Wastewater COD (Chemical Oxygen Demand) degradation coupling hydrogen production catalyst, preparation method, system and method

Abstract

The invention belongs to the technical field of wastewater treatment, and particularly relates to a wastewater COD degradation coupling hydrogen production catalyst, a preparation method, a system and a method. Compared with the prior art, the COD degradation hydrogen production reactor is matched with the wastewater COD degradation coupling hydrogen production catalyst, deep oxidation treatment of high-COD water quality is achieved, continuous operation can be achieved through the constructed wastewater COD degradation coupling hydrogen production system, and therefore the water quality with low organic pollutants is obtained. The electrochemical oxidation method is used for COD degradation, COD in water is efficiently and accurately degraded by controlling parameters such as current, voltage and time, conversion of organic pollutants in wastewater is completed, and the method has the advantages of being short in technological process, remarkable in COD reduction effect, environmentally friendly, low in carbon, continuous, reliable and the like. The byproduct hydrogen generated by wastewater COD degradation has a wide application range, can be used for fuel cell power generation, realizes wastewater COD degradation driven by green electricity, and realizes long-period green low-carbon operation.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a wastewater COD degradation coupled hydrogen production catalyst, a preparation method, a system and a method. Background Art

[0002] Chemical oxygen demand (COD) is a measurement method that uses chemical methods to test substances that need to be oxidized in water. It can characterize the content of pollutants in polluted water sources. It is regarded as an important and rapid parameter for determining the content of organic pollutants in many industries such as petroleum, chemical industry, and sewage treatment. It is often represented by the symbol COD. Excessive COD content in water will destroy the original living environment of various organisms in the water body, and will also emit irritating odors, causing adverse effects on surrounding residents and the environment. Therefore, the state has issued emission standards for COD water quality, and each industry must reduce the COD content in the water according to the corresponding indicators to meet the external discharge requirements.

[0003] Traditionally, chemical methods and microbial degradation methods are mainly used to treat high COD wastewater. The chemical method is to add strong oxidants to the wastewater to oxidize the high COD wastewater. Commonly used oxidants include potassium permanganate, ozone and chlorine. These oxidants can oxidize organic matter into inorganic matter or lower molecular weight organic matter, thereby achieving the purpose of reducing COD. However, it is difficult to control the amount of oxidant added during the treatment process, which can easily cause secondary pollution. The microbial degradation method uses activated sludge containing microorganisms to treat wastewater and oxidize organic matter in the water, thereby achieving the purpose of reducing the COD content in the wastewater. However, the microorganisms in this microbial degradation method are easily affected by external environmental factors such as temperature and pH value, resulting in limited microbial ability to treat organic matter; in addition, in the process of batch reduction of COD, the use of microbial treatment methods requires precise control of various operating parameters, which greatly increases the complexity of actual operation and management.

[0004] It can be seen that in response to the existing COD degradation problem, proposing a wastewater COD degradation coupled hydrogen production system and method is an important issue that needs to be urgently solved in this field. Summary of the invention

[0005] In order to solve the various drawbacks existing in the existing COD degradation technology, the purpose of the present invention is to provide a wastewater COD degradation coupled hydrogen production catalyst, preparation method, system and method, which at least partially solve the problems existing in the prior art. In order to achieve the purpose of the above invention, the present invention provides the following technical solutions.

[0006] The present invention provides a catalyst for wastewater COD degradation coupled with hydrogen production, which is an impregnated nickel-iron oxide, a nickel-based metal nanosheet loaded with nickel / iron active components, the nanosheet thickness is 2 to 10 nm, and the loading amount of the nickel / iron active components is 3 to 5 mg / cm 2 .

[0007] The present invention also provides a method for preparing the catalyst, comprising the following steps:

[0008] (1) removing surface impurities and oxides from a nickel-based metal carrier and drying the carrier at 40 to 100° C. for 12 to 24 hours;

[0009] (2) preparing an active metal soluble salt solution, impregnating the nickel-based metal support by supersaturated impregnation for 6 to 12 hours, and then drying at 40 to 100° C. for 6 to 24 hours;

[0010] The molar ratio of nickel to iron in the active metal soluble salt solution is (3-5):1.

[0011] In some embodiments, the nickel-based metal carrier in the preparation method of the present invention is nickel foam, nickel mesh, nickel felt, or nickel powder felt.

[0012] In some embodiments, in the preparation method of the present invention, the method for removing surface impurities and oxides is to soak in water, acetone, and ethanol solutions for 2 to 4 hours in sequence. First, soak in water for 2 to 4 hours, then soak in acetone for 2 to 4 hours to remove oil stains, and then soak in ethanol for 2 to 4 hours to remove residual acetone on the surface.

[0013] In some embodiments, in the preparation method of the present invention, the soluble salt of the active metal is one or more of nickel nitrate, nickel chloride, ferric sulfate, and ferric nitrate.

[0014] In some embodiments, in the preparation method of the present invention, the dissolution medium of the active metal soluble salt is one or more of water, ethanol, and isopropanol.

[0015] Furthermore, the present invention also provides a wastewater COD degradation coupled hydrogen production system, which is composed of a hydrogen production reaction system and a COD degradation reaction system;

[0016] The hydrogen production reaction system comprises a cathode wastewater replenishing device, a cathode wastewater storage device, a cathode centrifugal pump and a COD degradation hydrogen production reactor connected by pipelines; the COD degradation reaction system comprises an anode wastewater replenishing device, an anode wastewater storage device, an anode centrifugal pump and a COD degradation hydrogen production reactor connected by pipelines;

[0017] The COD degradation hydrogen production reactor in the hydrogen production reaction system and the COD degradation hydrogen production reactor in the COD degradation reaction system are the same device, which is an electrolytic reactor with symmetrically placed metal plates. The reactor is provided with the above-mentioned wastewater COD degradation coupled hydrogen production catalyst, and a wastewater circulation pipe is provided in the middle of the metal plate; the COD degradation hydrogen production reactor is connected to a DC power supply.

[0018] In the COD degradation hydrogen production reactor of the present invention, wastewater enters the reactor from both sides through the cathode centrifugal pump and the anode centrifugal pump respectively, and flows from bottom to top. The reactor completes COD degradation and hydrogen production reaction under the action of a DC power supply, and the COD of the wastewater at the anode outlet can be reduced by 80%.

[0019] Furthermore, the cathode centrifugal pump and the anode centrifugal pump in the wastewater COD degradation coupled hydrogen production system described in the present invention are centrifugal pumps that are resistant to acid, alkali and chloride ion corrosion, which can ensure that the waste liquid from the cathode wastewater storage tank and the anode wastewater storage tank is continuously transported to the COD degradation hydrogen production reactor over a long period of time.

[0020] Furthermore, in some embodiments, the wastewater COD degradation coupled hydrogen production system also includes a wastewater heating device, a post-reaction wastewater reflux pipeline and / or a produced gas output pipeline.

[0021] In some specific embodiments, the post-reaction wastewater flows back from the COD degradation hydrogen production reactor to the cathode wastewater storage device and the anode wastewater storage device through a reflux pipeline.

[0022] In some specific embodiments, the gas generated after the reaction is refluxed from the COD degradation hydrogen production reactor to the cathode wastewater storage device and the anode wastewater storage device through a reflux pipeline together with the wastewater after the reaction. Further, the output gas output pipelines of the cathode wastewater storage device and the anode wastewater storage device are used for subsequent treatment.

[0023] In some embodiments, the wastewater COD degradation coupled hydrogen production system further includes a control system, and the power supplies of all devices are connected to the control system, which can be centrally controlled and monitored in real time.

[0024] Furthermore, the present invention also provides a method for wastewater COD degradation coupled with hydrogen production,

[0025] The wastewater in the cathode wastewater replenishing device and the anode wastewater replenishing device flows into the cathode wastewater storage device and the anode wastewater storage device through pipelines;

[0026] The wastewater from the cathode wastewater storage device and the anode wastewater storage device flows out through pipelines and enters the cathode centrifugal pump and the anode centrifugal pump respectively. The wastewater is transported to the COD degradation hydrogen production reactor through the cathode centrifugal pump and the anode centrifugal pump respectively.

[0027] Under the action of DC power supply, the cathode side of COD degradation hydrogen production reactor produces hydrogen, and the anode side completes the oxidation of organic matter to reduce COD.

[0028] The wastewater after the reaction is completed is circulated back to the cathode wastewater storage tank and the anode wastewater storage tank through pipelines for recycling.

[0029] Furthermore, in some embodiments, a wastewater heating device is provided in the cathode wastewater replenishment device and the anode wastewater replenishment device for heating and keeping the wastewater warm; a wastewater heating device is provided in the cathode wastewater storage device and the anode wastewater storage device for heating and keeping the wastewater warm.

[0030] In some embodiments, the heating and insulation temperature is 40-90°C.

[0031] In some embodiments, the wastewater COD degradation coupled hydrogen production method further includes the steps of post-treating the hydrogen produced on the cathode side of the COD degradation hydrogen production reactor and post-treating the gas produced on the anode side of the COD degradation hydrogen production reactor.

[0032] In some specific embodiments, the hydrogen produced on the cathode side is transported to a subsequent gas separation unit through a pipeline for purification to obtain pure hydrogen. In some embodiments, the purity of the purified hydrogen of the present invention can reach 99.99%, and can be directly introduced into a fuel cell to generate electricity, and the generated electricity can be used in a COD degradation hydrogen production reactor.

[0033] The electricity used by the DC power supply of the present invention may come from one or more of industrial electricity and renewable energy power generation.

[0034] In some embodiments, the electricity used by the DC power supply of the present invention comes from wind power generation or solar power generation.

[0035] In some embodiments, the electricity used by the DC power supply of the present invention comes from the purified hydrogen used to generate electricity in a fuel cell.

[0036] In some specific embodiments, the carbon dioxide or other gases produced on the anode side can be directly discharged from the top of the anode wastewater storage tank. In some specific embodiments, the carbon dioxide or carbon-based components produced on the anode side can be absorbed in water to form carbonate ions.

[0037] In some embodiments, the wastewater in the wastewater COD degradation coupled hydrogen production method is selected from one or more of oilfield produced water, chemical wastewater, and urban water.

[0038] In some embodiments, the flow rate of the cathode centrifugal pump and the anode centrifugal pump in the wastewater COD degradation coupled hydrogen production method is 0.1 to 2 L / min.

[0039] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0040] (1) The present invention adopts a COD degradation hydrogen production reactor in combination with a wastewater COD degradation coupled hydrogen production catalyst to achieve deep oxidation treatment of high COD water quality. The constructed wastewater COD degradation coupled hydrogen production system can achieve continuous operation, thereby obtaining low organic pollutant water quality.

[0041] (2) The present invention innovatively adopts electrochemical oxidation method for COD degradation. It does not need to add oxidants to the water sample, will not introduce other chemical substances, and has no secondary pollution. By controlling parameters such as current, voltage, and time, COD in the water can be efficiently and accurately degraded to complete the transformation of organic pollutants in the wastewater. Most of the organic matter can finally be electrochemically burned into carbon dioxide and water, and a small part of large molecular organic matter that is difficult to degrade can be degraded into small molecular substances. At the same time, it has the functions of flotation, flocculation, and sterilization. Compared with the existing microbial degradation process, it has the advantages of short process flow, significant COD reduction effect, green and low-carbon, continuous and reliable.

[0042] (3) The by-product hydrogen generated by the COD degradation of wastewater described in the present invention has a wide range of uses and can be used for fuel cell power generation to supply the system described in the present invention, so that green electricity can drive the COD degradation of wastewater, realize long-term green and low-carbon operation, and help achieve the country's "dual carbon" strategic goals. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0044] Figure 1 Electron micrograph of the catalyst prepared in Example 1. DETAILED DESCRIPTION

[0045] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict; and all other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments in this disclosure are within the scope of protection of this disclosure.

[0046] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein may be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein may be implemented independently of any other aspect, and two or more of these aspects may be combined in various ways. For example, any number of aspects described herein may be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein may be used to implement this device and / or practice this method.

[0047] The system and method for wastewater COD degradation coupled with hydrogen production described in the present invention are described as follows: wastewater with high COD content such as oilfield produced water, chemical wastewater, and urban reclaimed water is input into a cathode wastewater replenishing device and an anode wastewater replenishing tank device respectively after natural sedimentation and impurity removal for preheating of the wastewater, and the heating temperature is 40-90°C; after reaching the preset temperature, the wastewater inside the cathode wastewater replenishing device and the anode wastewater replenishing device flows into the cathode wastewater storage device and the anode wastewater storage device respectively, and a heating device is provided in the wastewater storage device to perform secondary heating and heat preservation on the wastewater; then the wastewater flows out from the cathode wastewater storage device and the anode wastewater storage device and enters the cathode centrifugal pump and the anode centrifugal pump respectively, and the wastewater is transported to the COD degradation hydrogen production reactor through a water pump, wherein The flow rate of the middle pump is 0.1-2L / min; the wastewater contacts with the special catalyst for COD degradation and reacts under the action of the DC power supply, wherein the COD degradation hydrogen production reactor is all made of high-purity corrosion-resistant titanium material, and an oxidation reaction occurs near the anode metal plate to complete the oxidation of organic matter to reduce COD, while a reduction reaction is completed near the cathode metal plate to produce hydrogen; the wastewater after the reaction is entrained with gas is circulated back to the cathode wastewater storage device and the anode wastewater storage device for gas-liquid separation, and the hydrogen produced on the cathode side is transported from the top of the cathode wastewater storage device to the subsequent gas separation unit for purification to obtain pure hydrogen, and the carbon dioxide and other gases or carbon-based components produced on the anode side can be absorbed in the water to form carbonate ions, and finally the water quality of COD degradation is obtained.

[0048] Example 1: Catalyst for coupled hydrogen production by wastewater COD degradation

[0049] The nickel-based metal carrier nickel foam (10×10cm) to be treated is placed in about 100ml of water, acetone, and ethanol solution and soaked for 3 hours, and then the soaked nickel foam is transferred to a 70°C oven for drying for 24 hours. Weigh 28.3g of nickel nitrate and disperse it in about 300ml of deionized water to obtain green solution A, weigh 10.4g of ferric sulfate solvent in 400ml of deionized water to obtain solution B, slowly pour solution A into solution B to prepare immersion solution C, and immerse the above-treated nickel foam in solution C for 8 hours. After the immersion is completed, take out the nickel foam and place it in a 70°C oven for drying for 24 hours to obtain a nickel-iron oxide catalyst specifically for sewage COD degradation. Figure 1 The catalyst is in the form of nanosheets, with an average thickness of about 3.5 nm and a catalyst loading of 3.6 mg / cm 2 When the immersion time in mixed solution C was changed to 6 hours, the average thickness of the nanosheets was about 2.9 nm and the catalyst loading was 2.7 mg / cm 2 The immersion time was changed to 12 hours, at which time the average thickness of the nanosheets was about 3.6 nm and the catalyst loading was 3.4 mg / cm 2 .

[0050] Example 2: Catalyst for coupled hydrogen production by wastewater COD degradation

[0051] The nickel-based metal carrier nickel foam (10×10cm) to be treated is placed in about 100ml of water, acetone, and ethanol solution for 3 hours, and then the soaked nickel foam is transferred to a 70°C oven for drying for 24 hours. Weigh 36.1g of nickel nitrate and disperse it in about 300ml of deionized water to obtain green solution A, weigh 10.4g of ferric sulfate solvent in 400ml of deionized water to obtain solution B, slowly pour solution A into solution B to prepare immersion solution C, at which the nickel-iron molar ratio is 4:1, and the treated nickel foam is placed in solution C for 8 hours. After the immersion is completed, the nickel foam is taken out and placed in a 70°C oven for drying for 24 hours to obtain a nickel-iron oxide catalyst for sewage COD degradation. At this time, the prepared catalyst is in the form of nanosheets, with an average thickness of about 2.9nm and a catalyst loading of 2.9mg / cm 2 The above 36.1g nickel nitrate was changed to 41.2g nickel nitrate and dispersed in about 300ml of deionized water to make a mixed impregnation solution C. At this time, the molar ratio of nickel to iron was 5:1. From the electron microscope image, it can be seen that the average thickness of the nanosheets is about 2.5nm, and the catalyst loading is 2.6mg / cm 2 .

[0052] Example 3: Catalyst for coupled hydrogen production by wastewater COD degradation

[0053] The nickel-based metal carrier nickel foam (10×10 cm) to be treated was treated in a similar manner to Example 1, and was placed in about 100 ml of water, acetone, and ethanol solution for 3 hours, respectively, and then the soaked nickel foam was transferred to a 70°C oven for drying for 24 hours. Weigh 28.3 g of nickel nitrate and disperse it in about 300 ml of isopropanol to obtain a green solution A, weigh 10.4 g of ferric sulfate solvent in 400 ml of isopropanol to obtain a solution B, slowly pour solution A into solution B to prepare an impregnation solution C, and place the treated nickel foam in solution C for 8 hours. After the impregnation is completed, take out the nickel foam and place it in a 70°C oven for drying for 24 hours. Scanning electron microscopy shows that the prepared catalyst is in the form of thin nanosheets, with an average thickness of about 1.2 nm and a catalyst loading of 1.6 mg / cm 2 , the catalyst loading is low, and the growth of nanosheet structure is unfavorable. After the solvent is replaced with ethanol, the prepared catalyst is in the form of uneven nanosheets, with an average thickness of about 0.7nm and a catalyst loading of 0.6mg / cm 2 , the catalyst loading is lower.

[0054] Example 4: Catalyst for coupled hydrogen production by wastewater COD degradation

[0055] The nickel-based metal carrier nickel mesh (10×10 cm) to be treated was treated in a similar manner to Example 1, and was placed in about 100 ml of water, acetone, and ethanol solution for 3 hours, respectively, and then the soaked nickel mesh was transferred to a 70°C oven for drying for 24 hours. Weigh 28.3 g of nickel nitrate and disperse it in about 300 ml of deionized water to obtain a green solution A, weigh 10.4 g of ferric sulfate solvent in 400 ml of deionized water to obtain a solution B, slowly pour solution A into solution B to prepare an immersion solution C, and immerse the treated nickel foam in solution C for 8 hours. After the immersion is completed, take out the nickel foam and place it in a 70°C oven for drying for 24 hours. At this time, the prepared catalyst has no nanostructure, and the catalyst loading is only 0.3 mg / cm 2 , the nanosheet structure is not easy to grow on the surface of the nickel mesh. After the nickel-based metal carrier was replaced with rough nickel felt and nickel powder felt, the prepared catalyst began to have nanosheets, with an average thickness of about 1.1nm (nickel felt) and 1.3nm (nickel powder felt), and the catalyst loading was 0.5mg / cm 2 (Nickel felt), 0.6mg / cm 2 (Nickel powder felt).

[0056] Test example:

[0057] According to the method for degrading COD content in wastewater of the present invention, the catalyst described in Example 1 is used, the water quality conditions are referred to, and the reaction conditions are referred to Table 1 and Table 2. The details of the wastewater COD degradation coupled hydrogen production experiment are as follows:

[0058] The catalyst prepared in Example 1 was loaded into the COD degradation hydrogen production reactor, the pipelines and circuits were connected, the oil field produced water was introduced into the device, and relevant experiments were carried out according to the relevant experimental operating parameters in Table 2.

[0059] Table 1 Main properties of COD wastewater from different sources

[0060] Oilfield produced water Chemical wastewater Urban water pH 7.6 1.2 7.3 Oil content (mg / L) 115.2 23.3 15.4 Turbidity (NTU) 350 134 258.7 Suspended matter (mg / L) 1800 1240 1520 COD(mg / L) 16000 12000 1350

[0061] Table 2 Test conditions

[0062]

[0063] The wastewater COD degradation catalyst was prepared by the same catalyst preparation method as in Example 1. The prepared catalyst was loaded into the COD degradation hydrogen production reactor, the pipelines and circuits were connected, the chemical wastewater was introduced into the device, and the relevant experiments were carried out according to the relevant experimental operation parameters in Table 2.

[0064] The sewage COD degradation catalyst was prepared by the same catalyst preparation method as in Example 1. The prepared catalyst was loaded into the COD degradation hydrogen production reactor, the pipelines and circuits were connected, the city water was introduced into the device, and the relevant experiments were carried out according to the relevant experimental operation parameters in Table 2.

[0065] Table 3 Reaction results of COD treatment devices for water degradation from different sources

[0066] Oilfield produced water Chemical wastewater Urban water pH 9.6 9.1 9.5 Oil content (mg / L) 8.2 7.3 4.4 Turbidity (NTU) 140 65 106 Suspended matter (mg / L) 254 231 218 COD(mg / L) 2832 2160 270

[0067] It can be seen from the results in Table 3 that wastewater with high COD content from different sources is treated according to the wastewater COD degradation coupled hydrogen production device adopted by the present invention. The COD degradation rate of the wastewater COD degradation catalyst exceeds 80% within 6 hours. At the same time, the oil content, turbidity, suspended matter and other indicators in the water are reduced by more than 50%. The portable hydrogen purity analyzer detects that the purity of hydrogen production can reach 99.99%, which realizes the efficient conversion of organic pollutants in the wastewater. At the same time, high-purity hydrogen can be produced as a by-product, which satisfies the simultaneous acquisition of wastewater treatment and high value-added products.

[0068] According to the above method, the sewage COD degradation catalysts prepared in Examples 2-4 were used to treat wastewater with high COD content from different sources using the wastewater COD degradation coupled hydrogen production device adopted by the present invention. The results showed that the COD degradation rate exceeded 80% within 6 hours, and at the same time, indicators such as oil content, turbidity, and suspended matter in the water were reduced by more than 50%. The portable hydrogen purity analyzer detected that the hydrogen production purity can reach 99.99%.

[0069] In the above examples, the reliability of the long-term operation of the prepared sewage COD degradation catalyst and its system was verified, and its universality was proved in the treatment of different water qualities, showing excellent COD degradation performance. Therefore, the wastewater COD degradation coupled hydrogen production system and method described in the present invention has the advantages of short process flow, significant COD reduction effect, green and low-carbon, continuous and reliable, etc., which can meet the degradation treatment requirements of COD of water quality from different sources, and produce high-purity hydrogen as a by-product, which can realize the resource utilization of wastewater and help achieve the national "dual carbon" strategic goals.

[0070] For ordinary technicians in this field, the specific embodiments are only illustrative descriptions of the present invention. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concepts and technical solutions of the present invention, or the concepts and technical solutions of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A catalyst for wastewater COD degradation coupled with hydrogen production, characterized in that: The nickel-based metal nanosheet is loaded with nickel / iron active components, the thickness of the nanosheet is 2 to 10 nm, and the loading amount of the nickel / iron active components is 3 to 5 mg / cm 2 .

2. The method for preparing the catalyst according to claim 1, characterized in that: The following steps are involved: (1) removing surface impurities and oxides from a nickel-based metal carrier and drying the carrier at 40 to 100° C. for 12 to 24 hours; (2) preparing an active metal soluble salt solution, impregnating the nickel-based metal support by supersaturated impregnation for 6 to 12 hours, and then drying at 40 to 100° C. for 6 to 24 hours; The molar ratio of nickel to iron in the active metal soluble salt solution is (3-5):

1.

3. The preparation method according to claim 2, characterized in that: The nickel-based metal carrier is nickel foam, nickel mesh, nickel felt or nickel powder felt; the method for removing surface impurities and oxides is soaking in water, acetone and ethanol solutions for 2 to 4 hours in sequence; the active metal soluble salt is one or more of nickel nitrate, nickel chloride, ferric sulfate and ferric nitrate; the dissolving medium of the active metal soluble salt is one or more of water, ethanol and isopropanol.

4. A wastewater COD degradation coupled hydrogen production system, characterized in that: It consists of a hydrogen production reaction system and a COD degradation reaction system; The hydrogen production reaction system comprises a cathode wastewater replenishing device, a cathode wastewater storage device, a cathode centrifugal pump and a COD degradation hydrogen production reactor connected by pipelines; the COD degradation reaction system comprises an anode wastewater replenishing device, an anode wastewater storage device, an anode centrifugal pump and a COD degradation hydrogen production reactor connected by pipelines; The COD degradation hydrogen production reactor in the hydrogen production reaction system and the COD degradation hydrogen production reactor in the COD degradation reaction system are the same device, which is an electrolytic reactor with symmetrically placed metal plates. The COD degradation hydrogen production reactor is provided with the catalyst for wastewater COD degradation coupled hydrogen production as claimed in claim 1, and a wastewater circulation pipe is provided in the middle of the metal plate; the COD degradation hydrogen production reactor is connected to a DC power supply.

5. The wastewater COD degradation coupled hydrogen production system according to claim 4, characterized in that: It also includes a wastewater heating device, a wastewater reflux pipeline after reaction and / or a produced gas output pipeline.

6. A method for coupling wastewater COD degradation with hydrogen production, characterized in that: The wastewater in the cathode wastewater replenishing device and the anode wastewater replenishing device flows into the cathode wastewater storage device and the anode wastewater storage device through pipelines; The wastewater from the cathode wastewater storage device and the anode wastewater storage device flows out through pipelines and enters the cathode centrifugal pump and the anode centrifugal pump respectively. The wastewater is transported to the COD degradation hydrogen production reactor through the cathode centrifugal pump and the anode centrifugal pump respectively. Under the action of DC power supply, the cathode side of COD degradation hydrogen production reactor produces hydrogen, and the anode side completes the oxidation of organic matter to reduce COD. The wastewater after the reaction is completed is circulated back to the cathode wastewater storage tank and the anode wastewater storage tank through pipelines for recycling.

7. The wastewater COD degradation coupled hydrogen production method according to claim 6, characterized in that: The cathode wastewater replenishing device and the anode wastewater replenishing device are provided with a wastewater heating device for heating and keeping the wastewater warm; the cathode wastewater storage device and the anode wastewater storage device are provided with a wastewater heating device for heating and keeping the wastewater warm.

8. The wastewater COD degradation coupled hydrogen production method according to claim 7, characterized in that: The temperature of the heating and heat preservation is 40-90°C.

9. The method for coupling wastewater COD degradation with hydrogen production according to any one of claims 6 to 8, characterized in that: The method also includes the steps of post-treating the hydrogen produced on the cathode side of the COD degradation hydrogen production reactor and post-treating the gas produced on the anode side of the COD degradation hydrogen production reactor.

10. The method for coupling wastewater COD degradation with hydrogen production according to any one of claims 6 to 9, characterized in that: The wastewater is selected from one or more of oilfield produced water, chemical wastewater, and urban water; the flow rate of the wastewater in the cathode centrifugal pump and the anode centrifugal pump is 0.1-2 L / min.

Images