Method and device for simulating ozone aging of PM2.5 under illumination in laboratory

Abstract

The invention discloses a method and a device for simulating ozone aging of PM2.5 under illumination in a laboratory in the technical field of ozone aging simulation. The device comprises a reactor, a simulation lamp for irradiating the reactor and an ozone concentration detector for detecting the ozone concentration in the reactor, an air pump and an ozone generator are arranged at an inlet of the reactor, flow meters are arranged at outlets of the air pump and the ozone generator, and a quartz filter membrane for loading a PM. Sample is arranged in the reactor; the ozone aging test device composed of the simulation lamp, the air pump, the ozone generator, the ozone concentration detector, the reactor and the like overcomes the defects of traditional equipment, the simulation lamp is used for simulating sun illumination, the sun illumination can be controlled, and the whole device is small in occupied space and low in cost.

Description

Technical Field

[0001] The invention relates to the technical field of simulated ozone aging, and specifically to a method and a device for ozone aging of simulated PM2.5 under light in a laboratory. Background Art

[0002] In recent years, the concentration of PM2.5 has dropped significantly, but at the same time the concentration of ozone has increased. PM2.5 and ozone have become the main atmospheric pollutants. The two affect each other through complex atmospheric chemical and physical processes. The synergistic pollution of PM2.5 and ozone has become a hot issue in environmental pollution research. In addition, because PM2.5 has a strong absorption of solar radiation, photochemical aging is also believed to affect the physical and chemical properties of atmospheric particulate matter. When studying the environmental chemical behavior of PM2.5 and ozone under sunlight conditions, a reaction device is needed to simulate the ozone aging of PM2.5 under light. There are ozone aging test chambers for sale (such as the QL-100 produced by Wuxi Tengchuan Instrument Equipment Co., Ltd.). Ozone gas is generated by a silent ozone generator, and the ozone concentration is continuously detected online by a UV detector. The control system controls the ozone concentration according to the set value and can heat and humidify at the same time. However, the equipment cannot simulate sunlight and can only control the ozone concentration. At present, some laboratories have built smoke chambers, which introduce ozone and use artificial light to simulate photochemical reactions in the atmosphere under conditions where the temperature and relative humidity can be controlled. However, such devices are large in size, take up a large laboratory space, and are expensive. Summary of the invention

[0003] The purpose of the present invention is to provide a method and device for ozone aging of simulated PM2.5 under light in a laboratory, so as to solve the problem that the ozone aging test proposed in the above background technology has certain limitations.

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

[0005] An air pump and an ozone generator are provided at the inlet of the reactor, flow meters are provided at the outlets of the air pump and the ozone generator, and a quartz filter membrane for loading PM2.5 samples is provided in the reactor.

[0006] Preferably, the device further comprises a fan for cooling the reactor, and a quartz sand core is provided in the reactor, wherein the quartz sand core is located between the quartz filter membrane and the inlet of the reactor.

[0007] Preferably, a drying device is provided on the air inlet of the ozone generator.

[0008] Preferably, the simulation lamp is a xenon lamp, and the xenon lamp is arranged on a lifting device.

[0009] Preferably, a connecting box is provided on the inlet of the reactor, and a filter is provided in the connecting box.

[0010] Preferably, a rotating rod is rotatably provided in the connecting box, a cleaning brush for cleaning the filter is provided on the rotating rod, a fan blade is provided at the air inlet of the connecting box, and a transmission assembly for driving the rotating rod to rotate is provided on the shaft of the fan blade.

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

[0012] Among them, the flip plate includes a mounting plate, a movable plate slidably arranged on the mounting plate, and an elastic member arranged between the mounting plate and the movable plate. A block for blocking the outlet of the connecting box is slidably arranged on the connecting box. A flexible connecting member is provided between the block and the movable plate to drive the movable plate to block the outlet of the connecting box when the movable plate is away from the mounting plate.

[0013] Preferably, a method for ozone aging of simulated PM2.5 under light in a laboratory, using the above-mentioned device for ozone aging of simulated PM2.5 under light in a laboratory, comprises the following steps:

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

[0015] S2: Turn on the ozone generator and the air pump. The generated ozone mixes with the air and enters the reactor. It fully contacts the quartz filter membrane loaded with the PM2.5 sample and is then discharged from the reactor. At the same time, turn on the simulation lamp to irradiate the reactor. After the preset time, take out the quartz filter membrane for testing.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: the device for ozone aging test composed of a simulation lamp, an air pump, an ozone generator, an ozone concentration detector and a reactor overcomes the defects of traditional equipment, and the simulation lamp is used to simulate sunlight, so that the sunlight can be controlled, and the overall device occupies a small space and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0019] Figure 3 It is a schematic diagram of the cross-sectional structure of the connecting box of the present invention;

[0020] Figure 4 For the present invention Figure 3 A schematic diagram of the structure enlargement 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 The scanning electron microscope images before and after PM2.5 treatment of the present invention;

[0023] Figure 7 It is the Fourier infrared spectrum image before and after PM2.5 treatment of the present invention;

[0024] Figure 8 It is the C1s fitting spectrum of the X-ray photoelectron spectrum before and after PM2.5 treatment of the present invention;

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

[0026] In the figure: 1. simulation lamp; 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; 13. fan blade; 14. rotating rod; 15. cleaning brush; 16. flip plate; 161. mounting plate; 162. movable plate; 163. elastic member; 17. flexible connector; 18. stopper. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] See also Figure 1 A laboratory device for simulating PM2.5 to undergo ozone aging under light 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 for detecting the ozone concentration inside the reactor 7.

[0030] It should be noted that the xenon lamp is used with AM1.5G filter and total reflection filter to simulate the solar spectrum; the xenon lamp can replace the filter to meet the needs of specific band 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 the reactor 7 is a quartz reactor designed in the shape of a fluidized bed, and the main body includes a cylindrical body and an enlarged section (such as Figure 2 As shown), the cylinder and the expansion section are connected by a flange in the middle and can be disassembled; the inlet of the reactor 7 is an air inlet 9 opened at the bottom of the reactor 7, the outlet of the reactor 7 is an air outlet 10 opened at the top of the reactor 7, and another gas outlet is opened upward on the side wall of the expansion section for connecting the ozone concentration detector 6.

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

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

[0034] A laboratory method for ozone aging using simulated PM2.5 under light, the steps are as follows:

[0035] Use a large flow gas sampler at 1.05m 3 The PM2.5 samples were collected on the quartz filter membrane at a sampling rate of / min, and the quartz filter membrane (5×5cm) was cut using ceramic scissors. 2 ), open the reactor 7, put in the sheared quartz filter membrane; turn on the ozone generator 4 and the simulation lamp 1, use the air source to generate ozone, adjust the flowmeter 5, the ozone flowmeter 5 flow rate is controlled at 20mL / min, the flowmeter 5 of the air pump 3 flow rate is controlled at 1.6L / min, and the ozone concentration is controlled to be 0.8±0.1ppm. The two gases are mixed, and the mixed gas flow is connected to the reactor 7. The PM2.5 sample on the quartz filter membrane is continuously ozone aged for 14h. During the ozone aging period, the xenon lamp is illuminated at intervals of 1h, for a total of 7h, and the gas is discharged from the outlet 10 of the reactor 7.

[0036] It should be noted that after the aging treatment, the quartz filter containing the PM2.5 sample was taken out for scanning electron microscopy (SEM) to observe the morphological changes of PM2.5; the Fourier transform attenuated total reflection infrared spectrum (FTIR) and X-ray photoelectron spectroscopy (XPS) were measured to analyze the changes in the surface functional groups and oxygen-carbon ratio of PM2.5 after aging; the physical and chemical properties of PM2.5 before and after ozone aging under light were characterized as follows Figure 6-9 shown.

[0037] The experimental results show that: through SEM images, it can be observed that the typical component sulfate analogue of PM2.5 has been damaged in its smooth and regular rectangular sulfate analogue morphology; from the infrared spectrum, it can be seen that the functional groups of PM2.5 have changed, the characteristic peak of the carbon-oxygen double bond has decreased, and the characteristic peak of the carbon-oxygen single bond has increased; the C1s high-resolution spectrum of XPS was subjected to charge correction and peak fitting, and the peak area ratio of the oxygen-containing functional groups of PM2.5 changed after aging, and the oxygen-carbon ratio increased; thus, the method of the present invention can be used to perform ozone aging on PM2.5 under light to simulate the ozone aging behavior of PM2.5 in the atmosphere.

[0038] In this embodiment, as a further optimized solution, please refer to Figure 1 and Figure 2 The device also includes a fan 2, which can dissipate heat and reduce the temperature, thereby reducing the impact of xenon lamp illumination on the temperature; a quartz sand core 8 is provided in the reactor 7, and the quartz sand core 8 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 fully contacts with the quartz filter membrane loaded with PM2.5; a drying device (such as a moisture filter drying cylinder) is provided on the air inlet of the ozone generator 4 to prevent humid air from affecting the generation of ozone.

[0039] Example 2

[0040] As a further optimized solution of Example 1, please refer to Figure 2 and Figure 3 A connecting box 11 is provided on the inlet of the reactor 7, 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 the U-shaped glass connecting pipe, and a filter screen 12 is provided in the inner cavity of the connecting box 11; the mixed gas entering the reactor 7 is filtered by the filter screen 12 to remove large particles of impurities mixed in the gas; after the mixed gas enters the inside of the connecting box 11, the pressure of the gas is reduced due to the increase in space, thereby reducing the impact force of the mixed gas when entering the reactor 7, reducing the impact force on the quartz filter membrane, and reducing the probability of the quartz filter membrane moving inside the reactor 7 and deviating.

[0041] In this embodiment, as a further optimized solution, please refer to Figure 3A rotating rod 14 is rotatably provided in the inner cavity of the connecting box 11, and a cleaning brush 15 is provided on the side wall of the rotating rod 14, and the cleaning brush 15 is in contact with the bottom wall of the filter 12. A fan blade is provided in the air inlet of the connecting box 11, and 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, and the two gears are respectively mounted on the shaft of the fan blade 13 and the outer wall of the rotating rod 14, and the two gears are meshed with each other); in the process of the mixed gas entering the interior of the connecting box 11 through the inlet of the connecting box 11, the mixed gas will rotate with the fan blade 13, causing the rotating rod 14 to rotate together, and causing the cleaning brush 15 to clean the bottom of the filter 12 to prevent the filter 12 from being blocked.

[0042] In this embodiment, as a further optimized solution, please refer to Figure 3 , Figure 4 and Figure 5 , a flap plate 16 is provided on the side wall of the rotating rod 14; the flap plate 16 includes a mounting plate 161, a movable plate 162 slidably arranged on the mounting plate 161, and an elastic member 163 (spring) arranged between the mounting plate 161 and the movable plate 162, the mounting plate 161 is installed on the side wall of the rotating rod 14, a stopper 18 is slidably provided on the top of the inner cavity of the connecting box 11, a return spring is installed between the stopper 18 and the connecting box 11, a flexible connecting member 17 (rope, but not limited to rope) is provided on the stopper 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), and one end of the flexible connecting member 17 away from the stopper 18 passes through the guide hole and the opening and is connected to the movable plate 162; in the rotating When the rod 14 rotates with the flap plate 16, the flap plate 16 can mix the gas inside the connecting box 11 to ensure that the gas is evenly mixed; and the flap plate 16 will be affected by centrifugal force when the rotating rod 14 rotates. When the flow rate of the mixed gas entering the connecting box 11 is faster, the rotation speed of the fan blade 13 is faster, which will increase the rotation speed of the rotating rod 14, so that the movable plate 162 of the flap plate 16 is affected by the increased centrifugal force and moves away from the rotating rod 14. When the movable plate 162 moves, it will pull the flexible connector 17 to move the block 18 to block the outlet of the connecting box 11, reduce the size of the gas outlet of the connecting box 11, and reduce the gas outlet of the connecting box 11, thereby reducing the impact of the mixed gas on the quartz filter membrane when entering the reactor 7.

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

Claims

1. A laboratory device for simulating PM2.5 ozone aging under light, characterized by: include: A reactor (7), a simulation lamp (1) for irradiating the reactor (7), and an ozone concentration detector (6) for detecting the ozone concentration inside the reactor (7); An air pump (3) and an ozone generator (4) are provided at the inlet of the reactor (7), and flow meters (5) are provided at the outlets of the air pump (3) and the ozone generator (4). A quartz filter membrane for loading PM2.5 samples is provided in the reactor (7).

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

3. The device for simulating PM2.5 under ozone aging in a laboratory according to claim 1, characterized in that: A drying device is provided on the air inlet of the ozone generator (4).

4. The device for simulating PM2.5 under ozone aging in a laboratory according to claim 1, characterized in that: The simulation lamp (1) is a xenon lamp, and the xenon lamp is arranged on a lifting device.

5. The device for simulating PM2.5 under ozone aging in a laboratory according to claim 1, characterized in that: A connecting box (11) is provided at the inlet of the reactor (7), and a filter screen (12) is provided inside the connecting box (11).

6. The device for simulating PM2.5 under ozone aging in a laboratory according to claim 5, characterized in that: A rotating rod (14) is rotatably arranged in the connecting box (11), and a cleaning brush (15) for cleaning the filter (12) is arranged on the rotating rod (14); a fan blade (13) is arranged at the air inlet of the connecting box (11), and a transmission assembly for driving the rotating rod (14) to rotate is arranged on the shaft of the fan blade (13).

7. The device for simulating ozone aging of PM2.5 in a laboratory under light according to claim 6, characterized in that: A flap plate (16) is provided on the side wall of the rotating rod (14); The flip plate (16) comprises a mounting plate (161), a movable plate (162) slidably arranged on the mounting plate (161), and an elastic member (163) arranged between the mounting plate (161) and the movable plate (162); a stopper (18) for blocking the outlet of the connecting box (11) is slidably arranged on the connecting box (11); a flexible connecting member (17) is arranged between the stopper (18) and the movable plate (162) so as to drive the movable plate (162) to block the outlet of the connecting box (11) when the movable plate (162) is away from the mounting plate (161).

8. A method for ozone aging of simulated PM2.5 in a laboratory under light, using a device for ozone aging of simulated PM2.5 in a laboratory under light as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Collect the PM2.5 sample onto a quartz filter membrane, and place the quartz filter membrane into a reactor (7); S2: Turn on the ozone generator (4) and the air pump (3), and the generated ozone is mixed with the air and enters the reactor (7), fully contacts the quartz filter membrane loaded with the PM2.5 sample, and then is discharged from the reactor (7). At the same time, turn on the simulation lamp (1) to irradiate the reactor (7). After a preset time, the quartz filter membrane is taken out for detection.

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