A method for correcting hydrogen isotope ratios in water samples obtained by adsorption

Abstract

This invention discloses a method for correcting the hydrogen isotope ratio of water samples obtained through adsorption, addressing the problems of high cost of existing high-purity chemical water adsorbents and the tendency for deviations in hydrogen isotope ratio test results caused by physical and industrial chemical water adsorbents. The method involves: obtaining known parameters of a water sample and measuring the hydrogen isotope ratio of the water sample after adsorption; constructing a correction formula and extracting the abscissa parameter formula, then substituting the known parameters into the abscissa parameter formula as the abscissa parameter, plotting the hydrogen isotope ratio of each group of water samples as the ordinate parameter, and performing linear fitting to obtain a fitted straight line. The correction formula is then updated by combining the slope and intercept of the fitted straight line. Finally, the test parameters of the water sample to be tested are obtained, and its hydrogen isotope ratio is measured after adsorption. This value is then substituted into the updated correction formula to obtain the corrected hydrogen isotope ratio of the water sample to be tested. This method is simple to operate, has good correction effect, can significantly reduce material costs, and has a wide range of applications.

Description

Technical Field

[0001] This invention relates to a method for correcting hydrogen isotope ratios, and more particularly to a method for correcting hydrogen isotope ratios in water samples obtained by adsorption. Background Technology

[0002] Hydrogen has three isotopes: protium, deuterium, and tritium. By studying the ratio of hydrogen isotopes in various hydrogen-containing substances, we can help people study scientific laws, deepen their understanding of meteorology, environment, energy and other fields, and thus lay the necessary foundation for human beings to understand, utilize and transform nature.

[0003] Currently, hydrogen isotope ratio testing often uses liquid water as the sample. Water in the gas generally needs to be collected as liquid water before testing, while other hydrogen-containing substances must first be converted into water before being collected as liquid water for testing. Adsorption is an important method for obtaining water samples. This method first uses a water adsorbent to adsorb water vapor from the gas, and then desorbs it to obtain the water sample. The choice of water adsorbent is crucial in this process.

[0004] Based on different water adsorption principles, water adsorbents can be divided into physical water adsorbents and chemical water adsorbents. For physical water adsorbents, most contain a large number of hydrogen-containing groups. During water desorption, these hydrogen-containing groups easily enter the water, thus affecting the test results of the hydrogen isotope ratio in the water sample. Furthermore, since the degree of desorption of water and hydrogen-containing groups is greatly affected by desorption conditions, the hydrogen isotope ratio of the sample is often difficult to effectively correct. For chemical water adsorbents, high-purity chemical water adsorbents are often selected. These adsorbents themselves do not contain hydrogen-containing groups and do not affect the hydrogen isotope ratio of the sample. However, high-purity chemical water adsorbents are often very expensive, costing tens or even hundreds of times more than industrial-grade chemical water adsorbents, resulting in high operating costs. While industrial-grade chemical water adsorbents are inexpensive, their low purity and presence of a certain amount of hydrogen-containing groups affect the test results of the hydrogen isotope ratio in the sample, causing deviations in the test results. Summary of the Invention

[0005] The purpose of this invention is to provide a method for correcting the hydrogen isotope ratio of water samples obtained by adsorption, which solves the technical problems of high cost of existing high-purity chemical water adsorbents and deviation of hydrogen isotope ratio test results caused by physical water adsorbents and industrial chemical water adsorbents.

[0006] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0007] A method for correcting the hydrogen isotope ratio of water samples obtained by adsorption, characterized by the following steps:

[0008] Step 1: Multiple sets of industrial chemical water adsorbents are used to adsorb known water samples. After sufficient desorption, multiple sets of water samples are obtained, and known parameters are recorded. Then, the hydrogen isotope ratio of each set of water samples is measured. The known parameters include the mass of each set of industrial chemical water adsorbents, the hydrogen isotope ratio of the known water samples, and the mass of each set of water samples.

[0009] Step 2: Construct a correction formula, transform the correction formula to extract the horizontal axis parameter formula, substitute the known parameters recorded in Step 1 into the horizontal axis parameter formula to calculate the horizontal axis parameters, use the hydrogen isotope ratio of each group of water samples obtained in Step 1 as the vertical axis parameter to plot the graph, then perform linear fitting to obtain the fitted line, and finally update the correction formula by combining the slope and intercept of the fitted line to obtain the updated correction formula.

[0010] Step 3: Adsorb the water sample to be tested using an industrial chemical water adsorbent. After sufficient desorption, the water sample to be tested is obtained, and the test parameters are recorded. Then, the hydrogen isotope ratio of the water sample to be tested is measured. The test parameters include the mass of the industrial chemical water adsorbent used to adsorb the water sample to be tested and the mass of the water sample to be tested.

[0011] Step 4: Substitute the test parameters from Step 3 and the hydrogen isotope ratio of the water sample to be tested into the updated correction formula from Step 2 to calculate the corrected hydrogen isotope ratio of the water sample to be tested.

[0012] Furthermore, step 1 specifically includes:

[0013] 1.1) Use multiple sets of industrial chemical water adsorbents of different masses to adsorb known water samples with the same hydrogen isotope ratio; or, use multiple sets of industrial chemical water adsorbents of the same mass to adsorb known water samples with different hydrogen isotope ratios; or, use multiple sets of industrial chemical water adsorbents of different masses to adsorb known water samples with different hydrogen isotope ratios.

[0014] 1.2) After fully desorbing the adsorbed multiple groups of known water samples, the corresponding water samples were obtained and the known parameters were recorded. Then, the hydrogen isotope ratio of each group of water samples was measured. The known parameters include the mass of each group of industrial chemical water adsorbent, the hydrogen isotope ratio of the known water samples, and the mass of each group of water samples.

[0015] Furthermore, in step 1.1), there are no fewer than 3 known water samples.

[0016] Further, in step 1.1), the known water sample is liquid water or water vapor with a known hydrogen isotope ratio.

[0017] Furthermore, in step 2, the correction formula is obtained based on element balance, and its expression is as follows:

[0018] ;

[0019] In the formula, m0 represents the mass of the industrial chemical water adsorbent; x represents the percentage of hydrogen atoms per gram of industrial chemical water adsorbent; M H R0 represents the molar mass of a hydrogen atom; R0 represents the hydrogen isotope ratio of hydrogen atoms in industrial chemical water adsorbents; m w Indicates the mass of the desorbed water sample; M w R represents the molar mass of water; w R1 represents the hydrogen isotope ratio of the water sample before adsorption; R2 represents the hydrogen isotope ratio of the water sample after desorption.

[0020] Furthermore, in step 2, the correction formula is transformed as follows:

[0021] ;

[0022] The formula for the horizontal axis parameter is: .

[0023] Further, in step 2, the step of updating the correction formula by combining the slope and intercept of the fitted line specifically involves taking the reciprocal of the slope of the fitted line as the proportion of hydrogen atoms in each gram of industrial chemical water adsorbent, taking the intercept of the fitted line as the hydrogen isotope ratio of hydrogen atoms in the industrial chemical water adsorbent, substituting them into the correction formula and transforming it to obtain the updated correction formula.

[0024] Furthermore, in step 2, the updated correction formula is:

[0025] ;

[0026] In the formula, It is the reciprocal of the slope of the fitted line; This is the intercept of the fitted line.

[0027] Furthermore, the industrial chemical water adsorbent mentioned in step 3 is the same model and batch as the industrial chemical water adsorbent mentioned in step 1.

[0028] Furthermore, in step 3, the water sample to be tested is water vapor.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. The present invention provides a method for correcting the hydrogen isotope ratio of water samples obtained by adsorption. The method updates the correction formula based on the known parameters of the water sample and substitutes the relevant parameters of the water sample to be tested into the updated correction formula to obtain the corrected hydrogen isotope ratio of the water sample. The corrected hydrogen isotope ratio is consistent with the true value within the uncertainty range. The influence of the adsorption collection process on the hydrogen isotope ratio of the water sample using this method is negligible. The correction effect is good. Compared with the case without correction, the deviation of the hydrogen isotope ratio test results is significantly reduced.

[0031] 2. The present invention provides a method for correcting the hydrogen isotope ratio of water samples obtained by adsorption. The water sample is obtained by using an industrial chemical water adsorbent. The cost of the water adsorbent material is reduced to a fraction to a fraction of that of using a high-purity chemical water adsorbent, which can significantly reduce material costs and testing costs.

[0032] 3. In the method for correcting the hydrogen isotope ratio of water samples obtained by adsorption provided by the present invention, the number of groups of known water samples measured shall not be less than 3, and the industrial chemical water adsorbent used for adsorbing the known water samples and the water samples to be tested shall be of the same type and batch, so as to ensure the accuracy of the correction results.

[0033] 4. The hydrogen isotope ratio correction method for water samples obtained by adsorption provided by this invention can be used for the correction of both deuterium and tritium content; it can be used for the correction of both deuterium-poor and deuterium-rich (tritium) samples, and has a wide range of applications.

[0034] 5. The present invention provides a method for correcting the hydrogen isotope ratio of water samples obtained by adsorption. The operation steps and process are simple and the requirements for the professional skills of the operators are low.

[0035] 6. The present invention provides a method for correcting the hydrogen isotope ratio of water samples obtained by adsorption. After obtaining the correction value once, the value can be used for a long time, and other costs or expenses are relatively reduced. Attached Figure Description

[0036] Figure 1 This is a schematic flowchart of a method for correcting the hydrogen isotope ratio of water samples obtained by adsorption according to the present invention. Detailed Implementation

[0037] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0038] like Figure 1 As shown, this embodiment provides a method for correcting the hydrogen isotope ratio of water samples obtained by adsorption, including the following steps:

[0039] Step 1: Use multiple sets of industrial chemical water adsorbents to adsorb known water samples. After sufficient desorption, obtain multiple sets of water samples and record the known parameters. Then measure the hydrogen isotope ratio of each set of water samples.

[0040] Specifically: 1.1) Multiple sets of industrial chemical water adsorbents of different masses are used to adsorb known water samples with the same hydrogen isotope ratio; or, multiple sets of industrial chemical water adsorbents of the same mass are used to adsorb known water samples with different hydrogen isotope ratios; or, multiple sets of industrial chemical water adsorbents of different masses are used to adsorb known water samples with different hydrogen isotope ratios. To ensure the accuracy of the fitting results, in this embodiment, there are no fewer than 3 sets of known water samples, and the preferred scheme is no fewer than 5 sets. The known water samples can be liquid water or water vapor with known hydrogen isotope ratios.

[0041] 1.2) After fully desorbing the adsorbed multiple groups of known water samples, the corresponding water samples were obtained and the known parameters were recorded. Then, the hydrogen isotope ratio of each group of water samples was measured.

[0042] The known parameters described in this embodiment include the mass of each group of industrial chemical water adsorbent, the known hydrogen isotope ratio of the water sample, and the mass of each water sample. During the desorption process, a humidity sensor is used to monitor the partial pressure of water vapor in real time; when the humidity sensor detects no moisture, it indicates that desorption is complete.

[0043] Step 2: Construct the correction formula, transform the correction formula to extract the horizontal axis parameter formula, and then substitute the known parameters recorded in Step 1 into the horizontal axis parameter formula to calculate the horizontal axis parameters. Use the hydrogen isotope ratio of each group of water samples obtained in Step 1 as the vertical axis parameter to plot the graph. Then perform linear fitting to obtain the fitted line. Finally, combine the slope and intercept of the fitted line to update the correction formula and obtain the updated correction formula.

[0044] The correction formula in this embodiment is based on elemental balance. Industrial chemical water adsorbents contain some hydrogen, which can fully exchange with the hydrogen in the adsorbed water to reach equilibrium. Based on elemental balance, the total amount of deuterium (or tritium) and protium remains unchanged before and after adsorption. Therefore, the expression for the correction formula is as follows:

[0045] ;

[0046] In the formula, m0 represents the mass of the industrial chemical water adsorbent (g); x represents the percentage of hydrogen atoms per gram of the industrial chemical water adsorbent (g / g); M H R0 represents the molar mass of a hydrogen atom, in g / mol; R0 represents the hydrogen isotope ratio of hydrogen atoms in industrial chemical water adsorbents, a dimensionless quantity; m wThe mass of the desorbed water sample is expressed in grams (g); M w R represents the molar mass of water, in g / mol. w R1 represents the hydrogen isotope ratio of the water sample before adsorption, a dimensionless quantity; R2 represents the hydrogen isotope ratio of the water sample after desorption, a dimensionless quantity.

[0047] The corrected formula, after transformation, is:

[0048]

[0049] From the above-described modified correction formula, it can be seen that... and The linear relationship is satisfied, therefore... The formula for the x-axis parameter is used, and then the corresponding x-axis parameter is calculated by combining it with the known parameters. After that, the x-axis parameter is... Plot the graph and perform a line fit.

[0050] The specific steps for updating the correction formula using the slope and intercept of the fitted straight line in this embodiment are as follows: The reciprocal of the slope of the fitted straight line is taken as the proportion of hydrogen atoms per gram of industrial chemical water adsorbent; the intercept of the fitted straight line is taken as the hydrogen isotope ratio of hydrogen atoms in the industrial chemical water adsorbent. These values ​​are then substituted into the correction formula and transformed to obtain the updated correction formula. The updated correction formula is as follows:

[0051]

[0052] In the formula, The reciprocal of the slope of the fitted straight line is used to replace the percentage of hydrogen atoms per gram of industrial chemical water adsorbent in the correction formula. The intercept of the fitted straight line is replaced by the hydrogen isotope ratio of hydrogen atoms in the industrial chemical water adsorbent in the correction formula.

[0053] Step 3: Adsorb the water sample to be tested using an industrial chemical water adsorbent. After sufficient desorption, the water sample (water vapor) to be tested is obtained, and the test parameters are recorded. Then, the hydrogen isotope ratio of the water sample to be tested is measured.

[0054] The industrial chemical water adsorbent used in this step is the same model and batch as the industrial chemical water adsorbent used in step 1. The test parameters include the mass of the industrial chemical water adsorbent adsorbing the water sample and the mass of the water sample itself.

[0055] Step 4: Substitute the test parameters from Step 3 and the hydrogen isotope ratio of the water sample to be tested into the updated correction formula from Step 2 to calculate the corrected hydrogen isotope ratio of the water sample to be tested.

[0056] In this embodiment, five water adsorption columns containing granular anhydrous calcium chloride (an industrial chemical water adsorbent) were used to adsorb five water samples with different deuterium contents. After that, the water adsorbed by the water adsorption columns was fully desorbed, and the mass of the water sample after desorption was weighed. The deuterium content of the water sample before adsorption and after desorption was measured. The results are shown in Table 1.

[0057] Table 1 shows the experimental results for five groups.

[0058]

[0059] Substitute the measured results of any four groups of experiments into the formula for the horizontal axis parameter. The obtained value is used as the x-axis parameter, and the deuterium content of the corresponding desorbed water sample is used as the y-axis parameter to plot the graph. A linear fit is then performed to obtain the fitted line. The reciprocal of the slope of the fitted line is then used... The hydrogen content per gram of industrial chemical water adsorbent is expressed as the intercept. As the hydrogen isotope ratio in industrial chemical water adsorbents, the correction formula was updated to obtain the updated correction formula. Finally, the measured results of another set of experiments were substituted into the updated correction formula to calculate the corrected hydrogen isotope ratio of the sample. The comparison between the corrected and uncorrected hydrogen isotope ratios is shown in Table 2.

[0060] Table 2 shows the effect of correction on the degree of deviation of deuterium content in the samples.

[0061]

[0062] As shown in Table 2, the deviation between the corrected hydrogen isotope ratio of the sample and the hydrogen isotope ratio of the water sample before adsorption is significantly reduced compared with that before correction. The corrected hydrogen isotope ratio of the sample is consistent with that of the water sample before adsorption within the measurement uncertainty range (0.5%).

[0063] Furthermore, this invention can obtain high-precision hydrogen isotope ratio values ​​for water samples using industrial chemical water adsorbents, reducing the material cost of the water adsorbent to a fraction of that of using high-purity chemical water adsorbents, thus significantly lowering material costs. Simultaneously, once a calibration value is obtained, it can be used long-term, further reducing other expenses or costs.

[0064] In summary, this invention effectively solves the problems of high cost of existing high-purity chemical water adsorbents and deviations in hydrogen isotope ratio test results caused by physical water adsorbents and industrial chemical water adsorbents.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for correcting the hydrogen isotope ratio of a water sample obtained by adsorption, characterized by, The method comprises the following steps: Step 1: a plurality of groups of industrial chemical water adsorbents are used to adsorb known water samples respectively, a plurality of groups of water samples are obtained after sufficient desorption, and known parameters are recorded, and then the hydrogen isotope ratio of each group of water samples is measured; the known parameters include the mass of each group of industrial chemical water adsorbents, the hydrogen isotope ratio of the known water sample, and the mass of each group of water samples; Step 2: a correction formula is constructed, the correction formula is deformed to extract a horizontal coordinate parameter formula, the known parameters recorded in step 1 are substituted into the horizontal coordinate parameter formula to calculate the horizontal coordinate parameters, the hydrogen isotope ratio of each group of water samples obtained in step 1 is taken as the vertical coordinate parameter to draw a graph, then a fitting straight line is obtained through linear fitting, and finally the correction formula is updated combined with the slope and intercept of the fitting straight line to obtain an updated correction formula; Step 3: an industrial chemical water adsorbent is used to adsorb a water sample to be tested, a water sample to be tested is obtained after sufficient desorption, and test parameters are recorded, and then the hydrogen isotope ratio of the water sample to be tested is measured; the test parameters include the mass of the industrial chemical water adsorbent for adsorbing the water sample to be tested and the mass of the water sample to be tested; Step 4: the test parameters of step 3 and the hydrogen isotope ratio of the water sample to be tested are substituted into the updated correction formula of step 2 to calculate the corrected hydrogen isotope ratio of the water sample to be tested.

2. The method for correcting the hydrogen isotope ratio of a water sample obtained by adsorption according to claim 1, characterized by, Step 1 is specifically: 1.1) a plurality of groups of industrial chemical water adsorbents with different masses are used to adsorb known water samples with the same hydrogen isotope ratio respectively; or, a plurality of groups of industrial chemical water adsorbents with the same mass are used to adsorb known water samples with different hydrogen isotope ratios respectively; or, a plurality of groups of industrial chemical water adsorbents with different masses are used to adsorb known water samples with different hydrogen isotope ratios respectively; 1.2) the adsorbed plurality of groups of known water samples are desorbed respectively to obtain corresponding water samples, and known parameters are recorded, and then the hydrogen isotope ratio of each group of water samples is measured; the known parameters include the mass of each group of industrial chemical water adsorbents, the hydrogen isotope ratio of the known water sample, and the mass of each group of water samples.

3. The method for correcting the hydrogen isotope ratio of a water sample obtained by adsorption according to claim 2, characterized by, In step 1.1), the known water samples are not less than 3 groups.

4. The method for correcting the hydrogen isotope ratio of a water sample obtained by adsorption according to claim 3, characterized by, In step 1.1), the known water samples are liquid water or water vapor with known hydrogen isotope ratios.

5. The correction method for the hydrogen isotope ratio of the water sample obtained by adsorption according to claim 1, characterized in that: In step 2, the correction formula is obtained based on element balance, and the expression is as follows: ； In the formula, m0 represents the mass of the industrial chemical water adsorbent; x represents the proportion of hydrogen atoms in each gram of the industrial chemical water adsorbent; M H represents the molar mass of hydrogen atoms; R0 represents the hydrogen isotope ratio of hydrogen atoms in the industrial chemical water adsorbent; m w represents the mass of the water sample desorbed; M w represents the molar mass of water; R w represents the hydrogen isotope ratio of the water sample before adsorption; R1 represents the hydrogen isotope ratio of the water sample measured after desorption.

6. The correction method for the hydrogen isotope ratio of the water sample obtained by adsorption according to claim 5, characterized in that: In step 2, the correction formula is deformed to: ； The abscissa parameter formula is: .

7. The correction method for the hydrogen isotope ratio of the water sample obtained by adsorption according to claim 6, characterized in that: In step 2, the correction formula is deformed to:

8. The method of claim 7, wherein: In step 2, the updated correction formula is: ； wherein is the inverse of the slope of the fitted straight line; is the intercept of the fitted straight line.

9. The method of claim 1, wherein: In step 3, the industrial chemical water adsorbent is the same model and batch as the industrial chemical water adsorbent of step 1.

10. The method of claim 9, wherein: In step 3, the water sample to be measured is water vapor.

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