Water environment heavy metal pollution measuring method based on electrochemical analysis

Abstract

The invention provides a water environment heavy metal pollution measuring method based on electrochemical analysis. The method comprises the following steps: constructing a linear coefficient comparison set and a constant term comparison set of peak current and concentration of heavy metal ions on a certain stripping volt-ampere peak potential by aiming at different samples in a water environment detected sample set of a certain heavy metal; and then, by constructing a water environment similar sample set of the to-be-measured sample for heavy metal pollution measurement, the measurement concentration of the to-be-measured sample about the heavy metal ions is given. According to the technical scheme provided by the invention, the to-be-detected water environment sample is matched according to the data of a certain heavy metal ion of the detected water environment sample in the past, so that the adaptability of rapidly detecting the heavy metal ions of different water environment samples through the electrochemical detection device is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of measurement-related technologies that are not specific to a particular variable, and in particular relates to a method for measuring heavy metal pollution in aquatic environments based on electrochemical analysis. Background Technology

[0002] Heavy metal pollution is one of the most serious environmental problems in water pollution. These heavy metals are persistent, bioaccumulative, and highly toxic; even trace amounts can pose a serious threat to ecosystems and human health. Heavy metals possess unique physicochemical properties. They are not biodegradable and exist in water bodies in ionic form for extended periods. Some heavy metals can be transformed into more toxic forms under the action of microorganisms, such as inorganic mercury transforming into methylmercury. Heavy metal pollution is insidious and cumulative. They are colorless and odorless, making them difficult to detect, but they can amplify step by step through the food chain.

[0003] Currently, the main analytical methods for detecting heavy metals include atomic absorption spectrometry, atomic fluorescence spectrometry, ultraviolet-visible spectrophotometry, and electrochemical analysis. Electrochemical analysis offers advantages such as reliability, portability, and low cost, and is widely used in safety monitoring, environmental assessment, and clinical diagnosis for the quantitative detection of metal ions, providing a technological foundation for rapid real-time detection. Stripping voltammetry is a common electrochemical analytical method. It typically uses a three-electrode system, including a working electrode, a reference electrode, and a counter electrode. This method consists of two steps: electrolytic enrichment and electrolytic dissolution. In the initial detection phase, the analyte is enriched onto the electrode surface through electrolytic deposition, followed by electrolytic dissolution. Since the dissolution peak potential is related to the half-wave potential of the analyte, and different substances have different half-wave potentials, multiple ions in solution can be detected simultaneously. Stripping voltammetry is further classified into cathodic stripping voltammetry and anodic stripping voltammetry based on whether the working electrode acts as the cathode or anode during dissolution. It can also be classified into differential pulse stripping voltammetry, square wave pulse stripping voltammetry, and cyclic voltammetry based on the waveform.

[0004] Differential pulse stripping voltammetry (PPV) is currently a highly sensitive method with a low detection limit in electrochemical detection and analysis. It involves sampling the current twice, before and at the end of the pulse, and calculating the current difference. The resulting current-to-voltage curve is the differential pulse stripping voltammetry curve. This method can largely eliminate background current noise from the charging and discharging of the electrode double layer in solution, significantly improving the signal-to-noise ratio and sensitivity. When detecting a specific heavy metal ion, the intensity of the peak current change at the stripping voltammetric peak reflects the concentration of the heavy metal ion. Therefore, a mathematical model with a linear quantitative relationship between the peak current and the concentration of the heavy metal ion can be established. Consequently, this method has wide applications in the rapid detection of heavy metal ions.

[0005] Considering that the concentrations of substances other than heavy metals vary in different aquatic environments, and consequently the intensity of these changes also differs, the single mathematical model constructed using differential pulse stripping voltammetry for rapid detection of heavy metal ions in aquatic environments is subject to stringent application conditions, particularly when there are significant differences in water composition. Therefore, when using electrochemical analysis to detect heavy metal pollution in aquatic environments, a method for rapid detection of heavy metal ions in different aquatic environments is needed. Summary of the Invention

[0006] To avoid the shortcomings of the existing technologies, this invention proposes a method for measuring heavy metal pollution in aquatic environments based on electrochemical analysis. By matching the peak current at the dissolution voltammetry peak position in the water sample to be tested with the intensity of the change in heavy metal ion concentration using previously measured water samples for a certain heavy metal ion, this method enhances the adaptability of different water samples to rapid detection of heavy metal ions using differential pulse dissolution voltammetry via electrochemical detection devices.

[0007] To achieve the above objectives, the technical solution of the present invention includes the following steps:

[0008] Step 1: When using differential pulse stripping voltammetry to perform electrochemical analysis and measurement of heavy metal pollution in aquatic environments, the linear coefficients and constant terms of the peak current and concentration of different samples in the set of measured samples of the heavy metal in the aquatic environment at different stripping voltammetric peak potentials are obtained. This allows for the construction of a set of comparisons of the linear coefficients and constant terms of the peak current and concentration of the heavy metal ion at a certain stripping voltammetric peak potential.

[0009] Step 2: After sampling the water environment for which heavy metal pollution measurement is required, the sample to be tested is divided into two parts. One part is left to stand and remain unchanged, while the other part is output through a reverse osmosis membrane. The peak current obtained by repeatedly testing the two types of samples at a certain dissolution voltammetric peak potential corresponding to a certain heavy metal is used to construct the original state peak current value set and the purified state peak current value set of the sampled samples with respect to the heavy metal ion at the dissolution voltammetric peak potential. The similarity probability of the constant terms of peak current and concentration of the sampled samples with respect to the heavy metal ion at each dissolution voltammetric peak potential is used to determine the similarity probability of the sampled samples with respect to the heavy metal ion between the sampled samples and the sample to be tested with respect to the heavy metal ion at each dissolution voltammetric peak potential.

[0010] Step 3: By setting a sample similarity threshold for heavy metal pollution measurement in the water environment, a set of similar water environment samples for the heavy metal pollution measurement of the sample to be tested in Step 2 can be constructed, thereby giving the measured concentration of the heavy metal ion of the sample to be tested.

[0011] Furthermore, the specific steps of step 1 are as follows:

[0012] In the technical solution of this invention, when using differential pulse stripping voltammetry for electrochemical analysis of heavy metal ions in the aquatic environment, the three-electrode system and detection parameter settings are consistent. After sampling a certain aquatic environment, the sample number can be assigned as follows: ,set up For the sample Add the Sub-heavy metals After ion standard concentration solution, the dissolution voltammetric peak potential The above is the first The dissolution peak current (unit: ) obtained from repeated tests ),set up For the sample Add the Sub-heavy metals Heavy metals were determined in a laboratory setting after using a concentrated ion standard solution. The instrumental concentration of the ions (in units) ),in, It serves as an identifier for heavy metal ions, and , This refers to the collection of heavy metal ions that need to be monitored in the aquatic environment. This is used to identify the dissolution voltammetric peak potential. For quantitative analysis using differential pulse stripping voltammetry The set of leaching voltammetric peak potentials for a certain heavy metal For ions, the stripping voltammetric peak potential used It should belong to , For the sample Adding heavy metals The serial number of the ion standard concentrate. It can be known that A value of 0 indicates that no addition has been made. This refers to the maximum number of times heavy metal standard concentrations can be added to samples from the aquatic environment. This represents the sequence number of times the water environment sample was repeatedly tested. , This represents the maximum number of times a sample can be repeatedly tested.

[0013] set up For the sample dissolution voltammetric peak potential Measuring heavy metals The linear coefficient between peak current and concentration. For the sample dissolution voltammetric peak potential Measuring heavy metals The constant term of peak current versus concentration, for any sample The time mentioned and The following first objective function must be satisfied. Specifically, it is expressed as:

[0014] in, To count the number of elements in a set; when as well as At that time, there exists Thus, the aforementioned and stated for: ,

[0015] This allows for the construction of heavy metals. Ions at dissolution voltammetric peak potential A comparison of the linear coefficients of peak current and concentration Comparison set with constant term They are respectively:

[0016] in, For heavy metals A collection of water environment samples has been measured.

[0017] Furthermore, the specific steps of step 2 are as follows:

[0018] To measure heavy metal pollution in a water environment, samples will be taken. It is divided into two parts. One part remains unchanged after standing, and the other part is output through a reverse osmosis membrane. and These are the sample labels: those that remain unchanged after standing and those that are output through the reverse osmosis membrane, respectively. and For the samples respectively and samples In heavy metals Corresponding stripping voltammetric peak potential The above is the first The dissolution peak current (unit: ) obtained from repeated tests ), thereby constructing a system for the test sample Regarding heavy metals Ions at dissolution voltammetric peak potential The original peak current value set on And the set of peak current values ​​for purification status They are respectively:

[0019] From the above and as described in step 1 The setup steps described in step 1 Included samples With the sample to be tested Regarding heavy metals Ions at dissolution voltammetric peak potential The similarity probability of the peak current and the constant term of concentration for:

[0020] in, and These are functions that select the minimum and maximum elements in a set, respectively.

[0021] Therefore, it can be determined that... Included samples With the sample to be tested Regarding heavy metals The similarity probability of ions is ; in, A function to calculate the number of elements in a set;

[0022] Furthermore, the specific steps of step 3 are as follows:

[0023] set up This serves as a sample similarity threshold for measuring heavy metal pollution in aquatic environments, from which the sample to be tested can be constructed. Heavy metals A collection of similar water environment samples for pollution measurement for:

[0024] Therefore, the following can be given regarding step 2: heavy metals Ion concentration measurement (Unit is) )for:

[0025] This completes the analysis of the water environment samples to be tested. heavy metals Pollution measurement.

[0026] Compared with existing technologies, the significant advancement of this invention lies in analyzing the similarity probability of a certain heavy metal ion between the tested water environment sample and the sample to be tested. Then, by using the linear quantitative relationship between the heavy metal ion concentration and the peak current at the dissolution voltammetry peak potential of multiple samples in a set of similar water environment samples for measuring the heavy metal pollution in the sample to be tested, the concentration of that heavy metal ion in the water environment sample to be tested is comprehensively evaluated. Based on the existing linear quantitative relationship model between the peak current change intensity at the dissolution voltammetry peak position of a certain heavy metal ion and its concentration, a comprehensive evaluation is performed to achieve rapid detection of heavy metal ions in different water environments. This provides a technical guarantee for the safe detection of water environments with advantages such as reliability, real-time performance, and low cost. Attached Figure Description

[0027] The accompanying drawings are defined as part of this invention and are used to provide a further understanding of the invention.

[0028] Figure 1 This is a schematic flowchart of a water environment heavy metal pollution measurement method based on electrochemical analysis, as described in an embodiment of the present invention.

[0029] Figure 2 This refers to the linear coefficient of peak current versus concentration when measuring heavy metal 82 at the 38th dissolution voltammetric peak potential for different samples in this embodiment of the invention.

[0030] Figure 3 This is a constant term representing the peak current and concentration of heavy metal 82 when different samples are measured at the 38th dissolution voltammetric peak potential in the embodiments of the present invention.

[0031] Figure 4 The dissolution peak current values ​​are obtained by repeating the tests three times on the dissolution voltammetric peak potential corresponding to heavy metal No. 82 and the sample that remained unchanged after standing in the embodiment of the present invention and the sample output through the reverse osmosis membrane. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific examples. The described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other equivalent or obvious modifications of the embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0033] This embodiment uses differential pulse stripping voltammetry for electrochemical analysis to measure lead pollution in a certain water environment. Figure 1 The flowchart illustrates a method for measuring heavy metal pollution in aquatic environments based on electrochemical analysis, as proposed in this invention. The specific steps are as follows:

[0034] Step 1: The differential pulse stripping voltammetry method is used in the technical solution of this invention to detect lead ions in the aquatic environment (…). When performing electrochemical analysis, the enrichment potential and enrichment time in the detection parameters of the electrochemical workstation are as follows: and The resting potential and resting time are respectively and The scan start potential and scan end potential are respectively and The pulse width and pulse period are respectively and The potential increment and amplitude are respectively and In the three-electrode system, silver is used as both the working electrode and the reference electrode. The three-electrode system and detection parameter settings are consistent. Assume the set of heavy metal ions to be detected in the aquatic environment is... for , can be set Ion labeling The metal is designated as 82, and is referred to as heavy metal No. 82. Quantitative analysis was performed using differential pulse stripping voltammetry. Collection of dissolution voltammetric peak potentials of the content for It is possible to set an indicator for the dissolution voltammetric peak potential. The value is 38, which can be referred to as the 38th dissolution voltammetric peak potential; the sample set tested in the aquatic environment for heavy metals 82. If the number of elements in the middle is 10, it can be represented as Among them, after sampling the water environment, the sample number can be set as follows: Set the maximum number of times heavy metal standard solution No. 82 is added to samples from the aquatic environment. The concentration is set to 4, and the concentration is increased by 3 each time after adding heavy metal standard solution No. 82. The maximum number of times a sample can be repeatedly tested. The value is 3, from which the sample can be measured. Add the After the second application of heavy metal ion standard solution No. 82, the third application was performed at the dissolution voltammetric potential No. 38. The dissolution peak current obtained from repeated tests (Unit is) ) and the samples Add the After obtaining the standard concentration of heavy metal ion No. 82 in a laboratory setting, the instrument-measured concentration of heavy metal ion No. 82 was determined. (Unit is) ),in, For the sample The sequence number of times the No. 82 heavy metal ion standard concentrate was added. , This represents the sequence number of times the water environment sample was repeatedly tested. ;set up Figure 2 and Figure 3 The text provides different samples. The linear coefficient of peak current versus concentration when measuring heavy metal 82 at the dissolution voltammetric peak potential No. 38. and constant term Therefore, a set of linear coefficients comparing the peak current and concentration of heavy metal ion No. 82 at the dissolution voltammetric peak potential No. 38 can be constructed. Comparison set with constant term ;

[0035] Step 2: Set up a sampling point for the water environment where heavy metal pollution measurements will be performed. The sample to be tested can be... The sample is divided into two parts: one part remains unchanged after standing, and the other part is output through a reverse osmosis membrane. The sample that remains unchanged after standing is labeled. and the labeling of samples output through reverse osmosis membrane They are 11 and 12 respectively; by measuring the effect on the samples respectively and samples The voltammetric peak potential corresponding to the 38th dissolution voltammetric peak of heavy metal No. 82 was used to perform the [further analysis]. The dissolution peak current obtained from repeated tests and (Unit is) ),in Specific values ​​are as follows Figure 4 As shown in the figure, this constructs a method for testing samples. A set of peak current values ​​for the original state of heavy metal ion No. 82 at the dissolution voltammetric peak potential No. 38. And the set of peak current values ​​for purification status ; Set the steps described in step 1 Included samples With the sample to be tested The probability of similarity between the peak current and concentration of heavy metal ion No. 82 at the dissolution voltammetric peak potential No. 38 is:

[0036] in, It is 82. It is 38. , It is 12. and These are functions that select the minimum and maximum elements in a set, respectively.

[0037] Therefore, it can be determined that... Included samples With the sample to be tested Similarity probability of heavy metal ion No. 82 for ;

[0038] Step 3: Set the sample similarity threshold for heavy metal pollution measurement in the water environment. The value is 0.9, from which the test sample can be constructed. A collection of similar water environment samples for measuring heavy metal pollution in area 82 for Regarding step 2 The measured concentration of heavy metal ion No. 82 for The lead concentration was 0.01 mg / L lower than the limit given in Table 1 of the national standard GB5749-2022 for conventional indicators and limits of drinking water quality. This completed the measurement of heavy metal pollution in the water environment based on electrochemical analysis.

[0039] All parts not explicitly stated in the above embodiments of the present invention can be implemented using existing technologies. The above embodiments of the present invention are merely illustrative of the technical solutions disclosed in the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical content of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for measuring heavy metal pollution in aquatic environments based on electrochemical analysis, characterized in that, Includes the following steps: Step 1: Construct a set of comparisons of linear coefficients and constant terms of peak current versus concentration for a certain heavy metal ion at a specific dissolution voltammetric peak potential using a set of water environment samples that have been tested for that heavy metal. Step 2: The water sample obtained from the water environment to be measured for heavy metal pollution is divided into two parts. One part is left to stand and remain unchanged as the original water environment sample to be measured. The other part is output through a reverse osmosis membrane as the purified water environment sample to be measured. Then, the set of peak current values ​​of the original state and the set of peak current values ​​of the purified state of the above-mentioned sample to be measured with respect to the dissolution voltammetric peak potential of the heavy metals mentioned in Step 1 are constructed. The similarity probability of each sample in the set of water environment samples tested for the above heavy metals with the sample to be tested regarding the above heavy metal ions is determined by comparing the constant terms of the peak current and concentration at the above dissolution voltammetry peak potential of the above heavy metal ions. Step 3: By constructing a set of similar water environment samples for the test samples described in Step 2 and measuring the heavy metal pollution in Step 1, the measured concentration of the heavy metal ions in the test samples is given.

2. The method for measuring heavy metal pollution in aquatic environments based on electrochemical analysis according to claim 1, characterized in that, The specific method for step 1 is as follows: set up For heavy metals The collected water environment samples can be obtained by sampling different water environments. For the identification of heavy metals, and This refers to a collection of heavy metals that need to be tested in the aquatic environment; let... For the sample Add the Sub-heavy metals After ion standard concentration solution, the dissolution voltammetric peak potential The above is the first The dissolution peak current obtained from repeated tests is set as follows: For the sample Add the Sub-heavy metals Heavy metals were determined in a laboratory setting after using a concentrated ion standard solution. The instrumental concentration corresponding to the ions was measured using differential pulse stripping voltammetry for electrochemical analysis of heavy metal ions in the aquatic environment. The three-electrode system and detection parameter settings were consistent throughout. The label for the water environment samples that have been tested. This is used to identify the dissolution voltammetric peak potential. For quantitative analysis using differential pulse stripping voltammetry The set of leaching voltammetric peak potentials for the above heavy metals. Ions, using stripping voltammetry peak potential belong For the water environment samples that have been tested Adding heavy metals The serial number of the ion standard concentrate. , A value of 0 indicates that no heavy metals have been added. This represents the maximum number of times heavy metals can be added. This represents the sequence number of the repeated tests. , This represents the maximum number of times the test can be repeated. set up For the water environment samples that have been tested dissolution voltammetric peak potential Measuring heavy metals The linear coefficient between peak current and concentration. For the water environment samples that have been tested dissolution voltammetric peak potential Measuring heavy metals The constant term of peak current versus concentration, for samples already measured in the aquatic environment. corresponding and The following first objective function must be satisfied. Specifically, it is expressed as: , in, To count the number of elements in a set; when as well as At that time, there exists Thus, the above is obtained and stated for: ， ， This leads to the construction of heavy metals Ions at dissolution voltammetric peak potential A comparison of the linear coefficients of peak current and concentration Comparison set with constant term They are respectively: ， 。 3. The method for measuring heavy metal pollution in aquatic environments based on electrochemical analysis according to claim 1, characterized in that, The specific method for step 2 is as follows: The water samples to be tested will be extracted from the aquatic environment where heavy metal pollution needs to be measured. , will the A portion of the sample remained unchanged after settling and was used as the original sample for water environment testing. Another portion of the water sample was passed through a reverse osmosis membrane and output as a water environment purification sample to be tested. ,in and These are the sample labels: those that remain unchanged after standing and those that are output through the reverse osmosis membrane, respectively. and Each of the above and stated In heavy metals Corresponding stripping voltammetric peak potential The above is the first The dissolution peak current obtained from repeated tests is used to construct the dissolution peak current for the aforementioned Regarding heavy metals Ions at dissolution voltammetric peak potential The original peak current value set on And the set of peak current values ​​for purification status They are respectively: ， From the above and as described in step 1 Set the Included water environment samples that have been tested With the Regarding heavy metals Ions at dissolution voltammetric peak potential The similarity probability of the peak current and the constant term of concentration for: , in, and These are functions that select the minimum and maximum elements in a set, respectively. Therefore, the above is determined. Included water environment samples that have been tested With the Regarding heavy metals The similarity probability of ions is ; in, This is a function to calculate the number of elements in a set.

4. The method for measuring heavy metal pollution in aquatic environments based on electrochemical analysis according to claim 1, characterized in that, The specific method for step 3 is as follows: set up This is a sample similarity threshold for measuring heavy metal pollution in the aquatic environment, thereby constructing the method described in step 2. Heavy metals A collection of similar water environment samples for pollution measurement for: ， Therefore, the above is given. heavy metals Ion concentration measurement for: ， in, , This completes the assessment of heavy metal pollution in the water environment as described in step 2, regarding heavy metals. Pollution measurement.

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