Online detection system and method for bisphenol A in water body

Abstract

The invention relates to the technical field of water body detection and analysis, in particular to an on-line detection system and method for bisphenol A in a water body, aiming at the characteristic that the chemical property of bisphenol A is obviously influenced by the pH value of the water body, the current pH value of the water body is detected on line, the state of bisphenol A in the current water body is determined, and if the bisphenol A is in a bisphenol A coexistence state, the bisphenol A in the water body is detected. If yes, the coupling correlation degree between the pH detection value of the water body and the bisphenol A ion proportion is analyzed, whether the problem is the detection precision problem of online detection equipment or the bisphenol A concentration detection problem influenced by the pH of the water body is distinguished, if the problem is the detection precision problem of the online detection equipment, parameter setting of the online detection equipment can be optimized in a targeted mode, and the detection accuracy of the bisphenol A concentration is improved. And the method can be used as reference data for predicting the state and concentration change trend of the bisphenol A, and can be used for predicting the optimal opportunity for online detection of the bisphenol A in the water body.

Description

Technical Field

[0001] This invention relates to the field of water body detection and analysis technology, and in particular to an online detection system and method for bisphenol A in water. Background Technology

[0002] With rapid industrial development, bisphenol A (BPA), as an important industrial raw material, is widely used in plastic products, food packaging, medical devices, and other fields. However, BPA can easily enter the aquatic environment through wastewater discharge during production and use, posing a potential threat to ecosystems and human health. BPA has endocrine disrupting properties; even low-concentration exposure can trigger a series of biological effects, such as reproductive toxicity, neurotoxicity, and carcinogenicity. Therefore, real-time and accurate online detection of BPA concentration in water bodies has become one of the key tasks in the field of environmental monitoring and pollution control.

[0003] The chemical properties of bisphenol A are significantly affected by the pH of the water: under extreme pH conditions, bisphenol A may undergo hydrolysis, adsorption, or form transformation, leading to changes in its ion content, which in turn seriously affects the stability and accuracy of the detection signal. For example, when a smart sensor with a built-in pH sensor module detects that the pH of the water is close to 10, bisphenol A may exist in ionic form, and its electrochemical response or fluorescence signal may be significantly weakened, causing the detection value to deviate from the true concentration. Under neutral or weakly acidic / alkaline conditions, the molecular form of bisphenol A is more stable, and the detection signal is more reliable.

[0004] The pH value of the same water body fluctuates at different discharge times, and the pH values ​​of different discharging water bodies differ significantly. Existing online detection systems mostly employ a fixed-time sampling strategy, failing to fully consider the impact of dynamic pH fluctuations on detection accuracy. In unfavorable pH ranges, frequent detection may lead to invalid data or increased errors due to changes in the state of bisphenol A (BPA), wasting detection resources and potentially masking the true pollution trend. Conversely, in favorable pH ranges, insufficient detection frequency may miss crucial concentration changes, reducing monitoring timeliness. Therefore, how to dynamically adjust the detection strategy based on real-time pH changes is a core issue for improving the accuracy and efficiency of online BPA detection. To this end, this invention provides an online detection system and method for BPA in water bodies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an online detection system for bisphenol A in water, as well as a detection method based on this system, to effectively improve the accuracy and efficiency of online bisphenol A detection.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: On one hand, the present invention provides an online detection method for bisphenol A in water, comprising: The pH value of the current water body is detected online to determine the status of bisphenol A in the current water body; If the current state of bisphenol A in the water body is a bisphenol A coexistence state, then extract multiple sets of historical water body online detection data within the historical pH online detection period, and analyze the degree of coupling correlation between the water body pH detection value and the proportion of bisphenol A ions based on the multiple sets of historical water body online detection data; By comparing the trend of pH value changes in water bodies over multiple historical online pH monitoring periods with the trend of pH value changes in water bodies over the online pH monitoring period, a reference line for pH prediction of water bodies is selected. Based on the pH prediction reference line for water bodies, a pH prediction analysis line for water bodies is determined. The trend of pH value changes in water bodies during the online pH detection period is predicted and analyzed to determine the optimal time period for online detection.

[0007] In a further aspect of the present invention, the process for determining the state of bisphenol A in the current water body is as follows: Set a pH online detection cycle and divide the pH online detection cycle into several pH online detection points. Extract the wastewater inlet, wastewater midpoint and wastewater outlet of the industrial wastewater discharge section as inlet space detection point, midpoint space detection point and outlet space detection point respectively. The pH values ​​and corresponding water volumes at the inlet, midpoint, and outlet spatial detection points were obtained at the online pH monitoring points. The pH values ​​at each spatial detection point at the corresponding online pH monitoring point were then analyzed using the H2O method. + After concentration conversion, spatial H is obtained. + concentration; The spatial H corresponding to each spatial detection point at the online pH detection point. + After calculating the product of concentration and corresponding water volume, sum them up, and then perform H2 calculation. + Concentration inversion calculation yields the pH value of the water body; If the pH value of the water body is within the preset pH range, it will be displayed as a bisphenol A coexistence signal.

[0008] In a further embodiment of the present invention, the analysis process for determining the coupling degree between the pH detection value of water and the proportion of bisphenol A ions is as follows: All pH test values ​​of water bodies were substituted into a two-dimensional coordinate system according to the time sequence corresponding to the historical pH online monitoring period to construct a historical pH change curve of water bodies. Substitute all the bisphenol A ion percentages into a two-dimensional coordinate system according to the time sequence corresponding to the historical pH online detection period to construct a historical bisphenol A ion change curve; Extract the peak and trough coordinates from the historical pH change curve of the water body, and use the curve between adjacent peak and trough coordinates as pH peak and trough analysis lines to obtain multiple pH peak and trough analysis lines. The peak and trough coordinates of historical bisphenol A ion change curves were extracted, and the curves between adjacent peak and trough coordinates were used as bisphenol A ion peak-trough analysis lines to obtain multiple bisphenol A ion peak-trough analysis lines. Multiple pH peak and valley analysis lines were sorted according to their time sequence and denoted as A1, A2, A3, A4, ... An; The multiple bisphenol A ion peak and valley analysis lines were sorted according to their time sequence and denoted as B1, B2, B3, B4, ..., Bm, respectively. The number of pH peak-valley analysis lines n is equal to the number of bisphenol A ion peak-valley analysis lines m, and An represents the nth pH peak-valley analysis line, while Bm represents the mth bisphenol A ion peak-valley analysis line.

[0009] In a further embodiment of the present invention, the process for determining the coupling degree between the pH detection value of the water body and the proportion of bisphenol A ions is as follows: Extract the historical online detection points corresponding to the endpoint coordinates of the A1pH peak and valley analysis line: the start time point and the end time point of A1pH, and the historical online detection points corresponding to the endpoint coordinates of the B1bisphenol A ion peak and valley analysis line: the start time point and the end time point of B1 ion. The interval between the start time of A1pH and the start time of B1 ion, and the interval between the end time of A1pH and the end time of B1 ion, are obtained as the proportion of the historical pH online detection cycle, and are used as the unit start interval ratio and the unit end interval ratio. The units are summed to obtain the unit time interval value, and the sum is averaged to obtain the associated time interval value. The distance between the two endpoints of the A1 pH peak and valley analysis line and the distance between the two endpoints of the B1 bisphenol A ion peak and valley analysis line are obtained respectively. These are used as the unit pH change value and the unit ion proportion change value. After calculating the ratio to obtain the unit change analysis value, the standard deviation is calculated to obtain the correlation degree change value. The coupling correlation analysis value is obtained by summing the correlation time interval value and the correlation degree change value; If the change in correlation degree is less than or equal to the correlation degree change threshold, it is displayed as a tightly coupled signal.

[0010] In a further aspect of this invention, the process of comparing the trend of pH changes in water bodies across multiple historical online pH monitoring periods with the trend of pH changes in water bodies within the online pH monitoring period is as follows: During the pH online detection period, the pH values ​​of the water body are substituted into a two-dimensional coordinate system according to the time sequence obtained, and the current pH change curve of the water body is constructed. The endpoint coordinates of the current pH change curve are used as the endpoint coordinates of the historical pH change curve, and the local historical pH change curve is used as the reference line for the pH of the water body. The local curve between two adjacent coordinates on the pH reference line of the water body is used as the pH reference sub-line; The local curve between two adjacent coordinates on the current pH change curve of the water body is taken as the current pH sub-line; The slopes of the first pH reference sub-line and the slope of the first current pH sub-line are obtained respectively, and the difference is calculated. The absolute value is then taken to obtain the sub-line trend comparison value. The trend similarity comparison value is obtained by summing and averaging all the sub-line trend comparison values.

[0011] In a further aspect of this invention, the process of comparing the trend of pH changes in water bodies over multiple historical online pH monitoring periods with the trend of pH changes in water bodies over the online pH monitoring periods, from the perspective of degree of change, is as follows: By placing the pH reference line of the water body and the current pH change curve of the water body in a two-dimensional coordinate system, a similarity comparison coordinate model is constructed. Within the similarity comparison coordinate model, the first coordinate point on the pH reference line of the water body and the first coordinate point on the current pH change curve of the water body are extracted. After calculation and processing using the coordinate distance calculation formula, the ratio with the length of the current pH change curve of the water body is calculated to obtain the single-point degree comparison value. The mean of all individual degree comparison values ​​is summed to obtain the degree similarity comparison value.

[0012] In a further embodiment of the present invention, the process for determining the pH prediction reference line for water bodies is as follows: The similarity comparison values ​​are summed with the degree similarity comparison values ​​to obtain the similarity comparison analysis values; The similarity comparison analysis values ​​corresponding to all historical pH online detection cycles are compared, and the historical water body pH change curve corresponding to the water body pH reference line with the smallest similarity comparison analysis value is selected as the water body pH prediction reference line.

[0013] In a further embodiment of the present invention, the process for determining the pH prediction analysis line of the water body is as follows: The pH prediction analysis line is determined by taking the endpoint coordinates on the current water body pH change curve as the starting intercept coordinates of the water body pH prediction reference line, and taking the original termination coordinates of the water body pH prediction reference line as the termination intercept coordinates of the water body pH prediction reference line.

[0014] In a further aspect of the present invention, the process for determining the optimal time period for online detection is as follows: Mark the minimum value of the preset water body pH range on the water body pH prediction analysis line, and draw an optimal pH detection line parallel to the X-axis. Extract the Y-axis coordinates of the water body pH prediction analysis line that are below the optimal pH detection line. Combine the X-axis coordinates of the water body pH prediction analysis line that are below the optimal pH detection line and are continuous in time to determine the optimal time period for online detection.

[0015] On the other hand, the present invention provides an online detection system for bisphenol A in water, comprising: Status assessment module: Detects the pH value of the current water body online to determine the status of bisphenol A in the current water body; Coupling Analysis Module: If the current state of bisphenol A in the water body is a bisphenol A coexistence state, then extract multiple sets of historical water body online detection data within the historical pH online detection period, and analyze the degree of coupling correlation between the water body pH detection value and the proportion of bisphenol A ions based on the multiple sets of historical water body online detection data; Reference filtering module: Compare the trend of pH value changes in water bodies over multiple historical online pH monitoring periods with the trend of pH value changes in water bodies over the online pH monitoring period to filter out the pH prediction reference line for water bodies. Reference Prediction Module: Based on the pH prediction reference line of the water body, determine the pH prediction analysis line of the water body, predict and analyze the trend of pH value changes in the water body during the online pH detection period, and determine the optimal time period for online detection.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention can perform online detection of the pH value of the current water body to determine the state of bisphenol A (BPA) in the water. If BPA is in a coexisting state, the coupling correlation between the pH value and the proportion of BPA ions can be analyzed to effectively distinguish whether the problem is with the detection accuracy of the online detection equipment or with the influence of the pH of the water body itself on the BPA concentration detection. If the problem is with the detection accuracy of the online detection equipment, the parameter settings of the online detection equipment can be optimized to improve the detection accuracy of BPA concentration in the water. It can also serve as benchmark data for predicting the state and concentration change trend of BPA. When BPA is in a low ionic state, it can improve the online detection frequency of BPA concentration in the water while improving the accuracy of BPA concentration detection.

[0017] 2. This invention can compare the trend of water pH values ​​over multiple historical online pH monitoring periods with the trend of water pH values ​​within the online pH monitoring period to screen out a water pH prediction reference line and predict this trend. When the pH value is about to enter an unfavorable range for detection, it avoids the adverse effects of significant changes in the state of bisphenol A on detection accuracy. Based on the water pH prediction reference line, a water pH prediction analysis line is determined to predict and analyze the trend of water pH values ​​within the online pH monitoring period, determine the optimal time for online detection, and ensure effective detection of bisphenol A at different time periods, providing continuous and reliable data support for wastewater treatment and discharge in factories. When the pH value is in a favorable range for detection, the number of tests can be appropriately increased, while when the pH value is in an unfavorable range, online detection can be avoided to reduce detection errors caused by changes in the state of bisphenol A. Attached Figure Description

[0018] Figure 1 This is a flowchart of the steps of the online detection method for bisphenol A in water according to the present invention; Figure 2 This is a flowchart illustrating the online detection method for bisphenol A in water according to the present invention. Figure 3 This is a functional block diagram of the online detection system for bisphenol A in water bodies according to the present invention. Detailed Implementation

[0019] The technical solution of the present invention will be further described in a non-limiting manner below with reference to the accompanying drawings and specific embodiments.

[0020] Example 1 In the stable discharge of industrial wastewater from factories, online detection of bisphenol A (BPA) in the wastewater is necessary. During this process, the pH level of the water significantly affects BPA concentration. When the pH is below 7, BPA exists in a molecular state, which is beneficial for accurate online detection. However, when the pH is above 10, BPA exists in an ionic state. In this ionic state, BPA is more prone to decomposition or adhesion to solid surfaces in the water, hindering online detection and potentially interfering with the process. The actual concentration of bisphenol A (BPA); when the pH of the water body is between 7 and 10, BPA exists in both molecular and ionic states. Since the state of BPA in the water body changes with the pH, for example, when the pH is 9.6, BPA exists in both molecular and ionic states. When the pH changes from 9.6 to 9.8, the proportion of ionic BPA is greater than that of molecular BPA. Therefore, when online monitoring of BPA concentration in the water body, the detected concentration deviates significantly from the actual concentration of BPA in the water body. Figures 1-2 As shown, this embodiment of the invention provides an online detection method for bisphenol A in water, specifically including the following steps: Step 1: Detect the pH value of the current water body online to determine the status of bisphenol A in the current water body; It should be noted that the current state of bisphenol A in the water body can be bisphenol A molecular signal, bisphenol A ionic signal, and bisphenol A coexistence signal. Among them, the bisphenol A coexistence state refers to the state of bisphenol A in the water body where molecules and ions coexist. In some embodiments, a pH online detection cycle is set, and the pH online detection cycle is divided into several pH online detection points, wherein the time interval between adjacent pH online detection points is equal; For example, the wastewater discharge inlet, wastewater discharge midpoint, and wastewater discharge outlet of the industrial wastewater discharge section are extracted as the inlet space detection point, midpoint space detection point, and outlet space detection point, respectively. The pH value and corresponding water volume of the inlet spatial monitoring point at the online pH detection point were obtained respectively. The pH value of the inlet spatial monitoring point at the online pH detection point was then analyzed by H. + After concentration conversion, the inlet space H is obtained. + Concentration, will the inlet space H + The concentration is multiplied by the corresponding water volume to obtain the inlet space detection value; The pH value and corresponding water volume at the midpoint spatial detection point and the online pH detection point were obtained respectively. The pH value at the midpoint spatial detection point and the online pH detection point were then analyzed using H... +After concentration conversion, the midpoint space H is obtained. + Concentration, the midpoint space H + The concentration is multiplied by the corresponding water volume to obtain the midpoint spatial detection value; The pH value and corresponding water volume at the outlet space monitoring point at the online pH monitoring point were obtained respectively. The pH value at the outlet space monitoring point at the online pH monitoring point was then analyzed using H... + After concentration conversion, the outlet space H is obtained. + Concentration, will the outlet space H + The concentration is multiplied by the corresponding water volume to obtain the outlet space detection value; The import space detection value, midpoint space detection value, and export space detection value are summed, and then H is calculated. + Concentration inversion calculation yields the pH value of the water body; If the pH value of the water body is less than the minimum extreme value within the preset pH range, it indicates that the water body is acidic (pH less than 7), and the state of bisphenol A in the water body is molecular, which is displayed as a bisphenol A molecular signal. If the pH value of the water body is greater than the maximum value within the preset pH range, it indicates that the water body is strongly alkaline (pH greater than 10), and the state of bisphenol A in the water body is ionic, which is displayed as a bisphenol A ion signal. If the pH value of the water body is within the preset pH range, it indicates that the water body is weakly alkaline (pH greater than 7 and less than 10), and the state of bisphenol A in the water body is that of molecules and ions coexist, which is displayed as a bisphenol A coexistence signal. It should be noted that the purpose of determining the current state of bisphenol A in the water is as follows: In terms of detection accuracy, timely determination of the current state of bisphenol A in the water during online detection allows for a quick assessment of whether the current detection conditions are suitable. If bisphenol A is found to be in a state unfavorable for detection (such as an ionic state under strong alkalinity and with a large amount of particulate matter), timely measures can be taken to adjust the situation, thus avoiding the impact of bisphenol A being in an ionic state in the water on the accuracy of online detection of bisphenol A concentration.

[0021] Step 2: If the current state of bisphenol A in the water body is a coexistence state, then extract multiple sets of historical water body online detection data within the historical pH online detection period, and analyze the degree of coupling correlation between the water body pH detection value and the proportion of bisphenol A ions based on the multiple sets of historical water body online detection data. It should be noted that the historical water body online monitoring data includes historical water body pH values ​​(greater than 7 and less than 10) and the proportion of bisphenol A ions. The historical water body pH values ​​are within the preset water body pH range, and the proportion of bisphenol A ions refers to the ratio of ionic bisphenol A to molecular bisphenol A. Furthermore, the multiple sets of historical water body online monitoring data are time-continuous data. For example, within the historical pH online monitoring period, the water body pH value and bisphenol A ion ratio at each historical online monitoring point are obtained. The historical online monitoring points within the historical pH online monitoring period are divided in the same way as the online monitoring points within the pH online monitoring period. In some embodiments, all pH values ​​of water bodies are substituted into a two-dimensional coordinate system according to the time sequence corresponding to the historical pH online detection cycle to construct a historical pH change curve of water bodies. In the historical water body pH change curve, the X-axis represents time, and the Y-axis represents the measured pH value of the water body; Substitute all the bisphenol A ion percentages into a two-dimensional coordinate system according to the time sequence corresponding to the historical pH online detection period to construct a historical bisphenol A ion change curve; In the historical bisphenol A ion change curve, the X-axis represents time and the Y-axis represents the proportion of bisphenol A ions. Extract the peak and trough coordinates from the historical pH change curve of the water body, and use the curve between adjacent peak and trough coordinates as pH peak and trough analysis lines to obtain multiple pH peak and trough analysis lines. The peak and trough coordinates of historical bisphenol A ion change curves were extracted, and the curves between adjacent peak and trough coordinates were used as bisphenol A ion peak-trough analysis lines to obtain multiple bisphenol A ion peak-trough analysis lines. Multiple pH peak and valley analysis lines were sorted according to their time sequence and denoted as A1, A2, A3, A4, ... An; The multiple bisphenol A ion peak and valley analysis lines were sorted according to their time sequence and denoted as B1, B2, B3, B4, ..., Bm, respectively. It should be noted that the number of pH peak and valley analysis lines n is equal to the number of bisphenol A ion peak and valley analysis lines m, and An represents the nth pH peak and valley analysis line, and Bm represents the mth bisphenol A ion peak and valley analysis line. For example, the historical online detection points corresponding to the coordinates of the two endpoints of the A1pH peak-valley analysis line are extracted as the start time point and end time point of A1pH. The historical online detection points corresponding to the two endpoints of the B1 bisphenol A ion peak-valley analysis line were extracted as the B1 ion start time point and B1 ion end time point. The interval between the A1 pH start time point and the B1 ion start time point is obtained as the proportion of the historical pH online detection cycle duration, and is used as the unit start time interval ratio. The interval between the A1 pH termination time point and the B1 ion termination time point is obtained as the proportion of the historical pH online detection cycle duration, and is used as the unit termination interval ratio. The sum of the unit start interval ratio and the unit end interval ratio is used to obtain the unit aging interval value; The summation of all unit time interval values ​​is used to calculate the average value, thus obtaining the associated time interval value. For example, the distance between the coordinates of the two endpoints of the A1pH peak-valley analysis line is obtained as the unit pH change value; The distance between the two endpoints of the B1 bisphenol A ion peak-valley analysis line was obtained as the change value of the unit ion proportion. The ratio of the unit pH change value to the unit ion percentage change value is calculated to obtain the unit change analysis value; The standard deviation of all unit change analysis values ​​is calculated to obtain the change value of correlation degree; The coupling correlation analysis value is obtained by summing the correlation time interval value and the correlation degree change value; Understandably, the coupling correlation analysis value represents the degree of correlation between water pH and the proportion of bisphenol A ions in terms of both temporal synchronicity and similarity of change. On the one hand, the correlation time interval reflects the degree of synchronicity between water pH and the proportion of bisphenol A ions in the time dimension. On the other hand, the change in the correlation degree reflects the similarity of the changing trends between the change range of water pH and the change range of bisphenol A ions. If the coupling correlation analysis value is smaller, it indicates a stronger coupling correlation between water pH and the proportion of bisphenol A ions, that is, a stronger correlation in both time and magnitude of change. If the coupling correlation analysis value is larger, it indicates a weaker coupling correlation between water pH and the proportion of bisphenol A ions, that is, a weaker correlation in both time and magnitude of change. If the change in correlation degree is greater than the threshold for correlation degree change, it indicates that the correlation between the pH detection value of the water body and the proportion of bisphenol A ions is not strong in terms of time and magnitude of change, which shows a weakly coupled signal. If the change in correlation degree is less than or equal to the threshold for change in correlation degree, it indicates that the correlation between the pH detection value of the water body and the proportion of bisphenol A ions is relatively close in terms of time and change magnitude, which shows a tightly coupled correlation signal. The purpose of analyzing the coupling correlation between water pH detection values ​​and the proportion of bisphenol A ions is to reflect the degree of influence of water pH changes on the proportion of bisphenol A ions, so as to optimize the parameter settings of online detection equipment and improve the detection accuracy of online detection equipment for bisphenol A concentration in water. After understanding the correlation between water pH and the proportion of bisphenol A ions, the online detection system can predict the state and concentration trend of bisphenol A based on real-time pH data. When bisphenol A is in a low ionic state, the system can improve the accuracy of online detection of bisphenol A concentration in water while increasing the frequency of detection.

[0022] The specific solution of this invention is as follows: The pH value of the current water body is detected online to determine the state of bisphenol A (BPA) in the water. If the current state of BPA in the water is a coexisting state, multiple sets of historical online detection data are extracted. Based on these data, the coupling correlation between the pH value and the proportion of BPA ions is analyzed to determine whether the problem lies in the accuracy of the online detection equipment or the influence of the water's pH on the BPA concentration detection. If the problem is in the accuracy of the online detection equipment, the parameter settings of the equipment can be optimized to improve its accuracy in detecting BPA concentration. This data can also serve as a benchmark for predicting the state and concentration trends of BPA. When BPA is in a low ionic state, the accuracy of online detection of BPA concentration in the water is improved while simultaneously increasing the frequency of detection.

[0023] Example 2 like Figures 1-2 As shown, the online detection method for bisphenol A in water according to an embodiment of the present invention further includes the following steps: Step 3: Compare the trend of pH value changes in water bodies over multiple historical online pH monitoring periods with the trend of pH value changes in water bodies over the online pH monitoring period, and select the reference line for pH prediction. In some embodiments, during the pH online detection cycle, the pH detection values ​​of the water body are substituted into a two-dimensional coordinate system according to the obtained time sequence to construct the current pH change curve of the water body. In the current pH change curve of the water body, the X-axis represents time, and the Y-axis represents the pH value of the water body. The endpoint coordinates of the current water body pH change curve are used as the endpoint coordinates of the historical water body pH change curve, and the local historical water body pH change curve is used as the reference line for water body pH. The local curve between two adjacent coordinates on the pH reference line of the water body is used as the pH reference sub-line; The local curve between two adjacent coordinates on the current pH change curve of the water body is taken as the current pH sub-line; It should be noted that since the historical online detection point division method within the historical pH online detection cycle is the same as the online detection point division method within the pH online detection cycle, the pH reference sub-line and the current pH sub-line are in one-to-one correspondence in the time dimension. For example, the historical online monitoring point corresponding to the first pH reference sub-line on the pH reference line for water bodies is... , Historical online monitoring points: The historical online monitoring point corresponding to the first current pH sub-line on the current water body pH change curve is... , Historical online detection points; For example, the slope of the first pH reference sub-line and the slope of the first current pH sub-line are obtained respectively, and the difference is calculated and the absolute value is taken to obtain the sub-line trend comparison value. The trend similarity comparison value is obtained by summing and averaging all the sub-line trend comparison values; By placing the pH reference line of the water body and the current pH change curve of the water body in a two-dimensional coordinate system, a similarity comparison coordinate model is constructed. For example, within the similarity comparison coordinate model, the first coordinate point on the pH reference line of the water body and the first coordinate point on the current pH change curve of the water body are extracted. After calculation and processing using the coordinate distance calculation formula, the ratio is calculated with the length of the current pH change curve of the water body to obtain the single-point degree comparison value. It should be noted that since the historical online monitoring point division method within the historical pH online monitoring period is the same as the online monitoring point division method within the pH online monitoring period, the coordinate points on the water body pH reference line and the current water body pH change curve are in a one-to-one correspondence in the time dimension, that is, the horizontal coordinates of the coordinate points are the same. The degree similarity comparison value is obtained by summing and averaging all the single-point degree comparison values. The similarity comparison values ​​are summed with the degree similarity comparison values ​​to obtain the similarity comparison analysis values; The similarity comparison analysis value represents the degree of similarity between the trend of pH value changes in the water body during the historical pH online monitoring period and the trend of pH value changes in the current pH online monitoring period, from two key dimensions: trend similarity and degree similarity. On the one hand, the trend similarity comparison value reflects the overall similarity between the historical and current pH value changes; on the other hand, the degree similarity comparison value reflects the degree of similarity between the historical and current pH values ​​in terms of specific numerical values. Compare the similarity analysis values ​​corresponding to all historical pH online detection cycles, and select the historical water body pH change curve corresponding to the water body pH reference line with the smallest similarity analysis value as the water body pH prediction reference line. It should be noted that the purpose of screening the water body pH prediction reference line is to predict this trend of change by using the water body pH prediction reference line. When the pH value is about to enter the range that is not conducive to detection (such as approaching 10), measures can be taken in advance or the detection strategy can be adjusted to avoid the adverse effects on the detection accuracy caused by the large change of bisphenol A state. Furthermore, based on the predicted pH value change trend, the detection time and resources can be rationally arranged to ensure stable and effective detection of bisphenol A in different time periods, providing continuous and reliable data support for the factory's wastewater treatment and discharge. When the pH value is in a favorable detection range, the number of tests can be appropriately increased to obtain more detailed data; while when the pH value is in an unfavorable range, unnecessary tests can be reduced to save detection time and resources, improve overall detection efficiency, and thus achieve a rational arrangement of online detection time. Step 4: Based on the pH prediction reference line, determine the pH prediction analysis line, predict and analyze the trend of pH value changes during the online pH detection period, and determine the optimal time period for online detection; In some embodiments, the endpoint coordinates on the current water body pH change curve are used as the starting intercept coordinates of the water body pH prediction reference line, and the original termination coordinates of the water body pH prediction reference line are used as the termination intercept coordinates of the water body pH prediction reference line to determine the water body pH prediction analysis line. Mark the minimum value of the preset water body pH range on the water body pH prediction analysis line, and draw an optimal pH detection line parallel to the X-axis. Extract the coordinates of the Y-axis on the water body pH prediction and analysis line that are below the optimal pH detection line. Combine the X-axis coordinates of the water body pH prediction and analysis line that are below the optimal pH detection line and are continuous in time to obtain the optimal time period for online detection. The specific solution in this embodiment is as follows: The trend of pH value changes in water bodies over multiple historical online pH monitoring periods is compared with the trend of pH value changes in water bodies within the online pH monitoring period. A pH prediction reference line is selected to predict this trend. This prevents the adverse effects of significant changes in the state of bisphenol A on detection accuracy when the pH value is about to enter an unfavorable range for detection. Based on the pH prediction reference line, a pH prediction analysis line is determined to predict and analyze the trend of pH value changes in water bodies within the online pH monitoring period, determining the optimal time for online detection. This ensures stable and effective detection of bisphenol A in different time periods, providing continuous and reliable data support for wastewater treatment and discharge in factories. When the pH value is in a favorable detection range, the number of detections can be appropriately increased, while when the pH value is in an unfavorable range, online detection is avoided to reduce detection errors caused by changes in the state of bisphenol A.

[0024] Example 3 like Figure 3 As shown in the figure, this embodiment of the invention also provides an online detection system for bisphenol A in water, specifically including: Status assessment module: Detects the pH value of the current water body online to determine the status of bisphenol A in the current water body; Coupling Analysis Module: If the current state of bisphenol A in the water body is a bisphenol A coexistence state, then extract multiple sets of historical water body online detection data within the historical pH online detection period, and analyze the degree of coupling correlation between the water body pH detection value and the proportion of bisphenol A ions based on the multiple sets of historical water body online detection data; Reference filtering module: Compare the trend of pH value changes in water bodies over multiple historical online pH monitoring periods with the trend of pH value changes in water bodies over the online pH monitoring period to filter out the pH prediction reference line for water bodies. Reference Prediction Module: Based on the pH prediction reference line of the water body, determine the pH prediction analysis line of the water body, predict and analyze the trend of pH value changes in the water body during the online pH detection period, and determine the optimal time period for online detection.

[0025] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. An online detection method for bisphenol A in water, characterized in that, include: The pH value of the current water body is detected online to determine the status of bisphenol A in the current water body; If the current state of bisphenol A in the water body is a bisphenol A coexistence state, then extract multiple sets of historical water body online detection data within the historical pH online detection period, and analyze the degree of coupling correlation between the water body pH detection value and the proportion of bisphenol A ions based on the multiple sets of historical water body online detection data; By comparing the trend of pH value changes in water bodies over multiple historical online pH monitoring periods with the trend of pH value changes in water bodies over the online pH monitoring period, a reference line for pH prediction of water bodies is selected. Based on the pH prediction reference line for water bodies, a pH prediction analysis line for water bodies is determined. The trend of pH value changes in water bodies during the online pH detection period is predicted and analyzed to determine the optimal time period for online detection.

2. The online detection method for bisphenol A in water according to claim 1, characterized in that, The process for determining the current state of bisphenol A in the water body is as follows: Set a pH online detection cycle and divide the pH online detection cycle into several pH online detection points. Extract the wastewater inlet, wastewater midpoint and wastewater outlet of the industrial wastewater discharge section as inlet space detection point, midpoint space detection point and outlet space detection point respectively. The pH values ​​and corresponding water volumes at the inlet, midpoint, and outlet spatial detection points were obtained at the online pH monitoring points. The pH values ​​at each spatial detection point at the corresponding online pH monitoring point were then analyzed using the H2O method. + After concentration conversion, spatial H is obtained. + concentration; Corresponding each spatial detection point to the spatial H at the online pH detection point + After calculating the product of concentration and corresponding water volume, sum them up, and then perform H2 calculation. + Concentration inversion calculation yields the pH value of the water body; If the pH value of the water body is within the preset pH range, it will be displayed as a bisphenol A coexistence signal.

3. The online detection method for bisphenol A in water according to claim 2, characterized in that, The analysis process for the coupling degree between water pH measurement values ​​and the proportion of bisphenol A ions is as follows: All pH test values ​​of water bodies were substituted into a two-dimensional coordinate system according to the time sequence corresponding to the historical pH online monitoring period to construct a historical pH change curve of water bodies. Substitute all the bisphenol A ion percentages into a two-dimensional coordinate system according to the time sequence corresponding to the historical pH online detection period to construct a historical bisphenol A ion change curve; Extract the peak and trough coordinates from the historical pH change curve of the water body, and use the curve between adjacent peak and trough coordinates as pH peak and trough analysis lines to obtain multiple pH peak and trough analysis lines. The peak and trough coordinates of historical bisphenol A ion change curves were extracted, and the curves between adjacent peak and trough coordinates were used as bisphenol A ion peak-trough analysis lines to obtain multiple bisphenol A ion peak-trough analysis lines. Multiple pH peak and valley analysis lines were sorted according to their time sequence and denoted as A1, A2, A3, A4, ... An; The multiple bisphenol A ion peak and valley analysis lines were sorted according to their time sequence and denoted as B1, B2, B3, B4, ..., Bm, respectively. The number of pH peak-valley analysis lines n is equal to the number of bisphenol A ion peak-valley analysis lines m, and An represents the nth pH peak-valley analysis line, while Bm represents the mth bisphenol A ion peak-valley analysis line.

4. The online detection method for bisphenol A in water according to claim 1, characterized in that, The process for determining the coupling degree between water pH measurement values ​​and the proportion of bisphenol A ions is as follows: Extract the historical online detection points corresponding to the endpoint coordinates of the A1pH peak and valley analysis line: the start time point and the end time point of A1pH, and the historical online detection points corresponding to the endpoint coordinates of the B1bisphenol A ion peak and valley analysis line: the start time point and the end time point of B1 ion. The interval between the start time of A1pH and the start time of B1 ion, and the interval between the end time of A1pH and the end time of B1 ion, are obtained as the proportion of the historical pH online detection cycle, and are used as the unit start interval ratio and the unit end interval ratio. The units are summed to obtain the unit time interval value, and the sum is averaged to obtain the associated time interval value. The distance between the two endpoints of the A1 pH peak and valley analysis line and the distance between the two endpoints of the B1 bisphenol A ion peak and valley analysis line are obtained respectively. These are used as the unit pH change value and the unit ion proportion change value. After calculating the ratio to obtain the unit change analysis value, the standard deviation is calculated to obtain the correlation degree change value. The coupling correlation analysis value is obtained by summing the correlation time interval value and the correlation degree change value; If the change in correlation degree is less than or equal to the correlation degree change threshold, it is displayed as a tightly coupled signal.

5. The online detection method for bisphenol A in water according to claim 1, characterized in that: From the perspective of trend changes, the process of comparing the trend of pH value changes in water bodies over multiple historical online pH monitoring periods with the trend of pH value changes in water bodies over the online pH monitoring period is as follows: During the pH online detection period, the pH values ​​of the water body are substituted into a two-dimensional coordinate system according to the time sequence obtained, and the current pH change curve of the water body is constructed. The endpoint coordinates of the current pH change curve are used as the endpoint coordinates of the historical pH change curve, and the local historical pH change curve is used as the reference line for the pH of the water body. The local curve between two adjacent coordinates on the pH reference line of the water body is used as the pH reference sub-line; The local curve between two adjacent coordinates on the current pH change curve of the water body is taken as the current pH sub-line; The slopes of the first pH reference sub-line and the slope of the first current pH sub-line are obtained respectively, and the difference is calculated. The absolute value is then taken to obtain the sub-line trend comparison value. The trend similarity comparison value is obtained by summing and averaging all the sub-line trend comparison values.

6. The online detection method for bisphenol A in water according to claim 5, characterized in that: The process of comparing the trend of pH value changes in water bodies over multiple historical online pH monitoring periods with the trend of pH value changes in water bodies over the same online pH monitoring period, from the perspective of degree of change, is as follows: By placing the pH reference line of the water body and the current pH change curve of the water body in a two-dimensional coordinate system, a similarity comparison coordinate model is constructed. Within the similarity comparison coordinate model, the first coordinate point on the pH reference line of the water body and the first coordinate point on the current pH change curve of the water body are extracted. After calculation and processing using the coordinate distance calculation formula, the ratio with the length of the current pH change curve of the water body is calculated to obtain the single-point degree comparison value. The mean of all individual degree comparison values ​​is summed to obtain the degree similarity comparison value.

7. The online detection method for bisphenol A in water according to claim 6, characterized in that, The process for determining the pH prediction reference line for water bodies is as follows: The similarity comparison values ​​are summed with the degree similarity comparison values ​​to obtain the similarity comparison analysis values; The similarity comparison analysis values ​​corresponding to all historical pH online detection cycles are compared, and the historical water body pH change curve corresponding to the water body pH reference line with the smallest similarity comparison analysis value is selected as the water body pH prediction reference line.

8. The online detection method for bisphenol A in water according to claim 1, characterized in that, The process for determining the pH prediction analysis line for water bodies is as follows: The pH prediction analysis line is determined by taking the endpoint coordinates on the current water body pH change curve as the starting intercept coordinates of the water body pH prediction reference line, and taking the original termination coordinates of the water body pH prediction reference line as the termination intercept coordinates of the water body pH prediction reference line.

9. The online detection method for bisphenol A in water according to claim 8, characterized in that, The process for determining the optimal time for online detection is as follows: Mark the minimum value of the preset water body pH range on the water body pH prediction analysis line, and draw an optimal pH detection line parallel to the X-axis. Extract the Y-axis coordinates of the water body pH prediction analysis line that are below the optimal pH detection line. Combine the X-axis coordinates of the water body pH prediction analysis line that are below the optimal pH detection line and are continuous in time to determine the optimal time period for online detection.

10. An online detection system for bisphenol A in water, characterized in that, include: Status assessment module: Detects the pH value of the current water body online to determine the status of bisphenol A in the current water body; Coupling Analysis Module: If the current state of bisphenol A in the water body is a bisphenol A coexistence state, then extract multiple sets of historical water body online detection data within the historical pH online detection period, and analyze the degree of coupling correlation between the water body pH detection value and the proportion of bisphenol A ions based on the multiple sets of historical water body online detection data; Reference filtering module: Compare the trend of pH value changes in water bodies over multiple historical online pH monitoring periods with the trend of pH value changes in water bodies over the online pH monitoring period to filter out the pH prediction reference line for water bodies. Reference Prediction Module: Based on the pH prediction reference line of the water body, determine the pH prediction analysis line of the water body, predict and analyze the trend of pH value changes in the water body during the online pH detection period, and determine the optimal time period for online detection.

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