Miniaturized chemical oxygen demand (COD) electrochemical detection device and detection method thereof

Abstract

The invention relates to a miniaturized COD (Chemical Oxygen Demand) electrochemical detection device and a detection method thereof. The device comprises a circulating pump, a micron-sized operation unit, an electrode assembly and an electrochemical workstation which are connected in sequence, the micron-sized operation unit is provided with a runway type reaction chamber for accommodating a solution to be detected, an opening for the electrode assembly to extend into the runway type reaction chamber, and a sample introduction pipeline and a water outlet pipeline which are connected with the runway type reaction chamber; the sample introduction pipeline is connected with the circulating pump; the electrode assembly comprises a reference electrode immersed in a solution to be detected, a counter electrode and a working electrode provided with a graphene oxide-copper oxide composite nano material coating; the electrochemical workstation is configured to control the electrode assembly to collect a current value generated in an electrochemical reaction when the solution to be detected is subjected to the electrochemical reaction, and the COD value of the solution to be detected is obtained by combining the association relationship between the COD value and the current value. The method overcomes the problems of long detection time, high detection cost, complex operation and incorrect optical COD detection result in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of COD detection, and in particular to a COD electrochemical detection device and a detection method thereof. Background Art

[0002] Kitchen waste is the waste generated by residents in their daily life. It is easy to deteriorate, rot, and ferment, breed harmful microorganisms and pests, and produce a large amount of toxins and emit stench, polluting the atmosphere and water, seriously affecting the appearance of the city, and damaging the quality of the environment. Improper treatment may also produce carcinogens such as dioxins. The harmlessness, resource utilization, and reduction of kitchen waste, turning waste into treasure, has become a hot topic in scientific research today.

[0003] At present, anaerobic digestion technology is one of the more suitable treatment technologies for the characteristics of food waste at this stage. For the anaerobic digestion of food waste, common inhibitors are volatile fatty acids (VFAs), ammonia nitrogen, long-chain fatty acids (LCFAs) and inorganic salts. The generation of these influencing factors is inevitably related to the concentration of feed COD (Chemical Oxygen Demand, which refers to the amount of oxidants consumed by reducing substances in water samples oxidized by chemical methods under certain conditions) in the reaction system. And the change of organic carbon concentration in the reaction system can indicate the operating efficiency of different stages of the anaerobic digestion process and the collaborative effect between stages.

[0004] Common methods for COD detection include standard chemical oxidation, ultraviolet spectroscopy, and electrochemical advanced oxidation. Traditional methods for COD detection in water have disadvantages such as long time, high temperature operation, use of dangerous reagents, high instrument requirements, unsuitability for on-site testing, organic matter type restrictions, and measurement errors. In addition, the electrochemical COD detectors currently on the market are all based on optical detection. However, the anaerobic fermentation tanks of food waste have complex components, which greatly interfere with the detector and easily cause distortion of the measurement results.

[0005] Therefore, there is an urgent need to develop an efficient and safe COD automatic detection system for kitchen waste during anaerobic fermentation. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a COD electrochemical detection device and a detection method thereof, aiming to complete long-term and high-precision COD online detection during the anaerobic fermentation process of kitchen waste.

[0008] (II) Technical solution

[0009] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0010] In a first aspect, an embodiment of the present invention provides a miniaturized COD electrochemical detection device, which comprises: a circulation pump, a micron-level operation unit, an electrode assembly, and an electrochemical workstation connected in sequence;

[0011] The micron-scale operation unit is provided with a racetrack-type reaction chamber for accommodating a solution to be tested, a fixed opening for the electrode assembly to be inserted into the racetrack-type reaction chamber for detection, and an inlet pipe and an outlet pipe connected to the racetrack-type reaction chamber, wherein the inlet pipe is connected to a circulation pump, and the outlet pipe is connected to a waste liquid barrel;

[0012] The electrode assembly includes a reference electrode, a counter electrode, and a working electrode provided with a graphene oxide-copper oxide composite nanomaterial coating, all of which are immersed in a solution to be tested;

[0013] The electrochemical workstation is configured to control the electrode assembly to collect the current value generated in the electrochemical reaction when the solution to be tested undergoes an electrochemical reaction, and to obtain the COD value of the solution to be tested based on the correlation between the COD value and the current value.

[0014] Optionally, the electrochemical workstation includes: an electrochemical simulation front-end chip, a main controller, and a wireless communication module connected in sequence;

[0015] The electrochemical analog front-end chip is configured to apply an electrical signal to the working electrode to cause the solution to be tested to undergo an electrochemical reaction, and to collect a current value generated by the electrochemical reaction based on the reference electrode and the counter electrode;

[0016] The main controller is configured to obtain the COD value of the solution to be tested based on the correlation between the COD value and the current value when receiving the current value of the electrochemical simulation front-end chip;

[0017] The wireless communication module is configured to send the obtained COD value of the solution to be tested to the user end.

[0018] Optionally, the substrate of the working electrode comprises: a graphite substrate;

[0019] Reference electrodes include: saturated calomel electrode;

[0020] The counter electrode includes: a platinum electrode.

[0021] Optionally, the micron-scale operating unit includes: a microfluidic chip.

[0022] Optionally, the miniaturized COD electrochemical detection device further comprises: a filter, which is arranged on the sampling pipeline to filter solid residues in the solution to be tested.

[0023] Optionally, the miniaturized COD electrochemical detection device includes: an Internet of Things gateway and a cloud platform that are communicatively connected;

[0024] The IoT gateway is connected to the electrochemical workstation via a serial port and is configured to upload the real-time detected COD value of the test solution to the cloud platform.

[0025] In a second aspect, an embodiment of the present invention provides a detection method of a miniaturized COD electrochemical detection device, which is applied to the miniaturized COD electrochemical detection device described above, and includes:

[0026] The electrochemical workstation controls the circulation pump to add a set amount of the solution to be tested into the racetrack-type reaction chamber of the micrometer-level operation unit;

[0027] The electrochemical workstation controls the working electrode based on the chronoamperometry to make the solution to be tested undergo an electrochemical reaction, and obtains the current value at the working electrode after 30 seconds;

[0028] The electrochemical workstation obtains the COD value of the solution to be tested by combining the acquired current value with the pre-established linear regression equation between the COD value and the current value.

[0029] Optionally, before controlling the circulation pump to add a set amount of the solution to be tested into the racetrack-type reaction chamber of the micrometer-scale operation unit, the method further includes:

[0030] The graphene oxide-copper oxide composite nanomaterial is mixed into a solvent having a volume ratio of naphthol to ethanol of 1:1 to obtain a mixed solvent;

[0031] The mixed solvent is dripped onto the working electrode and dried to remove the naphthol-ethanol components in the mixed solvent, thereby obtaining a working electrode having a graphene oxide-copper oxide composite nanomaterial coating.

[0032] Optionally, the pre-established linear regression equation of COD value and current value includes:

[0033] The electrochemical workstation obtains COD information of multiple calibration solutions;

[0034] The electrochemical workstation controls the working electrode based on cyclic voltammetry to make the solution to be tested undergo an electrochemical reaction, and obtains the oxidation peak voltage corresponding to each calibration solution;

[0035] The electrochemical workstation controls the initial voltage of the working electrode to be the oxidation peak voltage based on the chronoamperometry to make the solution to be tested undergo an electrochemical reaction, and obtains the current value at the working electrode after each calibration solution has completely reacted;

[0036] The electrochemical workstation obtains the COD information and current value of each calibration solution, fits the curve of COD value and current value to obtain the linear regression equation of COD value and current value:

[0037] Y=0.43076X+0.02336

[0038] Among them, Y is the current value and X is the COD value.

[0039] Optionally, after the electrochemical workstation obtains the COD value of the solution to be tested by using a pre-established linear regression equation between the COD value and the current value, the method further includes:

[0040] The obtained COD value of the solution to be tested is sent to one or more of the user's mobile terminal, email address, and online chat application through the wireless communication module in the electrochemical workstation;

[0041] and / or

[0042] The obtained COD value of the solution to be tested is uploaded to a pre-set cloud platform (80) based on a pre-set Internet of Things gateway (70).

[0043] (III) Beneficial effects

[0044] The beneficial effects of the present invention are:

[0045] The present invention adopts a technical solution of controlling a circulation pump to transport a set amount of the solution to be tested from an anaerobic fermentation tank to a micron-level operating unit within a set time, and then controls the electrode assembly to cause an electrochemical reaction in the solution to be tested in the micron-level operating unit, and obtains the COD concentration of the solution to be tested by collecting the current value after the oxidation reaction. Compared with the prior art, the present invention greatly shortens the detection time and improves the safety of the detection, and can also achieve real-time detection by setting the time.

[0046] In particular, the present invention adopts a micron-scale operating unit as a reaction pool of the detection device, making the detection device more compact and low-cost, suitable for large-scale preparation; and the micron-scale operating unit adopts a racetrack-type reaction chamber as the COD detection area to prevent bubbles from being generated when the test solution enters the reaction chamber, thereby affecting the COD detection accuracy.

[0047] In addition, the present invention also arranges a graphene oxide-copper oxide composite nanomaterial coating on the surface of the working electrode, which greatly reduces the voltage of the electrode while reducing the oxidation time of the solution to be tested, thereby reducing energy consumption and allowing the detection device to use a smaller battery, further improving the portability of the detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A schematic diagram of a COD electrochemical detection device provided by an embodiment of the present invention;

[0049] Figure 2 A schematic diagram of a micrometer-scale operating unit and a working electrode provided in one embodiment of the present invention;

[0050] Figure 3This is a SEM image of a graphene oxide-copper oxide nanocomposite material provided by one embodiment of the present invention;

[0051] Figure 4 A current-voltage curve diagram of cyclic voltammetry detection of solutions with different glucose concentrations provided by an embodiment of the present invention;

[0052] Figure 5 A current-time curve diagram of chronoamperometry detection of solutions with different glucose concentrations provided by an embodiment of the present invention;

[0053] Figure 6 A glucose concentration-current curve diagram provided in accordance with an embodiment of the present invention.

[0054] [Description of Reference Numerals]

[0055] 10: Anaerobic fermentation tank;

[0056] 20: Filter;

[0057] 30: Circulation pump;

[0058] 40: Micron-level operation unit;

[0059] 50: electrode assembly; 51: graphite substrate; 52: graphene oxide-copper oxide composite nanomaterial coating;

[0060] 60: Electrochemical workstation;

[0061] 70: Internet of Things Gateway;

[0062] 80: Cloud platform. DETAILED DESCRIPTION

[0063] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0064] refer to Figure 1-3As shown, a COD electrochemical detection device proposed in an embodiment of the present invention includes: a circulation pump 30, a micron-level operating unit 40, an electrode assembly 50 and an electrochemical workstation 60 connected in sequence; the micron-level operating unit 40 is provided with a racetrack-type reaction chamber for accommodating a solution to be tested, a fixed opening for the electrode assembly 50 to extend into the racetrack-type reaction chamber for detection, and an inlet pipe and a water outlet pipe connecting the racetrack-type reaction chamber, the inlet pipe is connected to the circulation pump 30, and the water outlet pipe is connected to a waste liquid barrel; the electrode assembly 50 includes a reference electrode, a counter electrode and a working electrode provided with a graphene oxide-copper oxide composite nanomaterial coating 52, all of which are immersed in the solution to be tested; the electrochemical workstation 60 is configured to control the electrode assembly 50 to collect the current value generated in the electrochemical reaction when the solution to be tested undergoes an electrochemical reaction, and obtain the COD value of the solution to be tested in combination with the correlation between the COD value and the current value.

[0065] The present invention adopts a technical solution of controlling the circulation pump 30 to transport a set amount of the solution to be tested from the anaerobic fermentation tank 10 to the micron-level operating unit 40 within a set time, and then controls the electrode assembly 50 to cause the solution to be tested in the micron-level operating unit 40 to undergo an electrochemical reaction, and obtains the COD concentration of the solution to be tested by collecting the current value after the oxidation reaction. Compared with the prior art, the present invention greatly shortens the detection time and improves the safety of the detection, and can also achieve real-time detection by setting the time.

[0066] In particular, the present invention adopts a micron-sized operating unit 40 as a reaction pool of the detection device, making the detection device more compact and low-cost, suitable for large-scale preparation; and the micron-sized operating unit 40 adopts a racetrack-type reaction chamber as the COD detection area to prevent bubbles from being generated when the test solution enters the reaction chamber, thereby affecting the COD detection accuracy.

[0067] In addition, the present invention also arranges a graphene oxide-copper oxide composite nanomaterial coating 52 on the surface of the working electrode, which greatly reduces the voltage of the electrode while reducing the oxidation time of the solution to be tested, thereby reducing energy consumption and allowing the detection device to use a smaller battery, further improving the portability of the detection device.

[0068] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0069] Among them, the micron-scale operation unit 40 includes: a microfluidic chip. The microfluidic chip is a micron-scale chip, which is provided with a racetrack-type reaction chamber for accommodating the solution to be tested to undergo an electrochemical reaction. The racetrack-type reaction chamber is connected to the outside through a sample supply pipe and a water outlet pipe. The sample supply pipe is connected to a circulation pump 30, and the water outlet pipe is connected to a waste liquid barrel. Driven by the circulation pump 30, the solution to be tested is added to the racetrack-type reaction chamber and / or discharged from the racetrack-type reaction chamber. A fixed opening is also provided above the racetrack-type reaction chamber for the electrode assembly 50 to extend into the racetrack-type reaction chamber for COD detection.

[0070] Further explanation, the electrochemical workstation 60 includes: an electrochemical simulation front-end chip, a main controller and a wireless communication module connected in sequence. The electrochemical simulation front-end chip integrates the entire three-electrode system chain, including a constant potential circuit, an operational amplifier circuit, a bias voltage generation circuit, a signal detection circuit and a central control circuit. The electrochemical simulation front-end chip applies an electrical signal to the working electrode to cause the solution to be tested in the micron-level operating unit 40 to undergo an electrochemical reaction, and collects the current value generated by the electrochemical reaction based on the reference electrode and the counter electrode. When the main controller receives the current value of the electrochemical simulation front-end chip, it calculates the COD value of the solution to be tested based on the linear regression equation of the COD value and the current value. The wireless communication module sends the COD value of the solution to be tested to one or more of the user's mobile terminal, email address and online chat application.

[0071] Further explanation, the COD electrochemical detection device also includes: a filter 20, an Internet of Things gateway 70 and a cloud platform 80. The filter 20 is arranged on the sampling pipeline to filter the solid residue in the solution to be tested. The Internet of Things gateway 70 is connected to the main controller in the electrochemical workstation 60 through the RS485 serial port, and the Internet of Things gateway 70 is connected to the gateway control software of the host computer through a network cable, and the gateway control software is connected to the cloud platform 80. After completing the COD detection of the solution to be tested, the test results are uploaded to the cloud platform 80 for data storage, so that the staff can check the COD changes in the anaerobic fermentation tank 10 at any time.

[0072] It is worth mentioning that the working electrode substrate is a graphite substrate 51, and after the graphene oxide-copper oxide composite nanomaterial coating 52 is provided on the graphite substrate 51, the time for the solution to be tested to be completely oxidized is 30 seconds. A saturated calomel electrode is selected as the reference electrode, and a platinum electrode is selected as the counter electrode.

[0073] On the other hand, an embodiment of the present invention provides a detection method applied to the above-mentioned COD electrochemical detection device, comprising:

[0074] S1 . The electrochemical workstation 60 controls the circulation pump 30 to add a set amount of the solution to be tested into the racetrack-shaped reaction chamber of the micrometer-scale operation unit 40 .

[0075] S2. The electrochemical workstation 60 controls the working electrode to operate based on the chronoamperometry to cause the solution to be tested to undergo an electrochemical reaction, and obtains the current value at the working electrode after 30 seconds.

[0076] S3. The electrochemical workstation 60 obtains the COD value of the solution to be tested by combining the acquired current value with a pre-established linear regression equation between the COD value and the current value.

[0077] S4. The obtained COD value of the solution to be tested is sent to one or more of the user's mobile terminal, email address, and online chat application through the wireless communication module in the electrochemical workstation 60; and / or, the obtained COD value of the solution to be tested is uploaded to the cloud platform 80 based on the Internet of Things gateway 70.

[0078] Further description, before step S1, it also includes:

[0079] F1. Mixing the graphene oxide-copper oxide composite nanomaterial into a solvent in which the volume ratio of naphthol to ethanol is 1:1 to obtain a mixed solvent.

[0080] F2. Add the mixed solvent dropwise onto the working electrode and dry it to remove the naphthol-ethanol components in the mixed solvent, thereby obtaining a working electrode having a graphene oxide-copper oxide composite nanomaterial coating 52 .

[0081] Further, the method steps of the linear regression equation of COD value and current value pre-established in step S3 include:

[0082] S31 . The electrochemical workstation 60 obtains COD information of a plurality of calibration solutions.

[0083] S32, the electrochemical workstation 60 controls the working electrode to operate based on cyclic voltammetry to cause an electrochemical reaction in the solution to be tested, and obtains the oxidation peak voltage corresponding to each calibration solution.

[0084] S33. The electrochemical workstation 60 controls the initial voltage of the working electrode to be the oxidation peak voltage based on the chronoamperometry to cause the solution to undergo an electrochemical reaction, and obtains the current value at the working electrode after each calibration solution has completely reacted.

[0085] S34, the electrochemical workstation 60 obtains the COD information and current value of each calibration solution, and fits the curve of COD value and current value to obtain the linear regression equation of COD value and current value:

[0086] Y=0.43076X+0.02336

[0087] Among them, Y is the current value and X is the COD value.

[0088] In a specific embodiment, a solution in which the organic matter is glucose is selected to establish a linear regression equation between COD value and current value. First, the COD electrochemical detection device uses cyclic voltammetry to detect each glucose solution, and then establishes a linear regression equation based on the detection results. Figure 4 The current-voltage curve is shown in the figure, and the corresponding oxidation peak voltage of each glucose solution is found from the current-voltage curve. Then, the COD electrochemical detection device uses the chronoamperometry to detect each glucose solution. The initial voltage of the working electrode is the oxidation peak voltage. Based on the detection results, the following is established: Figure 5 The current-time curve shown in the figure is used, and the current value after the solution is completely reacted is taken from the current-time curve of each glucose solution as the current value corresponding to the glucose concentration. Finally, the following is established: Figure 6 The glucose concentration-current curve shown in FIG. 1 is used to obtain a linear regression equation between glucose concentration and current value. At the same time, based on the glucose concentration of the solution = the COD value of the solution, a linear regression equation between COD value and current value can be derived.

[0089] In summary, the COD electrochemical detection device provided by the present invention comprises: a micron-level operating unit 40, an electrode assembly 50 and an electrochemical workstation 60. The micron-level operating unit 40 adopts a racetrack-type reaction chamber as the detection area of ​​COD to prevent bubbles from being generated when the solution to be tested enters the reaction chamber, and it is more compact and low-cost, suitable for large-scale preparation. The electrode assembly 50 and the electrochemical workstation 60 constitute a complete three-electrode system chain, which can complete detection methods such as cyclic voltammetry and chronoamperometry. In addition, the working electrode of the electrode assembly 50 adopts graphite as a substrate, and a graphene oxide-copper oxide composite nanomaterial coating 52 is arranged on the surface of the substrate, and the oxidation time is controlled to 30 seconds, which greatly shortens the detection time.

[0090] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0091] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions.

[0092] It should be noted that in the claims, any reference numerals placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the claims enumerating several means, several of these means may be embodied by the same hardware. The use of the words first, second, third, etc., is for convenience of expression only and does not indicate any order. These words may be understood as part of the component name.

[0093] In addition, it should be noted that, in the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0094] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments after knowing the basic creative concept. Therefore, the claims should be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0095] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention should also include these modifications and variations.

Claims

1. A miniaturized COD electrochemical detection device, It is characterized in that include: A circulating pump (30), a micron-level operating unit (40), an electrode assembly (50), and an electrochemical workstation (60) connected in sequence; The micrometer-level operation unit (40) is provided with a racetrack-shaped reaction chamber for accommodating a solution to be tested, a fixed opening for the electrode assembly (50) to extend into the racetrack-shaped reaction chamber for detection, and a sample inlet pipe and a water outlet pipe connected to the racetrack-shaped reaction chamber, wherein the sample inlet pipe is connected to a circulation pump (30) and the water outlet pipe is connected to a waste liquid bucket; The electrode assembly (50) comprises a reference electrode, a counter electrode and a working electrode provided with a graphene oxide-copper oxide composite nanomaterial coating (52), all of which are immersed in a solution to be tested; The electrochemical workstation (60) is configured to control the electrode assembly (50) to collect the current value generated in the electrochemical reaction when the solution to be tested undergoes an electrochemical reaction, and to obtain the COD value of the solution to be tested by combining the correlation between the COD value and the current value.

2. The miniaturized COD electrochemical detection device according to claim 1, It is characterized in that The electrochemical workstation (60) comprises: an electrochemical simulation front-end chip, a main controller and a wireless communication module which are connected in sequence; The electrochemical analog front-end chip is configured to apply an electrical signal to the working electrode to cause the solution to be tested to undergo an electrochemical reaction, and to collect a current value generated by the electrochemical reaction based on the reference electrode and the counter electrode; The main controller is configured to obtain the COD value of the solution to be tested based on the correlation between the COD value and the current value when receiving the current value of the electrochemical simulation front-end chip; The wireless communication module is configured to send the obtained COD value of the solution to be tested to the user end.

3. The miniaturized COD electrochemical detection device according to claim 1, It is characterized in that The substrate of the working electrode comprises: a graphite substrate (51); Reference electrodes include: saturated calomel electrode; The counter electrode includes: a platinum electrode.

4. The miniaturized COD electrochemical detection device according to claim 1, It is characterized in that The micron-scale operation unit (40) comprises: a microfluidic chip.

5. The miniaturized COD electrochemical detection device according to claim 1, It is characterized in that include: The filter (20) is arranged on the sampling pipeline to filter the solid residue in the solution to be tested.

6. The miniaturized COD electrochemical detection device according to claim 1, It is characterized in that include: An Internet of Things gateway (70) and a cloud platform (80) that are communicatively connected; The Internet of Things gateway (70) is connected to the electrochemical workstation (60) via a serial port, and is configured to upload the COD value of the solution to be tested detected in real time to a cloud platform (80).

7. A detection method of a miniaturized COD electrochemical detection device, It is characterized in that The miniaturized COD electrochemical detection device as claimed in claims 1 to 6 comprises: The electrochemical workstation (60) controls the circulation pump (30) to add a set amount of the solution to be tested into the racetrack-shaped reaction chamber of the micrometer-level operation unit (40); The electrochemical workstation (60) controls the working electrode to operate based on the chronoamperometry method so that the solution to be tested undergoes an electrochemical reaction, and obtains the current value at the working electrode after 30 seconds; The electrochemical workstation (60) obtains the COD value of the solution to be tested by combining the acquired current value with a pre-established linear regression equation between the COD value and the current value.

8. The detection method of the miniaturized COD electrochemical detection device according to claim 7, It is characterized in that Before controlling the circulation pump (30) to add a set amount of the solution to be tested into the racetrack-type reaction chamber of the micron-scale operation unit (40), the method further includes: The graphene oxide-copper oxide composite nanomaterial is mixed into a solvent having a volume ratio of naphthol to ethanol of 1:1 to obtain a mixed solvent; The mixed solvent is dripped onto the working electrode and dried to remove the naphthol-ethanol components in the mixed solvent, thereby obtaining a working electrode having a graphene oxide-copper oxide composite nanomaterial coating (52).

9. The detection method of the miniaturized COD electrochemical detection device according to claim 7, It is characterized in that The pre-established linear regression equations for COD value and current value include: The electrochemical workstation (60) obtains COD information of a plurality of calibration solutions; The electrochemical workstation (60) controls the working electrode to operate based on cyclic voltammetry so that the solution to be tested undergoes an electrochemical reaction, thereby obtaining an oxidation peak voltage corresponding to each calibration solution; The electrochemical workstation (60) controls the initial voltage of the working electrode to be the oxidation peak voltage based on the chronoamperometry to allow the solution to undergo an electrochemical reaction, and obtains the current value at the working electrode after each calibration solution has completely reacted; The electrochemical workstation (60) obtains the COD information and current value of each calibration solution, and fits the curve of COD value and current value to obtain the linear regression equation of COD value and current value: Y=0.43076X+0.02336 Among them, Y is the current value and X is the COD value.

10. The detection method of the miniaturized COD electrochemical detection device according to claim 7, It is characterized in that After the electrochemical workstation (60) obtains the COD value of the solution to be tested by using a pre-established linear regression equation between the COD value and the current value, the method further includes: The obtained COD value of the solution to be tested is sent to one or more of a user's mobile terminal, an email address, and an online chat application via a wireless communication module in the electrochemical workstation (60); and / or The obtained COD value of the solution to be tested is uploaded to a pre-set cloud platform (80) based on a pre-set Internet of Things gateway (70).

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