A method and device for simulating PM2.5 in a laboratory to perform ozone aging under light

Abstract

The application discloses a kind of laboratory methods and devices for simulating PM2.5 ozone aging under light, which belongs to the technical field of simulated ozone aging, comprising: reactor, simulation lamp for irradiating reactor and ozone concentration detector for detecting the ozone concentration inside reactor;The inlet of the reactor is provided with an air pump and an ozone generator, the outlet of the air pump and the ozone generator is provided with a flowmeter, and the reactor is provided with a quartz filter membrane for loading PM sample;The device for ozone aging test is composed of simulation lamp, air pump, ozone generator, ozone concentration detector and reactor to overcome the defects of traditional equipment, and the sunlight can be controlled by using simulation lamp to simulate sunlight, and the overall space occupied by the device is small and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of simulated ozone aging technology, specifically to a method and apparatus for ozone aging in a laboratory using simulated PM2.5 under light irradiation. Background Technology

[0002] In recent years, PM2.5 concentrations have decreased significantly, but ozone concentrations have increased simultaneously. PM2.5 and ozone have become major air pollutants, influencing each other through complex atmospheric chemical and physical processes. The synergistic pollution of PM2.5 and ozone has become a hot topic in environmental pollution research. Furthermore, because PM2.5 has a strong absorption capacity for solar radiation, photochemical aging is also considered to affect the physical and chemical properties of atmospheric particulate matter. Therefore, studying the environmental chemical behavior of PM2.5 and ozone under sunlight requires a reaction device to simulate the ozone aging of PM2.5 under sunlight. Currently, the market... Ozone aging test chambers (such as the QL-100 from Wuxi Tengchuan Instrument Equipment Co., Ltd.) are available for sale. These chambers generate ozone gas through a silent ozone generator, and an ultraviolet detector continuously monitors the ozone concentration online. The control system controls the ozone concentration according to the set value and can also heat and humidify. However, this equipment cannot simulate sunlight and can only control the ozone concentration. Currently, some laboratories have also built smoke chambers. Under conditions where temperature and relative humidity can be controlled, ozone is introduced and artificial light sources are used to simulate photochemical reactions in the atmosphere. However, these devices are large in size, occupy a lot of laboratory space, and are expensive. Summary of the Invention

[0003] The purpose of this invention is to provide a method and apparatus for ozone aging under light using simulated PM2.5 in the laboratory, so as to solve the problem that ozone aging tests have certain limitations as mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a laboratory apparatus for simulating PM2.5 under light irradiation for ozone aging, comprising: a reactor, a simulated lamp for irradiating the reactor, and an ozone concentration detector for detecting the ozone concentration inside the reactor;

[0005] The reactor is equipped with an air pump and an ozone generator at its inlet, and flow meters at the outlets of both the air pump and the ozone generator. The reactor is also equipped with a quartz filter membrane for loading PM2.5 samples.

[0006] Preferably, the device further includes a fan for cooling the reactor, the reactor having a quartz sand core located between the quartz filter membrane and the reactor inlet.

[0007] Preferably, the ozone generator is equipped with a drying device at its air inlet.

[0008] Preferably, the simulated lamp is a xenon lamp, and the xenon lamp is mounted on the lifting device.

[0009] Preferably, the reactor inlet is provided with a connecting box, and the connecting box is provided with a filter screen.

[0010] Preferably, a rotating rod is rotatably provided inside the connecting box, and a cleaning brush for cleaning the filter screen is provided on the rotating rod. The air inlet of the connecting box is provided with a fan blade, and a transmission component for driving the rotating rod to rotate is provided on the shaft of the fan blade.

[0011] Preferably, a flip plate is provided on the side wall of the rotating rod;

[0012] The flipping plate includes a mounting plate, a movable plate slidably mounted on the mounting plate, and an elastic member disposed between the mounting plate and the movable plate. A stop block for blocking the outlet of the connecting box is slidably mounted on the connecting box. A flexible connecting member is provided between the stop block and the movable plate to drive the movable plate to block the outlet of the connecting box when the movable plate moves away from the mounting plate.

[0013] Preferably, a method for ozone aging of simulated PM2.5 in a laboratory under light irradiation, utilizing the aforementioned apparatus for ozone aging of simulated PM2.5 in a laboratory under light irradiation, includes the following steps:

[0014] S1: Collect PM2.5 samples onto a quartz filter membrane and place the quartz filter membrane into the reactor;

[0015] S2: Turn on the ozone generator and air pump. The generated ozone mixes with the air and enters the reactor, where it comes into full contact with the quartz filter membrane loaded with PM2.5 samples. The ozone is then discharged from the reactor. At the same time, turn on the simulated light to irradiate the reactor. After the preset time, remove the quartz filter membrane for testing.

[0016] Compared with the prior art, the beneficial effects of the present invention are: by using a device for ozone aging test consisting of a simulated lamp, an air pump, an ozone generator, an ozone concentration detector and a reactor, the defects of traditional equipment are overcome; by using a simulated lamp to simulate sunlight, the sunlight can be controlled; and the device occupies little space and has low cost. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the device structure for simulating ozone aging of PM2.5 under light irradiation according to the present invention;

[0018] Figure 2 This is a schematic diagram of the reactor structure of the present invention;

[0019] Figure 3 This is a schematic cross-sectional view of the communicating box structure of the present invention;

[0020] Figure 4 For the present invention Figure 3 Enlarged schematic diagram of the structure at point A in the middle;

[0021] Figure 5 This is a schematic diagram of the connection structure between the mounting plate and the movable plate of the present invention;

[0022] Figure 6 These are scanning electron microscope images of PM2.5 before and after treatment according to the present invention;

[0023] Figure 7 The images are Fourier transform infrared spectra before and after PM2.5 treatment according to this invention.

[0024] Figure 8 The image shows the C1s fitted spectra of X-ray photoelectron spectroscopy before and after PM2.5 treatment according to this invention.

[0025] Figure 9 This is a data diagram of C1s spectrum fitting before and after PM2.5 treatment according to the present invention.

[0026] In the diagram: 1. Simulated light; 2. Fan; 3. Air pump; 4. Ozone generator; 5. Flow meter; 6. Ozone concentration detector; 7. Reactor; 8. Quartz sand core; 9. Air inlet; 10. Air outlet; 11. Connecting box; 12. Filter screen; 13. Fan blade; 14. Rotating rod; 15. Cleaning brush; 16. Flipping plate; 161. Mounting plate; 162. Movable plate; 163. Elastic element; 17. Flexible connector; 18. Stop block. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1

[0029] Please see Figure 1 A laboratory apparatus for simulating PM2.5 under light irradiation for ozone aging includes: a simulation lamp 1, an ozone concentration detector 6, and a reactor 7; the simulation lamp 1 is a xenon lamp, and the ozone concentration detector 6 is connected to the reactor 7 to detect the ozone concentration inside the reactor 7.

[0030] It should be noted that the xenon lamp is used with an AM1.5G filter and a total internal reflection filter to simulate the solar spectrum; the xenon lamp can replace the filter to achieve the required specific wavelength spectrum; the xenon lamp is placed on a lifting device (lifting platform) to adjust the height of the xenon lamp.

[0031] It should also be noted that reactor 7 is a quartz reactor, designed as a fluidized bed, with the main body consisting of a cylinder and an enlarged section at the top (e.g., Figure 2 As shown), the cylinder and the expansion section are connected by a flange and can be disassembled; the inlet of reactor 7 is the air inlet 9 opened at the bottom of reactor 7, the outlet of reactor 7 is the air outlet 10 opened at the top of reactor 7, and another gas outlet is opened upward on the side wall of the expansion section for connecting to the ozone concentration detector 6.

[0032] Please see Figure 1 and Figure 2 The device for simulating PM2.5 ozone aging under light also includes an air pump 3 and an ozone generator 4. The outlet end of the air pump 3 and the outlet end of the ozone generator 4 are respectively connected to a flow meter 5 and then connected to the air inlet 9 of the reactor 7 through a U-shaped glass connecting tube. The reactor 7 is equipped with a quartz filter membrane, which is used to load PM2.5 samples.

[0033] It should be noted that the pipes used in the device are ozone-resistant silicone tubing; the flow meter 5 connected to the ozone generator 4 is an ozone-resistant flow meter to avoid corrosion from the strong oxidizing properties of ozone.

[0034] A laboratory method for ozone aging using simulated PM2.5 under light irradiation, comprising the following steps:

[0035] A high-flow-rate gas sampler was used at 1.05m 3 PM2.5 samples were collected at a sampling flow rate of / min onto a quartz filter membrane, which was then cut using ceramic scissors (5×5cm). 2 The reactor 7 was opened, and a sheared quartz filter membrane was placed inside. The ozone generator 4 and the simulation lamp 1 were turned on to generate ozone using an air source. The flow meter 5 was adjusted to control the ozone flow rate at 20 mL / min and the air pump 3 flow rate at 1.6 L / min, controlling the ozone concentration at 0.8 ± 0.1 ppm. The two gases were mixed, and the mixed gas flow was introduced into the reactor 7 to continuously ozone age the PM2.5 sample on the quartz filter membrane for 14 hours. During the ozone aging period, the xenon lamp was used for intermittent illumination at 1-hour intervals, for a total of 7 hours of illumination. The gas was discharged from the outlet 10 of the reactor 7.

[0036] It should be noted that after the aging treatment, the quartz filter membrane containing PM2.5 samples was removed and imaged using a scanning electron microscope (SEM) to observe the morphological changes of PM2.5; Fourier transform attenuated total reflectance infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were measured to analyze the changes in surface functional groups and oxygen-carbon ratio of PM2.5 after aging; the physicochemical properties of PM2.5 before and after ozone aging under light are characterized as follows: Figures 6-9 As shown.

[0037] Experimental results revealed that: SEM images showed that the typical sulfate analogs of PM2.5, which were originally smooth and regularly shaped, had undergone morphological damage; infrared spectroscopy revealed changes in the functional groups of PM2.5, with the characteristic peaks of carbon-oxygen double bonds decreasing and the characteristic peaks of carbon-oxygen single bonds increasing; charge correction and peak fitting of the C1s high-resolution spectrum of XPS showed that the peak area ratio of oxygen-containing functional groups in PM2.5 changed after aging, with an increase in the oxygen-to-carbon ratio; thus, the method of this invention for ozone aging of PM2.5 under illumination can simulate the ozone aging behavior of PM2.5 in the atmosphere.

[0038] In this embodiment, as a further optimization, please refer to... Figure 1 and Figure 2 The device also includes a fan 2, which can dissipate heat and reduce the impact of xenon lamp illumination on temperature; a quartz sand core 8 is installed inside the reactor 7, which is located between the quartz filter membrane and the inlet of the reactor 7; the mixed gas is dispersed by the quartz sand core 8 and then comes into full contact with the quartz filter membrane loaded with PM2.5; a drying device (e.g., a moisture filter drying cylinder) is installed on the air inlet of the ozone generator 4 to prevent humid air from affecting ozone generation.

[0039] Example 2

[0040] As a further optimization of Example 1, please refer to Figure 2 and Figure 3 The reactor 7 is equipped with a connecting box 11 at its inlet. The outlet of the connecting box 11 is connected to the air inlet 9 of the reactor 7. The inlet of the connecting box 11 is connected to a U-shaped glass connecting pipe. A filter screen 12 is installed in the inner cavity of the connecting box 11. The filter screen 12 filters the mixed gas entering the reactor 7, removing large particulate impurities mixed in the gas. After the mixed gas enters the interior of the connecting box 11, the pressure of the gas decreases due to the increased space, thereby reducing the impact force when the mixed gas enters the reactor 7. This reduces the impact force on the quartz filter membrane, lowering the probability of the quartz filter membrane shifting and deviating inside the reactor 7.

[0041] In this embodiment, as a further optimization, please refer to... Figure 3A rotating rod 14 is rotatably installed inside the cavity of the connecting box 11. A cleaning brush 15 is provided on the side wall of the rotating rod 14. The cleaning brush 15 is attached to the bottom wall of the filter screen 12. A fan blade is provided in the air inlet of the connecting box 11. A transmission assembly for driving the rotating rod 14 to rotate is provided on the shaft of the fan blade 13 (the transmission assembly includes two gears, which are respectively sleeved on the shaft of the fan blade 13 and the outer wall of the rotating rod 14, and the two gears mesh with each other). During the process of the mixed gas entering the interior of the connecting box 11 through the inlet, the mixed gas will carry the fan blade 13 to rotate, causing the rotating rod 14 to rotate together, and causing the cleaning brush 15 to clean the bottom of the filter screen 12 to prevent the filter screen 12 from clogging.

[0042] In this embodiment, as a further optimization, please refer to... Figure 3 , Figure 4 and Figure 5 A flipping plate 16 is provided on the side wall of the rotating rod 14; the flipping plate 16 includes a mounting plate 161, a movable plate 162 slidably mounted on the mounting plate 161, and an elastic element 163 (spring) provided between the mounting plate 161 and the movable plate 162. The mounting plate 161 is mounted on the side wall of the rotating rod 14. A stop block 18 is slidably provided on the top of the inner cavity of the connecting box 11. A return spring is installed between the stop block 18 and the connecting box 11. A flexible connector 17 (rope, but not limited to rope) is provided on the stop block 18. A guide hole is provided on the inner wall of the connecting box 11. An opening is provided at the end of the rotating rod 14 (the opening is located on the axis of the rotating rod 14). The end of the flexible connector 17 away from the stop block 18 passes through the guide hole and the opening and is connected to the movable plate 162; When the lever 14 rotates, causing the flip plate 16 to rotate, the flip plate 16 can mix the gas inside the connecting box 11, ensuring uniform gas mixing. Furthermore, the flip plate 16 is subjected to centrifugal force as it rotates with the lever 14. When the flow rate of the mixed gas entering the connecting box 11 is relatively fast, the speed of the fan blade 13 is relatively fast, which will increase the speed of the lever 14. This will increase the centrifugal force on the movable plate 162 of the flip plate 16, causing it to move away from the lever 14. When the movable plate 162 moves, it will pull the flexible connector 17, causing the baffle 18 to move and block the outlet of the connecting box 11, reducing the size of the outlet of the connecting box 11 and reducing the gas output of the connecting box 11. This will reduce the impact on the quartz filter membrane when the mixed gas enters the reactor 7.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A laboratory apparatus for simulating PM2.5 ozone aging under light irradiation, characterized in that: include: Reactor (7), a simulated lamp (1) for irradiating the reactor (7), and an ozone concentration detector (6) for detecting the ozone concentration inside the reactor (7). The reactor (7) is equipped with an air pump (3) and an ozone generator (4) at its inlet. The air pump (3) and the ozone generator (4) are both equipped with flow meters (5) at their outlets. The reactor (7) is equipped with a quartz filter membrane for loading PM2.5 samples. The reactor (7) is provided with a connecting box (11) at the inlet, and a filter screen (12) is provided inside the connecting box (11). After the mixed gas enters the interior of the connecting box (11), the space increases, reducing the impact force of the mixed gas entering the reactor (7) on the quartz filter membrane. The connecting box (11) is rotatably provided with a rotating rod (14), and the rotating rod (14) is provided with a cleaning brush (15) for cleaning the filter screen (12). The air inlet of the connecting box (11) is provided with a fan blade (13), and the shaft of the fan blade (13) is provided with a transmission component for driving the rotating rod (14) to rotate. The rotating rod (14) has a flip plate (16) on its side wall. The flipping plate (16) includes a mounting plate (161), a movable plate (162) slidably mounted on the mounting plate (161), and an elastic member (163) disposed between the mounting plate (161) and the movable plate (162). A stop (18) for blocking the outlet of the connecting box (11) is slidably provided on the connecting box (11). A flexible connector (17) is provided between the stop (18) and the movable plate (162) to drive the movable plate (162) toward the connecting box when the movable plate (162) moves away from the mounting plate (161). (11) The outlet is blocked; when the flow rate of the mixed gas into the connecting box (11) is fast, the speed of the fan blade (13) is fast, which makes the moving plate (162) of the flipping plate (16) subject to increased centrifugal force and move away from the rotating rod (14), pulling the flexible connector (17), causing the baffle (18) to move to block the outlet of the connecting box (11), reducing the size of the gas outlet of the connecting box (11), reducing the gas output of the connecting box (11), thereby reducing the impact on the quartz filter membrane when the mixed gas enters the reactor (7).

2. The apparatus for simulating PM2.5 ozone aging under light in a laboratory setting according to claim 1, characterized in that: The device also includes a fan (2) for cooling the reactor (7), which is equipped with a quartz sand core (8) located between the quartz filter membrane and the inlet of the reactor (7).

3. The apparatus for simulating PM2.5 ozone aging under light in a laboratory setting according to claim 1, characterized in that: The ozone generator (4) is equipped with a drying device at its air inlet.

4. The apparatus for simulating PM2.5 ozone aging under light in a laboratory setting according to claim 1, characterized in that: The simulated lamp (1) is a xenon lamp, which is installed on the lifting device.

5. A method for ozone aging of simulated PM2.5 in a laboratory under light irradiation, utilizing the apparatus for ozone aging of simulated PM2.5 in a laboratory under light irradiation as described in any one of claims 1-4, characterized in that: Includes the following steps: S1: Collect PM2.5 samples onto a quartz filter membrane and place the quartz filter membrane into the reactor (7); S2: Turn on the ozone generator (4) and air pump (3). The generated ozone mixes with the air and enters the reactor (7), making full contact with the quartz filter membrane loaded with PM2.5 sample, and then discharges from the reactor (7). At the same time, turn on the simulation lamp (1) to irradiate the reactor (7). After the preset time, take out the quartz filter membrane for testing.

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