A collection device and analysis method for measuring sulfur isotopes of sulfur dioxide in the atmosphere

Abstract

This invention belongs to the field of isotope measurement technology, specifically relating to a collection device and analysis method for measuring sulfur isotopes in atmospheric sulfur dioxide. The collection device comprises a sequentially connected gas inlet bottle, a first drying tube, a filter, a sulfuric acid vapor collector, a sulfur dioxide collector, an ice bath, a second drying tube, a flowmeter, and a vacuum pump. The collection device utilizes an integrated design, integrating condensation, oxidation, and precipitation functions. This simplifies sample pretreatment, avoids cross-contamination, and improves analysis accuracy and efficiency. Furthermore, when used in conjunction with a nanometer secondary ion mass spectrometer (NanoSIMS) for sulfur isotope analysis, the collection device significantly reduces sample volume requirements and shortens sampling time to hours, enabling short-term monitoring.

Description

Technical Field

[0001] The present invention belongs to the technical field of isotope measurement, and in particular relates to a collection device and an analysis method for measuring sulfur isotopes of sulfur dioxide in the atmosphere. Background Art

[0002] SO₂ is rapidly oxidized in the atmosphere, forming sulfate aerosols through homogeneous oxidation in the gas phase or heterogeneous oxidation in the liquid phase. Sulfate aerosols are a significant component of fine particulate matter in urban atmospheres and a major source of acid deposition. Therefore, determining the sources of atmospheric SO₂ in different regions and its atmospheric transformation processes is crucial for quantitatively assessing the physical and chemical effects of regional environmental sulfate aerosols and understanding the impacts of atmospheric SO₂ and sulfate aerosols on the global environment. Due to the "fingerprint" characteristics of stable sulfur isotope composition, sulfur isotope tracing technology has been widely applied in environmental research on sulfur cycling and sulfur source apportionment. Analyzing the sulfur isotope composition of SO₂ and sulfate aerosols can effectively indicate the sources of SO₂ and the transformation pathways from SO₂ oxidation to sulfate.

[0003] Currently, the alkali tablet method is the primary method for collecting SO2 gas samples for SO2 sulfur isotope determination. The sampling process can be divided into passive and active sampling, depending on the sampling method. Passive sampling involves placing the filter membrane with the hair side facing outward in a plastic sampling dish, pressing the edges with a plastic gasket, and securing the filter membrane face down in the sampling rack. The sampling period is typically 30 ± 2 days. Active sampling is typically performed using a suspended particulate sampler. During sampling, a clean, unsoaked glass fiber filter is placed in the upper layer of a double-layer sampler, while a soaked glass fiber filter is placed in the lower layer. The upper layer collects aerosols, while the lower layer collects atmospheric SO2. The sampling flow rate is typically 100–1000 L / min, and the sampling duration ranges from one day to several days. After the sample is collected, the filter membrane needs to be cut into pieces and placed in ultrapure water for extraction and filtration. Then H2O2 is added to oxidize the sulfite into sulfate. Subsequently, BaCl2 solution is added to produce BaSO4 precipitate. The pure BaSO4 precipitate is filtered and dried to obtain the pure BaSO4 precipitate. The obtained BaSO4 precipitate needs to be further purified and undergoes processes such as weighing, loading, and vacuuming. The BaSO4 is then converted into sulfur dioxide (SO2) at 980°C using the vanadium pentoxide (V2O5) method. The SO2 is purified and collected, and the SO2 is introduced into a gas isotope mass spectrometer for sulfur isotope composition analysis.

[0004] However, the prior art has the following disadvantages:

[0005] (1) Low sampling efficiency: Passive sampling relies on the natural diffusion of gas to the filter membrane. In a low-concentration environment, it takes a long time to accumulate enough SO2. The sampling cycle is long and it cannot reflect the sudden pollution dynamics of several hours to several days in real time.

[0006] (2) High sample volume requirement: Traditional gas isotope mass spectrometers (such as IRMS) have limited sensitivity and require sufficient BaSO4 precipitation (not less than 1 mg) to ensure the signal-to-noise ratio. This results in the need to extend the sampling time or increase the flow rate in low-concentration environments, which cannot meet the needs of rapid trace sulfur analysis.

[0007] (3) Sample pre-treatment is complex: during the sample collection and preparation process, the filter membrane needs to be soaked (K2CO3 + The steps of extraction, extraction with water, oxidation with H2O2, precipitation with BaCl2, filtration and drying are cumbersome and can easily lead to sample loss or contamination. At the same time, gaseous sulfuric acid in the atmosphere may also be collected on the filter membrane, causing interference with the analysis of sulfur isotopes in SO2.

[0008] (4) Risk of sulfur isotope fractionation: During the process of absorbing atmospheric SO2 by the filter membrane (treated with K2CO3), the contact time between the filter membrane and the collected gas is short. If the SO2 gas cannot be 100% absorbed, the sulfur isotopes may be separated due to mass differences (such as 32 S and 34 S) results in different adsorption efficiencies, thus causing fractionation during the sampling process. Summary of the Invention

[0009] In response to the above-mentioned deficiencies in the prior art, the present invention provides a collection device and analysis method for measuring sulfur isotopes in sulfur dioxide in the atmosphere, which solves the problems of low sampling efficiency, complex pre-processing and sulfur isotope fractionation in the prior art.

[0010] To achieve the above object, the technical solution adopted by the present invention is:

[0011] Provided are a collection device and analysis method for measuring sulfur isotopes of sulfur dioxide in the atmosphere, comprising an air inlet bottle, a first drying tube, a filter, a sulfuric acid vapor collector, a sulfur dioxide collector, an ice bath device, a second drying tube, a flow meter, and a vacuum pump, which are connected in sequence;

[0012] The sulfuric acid vapor collector includes a first inner tube and a first outer tube arranged outside the first inner tube, a condensed water inlet is provided on one side of the upper end of the first outer tube, a condensed water outlet is provided on one side of the lower end of the first outer tube, a first air outlet is provided on the other side of the upper ends of the first inner tube and the first outer tube, a first air inlet is provided on the other side of the lower ends of the first inner tube and the first outer tube, and a barb is provided inside the first inner tube.

[0013] The beneficial effects of adopting the above technical solution are as follows: the vacuum pump in the collection device is used to provide a negative pressure environment, so that air can enter the device smoothly and be subsequently collected and processed; the flow meter is used to measure and control the air flow velocity entering the collection device, and the sampling time and sampling volume can be controlled by the flow meter at the same time; the air inlet bottle is used to input the air to be measured, and the air is input through the air inlet bottle and then passes through the first drying tube, which can be used to remove moisture in the air to avoid the interference of moisture in the air on the subsequent sulfur isotope analysis; the air dried by the first drying tube enters the filter, which is used to remove particulate matter in the air to avoid the influence of particulate matter on the collection of subsequent sulfur dioxide samples; the air filtered by the filter enters the sulfuric acid vapor collector, which is equipped with a A receiving chamber for condensed water is formed between the first inner tube and the first outer tube. The condensed water enters the receiving chamber from the condensed water inlet, and is used to reduce the temperature of the sulfuric acid vapor collector, so that the sulfuric acid vapor in the air is condensed into droplets, thereby avoiding interference with the subsequent sulfur isotope measurement of SO2. In addition, the condensed water inlet and the condensed water outlet can realize the recycling of condensed water, thereby improving the condensation efficiency and ensuring the collection efficiency of sulfuric acid vapor. The barbs arranged inside the first inner tube can effectively increase the flow path and contact area of the air, while disrupting the gas flow, making it easier for sulfuric acid vapor to condense on the tube wall. Subsequently, the air enters the sulfur dioxide collector, which is used to capture and oxidize sulfur dioxide in the air and oxidize the sulfur dioxide into sulfate ions (SO4 2- ), to achieve rapid conversion, then the air enters the ice bath device to remove water vapor in the air, and the ice bath device condenses the water vapor in the air into liquid water and removes it by lowering the temperature to prevent interference from water vapor. The air after the ice bath device enters the second drying tube, which can remove moisture in the air for a second time to prevent damage to the flow meter.

[0014] The collection device adopts an integrated design and integrates condensation, oxidation and precipitation functions, which simplifies the sample pretreatment process, avoids cross-contamination, and improves the accuracy and efficiency of analysis. At the same time, when used with a nano secondary ion mass spectrometer (NanoSIMS) for sulfur isotope analysis, the collection device significantly reduces the sample volume requirement and shortens the sampling time to hours, realizing short-term monitoring.

[0015] Furthermore, a first sealing cover is provided at the top of the sulfur dioxide collector, a first air inlet pipe and a first air outlet pipe are provided on the first sealing cover, and an oxidant is provided inside the sulfur dioxide collector.

[0016] The beneficial effects of the above technical solution are as follows: the first sealing cover ensures the sealing of the sulfur dioxide collector, prevents the entry of external air or impurities, thereby ensuring the purity of the collected sulfur dioxide and the accuracy of the analysis; the first air inlet pipe allows external air to enter the sulfur dioxide collector, and the first air outlet pipe is used to discharge the treated gas; and the oxidant provided in the sulfur dioxide collector is used to completely oxidize the sulfur dioxide in the air into sulfate ions (SO4 2- ), which realizes the rapid conversion of sulfur dioxide, not only effectively improving the collection efficiency of sulfur dioxide, but also avoiding the fractionation of sulfur isotopes during the sampling process, and simplifying the subsequent processing steps, greatly improving the collection and analysis efficiency.

[0017] Furthermore, the ice bath device includes an ice bath tank, an ice bath bottle is arranged in the ice bath tank, glass wool is arranged in the ice bath bottle, a second sealing cover is arranged on the top of the ice bath bottle, and a second air inlet pipe and a second air outlet pipe are arranged on the upper end of the second sealing cover.

[0018] The beneficial effects of adopting the above technical solution are as follows: the ice bath tank is used to place ice cubes or refrigerant to lower the temperature of the ice bath bottle, which is conducive to condensing residual water vapor in the air. The second sealing cover on the top of the ice bath bottle ensures the sealing and prevents impurities in the external air from entering, thereby ensuring the purity of the input air and the accuracy of the analysis. The glass wool arranged inside the ice bath bottle can effectively reduce the heat exchange between the inside of the ice bath bottle and the outside world, maintain the stability of the low-temperature environment, and thus improve the condensation efficiency of water vapor.

[0019] Furthermore, a second air inlet is provided at one end of the air inlet bottle, and the second air inlet is trumpet-shaped, and a second air outlet is provided at the other end of the air inlet bottle.

[0020] The beneficial effects of adopting the above technical solution are: the trumpet-shaped second air inlet can guide the airflow into the air inlet bottle, while increasing the contact area between the second air inlet and the airflow, thereby improving the collection amount of sampled gas.

[0021] Furthermore, the first drying tube and the second drying tube both include a second inner tube and a second outer tube arranged outside the second inner tube. A third air inlet pipe is arranged in the middle of the second inner tube. A plurality of through holes are arranged on the third air inlet pipe. The third air inlet pipe passes through the second outer tube. A desiccant is arranged between the second inner tube and the second outer tube.

[0022] The beneficial effects of adopting the above technical solution are as follows: the first drying tube and the second drying tube adopt a double-layer structure, a accommodating chamber for accommodating the desiccant is formed between the second inner tube and the second outer tube, the third air inlet pipe ensures the smooth input of air, and the several through holes provided on the third air inlet pipe enable the gas to fully contact with the desiccant when flowing through the drying tube, thereby ensuring the removal of moisture in the air.

[0023] Furthermore, the gas inlet bottle, the first drying tube, the filter, the sulfuric acid vapor collector, the sulfur dioxide collector, the ice bath device, the second drying tube, the flow meter and the vacuum pump are connected through a conductive silicone tube.

[0024] The beneficial effects of adopting the above technical solution are: the conductive silicone tube has excellent elasticity and flexibility, which can not only ensure the close connection between the components and prevent gas leakage, but also withstand certain pressure and temperature changes, ensuring the stability and reliability of the sampling and analysis process.

[0025] Based on the above-mentioned collection device for measuring sulfur isotopes of sulfur dioxide in the atmosphere, an analysis method for measuring sulfur isotopes of sulfur dioxide in the atmosphere is provided, which specifically includes the following steps:

[0026] S1: Collecting sulfur dioxide gas: Turn on the vacuum pump, set the flow rate of the flow meter, and input outdoor air through the second air inlet. The input air passes through the air inlet bottle, the first drying tube, the filter, the sulfuric acid vapor collector, the sulfur dioxide collector, the ice bath device and the second drying tube in sequence. Run for 4 to 16 hours, and then turn off the vacuum pump;

[0027] S2: Prepare BaSO4 precipitate: Pour the solution in the sulfur dioxide collector into a beaker, add an acidic solvent to adjust the pH, then add BaCl2 solution while stirring continuously. After adding the BaCl2 solution, let it stand until BaSO4 precipitate is precipitated;

[0028] S3: Preparation of BaSO4 particles: Adjust the pH of the solution after standing with ultrapure water. After adjustment, filter it with a gold-plated filter membrane and wash the BaSO4 precipitate with ultrapure water. After filtration, obtain BaSO4 particles. Place the filter membrane with BaSO4 particles in a drying oven for drying.

[0029] S5: Analysis of BaSO4 particles: Use nano-secondary ion mass spectrometry to analyze the dried BaSO4 particles, and analyze the BaSO4 standard sample and the precipitated BaSO4 particles to determine the sulfur isotope content.

[0030] The beneficial effects of adopting the above technical solution are as follows: in S1, by turning on the vacuum pump and setting the flow rate of the flow meter, the gas flow rate and sampling time during the sampling process can be accurately controlled to ensure that the collected sulfur dioxide sample is representative. At the same time, the gas can be effectively removed from the gas through the gas inlet bottle, drying tube, and filter. Impurities such as moisture and particulate matter in the gas can be effectively removed, thereby improving the accuracy of subsequent analysis; in S2, sulfur dioxide is converted into a stable BaSO4 precipitate through a chemical reaction, which is convenient for subsequent analysis and measurement. The BaSO4 precipitate is then completely precipitated by standing, thereby improving the purity and quality of the precipitate. ; In S3, pure BaSO4 precipitate can be obtained by filtration and washing, and the gold-plated filter membrane refers to the pre-gold plating of the non-conductive polycarbonate filter membrane to make it conductive, which is convenient for the subsequent sulfur isotope analysis using a nano-secondary ion mass spectrometer; in S4, the dried BaSO4 particles are analyzed using a nano-secondary ion mass spectrometer. By comparing the sulfur isotope content of the BaSO4 standard sample and the precipitated BaSO4 particles, the sulfur isotope composition of sulfur dioxide in the atmosphere can be accurately determined. This process realizes high-precision measurement of sulfur isotopes in sulfur dioxide.

[0031] Furthermore, the flow rate of the flow meter is 0.5 to 2 L / min.

[0032] The beneficial effect of adopting the above technical solution is that when the flow rate of the flow meter is set within the range of 0.5 to 2 L / min, the flow meter can improve the collection effect of sulfur dioxide and reduce equipment damage and maintenance costs caused by excessive or insufficient flow.

[0033] Furthermore, in S2, pH < 3, and the molar concentration of the BaCl2 solution is 2 mol / L.

[0034] The beneficial effects of the above technical solution are: when pH < 3, sulfate ions (SO4 2- ) and barium ions (Ba 2+ ) reacts more rapidly and completely, which is not only conducive to the formation of BaSO4 precipitation, but also inhibits the reaction of other metal ions or impurities, thereby improving the yield and purity of BaSO4 precipitation, and providing high-quality samples for subsequent isotope analysis; at the same time, in the process of preparing BaSO4 precipitation, BaCl2 solution reacts with sulfate ions (SO4 2- ) reaction to form an insoluble BaSO4 precipitate; a BaCl2 solution with a molar concentration of 2 mol / L can ensure that there are enough barium ions (Ba 2+ ) combines with sulfate ions to efficiently generate BaSO4 precipitate.

[0035] Furthermore, in S3, the thickness of the gold-plated layer of the gold-plated filter membrane is less than 10 nm.

[0036] The beneficial effects of adopting the above technical solution are: the gold plating layer can increase the conductivity of the polycarbonate filter membrane, and the gold plating layer with a thickness of less than 10nm can not only ensure the filtration performance of the filter membrane, but also ensure that the sample will not be lost or contaminated during the filtration process.

[0037] In summary, the collection device and analysis method for measuring sulfur isotopes of sulfur dioxide in the atmosphere provided by the present invention have the following beneficial effects:

[0038] (1) The collection device adopts an integrated design, which reduces the number of operation steps and equipment, reduces the complexity and cost of operation, and integrates the gas inlet bottle, the first drying tube, the filter, the sulfuric acid vapor collector, the sulfur dioxide collector, the ice bath device, the second drying tube, the flow meter and the vacuum pump, thereby realizing the efficient collection and pretreatment of sulfur dioxide and sulfate in the atmosphere, reducing the loss of samples during the collection and transfer process, and avoiding cross contamination, thereby improving the accuracy and efficiency of the analysis.

[0039] (2) The sulfuric acid vapor collector in the collection device increases the path length and contact area of the gas flow through the barbed structure, which can effectively collect sulfuric acid vapor in the air and prevent it from interfering with the subsequent sulfur isotope measurement of sulfur dioxide.

[0040] (3) This analytical method uses nanosecondary ion mass spectrometry (NanoSIMS) to perform sulfur isotope analysis on single-particle BaSO4. The required sample amount is as low as microgram level, which significantly reduces the sample amount required for instrument analysis.

[0041] (4) This analytical method uses a nuclear pore polycarbonate filter membrane with a gold-plated layer thickness of <10 nm for one-step filtration, eliminating the need for complex extraction and purification steps, thus simplifying the pre-treatment process.

[0042] (5) This analytical method can completely oxidize sulfur dioxide to sulfate ions (SO4 2- ), avoiding the sulfur isotope fractionation caused by incomplete adsorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the structure of the collection device in the present invention;

[0044] Figure 2 is a flow chart of sulfur isotope analysis in the present invention;

[0045] Figure 3 is a scanning electron microscope image of a sample in an embodiment of the present invention;

[0046] Figure 4 (a) is the sample obtained by NanoSIMS analysis in the embodiment of the present invention. 32 S and (b) 34 S content and distribution diagram;

[0047] Among them, 1. Air inlet bottle; 2. First drying tube; 3. Filter; 4. Sulfuric acid vapor collector; 41. First inner tube; 42. First outer tube; 43. Condensate inlet; 44. Condensate outlet; 45. First air inlet; 46. First air outlet; 5. Sulfur dioxide collector; 51. First sealing cover; 52. First air inlet pipe; 53. First air outlet; 6. Ice bath device; 61. Ice bath tank; 62. Ice bath bottle; 63. Glass wool; 64. Second sealing cover; 65. Second air inlet pipe; 66. Second air outlet; 7. Second drying tube; 71. Third air inlet pipe. DETAILED DESCRIPTION

[0048] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0049] Example 1

[0050] like Figure 1 As shown, the collection device and analysis method for measuring sulfur isotopes of sulfur dioxide in the atmosphere provided by the present invention include an air inlet bottle 1, a first drying tube 2, a filter 3, a sulfuric acid vapor collector 4, a sulfur dioxide collector 5, an ice bath device 6, a second drying tube 7, a flow meter and a vacuum pump connected in sequence. Among them, the vacuum pump is used to provide a negative pressure environment so that the air can enter the device smoothly and be subsequently collected and processed. The flow meter is used to measure and control the air flow velocity entering the collection device. At the same time, the sampling time and sampling volume can be controlled by the flow meter. The air inlet bottle 1 is used to input the air to be tested. After the air is input through the air inlet bottle 1, it passes through the first drying tube 2. The first drying tube 2 can be used to remove moisture in the air to avoid the interference of moisture in the air on the subsequent sulfur isotope analysis. The air dried by the first drying tube 2 enters the filter 3. The filter 3 is used to remove particulate matter in the air to avoid the influence of particulate matter on the collection of subsequent sulfur dioxide samples. The air filtered by the filter 3 enters the sulfuric acid vapor collector 4, which can be used to collect sulfuric acid vapor in the air to avoid interference with the subsequent sulfur isotope measurement of sulfur dioxide. Subsequently, the air enters the sulfur dioxide collector 5. The sulfur dioxide collector 5 is used to capture and oxidize sulfur dioxide in the air to oxidize sulfur dioxide into sulfate ions (SO4 2-), achieving rapid conversion, and then the air enters the ice bath device 6 for removing water vapor in the air. The ice bath device 6 condenses the water vapor in the air into liquid water and removes it by lowering the temperature to prevent interference from water vapor. The air after passing through the ice bath device 6 enters the second drying tube 7, which can remove moisture in the air for a second time to prevent damage to the flow meter.

[0051] like Figure 1 As shown, a second air inlet is provided at one end of the air inlet bottle 1, and the second air inlet is in a trumpet shape. A second air outlet is provided at the other end of the air inlet bottle 1. The trumpet-shaped second air inlet can guide the airflow into the air inlet bottle 1, while increasing the contact area between the second air inlet and the airflow, thereby increasing the amount of sampled gas collected.

[0052] like Figure 1 As shown, the first drying tube 2 and the second drying tube 7 both include a second inner tube and a second outer tube arranged outside the second inner tube. A third air inlet pipe 71 is provided in the middle of the second inner tube. The third air inlet pipe 71 is provided with a plurality of through holes. The third air inlet pipe 71 passes through the second outer tube. A desiccant is provided between the second inner tube and the second outer tube. The first drying tube 2 and the second drying tube 7 adopt a double-layer structure. A accommodating cavity for accommodating a desiccant such as silica gel is formed between the second inner tube and the second outer tube. The third air inlet pipe 71 ensures the smooth input of air. The plurality of through holes provided on the third air inlet pipe 71 allow the gas to fully contact with the desiccant when flowing through the drying tube, thereby ensuring the removal of moisture in the air.

[0053] like Figure 1 As shown, the sulfuric acid vapor collector 4 includes a first inner tube 41 and a first outer tube 42 arranged outside the first inner tube 41, a condensate inlet 43 is provided on one side of the upper end of the first outer tube 42, a condensate outlet 44 is provided on one side of the lower end of the first outer tube 42, a first air outlet 46 is provided on the other side of the upper ends of the first inner tube 41 and the first outer tube 42, a first air inlet 45 is provided on the other side of the lower ends of the first inner tube 41 and the first outer tube 42, and a barb is provided inside the first inner tube 41. The sulfuric acid vapor collector 4 is supported by quartz glass, and a receiving chamber for condensed water to pass through is formed between the first inner tube 41 and the first outer tube 42. The condensed water enters the receiving chamber from the condensed water inlet 43, which is used to reduce the temperature of the sulfuric acid vapor collector 4, so that the sulfuric acid vapor in the air is condensed into droplets, avoiding interference with the subsequent sulfur isotope measurement of SO2. In addition, the condensed water inlet 43 and the condensed water outlet 44 can realize the recycling of condensed water, thereby improving the condensation efficiency and ensuring the collection efficiency of sulfuric acid vapor; and the barbs arranged inside the first inner tube 41 can effectively increase the flow path and contact area of the air, while disrupting the gas flow, making it easier for sulfuric acid vapor to condense on the tube wall.

[0054] like Figure 1As shown, a first sealing cover 51 is provided at the top of the sulfur dioxide collector 5. A first air inlet pipe 52 and a first air outlet pipe 53 are provided on the first sealing cover 51. An oxidant is provided inside the sulfur dioxide collector 5. The sulfur dioxide collector 5 is made of materials such as polytetrafluoroethylene and cannot be made of metal materials to prevent metal dissolution from affecting the sulfur isotope analysis structure. The first sealing cover 51 ensures the sealing of the sulfur dioxide collector 5 and prevents the entry of external air or impurities, thereby ensuring the purity of the collected sulfur dioxide and the accuracy of the analysis. The first air inlet pipe 52 allows external air to enter the sulfur dioxide collector 5, while the first air outlet pipe 53 is used to discharge the treated gas. The oxidant provided inside the sulfur dioxide collector 5 is 100 ml of a 10% hydrogen peroxide (H2O2) solution. The H2O2 solution ensures that the sulfur dioxide is 100% oxidized to SO4 2- , eliminating the mass difference fractionation caused by incomplete adsorption, not only effectively improves the collection efficiency of sulfur dioxide, but also avoids the fractionation of sulfur isotopes during the sampling process, simplifies the subsequent processing steps, and greatly improves the collection and analysis efficiency.

[0055] like Figure 1 As shown, the ice bath device 6 includes an ice bath tank 61, an ice bath bottle 62 disposed within the ice bath tank 61, glass wool 63 disposed within the ice bath bottle 62, a second sealing cap 64 disposed at the top of the ice bath bottle 62, and a second air inlet pipe 65 and a second air outlet pipe 66 disposed at the upper end of the second sealing cap 64. The ice bath tank 61 is used to hold ice cubes or refrigerant, thereby lowering the temperature of the ice bath bottle 62 and facilitating the condensation of residual water vapor in the air. The second sealing cap 64 at the top of the ice bath bottle 62 ensures a tight seal, preventing impurities from the outside air from entering, thereby ensuring the purity of the input air and the accuracy of the analysis. The glass wool 63 disposed within the ice bath bottle 62 can effectively reduce heat exchange between the interior of the ice bath bottle 62 and the outside world, maintaining a stable low-temperature environment, and thereby improving the condensation efficiency of water vapor.

[0056] This collection device features an integrated design, integrating condensation, oxidation, and precipitation functions. It uses a gold-plated filter membrane for single-step filtration, and oxidation and precipitation are performed directly after sampling. The filter membrane is then ready for NanoSIMS analysis, eliminating the need for membrane shredding, multiple extractions, and high-temperature conversion. Traditional methods require more than seven pretreatment steps (such as soaking, extraction, oxidation, precipitation, filtration, drying, and conversion to sulfur dioxide). This simplifies the sample pretreatment process, avoids cross-contamination, and improves analytical accuracy and efficiency. Furthermore, when used in conjunction with a nanometer secondary ion mass spectrometer (NanoSIMS) for sulfur isotope analysis, this significantly reduces sample volume requirements and shortens sampling time to hours, enabling short-term monitoring.

[0057] Example 2

[0058] Based on the above-mentioned acquisition device for measuring sulfur isotopes of sulfur dioxide in the atmosphere, such as Figure 2 As shown, an analytical method for measuring sulfur isotopes of sulfur dioxide in the atmosphere is provided, which specifically includes the following steps:

[0059] S1: Collecting sulfur dioxide gas: Turn on the vacuum pump, set the flow rate of the flow meter, and input outdoor air through the second air inlet. The input air passes through the air inlet bottle 1, the first drying tube 2, the filter 3, the sulfuric acid vapor collector 4, the sulfur dioxide collector 5, the ice bath device 6 and the second drying tube 7 in sequence. Run for 4 to 16 hours, and then turn off the vacuum pump;

[0060] S2: Prepare BaSO4 precipitate: Pour the solution in the sulfur dioxide collector 5 into a beaker, add an acidic solvent to adjust the pH, then add BaCl2 solution while stirring continuously. After adding the BaCl2 solution, let it stand until BaSO4 precipitate is precipitated;

[0061] S3: Preparation of BaSO4 particles: Adjust the pH of the solution after standing with ultrapure water. After adjustment, filter it with a gold-plated filter membrane and wash the BaSO4 precipitate with ultrapure water. After filtration, obtain BaSO4 particles. Place the filter membrane with BaSO4 particles in a drying oven for drying.

[0062] S5: Analysis of BaSO4 particles: Use nano-secondary ion mass spectrometry to analyze the dried BaSO4 particles, and analyze the BaSO4 standard sample and the precipitated BaSO4 particles to determine the sulfur isotope content.

[0063] In S1, the vacuum pump and flow meter are turned on to start the sampling device, and the running time is 4 to 16 hours. By turning on the vacuum pump and setting the flow rate of the flow meter, the gas flow rate and sampling time during the sampling process can be accurately controlled to ensure that the collected sulfur dioxide sample is representative. At the same time, impurities such as moisture and particulate matter in the gas can be effectively removed through the gas inlet bottle 1, drying tube, and filter 3, thereby improving the accuracy of subsequent analysis.

[0064] The acidic solvent added to S2 can be HCl solution, and the pH is less than 3, and the molar concentration of BaCl2 solution is 2 mol / L. When pH is less than 3, sulfate ions (SO4 2- ) and barium ions (Ba 2+ ) reacts more rapidly and completely, which is not only conducive to the formation of BaSO4 precipitation, but also inhibits the reaction of other metal ions or impurities, thereby improving the yield and purity of BaSO4 precipitation, and providing high-quality samples for subsequent isotope analysis; at the same time, in the process of preparing BaSO4 precipitation, BaCl2 solution reacts with sulfate ions (SO4 2-) reaction to form an insoluble BaSO4 precipitate; a BaCl2 solution with a molar concentration of 2 mol / L can ensure that there are enough barium ions (Ba 2+ ) combines with sulfate ions to efficiently generate BaSO4 precipitate.

[0065] In S3, the pH of the solution after standing is adjusted to >5 with ultrapure water to reduce the solution's acidity and prevent damage to the filter membrane during subsequent filtration. The gold-plated membrane has a thickness of <10 nm. The membrane has a diameter of 25 mm and a pore size of 0.2 μm. The gold coating enhances the conductivity of the polycarbonate membrane. A thickness of <10 nm not only ensures the membrane's filtration performance but also prevents isotope fractionation caused by incomplete airflow contact or residual reagents (such as K₂CO₃) in traditional filter membranes. This also ensures that no sample is lost or contaminated during the filtration process. The filter membrane with BaSO₄ particles is then dried at 50°C for 1 hour and stored for subsequent sulfur isotope analysis using a nano-secondary ion mass spectrometer.

[0066] In S4, a nano-secondary ion mass spectrometer is used to analyze the dried BaSO4 particles. By comparing the sulfur isotope content of the BaSO4 standard sample and the precipitated BaSO4 particles, the sulfur isotope composition of sulfur dioxide in the atmosphere can be accurately determined. This process achieves high-precision measurement of sulfur isotopes in sulfur dioxide.

[0067] This analytical method uses nanosecondary ion mass spectrometry (NanoSIMS) to perform sulfur isotope analysis on single-particle BaSO4. The required sample amount is as low as microgram level, significantly reducing the sample amount required for instrument analysis.

[0068] Example 3

[0069] Based on the collection device in Example 1 and the analysis method in Example 2, a sample collection and analysis experiment was conducted when the SO2 concentration in the atmospheric environment was 4 ppb. The sampling time was 6 hours. After precipitation and filtration according to the above method, the gold-plated polycarbonate filter membrane with BaSO4 precipitation was first subjected to scanning electron microscopy (SEM). The SEM image is shown in FIG. Figure 3 As shown, after confirming that BaSO4 particles were obtained, the sulfur isotope situation was further analyzed by NanoSIMS. The analysis results are shown in Figure 4 As shown, the sulfur isotopes of 12 BaSO4 particles analyzed by NanoSIMS 32 S and 34 The instrument detection signal values of S and their ratios are shown in Table 1.

[0070] Table 1 Analysis of 12 BaSO4 particles 34 S / 32 S ratio

[0071]

[0072] like Figure 3 、 Figure 4 As can be seen from Table 1, the acquisition device and analysis method for measuring sulfur isotopes of sulfur dioxide in the atmosphere provided by the present invention have high accuracy and reliability, and can be used for the source analysis of atmospheric SO2 in different regions and the study of its transformation process in the atmosphere. It is of great significance for the quantitative evaluation of the physical and chemical effects of regional environmental sulfate aerosols. It can also be used to monitor the pollution status of sulfur dioxide in the atmosphere, providing a scientific basis for environmental protection and pollution control.

[0073] In summary, the collection device and analysis method for measuring sulfur isotopes of sulfur dioxide in the atmosphere provided by the present invention simplifies the pretreatment process and reduces operational errors. It can not only significantly reduce the demand for instrument analysis samples and realize short-term pollution monitoring, but also avoid sulfur isotope fractionation and effectively remove interfering substances, thereby ensuring the accuracy of the data.

Claims

1. A collection device for measuring sulfur isotopes of sulfur dioxide in the atmosphere, characterized by: It comprises an air inlet bottle (1), a first drying tube (2), a filter (3), a sulfuric acid vapor collector (4), a sulfur dioxide collector (5), an ice bath device (6), a second drying tube (7), a flow meter and a vacuum pump, which are connected in sequence; The sulfuric acid vapor collector (4) comprises a first inner tube (41) and a first outer tube (42) arranged outside the first inner tube (41); a condensed water inlet (43) is provided on one side of the upper end of the first outer tube (42); a condensed water outlet (44) is provided on one side of the lower end of the first outer tube (42); a first air outlet (46) is provided on the other side of the upper ends of the first inner tube (41) and the first outer tube (42); a first air inlet (45) is provided on the other side of the lower ends of the first inner tube (41) and the first outer tube (42); and a barb is provided inside the first inner tube (41) for enhancing turbulence at low flow rates to improve the condensation efficiency of sulfuric acid vapor. A first sealing cover (51) is provided at the top of the sulfur dioxide collector (5), and a first air inlet pipe (52) and a first air outlet pipe (53) are provided on the first sealing cover (51). An oxidant is provided inside the sulfur dioxide collector (5), and the oxidant is a 10% concentration hydrogen peroxide solution, which is used to directly oxidize sulfur dioxide into sulfate ions to avoid sulfur isotope fractionation; The ice bath device (6) comprises an ice bath tank (61), an ice bath bottle (62) is arranged in the ice bath tank (61), glass wool (63) is arranged in the ice bath bottle (62), a second sealing cover (64) is arranged at the top end of the ice bath bottle (62), and a second air inlet pipe (65) and a second air outlet pipe (66) are arranged at the upper end of the second sealing cover (64).

2. The device for collecting sulfur isotopes of sulfur dioxide in the atmosphere according to claim 1, characterized in that: One end of the gas inlet bottle (1) is provided with a second gas inlet, the second gas inlet is trumpet-shaped, and the other end of the gas inlet bottle (1) is provided with a second gas outlet.

3. The device for collecting sulfur isotopes of sulfur dioxide in the atmosphere according to claim 1, characterized in that: The first drying tube (2) and the second drying tube (7) both comprise a second inner tube and a second outer tube arranged outside the second inner tube; a third air inlet tube (71) is arranged in the middle of the second inner tube; a plurality of through holes are provided on the third air inlet tube (71); the third air inlet tube (71) passes through the second outer tube; and a desiccant is provided between the second inner tube and the second outer tube.

4. The device for collecting sulfur isotopes of sulfur dioxide in the atmosphere according to claim 1, characterized in that: The gas inlet bottle (1), the first drying tube (2), the filter (3), the sulfuric acid vapor collector (4), the sulfur dioxide collector (5), the ice bath device (6), the second drying tube (7), the flow meter and the vacuum pump are connected via a conductive silicone tube.

5. An analytical method for measuring sulfur isotopes of sulfur dioxide in the atmosphere, based on the acquisition device for measuring sulfur isotopes of sulfur dioxide in the atmosphere according to any one of claims 1 to 4, characterized in that: The specific steps include: S1: Collecting sulfur dioxide gas: Turn on the vacuum pump, set the flow rate of the flow meter, input outdoor air through the second air inlet, and the input air passes through the air inlet bottle (1), the first drying tube (2), the filter (3), the sulfuric acid vapor collector (4), the sulfur dioxide collector (5), the ice bath device (6) and the second drying tube (7) in sequence. Run for 4 to 16 hours, and then turn off the vacuum pump; S2: Preparation of BaSO4 precipitate: Pour the solution in the sulfur dioxide collector (5) into a beaker, add an acidic solvent to adjust the pH, then add BaCl2 solution while stirring continuously. After adding the BaCl2 solution, let it stand until BaSO4 precipitate is precipitated; S3: Preparation of BaSO4 particles: Adjust the pH of the solution after standing with ultrapure water. After adjustment, filter it with a gold-plated filter membrane with a gold layer thickness of less than 10nm. Wash the BaSO4 precipitate with ultrapure water. After filtration, obtain BaSO4 particles. Place the filter membrane with BaSO4 particles in a drying oven for drying. S5: Analysis of BaSO4 particles: Use nano-secondary ion mass spectrometry to analyze the dried BaSO4 particles, and analyze the BaSO4 standard sample and the precipitated BaSO4 particles to determine the sulfur isotope content.

6. The analytical method for measuring sulfur isotopes of sulfur dioxide in the atmosphere according to claim 5, characterized in that: The flow rate of the flow meter is 0.5 to 2 L / min.

7. The analytical method for measuring sulfur isotopes of sulfur dioxide in the atmosphere according to claim 5, characterized in that: In the S2, pH is less than 3, and the molar concentration of the BaCl2 solution is 2 mol / L.

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