A solid hydrogen isotope calibration material and preparation method thereof
By preparing solid hydrogen isotope standards in an inert gas glove box and utilizing chemical reaction kinetics and the principle of element conservation, the problem of insufficient stability of liquid isotope water was solved, providing highly stable standards suitable for deep space exploration, achieving easier storage and transportation, and improving the accuracy of experimental data.
Patent Information
- Application Number
- CN202411824650.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2044-12-12
AI Technical Summary
Existing liquid standard isotope water is not stable enough during storage and use, and is easily affected by external environmental factors, resulting in errors in isotope ratio measurement. In addition, the demand for isotope calibration materials for deep space exploration missions is not met.
By adopting the principles of chemical reaction kinetics and element conservation, solid hydrogen isotope standards are prepared in an inert gas glove box. High-purity anhydrous copper sulfate and high-purity sodium oxide are used for chemical reaction to prepare copper hydroxide standards with the morphology of long strip crystals, ensuring a single and stable source of hydrogen elements.
It provides a simpler storage and transportation method, improves the stability of the calibration object, reduces the influence of external environmental factors, ensures the accuracy of experimental data, and is suitable for deep space exploration missions.
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Figure CN119935668B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of isotope calibration material preparation, in particular to a solid hydrogen isotope calibration material and a preparation method thereof. Background Art
[0002] In existing technologies, hydrogen isotope calibration materials mainly use liquid standard isotope water as a reference material. However, this calibration material has significant technical drawbacks during storage and use. First, the storage requirements of liquid standard isotope water are strict, requiring specific containers and precise temperature and pressure control to prevent isotope fractionation and water vapor escape. Second, during phase transition processes (e.g., from liquid to gaseous state) and experiments under high vacuum conditions, liquid standard isotope water is not stable enough and is easily affected by external environmental factors, resulting in measurement errors of isotope ratios.
[0003] Currently, the preparation technology for solid hydrogen isotope standards has not yet been developed, and this field remains largely unexplored. Solid hydrogen isotope standards are expected to offer the following technical advantages: first, easier storage and transportation, eliminating the need for complex temperature control systems; second, greater stability, reducing the impact of external environmental factors on isotope ratios, thereby improving the accuracy of experimental data.
[0004] Furthermore, there is currently no dedicated technical research or product development for isotope calibration materials required for deep space exploration environments. Deep space exploration missions place even more stringent demands on isotope calibration materials, requiring them to remain stable in extreme temperature, pressure, and radiation environments. Therefore, researching and developing isotope calibration technologies suitable for deep space exploration is crucial to ensuring the accuracy and reliability of exploration data.
[0005] To overcome the shortcomings of existing technologies, this invention aims to provide the following technical solutions: first, developing a novel method for preparing solid hydrogen isotope standards to meet the needs of diverse experimental environments; second, studying the stability of solid hydrogen isotope standards in extreme environments to provide a stable isotope calibration method for deep space exploration missions; and third, exploring a new isotope calibration method suitable for deep space exploration to promote the development of deep space exploration technology. The implementation of this invention is expected to fill the gap in solid hydrogen isotope standard preparation technology and provide important technical support for the field of deep space exploration. Summary of the Invention
[0006] One of the purposes of the present invention is to solve the problems mentioned in the above-mentioned background technology, and proposes a method for preparing solid hydrogen isotope calibration materials based on chemical reaction kinetics, thermal stability of materials and conservation of elements. It is mainly used in the field of deep space exploration engineering tests that require a fixed hydrogen isotope ratio for simulated water-containing lunar soil, and is used for equivalent experiments and ground or space calibration of deep space exploration payloads.
[0007] To achieve the above object, the present invention adopts the following technical solution: a method for preparing a solid hydrogen isotope standard, specifically comprising the following steps:
[0008] S1. In a glove box, dissolve high-purity anhydrous copper sulfate in deionized water to a concentration of 0.1-0.3 mol / L, then add high-purity Na2O in small amounts and multiple times until no new precipitate is precipitated, to obtain a mixed reaction solution;
[0009] S2. Filter the mixed reaction solution in a glove box, wash the filter residue with anhydrous ethanol, dry it, and store it in a sealed container to obtain a calibration substance precipitate.
[0010] As a further improvement of the preparation method of solid hydrogen isotope standard:
[0011] Preferably, the high-purity Na2O contains 80 wt% pure sodium oxide and 20 wt% sodium peroxide, and the mass ratio of high-purity anhydrous copper sulfate to high-purity Na2O is (2-2.5):1.
[0012] Preferably, the purity of the high-purity anhydrous copper sulfate is analytically pure, and the high-purity anhydrous copper sulfate is dissolved in deionized water and stirred using a magnetic stirrer for 10-15 minutes.
[0013] Preferably, the high-purity Na2O, high-purity anhydrous copper sulfate, weighing device, dissolving device and filtering device used in steps S1 and S2 are placed in a transition chamber of the glove box for vacuum degassing before use.
[0014] Preferably, the heat-resistant device is subjected to high-temperature vacuum degassing in the transition chamber of the glove box, and the non-heat-resistant device is subjected to natural vacuum degassing.
[0015] Preferably, the temperature of high-temperature vacuum degassing is greater than 150-200°C, the degassing time is greater than 12-24 hours, the time of natural vacuum degassing is 1 to 2 days, and the temperature of natural vacuum degassing is 20-40°C.
[0016] Preferably, when high-purity Na2O and high-purity anhydrous copper sulfate are vacuum degassed in the glove box transition chamber, the bottle mouths containing the reagents are equipped with stainless steel metal mesh to avoid contaminating the glove box transition chamber.
[0017] Preferably, the mixed reaction solution is filtered in step S2 by suction filtration, and precursor deionized water or anhydrous ethanol is used to assist the filtration during the filtration process.
[0018] Preferably, the calibration material in step S2 is precipitated in an inert gas atmosphere in a glove box, bottled, and sealed for storage.
[0019] A second object of the present invention is to provide a solid hydrogen isotope standard prepared by the preparation method of any one of the above-mentioned solid hydrogen isotope standards.
[0020] The beneficial effects of the present invention compared to the prior art are:
[0021] 1) The present invention provides a method for preparing a solid hydrogen isotope standard based on chemical reaction kinetics, thermal stability of substances, and conservation of elements. A simple synthetic route is used to prepare a solid hydrogen isotope standard with the same isotope ratio as isotope standard water. The synthesis principle mainly refers to the chemical formula:
[0022] CuSO4+2NaOH=Cu(OH)2↓+Na2SO4
[0023] During the synthesis process, the principle that the chemical reaction rate is much greater than the physical thermal fractionation is utilized, and the source of hydrogen is strictly controlled by the conservation of elements. The copper source comes from anhydrous copper sulfate, the alkali source comes from high-purity sodium oxide, and all hydrogen sources come from liquid water. Physical water is converted into chemical water, and the thermal stability of the calibration material is improved through the action of chemical bonds. Finally, the hydrogen isotope solid calibration material is prepared.
[0024] To ensure that all hydrogen was derived from the precursor deionized water, analytically pure anhydrous copper sulfate and high-purity sodium oxide (containing 20% sodium peroxide as an impurity) were used as reactants. All experimental instruments and required chemicals were operated in an inert gas glove box, and opened and used within the inert gas glove box. All equipment that could absorb moisture from the air was degassed according to the vacuum manual.
[0025] In the traditional industrial copper hydroxide preparation method, air is not isolated, the sources of hydrogen elements are diverse and cannot be traced, and the isotopes of the water produced by heating are uncertain, making it difficult to use as a solid hydrogen isotope calibrant.
[0026] 2) SEM images show that the solid hydrogen isotope calibration material prepared by the present invention is mainly composed of long strips of crystals. XRD analysis shows that the main phase of the calibration material crystals is copper hydroxide, and the remaining peaks have no obvious corresponding components.
[0027] To ensure high sample purity, an inert atmosphere was maintained in the glove box. Sodium oxide was added in small, repeated additions. Adding sodium oxide too quickly could result in locally high pH values and reduce the concentration of the copper hydroxide product. Anhydrous ethanol was used to wash the filter residue to further reduce the exchange of hydrogen isotopes between the product and water. Similarly, the sample was low-temperature dried in the glove box.
[0028] The calibration material has a high water content (theoretical water content reaches 18% wt). XRD data indicates high purity, with copper hydroxide as the primary crystalline phase. SEM images show well-crystallized samples, and vacuum thermogravimetric analysis demonstrates excellent thermal stability. Isotopic values (4‰, -74‰, and -24‰) were measured using the sample seven days after sealing. The results indicate that the sample has not deteriorated in the sealed state and remains capable of calibration. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 is an X-ray diffraction (XRD) pattern of the solid hydrogen isotope standard prepared in Example 1 of the present invention;
[0030] Figure 2 This is a scanning electron microscope (SEM) image of the solid hydrogen isotope standard prepared in Example 1 of the present invention;
[0031] Figure 3 This is a vacuum thermogravimetric analysis (VTG) diagram of the solid hydrogen isotope standard prepared in Example 1 of the present invention;
[0032] Figure 4 Figures 1 and 2 show the isotope calibration results (after 7 days of storage) of the solid hydrogen isotope standard prepared in Example 1 of the present invention. The upper and lower panels (a), (b), and (c) represent the pressure values (upper panel) and isotope values (lower panel) of the solid standard prepared from precursor water with hydrogen isotope contents of 4‰, -74‰, and -24‰, respectively.
[0033] Figure 5 is a schematic diagram of the calibration spectrum equipment;
[0034] Figure 6 This is the isotope calibration result of commercial analytical grade copper hydroxide. DETAILED DESCRIPTION
[0035] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention.
[0036] Example 1
[0037] This embodiment provides a method for preparing a solid hydrogen isotope standard, comprising the following steps:
[0038] S1. In a glove box, open the bottles of high-purity Na2O (80% purity, containing 20% sodium peroxide) and high-purity anhydrous copper sulfate (analytical grade), cover the bottles with a layer of metal mesh (to prevent drug dust), and degas in a transition chamber of the glove box at 100°C under vacuum for 8 hours;
[0039] The weighing device, dissolving device and filtering device are placed in the transition chamber of the glove box for vacuum degassing before use; the heat-resistant device is subjected to high-temperature vacuum degassing (170°C, 12h degassing), and the non-heat-resistant device is subjected to natural vacuum degassing (1-2 days);
[0040] S2. In a glove box, 3.2 g of high-purity anhydrous copper sulfate was dissolved in 100 ml of deionized water to a concentration of 0.2 mol / L. The mixture was magnetically stirred for 10 min, and then high-purity Na2O was added in small amounts and multiple times. The mass ratio of high-purity anhydrous copper sulfate to high-purity Na2O was 2.5:1. The addition was stopped until no new precipitate was precipitated to obtain a mixed reaction solution.
[0041] S2. Filter the mixed reaction solution in a glove box, wash the filtered material with anhydrous ethanol and then dry it, seal it with a stopper, and place it on a semiconductor refrigeration chip for low-temperature storage, thereby obtaining the calibration material precipitate 1 for use.
[0042] Example 2
[0043] This embodiment provides a method for preparing a solid hydrogen isotope standard. The specific steps are similar to those of Example 1, except that in step S2, 1.6 g of high-purity anhydrous copper sulfate is dissolved in 100 ml of deionized water at a concentration of 0.1 mol / L to obtain a standard precipitate 2 for later use.
[0044] Example 3
[0045] This embodiment provides a method for preparing a solid hydrogen isotope standard. The specific steps are similar to those in Example 1, except that in step S2, 4.8 g of high-purity anhydrous copper sulfate is dissolved in 100 ml of deionized water at a concentration of 0.3 mol / L to obtain a standard precipitate 3 for use.
[0046] Example 4
[0047] This embodiment provides a method for preparing a solid hydrogen isotope standard. The specific steps are similar to those of Example 1, except that the mass ratio of high-purity anhydrous copper sulfate to high-purity Na2O is 2:1, and a standard precipitate 4 is prepared for use.
[0048] Figure 1 The X-ray diffraction (XRD) pattern of the calibration material precipitate prepared in Example 1; Figure 1 The specific test steps are as follows: the calibration material precipitate prepared in Example 1 is placed on the sample stage of the X-ray diffractometer, and the scanning angle is 20-80°. Figure 1 It can be seen that the main component of the calibration precipitate prepared in Example 1 is copper hydroxide and does not contain other obvious impurities. It should be noted that this substance is easily deteriorated by combining with carbon dioxide and needs to be sealed and stored and used immediately after opening.
[0049] Figure 2 This is a scanning electron microscope (SEM) image of the calibration material precipitate prepared in Example 1; Figure 2 The specific test steps are as follows: the calibration material prepared in Example 1 is precipitated and spread on weighing paper, a cotton swab is used to pick up the sample, the conductive adhesive is stuck on the sample table, the peeling paper is carefully removed, and the sample on the cotton swab is shaken off onto the conductive adhesive, and a scanning electron microscope test is performed. Figure 2 It can be seen that the crystallization of the calibration material precipitate obtained in Example 1 is good, and the calibration material precipitate is almost uniformly long and narrow crystals. The calibration material obtained by this process has good crystal consistency.
[0050] Figure 3 This is a vacuum thermogravimetric analysis diagram of the calibration material precipitate obtained in Example 1; Figure 3 The specific test steps are as follows: the calibration material prepared in Example 1 is placed in the sample chamber, the gas in the sample chamber is evacuated using a vacuum pump, the temperature is raised at a rate of 1°C / min, and the temperature is maintained at 25, 50, and 70°C for 20 minutes each, and then heated to 150°C. Figure 3 It can be seen that the calibration material precipitate prepared in Example 1 has good thermal stability under vacuum, with a thermal decomposition temperature of about 100°C, and accelerated decomposition under high humidity conditions of around 140°C, indicating that the sample has vacuum thermal stability and can work in a vacuum environment, overcoming the shortcomings of traditional liquid calibration materials.
[0051] Figure 4 Figure 1 shows the isotope test results of the calibration material prepared in Example 1 after being precipitated for 7 days. There are three groups of graphs (a), (b), and (c), representing the solid calibration materials prepared from precursor water with hydrogen isotope contents of 4‰, -74‰, and -24‰, respectively. The upper graph represents the pressure value and the lower graph represents the isotope value. Figure 4 The specific test steps are to place the sample in the calibration container, remove the gas, heat the calibration (greater than 100℃), start recording the spectrum data when the vacuum gauge reading reaches 150Pa, and end the recording when the vacuum gauge reading reaches 250Pa. Figure 4 It can be seen that the calibration material prepared in Example 1 can be resealed and stored after being opened, and its isotope value will not change over time.
[0052] Isotope calibration:
[0053] The D / H value was tested using the calibration material precipitate and deionized water sample prepared in Example 1, and the spectral equipment was calibrated as shown in the attached Figure 5 As shown, the calibration steps are as follows:
[0054] S1. Keep all valves closed, open valve 1 and valve 2, and continue exhausting the entire equipment at 35°C for 12 hours;
[0055] S2, close valve 1 and heat the gas calibration component containing the calibration material;
[0056] S3: Start recording spectrum data when the vacuum gauge reading reaches 150Pa and stop recording when the reading reaches 250Pa;
[0057] S4. Analyze the gas isotope values to see if they are consistent with the water isotopes of the synthetic calibration material. If they are consistent, it means that chemical reaction kinetics and element conservation can be used to retain the water isotopes in the solid calibration material before physical fractionation.
[0058] Similarly, use Figure 5 The calibration spectrometer was used to perform the above hydrogen isotope value test on analytical pure copper hydroxide. Two samples were selected from a batch of analytical pure copper hydroxide. The test results are as follows: Figure 6 shown.
[0059] Similarly, use Figure 5 The solid hydrogen isotope calibration materials prepared in Example 2, Example 3 and Example 4 were subjected to the above hydrogen isotope value test using a calibration spectrum device.
[0060] Figure 5 It can be seen that the solid hydrogen isotope standard prepared by the present invention is consistent with the water isotope of the synthetic standard, indicating that the use of chemical reaction kinetics and element conservation can precede physical fractionation to retain the isotope of water in the solid hydrogen isotope standard prepared in Example 1. The current liquid isotope tester is not suitable for solid standards and needs to be calibrated using the existing hydrogen isotope spectrum. Due to the concentration-dependent effect, the gas pressure should be maintained at around 200 Pa. Compared with traditional liquid standards, the solid hydrogen isotope standard prepared by the present invention can be resealed and stored after opening, and will not undergo phase change fractionation over time. The calibration process does not require complex quantitative sampling equipment, can withstand high vacuum environments, and does not require nitrogen blowing.
[0061] Figure 6 While commercial analytical-grade copper hydroxide (CAG) maintains high purity, its hydrogen isotope composition is unknown. The hydrogen isotope composition of samples from the same batch varies by approximately 50‰, making it unsuitable for use as a hydrogen isotope standard. This suggests that when preparing solid hydrogen isotope standards for copper hydroxide, it is crucial not only to ensure the high purity of the precipitate but also to ensure traceability of the hydrogen isotopes.
[0062] When the solid hydrogen isotope standards prepared in Examples 2, 3, and 4 were tested for hydrogen isotope values, the gas isotope values were consistent with the water isotopes of the synthetic standards, indicating that chemical reaction kinetics and element conservation can be used to retain water isotopes in the solid hydrogen isotope standards prepared in Examples 2-4 prior to physical fractionation.
[0063] Those skilled in the art will appreciate that the foregoing descriptions are merely specific embodiments of the present invention, and not exhaustive. It should be noted that numerous variations and modifications are possible for those skilled in the art, and all such variations and modifications that do not exceed the scope of the claims should be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a solid hydrogen isotope standard, characterized in that: The following steps are involved: S1. In a glove box, dissolve high-purity anhydrous copper sulfate in deionized water to a concentration of 0.1-0.3 mol / L, then add high-purity Na2O in small amounts and multiple times until no new precipitate is precipitated, to obtain a mixed reaction solution; the high-purity Na2O contains 80 wt% pure sodium oxide and 20 wt% sodium peroxide, and the mass ratio of high-purity anhydrous copper sulfate to high-purity Na2O is (2-2.5):1; the purity of the high-purity anhydrous copper sulfate is analytical grade, and the high-purity anhydrous copper sulfate is dissolved in deionized water and stirred with a magnetic stirrer for 10-15 minutes; S2. Filter the mixed reaction solution in a glove box, wash the filter residue with anhydrous ethanol, dry it, and store it in a sealed container to obtain a calibration substance precipitate.
2. The method for preparing a solid hydrogen isotope standard according to claim 1, characterized in that: The high-purity Na2O, high-purity anhydrous copper sulfate, weighing device, dissolving device and filtering device used in steps S1 and S2 are placed in the transition chamber of the glove box for vacuum degassing before use.
3. The method for preparing a solid hydrogen isotope standard according to claim 2, wherein: In the glove box transition chamber, high-temperature vacuum degassing is performed on heat-resistant devices, and natural vacuum degassing is performed on non-heat-resistant devices.
4. The method for preparing a solid hydrogen isotope standard according to claim 3, wherein: The temperature of high-temperature vacuum degassing is greater than 150-200 ℃, the degassing time is greater than 12-24 h, the time of natural vacuum degassing is 1-2 days, and the temperature of natural vacuum degassing is 20-40 ℃.
5. The method for preparing a solid hydrogen isotope standard according to claim 2, characterized in that: When high-purity Na2O and high-purity anhydrous copper sulfate are vacuum degassed in the glove box transition chamber, the bottle mouths containing the reagents are equipped with stainless steel metal mesh to avoid contaminating the glove box transition chamber.
6. The method for preparing a solid hydrogen isotope standard according to claim 1, wherein: The mixed reaction solution is filtered in step S2 by suction filtration, and precursor deionized water or anhydrous ethanol is used to assist the filtration during the filtration process.
7. The method for preparing a solid hydrogen isotope standard according to claim 1, wherein: The calibration material precipitated in step S2 is bottled and sealed for storage in an inert gas atmosphere in a glove box.