WO2023093203A1 - 分形态大气汞监测设备及监测方法 - Google Patents

分形态大气汞监测设备及监测方法 Download PDF

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WO2023093203A1
WO2023093203A1 PCT/CN2022/117296 CN2022117296W WO2023093203A1 WO 2023093203 A1 WO2023093203 A1 WO 2023093203A1 CN 2022117296 W CN2022117296 W CN 2022117296W WO 2023093203 A1 WO2023093203 A1 WO 2023093203A1
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mercury
gaseous
collection
atmospheric
particulate
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PCT/CN2022/117296
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English (en)
French (fr)
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王书肖
吴清茹
汤翊
李国良
韩德明
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清华大学
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/64Fluorescence; Phosphorescence
    • G01N21/6402Atomic fluorescence; Laser induced fluorescence
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/28Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/40Concentrating samples
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/28Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/44Sample treatment involving radiation, e.g. heat
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01Arrangements or apparatus for facilitating the optical investigation
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/28Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/40Concentrating samples
    • G01N1/4005Concentrating samples by transferring a selected component through a membrane
    • G01N2001/4011Concentrating samples by transferring a selected component through a membrane being a ion-exchange membrane
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01Arrangements or apparatus for facilitating the optical investigation
    • G01N2021/0106General arrangement of respective parts
    • G01N2021/0112Apparatus in one mechanical, optical or electronic block

Definitions

  • the application relates to the technical field of environmental science analysis and environmental detection devices, in particular to a fractal atmospheric mercury monitoring device and monitoring method.
  • GEM gaseous Elemental Mercury
  • GOM gaseous Oxidized Mercury
  • PBM particulate mercury
  • GEM gaseous Elemental Mercury
  • GEM gaseous Oxidized Mercury
  • PBM particulate mercury
  • GEM has stable chemical properties, and the average residence time is between 0.5 and 2 years. It is the main component of atmospheric mercury, accounting for between 90% and 99%.
  • the chemical properties of GOM and PBM are relatively active, and the average residence time ranges from several weeks to several months.
  • GOM and PBM account for a small proportion in the atmosphere, they are the main part of atmospheric mercury deposition. GOM and PBM will fall to the surface through dry and wet deposition, and will be further transformed into highly toxic methylmercury, which seriously threatens ecological security and environmental protection. human health.
  • the existing atmospheric mercury online observation system mainly uses the corrosion tube to capture GOM, so as to obtain the concentration of GOM. During the test of the system, only the collection of GOM under pure and dry air was considered, and then the concentration of GOM was calculated.
  • the composition of the ambient atmosphere is complex, and there are interfering factors such as moisture and ozone.
  • the corrosion tube will be severely disturbed by moisture and ozone in the ambient air, resulting in a serious underestimation of the sampling efficiency in the real environment, and the concentration test error of GOM is relatively large, which cannot meet the fractal form of mercury in the ambient air. Monitor needs.
  • This application provides a monitoring device and method for monitoring atmospheric mercury in different forms, which is used to solve the defect of inaccurate detection of gaseous mercury oxide concentration in ambient air samples in different forms of mercury in the prior art, reduces the analysis error of gaseous mercury oxide, and can meet Atmospheric speciation mercury monitoring requirements under various ambient atmospheric conditions.
  • the application provides a fractal form of atmospheric mercury monitoring equipment, including:
  • a connected gaseous mercury oxide collection and thermal analysis device and a particulate mercury collection and thermal analysis device the gaseous mercury oxide collection and thermal analysis device is used to capture and analyze gaseous mercury oxide contained in ambient air samples, the granular mercury
  • the collection and thermal desorption device is used to capture and analyze the particulate mercury contained in the ambient air sample, and one of the gaseous mercury oxide collection and thermal desorption device and the particulate mercury collection and thermal desorption device is provided with a first air inlet mouth, the other is provided with a first air outlet;
  • a cold atomic fluorescence mercury detector is used to detect the concentration of mercury contained in ambient air samples.
  • the cold atomic fluorescent mercury detector is provided with a third air inlet and a third air outlet, and the third air inlet is connected to the third air outlet. Both the first air outlet and the second air outlet are connected;
  • a switching valve used to control one of the first air outlet and the second air outlet to communicate with the third air inlet.
  • the cation exchange filter device includes at least two layers of cation exchange filter membranes arranged in sequence.
  • the fractal atmospheric mercury monitoring equipment provided according to the application also includes:
  • a heat tracing pipe one end is connected to the second gas outlet, and the other end is connected to the switching valve;
  • the heating device is arranged outside the heat tracing pipe.
  • atmospheric mercury monitoring equipment According to the fractal form atmospheric mercury monitoring equipment provided in the present application, it also includes a flow meter, which is used to detect the flow of gas entering the cold atomic fluorescence mercury analyzer.
  • the fractal atmospheric mercury monitoring equipment provided by the present application, it also includes a PM 2.5 collision trap for filtering ambient air samples, and the first air inlet and/or the second air inlet are provided with the PM 2.5 Collision catcher.
  • the fractal atmospheric mercury monitoring equipment also includes a sampling control device, the sampling control device is connected with the gaseous mercury oxide collection and thermal analysis device, the particle mercury collection and thermal analysis device, the cation exchange filter The device, the cold atomic fluorescence mercury analyzer and the switching valve are all electrically connected.
  • the gaseous mercury oxide collection and thermal analysis device includes:
  • the first tubular heating assembly is arranged outside the corrosion tube, and the first tubular heating assembly is used to heat the corrosion tube to decompose the trapped gaseous mercury oxide;
  • the first temperature controller is used to control the heating temperature of the first tubular heating component and is electrically connected to the sampling control device.
  • the particulate mercury collection and thermal desorption device includes:
  • a quartz glass connecting pipe communicates with the corrosion pipe
  • a quartz cut-off filter membrane is arranged in the quartz glass connection tube for trapping particulate mercury contained in ambient air samples;
  • the second tubular heating assembly is arranged outside the quartz glass connecting pipe, the second tubular heating assembly is located at the position of the quartz glass connecting pipe close to the quartz cut-off filter membrane, and the second tubular heating assembly Used to heat the quartz glass connection tube to resolve trapped particulate mercury;
  • the second temperature controller is used to control the heating temperature of the second tubular heating assembly and is electrically connected to the sampling control device.
  • the fractal atmospheric mercury monitoring device provided in the present application further includes an air inlet valve, and an air outlet end of the air inlet valve communicates with both the first air inlet and the second air inlet.
  • the present application also provides a method for monitoring fractal atmospheric mercury, based on the fractal atmospheric mercury monitoring device described in any one of the above, comprising the steps of:
  • the gaseous mercury oxide contained in the ambient air sample is captured by the gaseous mercury oxide collection and thermal desorption device, and the particulate mercury contained in the ambient air sample is captured by the particulate mercury collection and thermal desorption device;
  • the fractal atmospheric mercury monitoring equipment includes: a connected gaseous mercury oxide collection and thermal analysis device and a particulate mercury collection and thermal analysis device, and the gaseous mercury oxide collection and thermal analysis device is used to capture and analyze ambient air samples
  • the particulate mercury collection and thermal desorption device is used to capture and analyze the particulate mercury contained in the ambient air sample, and one of the gaseous mercury oxide collection and thermal desorption device and the particulate mercury collection and thermal desorption device is set There is a first air inlet, and the other is provided with a first air outlet;
  • the cation exchange filter is used to capture the gaseous mercury oxide and particulate mercury contained in the ambient air sample, and the cation exchange filter is provided with a second air inlet and the second gas outlet;
  • the cold atomic fluorescence mercury meter is used to detect the concentration of mercury contained in the ambient air sample, the cold atom fluorescent mercury meter is provided with a third air inlet and a third air outlet, and the third air inlet It is connected with both the first
  • the gas passing through the particulate mercury collection and thermal desorption device and the gaseous mercury oxide collection and thermal desorption device contains gaseous elemental mercury and uncaptured gaseous mercury oxide, and the total mercury concentration can be measured by a cold atomic fluorescence mercury detector.
  • the gas passing through the cation exchange filter device only contains gaseous elemental mercury, and the concentration of gaseous elemental mercury can be measured by a cold atomic fluorescence mercury analyzer.
  • different forms of mercury can be captured, and the concentration of gaseous mercury oxide can be accurately calculated by combining zero gas purge analysis and difference method, which greatly reduces the analysis error of gaseous mercury oxide and can meet the requirements of various environmental and atmospheric conditions. The need for accurate monitoring of mercury in atmospheric species.
  • Fig. 1 is the structural representation of the fractal atmospheric mercury monitoring equipment that the application provides;
  • Fig . 2 is the atmospheric zero-valent mercury analysis unit of the present application to HgBr under clean air conditions Schematic diagram comparing the capture efficiency with the test results of the prior art
  • Fig. 3 is a schematic diagram of the comparison between the atmospheric mercury concentration in Beijing detected by the atmospheric mercury monitoring equipment of the present application and the test results of the prior art;
  • 11 Granular mercury collection and thermal analysis device
  • 111 Quartz glass connecting pipe
  • 112 Second tubular heating component
  • 113 second temperature controller
  • 114 quartz cut-off filter membrane
  • 12 gaseous mercury oxide collection and thermal analysis device
  • 121 corrosion tube
  • 122 first tubular heating component
  • 123 first temperature controller
  • the embodiment of the present application provides a fractal atmospheric mercury monitoring device, including a particle mercury collection and thermal analysis device 11, a gaseous mercury oxide collection and thermal analysis device 12, a cation exchange filter device 23, a cold atomic fluorescence Mercury meter 15 and switching valve 25.
  • the particle mercury collection and thermal analysis device 11 and the gaseous mercury oxidation collection and thermal analysis device 12 are connected.
  • the particle mercury collection and thermal analysis device 11 is used to capture and analyze the particulate mercury contained in the ambient air sample, and the gaseous mercury oxidation
  • the mercury collection and thermal analysis device 12 is used to capture and analyze gaseous mercury oxide contained in ambient air samples.
  • One of the particle mercury collection and thermal analysis device 11 and the gaseous mercury oxide collection and thermal analysis device 12 is provided with a first gas inlet, and the other is provided with a first gas outlet.
  • the gaseous mercury oxide collection and thermal analysis device 12 is provided with a first air inlet
  • the particulate mercury collection and thermal analysis device 11 is provided with a first gas outlet.
  • an air pump 142 is also provided, and the air pump 142 can be connected to the first air outlet, so that ambient air samples can enter the monitoring device.
  • the air pump 142 can also be connected to the first air inlet, so that ambient air samples can enter the monitoring device.
  • the gas pump 142 can also be used to bring a zero gas source into the monitoring device to enable desorption of trapped gaseous oxidized mercury and particulate mercury.
  • the cation exchange filter device 23 is used to trap gaseous oxidized mercury and particulate mercury contained in the ambient air sample.
  • the cation exchange filter device 23 is provided with a second air inlet and a second gas outlet for the ambient air sample to pass through.
  • the cold atomic fluorescence mercury analyzer 15 is used to detect the concentration of mercury contained in ambient air samples.
  • the cold atomic fluorescence mercury detector 15 is an existing mature product, which includes a gold tube enrichment component 151, a mercury excitation test device 152 and a vacuum pump 153. Adjusting the flow rate of the vacuum pump 153 can extract a certain amount of gas for detection.
  • the cold atomic fluorescence mercury meter 15 is provided with a third air inlet and a third air outlet, and the third air inlet is connected with the first air outlet and the second air outlet.
  • the switching valve 25 is used to control one of the first air outlet and the second air outlet to communicate with the third air inlet, and can be an electronic timing three-way switching valve. Specifically, the first inlet of the three-way switching valve with electronic timing is connected to the first gas outlet, the second inlet is connected to the second gas outlet, and the outlet is connected to the third gas inlet.
  • the cold atomic fluorescence mercury detector 15 can collect and thermally analyze the particulate mercury through the device 11 and The gaseous mercury oxide is collected and detected after the thermal analysis device 12.
  • the second inlet and outlet of the electronic timing three-way switching valve are connected, that is, the second gas outlet is connected with the third air inlet, the cold atomic fluorescence mercury detector 15 can perform a measurement on the gas after passing through the cation exchange filter device 23 detection.
  • the electronic timing three-way switching valve can switch between the two channels at a certain time interval according to the detection requirements, so that the sampling program can be repeated at a fixed time interval, which improves the convenience of using the online analysis program.
  • the specific time interval shall be determined according to the actual sampling requirements.
  • the ambient air sample of the intake valve enters the gaseous mercury oxide collection and thermal analysis device 12 and the particle mercury collection and thermal analysis device 11, along the direction indicated by the arrow in Figure 1, and is finally discharged through the air pump 142 .
  • the GOM and PBM contained in the ambient air sample are then trapped, and the GEM and untrapped GOM are discharged.
  • the switching valve 25 connects the first gas outlet with the third gas inlet, extracts a certain amount of gas from the exhaust pipeline, and measures the total concentration of mercury, that is, the total concentration of GEM and uncaptured GOM.
  • the switching valve 25 connects the second gas outlet with the third gas inlet, and the ambient air sample enters the cation exchange filter device 23 and is finally discharged through the cold atomic fluorescence mercury analyzer 15 .
  • the GOM and PBM contained in the ambient air sample are completely absorbed by the cation exchange filter membrane, and only GEM is contained in the discharged gas, so that the concentration of GEM can be measured.
  • the gaseous mercury oxide collection and thermal desorption device 12 and the particulate mercury collection and thermal desorption device 11 are subjected to a zero gas purging test to analyze GOM and PBM, and measure the concentration of GOM and PBM.
  • the difference method can be used to accurately obtain the actual GOM concentration, so as to accurately obtain the GEM concentration, GOM concentration and PBM concentration in the ambient air sample respectively. It should be noted that, under clean air conditions, when the zero air purging test is performed, the mercury concentration contained in the zero air entering the monitoring equipment should be zero to reduce the calculation error of the GOM concentration.
  • the gas passing through the particle mercury collection and thermal analysis device 11 and the gaseous mercury oxide collection and thermal analysis device 12 contains gaseous elemental mercury and uncaptured gaseous mercury oxide
  • the gas passing through the cation exchange filter device 23 only contains gaseous elemental mercury . Therefore, different forms of mercury can be captured, and the concentration of gaseous mercury oxide can be accurately calculated in combination with zero gas purging analysis and difference method.
  • the embodiment of the present application uses a cation exchange filter membrane to capture gaseous oxidized mercury online. Compared with the existing online mercury monitoring instrument, it minimizes the impact of the chemical reaction of GOM on the corrosion tube on the GOM concentration test. Improved monitoring accuracy.
  • the monitoring equipment for atmospheric mercury in different forms in this embodiment not only has good consistency and stability, but also greatly reduces the analysis error of gaseous mercury oxide, and can meet the requirements for accurate monitoring of atmospheric mercury in various atmospheric conditions. It provides a reliable basis for understanding the characteristics of atmospheric mercury pollution, and further analyzing the transformation of atmospheric mercury species and the mass balance of atmospheric mercury.
  • the cation-exchange filter device 23 includes at least two layers of cation-exchange filter membranes arranged in sequence to ensure complete absorption of gaseous oxidized mercury and particulate mercury.
  • the cation exchange filter membrane is made of PFA (Polytetrafluoroethylene, meltable polytetrafluoroethylene) material, and its diameter may be 47 mm, and its specific size may be determined according to actual usage requirements. It should be noted that every two weeks of use, it is necessary to check and replace the two layers of cation exchange filter membranes to ensure that the cation exchange filter membranes are in good working condition.
  • PFA Polytetrafluoroethylene, meltable polytetrafluoroethylene
  • the atmospheric zero-valent mercury analysis unit 2 also includes a heat tracing pipe 24 and a heating device arranged outside the heat tracing pipe 24.
  • One end of the heat tracing pipe 24 is connected to the second gas outlet of the cation exchange filter device 23 , and the other end is connected to the switching valve 25 .
  • the heat tracing pipe 24 can be a PFA pipe with an inner diameter of 1/4 foot, and its specific size and the like can be determined according to actual use requirements.
  • the heating device can be a heating wire wrapped around the outside of the tube, which can keep the temperature of the heat tracing tube 24 at 120°C, avoiding problems such as pipeline blockage caused by dew generated by indoor and outdoor temperature differences.
  • the heating device should have a waterproof function to ensure that the pipeline can be used for a long time.
  • PFA threaded joints can be used at the connection positions of each pipeline to ensure firm connection, excellent air tightness, and not be affected by the heat preservation of the heat tracing pipe 24, so that mercury in different forms can be captured stably and efficiently.
  • the fractal atmospheric mercury monitoring equipment further includes a flow meter 26 for detecting the gas flow rate entering the cold atomic fluorescence mercury detector 15 .
  • the flow meter 26 can be arranged at the third air inlet of the cold atomic fluorescence mercury analyzer 15, or at the third air outlet. In this way, when the switching valve 25 switches the two paths, it can be monitored whether the test flows of the two paths are the same, so as to facilitate accurate comparison and ensure the test accuracy.
  • the fractal atmospheric mercury monitoring equipment also includes a PM 2.5 collision trap 13 for filtering ambient air samples, and the PM 2.5 collision trap 13 is arranged at the first air inlet and/or the second inlet Intake valve at the air port.
  • ambient air samples can be filtered to prevent impurities from entering the monitoring equipment to block the pipeline and prolong the service life of the equipment.
  • the fractal atmospheric mercury monitoring equipment also includes a sampling control device 141, a sampling control device 141, a gaseous mercury oxide collection and thermal analysis device 12, a particulate mercury collection and thermal analysis device 11, an air intake valve, and a cation exchange filter device 23.
  • the cold atomic fluorescence mercury measuring instrument 15 and the switching valve 25 are all electrically connected. In this way, the intelligent automatic control of the sampling program is realized, and each process is carried out in an orderly manner, which improves the efficiency of online monitoring.
  • the gaseous mercury oxide collection and thermal analysis device 12 includes a corrosion pipe 121 , a first tubular heating component 122 , and a first temperature controller 123 .
  • the gas inlet valve of the dissolution pipe 121 is used for the entry of ambient air samples, and is used to capture gaseous oxidized mercury contained in the ambient air samples.
  • the first tubular heating component 122 is arranged outside the corrosion pipe 121, and can heat the corrosion pipe 121 during zero gas purging, so as to analyze the trapped gaseous mercury oxide, so as to detect the concentration of gaseous mercury oxide.
  • the first temperature controller 123 is used to control the heating temperature of the first tubular heating assembly 122 and is electrically connected to the sampling control device 141 , so as to realize automatic control of the heating temperature of the erosion tube 121 .
  • the temperature should be controlled within the range of 500°C-700°C, optionally, the temperature is set to 500°C ⁇ 10°C.
  • the air flow setting range of the zero air purge is 6LPM-8LPM, and optionally, the flow rate of the zero air purge is set to 7LPM.
  • LPM is the flow unit, ie liters per minute.
  • the particle mercury collection and thermal analysis device 11 includes a quartz glass connecting pipe 111 , a second tubular heating assembly 112 , a second temperature controller 113 , and a quartz cut-off filter membrane 114 .
  • the quartz glass connection pipe 111 communicates with the corrosion pipe 121 for the entry of ambient air samples.
  • the quartz cut-off filter membrane 114 is arranged in the quartz glass connecting pipe 111, and is used for trapping particulate mercury contained in ambient air samples.
  • the second tubular heating assembly 112 is disposed outside the quartz glass connecting pipe 111 and is located near the quartz cut-off filter membrane 114 .
  • the quartz glass connection pipe 111 is heated to analyze the trapped particulate mercury, thereby measuring the particulate mercury concentration.
  • the second temperature controller 113 is used to control the heating temperature of the second tubular heating assembly 112, and is electrically connected with the sampling control device 141, so as to realize automatic heating according to the sampling program.
  • the temperature should be controlled within the range of 800°C-1000°C, and optionally, the temperature is set to 800°C ⁇ 10°C.
  • the fractal atmospheric mercury monitoring equipment also includes an air inlet valve 21, and the air outlet end of the air inlet valve 21 is connected with the first air inlet and the second air inlet to ensure that the two passages share one inlet. Gas port to ensure test accuracy and consistency.
  • the inlet valve 21 can be a quartz three-way inlet valve, the inlet end of which is connected to the air source, and the two outlet ends are respectively connected to the first inlet and the second inlet, and it is necessary to ensure that the airtightness of the interface is good .
  • the quartz three-way inlet valve and the second inlet of the cation exchange filter device 23 are connected through a Teflon connecting pipeline 22, which has high chemical stability and excellent aging resistance, It can be used outdoors for a long time.
  • the fractal atmospheric mercury monitoring method provided by this application is described below, and the fractal atmospheric mercury monitoring method described below and the fractal atmospheric mercury monitoring equipment described above can be referred to each other.
  • the embodiment of the present application also provides a method for monitoring fractal atmospheric mercury, based on the fractal atmospheric mercury monitoring equipment in the above-mentioned embodiments, comprising steps:
  • the gaseous mercury oxide contained in the ambient air sample is captured by the gaseous mercury oxide collection and thermal desorption device 12, and the particulate mercury contained in the ambient air sample is captured by the particulate mercury collection and thermal desorption device 11; specifically, as shown in Figure 1 As shown, the ambient air samples pass through the gaseous mercury oxide collection and thermal desorption device 12 and the particulate mercury collection and thermal desorption device 11 in sequence to capture gaseous mercury oxide and particulate mercury respectively;
  • the total concentration of mercury in the ambient air sample after passing through the gaseous mercury oxide collection and thermal desorption device 12 and the particulate mercury collection and thermal desorption device 11, wherein the total mercury concentration is the gaseous elemental mercury and the uncaptured gaseous mercury oxide Total concentration;
  • the first gas outlet is controlled to communicate with the third air inlet by the switching valve 25, and the total concentration of mercury is detected by the cold atomic fluorescence mercury analyzer 15;
  • Analyzing the gaseous mercury oxide captured by the gaseous mercury oxide collection and thermal analysis device 12, and obtaining the concentration of the captured gaseous mercury oxide Specifically, the gaseous mercury oxide collection and thermal analysis device 12 is purged with zero gas to analyze the gaseous mercury oxide.
  • the connection between the first gas outlet and the third gas inlet is controlled by a switching valve 25 , and the concentration of decomposed gaseous mercury oxide is detected by a cold atomic fluorescence mercury analyzer 15 .
  • particulate mercury collection and thermal analysis device 11 can also be purged with zero gas to analyze the particulate mercury. And the concentration of the analyzed particulate mercury is detected by a cold atomic fluorescence mercury analyzer 15 .
  • the single sampling process of the fractal atmospheric mercury monitoring equipment is two hours, and it can analyze gaseous elemental mercury, gaseous oxidized mercury and particulate mercury in the atmosphere with a high time resolution of two hours.
  • the test methods of gaseous mercury oxide and particulate mercury are the corrosion tube method and the quartz filter method respectively, and the operation and maintenance requirements need to be strictly implemented in accordance with international standard operating procedures.
  • the specific implementation process of the fractal atmospheric mercury monitoring method is as follows:
  • the particulate mercury collection and thermal analysis device 11 and the gaseous mercury oxide collection and thermal analysis device 12 collect ambient air for 20 minutes;
  • the cation exchange filter device 23 collects ambient air for 20 minutes;
  • Gaseous mercury oxide collection and thermal desorption device 12 and particle mercury collection and thermal desorption device 11 collect ambient air, and the duration is 20 minutes;
  • the particle mercury collection and thermal analysis device 11 and the gaseous mercury oxide collection and thermal analysis device 12 analyze the particulate mercury and gaseous mercury oxide for 60 minutes. Wherein, in the analysis process, the particulate mercury collection and thermal analysis device 11 is first heated to analyze the particulate mercury. Then the gaseous mercury oxide collection and thermal analysis device 12 is heated to analyze the gaseous mercury oxide.
  • the total flow rate of the ambient air collected by the particle mercury collection and thermal desorption device 11 and the gaseous mercury oxide collection and thermal desorption device 12 is set to a range of 5LPM-15LPM.
  • the pump flow rate is set to 9LPM.
  • the flow setting range of the cold atomic fluorescence mercury analyzer 15 is 0.5LPM-1.5LPM, and optionally, the pump flow is set to 1LPM.
  • a mercury concentration data can be collected and analyzed every 5 minutes, a total of 24 concentration data can be analyzed, and a component form of mercury data can be obtained after sorting and calculation.
  • the sampling results are shown in Table 1.
  • GEM is the current two-hour cycle gaseous elemental mercury concentration in ng m -3 .
  • TEK-GOM is the current two-hour cycle gaseous mercury oxide concentration in ng m -3 based on the erosion tube method.
  • GOM is the concentration of gaseous mercury oxide in the current two-hour cycle calculated by subtraction method, and the unit is ng m -3 .
  • PBM is the current two-hour cycle particulate mercury concentration in ng m -3 based on the quartz filter method.
  • This application can carry out more accurate capture analysis and concentration analysis of mercury in different types of ambient air samples, and capture all the gaseous mercury oxide and particulate mercury in the ambient air samples through the cation exchange filter device 23 based on ion exchange membrane, and the remaining
  • the gaseous elemental mercury in the gaseous state enters the cold atomic fluorescence mercury detector 15 for determination, and the gaseous total mercury obtained through the particle mercury collection and thermal analysis device 11 and the gaseous mercury oxide collection and thermal analysis device 12 and the gaseous elemental mercury obtained through the ion exchange membrane are carried out.
  • Comparison to achieve accurate measurement of gaseous mercury oxide under the state of high time resolution atmospheric mercury determination.
  • the fractal-form atmospheric mercury monitoring equipment of the application and the existing online fractal-form mercury monitoring instrument were used to analyze the atmospheric mercury concentration in the urban area of Beijing during September 10, 2021-September 30, 2021. Form mercury was collected and analyzed online. Comparing the sampling results, the comparison results are shown in Figure 3.
  • the concentrations of GEM, GOM and PBM obtained in the test of this application are 3.02 ⁇ 1.21ng m -3 , 0.44 ⁇ 0.42ng m -3 , and 0.056 ⁇ 0.10ng m -3 , respectively.
  • the GOM concentration measured by the existing online speciation mercury monitoring instrument is 0.20 ⁇ 0.22ng m -3 .
  • the present application also uses pure HgBr 2 gas to test the capture efficiency of the ion-exchange membrane-based cation exchange filter device 23 for HgBr 2 .
  • the tested HgBr 2 concentration is 1.3 ⁇ 0.1ng m -3 , which is higher than the active gaseous mercury concentration in general atmospheric environment.
  • the capture efficiency of HgBr 2 was tested using two existing on-line fractal mercury monitors based on corrosion tubes. The test results are compared, and the comparison results are shown in Figure 2. It can be clearly seen from Fig.
  • the test results of the present application show that the cation exchange filter device 23 based on the ion exchange membrane can absorb divalent mercury with an efficiency of 100% ⁇ 9%, compared to existing Commonly used instruments, HgBr 2 capture efficiency increased by 40%. Therefore, it is shown that the cation exchange filter device 23 based on the ion exchange membrane of the present application has better trapping performance of active gaseous mercury.
  • this application provides a new type of monitoring equipment and method for fractal atmospheric mercury, including a particulate mercury collection and thermal analysis device 11, a gaseous mercury oxide collection and thermal analysis device 12, and a cation exchange membrane based ion exchange membrane.
  • Filtration device 23 The gaseous total mercury and gaseous elemental mercury are collected by two units respectively, and the actual concentration of gaseous mercury oxide in the atmosphere is calculated by comparing the results of the two channels, which solves the problem of inaccurate detection of the gaseous mercury oxide concentration in the different forms of mercury in the existing ambient air samples . Its time resolution is high, and it can be widely used in various types of ambient atmospheres to efficiently, stably, and conveniently capture atmospheric mercury in various forms, improving online monitoring efficiency and testing accuracy.

Abstract

一种分形态大气汞监测设备及监测方法,包括气态氧化汞采集与热解析装置(12)、颗粒汞采集与热解析装置(11)、阳离子交换过滤装置(23)、冷原子荧光测汞仪(15)和切换阀(25),经过气态氧化汞采集与热解析装置(12)和颗粒汞采集与热解析装置(11)的气体含有气态元素汞和未捕集的气态氧化汞,可测出总汞浓度,经过阳离子交换过滤装置(11)的气体仅含有气态元素汞,可测出气态元素汞,从而可对不同形态的汞进行捕集,并结合零气吹扫解析和差值法准确计算出气态氧化汞浓度,大大降低了气态氧化汞的分析误差,满足各种环境大气条件下大气分形态汞准确监测需求。

Description

分形态大气汞监测设备及监测方法
相关申请的交叉引用
本申请要求于2021年11月24日提交的申请号为202111406566.0,发明名称为“分形态大气汞监测设备及监测方法”的中国专利申请的优先权,其通过引用方式全部并入本文。
技术领域
本申请涉及环境科学分析与环境检测装置技术领域,尤其涉及一种分形态大气汞监测设备及监测方法。
背景技术
汞为全球性污染物,对环境和人体健康具有极大的危害。大气中有三种形态的汞,分别是气态元素汞(Gaseous Elemental Mercury,GEM)、气态氧化汞(Gaseous Oxidized Mercury,GOM)和颗粒汞(Particulate Bounded Mercury,PBM)。其中GEM化学性质稳定,停留时间平均在0.5年-2年之间,是大气汞的主要成分,占比在90%-99%之间。而GOM和PBM化学性质相对活泼,平均停留时间在几周-几个月不等。GOM和PBM在大气中虽然占比较小,却是大气汞沉降的主要部分,GOM和PBM会通过干沉降和湿沉降落到地表,并进一步转化成为剧毒的甲基汞,严重威胁生态安全和人体健康。
现有的大气分形态汞在线观测系统主要采用溶蚀管捕集GOM,从而得出GOM的浓度。该系统测试时仅考虑了纯净干燥的空气下对GOM的采集,进而计算出GOM的浓度。
但是,环境大气中的成分复杂,存在如水分和臭氧等干扰因素。而在对环境空气检测时,溶蚀管会在环境空气中受到水分和臭氧的严重干扰,导致真实环境下的采样效率严重低估,GOM的浓度测试误差较大,无法满足环境空气下的分形态汞监测需求。
因此,亟需提供一种适用于环境大气观测且精准观测GOM的大气分形态汞观测仪器,成为本领域技术人员所要解决的重要技术问题。
发明内容
本申请提供一种分形态大气汞监测设备及监测方法,用以解决现有技术中环境大气样品分形态汞中气态氧化汞浓度检测不准确的缺陷,降低了气态氧化汞的分析误差,可以满足各种环境大气条件下的大气分形态汞监测需求。
本申请提供一种分形态大气汞监测设备,包括:
相连通的气态氧化汞采集与热解析装置和颗粒汞采集与热解析装置,所述气态氧化汞采集与热解析装置用于捕集和解析环境大气样品中含有的气态氧化汞,所述颗粒汞采集与热解析装置用于捕集和解析环境大气样品中含有的颗粒汞,所述气态氧化汞采集与热解析装置和所述颗粒汞采集与热解析装置二者之一设有第一进气口、另一者设有第一出气口;
阳离子交换过滤装置,用于捕集环境大气样品中含有的气态氧化汞和颗粒汞,所述阳离子交换过滤装置设有第二进气口和第二出气口;
冷原子荧光测汞仪,用于检测环境大气样品中含有的汞的浓度,所述冷原子荧光测汞仪设有第三进气口和第三出气口,所述第三进气口与所述第一出气口和所述第二出气口均相连接;
切换阀,用于控制所述第一出气口和所述第二出气口中的一者与所述第三进气口相连通。
根据本申请提供的分形态大气汞监测设备,所述阳离子交换过滤装置包括至少两层依次设置的阳离子交换过滤膜。
根据本申请提供的分形态大气汞监测设备,还包括:
伴热管,一端与所述第二出气口相连接、另一端与所述切换阀相连接;
加热装置,设置在所述伴热管外。
根据本申请提供的分形态大气汞监测设备,还包括流量计,用于检测进入所述冷原子荧光测汞仪的气体流量。
根据本申请提供的分形态大气汞监测设备,还包括PM 2.5碰撞捕集器,用于过滤环境大气样品,所述第一进气口和/或所述第二进气口设有所述PM 2.5碰撞捕集器。
根据本申请提供的分形态大气汞监测设备,还包括采样控制装置,所述采样控制装置与所述气态氧化汞采集与热解析装置、所述颗粒汞采集与 热解析装置、所述阳离子交换过滤装置、所述冷原子荧光测汞仪和所述切换阀均电连接。
根据本申请提供的分形态大气汞监测设备,所述气态氧化汞采集与热解析装置包括:
溶蚀管,用于捕集环境大气样品中含有的气态氧化汞;
第一管式加热组件,设置在所述溶蚀管外,所述第一管式加热组件用于加热所述溶蚀管,以解析捕集的气态氧化汞;
第一温度控制仪,用于控制所述第一管式加热组件的加热温度,且与所述采样控制装置电连接。
根据本申请提供的分形态大气汞监测设备,所述颗粒汞采集与热解析装置包括:
石英玻璃连接管,与所述溶蚀管相连通;
石英截流滤膜,设置在所述石英玻璃连接管内,用于捕集环境大气样品中含有的颗粒汞;
第二管式加热组件,设置在所述石英玻璃连接管外,所述第二管式加热组件位于所述石英玻璃连接管靠近所述石英截流滤膜的位置,所述第二管式加热组件用于加热所述石英玻璃连接管,以解析捕集的颗粒汞;
第二温度控制仪,用于控制所述第二管式加热组件的加热温度,且与所述采样控制装置电连接。
根据本申请提供的分形态大气汞监测设备,还包括进气阀,所述进气阀的出气端与所述第一进气口和所述第二进气口均相连通。
本申请还提供一种分形态大气汞监测方法,基于如上任一项所述的分形态大气汞监测设备,包括步骤:
采集环境大气样品;
通过气态氧化汞采集与热解析装置捕集环境大气样品中含有的气态氧化汞,并通过颗粒汞采集与热解析装置捕集环境大气样品中含有的颗粒汞;
获取经过气态氧化汞采集与热解析装置和颗粒汞采集与热解析装置后的环境大气样品中汞的总浓度,其中,汞的总浓度为气态元素汞和未捕集的气态氧化汞的总浓度;
通过阳离子交换过滤装置捕集环境大气样品中含有的气态氧化汞和颗 粒汞;
获取经过阳离子交换过滤装置后的环境大气样品中气态元素汞的浓度;
比较汞的总浓度和气态元素汞的浓度,并获取汞的总浓度与气态元素汞的浓度的差值,以得到未捕集的气态氧化汞的浓度;
解析气态氧化汞采集与热解析装置捕集的气态氧化汞,并获取捕集的气态氧化汞的浓度。
本申请提供的分形态大气汞监测设备,包括:相连通的气态氧化汞采集与热解析装置和颗粒汞采集与热解析装置,气态氧化汞采集与热解析装置用于捕集和解析环境大气样品中含有的气态氧化汞,颗粒汞采集与热解析装置用于捕集和解析环境大气样品中含有的颗粒汞,气态氧化汞采集与热解析装置和颗粒汞采集与热解析装置二者之一设有第一进气口、另一者设有第一出气口;阳离子交换过滤装置,用于捕集环境大气样品中含有的气态氧化汞和颗粒汞,阳离子交换过滤装置设有第二进气口和第二出气口;冷原子荧光测汞仪,用于检测环境大气样品中含有的汞的浓度,冷原子荧光测汞仪设有第三进气口和第三出气口,第三进气口与第一出气口和第二出气口均相连接;切换阀,用于控制第一出气口和第二出气口中的一者与第三进气口相连通。
如此设置,经过颗粒汞采集与热解析装置和气态氧化汞采集与热解析装置的气体含有气态元素汞和未被捕集的气态氧化汞,可通过冷原子荧光测汞仪测出总汞浓度。经过阳离子交换过滤装置的气体仅含有气态元素汞,可通过冷原子荧光测汞仪测出气态元素汞浓度。从而实现对不同形态的汞进行捕集,并结合零气吹扫解析和差值法可以准确计算出气态氧化汞的浓度,大大降低了气态氧化汞的分析误差,可以满足各种环境大气条件下的大气分形态汞准确监测需求。
附图说明
为了更清楚地说明本申请或现有技术中的技术方案,下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图是本申请的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据这些附图获得其他的附图。
图1是本申请提供的分形态大气汞监测设备的结构示意图;
图2是本申请的大气零价汞分析单元在洁净空气条件下对HgBr 2的捕集效率与现有技术的测试结果对比示意图;
图3是本申请的分形态大气汞监测设备检测的北京大气分形态汞浓度与现有技术的测试结果对比示意图;
附图标记:
11:颗粒汞采集与热解析装置;111:石英玻璃连接管;112:第二管式加热组件;
113:第二温度控制仪;114:石英截流滤膜;12:气态氧化汞采集与热解析装置
121:溶蚀管;122:第一管式加热组件;123:第一温度控制仪;
13:PM 2.5碰撞捕集器;141:采样控制装置;142:气泵;
15:冷原子荧光测汞仪;151:金管富集组件;152:汞激发测试装置;
153:真空泵;21:进气阀;22:特氟龙连接管路;
23:阳离子交换过滤装置;24:伴热管;25:切换阀;
26:流量计。
具体实施方式
为使本申请的目的、技术方案和优点更加清楚,下面将结合本申请中的附图,对本申请中的技术方案进行清楚、完整地描述,显然,所描述的实施例是本申请一部分实施例,而不是全部的实施例。基于本申请中的实施例,本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例,都属于本申请保护的范围。
下面结合图1至图3描述本申请的分形态大气汞监测设备。
如图1所示,本申请实施例提供了一种分形态大气汞监测设备,包括颗粒汞采集与热解析装置11、气态氧化汞采集与热解析装置12、阳离子交换过滤装置23、冷原子荧光测汞仪15和切换阀25。具体来说,颗粒汞采集与热解析装置11和气态氧化汞采集与热解析装置12相连通,颗粒汞采 集与热解析装置11用于捕集和解析环境大气样品中含有的颗粒汞,气态氧化汞采集与热解析装置12用于捕集和解析环境大气样品中含有的气态氧化汞。颗粒汞采集与热解析装置11和气态氧化汞采集与热解析装置12二者之一设有第一进气口,另一者设有第一出气口。具体地,如图1所示,气态氧化汞采集与热解析装置12设有第一进气口,颗粒汞采集与热解析装置11设有第一出气口。此外,还设有气泵142,气泵142可以和第一出气口相连接,以使环境大气样品进入监测设备。当然,也可将气泵142与第一进气口相连接,以使环境大气样品进入监测设备。另外,气泵142还可用于使零气源进入监测设备,以能够解析捕集的气态氧化汞和颗粒汞。
阳离子交换过滤装置23用于捕集环境大气样品中含有的气态氧化汞和颗粒汞,阳离子交换过滤装置23设有第二进气口和第二出气口,以供环境大气样品通过。冷原子荧光测汞仪15用于检测环境大气样品中含有的汞的浓度。冷原子荧光测汞仪15为现有成熟产品,包括金管富集组件151、汞激发测试装置152和真空泵153,调节真空泵153的流量,可抽取一定量气体进行检测。冷原子荧光测汞仪15设有第三进气口和第三出气口,第三进气口与第一出气口和第二出气口均相连接。切换阀25用于控制第一出气口和第二出气口中的一者与第三进气口相连通,可为电子计时三通切换阀。具体地,电子计时三通切换阀的第一进口和第一出气口相连,第二进口和第二出气口相连,出口和第三进气口相连。当电子计时三通切换阀的第一进口和出口导通时,即第一出气口和第三进气口相连通,冷原子荧光测汞仪15可对经过颗粒汞采集与热解析装置11和气态氧化汞采集与热解析装置12后的气体进行检测。当电子计时三通切换阀的第二进口和出口导通时,即第二出气口和第三进气口相连通,冷原子荧光测汞仪15可对经过阳离子交换过滤装置23后的气体进行检测。电子计时三通切换阀可根据检测需求以一定时间间隔在两个通路之间切换,以使采样程序能够以固定时间间隔循环往复,提高了在线分析程序使用的方便性。其具体时间间隔需根据实际采样要求而定。
检测时,如图1所示进气阀环境大气样品进入气态氧化汞采集与热解析装置12和颗粒汞采集与热解析装置11,沿图1中箭头所示方向,最终经过气泵142向外排出。则环境大气样品中含有的GOM和PBM被捕集, GEM和未捕集的GOM排出。此时切换阀25将第一出气口和第三进气口相连通,从排气管路抽取一定气体,测出总汞浓度即GEM和未捕集的GOM的总浓度。然后,切换阀25将第二出气口和第三进气口相连通,环境大气样品进入阳离子交换过滤装置23,最终经过冷原子荧光测汞仪15排出。通过阳离子交换过滤膜完全吸收环境大气样品中含有的GOM和PBM,排出的气体中仅含有GEM,从而可测出GEM的浓度。然后对气态氧化汞采集与热解析装置12和颗粒汞采集与热解析装置11进行零气吹扫测试,解析GOM和PBM,并测出GOM的浓度和PBM的浓度。再采用差值法即可准确获取实际GOM浓度,从而分别精确地得出环境大气样品中的GEM浓度、GOM浓度和PBM浓度。需要说明的是,在洁净空气条件下,进行零气吹扫测试时,进入监测设备中的零空气中含有的汞浓度应为零,以减小GOM浓度的计算误差。
如此设置,经过颗粒汞采集与热解析装置11和气态氧化汞采集与热解析装置12的气体含有气态元素汞和未捕集的气态氧化汞,经过阳离子交换过滤装置23的气体仅含有气态元素汞。从而对不同形态的汞进行捕集,并结合零气吹扫解析和差值法可以准确计算出气态氧化汞的浓度。本申请实施例利用阳离子交换过滤膜在线捕集气态氧化汞,相比于现有的在线分形态汞监测仪器,最大程度地降低了GOM在溶蚀管上的化学反应对GOM浓度测试产生的影响,提高了监测准确性。本实施例中的分形态大气汞监测设备不仅具有良好的一致性和稳定性,而且大大降低了气态氧化汞的分析误差,可以满足各种环境大气条件下的大气分形态汞准确监测需求。为了解大气汞污染特征,以及进一步分析大气汞形态转化和大气汞物质平衡,提供了可靠依据。
本申请实施例中,阳离子交换过滤装置23包括至少两层依次设置的阳离子交换过滤膜,以确保气态氧化汞和颗粒汞被完全吸收。具体地,阳离子交换过滤膜为PFA(Polytetrafluoro ethylene,可熔性聚四氟乙烯)材质,直径可为47毫米,其具体尺寸等可根据实际使用需求而定。需要说明的是,每使用半个月,需要检查并更换两层阳离子交换过滤膜,以确保阳离子交换过滤膜处于良好的工作状态。
本申请实施例中,大气零价汞分析单元2还包括伴热管24和设置在 伴热管24外的加热装置。伴热管24的一端与阳离子交换过滤装置23的第二出气口相连接,另一端与切换阀25相连接。伴热管24可为1/4英尺内径的PFA管,其具体尺寸等可根据实际使用需求而定。加热装置可为包绕在管外的加热丝,能够使伴热管24温度保持在120℃,避免因室内外温差产生的露水造成管路堵塞等问题。而且加热装置应具有防水功能,保证管路能长期使用。此外,各个管路的连接位置处可采用PFA螺纹接口,保证连接牢固,气密性优良,且不受伴热管24保温的影响,从而可以稳定、高效地捕集分形态汞。
本申请实施例中,分形态大气汞监测设备还包括流量计26,用于检测进入冷原子荧光测汞仪15的气体流量。具体地,流量计26可设置在冷原子荧光测汞仪15的第三进气口处,或者设置在第三出气口处。这样,在切换阀25切换两个通路时,可以监控两路测试流量是否相同,以便于进行精确对比,保证测试精度。
本申请实施例中,分形态大气汞监测设备还包括PM 2.5碰撞捕集器13,用于过滤环境大气样品,PM 2.5碰撞捕集器13设置在第一进气口处和/或第二进气口处进气阀。这样可对环境大气样品进行过滤,防止杂质进入监测设备后堵塞管路,延长设备的使用寿命。
本申请实施例中,分形态大气汞监测设备还包括采样控制装置141,采样控制装置141与气态氧化汞采集与热解析装置12、颗粒汞采集与热解析装置11进气阀、阳离子交换过滤装置23、冷原子荧光测汞仪15和切换阀25均电连接。从而实现采样程序智能自动化控制,各个过程有序进行,提高在线监测效率。
本申请实施例中,气态氧化汞采集与热解析装置12包括溶蚀管121,第一管式加热组件122,以及第一温度控制仪123。如图1所示,溶蚀管121进气阀供环境大气样品进入,用于捕集环境大气样品中含有的气态氧化汞。第一管式加热组件122设置在溶蚀管121外,在零气吹扫时,可对溶蚀管121加热,从而解析捕集的气态氧化汞,以便检测气态氧化汞浓度。第一温度控制仪123用于控制第一管式加热组件122的加热温度,且与采样控制装置141电连接,从而实现溶蚀管121加热温度的自动控制。一般地,在解析气态氧化汞时,温度应控制在500℃-700℃范围内,可选地,温 度设置为500℃±10℃。此时的零空气吹扫的气流量设置范围为6LPM-8LPM,可选地,零空气吹扫流量设置为7LPM。其中,LPM为流量单位,即升/分钟。
本申请实施例中,颗粒汞采集与热解析装置11包括石英玻璃连接管111,第二管式加热组件112,第二温度控制仪113,以及石英截流滤膜114。具体地,石英玻璃连接管111与溶蚀管121相连通,以供环境大气样品进入。石英截流滤膜114设置在石英玻璃连接管111内,用于捕集环境大气样品中含有的颗粒汞。第二管式加热组件112设置在石英玻璃连接管111外,并位于靠近石英截流滤膜114的位置。在零气吹扫时,对石英玻璃连接管111进行加热,解析捕集的颗粒汞,从而测得颗粒汞浓度。第二温度控制仪113用于控制第二管式加热组件112的加热温度,且与采样控制装置141电连接,以便根据采样程序实现自动加热。一般地,在解析颗粒汞时,温度应控制在800℃-1000℃范围内,可选地,温度设置为800℃±10℃。
本申请实施例中,分形态大气汞监测设备还包括进气阀21,进气阀21的出气端与第一进气口和第二进气口均相连通,以确保两个通路共享一路进气口,保证测试准确性和一致性。进气阀21可为石英三通进气阀,其进气端与大气源连接,两个出气端分别与第一进气口和第二进气口连接,需保证接口处气密性良好。此外,石英三通进气阀和阳离子交换过滤装置23的第二进气口通过特氟龙连接管路22相连,特氟龙连接管路22具有高度的化学稳定性和优异的耐老化性,可长期于室外使用。
下面对本申请提供的分形态大气汞监测方法进行描述,下文描述的分形态大气汞监测方法与上文描述的分形态大气汞监测设备可相互对应参照。
本申请实施例还提供了一种分形态大气汞监测方法,基于如上述各实施例中的分形态大气汞监测设备,包括步骤:
采集环境大气样品;
通过气态氧化汞采集与热解析装置12捕集环境大气样品中含有的气态氧化汞,并通过颗粒汞采集与热解析装置11捕集环境大气样品中含有的颗粒汞;具体地,如图1所示,环境大气样品依次经过气态氧化汞采集与热解析装置12和颗粒汞采集与热解析装置11,分别捕集气态氧化汞和 颗粒汞;
获取经过气态氧化汞采集与热解析装置12和颗粒汞采集与热解析装置11后的环境大气样品中汞的总浓度,其中,汞的总浓度为气态元素汞和未捕集的气态氧化汞的总浓度;具体地,通过切换阀25控制第一出气口和第三进气口相连通,并通过冷原子荧光测汞仪15检测汞的总浓度;
通过阳离子交换过滤装置23捕集环境大气样品中含有的气态氧化汞和颗粒汞;
获取经过阳离子交换过滤装置23后的环境大气样品中气态元素汞的浓度;具体地,通过切换阀25控制第二出气口和第三进气口相连通,并通过冷原子荧光测汞仪15检测气态元素汞的浓度;
比较汞的总浓度和气态元素汞的浓度,并获取汞的总浓度与气态元素汞的浓度的差值,以得到未捕集的气态氧化汞的浓度;
解析气态氧化汞采集与热解析装置12捕集的气态氧化汞,并获取捕集的气态氧化汞的浓度。具体地,对气态氧化汞采集与热解析装置12进行零气吹扫,解析气态氧化汞。通过切换阀25控制第一出气口和第三进气口相连通,并通过冷原子荧光测汞仪15检测解析的气态氧化汞的浓度。
如此设置,通过获取并比较汞的总浓度和气态元素汞的浓度,从而得出准确的气态氧化汞的浓度,消除了气态氧化汞的分析误差,可以满足各种环境大气条件下的大气分形态汞准确监测需求。
此外,还可对颗粒汞采集与热解析装置11进行零气吹扫,解析颗粒汞。并通过冷原子荧光测汞仪15检测解析的颗粒汞的浓度。
具体来说,分形态大气汞监测设备单次采样完整流程为两小时,能够以两小时高时间分辨率分析大气中的气态元素汞、气态氧化汞和颗粒汞。其中,气态氧化汞和颗粒汞的测试方法分别为溶蚀管方法和石英滤膜法,并且操作和维护要求需要严格按照国际标准操作规程执行。基于此分形态大气汞监测设备,分形态大气汞监测方法的具体实施过程依次为:
颗粒汞采集与热解析装置11和气态氧化汞采集与热解析装置12采集环境空气,时长为20分钟;
阳离子交换过滤装置23采集环境空气,时长为20分钟;
气态氧化汞采集与热解析装置12和颗粒汞采集与热解析装置11采集 环境空气,时长为20分钟;
颗粒汞采集与热解析装置11和气态氧化汞采集与热解析装置12解析颗粒汞和气态氧化汞,时长为60分钟。其中,在解析过程中,先对颗粒汞采集与热解析装置11进行加热,解析颗粒汞。然后再对气态氧化汞采集与热解析装置12进行加热,解析气态氧化汞。
在采样过程中,通过颗粒汞采集与热解析装置11和气态氧化汞采集与热解析装置12采集环境空气的总流量设置范围为5LPM-15LPM,可选地,泵流量设置为9LPM。冷原子荧光测汞仪15的流量设置范围为0.5LPM-1.5LPM,可选地,泵流量设置为1LPM。
在单次采样流程的两小时内,每5分钟可采集分析得到一个汞浓度数据,一共可以分析出24个浓度数据,经过整理计算可以得到一组分形态汞数据。以2021年9月30日下午2-4时对北京市城区大气进行采样为例,其采样结果具体如表1所示。
Figure PCTCN2022117296-appb-000001
Figure PCTCN2022117296-appb-000002
表1 2021年9月30日下午2-4时环境空气采样结果
在两小时采样后,大气分形态汞的计算方法如以下公式所示:
Figure PCTCN2022117296-appb-000003
Figure PCTCN2022117296-appb-000004
Figure PCTCN2022117296-appb-000005
Figure PCTCN2022117296-appb-000006
其中,GEM是当前两小时循环的气态元素汞浓度,单位是ng m -3。TEK-GOM是基于溶蚀管方法得到的当前两小时循环的气态氧化汞浓度,单位是ng m -3。GOM是经过差减法核算得到的当前两小时循环的气态氧化汞浓度,单位是ng m -3。PBM是基于石英滤膜法得到的当前两小时循环的颗粒汞浓度,单位是ng m -3
本申请可以进行不同类型环境大气样品更加精准的分形态汞捕集解析和浓度分析,通过基于离子交换膜的阳离子交换过滤装置23将环境大气样品中的气态氧化汞和颗粒汞全部捕集,剩余的气态元素汞进入冷原子荧光测汞仪15测定,将经过颗粒汞采集与热解析装置11和气态氧化汞采集与热解析装置12得到的气态总汞和经过离子交换膜得到的气态元素汞进行比对,实现高时间分辨率大气分形态汞测定状态下的气态氧化汞的精准测量。
在相同的测试条件下,采用本申请的分形态大气汞监测设备和现有的在线分形态汞监测仪器,对2021年9月10日-2021年9月30日期间北京市城区大气中的分形态汞进行在线采集与分析。将采样结果进行比较,其对比结果如图3所示。本申请测试得到的GEM、GOM和PBM的浓度分别为3.02±1.21ng m -3、0.44±0.42ng m -3、0.056±0.10ng m -3。而现有在线分形态汞监测仪器测试得到的GOM浓度为0.20±0.22ng m -3。由图3可以明显地看出,气态氧化汞浓度在现有的观测方法中被明显低估。相比气态元素汞,气态氧化汞的化学性质更加活泼,准确地测定气态氧化汞对于大气汞循环和环境影响具有现实的指导意义。
此外,本申请还采用纯净HgBr 2气体测试基于离子交换膜的阳离子交换过滤装置23对于HgBr 2的捕集效率。其中,测试的HgBr 2浓度为1.3±0.1ng m -3,高于一般大气环境活性气态汞浓度。并且在相同的测试条件下,采用两个现有的基于溶蚀管的在线分形态汞监测仪测试对于HgBr 2的捕集效率。将测试结果进行比较,其对比结果如图2所示。由图2很明显可以看到,在洁净干燥空气条件下,本申请测试结果表明基于离子交换膜的阳离子交换过滤装置23能够以100%±9%的效率吸收二价汞,相比于现有常用的仪器,HgBr 2捕集效率提升了40%。因此,表明本申请的基于离子交换膜的阳离子交换过滤装置23具有较好的活性气态汞捕集性能。
综上所述,本申请提供了一种新型分形态大气汞监测设备及监测方法,包括颗粒汞采集与热解析装置11和气态氧化汞采集与热解析装置12,以及基于离子交换膜的阳离子交换过滤装置23。通过两个单元分别采集气态总汞和气态元素汞,并对比两路结果计算出大气中实际的气态氧化汞浓度,解决了现有环境大气样品分形态汞中气态氧化汞浓度检测不准确的问题。其时间分辨率高,可广泛适用于各类型环境大气的高效、稳定、便捷地捕集大气分形态汞,提高了在线监测效率和测试准确性。
最后应说明的是:以上实施例仅用以说明本申请的技术方案,而非对其限制;尽管参照前述实施例对本申请进行了详细的说明,本领域的普通技术人员应当理解:其依然可以对前述各实施例所记载的技术方案进行修改,或者对其中部分技术特征进行等同替换;而这些修改或者替换,并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围。

Claims (10)

  1. 一种分形态大气汞监测设备,包括:
    相连通的气态氧化汞采集与热解析装置和颗粒汞采集与热解析装置,所述气态氧化汞采集与热解析装置用于捕集和解析环境大气样品中含有的气态氧化汞,所述颗粒汞采集与热解析装置用于捕集和解析环境大气样品中含有的颗粒汞,所述气态氧化汞采集与热解析装置和所述颗粒汞采集与热解析装置二者之一设有第一进气口、另一者设有第一出气口;
    阳离子交换过滤装置,用于捕集环境大气样品中含有的气态氧化汞和颗粒汞,所述阳离子交换过滤装置设有第二进气口和第二出气口;
    冷原子荧光测汞仪,用于检测环境大气样品中含有的汞的浓度,所述冷原子荧光测汞仪设有第三进气口和第三出气口,所述第三进气口与所述第一出气口和所述第二出气口均相连接;
    切换阀,用于控制所述第一出气口和所述第二出气口中的一者与所述第三进气口相连通。
  2. 根据权利要求1所述的分形态大气汞监测设备,其中,所述阳离子交换过滤装置包括至少两层依次设置的阳离子交换过滤膜。
  3. 根据权利要求1所述的分形态大气汞监测设备,其中,还包括:
    伴热管,一端与所述第二出气口相连接、另一端与所述切换阀相连接;
    加热装置,设置在所述伴热管外。
  4. 根据权利要求1所述的分形态大气汞监测设备,其中,还包括流量计,用于检测进入所述冷原子荧光测汞仪的气体流量。
  5. 根据权利要求1所述的分形态大气汞监测设备,其中,还包括PM 2.5碰撞捕集器,用于过滤环境大气样品,所述第一进气口和/或所述第二进气口设有所述PM 2.5碰撞捕集器。
  6. 根据权利要求1所述的分形态大气汞监测设备,其中,还包括采样控制装置,所述采样控制装置与所述气态氧化汞采集与热解析装置、所述颗粒汞采集与热解析装置、所述阳离子交换过滤装置、所述冷原子荧光测汞仪和所述切换阀均电连接。
  7. 根据权利要求6所述的分形态大气汞监测设备,其中,所述气态 氧化汞采集与热解析装置包括:
    溶蚀管,用于捕集环境大气样品中含有的气态氧化汞;
    第一管式加热组件,设置在所述溶蚀管外,所述第一管式加热组件用于加热所述溶蚀管,以解析捕集的气态氧化汞;
    第一温度控制仪,用于控制所述第一管式加热组件的加热温度,且与所述采样控制装置电连接。
  8. 根据权利要求7所述的分形态大气汞监测设备,其中,所述颗粒汞采集与热解析装置包括:
    石英玻璃连接管,与所述溶蚀管相连通;
    石英截流滤膜,设置在所述石英玻璃连接管内,用于捕集环境大气样品中含有的颗粒汞;
    第二管式加热组件,设置在所述石英玻璃连接管外,所述第二管式加热组件位于所述石英玻璃连接管靠近所述石英截流滤膜的位置,所述第二管式加热组件用于加热所述石英玻璃连接管,以解析捕集的颗粒汞;
    第二温度控制仪,用于控制所述第二管式加热组件的加热温度,且与所述采样控制装置电连接。
  9. 根据权利要求1所述的分形态大气汞监测设备,其中,还包括进气阀,所述进气阀的出气端与所述第一进气口和所述第二进气口均相连通。
  10. 一种分形态大气汞监测方法,基于如权利要求1-9任一项所述的分形态大气汞监测设备,包括步骤:
    采集环境大气样品;
    通过气态氧化汞采集与热解析装置捕集环境大气样品中含有的气态氧化汞,并通过颗粒汞采集与热解析装置捕集环境大气样品中含有的颗粒汞;
    获取经过气态氧化汞采集与热解析装置和颗粒汞采集与热解析装置后的环境大气样品中汞的总浓度,其中,汞的总浓度为气态元素汞和未捕集的气态氧化汞的总浓度;
    通过阳离子交换过滤装置捕集环境大气样品中含有的气态氧化汞和颗粒汞;
    获取经过阳离子交换过滤装置后的环境大气样品中气态元素汞的浓度;
    比较汞的总浓度和气态元素汞的浓度,并获取汞的总浓度与气态元素汞的浓度的差值,以得到未捕集的气态氧化汞的浓度;
    解析气态氧化汞采集与热解析装置捕集的气态氧化汞,并获取捕集的气态氧化汞的浓度。
PCT/CN2022/117296 2021-11-24 2022-09-06 分形态大气汞监测设备及监测方法 WO2023093203A1 (zh)

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