Electrodes, electrode units and electrolysis devices

Abstract

The application provides an electrode, an electrode unit and an electrolysis device. The electrode comprises a substrate and a catalyst layer, the catalyst layer is arranged on at least one surface of the substrate, and the catalyst layer comprises catalyst particles for catalyzing oxidation of ammonia nitrogen. A ratio of Dv50 of the catalyst particles to a thickness H1 of the single-sided catalyst layer satisfies 1≤Dv50 / H1≤4, and a number density of the catalyst particles per unit area on the surface of the catalyst layer is 1000 particles / cm 2 -10000 particles / cm 2 The electrode provided by the embodiments of the application can make the catalyst layer have a lower resistance, thereby helping to reduce the temperature of the electrode during electrolysis of waste liquid to reduce damage to the structure of the catalyst particles, so that the electrode can prolong the service life of the electrolysis device. Moreover, the contact area of the catalyst particles and the waste water can be increased, thereby helping the electrolysis device to treat high-concentration ammonia nitrogen waste liquid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste liquid treatment, and in particular to an electrode, an electrode unit and an electrolysis device. BACKGROUND

[0002] In the manufacturing process of some industrial products, a large amount of nitrogen-containing chemicals are used, so that a large amount of ammonia nitrogen is contained in the generated waste liquid. The ammonia nitrogen will consume a large amount of dissolved oxygen in water in the nitrification process, causing water quality deterioration. Therefore, the waste liquid containing ammonia nitrogen needs to be treated to reduce the ammonia nitrogen content in the waste liquid, so as to reach the standard for external discharge, thereby reducing the harm of the above waste liquid to the environment.

[0003] At present, the electrolysis device is mainly used to electrolyze and oxidize ammonia nitrogen in the waste liquid. However, in the related technology, the service life of the electrolysis device is short, and the ammonia nitrogen concentration treated is limited. SUMMARY

[0004] The present application provides an electrode, an electrode unit and an electrolysis device. The electrode not only can prolong the service life of the electrolysis device, but also helps the electrolysis device to treat high-concentration ammonia nitrogen waste liquid.

[0005] In a first aspect, the present application provides an electrode, comprising a substrate and a catalyst layer, the catalyst layer is arranged on at least one surface of the substrate, and the catalyst layer comprises catalyst particles for catalyzing oxidation of ammonia nitrogen, wherein the ratio of Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer satisfies 1≤Dv50 / H1≤4, and the number density of the catalyst particles per unit area on the surface of the catalyst layer is 1000 particles / cm 2 -10000 particles / cm 2 .

[0006] In the electrode provided by the present application, when the ratio of Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer satisfies the relationship of 1≤Dv50 / H1≤4, the catalyst layer has a low resistance, which helps to reduce the temperature of the electrode when electrolyzing the waste liquid to reduce the damage to the structure of the catalyst particles, so that the electrode can prolong the service life of the electrolysis device. Moreover, the contact area of the catalyst particles and the waste water can be increased, which helps the electrolysis device to treat high-concentration ammonia nitrogen waste liquid. When the number density of the catalyst particles per unit area on the surface of the catalyst layer is in the range of 1000 particles / cm 2 -10000 particles / cm 2 , the electrolysis device can further help to improve the treatment of high-concentration ammonia nitrogen waste liquid, so that the electrolyzed waste liquid reaches the standard for external discharge, thereby reducing the harm to the environment.

[0007] According to any of the preceding embodiments of the first aspect of the application, the ratio of the Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer satisfies: 1.5≤Dv50 / H1≤3.

[0008] According to any of the preceding embodiments of the first aspect of the application, the ratio of the Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer satisfies: 2≤Dv50 / H1≤2.5.

[0009] According to any of the preceding embodiments of the first aspect of the application, the number density of the catalyst particles per unit area of the catalyst layer surface is 3000 pieces / cm2 in at least one 10 μm*10 μm range of the catalyst layer. 2 - 8000 pieces / cm2 2 .

[0010] According to any of the preceding embodiments of the first aspect of the application, the number density of the catalyst particles per unit area of the catalyst layer surface is 5000 pieces / cm2 in at least one 10 μm*10 μm range of the catalyst layer. 2 - 6000 pieces / cm2 2 .

[0011] According to any of the preceding embodiments of the first aspect of the application, the Dv50 of the catalyst particles is 20 μm-40 μm.

[0012] According to any of the preceding embodiments of the first aspect of the application, the catalyst particles comprise a transition metal-based organic metal framework material.

[0013] According to any of the preceding embodiments of the first aspect of the application, the transition metal in the transition metal-based organic metal framework material comprises Fe and / or Mn.

[0014] According to any of the preceding embodiments of the first aspect of the application, the thickness H1 of the catalyst layer is 10 μm-20 μm.

[0015] According to any of the preceding embodiments of the first aspect of the application, the catalyst layer comprises a plurality of strip-shaped first catalyst layers, and the plurality of strip-shaped first catalyst layers are arranged at intervals along the width direction of the substrate.

[0016] In a second aspect, the embodiments of the present application provide an electrode unit, comprising a cathode and an anode, wherein the anode is the electrode in the first aspect of the present application.

[0017] In a third aspect, the embodiments of the present application provide an electrolytic device, comprising an electrolytic cell and an electrode unit, the electrode unit is arranged in the electrolytic cell, and the electrode unit is the electrode unit in the second aspect of the present application.

[0018] The above description is only a summary of the technical solutions of the present application. In order to make the technical means of the present application more clearly understood and implemented according to the content of the present application, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described below.

[0019] Drawings of the specification

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0021] Figure 1 A cross-sectional structure schematic diagram of an electrode provided by some embodiments of the present application is shown. DETAILED DESCRIPTION

[0022] The "range" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can include or not include the end value, and can be arbitrarily combined, i.e. any lower limit can be combined with any upper limit to form a range.

[0023] If not specifically stated, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0024] If not specifically stated, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0025] If not specifically stated, all steps of the present application can be performed in sequence or randomly, and the preferred method is to perform in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0026] If not specifically stated, the "comprising" and "including" mentioned in the present application represent open-ended, and can also be closed-ended. For example, the "comprising" and "including" can represent that other components not listed can also be included, or only the listed components can be included.

[0027] If not specifically stated, the term "or" in the present application is inclusive. For example, the phrase "A or B" represents "A, B, or both A and B". More specifically, any of the following conditions satisfy the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or A and B are both true (or exist).

[0028] Unless otherwise specified, the terms used in the present application have the commonly understood meanings understood by those skilled in the art.

[0029] Unless otherwise specified, the values of the parameters mentioned in the present application can be measured by various test methods commonly used in the art, for example, can be measured according to the test methods given in the embodiments of the present application.

[0030] In the present application, the ammonia-nitrogen waste liquid can use an electrolytic device, which generally includes an electrolytic tank and an electrode unit located in the electrolytic tank, wherein the electrode unit includes a cathode and an anode, and the cathode and the anode can separate the inside of the electrolytic tank into a cathode chamber and an anode chamber, and the cathode is located in the cathode chamber and the anode is located in the anode chamber. When the ammonia-nitrogen waste liquid is introduced into the electrolytic tank, the power supply is electrically connected to the cathode and the anode to form a loop, so that the anode can electrolyze to produce an oxidizing agent, which can oxidize ammonia-nitrogen to generate nitrogen, thereby reducing the ammonia-nitrogen in the waste liquid to meet the discharge standard.

[0031] However, in the related art, the electrolytic device has a fast temperature rise rate during electrolysis of the waste liquid, which can easily shorten the service life of the electrolytic device, especially when treating high-concentration ammonia-nitrogen waste liquid, the service life of the electrolytic device will be further shortened.

[0032] In view of this, the present application provides an electrode, an electrode unit and an electrolytic device, which not only prolongs the service life of the electrolytic device, but also helps the electrolytic device to treat high-concentration ammonia-nitrogen waste liquid.

[0033] Electrode

[0034] First aspect, please refer to Figure 1As shown, the electrode 10 provided by the embodiments of the present application comprises a substrate 100 and a catalyst layer 200, the catalyst layer 200 is arranged on at least one surface of the substrate 100, and the catalyst layer 200 comprises catalyst particles for catalyzing oxidation of ammonia nitrogen, wherein the ratio of Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer 200 satisfies 1≤Dv50 / H1≤4, and the number density of the catalyst particles per unit area on the surface of the catalyst layer 200 is 1000 particles / cm 2 -10000 particles / cm 2 .

[0035] In the embodiments of the present application, Dv50 refers to the particle size reaching 50% of the volume accumulation from the small particle size side in the particle size distribution on the volume basis, which can be tested by using a method or instrument well known in the art. For example, GB / T19077-2016 particle size distribution laser diffraction method can be referred to, and a laser particle size analyzer (for example, Master Size 3000) can be used for testing.

[0036] The thickness H1 of the single-sided catalyst layer 200 refers to the thickness of the catalyst layer 200 on one side of the substrate 100, which is measured by using a micrometer.

[0037] The number density of the catalyst particles per unit area on the surface of the catalyst layer 200 can be obtained by randomly selecting one or more regions with a length and a width distribution of 10 μm*10 μm under a SEM electron microscope, observing the regions, and counting the number of catalyst particles, and then comparing the total number of catalyst particles in the regions with the area of the regions.

[0038] In the electrode provided by the embodiments of the present application, when the ratio of Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer 200 satisfies the relationship of 1≤Dv50 / H1≤4, the catalyst layer 200 has a relatively low resistance, which is helpful to reduce the temperature of the electrode during electrolysis of waste liquid to reduce the damage to the structure of the catalyst particles, so that the electrode can prolong the service life of the electrolysis device. Moreover, the contact area of the catalyst particles and the waste water can be increased, which is helpful to the electrolysis device to treat high-concentration ammonia nitrogen waste liquid. Moreover, when the number density of the catalyst particles per unit area on the surface of the catalyst layer 200 is in the range of 1000 particles / cm 2 -10000 particles / cm 2 , the electrolysis device can further improve the treatment of high-concentration ammonia nitrogen waste liquid, so that the waste liquid after electrolysis meets the standard of external discharge, thereby reducing the harm to the environment.

[0039] In embodiments of the present application, the ammonia-nitrogen waste liquid refers to a waste liquid with an ammonia-nitrogen mass concentration greater than 500 mg / L, wherein the ammonia-nitrogen refers to combined nitrogen in the form of ammonia or ammonium ion, i.e., nitrogen in the form of free ammonia (NH3) and ammonium ion (NH4+) in the waste liquid. 4+ ) form in the waste liquid.

[0040] In embodiments of the present application, the ratio of the Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer 200 is within a suitable range, which can further help to reduce the temperature rise rate of the electrolysis device during electrolysis of the waste liquid and increase the contact area of the catalyst particles with the waste liquid, thereby prolonging the service life of the electrolysis device and increasing the concentration of ammonia-nitrogen in the treated waste liquid.

[0041] In some embodiments of the present application, the ratio of the Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer 200 satisfies: 1.5≤Dv50 / H1≤3.

[0042] In some other embodiments of the present application, the ratio of the Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer 200 satisfies: 2≤Dv50 / H1≤2.5.

[0043] For example, the ratio of the Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer 200 can be, but is not limited to, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, or a value range composed of any two of the above values. For example, the ratio of the Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer 200 can be, but is not limited to, 1.1-3.8, 1.5-3.2, 1.8-2.7.

[0044] In addition, in embodiments of the present application, the number density of the catalyst particles per unit area on the surface of the catalyst layer 200 is within a suitable range, which can further help to treat high-concentration ammonia-nitrogen waste liquid.

[0045] In some embodiments of the present application, the number density of the catalyst particles per unit area on the surface of the catalyst layer 200 is 3000-8000 particles / cm2 in at least one 10 μm*10 μm range of the catalyst layer 200. 2 -8000 particles / cm2. 2 .

[0046] In some embodiments of the present application, the number density of the catalyst particles per unit area on the surface of the catalyst layer 200 is 5000 particles / cm2 in at least one 10 μm*10 μm range of the catalyst layer 200.2 - 6000 particles / cm 2 .

[0047] Exemplarily, the number density of the catalyst particles per unit area of the surface of the catalyst layer 200 in at least one 10 pm*10 pm range of the catalyst layer 200 can be, but is not limited to, 1000 particles / cm 2 , 1100 particles / cm 2 , 1200 particles / cm 2 , 1300 particles / cm 2 , 1400 particles / cm 2 , 1500 particles / cm 2 , 1600 particles / cm 2 , 1700 particles / cm 2 , 1800 particles / cm 2 , 1900 particles / cm 2 , 2000 particles / cm 2 , 2100 particles / cm 2 , 2200 particles / cm 2 , 2300 particles / cm 2 , 2400 particles / cm 2 , 2500 particles / cm 2 , 2600 particles / cm 2 , 2700 particles / cm 2 , 2800 particles / cm 2 , 2900 particles / cm 2 , 3000 particles / cm 2 , 3100 particles / cm 2 , 3200 particles / cm 2 , 3300 particles / cm 2 , 3400 particles / cm 2 , 3500 particles / cm 2 , 3600 particles / cm 2 , 3700 particles / cm 2 , 3800 particles / cm 2 , 3900 particles / cm 2 , 4000 particles / cm 2 , 4100 particles / cm 2 , 4200 particles / cm 2 , 4300 particles / cm 2 , 4400 particles / cm 2 , 4500 particles / cm 2 , 4600 particles / cm 2 , 4700 particles / cm 2 , 4800 particles / cm 2 , 4900 particles / cm 2, 5000 particles / cm 2 , 5100 particles / cm 2 , 5200 particles / cm 2 , 5300 particles / cm 2 , 5400 particles / cm 2 , 5500 particles / cm 2 , 5600 particles / cm 2 , 5700 particles / cm 2 , 5800 particles / cm 2 , 5900 particles / cm 2 , 6000 particles / cm 2 , 7000 particles / cm 2 , 8000 particles / cm 2 , 9000 particles / cm 2 , 10000 particles / cm 2 , or a range between any two of the above values. For example, the number density of catalyst particles per unit area on the surface of the catalyst layer 200 can be, but is not limited to, 1100 particles / cm 2 -9000 particles / cm 2 , 1500 particles / cm 2 -8000 particles / cm 2 , 2000 particles / cm 2 -7000 particles / cm 2 , 2500 particles / cm 2 -6000 particles / cm 2 .

[0048] The Dv50 of the catalyst particles in a suitable range can help to thin the catalyst layer 200 while increasing the contact area between the catalyst particles and the waste liquid, thereby further reducing the temperature rise rate of the electrolytic device during electrolysis to extend its service life, and help to treat high-concentration ammonia-nitrogen waste liquid.

[0049] In some embodiments of the present application, the Dv50 of the catalyst particles is 20-40 μm. When the Dv50 of the catalyst particles is in the above range, it can help to reduce the thickness of the catalyst layer 200 and increase the contact area between the catalyst particles and the waste liquid, thereby extending the service life of the electrolytic device and helping the electrolytic device to treat high-concentration ammonia-nitrogen waste liquid.

[0050] For example, the Dv50 of the catalyst particles can be, but is not limited to, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, or a range between any two of the above values. For example, the Dv50 of the catalyst particles can be, but is not limited to, 21 μm-38 μm, 24 μm-36 μm, 25 μm-33 μm.

[0051] In embodiments of the present application, the electrocatalytic activity of the catalyst particles can further facilitate the treatment of the high-concentration ammonia-nitrogen waste liquid, and thus, the high-concentration ammonia-nitrogen waste liquid can be further treated by selecting a suitable catalyst particle material.

[0052] In some embodiments of the present application, the catalyst particles comprise a transition metal-based metal-organic framework material. The metal-organic framework material can improve the high porosity and high specific surface area, and thus, can further facilitate the treatment of the high-concentration ammonia-nitrogen waste liquid by the electrolysis device.

[0053] In some embodiments of the present application, the transition metal in the transition metal-based metal-organic framework material comprises Fe and / or Mn, which can enable the catalyst particles to have a high catalytic activity, and thus, facilitate the catalytic oxidation of ammonia-nitrogen in the waste liquid.

[0054] For example, the catalyst particles can comprise Fe-MOFs and Mn-MOFs, and both Fe-MOFs and Mn-MOFs can be purchased in the market.

[0055] In some embodiments of the present application, the catalyst particles have pores, and the porosity of the catalyst particles is 20%-50%. When the porosity of the catalyst particles is within the above range, the waste liquid can be infiltrated into the catalyst particles, and the contact probability between ammonia-nitrogen in the waste liquid and the active ingredients in the catalyst particles can be increased.

[0056] In embodiments of the present application, the porosity refers to the ratio of the volume of the pores to the total volume, and the volume % is used as the unit thereof. The measurement of the porosity is not particularly limited, and a method known in the art can be used. For example, the measurement of the porosity can be measured by using the Brunauer-Emmett-Teller (BET) measurement method of nitrogen, the water intrusion porosimeter method, the capillary flow porosimeter, or the mercury porosimeter (Hg porosimeter).

[0057] In some embodiments of the present application, the specific surface area of the catalyst particles can be 200 m 2 / g-5000 m 2 / g. When the specific surface area of the catalyst particles is set in the above range, the contact area of the catalyst particles with the waste liquid can be increased, thereby further facilitating the electrolytic device to treat the waste liquid with high concentration of ammonia nitrogen.

[0058] The specific surface area refers to the total area per unit mass of a substance, which can be measured by methods and instruments known in the art. For example, about 60 mg of a sample is weighed, dried at 100°C in vacuum for 14 hours, and the nitrogen adsorption amount is measured by using a gas adsorption method using nitrogen gas by using an automatic specific surface area measuring device (GEMINI VII manufactured by Shimadzu Corporation), and the BET specific surface area (m 2 / g).

[0059] In some embodiments of the present application, the thickness H1 of the catalyst layer 200 is 10 μm to 20 μm. When the thickness H1 of the catalyst layer 200 is in the above range, the temperature increase rate of the electrolytic device can be further reduced, thereby further improving the service life of the electrolytic device.

[0060] For example, the thickness H1 of the catalyst layer 200 can be, but is not limited to, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, or a range of values formed by any two of the above values. For example, the thickness H1 of the catalyst layer 200 can be, but is not limited to, 11 μm to 19 μm, 13 μm to 18 μm.

[0061] In some embodiments of the present application, the catalyst layer 200 includes a plurality of strip-shaped first catalyst layers, and the plurality of strip-shaped first catalyst layers are arranged at intervals in the width direction of the substrate 100. This can facilitate the discharge of nitrogen gas and the like generated by catalytically oxidizing ammonia nitrogen.

[0062] In some embodiments of the present application, the substrate 100 has a porous structure, such as a mesh material, a punched material, or a porous body. As a substrate having a porous structure, a metal fiber sintered body, a substrate with a large void ratio, and the like are also included. The substrate can include a metal such as titanium (Ti), nickel (Ni), iron (Fe), or an alloy (for example, SUS) including at least one of these metals.

[0063] Electrode unit

[0064] In a second aspect, embodiments of the present application provide an electrode unit including a cathode and an anode, wherein the anode is the electrode of the first aspect of the present application.

[0065] In the present application, the electrode unit can further include an electrolyte membrane, which is configured, for example, between the anode and the cathode.

[0066] The electrolyte membrane can be an electrolyte membrane having ion conductivity. The electrolyte membrane is not limited to a specific type. The electrolyte membrane can include an anion exchange membrane. The electrolyte membrane is configured in such a manner that oxygen generated at the anode and hydrogen generated at the cathode are not easily mixed.

[0067] Electrolytic device

[0068] In a third aspect, an embodiment of the present application provides an electrolytic device, including an electrolytic cell and an electrode unit, the electrode unit being disposed in the electrolytic cell, the electrode unit being the electrode unit of the second aspect of the present application.

[0069] In the present application, the electrolytic device can further include a voltage applier connected to the anode and the cathode to apply a voltage between the anode and the cathode.

[0070] By the voltage applier, the potential in the anode becomes high, and the potential in the cathode becomes low. The voltage applier can apply a voltage between the anode and the cathode, and is not limited to a specific type. The voltage applier can be a device that adjusts the voltage applied between the anode and the cathode. Specifically, when the voltage applier is connected to a direct current power source such as a storage battery, a solar cell, a fuel cell, or the like, the voltage applier has a DC / DC converter. When the voltage applier is connected to an alternating current power source such as a commercial power source, the voltage applier has an AC / DC converter. The voltage applier can be a power supply type power source that adjusts the voltage applied between the anode and the cathode and the current flowing between the anode and the cathode in such a manner that the electric power supplied to the water electrolytic device becomes a predetermined set value.

[0071] Embodiment

[0072] The embodiments described below are part of the embodiments of the present application, but not all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but only to represent specific embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without departing from the principles of the present application and without making creative efforts are within the scope of protection of the present application.

[0073] Embodiment 1

[0074] Fe-MOFs with a Dv50 of about 20 μm and a binder polyvinylidene fluoride were dispersed in a weight ratio of 98:2 into an N-methylpyrrolidone (NMP) solvent to obtain a catalyst layer slurry. The obtained slurry was coated on a titanium substrate, dried, and subjected to a heating and pressing process to obtain an anode having a catalyst layer thickness H1 of 20 μm, wherein the number density p of catalyst particles per unit area on the surface of the catalyst layer was 1500 particles / cm2. 2 .

[0075] Embodiment 2

[0076] This example differs from Example 1 in that the Dv50 of the Fe-MOFs is about 30 pm.

[0077] Example 3

[0078] This example differs from Example 1 in that the Dv50 of the Fe-MOFs is about 40 pm.

[0079] Example 4

[0080] This example differs from Example 3 in that the catalyst layer thickness H1 is about 10 pm.

[0081] Example 5

[0082] This example differs from Example 1 in that the number density p of catalyst particles per unit area on the surface of the catalyst layer is 5000 particles / cm2. 2 .

[0083] Example 6

[0084] This example differs from Example 1 in that the number density p of catalyst particles per unit area on the surface of the catalyst layer is 8000 particles / cm2. 2 .

[0085] Example 7

[0086] This example differs from Example 1 in that the number density p of catalyst particles per unit area on the surface of the catalyst layer is 10000 particles / cm2. 2 .

[0087] Example 8

[0088] This example differs from Example 1 in that the catalyst particles are Mn-MOFs.

[0089] Comparative Example 1

[0090] This comparative example differs from Example 1 in that the Dv50 / H1 is 0.5.

[0091] Comparative Example 2

[0092] This comparative example differs from Example 1 in that the Dv50 / H1 is 6.

[0093] Comparative Example 3

[0094] This comparative example differs from Example 1 in that the number density p of catalyst particles per unit area on the surface of the catalyst layer is 500 particles / cm2. 2 .

[0095] Comparative Example 4

[0096] The difference between this comparative example and Example 1 is that the number density of catalyst particles per unit area on the surface of the catalyst layer is 20,000 particles / cm 2 .

[0097] Application Examples 1-12

[0098] The electrodes in Examples 1-8 and Comparative Examples 1-4 were used as anodes of an electrolysis device, and formed into an electrode unit with a flat titanium plate (cathode). The spacing between the anode and cathode was 30 cm. The flow rate of the wastewater was controlled to be approximately 2 L / min, the current density was 5 A / dm2, the electrolysis voltage was 6 V, and the ammonia nitrogen mass concentration C1 in the wastewater was 800 mg / L. The experimental results of treating the wastewater using the electrolysis device are shown in Table 1.

[0099] Application Examples 13-15

[0100] The difference between Application Examples 13-15 and Application Example 1 is that C1 in Application Example 13 is 1000 mg / L, C1 in Application Example 14 is 1200 mg / L, and C1 in Application Example 15 is 1500 mg / L.

[0101] Test section

[0102] (1) Dv50 measurement

[0103] Refer to GB / T 19077-2016 particle size distribution laser diffraction method and use a laser particle size analyzer (such as MasterSize 3000) for testing

[0104] (2) H1 measurement

[0105] Measured using a micrometer.

[0106] (3)ρ test

[0107] Under the SEM electron microscope, randomly select one or more areas with a length and width distribution of 10μm*10μm, observe in this area, and count the number of catalyst particles. The total number of catalyst particles in the area can be compared with the area of ​​the area to obtain the above-mentioned number density.

[0108] (4) Resistance test

[0109] The Yuanneng Technology BER2500 device was used with a sampling time of 10 s.

[0110] The disassembled anode is cleaned with DMC for 2-3 times, and after cleaning, the anode is placed in a 65°C oven for drying for 60 min, and the dried anode is sampled (cut to 10 mm*10 mm) in a drying room to obtain a sample: the sample is tested using the Yuan Energy Technology BER2500 at a test temperature of about 25°C, a humidity of ≤40% RH, and a test pressure of 0.7 Mpa, and the test result resistance is recorded.

[0111] (5) Service life test

[0112] The ammonia-nitrogen wastewater is electrolyzed using the electrolytic device described above until the anode is damaged, and the working time of the anode is recorded, which is the service life.

[0113] (6) Ammonia-nitrogen removal rate test

[0114] The ammonia-nitrogen mass concentration in the waste liquid is measured using an ammonia-nitrogen detector, i.e., the ammonia-nitrogen mass concentration C1 before electrolysis and the ammonia-nitrogen mass concentration C2 after electrolysis, and then the ammonia-nitrogen removal rate (%) = (C1-C2) / C1*100%.

[0115] Table 1

[0116]

[0117] According to Table 1, comparing the experimental data of Application Examples 1-8, 13-15 and Application Examples 9-12, it can be seen that in the electrode provided in the present application, when the ratio of Dv50 of the catalyst particles to the thickness H1 of the single-sided catalyst layer satisfies the relationship 1≤Dv50 / H1≤4, the catalyst layer has a relatively low resistance, which in turn helps to reduce the temperature of the electrode during electrolysis of the waste liquid to reduce the damage to the structure of the catalyst particles, thereby enabling the electrode to prolong the service life of the electrolytic device. Moreover, it can also increase the contact area of the catalyst particles with the wastewater, thereby helping the electrolytic device to treat high-concentration ammonia-nitrogen wastewater. And when the number density of the catalyst particles per unit area on the surface of the catalyst layer is in the range of 1000 particles / cm 2 -10000 particles / cm 2 , it can further help to improve the electrolytic device to treat high-concentration ammonia-nitrogen wastewater.

[0118] Finally, it should be noted that: the above experimental examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing experimental examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing experimental examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the experimental examples of the present application.

Claims

1. An electrode, characterized in that include: substrate; as well as, A catalyst layer is provided on at least one surface of the substrate, the catalyst layer comprising catalyst particles for catalytic oxidation of ammonia nitrogen, wherein the ratio of Dv50 of the catalyst particles to the thickness H1 of the catalyst layer on one side satisfies: 1≤Dv50 / H1≤4, and the number density of the catalyst particles per unit area on the surface of the catalyst layer is 1000 particles / cm 2 -10,000 particles / cm 2 ; The catalyst particles include a transition metal-based organic metal framework material, the transition metal in the transition metal-based organic metal framework material includes Fe and / or Mn, and the thickness H1 of the catalyst layer is 10 μm-20 μm.

2. The electrode according to claim 1, characterized in that The ratio of Dv50 of the catalyst particles to the thickness H1 of the catalyst layer on one side satisfies: 1.5≤Dv50 / H1≤3.

3. The electrode according to claim 2, characterized in that The ratio of Dv50 of the catalyst particles to the thickness H1 of the catalyst layer on one side satisfies: 2≤Dv50 / H1≤2.

5.

4. The electrode according to claim 1 or 2, characterized in that In at least one 10 μm*10 μm area of ​​the catalyst layer, the number density of the catalyst particles per unit area on the surface of the catalyst layer is 3000 particles / cm 2 -8000 particles / cm 2 .

5. The electrode according to claim 4, characterized in that In at least one 10 μm*10 μm area of ​​the catalyst layer, the number density of the catalyst particles per unit area on the surface of the catalyst layer is 5000 particles / cm 2 -6000 particles / cm 2 .

6. The electrode according to claim 1, characterized in that The Dv50 of the catalyst particles is 20 μm-40 μm.

7. The electrode according to claim 1, characterized in that The catalyst layer includes a plurality of strip-shaped first catalyst layers, and the plurality of strip-shaped first catalyst layers are arranged at intervals along the width direction of the substrate.

8. An electrode unit, characterized in that: include: cathode; as well as, The anode is the electrode according to any one of claims 1 to 7.

9. An electrolysis device, characterized in that: include: electrolytic cell; as well as, An electrode unit is provided in the electrolytic cell, and the electrode unit is the electrode unit described in claim 8.

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