by a method for preparing a zero-valent iron protective catalytic membrane, comprising the following steps:

[0006] Soak the microfiltration membrane in water and ethanol successively, and dry it for later use;

[0007] The microfiltration membrane is pulled through the polymerization mother liquor reaction tank, the iron ion solution spray section, the reducing agent solution reaction tank and the oxygen aeration reaction tank in sequence, completing the processes of polyelectrolyte introduction, iron precursor capture, in-situ growth of zero-valent iron catalyst and rapid dense oxide layer protection. Finally, it is purged and filled with nitrogen and packaged for use.

[0008] Preferably, the microfiltration membrane is one or more of polysulfone, polyethersulfone, polyvinylidene fluoride, and cellulose acetate.

[0009] Preferably, the polymerization mother solution reaction tank includes a polyelectrolyte precursor, a photoinitiator, a cross-linking agent, and an auxiliary agent, and the microfiltration membrane residence time is 10 to 30 seconds;

[0010] Wherein, the polyelectrolyte precursor is one or more of sodium fumarate, sodium maleate, and sodium limonate;

[0011] The photoinitiator is Irgacure 2959;

[0012] The cross-linking agent is one or more of oligomeric proanthocyanidins, tannic acid, and tea polyphenols;

[0013] The auxiliary agent is sodium citrate;

[0014] The mass ratio of the polyelectrolyte precursor, the photoinitiator, the crosslinking agent and the auxiliary agent is 1:0.02-0.05:0.01-0.025:0.05-0.2.

[0015] Preferably, the solution sprayed in the iron ion solution spray section is one or more of ferric acetate, ferric chloride, and ferric nitrate, with a concentration of 100-400 ppm, a spray flow rate of 50-200 mL / min, and a spray time of 20-100 s.

[0016] Preferably, the reducing agent solution reaction tank includes a reducing agent and an auxiliary agent, and the microfiltration membrane residence time is 10 to 15 minutes;

[0017] In fact, the reducing agent is one or more of ascorbic acid, gallic acid, and ellagic acid;

[0018] The auxiliary agent is one or more of kakadu plum extract, gallnut extract and cat's claw extract.

[0019] Preferably, the flow rate of oxygen aeration in the oxygen aeration reaction tank is 0.1-0.5 L / min, the temperature is 15-35° C., and the residence time of the microfiltration membrane is 3-20 min.

[0020] Another object of an embodiment of the present invention is to provide a zero-valent iron protective catalytic membrane, which is prepared using the above-mentioned preparation method.

[0021] Another object of an embodiment of the present invention is to provide an application of the above-mentioned zero-valent iron protective catalytic membrane in the treatment of chlorinated hydrocarbon wastewater.

[0022] The present invention provides a method for preparing a zero-valent iron protective catalytic membrane. By modifying the polymer microfiltration membrane support layer, nano-zero-valent iron (nZVI) is guided to disperse and grow in situ within the membrane pores to construct a catalytically active layer, thereby addressing the problem of nZVI agglomeration at the source. Furthermore, a green oxidation method is used to passivate the zero-valent iron surface, forming a stable protective layer that effectively extends its reactive lifespan and prevents rapid deactivation. This method is simple to operate, low-cost, environmentally friendly, and has promising prospects for industrial application.

[0023] The catalytic membrane prepared by this preparation method not only improves the dispersibility and stability of nZVI, but also effectively exposes more catalytic active sites, thereby enhancing its catalytic efficiency. Furthermore, the membrane is detachable and easily recyclable, making it suitable for the continuous treatment of chlorine-containing organic wastewater, significantly improving the sustainability and operational flexibility of engineering applications.

[0024] This preparation method is environmentally friendly and efficient, using environmentally friendly reducing agents and additives. High-performance nZVI can be prepared without the addition of strong alkaline substances. This method not only maintains mild reaction conditions but also significantly increases the active lifespan of the catalytic particles. Furthermore, this method has low dependence on support materials, avoiding the high cost of traditional composite materials, and exhibits excellent economic and versatility.

[0025] The catalytic membrane prepared by this preparation method has efficient and stable chlorinated organic degradation capabilities, and exhibits excellent degradation performance in the process of treating chlorinated organics (such as chlorinated hydrocarbon epoxy resin wastewater). In the initial stage, it can achieve a 96% removal rate of epichlorohydrin and maintain a removal rate of more than 75% after 180 hours of continuous operation, reflecting excellent long-term stability and treatment continuity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flow chart of a method for preparing a zero-valent iron protective catalytic membrane provided by an embodiment of the present invention;

[0027] Figure 2The initial removal rate of epichlorohydrin and the reaction activity life of the materials prepared in Examples 1-5 and Comparative Examples 1-3 of the present invention in a simulated actual water environment;

[0028] Figure 3 These are TEM images of the catalytic particles prepared in Example 4 of the present invention and Comparative Example 3 before and after treating epoxy resin wastewater. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] A zero-valent iron protective catalytic membrane, the preparation method of which is as follows Figure 1 As shown, the specific steps include:

[0031] (1) Soak a commercial microfiltration membrane (one or more of polysulfone, polyethersulfone, polyvinylidene fluoride, and cellulose acetate) in water and ethanol for 4 to 12 hours, then dry it for later use;

[0032] (2) The commercial microfiltration membrane is sequentially pulled through the polymerization mother liquor reaction tank (which includes a polyelectrolyte precursor, a polymerization agent, and an auxiliary agent; the polyelectrolyte precursor is one or more of sodium fumarate, sodium maleate, and sodium limonenedioate; the polymerization agent includes a photoinitiator and a cross-linking agent, wherein the photoinitiator is Irgacure 2959, the cross-linking agent is one or more of oligomeric proanthocyanidins, tannic acid, and tea polyphenols, and the auxiliary agent is sodium citrate; the mass ratio of the polyelectrolyte precursor, the initiator, the cross-linking agent, and the auxiliary agent is 1:0.02~0.05:0.01~0.025:0.05~0.2; the wavelength of the light excitation section is 365 nm, the light source is an LED lamp, and the residence time is 10~30 seconds), the iron ion solution spraying section (the spraying solution is one or more of ferric acetate, ferric chloride, and ferric nitrate, with a concentration of 100~400 ppm; the spraying flow rate is 50~200 mL / min, and the spraying time is 20~100 s), reducing agent solution reaction tank (including reducing agent and auxiliary agent, the reducing agent is one or more of ascorbic acid, gallic acid, and ellagic acid, and the auxiliary agent is one or more of kakadu plum extract, gallnut extract, and cat's claw vine extract, and the residence time is 10-15 minutes; since the natural reducing agents ascorbic acid, gallic acid, and ellagic acid, such as enol or phenolic acids, are insufficient to reduce iron ions to zero-valent iron, the addition of condensed tannin reducing agents such as kakadu plum, gallnut, and cat's claw vine can complete the green reduction of zero-valent iron) and oxygen aeration reaction tank (the oxygen aeration flow rate is 0.1-0.5 L / min, temperature 15~35℃, residence time 3~20 minutes. This process does not require the addition of strong alkaline substances such as sodium hydroxide, does not require synthesis conditions such as oxygen-free and high temperature, and its performance does not rely on zero-valent iron composite materials, solving the problem of easy deactivation of zero-valent iron in one step). It thus completes the introduction of polyelectrolyte, capture of iron precursor, in-situ growth of zero-valent iron catalyst and rapid dense oxide layer protection in sequence, and finally is purged and filled with nitrogen for packaging and standby.

[0033] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0034] Example 1: A zero-valent iron protective catalytic membrane, the preparation method of which comprises the following steps:

[0035] (1) Soak the commercial microfiltration membrane polysulfone in water and ethanol for 8 hours, and then dry it for later use;

[0036] (2) The polyelectrolyte precursor sodium fumarate, polymerization agent Irgacure 2959, cross-linking agent oligomeric proanthocyanidin and auxiliary agent sodium citrate were mixed in a reaction tank according to the mass ratio of functional group monomer, photoinitiator, cross-linking agent and auxiliary agent of 1:0.03:0.02:0.015. The commercial microfiltration membrane was placed on a roller track and was first immersed and then passed through the above reaction tank by traction. Air purge was set at the outlet. Then it entered the light initiation section with a light source of LED light and a wavelength of 365 nm and stayed for 30 seconds to complete the polymerization of the electrolyte precursor; then the membrane was sprayed with ferric acetate solution with a concentration of 400 ppm at a spray flow rate of 100 mL / min for 20 s, immersed and passed through the ascorbic acid reducing agent solution containing kakadu plum extract as an auxiliary agent, and the reduction time was 15 minutes; the above catalytic membrane was directly pulled through the oxygen aeration reaction tank with an oxygen aeration flow rate of 0.1 L / min and a temperature of 25°C for 3 minutes, and finally filled with nitrogen purge and packaged for use.

[0037] Example 2: A zero-valent iron protective catalytic membrane, the preparation method of which comprises the following steps:

[0038] (1) Soak the commercial microfiltration membrane polysulfone in water and ethanol for 8 hours, and then dry it for later use;

[0039] (2) The polyelectrolyte precursor sodium fumarate, polymerization agent Irgacure 2959, cross-linking agent oligomeric proanthocyanidin and auxiliary agent sodium citrate were mixed in a reaction tank according to the mass ratio of functional group monomer, photoinitiator, cross-linking agent and auxiliary agent of 1:0.03:0.02:0.015. The commercial microfiltration membrane was placed on a roller track and was first immersed and then passed through the above reaction tank by traction. Air purge was set at the outlet. Then it entered the light initiation section with a light source of LED light and a wavelength of 365 nm and stayed for 30 seconds to complete the polymerization of the electrolyte precursor; then the membrane was sprayed with ferric acetate solution with a concentration of 400 ppm at a spray flow rate of 100 mL / min for 20 s, immersed and passed through the ascorbic acid reducing agent solution containing kakadu plum extract as an auxiliary agent, and the reduction time was 15 minutes; the above catalytic membrane was directly pulled through the oxygen aeration reaction tank with an oxygen aeration flow rate of 0.5 L / min and a temperature of 25°C for 3 minutes, and finally filled with nitrogen purge and packaged for use.

[0040] Example 3: A zero-valent iron protective catalytic membrane, the preparation method of which comprises the following steps:

[0041] (1) Soak the commercial microfiltration membrane polysulfone in water and ethanol for 8 hours, and then dry it for later use;

[0042] (2) The polyelectrolyte precursor sodium fumarate, polymerization agent Irgacure 2959, crosslinking agent oligomeric proanthocyanidin and auxiliary agent sodium citrate were mixed in a reaction tank according to the mass ratio of functional group monomer, photoinitiator, crosslinking agent and auxiliary agent of 1:0.03:0.02:0.015. The commercial microfiltration membrane was placed on a roller track and was first immersed and then passed through the above reaction tank by pulling. Air was set at the outlet. Then it entered the light initiation section with a light source of LED light and a wavelength of 365 nm and stayed for 30 seconds to complete the polymerization of the electrolyte precursor. After that, the membrane was sprayed with 400 ppm ferric acetate solution at a spray flow rate of 100 mL / min for 20 seconds, immersed and passed through the ascorbic acid reducing agent solution containing kakadu plum extract auxiliary agent, and the reduction time was 15 minutes. The above catalytic membrane was directly pulled through the oxygen aeration reaction tank with an oxygen aeration flow rate of 0.5 L / min and a temperature of 25°C for 5 minutes. Finally, it was filled with nitrogen purge and packaged for use.

[0043] Example 4: A zero-valent iron protective catalytic membrane, the preparation method of which comprises the following steps:

[0044] (1) Soak the commercial microfiltration membrane polysulfone in water and ethanol for 8 hours, and then dry it for later use;

[0045] (2) The polyelectrolyte precursor sodium fumarate, polymerization agent Irgacure 2959, cross-linking agent oligomeric proanthocyanidin and auxiliary agent sodium citrate were mixed in a reaction tank according to the mass ratio of functional group monomer, photoinitiator, cross-linking agent and auxiliary agent of 1:0.03:0.02:0.015. The commercial microfiltration membrane was placed on a roller track and was first immersed in and then passed through the above-mentioned reaction tank by traction. Air was set at the outlet and then entered the light initiation section with a light source of LED light and a wavelength of 365 nm and stayed for 30 seconds to complete the polymerization of the electrolyte precursor. After that, the membrane was sprayed with ferric acetate solution with a concentration of 400 ppm at a spray flow rate of 100 mL / min for 20 s, immersed in and passed through the ascorbic acid reducing agent solution containing kakadu plum extract as an auxiliary agent, and the reduction time was 15 minutes. The above-mentioned catalytic membrane was directly pulled through an oxygen aeration reaction tank with an oxygen aeration flow rate of 0.5 L / min and a temperature of 25° C. for 10 minutes, and finally purged and filled with nitrogen, and then packaged for use.

[0046] Example 5: A zero-valent iron protective catalytic membrane, the preparation method of which comprises the following steps:

[0047] (1) Soak the commercial microfiltration membrane polysulfone in water and ethanol for 8 hours, and then dry it for later use;

[0048] (2) The polyelectrolyte precursor sodium fumarate, polymerization agent Irgacure 2959, cross-linking agent oligomeric proanthocyanidin and auxiliary agent sodium citrate were mixed in a reaction tank according to the mass ratio of functional group monomer, photoinitiator, cross-linking agent and auxiliary agent of 1:0.03:0.02:0.015. The commercial microfiltration membrane was placed on a roller track and was first immersed in and then passed through the above-mentioned reaction tank by traction. Air was set at the outlet and then entered the light initiation section with a light source of LED light and a wavelength of 365 nm and stayed for 30 seconds to complete the polymerization of the electrolyte precursor. After that, the membrane was sprayed with ferric acetate solution with a concentration of 400 ppm at a spray flow rate of 100 mL / min for 20 s, immersed in and passed through the ascorbic acid reducing agent solution containing kakadu plum extract as an auxiliary agent, and the reduction time was 15 minutes. The above-mentioned catalytic membrane was directly pulled through an oxygen aeration reaction tank with an oxygen aeration flow rate of 0.5 L / min and a temperature of 25° C. for 20 minutes, and finally purged and filled with nitrogen, and then packaged for use.

[0049] Comparative Example 1: Commercial microfiltration membrane polysulfone was soaked in water and ethanol for 8 hours, and then dried for later use.

[0050] Comparative Example 2: A nanometer zero-valent iron catalytic particle, the preparation method of which comprises the following steps:

[0051] (1) Soak the commercial microfiltration membrane polysulfone in water and ethanol for 8 hours, and then dry it for later use;

[0052] (2) The polyelectrolyte precursor sodium fumarate, polymerization agent Irgacure 2959, cross-linking agent oligomeric proanthocyanidin and auxiliary agent sodium citrate were mixed in a reaction tank according to the mass ratio of functional group monomer, photoinitiator, cross-linking agent and auxiliary agent of 1:0.03:0.02:0.015. The commercial microfiltration membrane was placed on a roller track and was first immersed in and then passed through the above reaction tank by traction. Air was set at the outlet. Then it entered the light initiation section with a light source of LED light and a wavelength of 365 nm and stayed for 30 seconds to complete the polymerization of the electrolyte precursor. After that, the membrane was sprayed with ferric acetate solution with a concentration of 400 ppm at a spray flow rate of 100 mL / min for 20 s, immersed in and passed through the reducing agent solution containing ascorbic acid for 15 minutes, and finally filled with nitrogen purge and packaged for use.

[0053] Comparative Example 3: A nanometer zero-valent iron catalytic particle, the preparation method of which comprises the following steps:

[0054] (1) Soak the commercial microfiltration membrane polysulfone in water and ethanol for 8 hours, and then dry it for later use;

[0055] (2) The polyelectrolyte precursor sodium fumarate, polymerization agent Irgacure 2959, cross-linking agent oligomeric proanthocyanidin and auxiliary agent sodium citrate were mixed in a reaction tank according to the mass ratio of functional group monomer, photoinitiator, cross-linking agent and auxiliary agent of 1:0.03:0.02:0.015. The commercial microfiltration membrane was placed on a roller track and was first immersed in and then passed through the above reaction tank by traction. Air was set at the outlet. Then it entered the light initiation section with a light source of LED light and a wavelength of 365 nm and stayed for 30 seconds to complete the polymerization of the electrolyte precursor. After that, the membrane was sprayed with ferric acetate solution with a concentration of 400 ppm at a spray flow rate of 100 mL / min for 20 s, immersed in and passed through the ascorbic acid reducing agent solution containing kakadu plum extract as an auxiliary agent, and the reduction time was 15 minutes. Finally, it was purged with nitrogen and filled and packaged for use.

[0056] Performance testing:

[0057] 1. TEM scanning was performed on the nanometer zero-valent iron catalytic particles prepared in Comparative Example 3, and the results were as follows: Figure 3 As shown in a, the nano zero-valent iron catalytic particles were used to treat epoxy resin wastewater for 180 h and then TEM scanning was performed to obtain the results as shown in Figure 3 b; and the TEM image of the nano zero-valent iron catalytic particles prepared in Example 4 after treating epoxy resin wastewater for 180 h is shown in FIG. Figure 3 As shown in c;

[0058] according to Figure 3 It can be seen that the average diameter of the zero-valent iron catalytic particles prepared in Comparative Example 3 without intentional oxidation protection is about 49.5 nm, the distribution is concentrated, and it is easy to agglomerate. 0 The core was completely oxidized and corroded, losing its basic spherical shell structure; however, after treating epoxy resin wastewater for 180 hours, the catalytic particles intentionally oxidized and protected in Example 4 had intact spherical shell structures, with diameters ranging from 40 to 100 nm and relatively uniform distribution. This shows that the intentionally oxidized and protected zero-valent iron catalytic particles can inhibit iron agglomeration, reduce side reactions, and increase their reactive lifespan.

[0059] 2. Add epichlorohydrin, sodium dihydrogen phosphate, sodium chloride, and humic acid to distilled water to simulate the actual water environment. The resulting solution has an epichlorohydrin concentration of 1 mg / L, a humic acid concentration of 20 mg / L, a pH of 7.5, and a conductivity of 1200 μS / cm.

[0060] The membrane samples prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were connected to the feed and discharge ports, and the above-mentioned solutions simulating the actual water environment were respectively introduced for testing. The test pressure was 0.2 MPa, and the purge and trap method and gas chromatography-mass spectrometry were used for quantitative testing. The results are shown in FIG. Figure 2 As shown;

[0061] according to Figure 2 The data of Comparative Examples 1 to 3 show that the commercial microfiltration membrane without catalytic functionalization has only a 3% epichlorohydrin removal rate, which can be regarded as basically incapable of treating epichlorohydrin. In addition, the only 4% reduction of epichlorohydrin removal rate in Comparative Example 2 shows that the additive is an indispensable part of the preparation of nano-zero-valent iron.

[0062] By increasing the oxygen aeration flow rate and oxygen aeration time, the reactive lifespan of the catalytic particles obtained in Examples 1 to 5 gradually increased to 180 hours, which is significantly superior to the catalytic particles obtained in Comparative Example 3. This shows that oxidation protection can extend the reactive lifespan of catalytic particles.

[0063] The data of Examples 1 and 2 show that the oxygen aeration flow rate has an impact on the reaction activity life. As the oxygen aeration flow rate increases to 0.5 L / min, the reaction activity life of the zero-valent iron catalytic particles t 75 (t 75 The operating active life (defined as the period during which the reaction removal efficiency remains above 75% of the initial removal efficiency) gradually increased from 0.6 h to 35 h;

[0064] It can be seen from the data of Examples 2 to 4 that the length of the intentional oxidation protection time of the zero-valent iron catalytic particles is a key factor in improving the reactive life of the zero-valent iron catalytic particles. When the intentional oxidation protection time is increased to 10 minutes, a continuous zero-valent iron protective layer is formed, and the reactive life of the catalytic particles t 75 Increased to 180 hours;

[0065] It can be seen from Examples 4 and 5 that when the intentional oxidation protection time is increased to 20 minutes, the reactive life span t 75 The improvement of epichlorohydrin removal rate was not obvious.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a zero-valent iron protective catalytic membrane, characterized in that: The following steps are involved: Soak the microfiltration membrane in water and ethanol successively, and dry it for later use; The microfiltration membrane is pulled through the polymerization mother liquor reaction tank, the iron ion solution spray section, the reducing agent solution reaction tank and the oxygen aeration reaction tank in sequence, completing the processes of polyelectrolyte introduction, iron precursor capture, in-situ growth of zero-valent iron catalyst and rapid dense oxide layer protection. Finally, it is purged and filled with nitrogen and packaged for use.

2. The method for preparing a zero-valent iron protective catalytic membrane according to claim 1, characterized in that: The microfiltration membrane is one or more of polysulfone, polyethersulfone, polyvinylidene fluoride and cellulose acetate.

3. The method for preparing a zero-valent iron protective catalytic membrane according to claim 1, characterized in that: The polymerization mother solution reaction tank includes a polyelectrolyte precursor, a photoinitiator, a cross-linking agent, and an auxiliary agent, and the microfiltration membrane residence time is 10 to 30 seconds; Wherein, the polyelectrolyte precursor is one or more of sodium fumarate, sodium maleate, and sodium limonate; The photoinitiator is Irgacure 2959; The cross-linking agent is one or more of oligomeric proanthocyanidins, tannic acid, and tea polyphenols; The auxiliary agent is sodium citrate; The mass ratio of the polyelectrolyte precursor, the photoinitiator, the crosslinking agent and the auxiliary agent is 1:0.02-0.05:0.01-0.025:0.05-0.

2.

4. The method for preparing a zero-valent iron protective catalytic membrane according to claim 1, characterized in that: The solution sprayed in the iron ion solution spray section is one or more of ferric acetate, ferric chloride, and ferric nitrate, with a concentration of 100-400 ppm, a spray flow rate of 50-200 mL / min, and a spray time of 20-100 s.

5. The method for preparing a zero-valent iron protective catalytic membrane according to claim 1, wherein: The reducing agent solution reaction tank includes a reducing agent and an auxiliary agent, and the microfiltration membrane residence time is 10 to 15 minutes; In fact, the reducing agent is one or more of ascorbic acid, gallic acid, and ellagic acid; The auxiliary agent is one or more of kakadu plum extract, gallnut extract and cat's claw extract.

6. The method for preparing a zero-valent iron protective catalytic membrane according to claim 1, characterized in that: The oxygen aeration flow rate in the oxygen aeration reaction tank is 0.1-0.5 L / min, the temperature is 15-35° C., and the microfiltration membrane residence time is 3-20 min.

7. A zero-valent iron protective catalytic membrane, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the zero-valent iron protective catalytic membrane according to claim 7 in the treatment of chlorinated hydrocarbon wastewater.

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