Preparation device of mercury isotope diluent

Abstract

The utility model provides a preparation device of a mercury isotope diluent. The preparation device of the mercury isotope diluent comprises a digestion unit, a reduction unit and an enrichment unit which are connected in sequence, the digestion unit comprises a digestion reactor, an oxidant storage container and an oxidant extraction device; the reduction unit comprises a reducing agent storage container, a digestion solution extraction device, a reducing agent extraction device and a gas-liquid separator; a strong oxidant is stored in the oxidant storage container; a reducing agent is stored in the reducing agent storage container; components in the digestion reactor, the digestion solution extraction device and the enrichment unit, which are in contact with mercury, are made of Teflon or borosilicate glass materials. The device disclosed by the utility model can be used for extracting high-concentration enriched 199Hg and 200Hg mercury from mercury-enriched fish meat through a digestion reaction and a reduction enrichment process so as to prepare a mercury isotope diluent.

Description

Technical Field

[0001] The utility model relates to the technical field of environmental science analysis and environmental detection, in particular to a preparation device for a mercury isotope diluent. Background Art

[0002] Mercury is a toxic and hazardous heavy metal element that is ubiquitous in nature. It can diffuse from emission sources or migrate long distances through atmospheric activity, depositing in other areas, leading to serious ecological and health risks. Due to its unique physical and chemical properties, mercury's biogeochemical cycles are extremely complex. Due to a lack of effective measurement techniques and methods, many of the processes of mercury's migration and transformation in the environment remain unclear. Effective research methods are urgently needed to provide technical support for reducing mercury emissions, controlling mercury pollution, and protecting ecological and human health.

[0003] In recent years, rapid improvements and developments in plasma mass spectrometry (ICP-MS) analysis methods and instrument precision have enabled the development of mercury isotope analysis methods, which have gradually matured and are now widely used in mercury isotope analysis of environmental samples. Currently, using state-of-the-art multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), mercury isotope measurement accuracy can generally reach ±0.1‰. Therefore, by measuring and analyzing the mercury isotope composition and ratios of environmental samples, it is possible to study the environmental transfer and transformation of mercury. Using isotope dilution mass spectrometry techniques and methods, adding a single mercury isotope, or a sample of a naturally abundant and unusually high mercury isotope, to an environmental sample as a mercury isotope diluent can alter the mercury isotope composition of the sample. By then measuring the isotope ratios of the environmental sample under various environmental conditions and processes, the migration and transformation of mercury in the environment can be traced and studied in great detail.

[0004] However, the preparation of mercury isotope diluents is extremely difficult. Traditional methods primarily utilize isotope separation and enrichment techniques to separate and enrich a single isotope of mercury from its other isotopes. This separation technique is extremely complex and requires extremely high levels of instrumentation and process technology, making it feasible only in countries with advanced nuclear industry technology. Because high-purity single mercury isotopes are primarily used in the nuclear power industry, strict export restrictions and bans in producing countries make obtaining them extremely difficult, significantly impacting and limiting research in the field of environmental mercury.

[0005] Currently, the preparation of mercury isotope diluents primarily relies on isotope separation and concentration techniques. These techniques utilize the extremely subtle mass differences between various isotopes of the same element to separate, concentrate, and produce mercury. These methods primarily include gas diffusion, centrifugation, and laser separation. Both gas diffusion and centrifugation are relatively mature, but the purity of the isotopes they produce depends on the sophistication and scale of their equipment. Laser separation, on the other hand, is a technique only a handful of technologically advanced and developed countries possess.

[0006] There are also chemical methods that can separate and enrich isotopes, but elements with the same number of protons and electrons share similar chemical properties, making separation extremely challenging. Therefore, mercury isotope separation and enrichment technology is extremely challenging, and only countries with developed nuclear industries and advanced nuclear technology can produce high-purity mercury isotopes. Utility Model Content

[0007] The utility model provides a device for preparing a mercury isotope diluent, which aims to solve the technical problem of difficulty in preparing the mercury isotope diluent in the background technology.

[0008] In order to achieve the above-mentioned object, the utility model provides a preparation device of a mercury isotope diluent, comprising a digestion unit, a reduction unit and an enrichment unit connected in sequence;

[0009] The digestion unit includes a digestion reactor, an oxidant storage container and an oxidant extraction device, wherein the oxidant extraction device can extract the solution or gas in the oxidant storage container into the digestion reactor, and the digestion reactor is provided with a stirrer;

[0010] The reduction unit includes a reducing agent storage container, a digestion liquid extraction device, a reducing agent extraction device and a gas-liquid separator. The digestion liquid extraction device can extract the solution or gas in the digestion reactor into the gas-liquid separator, and the reducing agent extraction device can extract the solution or gas in the reducing agent storage container into the gas-liquid separator.

[0011] The oxidant storage container stores a strong oxidant;

[0012] The reducing agent storage container stores a reducing agent;

[0013] The components of the digestion reactor, the digestion solution extraction device and the enrichment unit are all made of Teflon or borosilicate glass.

[0014] Preferably, the oxidant extraction device, the digestion solution extraction device and the reducing agent extraction device are all pipes provided with peristaltic pumps.

[0015] Preferably, the gas-liquid separator includes a gas-liquid separation tube and a waste liquid bottle, and the waste liquid bottle is connected to the liquid end of the gas-liquid separation tube.

[0016] Preferably, the enrichment unit includes a drying tube and a mercury enrichment tube, one end of the drying tube is connected to the gas end of the gas-liquid separation tube, and the other end of the drying tube is connected to the mercury enrichment tube, and a mercury adsorbent is provided in the mercury enrichment tube.

[0017] Preferably, the drying tube is provided with soda lime desiccant.

[0018] Preferably, the mercury adsorbent is modified activated carbon with a particle size of less than 1 mm, quartz sand gold-plated particles, or pure gold particles.

[0019] Preferably, the enrichment unit further comprises a three-way valve and an environmental sample pipe fitting, wherein the three-way valve is connected to the drying tube, the gas-liquid separator and the environmental sample pipe fitting.

[0020] Preferably, the strong oxidant can be concentrated nitric acid of process ultrapure or analytical grade, or concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 4:1, or aqua regia, or concentrated nitric acid, peroxide and perchloric acid in a volume ratio of 5:10:1, and the reducing agent is stannous chloride.

[0021] The preparation device of a mercury isotope diluent of the utility model has the following beneficial effects:

[0022] Through the digestion reaction and reduction collection process, high concentrations of 199 Hg and 200 Hg is extracted from fish meat and enriched in high concentrations 199 Hg and 200 Hg of mercury, extracting mercury isotope diluents, and applying them to trace the migration and transformation process of environmental mercury, thus providing a new, simple and effective mercury isotope diluent preparation technology for the research in the field of environmental mercury. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural schematic diagram of a preferred embodiment of a device for preparing a mercury isotope diluent according to the present invention;

[0024] in,

[0025] 11. Digestion reactor; 12. Oxidant storage container; 13. Oxidant extraction device; 111. Stirring bar;

[0026] 21. Reducing agent storage container; 22. Digestion liquid extraction device; 23. Reducing agent extraction device; 24. Gas-liquid separator;

[0027] 241. Gas-liquid separation tube; 242. Waste liquid bottle;

[0028] 31. Drying tube; 32. Mercury enrichment tube; 33. Three-way valve; 34. Environmental sample fittings. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0030] Aiming at the existing problems, the utility model provides a device for preparing a mercury isotope diluent.

[0031] In one embodiment, a device for preparing a mercury isotope diluent, such as Figure 1 As shown, it includes a digestion unit, a reduction unit and an enrichment unit connected in sequence;

[0032] The digestion unit includes a digestion reactor 11, an oxidant storage container 12, and an oxidant extraction device 13. The oxidant extraction device 13 can extract the solution or gas in the oxidant storage container 12 into the digestion reactor 11. The digestion reactor 11 is provided with a stirrer 111;

[0033] The reduction unit includes a reducing agent storage container 21, a digestion liquid extraction device 22, a reducing agent extraction device 23, and a gas-liquid separator 24. The digestion liquid extraction device 22 can extract the solution or gas in the digestion reactor 11 into the gas-liquid separator 24, and the reducing agent extraction device 23 can extract the solution or gas in the reducing agent storage container 21 into the gas-liquid separator 24;

[0034] The oxidant storage container 12 stores a strong oxidant, which can be concentrated nitric acid of process ultrapure or analytical purity, or concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 4:1, or aqua regia, or concentrated nitric acid, peroxygen solution and perchloric acid in a volume ratio of 5:10:1;

[0035] The reducing agent storage container 21 stores a reducing agent, which is stannous chloride with a concentration of 100-200 g / L;

[0036] The digestion reactor 11, the digestion solution extraction device 22 and the components in the enrichment unit are all made of Teflon or borosilicate glass.

[0037] The working principle of the device for extracting mercury isotopes is:

[0038] The oxidant is extracted into the digestion reactor 11 by the oxidant extraction device 13. Under the stirring of the magnetic stirrer, the oxidant reacts with the fish powder in the digestion reactor 11. After 3-10 hours of dissolution reaction, the mercury in the fish is completely oxidized into ionic mercury distributed in the oxidant solution.

[0039] After the digestion is completed, the digestion liquid extraction device 22 extracts the reacted digestion liquid into the gas-liquid separator 24, and the reducing agent extraction device 23 extracts the stannous chloride solution in the reduction storage container 21 into the gas-liquid separator 24. The digestion liquid is mixed with the stannous chloride solution. During the mixing process, the stannous chloride reduces the mercury ions in the digestion liquid into gaseous elemental mercury, and the gaseous mercury is then enriched by the enrichment unit or used directly.

[0040] Based on the above embodiment, in this embodiment, the oxidant extraction device 13 , the digestion liquid extraction device 22 , and the reducing agent extraction device 23 are all pipes equipped with peristaltic pumps.

[0041] The gas-liquid separator 24 includes a gas-liquid separation tube 241 and a waste liquid bottle 242. The waste liquid bottle 242 is connected to the liquid end of the gas-liquid separation tube 241.

[0042] As a further improvement of this embodiment, the enrichment unit includes a drying tube 31 and a mercury enrichment tube 32. One end of the drying tube 31 is connected to the gas end of the gas-liquid separation tube 241, and the other end of the drying tube 31 is connected to the mercury enrichment tube 32. A mercury adsorbent is provided in the mercury enrichment tube 32.

[0043] Soda lime desiccant is provided in the drying tube 31. The mercury adsorbent is modified activated carbon with a particle size of less than 1 mm, quartz sand gold-plated particles or pure gold particles.

[0044] After the gaseous elemental mercury evaporates from the mixed liquid, it passes through the drying tube 31 to remove moisture, and then passes through the mercury enrichment tube 32 to be enriched on the mercury adsorbent. The waste gas is discharged from the gas outlet, and the waste liquid is discharged from the bottom of the gas-liquid separator 24 into the waste liquid bottle 242.

[0045] When the prepared mercury isotope diluent needs to be used for environmental mercury research, it is only necessary to heat the mercury enrichment tube 32 to 450-800°C to desorb the mercury in the mercury enrichment tube 32, and then carry it out through the carrier gas and load it into the gas sample that needs to be traced for research. The desorbed mercury can also be loaded into an oxidant again to become a liquid mercury isotope diluent, and then added to the liquid sample that needs to be traced for research.

[0046] As a further improvement of this embodiment, the enrichment unit further includes a three-way valve 33 and an environmental sample pipe 34. The three-way valve 33 connects the drying pipe 31, the gas-liquid separator 24 and the environmental sample pipe 34.

[0047] The gaseous elemental mercury extracted from the gas-liquid separation tube 241 passes through the three-way valve 33 and can be directly added to the environmental sample that needs to be traced and studied through the environmental sample pipe 34.

[0048] A method for using the device for preparing a mercury isotope diluent according to the utility model comprises the following steps:

[0049] Step S1, sampling: slice the mercury-enriched fish and place it in a cold storage or refrigerator in a low-temperature environment below -10°C to prevent the fish from rotting and mercury from volatilizing and losing, waiting for the next step of processing.

[0050] Step S2, drying: 500-100 grams of fish fillets are placed in a Teflon tray, the fillets are spread flat on the tray surface, and placed in a freeze dryer for freeze drying; freeze drying can prevent the fish from rotting and mercury from volatilizing and losing during the drying process, while facilitating the grinding process in the next step.

[0051] Step S3, grinding: The freeze-dried fish meat is placed in an agate mortar and manually ground, or placed in an agate grinder and automatically mechanically ground, to grind the fish meat into a 50-100 mesh powder. Then, 0.5-2 grams of the ground fish meat powder is taken and its total mercury concentration is measured to obtain the total mercury dose for the subsequent preparation of the mercury isotope diluent.

[0052] Step S4, digestion: 0.1-1 g (accurate to 0.0001 g) of fish powder is weighed and placed into a digestion reactor 11. A strong oxidant is pumped into the digestion reactor. The fish powder is dissolved in the strong oxidant solution under stirring by a magnetic stirrer 111. After 3-10 hours of dissolution, the mercury in the fish is oxidized to ionic mercury and distributed in the strong oxidant solution.

[0053] Step S5, reduction: the digestion solution in the digestion reactor 11 and the reducing agent in the reducing agent storage container 21 are drawn into the gas-liquid separator 24 for mixing, and the mercury ions in the digestion solution are reduced to gaseous elemental mercury;

[0054] Step S6, enrichment: obtaining the prepared mercury isotope diluent in the enrichment unit.

[0055] Through the above steps, mercury in the fish meat can be extracted and enriched in the mercury enrichment tube 32, thereby preparing a mercury isotope diluent. The mass of the prepared mercury isotope diluent can be obtained based on the measured total mercury concentration in the fish meat and the weight of the digested fish meat.

[0056] The technology of this utility model has been successfully applied to the tracing and research of atmospheric mercury in the Ailao Mountain forest. As shown in Table 1, the mercury isotope diluent prepared by this utility model was added to the climate chamber of the Ailao Mountain forest. After it was mixed with the atmosphere in the climate chamber (mixing time was greater than 2 hours), 6 atmospheric samples were collected from the climate chamber and their mercury isotope ratios were measured by MC-ICP-MS. The results showed that the mercury isotope ratio of the atmospheric mercury in the climate chamber was 1.347. 199 Hg and 200 The average values ​​of Hg non-mass fractionation were 1.55‰ and 0.17‰, which were significantly higher than the mercury isotope ratios of the same species in the normal atmosphere of the Ailao Mountain forest ( 199 Hg and 200 The average Hg non-mass fractionation values ​​were -0.2‰ and -0.06‰, respectively. This result demonstrates that the mercury isotope diluent prepared by this utility model can significantly alter the isotope ratio of atmospheric mercury and can be applied to in-depth research on environmental processes such as atmospheric mercury migration and transformation, dry and wet deposition, and exchange and migration with land and vegetation. This utility model's technical method is effective and reliable in achieving the addition of high-purity single mercury isotopes.

[0057]

[0058] Table 1

[0059] The preparation device and preparation method of the mercury isotope diluent of the utility model have the following beneficial effects:

[0060] Through the digestion reaction and reduction collection process, high concentrations of 199 Hg and 200 Hg is extracted from fish meat and enriched in high concentrations 199 Hg and 200 Hg of mercury, extracting mercury isotope diluent, and applying it to trace the migration and transformation process of environmental mercury, thus providing a new, simple and effective mercury isotope diluent preparation device for the research in the field of environmental mercury.

[0061] Firstly, the utility model avoids the use of isotope separation technology that requires very high technical and industrial levels and has an extremely complex production process to prepare a single mercury isotope, and adopts a very simple physical and chemical method to prepare a mercury isotope diluent. The technical method is simple and the preparation process is relatively easy to implement, which greatly reduces the difficulty and cost of preparing the mercury isotope diluent.

[0062] Second, it solves the problem of the difficulty and high cost of purchasing single mercury isotopes. Mercury isotope diluents can be obtained very simply and quickly, greatly facilitating research in the field of environmental mercury and significantly reducing technology and research costs.

[0063] Third, compared with using a single mercury isotope as a diluent, the present invention can change the addition method according to experimental conditions, and can be added in liquid or gaseous form, and the amount added can be quickly adjusted by a peristaltic pump. During the application process of a single mercury isotope, multiple stages of dilution and redox are required, which can easily cause the loss of mercury isotope samples, making the amount added to the environmental sample inaccurate;

[0064] Fourth, the mercury isotope diluent prepared by the present invention can be stored for a long time after being adsorbed by the mercury enrichment tube, and the enriched mercury will basically not be lost. It is also very convenient to carry to the field for experiments and research. The diluent of a single mercury isotope needs to be prepared into a liquid mercury standard solution, which is very inconvenient to carry to the field. In addition, the mercury standard solution will lose a lot of mercury if it is left for a long time.

[0065] Fifth, the device of the present invention can also be used directly on site. The gaseous mercury reduced by the gas-liquid separator 24 is directly introduced into the gas environment sample to be added, saving the costs of enrichment, storage and transportation of mercury isotope diluents.

[0066] Sixth, the mercury isotope diluent prepared by the present invention is taken from natural biological samples, and has relatively little pollution and impact on the environment after being added to the environment. However, directly adding a single mercury isotope diluent will cause more serious pollution to the environmental samples around the experiment, making it impossible to carry out research on mercury isotopes in natural environmental samples at the experimental site for a long time.

[0067] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles described in the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A device for preparing a mercury isotope diluent, characterized in that: It includes a digestion unit, a reduction unit and an enrichment unit connected in sequence; The digestion unit comprises a digestion reactor (11), an oxidant storage container (12), and an oxidant extraction device (13). The oxidant extraction device (13) can extract the solution or gas in the oxidant storage container (12) into the digestion reactor (11). The digestion reactor (11) is provided with a stirrer (111); The reduction unit comprises a reducing agent storage container (21), a digestion liquid extraction device (22), a reducing agent extraction device (23) and a gas-liquid separator (24); the digestion liquid extraction device (22) can extract the solution or gas in the digestion reactor (11) into the gas-liquid separator (24); and the reducing agent extraction device (23) can extract the solution or gas in the reducing agent storage container (21) into the gas-liquid separator (24); The oxidant storage container (12) stores a strong oxidant; The reducing agent storage container (21) stores a reducing agent; The digestion reactor (11), the digestion liquid extraction device (22) and the components in the enrichment unit are all made of Teflon or borosilicate glass.

2. The device for preparing a mercury isotope diluent according to claim 1, characterized in that: The oxidant extraction device (13), the digestion liquid extraction device (22), and the reducing agent extraction device (23) are all pipes equipped with peristaltic pumps.

3. The device for preparing a mercury isotope diluent according to claim 1, characterized in that: The gas-liquid separator (24) comprises a gas-liquid separation tube (241) and a waste liquid bottle (242), and the waste liquid bottle (242) is connected to the liquid end of the gas-liquid separation tube (241).

4. The device for preparing a mercury isotope diluent according to claim 3, characterized in that: The enrichment unit comprises a drying tube (31) and a mercury enrichment tube (32), one end of the drying tube (31) is connected to the gas end of the gas-liquid separation tube (241), and the other end of the drying tube (31) is connected to the mercury enrichment tube (32), and a mercury adsorbent is provided in the mercury enrichment tube (32).

5. The device for preparing a mercury isotope diluent according to claim 4, characterized in that: The drying tube (31) is provided with a soda lime desiccant.

6. The device for preparing a mercury isotope diluent according to claim 4, characterized in that: Mercury adsorbents are modified activated carbon with a particle size of less than 1 mm, quartz sand gold-plated particles or pure gold particles.

7. The device for preparing a mercury isotope diluent according to claim 4, characterized in that: The enrichment unit further comprises a three-way valve (33) and an environmental sample pipe (34), wherein the three-way valve (33) is connected to the drying pipe (31), the gas-liquid separator (24) and the environmental sample pipe (34).

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