Preparation method and application of electric control separation membrane for electrochemical coupling system

Abstract

The invention discloses a preparation method and application of an electric control separation membrane for an electrochemical coupling system, and belongs to the technical field of electrochemical water treatment. The preparation method of the electric control separation membrane comprises the following steps: placing a conductive membrane substrate in a mixed solution of a cobalt source, urea and ammonium fluoride, carrying out a hydrothermal reaction, and then carrying out a phosphating reaction with a phosphorus source in an inert atmosphere to obtain the electric control separation membrane. The electric control separation membrane has the performance of efficiently removing pollutants and the performance of cleaning the membrane.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical water treatment, and in particular to a method for preparing an electrically controlled separation membrane for an electrochemical coupling system and its application. Background Art

[0002] Wastewater generated from processes such as petroleum refining, explosives production, metal processing, and fertilizer production all contain varying levels of nitrate. Large amounts of nitrate wastewater, combined with the natural organic pollutant humic acid (HA), can form complex pollutants, severely contaminating groundwater, rivers, and lakes, causing eutrophication and potentially posing significant health risks. Currently, common wastewater treatment technologies include electrocoagulation, electrocatalytic reduction, and membrane separation. Electrocoagulation, while requiring simple equipment and generating minimal waste, is easily combined and used for the treatment of suspended pollutants, but its effectiveness in removing nitrate is minimal. Electrocatalytic reduction, using hydrogen generated by electrolysis as a reducing agent, effectively reduces nitrate to nitrite, and ultimately to nitrogen or ammonia nitrogen. However, it is unable to treat large organic pollutants in water. Membrane separation can precisely separate complex pollutants by regulating membrane pore size, but membrane fouling, which can occur over long periods of operation, significantly impacts separation efficiency.

[0003] Single water treatment methods have both advantages and limitations. Combining multiple electrochemical methods with other methods, such as membrane separation technology, to form an electrochemical coupling system can effectively compensate for their respective shortcomings. However, electrochemical coupling systems are not widely used in the treatment of nitrate-contaminated water. The reasons are: the electrocatalytic reductant has poor selectivity for the selective reduction of nitrate to ammonia and low energy efficiency, and the hydrogen evolution reaction during water electrolysis easily competes with the reduction reaction; in the membrane separation process, the membrane pore size regulation and membrane fouling problems cannot be effectively and timely addressed, and the membrane's cyclic stability is poor. Therefore, it is crucial to find a conductive membrane that can achieve both efficient pollutant removal and membrane cleaning in an electrochemical coupling system. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing an electrically controlled separation membrane for an electrochemical coupling system and its application, so as to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention: a method for preparing an electrically controlled separation membrane, comprising the following steps:

[0007] The conductive membrane substrate is placed in a mixed solution of a cobalt source, urea and ammonium fluoride, and after a hydrothermal reaction, a phosphating reaction is carried out together with a phosphorus source under an inert atmosphere to obtain the electrically controlled separation membrane.

[0008] Ammonium fluoride can control the reaction rate and stability; urea as a precipitant promotes the precipitation of the target product.

[0009] Furthermore, the molar ratio of the cobalt source, urea and ammonium fluoride is 2:(8-11):5.

[0010] Furthermore, the cobalt source includes cobalt nitrate.

[0011] Furthermore, the preparation method of the mixed solution of the cobalt source, urea and ammonium fluoride includes the following steps: mixing cobalt nitrate, urea, ammonium fluoride and water in a ratio of 8 mmol: 32-44 mmol: 20 mmol: 80-100 mL, magnetically stirring for 1 h to 1.5 h, and mixing evenly to obtain the mixed solution.

[0012] Furthermore, the temperature of the hydrothermal reaction is 110-120° C., and the time is 16-18 hours.

[0013] Furthermore, the temperature of the hydrothermal reaction is 110° C. and the time is 17 h.

[0014] Furthermore, the inert atmosphere is a nitrogen atmosphere.

[0015] Furthermore, the temperature of the phosphating reaction (low-temperature phosphating) is 300-350° C., and the time is 1-2 hours;

[0016] The phosphorus source includes sodium hypophosphite.

[0017] Furthermore, the mass ratio of the conductive film substrate area to the phosphorus source is 25 cm 2 :0.45g.

[0018] Furthermore, the phosphating reaction has a heating rate of 5°C / min, a temperature of 300°C, and a time of 1 hour.

[0019] The present invention utilizes a simple in-situ growth technology to load CoP on a conductive membrane substrate, thereby obtaining an electrically controlled separation membrane with both high-efficiency pollutant removal and membrane cleaning performance, and has the advantage of a simple preparation process.

[0020] The electrically controlled separation membrane prepared by the present invention has the advantages of good stability and small pore size (which can effectively intercept humic acid molecules). The CoP nanostructure on the membrane surface can greatly promote the generation of atomic hydrogen (H*). Atomic hydrogen (H*) has strong reducing properties and can convert NO3 -Reduced to NH3; the electrically controlled separation membrane and the electrochemical coupling system are integrated into the reaction device, and their respective advantages are well utilized through potential regulation. The anode removes humic acid through electrocoagulation in conjunction with the cathode membrane separation technology, and the cathode degrades nitrates through electroreduction technology. In addition, the voltage can be adjusted during the separation process to achieve the dual goals of efficient removal of pollutants and membrane cleaning.

[0021] Furthermore, the conductive film substrate is selected from one of stainless steel mesh (SSM), titanium mesh (Ti), copper mesh and nickel mesh (Ni).

[0022] The second technical solution of the present invention: an electrically controlled separation membrane prepared by the above preparation method.

[0023] The third technical solution of the present invention: an application of the above-mentioned electrically controlled separation membrane in the construction of an electrochemical coupling system.

[0024] Furthermore, the electrochemical coupling system uses the electrically controlled separation membrane as the cathode and the aluminum plate as the anode, is connected with a DC power supply, and the distance between the anode and cathode is 1.6 cm. After power is applied and water is added, the target system is obtained.

[0025] Furthermore, the DC power supply adopts a constant voltage power supply mode with a voltage of 1.4V.

[0026] Technical solution 4 of the present invention: an application of the above-mentioned electrically controlled separation membrane in the preparation of an electrochemical coupled reactor.

[0027] Furthermore, the electrochemical coupling reactor uses the electrically controlled separation membrane as a cathode and the aluminum plate as an anode.

[0028] Furthermore, the area of the electrically controlled separation membrane is 25 cm 2 ; The area of the aluminum plate is 36cm 2 The total volume of the reactor is 80 cm 2 .

[0029] The fifth technical solution of the present invention: an application of the above-mentioned electrochemical coupling reactor or electrochemical coupling system in the treatment of nitrate-complex polluted water.

[0030] The present invention discloses the following technical effects:

[0031] (1) The electrically controlled separation membrane of the present invention has the performance of both efficient removal of pollutants and membrane cleaning (all surface pollutants can be removed by applying 2V power for 10 minutes).

[0032] (2) The electrically controlled separation membrane of the present invention uses a conductive metal as a substrate, and has the advantages of low raw material cost, easy acquisition, good conductivity and mechanical stability.

[0033] (3) The pore size of the electrically controlled separation membrane prepared by the present invention is about 7 to 8 μm; the surface is covered with a nanostructured CoP array, which can provide abundant active sites and enhance the efficiency of electron transfer and mass transfer, thereby accelerating the reduction of nitrate.

[0034] (4) The electrically controlled separation membrane prepared by the present invention has a faradaic efficiency of up to 95% for ammonia during electrochemical testing, high selectivity, and low energy consumption (energy consumption is 0.011Wh).

[0035] (5) The electrochemical coupling system constructed by the present invention includes the electrocoagulation effect of the anode and the electroreduction effect of the cathode, which increases the applicability of the system, overcomes the disadvantage of a single technology, and has high cycle stability (in a long-term test of 144 hours, it was found that when a voltage of 2V was applied to the membrane for 10 minutes every 24 hours, the membrane flux recovered to more than 95% of the pre-cleaning level, and the nitrate removal rate basically remained in the optimal state), and the water treatment efficiency was greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 This is a scanning electron microscope image of the electrically controlled separation membrane (i.e., CoP / SSM) prepared in Example 1;

[0038] Figure 2 This is the EDS image of the electrically controlled separation membrane (i.e., CoP / SSM) prepared in Example 1;

[0039] Figure 3 XRD pattern of the electrically controlled separation membrane (i.e., CoP / SSM) prepared in Example 1;

[0040] Figure 4 The linear sweep voltammetry curves of the electrically controlled separation membrane (i.e., CoP / SSM) and SSM prepared in Example 1 in a 0.1 mol / L NaNO3 solution are shown;

[0041] Figure 5 Schematic diagram of an electrochemical coupling system prepared using the electrically controlled separation membrane (i.e., CoP / SSM) prepared in Example 1;

[0042] Figure 6 This is a diagram showing the removal effect of nitrate in water contaminated with humic acid and nitrate by the electrically controlled separation membrane (i.e., CoP / SSM) prepared in Example 1 at different current densities;

[0043] Figure 7 This is a diagram showing the removal effect of humic acid in water contaminated with humic acid and nitrate by the electrically controlled separation membrane (i.e., CoP / SSM) prepared in Example 1 at different current densities. DETAILED DESCRIPTION

[0044] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0045] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0046] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0047] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0048] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0049] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0050] Example 1

[0051] A method for preparing an electrically controlled separation membrane for an electrochemical coupling system:

[0052] (1) A stainless steel mesh (SSM) with an aperture of 800 mesh was selected as the conductive membrane substrate (size 5 cm × 5 cm). The conductive membrane substrate was first washed with 3M HCl, then with anhydrous ethanol, and finally with ultrapure water, and placed in an oven to dry for use.

[0053] (2) 8 mmol of cobalt nitrate hexahydrate, 40 mmol of urea, and 20 mmol of ammonium fluoride (the molar ratio of the three drugs is 2:10:5) were dissolved in 80 mL of water and magnetically stirred for 1 h (stirring speed was 800 r / min) until the mixture was uniformly mixed to obtain a mixed solution.

[0054] (3) The conductive film substrate dried in step (1) was placed in the mixed solution prepared in step (2), and the mixture was sealed in a polyethylene autoclave and hydroheated at 110° C. for 17 h. After cooling and removal, the mixture was repeatedly rinsed with deionized water to obtain a conductive film substrate with a pink-purple CoP precursor grown thereon.

[0055] (4) The conductive film substrate on which the pink-purple CoP precursor was grown was freeze-dried and placed downstream of the magnetic boat. 0.45 g of sodium hypophosphite was placed upstream of the magnetic boat and placed in a tubular furnace. The temperature was raised to 300 °C at a heating rate of 5 °C / min under a nitrogen atmosphere and kept warm for phosphating for 1 h (the surface of the conductive film substrate changed from pink-purple to black, and the precursor on the surface of the conductive film substrate was converted to CoP). The membrane was cooled to room temperature, washed with deionized water, and freeze-dried to obtain an electrically controlled separation membrane (i.e., CoP / SSM) with a pore size of approximately 7.22 μm.

[0056] Example 2

[0057] A method for preparing an electrically controlled separation membrane for an electrochemical coupling system:

[0058] (1) A stainless steel mesh (SSM) with an aperture of 800 mesh was selected as the conductive membrane substrate (size 5 cm × 5 cm). The conductive membrane substrate was first washed with 3M HCl, then with anhydrous ethanol, and finally with ultrapure water, and placed in an oven to dry for use.

[0059] (2) 8 mmol of cobalt nitrate hexahydrate, 40 mmol of urea, and 20 mmol of ammonium fluoride (the molar ratio of the three drugs is 2:10:5) were dissolved in 80 mL of water and magnetically stirred for 1 h (stirring speed was 800 r / min) until the mixture was uniformly mixed to obtain a mixed solution.

[0060] (3) The conductive film substrate dried in step (1) was placed in the mixed solution prepared in step (2), and the mixture was sealed in a polyethylene autoclave and heated at 120°C for 17 hours. After cooling, the substrate was taken out and repeatedly rinsed with deionized water to obtain a conductive film substrate with a pink-purple CoP precursor grown thereon.

[0061] (4) The conductive film substrate on which the pink-purple CoP precursor was grown was freeze-dried and placed downstream of the magnetic boat. 0.45 g of sodium hypophosphite was placed upstream of the magnetic boat and placed in a tubular furnace. The temperature was raised to 300 °C at a heating rate of 5 °C / min under a nitrogen atmosphere and kept warm for phosphating for 1 h (the surface of the conductive film substrate changed from pink-purple to black, and the precursor on the surface of the conductive film substrate was converted to CoP). The membrane was cooled to room temperature, washed with deionized water, and freeze-dried to obtain an electrically controlled separation membrane (i.e., CoP / SSM) with a pore size of approximately 6.96 μm.

[0062] Example 3

[0063] A method for preparing an electrically controlled separation membrane for an electrochemical coupling system:

[0064] (1) A stainless steel mesh (SSM) with an aperture of 800 mesh was selected as the conductive membrane substrate (size 5 cm × 5 cm). The conductive membrane substrate was first washed with 3M HCl, then with anhydrous ethanol, and finally with ultrapure water, and placed in an oven to dry for use.

[0065] (2) 8 mmol of cobalt nitrate hexahydrate, 40 mmol of urea, and 20 mmol of ammonium fluoride (the molar ratio of the three drugs is 2:10:5) were dissolved in 80 mL of water and magnetically stirred for 1 h (stirring speed was 800 r / min) until the mixture was uniformly mixed to obtain a mixed solution.

[0066] (3) The conductive film substrate dried in step (1) was placed in the mixed solution prepared in step (2), and the mixture was sealed together in a polyethylene autoclave and hydroheated at 110° C. for 18 h. After cooling, the substrate was taken out and repeatedly rinsed with deionized water to obtain a conductive film substrate with a pink-purple CoP precursor grown thereon.

[0067] (4) The conductive film substrate on which the pink-purple CoP precursor was grown was freeze-dried and placed downstream of the magnetic boat. 0.45 g of sodium hypophosphite was placed upstream of the magnetic boat and placed in a tubular furnace. The temperature was raised to 300 °C at a heating rate of 5 °C / min under a nitrogen atmosphere and kept warm for phosphating for 1 h (the surface of the conductive film substrate changed from pink-purple to black, and the precursor on the surface of the conductive film substrate was converted to CoP). The membrane was cooled to room temperature, washed with deionized water, and freeze-dried to obtain an electrically controlled separation membrane (i.e., CoP / SSM) with a pore size of approximately 6.90 μm.

[0068] Example 4

[0069] A method for preparing an electrically controlled separation membrane for an electrochemical coupling system:

[0070] (1) A stainless steel mesh (SSM) with an aperture of 800 mesh was selected as the conductive membrane substrate (size 5 cm × 5 cm). The conductive membrane substrate was first washed with 3M HCl, then with anhydrous ethanol, and finally with ultrapure water, and placed in an oven to dry for use.

[0071] (2) 8 mmol of cobalt nitrate hexahydrate, 40 mmol of urea and 20 mmol of ammonium fluoride (the molar ratio of the three drugs is 2:10:5) are dissolved in 80% water and magnetically stirred for 1 h (stirring speed is 800 r / min) until the mixture is uniformly mixed to obtain a mixed solution.

[0072] (3) The conductive film substrate dried in step (1) was placed in the mixed solution prepared in step (2), and the mixture was sealed in a polyethylene autoclave and hydroheated at 120°C for 16 hours. After cooling, the substrate was taken out and repeatedly rinsed with deionized water to obtain a conductive film substrate with a pink-purple CoP precursor grown thereon.

[0073] (4) The conductive film substrate on which the pink-purple CoP precursor was grown was freeze-dried and placed downstream of the magnetic boat. 0.45 g of sodium hypophosphite was placed upstream of the magnetic boat and placed in a tubular furnace. The temperature was raised to 300 °C at a heating rate of 5 °C / min under a nitrogen atmosphere and kept warm for phosphating for 1 h (the surface of the conductive film substrate changed from pink-purple to black, and the precursor on the surface of the conductive film substrate was converted to CoP). The membrane was cooled to room temperature, washed with deionized water, and freeze-dried to obtain an electrically controlled separation membrane (i.e., CoP / SSM) with a pore size of approximately 6.96 μm.

[0074] Comparative Example 1

[0075] Preparation of electronically controlled separation membrane:

[0076] (1) A stainless steel mesh (SSM) with an aperture of 800 mesh was selected as the conductive membrane substrate (size 5 cm × 5 cm). The conductive membrane substrate was first washed with 3M HCl, then with anhydrous ethanol, and finally with ultrapure water, and placed in an oven to dry for use.

[0077] (2) 8 mmol of cobalt nitrate hexahydrate was dissolved in 80 mL of water and magnetically stirred for 1 h (at a stirring speed of 800 r / min) until the mixture was uniformly mixed to obtain a cobalt nitrate solution.

[0078] (3) The conductive film substrate dried in step (1) was placed in the cobalt nitrate solution prepared in step (2), sealed together in a polyethylene autoclave, and hydroheated at 110° C. for 16 h. After cooling, the solution was found to be turbid. After being taken out, it was repeatedly rinsed with deionized water. No growth material was found on the stainless steel mesh of the obtained product.

[0079] Comparative Example 2

[0080] Preparation of electronically controlled separation membrane:

[0081] (1) A stainless steel mesh (SSM) with an aperture of 800 mesh was selected as the conductive membrane substrate (size 5 cm × 5 cm). The conductive membrane substrate was first washed with 3M HCl, then with anhydrous ethanol, and finally with ultrapure water, and placed in an oven to dry for use.

[0082] (2) 8 mmol of cobalt nitrate hexahydrate and 40 mmol of urea were dissolved in 80 mL of water and magnetically stirred for 1 h (at a stirring speed of 800 r / min) until the mixture was uniformly mixed to obtain a mixed solution.

[0083] (3) The conductive film substrate dried in step (1) was placed in the mixed solution prepared in step (2), sealed together in a polyethylene autoclave, and hydroheated at 110°C for 16 hours. After cooling, the solution was found to be turbid. After taking it out, it was repeatedly rinsed with deionized water. The material grown on the stainless steel mesh of the obtained product was randomly divided into blocks.

[0084] Effect Example 1

[0085] The scanning electron microscope image of the electrically controlled separation membrane (i.e. CoP / SSM) prepared in Example 1 is shown in FIG. Figure 1 .

[0086] The EDS diagram of the electrically controlled separation membrane (i.e. CoP / SSM) prepared in Example 1 is shown in FIG. Figure 2 .

[0087] from Figure 1 It can be seen that the CoP / SSM surface presents a uniformly distributed nanoarray structure, and the nanoarray reduces the membrane pore size.

[0088] from Figure 2 It can be seen that phosphorus and cobalt elements grow evenly on the SSM surface.

[0089] The XRD pattern of the electrically controlled separation membrane (i.e. CoP / SSM) prepared in Example 1 is shown in FIG. Figure 3 .

[0090] from Figure 3 It can be seen that the CoP / SSM prepared in Example 1 can observe obvious CoP crystal characteristic peaks.

[0091] Effect Example 2

[0092] The linear sweep voltammetry curves of the electrically controlled separation membrane (ie, CoP / SSM) and SSM prepared in Example 1 in 0.1 mol / L NaNO3 solution are shown in FIG. Figure 4 .

[0093] from Figure 4It can be seen that a reduction current appears in the LSV curve of CoP / SSM relative to SSM. This is because the nitrate is reduced on the surface of CoP / SSM, resulting in an increase in current density, indicating that the prepared electrode exhibits ideal electrochemical performance.

[0094] Effect Example 3

[0095] The electrically controlled separation membrane (ie, CoP / SSM) prepared in Example 1 was prepared into an electrochemical coupling system, and the pollutant removal effect was measured.

[0096] Electrochemical coupling system:

[0097] Assembly method: An electrically controlled separation membrane (prepared in Example) was placed between the water inlet and outlet troughs of the electrochemical coupling system reactor as a cathode, and the reactor was connected with silicone gaskets on both sides of the membrane and fixed with bolts. The water inlet and outlet troughs were both connected to peristaltic pumps for water inlet and outlet. An aluminum plate (6 cm × 6 cm) was used as an anode and was clamped in the card channel of the water inlet trough and placed parallel to the cathode. It was connected to a DC power supply and a constant voltage of 1.4 V was applied. The speed of the water inlet peristaltic pump was 20 r / min, and the speed of the water outlet peristaltic pump was 40 r / min. Water was pumped every 20 min in a constant flow discharge manner. It was used to treat wastewater containing 20 mg / L of humic acid (HA, 20 mg / L) and nitrate (sodium nitrate, 30 mg / L). The performance of the electrode material was tested in an electrochemical workstation (LSV curve test parameters: voltage start -1.2-0 V, scan rate 10 mV / S) and an electrochemical coupling system. Test parameters: The treated water was tested for humic acid content (wavelength 254nm) and nitrate content (wavelength 220nm) using an ultraviolet spectrophotometer.

[0098] The schematic diagram of the electrochemical coupling system is shown in Figure 5 .

[0099] Figure 6 shows the removal effect of nitrate in water contaminated with humic acid and nitrate by the electrically controlled separation membrane (i.e., CoP / SSM) prepared in Example 1 at different current densities.

[0100] The removal effect of the electrically controlled separation membrane (i.e. CoP / SSM) prepared in Example 1 on humic acid in water contaminated with humic acid and nitrate at different current densities is shown in the figure. Figure 7 .

[0101] The pollutant removal effects of the electrically controlled separation membranes (ie, CoP / SSM) prepared in Examples 1 to 4 are shown in Table 1.

[0102] Table 1 Performance results of the electrically controlled separation membranes prepared in Examples 1 to 4

[0103]

[0104] from Figure 6 It can be seen that the applied current density is 2.8~3.4A / m 2 When the nitrate removal rate reaches 74.5%, the membrane flux is 24L / (m 2 h)(5cm×5cm membrane constant flow water, every 20min pumping 20mL (0.02L), membrane flux = (10000 / 25)×3×0.02L / (m 2 ·h)), the energy consumption is 0.011Wh (1.4V×0.00788A×1h).

[0105] from Figure 7 It can be seen that the applied current density is 2.8~3.4A / m 2 When the humic acid is removed, the maximum removal rate can reach 96.2%.

[0106] Moreover, in a long-term test of 144 hours, it was found that applying a 2V voltage to the membrane for 10 minutes every 24 hours could remove all surface pollutants. The membrane flux of the electrically controlled separation membranes prepared in Examples 1 to 4 was restored to more than 95% of that before cleaning, and the nitrate removal rate was basically maintained at the optimal state.

[0107] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing an electrically controlled separation membrane, characterized in that: The following steps are involved: The conductive membrane substrate is placed in a mixed solution of a cobalt source, urea and ammonium fluoride, and after a hydrothermal reaction, a phosphating reaction is carried out together with a phosphorus source under an inert atmosphere to obtain the electrically controlled separation membrane.

2. The preparation method according to claim 1, characterized in that The molar ratio of the cobalt source, urea and ammonium fluoride is 2:(8-11):

5.

3. The preparation method according to claim 2, characterized in that The cobalt source includes cobalt nitrate.

4. The preparation method according to claim 1, characterized in that The temperature of the hydrothermal reaction is 110-120° C., and the time is 16-18 hours.

5. The preparation method according to claim 1, characterized in that The phosphating reaction temperature is 300-350°C and the time is 1-2 hours; And / or, the phosphorus source includes sodium hypophosphite.

6. The preparation method according to claim 1, characterized in that The pore size of the conductive film substrate is 400-800 meshes.

7. An electrically controlled separation membrane prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the electrically controlled separation membrane according to claim 7 in the construction of an electrochemical coupling system.

9. Use of the electrically controlled separation membrane according to claim 7 in the preparation of an electrochemical coupled reactor.

10. Use of the electrochemical coupling system according to claim 8 or the electrochemical coupling reactor according to claim 9 in the treatment of nitrate-complex contaminated water.

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