Portable detection device and method for total discharge amount of water pollutants

Abstract

The invention belongs to the technical field of water environment detection, and particularly relates to a portable detection device and method for the total discharge amount of water pollutants. The portable detection device at least comprises a three-electrode sensor module, a potentiostat module, an analog-to-digital conversion module, a microcontroller, a peripheral circuit of the microcontroller, a Bluetooth module and a power module, and the three-electrode sensor module comprises a working electrode coated with a tungsten oxide film, a reference electrode and a counter electrode; the constant potential rectifier comprises at least two electrode channels, is connected with the microcontroller and the analog-to-digital conversion module and is used for controlling voltage to detect hydrology and water quality parameters; and the Bluetooth module is used for being paired with intelligent equipment to transmit data. The portable water environment detection device and the hydrology and water quality synchronous detection method can be provided, the problem that scattered and small drain outlets cannot be detected is effectively solved, and the detection device is provided for real-time online evaluation of the total discharge amount of water pollutants.

Description

Technical Field

[0001] This invention belongs to the technical field of water environment monitoring, and particularly relates to a portable monitoring device and method for detecting the total amount of water pollutants discharged. Background Technology

[0002] In many regions, rapid urbanization and industrialization have exacerbated water pollution problems. Among these, numerous and dispersed small sewage outlets scattered throughout urban and industrial areas are difficult to monitor and manage effectively, posing a significant challenge to controlling total water pollution discharge. Effective control of total water pollution discharge requires on-site monitoring of the water environment at these scattered outlets, measuring both pollutant concentrations and water flow rates. However, traditional water pollution monitoring methods primarily focus on large discharge sources and major water bodies, limiting their effectiveness in monitoring these small outlets. Therefore, a crucial issue is how to conduct on-site, pollution-free, and simultaneous monitoring of hydrological and water quality indicators to achieve real-time online assessment of total water pollutant discharge.

[0003] Water environment monitoring can be divided into water quality monitoring and hydrological monitoring. In the field of hydrological monitoring, many sewage outlets discharge continuously or at rates below the flow trigger, making existing low-flow-rate detection equipment unusable or causing complex measurement systems. Therefore, there is a widespread demand for stable, easy-to-operate, and computationally simple low-flow-rate liquid sensors. Similarly, in the field of water quality monitoring, existing water quality monitoring equipment often measures traditional indicators such as pH, conductivity, and dissolved oxygen, providing only limited information about the water body. Polluted water bodies also contain highly water-soluble heavy metals, which are difficult to detect in a timely manner without specific detection technologies or methods. Currently, conventional heavy metal ion detection relies on laboratory environments, which has considerable limitations and is not easy to operate on-site.

[0004] Electrochemical methods are an important method for trace and high-precision detection and analysis. They are simple to operate and easy to make portable, and can be applied to the rapid detection of heavy metal concentrations and the accurate detection of low-flow-rate liquids.

[0005] Therefore, this invention develops a portable electrochemical detection device for total water pollutant discharge from scattered and small sewage outlets in urban areas, and proposes a new method for simultaneous hydrological and water quality monitoring. This invention features pollution-free operation, simple on-site operation, high sensitivity, and simultaneous hydrological and water quality monitoring, effectively solving the problem of difficulty in detecting total pollutant discharge from scattered and small sewage outlets. It is of great significance for water environment monitoring, environmental inspection, and environmental supervision. Summary of the Invention

[0006] This invention provides a portable detection device and method for total water pollutant discharge from scattered and small sewage outlets in cities, overcoming the limitations of traditional methods, the lack of portability of detection instruments, and the high cost of detection. This invention employs an electrochemical method, designing an electrochemical water environment analysis instrument equipped with a pollution-free tungsten oxide electrode sensor to detect water quality and hydrology. During heavy metal detection, the device controls the voltage signal of the three-electrode electrochemical sensor through a digital-to-analog converter module, causing a redox reaction between heavy metals in the water and the working electrode, resulting in a change in current. The reaction current is collected and transmitted to a smart device terminal to calculate the heavy metal concentration in the water. Similarly, during flow velocity detection, the kinetic effect characteristics of the tungsten oxide electrode are utilized, i.e., the potential change of the tungsten oxide electrode in the flowing liquid is generated by the flow potential. The potential signal is collected by a built-in SAADC module in the microcontroller and finally transmitted to the smart device terminal to calculate the liquid flow velocity. Ultimately, this achieves real-time online assessment of total water pollutant discharge.

[0007] The problem to be solved by this invention is achieved through the following techniques:

[0008] Firstly, this invention provides a portable detection device for total water pollutant discharge. The detection device includes at least a three-electrode sensor module, a potentiostat module, an analog-to-digital converter module, a microprocessor and its peripheral circuits, a Bluetooth module, and a power supply module. Its block diagram is shown below. Figure 1 As shown, the potentiostat module is as follows: Figure 2 As shown, the analog-to-digital conversion module is as follows: Figure 3 As shown, the microprocessor and its peripheral circuits are as follows: Figure 4 As shown, and the power module as follows Figure 5 As shown.

[0009] The three-electrode sensor module includes a working electrode, a reference electrode, and a counter electrode. The working electrode is coated with a tungsten oxide thin film and is called a tungsten oxide electrode. The reference electrode is a silver-silver chloride electrode, and the counter electrode is a platinum wire electrode. The three-electrode sensor module is connected to an analog-to-digital converter module to generate an excitation signal to convert digital quantities into analog quantities, and to a potentiostat module to collect signals generated in the reaction cell during the electrochemical reaction process. Pins 7 and 8 of the DA converter input terminal in the analog-to-digital converter module are connected to the output terminal of the microprocessor. The microprocessor and its peripheral circuits are connected to the potentiostat module and the Bluetooth module. The power supply module includes a Type-C charging circuit and a charge detection circuit.

[0010] Furthermore, the tungsten oxide working electrode is subjected to electrochemical oxidation of the tungsten electrode in a 0.1M H2SO4 solution, cyclically for 20 cycles at a scan rate of 0.02V / s between 1V and 2V, and then immersed in the same solution for 12h; the silver-silver chloride electrode reference electrode provides a reference potential for the entire system.

[0011] Furthermore: the analog-to-digital conversion module includes an AD5647 chip and its peripheral circuitry;

[0012] The analog-to-digital converter (ADC) module utilizes a DAC module to output analog signals. The AD5647 is a dual-channel voltage-output DAC converter, connected to a microcontroller to control the voltage of the working and reference electrodes, thereby enabling cyclic voltammetry, time-current method, and square-wave voltammetry scanning. Pin 1 of the AD5647 chip is the first output terminal, connected to the first input terminal of the potentiostat module; pin 2 is the second output terminal, connected to the second input terminal of the potentiostat module; pins 3, 4, 5, and 6 are grounded; pin 7 is the SCL pin used for communication by the AD5647 chip; pin 8 is the SDA pin used for communication by the AD5647 chip; pin 10 is the 3.3V power input pin, connected to one end of filter capacitor C1 and one end of filter capacitor C2; the other ends of capacitors C1 and C2 are connected to ground.

[0013] Furthermore: the potentiostat module includes a voltage bias circuit, an IV conversion circuit, and peripheral circuits; the potentiostat module includes at least two channels;

[0014] The potentiostat module uses a voltage bias circuit to precisely control the potential of the working electrode, enabling precise control of the electrochemical reaction. The current generated after the electrochemical reaction is converted into a voltage signal through an IV conversion circuit. The AD8608 chip is a four-channel operational amplifier. Its pin 1 is connected to pin 2 and one end of resistor R6; pin 3 is connected to ground, capacitor C8, and one end of resistor R5; R4 is connected to pin 1 of the AD5647 chip; the other end of resistor R4 is connected to capacitor C10 and one end of resistor R5; the other end of capacitor C10 is connected to pin 2; pin 4 is the 3.3V power input pin; pin 11 is grounded; pin 5 is connected to one end of resistor R7 and the ground pin; pin 6 is connected to capacitor C11 and pin 7; pin 7 is connected to pin 10; pin 8 is connected to the counter electrode; pin 9 is connected to the reference electrode; the reference electrode is connected to M... Pin 2 of the AX4641 chip is connected; pin 6 is connected to pin 2 of the AD5647 chip; pin 7 of the MAX4641 chip is connected to the third output of the microcontroller; pin 8 is the 3.3V power input pin; pin 5 is connected to the working electrode; pin 12 of the AD5647 chip is connected to pin 5 of the MAX4641 chip; pin 13 of the AD5647 chip is connected to one end of capacitor C17 and resistor R12 respectively; pin 14 of the AD5647 chip is connected to the other end of capacitor C17, the other end of resistor R12, and one end of resistor R13 respectively; the other end of resistor R13 is connected to the ADC acquisition terminal of the microcontroller.

[0015] Furthermore: the power module includes a Type-C charging circuit and a charge level detection circuit;

[0016] The Type-C charging circuit consists of a TP4056-42 charging chip, a Type-C charging interface, and peripheral circuitry. Pins 1, 3, and 9 of the TP4056-42 charging chip are grounded; pin 2 is connected to grounding resistor R16; pin 4 is connected to one end of capacitors C12 and C13 respectively, with the other end of capacitors C12 and C13 grounded; pin 5 is connected to one end of capacitors C14 and C16 respectively, with the other end of capacitors C14 and C16 grounded; pin 6 is connected to one end of resistor R15, with the other end of R15 connected to +5V; pin 7 is connected to one end of resistor R14, with the other end of R14 connected to +5V.

[0017] On the other hand, this invention provides a method for detecting the total discharge of water pollutants, which utilizes an electrochemical method to achieve simultaneous on-site detection of hydrology and water quality.

[0018] Includes the following steps:

[0019] Step 1: Place the tungsten oxide working electrode, reference electrode, and counter electrode in a flowing liquid and connect them to the portable detection device with wires;

[0020] Step 2: Set the parameters for the open-circuit voltage method on the smart device and send them to the three-electrode sensor module for flow rate detection; set the enrichment voltage and enrichment time in the current-time method and the working electrode voltage, reference electrode voltage, and scan time in the square wave voltammetry method, and send them to the three-electrode sensor module for heavy metal concentration detection.

[0021] Step 3: During the heavy metal concentration detection process, the intelligent device sends parameters to the microcontroller, which generates a voltage excitation signal and sends it to the potentiostat module. The voltage excitation signal controls the working electrode and reference electrode in the three-electrode sensor module to produce a chemical reaction. This process generates current. The reaction current is collected by the operational amplifier and the data is transmitted to the intelligent device terminal to present the IE dissolution curve, thereby calculating the heavy metal concentration in the water.

[0022] Step 4: During the flow velocity detection process, the smart device sends parameters to the microcontroller via Bluetooth module. The tungsten oxide working electrode generates a flow potential in the flowing water. The potential signal is collected by the ADC module in the microcontroller, and the data is transmitted to the smart device terminal. A curve is established to obtain the logarithmic function relationship between the open circuit voltage and the flow velocity, and the water flow velocity is obtained.

[0023] Step 5: Using a combination of environmental monitoring and statistical methods, conduct on-site monitoring at least every other month to measure the drainage flow rate and pollutant discharge concentration. Based on the water heavy metal concentration measured in Step 3 and the water flow rate measured in Step 4, conduct a real-time online assessment of the total amount of water pollutants discharged.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention achieves the synchronization of hydrological and water quality indicator detection, thereby enabling real-time online assessment of total water pollutant discharge.

[0026] The detection device in this invention is small and portable, which overcomes the limitations of traditional post-sampling laboratory testing methods;

[0027] This invention utilizes the characteristic that the open-circuit potential of the tungsten oxide electrode in a flowing liquid has a good linear relationship with the logarithm of the flow velocity to establish a method for measuring flow velocity, thus solving the complexity of traditional flow velocity measurement systems.

[0028] This invention enables pollution-free detection of hydrological and water quality indicators by using an electrochemical sensor, eliminating the need to add substances to the water for detection, such as fluorescent agent tracking methods, thereby avoiding secondary pollution of the water.

[0029] The sensor of the present invention consists of a tungsten oxide working electrode, a silver-silver chloride reference electrode, and a platinum wire counter electrode. The sensor can detect both the concentration of heavy metals in water and the flow rate of water. Attached Figure Description

[0030] Figure 1 This is a block diagram illustrating the principle of the portable detection device in this invention;

[0031] Figure 2 This is a diagram of the potentiostat module in this invention;

[0032] Figure 3 This is a diagram of the analog-to-digital conversion module in this invention;

[0033] Figure 4 This is a diagram of the microprocessor and its peripheral circuits in this invention;

[0034] Figure 5 This is a diagram of the power supply module in this invention;

[0035] Figure 6 This is a detection curve using cadmium as an example in this invention;

[0036] Figure 7 This is a graph showing the voltage variation under different flow rates measured in this invention; Specific implementation steps

[0037] The technical solutions in the embodiments of the present invention will be further described below with reference to the accompanying drawings. Obviously, the described embodiments are only some implementations of the present invention, and not all of them.

[0038] The term "person skilled in the art" or its synonyms, as used in this document, refers to an individual who is aware of all common technical knowledge in the technical field to which the invention pertains prior to the filing date or priority date of this application, is able to access all prior art in that field, and has the ability to apply conventional experimental methods prior to that date. If the technical problem to be solved can prompt a person skilled in the art to seek technical means in other technical fields, they should also have the ability to access relevant prior art, common technical knowledge, and conventional experimental methods prior to the filing date or priority date from those other technical fields.

[0039] Furthermore, without being disclosed in the prior art, any technical features or embodiments described herein shall be regarded as intellectual achievements resulting from the applicant's creative labor.

[0040] Specific embodiments of the present invention are as follows:

[0041] Example 1

[0042] Testing locations were selected based on the following criteria: the sewage discharge section had a regular geometric shape, and the production process of the discharging unit was continuous and stable. Ten testing points were set up at distances of 10m, 20m, 30m, 40m, 50m, 60m, 70m, 80m, 90m, and 100m from the factory. Instantaneous sampling was used for testing. Water samples were collected simultaneously with the testing, and ten samples were taken. The on-site test results were compared with the laboratory instrument test results.

[0043] Taking cadmium ions as an example, heavy metal detection employs anodic stripping voltammetry, while flow rate is detected using open-circuit potential method. Initial optimization experiments were conducted to select suitable enrichment time and voltage, resulting in an enrichment time of 200 s and an enrichment voltage of -1.1 V. The working electrode, reference electrode, and counter electrode were placed in the flowing liquid and connected to the portable detection device via wires. First, enrichment was performed at -1.1 V for 200 s; then, stripping was performed using square wave voltammetry, scanning voltage from -1 V to 0 V. The ADC sampling rate in the microcontroller was set to the maximum sampling frequency of 35.7 kHz, and the settling time was set to 20 s.

[0044] Simultaneously with heavy metal detection, the flow velocity was measured using the open-circuit potential method. A three-electrode sensor module was connected to a portable device via wires and placed in the flowing liquid at the detection point. The smart device transmitted the open-circuit voltage method parameters to the microcontroller via Bluetooth, with the following parameters: running time 100s. The tungsten oxide working electrode generated a flow potential in the flowing water, and the potential signal was acquired by the ADC module in the microcontroller, with the ADC sampling rate set to a maximum sampling frequency of 35.7kHz.

[0045] Finally, the peak current data and open-circuit voltage data obtained by square wave voltammetry scanning are transmitted to the intelligent device terminal to establish the fitting relationship between the peak current magnitude and the heavy metal concentration, and the fitting relationship between the open-circuit voltage magnitude and the logarithm of the solution flow rate, and the heavy metal concentration and liquid flow rate in the water are calculated.

[0046] Heavy metal test results as follows Figure 6 As shown in the IE dissolution curve, a dissolution peak of cadmium ions can be clearly seen at around -0.8V. The magnitude of the dissolution peak current corresponds to the concentration of cadmium ions, indicating that the concentration of heavy metals increases with increasing distance from the factory.

[0047] The flow velocity detection results are shown in Table 2. Figure 7 This is a graph showing the change in potential at different flow velocities measured in this invention. At an average flow velocity of 0.5 mm / s, the voltage drifted by about 5 mV. The open-circuit voltage also changed at flow velocities of 2 mm / s, 4 mm / s, and 8 mm / s. The open-circuit voltage was linearly fitted to the logarithm of the flow velocity to establish a curve and obtain the functional relationship between the logarithm of the flow velocity and the open-circuit voltage, thus obtaining the water flow velocity.

[0048] Table 1. Heavy metal detection results:

[0049] Table 2 Flow velocity detection results:

[0050] Using a combination of environmental monitoring and statistical methods, on-site monitoring is conducted at least every other month to measure drainage flow rate and pollutant discharge concentration. Based on the water heavy metal concentration measured in step 3 and the water flow rate measured in step 4, the total amount of water pollutants discharged is assessed in real time online.

[0051] This invention utilizes electrochemical technology to design an electrochemical water environment analysis instrument, equipped with a pollution-free tungsten oxide electrode sensor to detect water quality and hydrology. It provides both a portable detection device for total water pollutant discharge and a pollution-free rapid detection method, overcoming the limitations of traditional methods, the lack of portability of detection instruments, and the high cost of detection. It can effectively solve the problem of difficulty in detecting the total amount of pollution discharged from scattered and small sewage outlets, providing a detection device for real-time online assessment of total water pollutant discharge.

[0052] The embodiments listed above are typical and preferred embodiments of the present invention, and are only used to describe and explain the technical solutions of the present invention in detail so as to facilitate the reader's understanding. They are not intended to limit the scope of protection or application of the present invention.

Claims

1. A portable detection device for total water pollutant discharge, characterized in that, It includes at least: a three-electrode sensor module, a potentiostat module, an analog-to-digital converter module, a microcontroller and its peripheral circuits, a Bluetooth module, and a power supply module, wherein the three-electrode sensor module includes at least two sensors, and the potentiostat module includes at least two channels; The three-electrode sensor module includes a working electrode, a reference electrode, and a counter electrode, and is connected to a potentiostat. The working electrode is coated with a tungsten oxide film and is called a tungsten oxide electrode. The reference electrode is a silver-silver chloride electrode, and the counter electrode is a platinum wire electrode. The potentiostat is connected to a microcontroller and an analog-to-digital converter (ADC) module to control the electrode potentials and achieve precise control of the electrochemical reaction. Pins 7 and 8 of the DA converter input in the ADC module are connected to the output of the microcontroller. The microcontroller and its peripheral circuits are connected to the potentiostat module and a Bluetooth module. The Bluetooth module is used for pairing with smart devices to transmit data. The power module includes a Type-C charging circuit and a charge level detection circuit.

2. The portable detection device for total water pollutant discharge according to claim 1, characterized in that: The tungsten oxide working electrode is subjected to electrochemical oxidation of the tungsten electrode in a 0.1M H2SO4 solution, cyclically for 20 cycles at a scan rate of 0.02V / s between 1 and 2V, and then immersed in the same solution for 12 hours to finally form a tungsten oxide film.

3. The portable detection device for total water pollutant discharge according to claim 1, characterized in that: The three-electrode sensor module is connected to the analog-to-digital converter module at the front to generate excitation signals to convert digital quantities into analog quantities, and to the potentiostat module at the rear to collect signals generated in the reaction cell during the electrochemical reaction process.

4. A portable detection device for total water pollutant discharge according to claim 1, characterized in that: The AD8608 chip in the potentiostat is a four-channel operational amplifier. Its pin 1 is connected to pin 2 and one end of resistor R6; pin 3 is connected to ground capacitor C8 and one end of resistor R5; R4 is connected to pin 1 of the AD5647 chip; the other end of resistor R4 is connected to capacitor C10 and one end of resistor R5; the other end of capacitor C10 is connected to pin 2; pin 4 is the 3.3V power input pin; pin 11 is grounded; pin 5 is connected to one end of resistor R7 and the ground pin; pin 6 is connected to capacitor C11 and pin 7; pin 7 is connected to pin 10; pin 8 is connected to the counter electrode; pin 9 is connected to the reference electrode; the reference electrode... Pin 12 is connected to pin 2 of the MAX4641 chip; pin 6 is connected to pin 2 of the AD5647 chip; pin 7 of the MAX4641 chip is connected to the third output terminal of the microcontroller; pin 8 is the 3.3V power input pin; pin 5 is connected to the working electrode; pin 12 of the AD5647 chip is connected to pin 5 of the MAX4641 chip; pin 13 of the AD5647 chip is connected to one end of capacitor C17 and resistor R12 respectively; pin 14 of the AD5647 chip is connected to the other end of capacitor C17, the other end of resistor R12, and one end of resistor R13 respectively; the other end of resistor R13 is connected to the ADC acquisition terminal of the microcontroller.

5. A portable detection device for total water pollutant discharge according to claim 1, characterized in that: The analog-to-digital converter module uses a DAC module to output analog signals. Pin 1 of the AD5647 chip is the first output terminal, connected to the first input terminal of the potentiometer module; pin 2 is the second output terminal, connected to the second input terminal of the potentiometer module; pins 3, 4, 5, and 6 are grounded; pin 7 is the SCL pin used for communication by the AD5647 chip; pin 8 is the SDA pin used for communication by the AD5647 chip; pin 10 is a 3.3V power input pin, connected to one end of filter capacitor C1 and one end of filter capacitor C2; the other ends of capacitors C1 and C2 are connected to ground.

6. A portable detection method for total water pollutant discharge, characterized in that, The detection method of the portable water environment detection device includes: Step 1: Place the three-electrode sensor module in a flowing liquid and connect it to the portable detection device with a wire; Step 2: Set the parameters for the open-circuit voltage method on the smart device and send them to the three-electrode sensor module for flow rate detection; set the enrichment voltage and enrichment time in the current-time method and the working electrode voltage, reference electrode voltage, and scan time in the square wave voltammetry method, and send them to the three-electrode sensor module for heavy metal concentration detection. Step 3: During the heavy metal detection process, the intelligent device sends parameters to the microcontroller, which generates a voltage excitation signal and sends it to the potentiostat module. The voltage excitation signal controls the working electrode and reference electrode in the three-electrode sensor module to produce a chemical reaction. The reaction current is collected by the operational amplifier, and the data is transmitted to the smartphone terminal to present the IE dissolution curve, thereby calculating the heavy metal concentration in the water. Step 4: During the flow velocity detection process, the smart device sends parameters to the microcontroller via Bluetooth module. The microcontroller's ADC module collects the potential signal, transmits the data to the smartphone terminal, establishes a curve to obtain the logarithm of the flow velocity and the open-circuit voltage function relationship, and obtains the water flow velocity. Step 5: Using a combination of environmental monitoring and statistical methods, conduct on-site monitoring at least every other month to measure the drainage flow rate and pollutant discharge concentration. Based on the water heavy metal concentration measured in Step 3 and the water flow rate measured in Step 4, conduct a real-time online assessment of the total amount of water pollutants discharged.

7. A portable detection method for total water pollutant discharge according to claim 6, characterized in that: In step 2, the enrichment time is 200s, the enrichment voltage is -1.1V, the square wave voltammetry scanning potential is -1V to 0V, the ADC sampling rate in the microcontroller is set to the maximum sampling frequency of 35.7kHz, and the rest time is set to 20s.

8. A portable detection method for total water pollutant discharge according to claim 6, characterized in that: In step 3, the chemical reaction is a redox reaction of heavy metal ions in the solution. During enrichment, the heavy metals are deposited on the surface of the working electrode. During dissolution, the heavy metals undergo an oxidation reaction, and this process generates an electric current.

9. A portable detection method for total water pollutant discharge according to claim 6, characterized in that: In step 4, the hydrated oxide layer on the surface of the tungsten oxide electrode is protonated, and the potential of the tungsten oxide electrode will drift negatively in the flowing liquid, indicating that the potential change of the tungsten oxide electrode in the flowing liquid is generated by the flow potential.

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