Method for rapidly and efficiently determining high-concentration nitrate ions in aqueous solution

Abstract

The invention relates to a method for rapidly and efficiently determining high-concentration nitrate ions in an aqueous solution. The method specifically comprises the following steps: constructing a high-concentration NO3 <-> determination device; carrying out spectrum scanning on NO3 <-> and possible interferents, and determining an optimal measurement wavelength; the optical fiber probe is adjusted, the optical path is changed, and other parameters are not changed; taking ultrapure water as a reference, drawing standard curves under different optical paths, and determining an optimal measurement optical path; under the relatively optimal optical path, adjusting the concentration of the reference solution, drawing a standard curve under different reference solution concentrations, and determining the optimal reference concentration; under the relatively optimal optical path and the optimal reference solution concentration, adjusting a light decay device, changing the initial light intensity in the reference, drawing standard curves under different light intensities, and determining the better light intensity; and fitting the drawn standard curve, and verifying the fitted standard curve. The method is simple to operate, wide in measurement range and high in precision, and has wide application prospects in the fields of spent fuel post-treatment wastewater monitoring, military explosive wastewater monitoring and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical engineering, and mainly relates to a method for quickly and efficiently determining high-concentration nitrate ions in an aqueous solution. Background Art

[0002] In nuclear fuel reprocessing, the evaporation process is usually used to concentrate the backwash aqueous solution containing reusable uranium, plutonium or thorium, as well as radioactive waste. During the long-term operation of the evaporator, a certain amount of organic phases such as tributyl phosphate, radiolysis products and diluents will accumulate due to phase entrainment. In the presence of nitric acid and at high temperatures, it will combine with heavy metal nitrates to form a viscous liquid with a relatively high density. If not exported in time, a thermal runaway reaction will occur at high temperatures, that is, the so-called "red oil" explosion. There have been many "red oil" explosion accidents in reprocessing plants around the world, all of which have caused varying degrees of damage to equipment, buildings and environmental pollution. The common feature of several accidents is that a large amount of tributyl phosphate exists or is accidentally introduced, and at the same time, there are nitric acid and heavy metal nitrates. Some studies believe that the reaction activity of tributyl phosphate and nitric acid is relatively low, and a thermal decomposition reaction can only be triggered under high-concentration nitric acid and high-temperature conditions. However, after the "red oil" explosion accident in 1993, there was a further understanding of the thermal reaction of "red oil". The research by DuPont Company in the United States showed that in the absence of metal ions and diluents, tributyl phosphate and nitric acid can also explode when heated to certain conditions. This shows that the reaction between tributyl phosphate (organic matter) and nitric acid (NO3 - ) is the main factor for the thermal runaway reaction of "red oil", while metal ions and diluents are contributing factors. Therefore, it is necessary to carry out research on the monitoring of NO3 - in the spent fuel reprocessing waste liquid.

[0003] Explosives are a common type of explosive substance, which are widely used in military, industrial and civilian fields. Nitric acid and nitrates, as indispensable components in the production of explosives, are both oxidants and detonation velocity regulators, combustion stabilizers and volume expanders. It has an important impact on the combustion, explosion characteristics and safety of explosives, and is one of the key factors to achieve the expected effects of explosives. When leaks, accidents or illegal acts occur during the production, storage or transportation of explosives, nitrate may enter the wastewater, which is potentially dangerous. Therefore, it is crucial to effectively monitor and treat NO3 - in the explosive wastewater. Through efficient and accurate monitoring, we can understand the content of NO3 - in the wastewater, and accordingly formulate corresponding wastewater treatment plans. Only in this way can we effectively prevent environmental pollution, protect the natural environment and the lives and property of personnel, meet the compliance requirements of laws and regulations, and also contribute to the sustainable development of enterprises and society.

[0004] At present, a variety of methods for detecting and analyzing NO3 - concentration have been developed, including spectrophotometry, electrochemistry analysis, flow injection method, ion chromatography, fluorescence method, electrophoresis method, etc. However, the above methods usually have cumbersome sample pretreatment and can only be used for the determination of trace or micro nitrate in the laboratory, making it difficult to achieve the efficient and rapid determination of high-concentration NO3 - . There is an urgent need to develop a new method for accurately and efficiently determining NO3 - concentration.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The object of the present invention is to provide a method for rapidly and efficiently determining high-concentration nitrate ion in aqueous solution to fill the research gap in this aspect, and to provide a new means and idea for the on-line rapid monitoring of NO3 - in the spent fuel reprocessing waste liquid and other industrial production monitoring fields such as the monitoring of nitro explosive wastewater.

[0007] To achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0008] A method for rapidly and efficiently determining high-concentration nitrate ion in aqueous solution, the method comprising the following steps:

[0009] (1) Assembly of the NO3 - determination instrument: Assemble a high-concentration nitrate determination device using a 5W laser light source, a spectroscopic component, a regulated power supply, an optical attenuator, a probe and its supporting optical fiber. The light source provides multi-wavelength emitted light; the spectroscopic component performs wavelength discrimination and analog-to-digital conversion on the emitted light from the light source and the reflected light from the optical fiber probe, and different specific wavelengths of light can be obtained by adjusting the spectroscopic component, with an error within 0.5 nm; the optical attenuator is used to adjust the light intensity of the emitted light and control it within a suitable range; the optical fiber probe is used to place in the solution to be measured so that the incident light and the reflected light pass through the liquid to attenuate the light intensity, and the distance between the optical fiber probe and its terminal mirror can be adjusted, that is, the optical path in the photometric method can be adjusted. This device realizes the separation of analysis and detection, and when performing concentration measurement, only the optical fiber probe needs to be placed into the sample to be measured, without affecting the original layout and having many other extremely practical advantages.

[0010] (2) Determination of the optimal measurement wavelength: Weigh an appropriate amount of dry sodium nitrate and place it in a beaker, add an appropriate amount of deionized water to prepare a sodium nitrate solution with a certain concentration.

[0011] Perform a spectral scan on the sodium nitrate solution in the range of 250 nm - 500 nm.

[0012] Perform spectral scanning on organic substances such as TBP in the spent fuel reprocessing waste liquid in the range of 250 nm - 500 nm, so as to reduce the influence of organic substances on the determination of nitrate. Select the wavelength with appropriate absorbance and no interference from organic substances such as TBP as the optimal determination wavelength for nitrate.

[0013] (3) Determination of the optimal optical path: Prepare sodium nitrate solutions with different mass fractions, and the concentration range of NO3 - is 0.0% - 20.0%, namely 0.0%, 2.0%, 5.0%, 8.0%, 10.0%, 12.0%, 15.0%, 18.0%, 20.0% respectively. Keep the rest of the parameters unchanged, adjust its probe, and change the optical path to 1.0 mm, 2.0 mm, 5.0 mm, 10.0 mm respectively. Using ultrapure water as the reference, measure its absorbance and draw the standard curves under different optical paths. By comparing the standard curves made with different optical paths, select the optical path with the best correlation coefficient of the standard curve and a larger measurement range as the optimal measurement optical path.

[0014] (4) Determination of the optimal reference concentration: Under the relatively optimal optical path, with the rest of the parameters unchanged, adjust the concentration of its reference solution, which are 0.0% (i.e., ultrapure water), 5.0%, 10.0%, 15.0% mass fraction sodium nitrate solutions as the reference solutions respectively. Configure the sodium nitrate solution gradient with as small a concentration gradient as possible, measure its absorbance and draw the standard curves under different reference solution concentrations. Using different concentrations of NO3 - solution as the reference solution, select the standard curve with absorbance being more sensitive but not overly sensitive to the high-concentration range of NO3 - to achieve a larger measurement range without significantly sacrificing the measurement accuracy. Thus, select its optimal reference concentration.

[0015] (5) Determination of the relatively optimal light intensity: Under the relatively optimal optical path, with the rest of the parameters unchanged, adjust its reference solution to be the same as in (4), adjust the optical attenuator, and change the initial light intensity in the reference. Divide it into two large groups, and the reference solutions in both groups are the same. The light intensity emitted by the light source in group one is the same for each reference concentration, and the initial received light intensity of each reference concentration in group two is the same. (That is, the light intensity of the light source in group one is configured to have a received light intensity of around 60000 counts in ultrapure water and then remains unchanged. For subsequent reference solutions, the optical attenuator is not readjusted, and each reference uses this configuration; in group two, the optical attenuator needs to be adjusted in each reference solution to ensure that the received light intensity in each reference solution is around 60000 counts). Draw the standard curves under different light intensities with the obtained data, and select the one that is more sensitive to high-concentration NO3 - and has the largest measurement range as the standard curve for determination, and repeat to verify its accuracy and precision.

[0016] Using the obtained standard curve, after analyzing it to obtain the modeling formula, with each parameter unchanged, measure each configured simulated post-treatment waste liquid, and obtain the NO3 - concentration in it, compare it with the standard value, and obtain the accuracy and error amount of the standard curve.

[0017] The present invention has significant advantages compared with the prior art:

[0018] 1. Use a self-assembled NO3 - determinator, use 303 nm as the NO3 - determination wavelength, prepare NO3 - solutions with concentration gradients, measure their absorbance by changing the optical path (1.0 mm to 10.0 mm), light intensity (high and low light intensities), and different reference concentrations (0.0% to 15.0%), and plot the standard curve, and select the optical path, reference concentration, and relatively optimal light intensity with the best combination of interference and measurement range.

[0019] 2. Fit the NO3 - standard curve, with a good fitting degree, and prepare simulated post-treatment waste liquid to independently verify the fitted curve, and find that the maximum relative error does not exceed 1.3%. Its measurement meets the requirements. This method is simple to operate, has a wide measurement range, and high precision, and has a wide application prospect in the fields of spent fuel reprocessing wastewater monitoring, military explosive wastewater monitoring, and general industrial production monitoring, etc. Brief Description of the Drawings

[0020] In order to more clearly illustrate the specific implementation manners of the present invention, the drawings required for use in the following description of the specific implementation manners or background technology will be briefly introduced. Obviously, the drawings in the following description are some implementation manners of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a diagram of a self-assembled nitrate ion determination device in the laboratory.

[0022] Figure 2 It is a simplified internal structure diagram of the nitrate ion determination device.

[0023] Figure 3 It is an ultraviolet-visible spectral scan diagram of a sodium nitrate solution.

[0024] Figure 4 It is an ultraviolet-visible spectral scan diagram of a possible interfering substance TBP.

[0025] Figure 5 It is an ultraviolet-visible spectral scan diagram of a possible interfering substance DBP.

[0026] Figure 6 Standard curve graphs plotted at different optical paths.

[0027] Figure 7 Schematic diagram of the influence of reference concentration on measurement.

[0028] Figure 8 Standard curve graphs obtained at different reference concentrations under an optical path of 2.0 mm.

[0029] Figure 9 Standard curve graphs plotted at different light intensities. (a) shows the comparison of high and low light intensities with a 5.0% reference, and (b) shows the comparison of high and low light intensities with a 10% reference.

[0030] Figure 10 Graphs showing the fitting of each segment of the standard curve. (a) shows the fitting of the curve segment from 5.1% to 19.6%, (b) shows the fitting of the curve segment from 20.5% to 27.9%, and (c) shows the fitting of the curve segment from 28.6% to 43.0%. Detailed implementation mode

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and the detailed implementation mode. However, those skilled in the art will understand that the following described embodiments are part of the embodiments of the present invention, rather than all of the embodiments, and are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, other embodiments obtained by those of ordinary skill in the art without creative efforts all belong to the scope protected by the present invention. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the equipment or devices not specified by the manufacturer, they are all conventional products that can be purchased commercially.

[0032] A method for quickly and efficiently determining high-concentration nitrate ions in an aqueous solution, comprising the following steps:

[0033] First, assemble a nitrate determination device using a 5W laser light source, a spectroscopic component, a regulated power supply, an optical attenuator, a probe, and its supporting optical fiber.

[0034] The assembled NO3 - The physical diagram of the determination device is as shown in Figure 1 shown, and the internal structure schematic diagram is as shown in Figure 2 shown.

[0035] Use an ultraviolet-visible spectrophotometer to scan the absorption spectrum of nitric acid to determine its absorption peak. To increase the measurement range and reduce the influence of other substances, select a wavelength with a shorter wavelength and a lower absorption peak as the nitrate ion determination wavelength.

[0036] The ultraviolet-visible spectral scans of sodium nitrate solution, TBP, and DBP are as shown in Figures 3 to 5As shown. It can be seen from the figure that NO3 - has the maximum absorbance near 303 nm. TBP and DBP have no peak absorption near 303 nm and the absorbance is low, that is, organic substances such as TBP and DBP will not interfere with the determination of NO3 - at 303 nm. Therefore, 303 nm can be used as the wavelength for the determination of NO3 - concentration.

[0037] Set the parameters of the NO3 - determinator, keep the other parameters unchanged, adjust its probe, change the optical path to 1.0 mm, 2.0 mm, 5.0 mm, 10.0 mm respectively. At each optical path, configure multiple groups of sodium nitrate solutions with different concentrations. Using ultrapure water as the reference, measure its absorbance at 303 nm and draw the standard curves under different optical paths. Select the optical path with the best correlation coefficient of the standard curve and a larger measurement range as the optimal optical path for measurement.

[0038] The standard curves drawn under different optical paths are as Figure 6 shown. It can be seen from the figure that when the optical path is 2 mm, the measurable range of NO3 - is larger and the linear relationship is better. Considering comprehensively, an optical path of 2 mm can be used as the optimal optical path for the determination of NO3 - measurement.

[0039] Under the relative optimal optical path, with the other parameters unchanged, adjust the concentration of the reference solution, which are 0.0% (i.e., ultrapure water), 5.0%, 10.0%, 15.0% mass fraction sodium nitrate solutions as the reference solutions respectively. Configure the sodium nitrate solution gradient with the concentration gradient interval as small as possible. Measure its absorbance and draw the standard curves under different reference solution concentrations. Using different concentration NO3 - solutions as the reference solutions, select the standard curve that is more sensitive but not overly sensitive to the high concentration range of NO3 - to achieve a larger measurement range without significantly losing the measurement accuracy. Thus, select its optimal reference concentration.

[0040] The influence of different reference concentrations on the measurement results is as Figure 7 shown. It can be seen that within a certain sample concentration range, as the concentration of the reference solution increases, the light intensity C0 in the reference solution decreases. When the range of the sample light intensity C remains unchanged, decreasing C0 will cause the transmittance range to expand and shift to the right as a whole, moving from part a to part b. The same concentration range can obtain a larger and gentler slope part on the curve, reducing the sensitivity of the absorbance to the concentration and increasing the measurement range. Therefore, in the establishment of the standard curve, using different concentration NO3 - solutions as the reference solutions and using the standard curve zero point can explore that the absorbance is more sensitive to the high concentration range of NO3 -A relatively sensitive but not overly sensitive standard curve to achieve a larger measurement range without significant loss of measurement accuracy.

[0041] At an optical path of 2.0 mm, the standard curve obtained by changing the reference concentration is as Figure 8 shown. As can be seen from the figure, when pure water is used as the reference, the drawn standard curve can measure a larger range of NO3 - and has a better linear relationship. Considering comprehensively, pure water is selected as the reference solution for NO3 - determination.

[0042] At the relatively optimal optical path and the best reference concentration, with other parameters unchanged, the optical attenuator is adjusted to change the initial light intensity in the reference. It is divided into two large groups. The reference solutions in both groups are the same. In group one, the light intensity emitted by the light source is the same for each reference concentration. In group two, the initial received light intensity for each reference concentration is the same. (That is, in group one, after the light intensity emitted by the light source is configured to have a received light intensity of around 60000 counts in ultrapure water and remains unchanged, the optical attenuator is not readjusted for subsequent reference solutions, and each reference uses this configuration; in group two, the optical attenuator needs to be adjusted in each reference solution to ensure that the received light intensity in each reference solution is around 60000 counts).

[0043] The comparison of the standard curves drawn at different light intensities is as Figure 9 shown. As can be seen from the figure, the standard curve drawn at high light intensity can measure a larger range of NO3 than the standard light intensity - and has a better linear relationship. Considering comprehensively, high light intensity is selected as the relatively optimal light intensity for NO3 - determination.

[0044] Select the standard curve with the largest measurement concentration and measurement range, and repeat to verify its accuracy and precision; using the obtained standard curve, after analyzing it, obtain the modeling formula. With all parameters unchanged, measure each simulated post-treatment waste liquid configured, and obtain the NO3 - concentration contained in it, and compare it with the standard value to obtain the accuracy and error amount of the standard curve.

[0045] The fitting situation of each segment of the standard curve is as Figure 10 shown in Table 1.

[0046] Table 1 Fitting situation of each segment of the standard curve

[0047] Concentration range Standard curve <![CDATA[Fitness (R 2 )]]> 5.10％～19.6％ <![CDATA[Y1 = -21.5×x 2 + 12.8×x - 0.586]]> 0.999 20.5％～27.9％ <![CDATA[Y2 = -14.1×x 2 + 10.3×x - 0.414]]> 0.997 28.6％～43.0％ <![CDATA[Y3 = -3.52×x 2 + 3.19×x + 0.735]]> 0.991

[0048] Example

[0049] Since it is difficult to obtain high-level radioactive waste liquid and explosive wastewater, by referring to relevant materials, according to the composition table of post-treatment waste liquid given in Table 2, some nitrates are taken and respectively prepared into NO3 -Simulated post-treatment waste liquids with mass fractions of 8.79%, 14.30%, 16.49%, 25.17%, and 32.24% were used to conduct simulated determinations of high-concentration nitrate ions. Using the device as shown in Figure 1 , the optical path of the device was adjusted to 2.0 mm, the light intensity was adjusted appropriately, and the concentration of NO3 in the simulated post-treatment waste liquid was measured at 303 nm; the measured absorbance was substituted into the standard curve to obtain the concentration of NO3 contained therein, and it was compared with the standard value to obtain the accuracy and error amount of the standard curve. - -

[0050] Table 2 Content of Some Metal Nitrates in High-Level Waste Liquid

[0051]

[0052]

[0053] The comparison between the measured concentration of the simulated post-treatment waste liquid and the actual concentration is shown in Table 3. It can be seen from the table that the maximum relative error of the test-verified concentration in each segmented fitting curve does not exceed 1.3%, its average relative error is small, and the range is small, so it should be usable. However, it was found in actual tests that there is still a poor repeatability of data at higher concentrations, and there is room for improvement. In summary, this standard curve can be used to measure NO3 - solutions with a concentration range of 39.0 g / L to 350.0 g / L, and its measurement is feasible.

[0054] Table 3 Independent Verification Results of Fitting Curves

[0055] Serial number True mass fraction Measured mass fraction Relative error 1 8.79％ 8.78％ -0.11％ 2 14.30％ 14.45％ 1.05％ 3 16.49％ 16.44％ -0.30％ 4 25.17％ 24.98％ -0.75％ 5 32.24％ 32.64％ 1.24％

[0056] The above-described embodiments merely represent one implementation manner of the present invention, and its description is relatively detailed and specific, but it should not be construed as a limitation on the scope of the present invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.​​

Claims

1. A method for rapidly and efficiently determining high-concentration nitrate ions in an aqueous solution, characterized in that, It includes the following steps: Assemble the device for determining high-concentration nitrate; Using an ultraviolet-visible spectrophotometer to perform spectral scanning on NO3 - and the possible interfering substance tributyl phosphate (TBP), and selecting the wavelength that excludes the influence of the interfering substance as the optimal measurement wavelength; Prepare a NO3 solution with a concentration gradient - solution, adjust the optical fiber probe, change the optical path from 1.0 mm to 10.0 mm, keep other parameters unchanged, use ultrapure water as a reference, plot the standard curves at different optical paths, and select the optical path with the best correlation coefficient of the standard curve and a larger measurement range as the optimal measurement optical path; Under the relative optimal optical path, with other parameters unchanged, adjust the concentration of its reference solution from 0.0% to 15.0%, plot the standard curves at different reference solution concentrations, and select the standard curve that is more sensitive in the high concentration range to achieve a larger measurement range without significantly sacrificing the measurement accuracy, so as to select its optimal reference solution concentration; - The standard curve that is more sensitive in the high concentration range can achieve a larger measurement range without significantly sacrificing the measurement accuracy, so as to select its optimal reference solution concentration; Under the relative optimal optical path and the best reference solution concentration, with all other parameters unchanged, adjust the optical attenuator to change the initial light intensity in the reference, that is, high light intensity and low light intensity, draw the standard curves at different light intensities, and select the one that is more sensitive to high concentration NO3 - with the largest measurement range as the standard curve for determination, and repeatedly verify its accuracy and precision.

2. The method for rapidly and efficiently determining high-concentration nitrate ions in an aqueous solution according to claim 1, characterized in that The device for determining high-concentration nitrate includes a 5W laser light source, a spectroscopic component, a regulated power supply, an optical attenuator, a probe and its supporting optical fiber; Among them, the regulated power supply transforms voltage to supply energy for the laser light source; the light source provides outgoing light with multiple wavelengths for it; The spectroscopic component performs wavelength discrimination and analog-to-digital conversion on the outgoing light from the light source and the reflected light from the optical fiber probe to obtain light with different specific wavelengths; The optical attenuator is used to adjust the light intensity of the outgoing light and control it within a suitable range; The optical fiber probe is used to be placed in the solution to be measured to allow the incident light and the reflected light to pass through the liquid to attenuate the light intensity. The distance between the optical fiber probe and its terminal mirror can be adjusted, that is, the optical path in the photometric method can be adjusted.

3. The method for rapidly and efficiently determining high-concentration nitrate ions in an aqueous solution according to claim 1, characterized in that, The spent fuel reprocessing waste liquid contains organic substances such as TBP. When analyzing the feasibility of the method for determining NO3 - , it is necessary to consider the influence of organic substances such as TBP on the determination, so as to determine the suitable measurement wavelength. Weigh the dried sodium nitrate and place it in a beaker, add deionized water to prepare a sodium nitrate solution with a certain concentration. Then, take sufficient amounts of TBP and DBP respectively, and perform spectral scanning with a UV-visible spectrophotometer. Select the wavelength that excludes the influence of interfering substances as the best measurement wavelength.

4. The method for rapidly and efficiently determining high-concentration nitrate ions in an aqueous solution according to claim 1, wherein, Prepare sodium nitrate solutions with different mass fractions, and the concentration range of NO3 - is 0.0% - 20.0%. Keeping the other parameters unchanged, adjust its probe, change the optical path to 1.0 mm, 2.0 mm, 5.0 mm, and 10.0 mm respectively. Using ultrapure water as the reference, measure its absorbance and plot the standard curves under different optical paths. By comparing the standard curves made with different optical paths, select the optical path with the best correlation coefficient of the standard curve and a larger measurement range as the optimal optical path for measurement, and select the optical path that is the best combination of interference and measurement range.

5. The method for rapidly and efficiently determining high-concentration nitrate ions in an aqueous solution according to claim 1, characterized in that, Under the relative optimal optical path, with other parameters remaining unchanged, adjust the concentration of its reference solution, which are 0.0%, i.e., ultrapure water, 5.0%, 10.0%, and 15.0% mass fraction sodium nitrate solutions as reference solutions, configure the sodium nitrate solution gradient with the concentration gradient as small as possible, measure its absorbance and plot the standard curves under different reference solutions, using different concentration NO3 - solutions as reference solutions, select the standard curve that is more sensitive but not overly sensitive to the high concentration range of NO3 - to achieve a larger measurement range without significantly sacrificing the measurement accuracy, so as to select its optimal reference concentration.

6. The method for rapidly and efficiently determining high-concentration nitrate ions in an aqueous solution according to claim 1, wherein Under the relative optimal optical path and the best reference concentration, with other parameters unchanged, adjust the optical attenuator to change the initial light intensity in the reference. It is divided into two large groups. The reference solutions in both groups are the same. In Group 1, the light intensity emitted by the light source has the same reference concentration, and in Group 2, the initial received light intensity of each reference concentration is the same; use the obtained data to plot the standard curves at different light intensities, and select the one that is more sensitive to high concentrations of NO3 - and has the largest measurement range as the standard curve for determination, and repeat to verify its accuracy and precision.

7. The method for rapidly and efficiently determining high-concentration nitrate ions in an aqueous solution according to any one of claims 1 to 6, characterized in that, Using the obtained standard curve, after analyzing it, a modeling formula is derived. With all parameters remaining unchanged, each configured simulated post-treatment waste liquid is measured to obtain the NO3 - concentration. By comparing it with the standard value, the accuracy and error amount of the standard curve are obtained.

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