Sampling detection method and sampling detection device for soil remediation

Abstract

The invention relates to the technical field of soil remediation sampling detection, in particular to a sampling detection method and a sampling detection device for soil remediation, and the sampling detection method and the sampling detection device are specifically characterized in that based on the difference between the heating temperature of inert gas and the initial soil temperature and the accumulated difference between the soil temperature and the heating temperature in the thermal desorption process, the temperature of the inert gas is calculated; and calculating the desorption effect deviation of the gas in the soil, calculating the peak shape distortion coefficient of each chromatographic peak based on the symmetry of each chromatographic peak in the gas chromatogram, and correcting the area of each chromatographic peak in combination with the fluctuation condition of the gas pressure data to obtain the gas desorption effect deviation of the gas in the soil. The problem of possible deviation between the detection result and the actual condition due to the fact that the concentration component of the mixed gas is directly measured based on the chromatographic peak area in a gas chromatogram in a traditional mode is solved, and when the gas in the soil is detected, the gas detection precision is improved, and the accurate acquisition of various pollution data in the soil remediation process is facilitated.

Description

Technical Field

[0001] This application relates to the technical field of soil remediation sampling and detection, and specifically relates to a sampling and detection method and a sampling and detection device for soil remediation. Background Art

[0002] For contaminated soil, soil remediation is carried out, that is, by using physical, chemical, and biological methods, the content of pollutants in the soil is reduced through transfer, absorption, degradation, and transformation to achieve the soil remediation effect. In the current soil remediation process, it is basically divided into in-situ remediation and ex-situ remediation. Regardless of which remediation method is used, the remediation effect of the soil needs to be detected. The sampling of soil remediation mainly uses manual dug-hole sampling, with a long detection period and low efficiency.

[0003] In the traditional soil gas detection method, the collected gas is directly transmitted to the detection device, ignoring the influence of the differences in the formation environment changes on the detection. During the actual measurement process, due to the differences in soil geological conditions and environmental changes, there will be differences in the thermal desorption of the soil, and waveform distortion will occur in the chromatogram. As a result, there is a deviation between the traditional measurement method and the content of volatile organic gases in the actual remediated soil, reducing the detection accuracy of the soil remediation effect. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a sampling and detection method and a sampling and detection device for soil remediation. The specific technical solutions adopted are as follows: In the first aspect, an embodiment of this application provides a sampling and detection method for soil remediation, and the method includes the following steps: Obtain the volatile organic gases of the remediated soil through thermal desorption in the sampling pipeline, and obtain the gas chromatogram, the temperature data of the soil at each moment, and the air pressure data in the sampling pipeline; Obtain the heating temperature of the inert gas used for thermal desorption; calculate the desorption effect deviation of the gas in the soil based on the difference between the heating temperature of the inert gas and the initial soil temperature, and the cumulative difference between the soil temperature and the heating temperature during the thermal desorption process; Calculate the peak shape distortion coefficient of each chromatographic peak based on the symmetry of each chromatographic peak in the gas chromatogram; Based on the desorption effect deviation and the peak shape distortion coefficient, and combined with the fluctuation of the air pressure data, correct the area of each chromatographic peak; Detect the gas component types and concentrations in the soil by combining the corrected chromatographic peak area and the position of each chromatographic peak in the chromatogram, and using the external standard method.

[0005] In one of the embodiments, the process of obtaining the desorption effect deviation of the gas in the soil is as follows: The deviation of the desorption effect of the gas in the soil is denoted as A, and the expression of A is: , where represents the temperature difference between the heating temperature of the inert gas and the initial soil temperature; and represent the initial moment and the end moment of the thermal desorption process respectively; represents the heating temperature of the inert gas; represents the fitting function of the soil temperature with respect to time; is the normalization function.

[0006] In one embodiment, the fitting function of the soil temperature with respect to time is: the fitting function obtained by fitting all temperature data through a curve fitting algorithm.

[0007] In one embodiment, the process of obtaining the peak shape distortion coefficient of each chromatographic peak is: Obtain the peak interval and peak point of each chromatographic peak in the gas chromatogram; calculate the similarity between the data on the left and right sides of the peak point in each peak interval, denoted as the first similarity; based on the first similarity and the signal intensity difference between the left and right sides of the peak point in the peak interval, calculate the peak shape distortion coefficient of the chromatographic peak.

[0008] In one embodiment, the process of obtaining the peak interval and peak point of each chromatographic peak is: Obtain the baseline in the gas chromatogram by the moving average method, and use the peak detection algorithm to obtain each peak point in the gas chromatogram; determine the peak interval of the chromatographic peak based on the peak point and the baseline.

[0009] In one embodiment, the process of obtaining the peak interval is: Take the first point on the baseline to the left of each peak point as the left edge point of the corresponding peak interval, and take the first point on the baseline to the right of each peak point as the right edge point of the corresponding peak interval, to obtain the peak interval of each chromatographic peak where the peak point is located.

[0010] In one embodiment, the process of obtaining the first similarity is: the absolute value of the Pearson correlation coefficient between the data sequence on the left side of the peak point and the data sequence on the right side of the peak point in the peak interval.

[0011] In one embodiment, the expression of the peak shape distortion coefficient of the chromatographic peak is: where represents the peak shape distortion coefficient of the j-th chromatographic peak, represents the first similarity of the j-th chromatographic peak, is a preset extremely small positive number, represents the minimum value between the number of data points on the left side and the number of data points on the right side of the peak value point of the j-th chromatographic peak, and respectively represent the signal intensities of the i-th data point on the left side and the i-th data point on the right side of the peak value point of the j-th chromatographic peak, is the Sigmoid function.

[0012] In one embodiment, the correction of the area of each chromatographic peak is expressed as: In the formula, is the area of the j-th chromatographic peak after correction; is the area of the j-th chromatographic peak before correction; represents a preset scaling coefficient; A represents the deviation of the desorption effect of the gas in the soil; represents the peak shape distortion coefficient of the j-th chromatographic peak; represents the variance of all the air pressure data corresponding to the time window occupied by the j-th chromatographic peak; represents the normalization function.

[0013] In a second aspect, the embodiment of the present application further provides a sampling and detection device for soil remediation, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of the method described in any one of the above are implemented.

[0014] The embodiment of the present application has at least the following beneficial effects: Compared with the traditional method of batch sampling and fixed submission for inspection, the present solution can realize automatic sampling and dynamic detection, greatly improving the sampling and detection efficiency of soil remediation; based on the difference between the heating temperature of the inert gas and the initial soil temperature, and the cumulative difference between the soil temperature and the heating temperature during the thermal desorption process, the desorption effect deviation of the gas in the soil is calculated, and by analyzing the soil temperature diffusion situation, the problem of inaccurate gas detection results caused by poor volatility of organic gases during the thermal desorption process is avoided; based on the symmetry of each chromatographic peak in the gas chromatogram, the peak shape distortion coefficient of each chromatographic peak is calculated, and the influence of gas chromatographic data distortion on the measurement result is analyzed; combined with the fluctuation of the air pressure data, the area of each chromatographic peak is corrected, avoiding the problem that the detection result may deviate from the actual conditions when directly measuring the concentration components of the mixed gas based on the chromatographic peak area in the gas chromatogram in the traditional method. Furthermore, when detecting the gas in the soil, the gas detection accuracy is improved, facilitating the accurate collection of various pollution data during the soil remediation process. Description of the Drawings

[0015] To more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0016] Figure 1 It is a flowchart of the steps of a sampling and detection method for soil remediation provided by an embodiment of the present application; Figure 2 It is a schematic diagram of the acquisition process of the peak shape distortion coefficient. Detailed implementation manners

[0017] In order to further elaborate on the technical means and effects adopted by the present application to achieve the intended invention purpose, the following, in combination with the drawings and preferred embodiments, details the specific implementation manners, structures, features and effects of the sampling and detection method and sampling and detection device for soil remediation proposed according to the present application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0019] The following specifically describes the specific solutions of the sampling and detection method and sampling and detection device for soil remediation provided by the present application in conjunction with the drawings.

[0020] Please refer to Figure 1 , which shows a flowchart of the steps of a sampling and detection method for soil remediation provided by an embodiment of the present application. The method includes the following steps: Step S1, obtain the volatile organic gases of the remediated soil by thermal desorption in the sampling pipeline, obtain the gas chromatogram of the gas, the temperature data of the soil at each moment, and the air pressure data in the sampling pipeline.

[0021] The present application uses an environmental protection robot that can be used for gas detection in soil for sampling and detection. It can penetrate its sampling module deep into the soil layer through drilling. The volatile organic gases in the soil layer can penetrate into the sampling pipeline of the sampling module. Through the blowing of heated inert gas, the gas collected in the sampling pipeline can be transported to its detection module for gas chromatographic analysis, and the sampling of volatile gases in the soil is realized based on the principle of thermal desorption. The sampling module and the detection module are well-known technologies, and the specific process will not be elaborated here.

[0022] During the drilling process, differences in environmental changes that may exist in the soil are repaired, resulting in deviations in the measurement of volatile organic gases in the soil. In order to obtain the difference information of the soil, a temperature sensor is deployed at the top of the sampling module to collect the temperature data of the soil at each moment, and a pressure sensor is deployed inside the sampling pipeline to collect the pressure data inside the sampling pipeline at each moment.

[0023] In the embodiment of the present application, a gas chromatograph is used to detect volatile organic gases in the soil. The chromatographic conditions for gas data analysis using the chromatograph are set as follows: the carrier gas is a high-purity (99.99%) inert gas, which is the same as the sweeping inert gas, and the flow rate is set to 0.2 ml / min; the temperature of the switching valve is set to 50 °C; the desorption temperature of the adsorption tube is 300 °C; the temperature of the gas chromatograph interface and the injection port is 150 °C; the split ratio is set to 100:1; the temperature increase of the chromatographic column is set to maintain at 50 °C for 1 min; it is heated to 90 °C at a rate of 20 °C / min, and then heated to 220 °C at a rate of 65 °C / min and maintained for 1 min. At the same time, the retention time of the entire gas chromatograph is 30 - 40 min, which is the same as the thermal desorption duration. As other embodiments of the present application, implementers can use other methods to detect volatile organic gases in the soil according to actual situations.

[0024] In the gas chromatogram obtained by the gas chromatograph, the abscissa represents time, and the ordinate represents the signal intensity, in mV units. During the thermal desorption process of the repaired soil, the sampled gas contains a mixed gas composed of an inert gas and pollutant volatile organic gases. The pollutant volatile organic gases refer to alkanes, aromatics, alkenes, halogenated hydrocarbons, esters, aldehydes, ketones, etc. According to the different interactions between the mixed gas and the stationary phase in the gas chromatograph, the moving speeds of different gases on the chromatographic column are different, so different retention times are presented. And the presentation method on the chromatogram is that each gas will present a chromatographic peak, and the higher the content of the gas, the higher the corresponding chromatographic peak.

[0025] Step S2, obtain the heating temperature of the inert gas for thermal desorption; based on the difference between the heating temperature of the inert gas and the initial soil temperature, and the cumulative difference between the soil temperature and the heating temperature during the thermal desorption process, calculate the desorption effect deviation of the gas in the soil.

[0026] In the traditional detection method, the content of a single volatile organic gas is obtained by comparing the detected chromatographic peak area with a standard. During the actual measurement process, due to differences in soil geological conditions and environmental changes, there will be differences in the thermal desorption of the soil, and waveform distortion will occur in the chromatogram. As a result, there is a deviation between the traditional measurement method and the actual content of volatile organic gases in the repaired soil, reducing the detection accuracy of the soil repair effect.

[0027] During the thermal desorption process, the geological conditions of the soil are the key influencing factors affecting thermal desorption. During the thermal desorption process, by sweeping and blowing high-temperature inert gas, the temperature of the soil layer contacted by the membrane interface detector is gradually increased, resulting in the volatile organic gases adsorbed by the soil particles becoming free state, being able to pass through the semi-permeable membrane of the membrane interface detector, and being collected by the sampling device. It is thus considered that when the soil is passively heated to the temperature of the high-temperature inert gas, the thermal desorption effect is the best.

[0028] However, in the actual process, affected by the initial geological temperature of the soil and the temperature diffusion situation, the volatility of organic gases during the thermal desorption process is poor, showing a deviation from the content of volatile gases in the actual soil. Thus, based on the entire thermal desorption process, if the initial temperature of the soil is higher, it is more conducive to the thermal desorption and volatilization of gases in the soil. In addition, if the soil heats up faster, it indicates that the temperature transfer effect in the soil is better, facilitating more organic gases in the soil layer contacted by the membrane interface detector to desorb from the soil particles.

[0029] Thus, combining the above analysis, a desorption effect evaluation is constructed, and the expression is: , where A represents the deviation of the desorption effect of the gas in the soil at the current sampling point position; represents the temperature difference between the temperature of the heated inert gas and the soil temperature at the initial moment. The heating temperature of the inert gas is generally 110°C to 120°C. In the embodiments of the present application, the heating temperature of the inert gas is set to 120°C; and respectively represent the initial moment and the end moment of the thermal desorption process, and the time unit is minutes; represents the set heating temperature of the inert gas; represents the fitting function of the soil temperature with respect to time; is a normalization function. In the embodiments of the present application, the unit of all types of temperature data is degrees Celsius. Here, the normalization function used in the present application is the Sigmoid function. It can be understood that the normalization function only takes the numerical value and does not include the units of the respective independent variables in the formula. For example, when normalizing , assuming has a value of 100°C, then the numerical value 100 is substituted into the Sigmoid function for calculation. After rounding to three decimal places in the calculation result, the calculated result 1.000 is the result of , and this result is only a numerical value without a unit. The calculation result of is the same, only a numerical value without a unit. It should be noted that there are many existing normalization methods, and the implementer can also use other normalization methods for normalization, which is not specifically limited in the present application.

[0030] Among them, the process of obtaining the fitting function of the soil temperature with respect to time can be as follows: Obtain the time series of the soil temperature data collected by the temperature sensor, fit the time series by the least squares method, and use the obtained fitting function as the fitting function of the soil temperature with respect to time. Among them, the least squares method is a well-known technology, and the specific process will not be elaborated. It should be noted that for the curve fitting of the soil temperature time series, this application only provides a curve fitting method. There are many existing curve fitting methods, and implementers can also use other curve fitting methods to perform curve fitting on the soil temperature time series. This application does not make specific restrictions.

[0031] The higher the initial temperature of the soil, the lower the temperature difference from the inert gas, and the faster the soil temperature rises, indicating that the desorption effect of the soil is better, and the deviation of the desorption effect will be smaller.

[0032] Step S3, calculate the peak shape distortion coefficient of each chromatographic peak based on the symmetry of each chromatographic peak in the gas chromatogram.

[0033] When performing gas chromatography detection on the volatile organic gases sampled from the repaired soil, since the detection is carried out on the mobile detection platform of the soil repair sampling detection device, it is easily affected by the external environmental interference, resulting in distortion of the collected gas chromatogram, and there is a deviation from the repair effect of the soil.

[0034] Ideally, in the gas chromatogram corresponding to the sampled mixed gas, each gas corresponds to a single sharp chromatographic peak, and the chromatographic peaks are basically symmetrically distributed. When affected by environmental interference and the chromatographic peak data is distorted, there may be a situation of peak tailing or peak extension. When the chromatographic peak is distorted, there will be some false areas, thereby affecting the measurement of the concentration of the single gas corresponding to the chromatographic peak in the sampled mixed gas.

[0035] In the gas chromatogram of the mixed gas, there are multiple chromatographic peaks (corresponding to the respective gas components in the mixed gas) and baseline information, and the multiple chromatographic peaks are segmented by baseline segments. Therefore, it is first necessary to obtain the baseline according to the data in the gas chromatogram. In this application, the baseline in the chromatogram is obtained by the moving average method. At the same time, for the data in the gas chromatogram, a peak detection algorithm is used to obtain each peak point in the gas chromatogram. The point on the baseline to the left of each peak point is used as the left edge point of the corresponding peak interval, and the point on the baseline to the right of each peak point is used as the right edge point of the corresponding peak interval, so as to obtain the peak intervals of the chromatographic peaks where each peak point is located. Among them, if two peaks are connected, that is, there is no point on the baseline between the two peaks, the minimum value point between the two peak points is used as the demarcation point of the two peak intervals. It should be noted that for the acquisition of the peak interval, this application only provides one way to obtain the peak interval. There are many existing methods to obtain the peak interval, and implementers can also use other methods to obtain the peak interval. This application does not make specific restrictions.

[0036] Among them, the process of obtaining the baseline by the moving average method and the peak detection algorithm are both well-known technologies, and the specific process will not be elaborated. It should be noted that for the acquisition of the baseline and peak points, this application only provides one acquisition method. There are many existing methods to obtain the baseline and peak points, and implementers can also use other corresponding algorithms to obtain the baseline and peak points respectively. This application does not make specific restrictions.

[0037] For a single chromatographic peak, in the peak interval of the chromatographic peak, calculate the absolute value of the Pearson correlation coefficient between the data sequence on the left side of the peak point and the data sequence on the right side of the peak point as the similarity between the data on the left and right sides of the peak point, denoted as the first similarity. Among them, the Pearson correlation coefficient is a well-known technology, and the specific process will not be elaborated.

[0038] It can be understood that for the calculation of the first similarity, this application only provides one similarity calculation method. There are many existing methods to calculate similarity, and implementers can also use other similarity algorithms to calculate the first similarity. This application does not make specific restrictions. It should be noted that if the lengths of the data on the left and right sides for calculating the similarity measure are inconsistent, the processing method is to fill in the data on the side with fewer numbers by linear interpolation and then perform the similarity calculation.

[0039] Therefore, based on the above analysis, the peak shape distortion coefficient of a single chromatographic peak is constructed, and the expression is: In the formula, represents the peak shape distortion coefficient of the j-th chromatographic peak in the gas chromatogram of the mixed gas collected at the current sampling point, represents the first similarity of the j-th chromatographic peak, is a preset extremely small positive number, represents the minimum value between the number of data points on the left side and the number of data points on the right side of the peak point of the j-th chromatographic peak, and respectively represent the signal intensities of the i-th data point on the left side and the i-th data point on the right side of the peak point of the j-th chromatographic peak, is the Sigmoid function. Among them, the time intervals from the i-th data point on the left side of the peak point and the i-th data point on the right side of the peak point to the peak point are equal. The role of is to prevent the denominator from being 0. Preferably, in the embodiments of the present application, is set to 0.01. As other embodiments of the present application, the implementer can set it according to the actual situation. Among them, the unit of the signal intensity of the data point is millivolt (mV). It can be understood that the Sigmoid function only takes numerical values and does not include the units of the respective independent variables in the formula. For example, assuming the calculation result of is 5 mV, then the numerical value 5 is brought into the Sigmoid function for calculation. When the calculation result is reserved to three decimal places, rounding is performed, and the obtained calculation result is 0.993. This result is only a numerical value and has no unit. It should be noted that there are many existing normalization methods, and the implementer can also use other normalization methods for normalization. The present application does not make specific limitations.

[0040] The smaller the interference situation of the current chromatographic peak, the higher the symmetry of the obtained chromatographic peak. Therefore, the data similarity of the left and right sides of the current chromatographic peak divided by the peak point is higher. At the same time, the smaller the signal intensity difference at the position points symmetric about the peak point in terms of distance on the left and right sides. Therefore, the smaller the difference in the distortion situation of the peak shape.

[0041] Step S4, based on the desorption effect deviation and the peak shape distortion coefficient, combined with the fluctuation situation of the air pressure data, correct the area of each chromatographic peak.

[0042] When calculating the gas concentration according to the chromatographic peak, it mainly depends on the area of the chromatographic peak. Therefore, it is necessary to correct the area of the chromatographic peak according to the external environment situation and the distortion situation of the chromatographic peak, and construct a component correction model. The corrected area of each chromatographic peak is: In the formula, is the corrected area of the j-th chromatographic peak; is the area of the j-th chromatographic peak before correction; represents a preset scaling coefficient. Preferably, in the embodiments of the present application, is set to 1.5; A represents the desorption effect deviation of the gas in the soil at the current sampling point position; represents the peak shape distortion coefficient of the j-th chromatographic peak; It represents the variance of all air pressure data corresponding to the time window occupied by the j-th chromatographic peak; It represents a normalization function. Among them, the acquisition of the area of the chromatographic peak before correction is a well-known technology, and the specific process will not be elaborated here. Among them Its function is: Since the normalized value is between 0 and 1, if the normalized value is directly used, only the area of the chromatographic peak can be reduced. By the scaling factor, the problem of only being able to reduce and correct can be avoided. The value range of is 1 to 2. As other embodiments of the present application, the implementer can set the value according to the actual situation by himself. Among them, the area unit of the chromatographic peak is mV·s. The normalization function used in this application here is the maximum-minimum normalization method. It can be understood that the normalization function only takes the numerical value and does not include the units of the respective independent variables in the formula. For example, assume that the value of the j-th chromatographic peak at the current sampling point is 5, and the corresponding calculated values of other chromatographic peaks at other sampling points are 2, 2, 3, 3, 4, 6 respectively. Then the set {2, 2, 3, 3, 4, 6, 5} is used as the input of the maximum-minimum normalization method for normalization, and the normalized value 0.75 of the numerical value 5 obtained is the result, and this result is only a numerical value without a unit. It should be noted that there are many existing normalization methods, and the implementer can also use other normalization methods for normalization, and this application does not make specific restrictions.

[0043] In the component correction model, first consider the geological conditions in the environment. If the current soil geological conditions are worse, it may make the desorption effect of volatile organic gases in the soil poor. At this time, the concentration of the sampled mixed gas is relatively smaller than the actual soil situation. At the same time, consider the morphological distribution of a single chromatographic peak. If the distortion of the chromatographic peak is more serious, it indicates that the interference is greater. At this time, it may be manifested as a front or tail phenomenon on the waveform, making the measured peak area larger than the actual situation. In addition, combine the air pressure situation in the sampling pipeline during the time period corresponding to the chromatographic peak. Since the sampling pipeline is directly connected to the chromatograph, if the air pressure fluctuates, it will affect the distribution of the chromatographic peak and may further cause the chromatographic peak to be distorted.

[0044] Based on the above analysis, a component correction model is constructed to correct the peak area of each chromatographic peak, and thus the chromatographic peak area close to the actual soil situation of each chromatographic peak is obtained, which is convenient for accurately collecting various pollution data during the soil remediation process.

[0045] Step S5, through the corrected chromatographic peak area and the position of each chromatographic peak in the chromatogram, combined with the external standard method, detect the types and concentrations of gas components in the soil.

[0046] By obtaining the nearly true chromatographic peak areas of various components in the sampled mixed gas, the external standard method is adopted in this solution to obtain the category and concentration information of various gas components in the soil at the current sampling point. Specifically, under the same chromatographic conditions as the gas to be measured, the chromatograms of standard gas samples with different concentrations are measured, and the chromatogram data of all standard gas samples at all concentrations are combined to form a database; the peak areas of known-concentration standard single-component gases under the same conditions are obtained from the database for quantification, and the concentration of the component corresponding to the chromatographic peak is obtained by combining the chromatographic peak area after sampling correction and the calibration peak area. At the same time, in combination with the position where the sampling chromatographic peak appears, the category corresponding to the volatile gas is determined by comparing the position of the standard gas in the chromatogram. The external standard method is a well-known technology, and the specific process will not be elaborated here.

[0047] Based on the sampling detection and analysis, the category and concentration information of various components in the volatile organic gases of the soil to be repaired at the current sampling point are obtained.

[0048] The schematic diagram of the acquisition process of the peak shape distortion coefficient is as Figure 2 shown.

[0049] Based on the same inventive concept as the above method, the embodiment of the present application also provides a sampling detection device for soil remediation, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of any one of the above sampling detection methods for soil remediation are implemented.

[0050] In summary, the embodiment of the present application provides a sampling detection method for soil remediation. Compared with the traditional method of batch sampling and fixed submission for inspection, this solution can realize automatic sampling and dynamic detection, greatly improving the sampling detection efficiency of soil remediation; based on the difference between the heating temperature of the inert gas and the initial soil temperature, and the cumulative difference between the soil temperature and the heating temperature during the thermal desorption process, the desorption effect deviation of the gas in the soil is calculated, and by analyzing the soil temperature diffusion situation, the problem of inaccurate gas detection results caused by poor volatility of organic gases during the thermal desorption process is avoided; based on the symmetry of each chromatographic peak in the gas chromatogram, the peak shape distortion coefficient of each chromatographic peak is calculated, and the influence of the distortion of the gas chromatographic data on the measurement result is analyzed; in combination with the fluctuation of the air pressure data, the area of each chromatographic peak is corrected, avoiding the problem that the detection result may deviate from the actual conditions when the concentration components of the mixed gas are directly determined based on the chromatographic peak area in the gas chromatogram in the traditional method. Furthermore, when detecting the gas in the soil, the gas detection accuracy is improved, which is convenient for accurately collecting various pollution data during the soil remediation process.

[0051] It should be noted that the above order of the embodiments of the present application is only for description and does not represent the superiority or inferiority of the embodiments. In addition, the above specific embodiments of the present application have been described. Further, the processes depicted in the accompanying drawings do not necessarily require the particular order or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0052] Each embodiment in the present application is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the key point of each embodiment is to illustrate the differences from other embodiments.

[0053] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the principle of the present application shall be included within the protection scope of the present application.

Claims

1. A sampling and detection method for soil remediation, characterized in that, The method includes the following steps: Obtain the volatile organic gases of the repaired soil through thermal desorption in the sampling pipeline, obtain the gas chromatogram, the temperature data of the soil at each moment, and the air pressure data in the sampling pipeline; Obtain the heating temperature of the inert gas for thermal desorption; calculate the desorption effect deviation of the gas in the soil based on the difference between the heating temperature of the inert gas and the initial soil temperature, and the cumulative difference between the soil temperature and the heating temperature during the thermal desorption process; Calculate the peak shape distortion coefficient of each chromatographic peak based on the symmetry of each chromatographic peak in the gas chromatogram; Based on the desorption effect deviation and the peak shape distortion coefficient, and in combination with the fluctuation of the air pressure data, correct the area of each chromatographic peak; Detect the gas component categories and concentrations in the soil by combining the corrected chromatographic peak area and the position of each chromatographic peak in the chromatogram with the external standard method.

2. The sampling and detection method for soil remediation according to claim 1, wherein The process of obtaining the desorption effect deviation of the gas in the soil is as follows: Record the desorption effect deviation of the gas in the soil as A, and the expression of A is: , where represents the temperature difference between the heating temperature of the inert gas and the initial soil temperature; and represent the initial moment and the ending moment of the thermal desorption process, respectively; represents the heating temperature of the inert gas; represents the fitting function of the soil temperature with respect to time; is a normalization function.

3. The sampling and detection method for soil remediation according to claim 2, wherein The fitting function of the soil temperature with respect to time is: the fitting function obtained by fitting all temperature data through the curve fitting algorithm.

4. The sampling and detection method for soil remediation according to claim 1, wherein The process of obtaining the peak shape distortion coefficient of each chromatographic peak is as follows: Obtain the peak interval and peak point of each chromatographic peak in the gas chromatogram; calculate the similarity between the data on the left and right sides of the peak point in each peak interval, which is recorded as the first similarity; calculate the peak shape distortion coefficient of the chromatographic peak based on the first similarity and the signal intensity difference between the left and right sides of the peak point in the peak interval.

5. The sampling and detection method for soil remediation according to claim 4, characterized in that The process of obtaining the peak interval and peak point of each chromatographic peak is as follows: Obtain the baseline in the gas chromatogram by the moving average method, and obtain each peak point in the gas chromatogram by the peak detection algorithm; determine the peak interval of the chromatographic peak based on the peak point and the baseline.

6. The sampling and detection method for soil remediation according to claim 5, characterized in that, The process of obtaining the peak interval is as follows: Take the first point on the baseline to the left of each peak point as the left edge point of the corresponding peak interval, and take the first point on the baseline to the right of each peak point as the right edge point of the corresponding peak interval, so as to obtain the peak interval of each chromatographic peak where the peak point is located.

7. The sampling and detection method for soil remediation according to claim 4, wherein, The process of obtaining the first similarity is: the absolute value of the Pearson correlation coefficient between the data sequence on the left side of the peak point and the data sequence on the right side of the peak point in the peak interval.

8. The sampling and detection method for soil remediation according to claim 4, characterized in that, The expression of the peak shape distortion coefficient of the chromatographic peak is: In the formula, represents the peak shape distortion coefficient of the j-th chromatographic peak, represents the first similarity of the j-th chromatographic peak, is a preset extremely small positive number, represents the minimum value of the number of data points on the left side and the number of data points on the right side of the peak value point of the j-th chromatographic peak, and respectively represent the signal intensities of the i-th data point on the left side and the i-th data point on the right side of the peak value point of the j-th chromatographic peak, is the Sigmoid function.

9. The sampling and detection method for soil remediation according to claim 1, wherein The expression for correcting the area of each chromatographic peak is: In the formula, is the area of the j-th chromatographic peak after correction; is the area of the j-th chromatographic peak before correction; represents the preset scaling coefficient; A represents the deviation of the desorption effect of the gas in the soil; represents the peak shape distortion coefficient of the j-th chromatographic peak; represents the variance of all the barometric data corresponding to the time window occupied by the j-th chromatographic peak; represents the normalization function.

10. A sampling and detection device for soil remediation, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1-9.

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